Fungicidal compositions based on phosphorous acid esters and salts thereof

Abstract

Compositions for controlling fungus disease are disclosed which contain as active material a fungicidally effective amount of at least one compound of the formula ##STR1## IN WHICH R is an optionally halogenated or nitrated, linear or branched alkyl radical containing from 1 to 18 carbon atoms and preferably from 1 to 8 carbon atoms, an optionally halogenated alkenyl or alkinyl radical, an alkoxy alkyl radical, an alkenoxy alkyl radical, the hydrocarbon portion of these four types of radicals containing from 1 to 8 and preferably from 1 to 5 carbon atoms, a cyclohexyl radical, an optionally substituted aryl radical, preferably phenyl, or aryl alkyl radical, preferably phenyl alkyl, or even a heterocyclic radical optionally attached to the oxygen through an aliphatic chain, preferably tetrahydrofurfuryl, M represents an ammonium cation, ammonium substituted by 1 to 4 alkyl or hydroxy alkyl radicals containing from 1 to 5 carbon atoms or by 1 to 2 cyclohexyl radicals or a phenyl radical, or a cation of a metal from the group comprising the alkali metals, preferably sodium and potassium, alkaline earth metals, preferably magnesium, barium, calcium, and polyvalent metals such as, preferably, zinc, manganese, copper(I) and (II), iron, nickel, aluminium,N is an integer equal to the valency of M.

Description

This invention relates to fungicidal compositions based on monoesters of phosphorous acid (or phosphites) and their salts. These compounds are sometimes also referred to as monoalkyl (aryl . . . ) phosphites.

More particularly, the invention relates to compositions which are suitable for use in controlling parasitic fungi in plants and which contain, as their active material, at least one compound corresponding to the general formula: ##STR2## IN WHICH R is an optionally halogenated or nitrated, linear or branched alkyl radical containing from 1 to 18 carbon atoms and preferably from 1 to 8 carbon atoms, an optionally halogenated alkenyl or alkinyl radical, an alkoxy alkyl radical, an alkenoxy alkyl radical, the hydrocarbon portion of these four types of radicals containing from 1 to 8 and preferably from 1 to 5 carbon atoms, a cyclohexyl radical, an optionally substituted aryl radical, preferably phenyl, or aryl alkyl radical, preferably phenyl alkyl, or even a heterocyclic radical optionally attached to the oxygen through an aliphatic chain, preferably tetrahydrofurfuryl,

M represents an hydrogen atom ammonium cation, ammonium substituted by 1 to 4 alkyl or hydroxy alkyl radicals containing from 1 to 5 carbon atoms or by 1 to 2 cyclohexyl radicals or a phenyl radical, or a cation of a metal from the group comprising the alkali metals, preferably sodium and potassium, alkaline earth metals, preferably magnesium, barium, calcium, and polyvalent metals such as, preferably, zinc, manganese, copper(I) and (II), iron, nickel, aluminum, N is an integer equal to the valency of M.

Some of these compounds are known per se. V. V. Orlovski et al, Journal of Gen. Chem. USSR, Vol. 42, p. 1924 (1972) describe the preparation of numerous salts of monoalkyl phosphites and, in particular, monoethyl phosphites with metallic or ammonium cations substituted to a greater or lesser extent, although they do not mention the fact that these compounds have fungicidal properties.

It has now been found that the compounds according to the invention show excellent fungicidal properties, especially with respect to various types of mildew, such as mildew of the vine, tobacco mildew and hop mildew.

These compounds may be obtained by the following general methods (cf. Houben-Weyl, Vol. XII/2).

First of all, phosphites may be prepared by transesterifying a dialkyl phosphite with phosphorous acid (E. E. NIFANTEV, L. P. LEVITAN, C.A. 1107e 1966) in accordance with the following scheme: ##STR3##

O-ethyl phosphite was prepared by this process: an equimolecuar mixture of O,O-diethyl phosphite and phosphorous acid is heated for 6 hours to 150.degree. C. A liquid of index n.sub.D.sup.20 = 1.4211 and of density d = 1.0043 (20.degree. C.) is obtained in a quantitative yield.

The following compounds may also be prepared by this method: O-methyl phosphite, O-n-hexyl phosphite, O-isooctyl phosphite, O-n-nonyl phosphite, O-n-decyl phosphite, O-n-dodecyl phosphite, O-n-hexadecyl phosphite, O-cyclohexyl phosphite, O-phenyl phosphite, O-benzyl phosphite.

It is also possible to obtain (cf. Houben-Weyl, Vol. XII/2, page 6) esters according to the invention by hydrolyzing a phosphorous acid dichloride with two equivalents of water in accordance with the following scheme: ##STR4##

O-octyl phosphite in particular may be prepared by this method.

So far as the salts are concerned, they may be prepared by at least two methods: the first (cf. Houben-Weyl, Vol, XII, page 7) comprises hydrolyzing or saponifying an O,O-dialkyl phosphite in accordance with the following scheme: ##STR5##

This method is particularly suitable for alkali metal salts and ammonium salts.

I - Alkali metal and ammonium salts

Saponification is carried out with a mineral or organic base in aqueous solution. The reaction takes place in 1 to 4 hours at a temperature ranging from ambient temperature to the reflux temperature (aqueous medium). The products obtained, which are liquids or solids generally soluble in water, are separated by eliminating the water and the solvent, if any.

Sodium O-ethyl phosphite was prepared in this way. One equivalent of soda in hydroalcoholic solution is added dropwise with stirring to a hydroalcoholic solution of O,O-diethyl phosphite. After standing for 2 hours, the alcohol and water are removed by distillation under reduced pressure in a water bath. The solid residue is recrystallized from absolute alcohol.

Melting point: > 300.degree. C., yield: 68%. ______________________________________Analysis for C.sub.2 H.sub.6 O.sub.3 Na P% C H P______________________________________Calculated 18.18 4.54 23.45Found 18.18 4.63 23.38______________________________________

The following salts were prepared by this method:

______________________________________sodium O-methyl phosphite m.p. 125.degree. Csodium O-n-propyl phosphite m.p. 195-196.degree. Csodium O-isopropyl phosphite m.p. 132-133.degree. Csodium O-n-butyl phosphite m.p. 178.degree. Csodium O-n-octyl phosphite m.p. 167.degree. Csodium O-n-dodecyl phosphite m.p. 100.degree. Csodium O-n-hexadecyl phosphite m.p. 52.degree. C______________________________________

The ammonium salts are obtained in the following manner illustrated for ammonium O-ethyl phosphite:

0.036 mole of O,O-diethyl phosphite are dissolved in a 25% aqueous ammonia solution. After standing for 1 hour, the solution is evaporated under reduced pressure in a water bath. The initially rubbery and colorless residue crystallized. Crystals in the form of colorless needles are obtained by crystallization in a mixture of ethanol and acetone.

Yield: 87%, m.p.: 99.degree.-100.degree. C. ______________________________________Analysis for C.sub.2 H.sub.10 NO.sub.3 P% C H N P______________________________________Calculated 18.90 7.87 11.02 24.41Found 18.93 7.90 11.10 24.29______________________________________

Other alkali metal salts, whose characteristics and, where necessary, the particular preparation conditions are shown in the following Tables 1 and 1A, were obtained by changing the saponification base and/or the alkyl radical in the procedure described above:

Table 1__________________________________________________________________________ ##STR6## formulaEmperical constantsPhysicals Yield Centesimal analysis % Calculated__________________________________________________________________________ Found ##STR7## C.sub.4 H.sub.14 NO.sub.3 P PF 164.5.degree. 62% C H N P 31.00 9.03 9.03 31.04 9.05 9.18 20.13 ##STR8## C.sub.8 H.sub.22 NO.sub.3 P -- 82% C H N P 45.50 10.43 6.64 44.26 10.08 6.79 16.10 ##STR9## C.sub.6 H.sub.18 NO.sub.3 P -- 34% C H N P 39.30 9.85 7.65 37.19 9.80 7.78 17.89 ##STR10## C.sub.2 H.sub.9 ClNO.sub.3 P 62% C H N P 14.87 5.57 8.67 14.78 5.69 8.70 19.19 ##STR11## C.sub.3 H.sub.12 NO.sub.4 P PF 56.5.degree. 79% C H N P 22.93 7.65 8.92 22.87 7.65 8.89 19.90 ##STR12## CH.sub.8 NO.sub.3 P hygroscopic product 79% C H N P 10.62 7.08 12.39 10.76 7.02 12.37 27.30 ##STR13## C.sub.3 H.sub.12 NO.sub.3 P hygroscopic product 100% C H N P 25.53 8.51 9.93 25.76 8.66 9.93 21.67 ##STR14## C.sub.3 H.sub.12 NO.sub.3 P hygroscopic product m.p.: 131.degree. 31% C H N P 25.53 8.51 9.93 25.71 8.76 9.98 21.96 ##STR15## C.sub.4 H.sub.14 NO.sub.3 P hygroscopic product 81% C H N P 30.97 9.03 9.03 30.94 9.03 8.94 20.10 ##STR16## C.sub.4 H.sub.14 NO.sub.3 P m.p. 177.5.degree. 99% C H N P 30.97 9.03 1.03 30.97 9.17 8.96 19.94 ##STR17## C.sub.3 H.sub.10 NO.sub.3 P hygroscopic product 80% C H N P 25.90 7.19 10.07 25.83 7.30 10.10 22.22 ##STR18## C.sub.3 H.sub.8 NO.sub.3 P m.p. 69.degree. C soluble 74% C H N P 26.20 5.84 10.20 26.26 5.84 10.24 22.53 ##STR19## C.sub.6 H.sub.16 NO.sub.3 P m.p. 204.degree. C 100% C H N P 39.78 8.84 7.74 39.79 9.14 7.61 17.20 ##STR20## C.sub.6 H.sub.10 NO.sub.3 P m.p. 148.degree. C soluble 90% C H N P 41.0 5.7 17.7 41.19 5.78 17.69 8.09 ##STR21## C.sub.7 H.sub.12 NO.sub.3 P m.p. 153.degree. C 41% C H N P 44.4 6.3 7.4 16.4 44.48 6.39 7.46 16.51 ##STR22## C.sub.6 H.sub.16 NO.sub.3 P m.p. 94.degree. C 78% C H N P 32.80 7.65 7.65 33.29 7.86 7.26 15.39__________________________________________________________________________ table 1A__________________________________________________________________________ ##STR23## Empirical Physical Centesimal analysisB M formula characteristics % calculated found Remarks__________________________________________________________________________ ##STR24## Na C.sub.4 H.sub.10 NaO.sub.3 P white hygroscopic, soluble solid C H Na P 30.00 6.25 14.38 19.38 29.84 6.29 14.29 19.22 ##STR25## Na C.sub.4 H.sub.10 NaO.sub.3 P white hygroscopic, soluble solid C H Na P 30.00 6.25 14.38 19.38 29.84 6.30 14.13 19.37CH.sub.3 OCH.sub.2CH.sub.2 Na C.sub.3 H.sub.8 NaO.sub.4 P white hygroscopic, C 22.22 22.16 soluble solid H 4.94 5.05 Na 14.20 14.16 P 19.14 19.20CH.sub.3CH.sub.2 K C.sub.2 H.sub.6 KO.sub.3 P m.p.: 139.degree. C C 16.4 16.3 Reaction with soluble H 4.05 4.11 potash in hydro- K 26.4 26.31 alcoholic solution P 20.9 20.86 at 45.degree. C__________________________________________________________________________

ii- substituted ammonium salts

(a) Alkanol amine and alkyl amine salts

Preparation of monoethanol ammonium O-ethyl phosphite

0.05 mole of O,O-diethyl phosphite is poured into an aqueous solution of one equivalent of monoethanolamine. The reaction is carried out for 1 hour at 50.degree. C. Removal of the water by evaporation leaves a water-soluble oil.

Yield: 35%, n.sub.D.sup.20 : 1.4595. ______________________________________Analysis for C.sub.4 H.sub.14 NO.sub.4 P% C H N P______________________________________Calculated 28.1 8.2 8.2 18.1Found 28.16 8.2 8.1 18.22______________________________________

Similar compounds, whose characteristics are shown in the following Table 2, were prepared by the same process. The yields are in excess of 85% in every case.

Table 2__________________________________________________________________________ ##STR26## R ##STR27## Empirical formula Physical characteristics Centesimal analysis %calculatedfound Remarks__________________________________________________________________________ ##STR28## H.sub.3 NCH.sub.3 CH.sub.2 CH.sub.2 OH C.sub.5 H.sub.16 NO.sub.4 P oil n.sub.D.sup.20 = 1.4535 soluble C H N P 32.4 32.20 9.16 7.44 16.56 heating under reflux for 30 mins in aceto- nitrileCH.sub.3CH.sub.2 H.sub.2 N(CH.sub.2CH.sub.2 OH).sub.2 C.sub.6 H.sub.18 NO.sub.5 P oil C 33.5 33.23 heating under n.sub.D.sup.20 = 1.4715 H 8.38 8.29 reflux for 30 N 6.83 6.70 mins in water P 14.4 14.27 ##STR29## H.sub.2 N(CH.sub.2 CH.sub.2 OH).sub.2 C.sub.7 H.sub.20 NO.sub.5 P oil n.sub.D.sup.20 = 1.4675 soluble C H N P 36.7 34.16 9.03 5.63 12.39 heating under reflux for 1.5 hours in waterCH.sub.3 CH.sub.2 HN(CH.sub.2 CH.sub.2 OH).sub.3 C.sub.8 H.sub.22 NO.sub.6 P m.p.: 50.degree. C C 37.1 37.19 heating under soluble H 8.5 8.30 reflux for 1 N 5.4 5.3 hour in water P 11.95 12.16 ##STR30## HN(CH.sub.2 CH.sub.2 OH).sub.3 C.sub.9 H.sub.24 NO.sub.6 P m.p.: 40.degree. C C H N P 39.58 8.8 5.12 11.3 39.81 8.98 5.30 11.11 heating under reflux for 1.5 hours in waterC.sub.2 H.sub.5 ##STR31## C.sub.8 H.sub.14 NO.sub.3 P m.p.: 62.degree. C soluble C H N P 43.7 47.26 7.05 6.96 15.32 heating under reflux for 30 mins in water recrystallizatio n from acetoneisoC.sub.3 H.sub.7 ##STR32## C.sub.9 H.sub.16 NO.sub.3 P m.p.: 88.degree. C soluble C H N P 49.7 49.9 7.06 6.36 14.36 heating under reflux for 4 hours in water recrystallizati on from tolueneCH.sub.3CH.sub.2 NH.sub.2 (CH.sub.3).sub.2 C.sub.4 H.sub.14 NO.sub.3 P oil C 34.58 34.58 heating to n.sub.D.sup.20 : 1.4295 H 10.08 10.1 60.degree. C for 1 hour soluble N 10.08 10.06 P 22.3 21.95__________________________________________________________________________

another method or preparing alkyl ammonium salts comprises reacting an ammonium halide with a dialkyl phosphite in accordance with the following scheme: ##STR33## (cf. Orlovskii et. al, J. Organ. Chem. USSR, 1972, Vol. 42, pages 1924-27).

The following compounds were prepared by this method:

monoethyl ammonium O-ethyl phosphite diethyl ammonium O-ethyl phosphite triethyl ammonium O-ethyl phosphite

(b) Quaternary ammonium salts

Preparation of tetramethyl ammonium O-methyl phosphite

0.05 mole of O,O-dimethyl phosphite is added to an equivalent quantity of trimethyl amine in solution in acetone. The reaction medium is kept at 50.degree. to 60.degree. C. for 2 hours. Evaporation of the acetone leaves a highly hygroscopic water-soluble solid.

Yield: 77%. ______________________________________Analysis for C.sub.5 H.sub.16 NO.sub.3 P% C H N P______________________________________Calculated 35.5 9.47 8.28 18.35Found 35.5 9.22 8.22 18.48______________________________________

The corresponding O-ethyl and O-isopropyl derivatives were obtained by the same method, the O,O-dimethyl phosphite being replaced by the O-methyl-O-ethyl and the O-methyl-O-isopropyl phosphite, respectively. The reaction is carried out at 70.degree. to 100.degree. C. in acetonitrile. The solids obtained are recrystallized from acetone.

Tetramethyl ammonium O-ethyl phosphite

Yield: 94%; m.p.: 134.degree. C. ______________________________________Analysis for C.sub.5 H.sub.18 NO.sub.3 P% C H N P______________________________________Calculated 39.4 9.84 7.65 16.95Found 39.38 9.40 7.80 16.90______________________________________

Tetramethyl ammonium O-isopropyl phosphite

Yield: 92%; m.p.: 153.degree. C. ______________________________________Analysis for C.sub.7 H.sub.20 NO.sub.3 P% C H N P______________________________________Calculated 42.6 10.15 7.11 15.7Found 42.8 10.26 7.13 15.9______________________________________

III- Divalent metal salts

A metal halide is reacted with a dialkyl phosphite in accordance with the following scheme: ##STR34## (cf. Orlovskii et. al, J. Organ. Chem. USSR, Vol. 42, pages 1924-1972).

Calcium O-ethyl phosphite was prepared in this way.

A mixture of 11 g (0.01 mole) of calcium chloride with 2.8 g (0.02 mole) of O,O-diethyl phosphite is heated with stirring for 2 hours to 110.degree.-130.degree. C. The mixture is then cooled. A precipitate is obtained which, after filtration and washing, gives white crystals melting at above 420.degree. C. in a yield of 96%.

______________________________________Analysis for C.sub.4 H.sub.12 O.sub.6 P.sub.2 Ca% C H______________________________________Calculated 18.6 1.5Found 19.12 1.98______________________________________

The following salts may be similarly obtained by replacing the starting salt:

barium O-ethyl phosphite zinc O-ethyl phosphite

Magnesium O-ethyl phosphite

0.2 mole of O,O-diethyl phosphite is added to a suspension of 0.1 mole of magnesia in 100 cc of distilled water. The exothermic reaction is carried out with stirring for 2 hours at 50.degree. C. After filtration, the water is evaporated from the filtrate, leaving a white solid which is washed with acetone and then dried.

Yield: 100%, m.p.:> 300.degree. C. ______________________________________Analysis for C.sub.4 H.sub.12 MgO.sub.6 P.sub.2% C H Mg P______________________________________Calculated 19.83 4.96 10.02 25.63Found 19.90 5.22 9.96 25.60______________________________________

The following Table 3 shows the characteristics (appearance, melting point, solubility in water) and analysis of other metal alkyl phosphites obtained in the same way as in the preceding Example. Unless otherwise indicated, the yields are in excess of 70%, the majority being quantitative. In the case of manganese salts, the metal oxide is replaced by a carbonate.

Table 3__________________________________________________________________________ ##STR35## Physical Centesimal analysisR M Empirical formula characteristics % calculated found Remarks__________________________________________________________________________ white solid C 23.52 23.50CH.sub.3CH.sub.2CH.sub.2 Mg C.sub.6 H.sub.16 MgO.sub.6 P.sub.2,2H.sub.2 O F > 300.degree. C H 6.55 6.36 soluble Mg 7.85 7.93 P 20.30 20.27 ##STR36## Mg C.sub.6 H.sub.16 MgO.sub.6 P.sub.2,2H.sub.2 O white solid F = 126.degree. C C H Mg P 26.62 5.92 8.9 22.9 26.6 5.9 9.1 22.8 analysis ex- pressed in dry weight reaction temperature 90.degree. CCH.sub.3 (CH.sub.2).sub.3 Mg C.sub.8 H.sub.20 MgO.sub. 6 P.sub.2,2H.sub.2 O white solid C 28.74 28.70 soluble H 7.20 7.13 Mg 7.20 7.37 P 18.56 18.56 ##STR37## Mg C.sub.8 H.sub.20 MgO.sub.6 P.sub.2 white solid soluble C H Mg P 32.21 6.71 8.05 20.81 31.99 6.94 7.98 20.66 ##STR38## Mg C.sub.8 H.sub.20 MgO.sub.6 P.sub.2,H.sub.2 O white solid soluble C H Mg P 28.74 7.20 7.20 18.56 28.63 7.16 7.29 18.70CH.sub.3 OCH.sub.2 CH.sub.2 Mg C.sub.6 H.sub.16 MgO.sub.8 P.sub.2 white solid C 23.84 23.76 soluble H 5.30 5.30 Mg 7.95 7.98 P 20.53 20.40CH.sub.3CH.sub.2CH.sub.2 Ca C.sub.6 H.sub.16 CaO.sub.6 P.sub.2 white solid C 25.17 24.96 soluble H 5.59 5.90 Ca 13.99 13.74 P 21.68 21.56 ##STR39## Ca C.sub.6 H.sub.16 CaO.sub.6 P.sub.2 white solid F > 300.degree. C C H Ca P 25.17 5.59 13.99 21.68 25.06 6.10 13.87 21.63 Reaction temperature 60-70.deg ree. CCH.sub.3(CH.sub.2).sub.3 Ca C.sub.8 M.sub.20 CaO.sub.6 P.sub.2 white solid C 30.57 30.79 soluble H 6.37 6.29 Ca 12.74 12.69 P 19.75 19.60 ##STR40## Ca C.sub.8 H.sub.20 CaO.sub.6 P.sub.2 white solid soluble C H Ca P 30.57 6.37 12.74 19.75 30.66 6.16 12.74 19.74 ##STR41## Ca C.sub.8 H.sub.20 CaO.sub.6 P.sub.2 white solid soluble C H Ca P 30.57 6.37 12.74 19.75 30.60 6.43 12.90 19.59CH.sub.3 OCH.sub.2 CH.sub.2 Ca C.sub.6 H.sub.16 CaO.sub.8 P.sub.2 white solid C 22.64 22.63 soluble H 5.03 5.16 Ca 12.58 12.57 P 19.50 18.98 ##STR42## Ca C.sub.16 H.sub.36 CaO.sub.6 P.sub.2,1,5H.sub.2 O white solid substantially insoluble C H Ca P 42.40 8.60 13.68 8.83 42.40 8.06 12.50 8.03 Yield 25%CH.sub.3CH.sub.2 Mn C.sub.4 H.sub.12 MnO.sub.6 P.sub.2 white solid C 17.6 17.4 heating under F = 136.degree. C H 4.4 4.3 reflux soluble Mn 20.1 19.9 reflux P 22.7 22.7CH.sub.3CH.sub.2CH.sub.2 Mn C.sub.6 H.sub.16 MnO.sub.6 P.sub.2 white solid C 23.92 23.79 heating under soluble H 5.31 5.37 reflux Mn 18.27 18.19 P 20.59 20.57 ##STR43## Mn C.sub.6 H.sub.16 MnO.sub.6 P.sub.2,2H.sub.2 O white solid soluble C H Mn P 21.59 5.94 16.32 18.40 21.50 5.60 16.50 18.32CH.sub.3 (CH.sub.2).sub.3 Mn C.sub.8 H.sub.20 MnO.sub.6 P.sub.2 pale pink solid, C 29.17 29.56 soluble H 6.08 5.76 Mn 16.71 16.79 P 18.84 18.80 ##STR44## Mn C.sub.8 H.sub.20 MnO.sub.6 P.sub.2,H.sub.2 O pale pink solid, soluble C H Mn P 27.70 6.34 15.85 17.88 27.76 6.12 15.72 17.78 Yield 55%CH.sub. 3 CH.sub.2 CH.sub.2 Zn C.sub.6 H.sub.16 O.sub.6 P.sub.2 Zn highly viscous C 23.30 23.01 liquid, soluble H 5.17 5.16 Zn 21.03 21.20 P 20.06 20.16 ##STR45## Zn C.sub.6 H.sub.16 O.sub.6 P.sub.2 Zn highly viscous liquid, soluble C H Zn P 23.30 5.17 21.03 20.06 23.16 5.06 21.19 20.03__________________________________________________________________________

iv- salts obtained by a double-exchange reaction

(a) Synthesis via the barium salt

Zinc O-n-butyl phosphite

0.05 mole of O-n-butyl phosphite and 0.05 mole of baryta are dissolved in 150 cc of distilled water. The barium O-n-butyl phosphite is precipitated. A solution of 0.05 mole of zinc sulphate heptahydrate in 20 cc of distilled water is then added, as a result of which the barium sulphate is precipitated. It is separated by filtration or centrifuging. The clear filtrate is evaporated to dryness, giving a highly viscous liquid which is dried in vacuo. This liquid is soluble in water.

Yield: 82%. ______________________________________Analysis for C.sub.8 H.sub.20 O.sub.6 P.sub.2 Zn% C H Zn P______________________________________Calculated 28.31 5.89 19.17 18.28Found 28.16 5.96 19.46 18.28______________________________________

The products whose characteristics are set out in the following Table 4 were obtained by changing either the alkyl radical or the metal in the procedure described above. Unless otherwise indicated, the yields are in excess of 70%.

Table 4__________________________________________________________________________ ##STR46## Empirical Physical Centesimal analysisR M formula Characteristics % calculated found Remarks__________________________________________________________________________ ##STR47## Zn.sup. ++ C.sub.8 H.sub.20 O.sub.6 P.sub.2 Zn highly viscous liquid, soluble C H Zn P 28.31 28.16 5.95 19.54 18.06 ##STR48## Zn.sup. ++ C.sub.8 H.sub.20 O.sub.6 P.sub.2 Zn highly viscous liquid, soluble C H Zn P 28.31 28.12 6.03 19.54 18.19 ##STR49## Mn.sup.++ C.sub.8 H.sub.20 MnO.sub.6 P.sub.2 pale pink solid, soluble C H Mn P 29.17 28.99 6.11 17.11 18.74CH.sub.3 OCH.sub.2 CH.sub.2 Mn.sup. ++ C.sub.6 H.sub.16 MnO.sub. 6 P.sub.2 solid C soluble H Mn PCH.sub.3 OCH.sub.2 CH.sub.2 Zn.sup.++ C.sub.6 H.sub.16 ZnO.sub.6 P.sub.2 solid C soluble H Zn PCH.sub.3 OCH.sub. 2 CH.sub.2 Al.sup.+++ C.sub.9 H.sub.24 Al O.sub.9 P.sub.3 solid C soluble H Al PCH.sub.3 OCH.sub.2 CH.sub.2 Fe.sup.++ C.sub.6 H.sub.16 FeO.sub.6 P.sub.2 solid C soluble H Fe PCH.sub.3 CH.sub.2 Cu.sup.++ C.sub.4 H.sub.12 CuO.sub.6 P.sub.2 m.p. > 300.degree. C C 17.05 17.08 H 4.26 4.30 Cu 22.55 21.80 P 22.0 21.32__________________________________________________________________________

(b) From the sodium salt

Aluminium O-isopropyl phosphite

Sodium O-isopropyl phosphite is prepared. A solution of 0.06 mole of aluminum nitrate with nine molecules of water in 30 cc of distilled water is added to a solution of 0.18 mole of compound in 150 cc of distilled water. The aluminum O-n-propyl phosphite is precipitated. The precipitate is centrifuged, washed with water and then with acetone and finally dried in vacuo, giving a white solid which is insoluble in water.

Yield: 60%, m.p.:> 300.degree. C. ______________________________________Analysis for C.sub.9 H.sub.24 Al O.sub. P.sub.3% C H Al P______________________________________Calculated 27.27 6.06 6.82 23.48Found 27.19 6.28 6.90 23.50______________________________________

The following compounds were prepared by the same method from analogous/sodium O-alkyl phosphite derivatives. The iron(III)salts were obtained by replacing the aluminum nitrate with ferric iron nitrate.

The characteristics of all these compounds are set out in the following Table 5. Unless otherwise indicated, the yields are in excess of 70%.

Table 5__________________________________________________________________________ ##STR50## Physical Centesimal analysisR M.sup. +++ Empirical formula characteristics % calculated found Remarks__________________________________________________________________________CH.sub.3CH.sub.2CH.sub.2 Al.sup.+++ C.sub.9 H.sub.24 AlO.sub.9 P.sub.3 white solid C m.p. > 300.degree. C H insoluble Al PCH.sub.3 (CH.sub.2).sub.3 Al.sup.+++ C.sub.12 H.sub.30 AlO.sub. 9 P.sub.5 white solid C 32.88 32.69 m.p. > 300.degree. C H 6.85 6.34 insoluble Al 6.16 6.18 P 21.23 20.99 ##STR51## Al.sup.+++ C.sub.12 H.sub.30 AlO.sub.9 P.sub.3 white solid m.p. > 300.degree. C insoluble C H Al P 32.88 32.76 6.98 6.19 21.19 ##STR52## Al.sup.+++ C.sub.12 H.sub.30 AlO.sub.9 P.sub.3 white solid m.p. > 300.degree. C insoluble C 32.88 32.73 6.94 6.14 21.24CH.sub.3CH.sub.2 Al.sup.+++ C.sub.6 H.sub.18 AlO.sub.9 P.sub.3 white solid C 20.3 20.41 m.p. > 300.degree. C H 5.09 5.09 insoluble Al 7.6 7.64 P 26.3 26.24 ##STR53## Physical Centesimal analysisR M.sup.+ Empirical formula characteristics % calculated found Remarks__________________________________________________________________________CH.sub.3CH.sub.2 Ni.sup.++ C.sub.4 H.sub.12 NiO.sub.6 P.sub.2 m.p. > 300.degree. C C 17.3 15.29 action of H 4.3 4.63 nickel bromide Ni 27.10 21.2 on sodium ethyl P 22.4 17.87 phosphate in absolute alcohol the product contains 11% of NiBr.sub.2CH.sub.3CH.sub.2CH.sub.2 Fe.sup.+++ C.sub.9 H.sub.24 FeO.sub.9 P.sub.3 white solid C 25.41 25.36 m.p. > 300.degree. C H 5.64 5.92 insoluble Fe 13.17 13.16 P 21.88 21.88 ##STR54## Fe.sup.+++ C.sub.9 H.sub.24 FeO.sub.9 P.sub.3 white solid m.p. > 300.degree. C insoluble C 25.41 25.24 5.46 13.30 21.88CH.sub.3(CH.sub.2).sub.3 Fe.sup.+++ C.sub.12 H.sub.30 FeO.sub.9 P.sub.3 white solid C 30.83 30.90 m.p. > 300.degree. C H 6.42 6.10 insoluble Fe 11.99 12.10 P 19.91 19.88 ##STR55## Physical Centesimal analysisR M.sup.n.spsp.+ Empirical formula characteristics % calculated found Remarks__________________________________________________________________________ ##STR56## Fe.sup.+++ C.sub.12 H.sub.30 FeO.sub.9 P.sub.3 white solid m.p. > 300.degree. C C H Fe P 30.83 30.90 6.13 11.98 19.99 ##STR57## Fe.sup.+++ C.sub.12 H.sub.30 FeO.sub.9 P.sub.3 white solid m.p. > 300.degree. C insoluble C H Fe P 30.83 30.94 6.12 12.08__________________________________________________________________________ 20.01

v - iron salts

Iron O-ethyl phosphite

This compound is prepared by the method (Chem. Ber. 90, page 811) comprising reacting ferric chloride with 3 equivalents of ethyl phosphorous acid. A solid melting above 300.degree. C. is obtained after filtration and washing.

______________________________________Analysis for C.sub.6 H.sub.16 Fe O.sub.9 P.sub.3% C H Fe P______________________________________Calculated 18.80 4.70 14.60 24.3Found 18.90 3.80 14.63 24.2______________________________________

Iron O-(2-chloroethyl)-phosphite

This compound is prepared by ORLOVSKI'S method described above, replacing the soda with ferric chloride. It is possible to obtain the iron salts of the phosphites such as, for example, iron O-(2-chloroethyl)-phosphite which decomposes at around 135.degree. C.

______________________________________Analysis for C.sub.6 H.sub.5 Cl.sub.3 Fe O.sub.9 P.sub.3% C H N P______________________________________Calculated 14.8 3.04 21.9 19.1Found 14.78 3.019 21.77 18.78______________________________________

The following Examples illustrate the fungicidal properties of the following compounds:

1 - ammonium O-methyl phosphite 2 - ammonium O-ethyl phosphite 3 - sodium O-ethyl phosphite 4 - calcium O-ethyl phosphite 5 - ammonium O-n-propyl phosphite 6 - ammonium O-isopropyl phosphite 7 - ammonium O-n-butyl phosphite 8 - ammonium O-n-hexyl phosphite 9 - ammonium O-[(2-ethyl)-n-hexyl] phosphite 10 - sodium O-n-octyl phosphite 11 - sodium O-n-dodecyl phosphite 12- sodium O-n-hexadecyl phosphite 13- ammonium O-allyl phosphite 14- ammonium O-methoxy ethyl phosphite 15- ammonium O-cyclohexyl phosphite 16- ammonium O-benzyl phosphite 17- ammonium O-tetrahydrofurfuryl phosphite 18- sodium O-methyl phosphite 19- tetramethyl ammonium O-methyl phosphite 20- dicyclohexyl ammonium O-methyl phosphite 21- potassium O-ethyl phosphite 22- magnesium O-ethyl phosphite 23- barium O-ethyl phosphite 24- zinc O-ethyl phosphite 25- manganese O-ethyl phosphite 26- aluminum O-ethyl phosphite 27- iron(III) O-ethyl phosphite 28- copper(II) O-ethyl phosphite 29- nickel(II) O-ethyl phosphite 30- magnesium O-n-propyl phosphite 31- sodium O-isopropyl phosphite 32- calcium O-isopropyl phosphite 33- aluminum O-isopropyl phosphite 34- sodium O-n-butyl phosphite 35- calcium O-n-butyl phosphite 36- ammonium O-sec.-butyl phosphite 37- aluminum O-sec.-butyl phosphite 38- calcium O-n-[(2-ethyl)-n-hexyl] phosphite 39- sodium O-methoxy ethyl phosphite 40- magnesium O-methoxy ethyl phosphite 41- ammonium O-propargyl phosphite 42- ammonium O-phenyl phosphite

EXAMPLE 1: In vivo test on Plasmopara viticola in vine plants

(a) Preventive treatment

The leaves of pot-grown vine plants (Gamay variety) are sprayed underneath using a spray gun with an aqueous suspension of a wettable powder having the following composition (by weight):

______________________________________ active material to be tested 20%deflocculant (calcium lignosulphate) 5%wetting agent (sodium alkyl aryl sulphonate) 1%filler (aluminum silicate) 74%______________________________________ in the required dilution containing the active material to be tested in the required dose. Each test was repeated three times.

After 48 hours, the plants are contaminated by spraying the leaves underneath with cc of an aqueous suspension of approximately 80,000 units/cc of spores of the fungus.

The pots are then placed in an incubation cell at 20.degree. C./100% relative humidity for a period of 48 hours.

The plants are inspected 9 days after infestation.

Under these conditions, it is found that, in a dose of 0.5 g/l, compounds 1 to 9, 11 to 22, 24, 26 to 30, 32 to 38 and 40 to 42 afford total protection, whilst compounds 23, 25, 31 and 39 afford good protection.

In addition, it was found that none of the compounds tested showed the least phytotoxicity.

(b) Treatment after contamination

The procedure is as described in (a) above, except that the plants are first of all contaminated and then treated with the active material to be tested, the plants being inspected 9 days after contamination.

Under these conditions, it was found that, in a dose of 1 g/l, compounds 1 to 8, 10 to 29, 31, 32, 36 and 40 to 42 completely stop the development of mildew on the vine plants.

(c) Systemic test by root absorption

Several vine stocks (Gamay variety) each accommodated in a pot containing vermiculite and a nutritive solution are sprinkled with 40 cc of a solution containing 0.5 g/l of the material to be tested. After 2 days, the vine is contaminated with an aqueous suspension containing 100,000 spores/cc of Plasmopara viticola. The spores are then left to incubate for 48 hours in a room at 20.degree. C./100% relative humidity. The degree of infestation is assessed after about 9 days in relation to an infested control which has been sprinkled with 40 cc of distilled water.

Under these conditions, it was found that, in this dose of 0.5 g/l, compounds 1 to 18, 20 to 35 and 37 to 42, absorbed by the roots, afford total protection to the vine leaves against mildew, which demonstrates clearly the systemic nature of these compounds.

EXAMPLE 2: Open-air test on mildew of the vine

Groups of 5 vine stocks (Gamay variety) are sprayed every 8 days from the 5th July to the 20th August with an aqueous solution containing 200 g/hl of active material or, in one case, a wettable powder of the following composition (by weight)

______________________________________ active material (compound) 50%calcium lignosulphate (deflocculant) 5%sodium alkyl aryl sulphonate 1%anti-lumping silica 5%kaolin (filler) 39%______________________________________

The mildew (Plasmopara viticola) appears from 24th July onwards. Natural contamination is considerable. In August the stocks are sprayed in such a way that the leaves are kept permanently wet. The attacks of fungus are considerable and, in September, the mildew is promoted by particularly wet weather.

At the end of October, the number of mildewed areas per plot is counted on the leaves which have been effectively treated.

Under these conditions, it was found that the controls show 136 mildewed areas per plot, whereas the plots treated with compounds numbers 2, 3, 4, 21, 22, 26, 31 and 39 do not show the least sign of mildew.

In addition, the shoots which were not present during the treatments show only a few mildewed areas per plot, which adequately confirms the systemic character of these compounds under glass.

EXAMPLE 3: Test on tobacco

Groups of 5 tobacco plants (PB 91) are treated on the 15th June with a wettable powder containing 160 g/l of manebe (80%), 300 g/l of sodium O-ethyl phosphite and 300 g/l of magnesium O-ethyl phosphite (50%). One group is left untreated as control.

After 48 hours, the plants are artificially contaminated (with Peronospora tabacina) and then finely sprayed with water. The treatment is then continued once weekly.

An inspection is made on the 12th August by counting the number of mildewed areas per group. The results are set out in the following Table 6:

Table 6______________________________________ Number of mildewed areas PRODUCT per group______________________________________Control 48Manebe 4Sodium O-ethyl phosphite 2Magnesium O-ethyl phosphite 1______________________________________

Other tests show that the two compounds according to the invention are also effective against this fungus in curative treatment, and have a systemic action.

EXAMPLE 4: Avocado test

Your avocado plants (variety Persea indica) are planted in soil infested with Phytophtora cinnamomi, after which the soil is sprayed with a solution containing 3 g/l of aluminium O-ethyl phosphite. Some plants are left untreated as controls. Under these conditions, it was found after 20 days that the roots of the control plants are completely destroyed, whilst 90% of the roots of the treated plants are healthy.

EXAMPLE 5: Pineapple test

Young pineapple plants are contaminated with Phytophtora parasitica, and then treated after 48 hours by spraying with a solution containing 0.5 g/l of calcium O-ethyl phosphite. It was found after 30 days that the fungus was completely inhibited in the treated plants, whilst the controls are infested.

EXAMPLE 6: Strawberry test

Ten strawberry plants (variety Surprise des Halles) are treated by soaking for 1 hour in an aqueous solution containing 0.2% of calcium O-isopropyl phosphite, dried and then planted out, on the 14th June, in soil artificially contaminated with Phytophtora cactorum. Immediately afterwards and then once every 8 days until the 18th July, the plants are sprayed with the same solution which corresponds to a total application of 0.5 g of active material per plant.

Plants treated by soaking and spraying with water are used as controls.

Under these conditions, it was found on the 24th July that the protection afforded to the strawberry plants is complete, whilst 76% of the control plants are dead.

EXAMPLE 7: Pimento Test

10 pimento plants (variety Yolo wonder) which have already been planted out are transplanted on the 27th June to pots of earth artificially contaminated with Phytophtora capsici. The plants are sprayed immediately and then once every 8 days until the 18th July with an aqueous solution containing zinc O-ethyl phosphite so as to apply a total of 0.5 g of treatment per plant.

Plants sprayed with water are used as controls.

Under these conditions, it was found that the 10 plants are intact at the end of August, whilst the control plants have all died by 25th July.

All these Examples clearly show the remarkable fungicidal activity of the compounds according to the invention, on the one hand a systemic anti-mildew activity which both prevents and stops the development of vine mildew, and on the other hand on certain phytophtora as well.

However, they have also been found to be extremely effective in controlling other types of parasitic fungi such as Guignardia bidwellii in vine, Pseudoperonospora humuli, Bremia lactucae, Phytophthora infestans, Peronospora sp., Phytophtora palmivora, Phytophtora phaseoli, Phytophtora megasperma, Phytophtora drechsteri and other Phytophtora sp. in temperature-climate or tropical-climate plants such as tobacco, market-gardening cultures, especially onion, sweet pepper, tomato, bean, in ornamental plants, in soya, citrus, cocoa, coconut palm, hevea rubber.

Accordingly, the compounds according to the invention are particular suitable for use in the preventive or curative treatment of fungus disease in plants, especially fungus disease caused by phycomycetes and ascomycetes in the vegetables already mentioned, but also more generally in agriculture, arboriculture, horticulture, market gardening, but more especially in viticulture.

The compounds according to the invention may be used with advantage in admixture with one another or with other known fungicides, such as metal dithiocarbamates (manebe, zinebe, mancozebe,) basic salts or hydroxides of copper (oxychloride, oxysulphate), (tetrahydro)phthalimides (captane, captafol, folpel), N-(1-butyl carbamoyl)-2-benzimidazole, methyl carbamate (benomyl), 1,2-di-(3-methoxy or ethoxy)carbonyl-2-thioureido benzenes (thiophanates), methyl 2-benzimidazole carbamate, etc., either to complete the range of activity of the compounds according to the invention or to increase their persistence.

It has also been found that the compounds according to the invention may be mixed with other fungicidal, anti-mildew phosphorus derivatives, especially 2-hydroxy-1,3,2-dioxaphospholanes, .beta.-hydroxy ethyl phosphites and phosphorous acid and its salts.

The doses in which the compounds according to the invention are used may vary within wide limits, depending both upon the virulence of the fungus and upon the climatic conditions. Doses of from 0.01 to 5 g/l of active material are generally suitable.

For their practical application, the compounds according to the invention are rarely used on their own. Instead, they generally form part of formulations which, as a rule, contain a support and/or a surfactant in addition to the active material according to the invention.

In the context of the invention, a support is an organic or mineral, natural or synthetic material with which the active material is associated to facilitate its application to the plant, to seeds or to soil, or its transportation or handling. The support can be solid (clays, natural or synthetic silicates, resins, waxes, solid fertilizers) or fluid (water, alcohols, ketones, petroleum fractions, chlorinated hydrocarbons, liquefied gases).

The surfactant can be an ionic or non-ionic emulsifier, dispersant or wetting agent such as, for example, salts of polyacrylic acids and lignin-sulphonic acids, condensates of ethylene oxide with fatty alcohols, fatty acids or fatty amines.

The compositions according to the invention can be prepared in the form of wettable powders, soluble powders, dusting powders, granulates, solutions, emulsifiable concentrates, emulsions, suspended concentrates and aerosols.

The wettable powders according to the invention can be prepared in such a way that they contain from 20 to 95% by weight of the active material, and they normally contain, in addition to a solid support, from 0 to 5% by weight of a wetting agent, from 3 to 10% by weight of a dispersant and, when necessary, from 0 to 10% by weight of one or more stabilizers and/or other additives, such as penetration agents, adhesives or anti-lumping agents, colorants . . . etc.

One example of the composition of a wettable powder is given below:

______________________________________ active material 50%calcium lignosulphate (deflocculant) 5%anionic wetting agent 1%antilumping silcia 5%kaolin (filler) 39%______________________________________

Powders soluble in water are obtained by mixing from 20 to 95% by weight of the active material, from 0 to 10% of an antilumping agent, the remainder being a hydrosoluble filler mainly a salt.

There is one example of composition of a soluble powder:

______________________________________active material 70%anionic wetting agent 0.5%antilumping silica 5%sodium sulfate (soluble filler) 24.5%______________________________________

Aqueous dispersions and emulsions, for example compositions obtained by diluting with water a wettable powder or an emulsifiable concentrate according to the invention, are included within the general scope of the invention. These emulsions can be of the water-in-oil type or of the oil-in-water type, and can have a thick consistency resembling that of a "mayonnaise".

The compositions according to the invention can contain other ingredients, for example protective colloids, adhesives or thickeners, thixotropic agents, stabilizers or sequestrants, as well as other active materials known to have pesticidal properties, especially acaricides or insecticides.

Claims

1. A fungicidal composition for controlling fungus disease in plants comprising as an active material, a fungicidally effective quantity of at least one compound of the formula ##STR58## in which R is selected from a member of the group consisting of an alkyl, halogen-substituted alkyl or nitro-substituted alkyl radical, the alkyl portion of said alkyl radicals containing from 1 to 8 carbon atoms, an alkenyl, halogen-substituted alkenyl, alkinyl, halogen-substituted alkinyl and an alkoxy-substituted alkyl radical, the hydrocarbon portion of said alkenyl, alkinyl and alkoxy-alkyl radicals containing from 2 to 5 carbon atoms,

M is selected from a member of the group consisting of an ammonium cation; ammonium substituted by a member of the group consisting of 1 to 4 alkyl or hydroxy-alkyl radicals each containing from 1 to 5 carbon atoms, 1 to 2 cyclohexyl radicals and a phenyl radical; and a cation of a metal from the group consisting of the alkali metals, alkaline earth metals, and polyvalent metals of zinc, manganese, copper (I) and (II), iron, nickel and aluminum and n is an integer equal to the valency of M in combination with an agriculturally acceptable carrier.

2. A fungicidal composition according to claim 1 which contains an inert carrier and a compatible surfactant.

3. A fungicidal composition according to claim 1 in the form of a wettable powder containing about 20 to 95% by weight of said active material, about 0 to 5% by weight of a wetting agent, from 3 to 10% by weight of a dispersant and from 0 to 10% by weight of other additives selected from the group consisting of a stabilizer, a penetration agent, an adhesive, an anti-lumping agent, a colorant and mixtures thereof, the balance being inert solid support.

4. A fungicidal composition according to claim 1 in which said composition is in the form of a soluble powder containing about 20 to 95% of said active material, 0 to 10% of an anti-lumping agent and the balance being a hydrosoluble inert solid support.

5. A fungicidal composition according to claim 1 which contains an inert solid carrier and a compatible surfactant, wherein said composition is in the form selected from a wettable powder and a soluble powder.

6. A composition as claimed in claim 1, wherein M is an ammonium cation substituted by 1 to 4 alkyl radicals or hydroxy-alkyl radicals containing from 1 to 5 carbon atoms or by 1 to 2 cyclohexyl radicals or a phenyl radical.

7. A composition as claimed in claim 1, wherein M is an alkali metal cation.

8. A composition as claimed in claim 1, wherein M is an alkaline earth metal cation.

9. A composition as claimed in claim 1, wherein M is a cation of a metal from the group comprising zinc, manganese, copper (I) and (II), iron (II) and (III) nickel and aluminum.

10. A composition as claimed in claim 1, wherein R is an alkyl radical, a halogen substituted alkyl radical containing from 1 to 4 carbon atoms, an allyl, propargyl, allyl-oxy or alkoxy-alkyl radical containing from 2 to 3 carbon atoms.

11. A composition as claimed in claim 10, wherein R is the ethyl radical.

12. A composition as claimed in claim 10, wherein R is the isopropyl radical.

13. A composition as claimed in claim 11, wherein the active material is sodium O-ethyl phosphite.

14. A composition as claimed in claim 11, wherein the active material is calcium O-ethyl phosphite.

15. A composition as claimed in claim 11, wherein the active material is aluminum O-ethyl phosphite.

16. A composition as claimed in claim 11, wherein the active material is magnesium O-ethyl phosphite.

17. A composition as claimed in claim 11, wherein the active material is zinc O-ethyl phosphite.

18. A composition as claimed in claim 11, wherein the active material is cuprous O-ethyl phosphite.

19. A composition as claimed in claim 11, wherein the active material is cupric O-ethyl phosphite.

20. A composition as claimed in claim 12, wherein the active material is sodium O-isopropyl phosphite.

21. A composition as claimed in claim 12, wherein the active material is calcium O-isopropyl phosphite.

22. A composition as claimed in claim 12, wherein the active material is aluminum O-isopropyl phosphonate.

23. A composition as claimed in claim 12, wherein the active material is magnesium O-isopropyl phosphite.

24. A composition as claimed in claim 12, wherein the active material is zinc O-isopropyl phosphite.

25. A composition as claimed in claim 12, wherein the active material is cuprous O-isopropyl phosphite.

26. A composition as claimed in claim 12, wherein the active material is cupric O-isopropyl phosphite.

27. A composition as claimed in claim 1, which additionally contains a known fungicide.

28. A fungicidal composition as claimed in claim 1 wherein R is said alkyl radical containing 1-8 carbon atoms.

29. A method for controlling fungal diseases in plants which comprises applying a fungicidally effective amount of at least one compound of the formula ##STR59## in which R is selected from a member of the group consisting of an alkyl, halogen-substituted alkyl or nitro-substituted alkyl radical, the alkyl portion of said alkyl radicals containing from 1 to 8 carbon atoms, an alkenyl, halogen-substituted alkenyl, alkinyl, halogen-substituted alkinyl and an alkoxy-substituted alkyl radical, the hydrocarbon portion of said alkenyl, alkinyl and alkoxy-alkyl radicals each containing from 2 to 5 carbon atoms,

M is selected from a member of the group consisting of an ammonium cation; ammonium substituted by a member of the group consisting of 1 to 4 alkyl or hydroxy-alkyl radicals each containing from 1 to 5 carbon atoms, 1 to 2 cyclohexyl radicals, and a phenyl radical; and a cation of a metal from the group consisting of the alkali metals, alkaline earth metals, and polyvalent metals of zinc, manganese, copper (I) and (II), iron, nickel and aluminum and n is an integer equal to the valency of M.