DE2237704C3 - Compounds of zero valent nickel that contain N-bonded nitriles - Google Patents

Description

Numerous nickel compounds have been described that are unsaturated by an olefin group on nickel contain bound nitriles. However, there is no literature on zero valent nickel complexes in which a nitrile is bonded to nickel through the nitrogen atom.

The present invention relates to N-linked nitrile complexes of zero valent nickel with the formula

Ni [P (OR) ₃ ] ₃ R'CN

40

wherein R stands for the 2,5-xylyl radical, 2-tolyl radical, 2,4-xylyl radical or 2-methyl-4-chlorophenyl radical and R 'represents an alkyl radical which is optionally substituted by CN with 1-10 carbon atoms or alkenyl resi with 3–10 carbon atoms, in the latter case the Carbon-carbon double bond is separated from the nitrile by at least one carbon, or an optionally F-substituted aryl radical with 6-10 carbon atoms.

The compounds with the aforementioned radicals R have an average of between 130 and 200 ° lying cone angle. The cone angle is determined according to J. Am. Chem. Soc, 92, 2956 (19/0).

Due to the sensitivity of the compounds to oxygen, the preparation of these complexes should be carried out in an inert atmosphere, such as nitrogen or argon. The compounds are most conveniently prepared by direct reaction of the nitrile with a Ni (O) -phosphorus complex NiL ₃ [L = P (OR) ₃ ] by the nitrile with the Ni (O) complex in the presence or absence of an inert Solvent, such as acetone, toluene, benzene or cyclohexane is brought into contact. Various ratios of nitrile to Ni can be used, although a ratio of 1: 1 to 20: 1 is preferred; excess nitrile can be removed under reduced pressure or in some cases by crystallization. Reaction temperatures from -75 ° C to +200 ⁰ C can be used. The temperature is not critical as the reaction is very rapid once all of the nickel (O) complex is in solution. Temperatures of -25 ° C to +50 ⁰ C is preferred to avoid thermal decomposition. Compounds other than NiL ₃ can also be suitable sources of the Ni (O), as long as undesired ligands can be removed from the reaction mixture. NiL ₄ , N ₂ NiL ₃ , (OkUn) NiL ₂ and other (NitrilJNiLg compounds are suitable. In the case of (Öle-On) NiL _2, for example, L and RCN can be added _{to (QH 1} IiNiL _{2 and} Ethylene can be removed under vacuum. In other cases, RtCN NiL ₂ compounds can be converted directly into one by reducing a Ni (II) complex, such as Ni (NO ₃ ) ₂ · 6 H ₂ O, in the presence of a large (bulky) phosphorus ligand Nitrile solvents by a reducing agent) such as NaBH ₄ , metallic Zn or AlEt ₃ .

The compounds according to the invention are suitable as catalysts in the hydrocyanation of olefinic Connections, e.g. B. in the hydrocyanation of 3-pentenenitrile or 4-pentenenitrile to adiponitrile.

Those complexes in which li'CN Acetonitrile, 3-pentenenitrile, 4-pentenenitrile, adiponitrile or methylglutaronitrile.

In DT-OS 20 05 747 a hydrocyanation process described, are used in the nickel Koniplex catalysts. This method results in the hydrocyanation of unsaturated nitriles yields, which in the most favorable case at about 25% lie.

In contrast, according to the catalysts of the present application, yields of about 30 to Over 50% obtained and that with significantly reduced response times.

The following examples illustrate the present invention.

The NMR measurements are carried out as described in »High Resolution Nuclear Magnetic Resonance Spectroscope ", J. W. E m s 1 e y, J. F e en c y and L. H. S u t c 1 i f f e, Pergamon Press (1965). The IR measurements are carried out in accordance with "Infrared Spectra of Complex Molecules", L. J. Be 11 am y, John Wiley & Sons, New York, 2nd ed. (1958).

example 1

At 0.47 g

produced according to "Inorganic Chemistry" 9, 2350 (1970) (0.4 millimoles; cone angle 14Γ) in a glass tube which was provided with a 19/22 inner ground glass connection and a magnetic stirring bar coated with "Teflon", 1 ecm CH ₃ CN ( 19 millimoles) were added. In about a minute of stirring at 25 ° C, the red solid dissolved to give a brown solution. The excess nitrile was removed under suction at a pressure of about 1 mm for a period of about 0.5 hours. The product was a brownish white solid foam which decomposed at 48-78 ° C. The IR spectrum in benzene showed

a band at 2263 cm 'due to j> _cn in the complex

(CH ₃ CN) Ni [P (O- o -QH ₄ CH ₃ U ₃

(Free CH ₃ CN in benzene absorbs at 2255 cm " ^1. ) The proton NMR spectrum in C ₆ D ₆ showed four resonances at τ 2 ^ 8,3,16,7,93 and 9.44 in the ratio of 9 : 27: 27: 3, as for ο — H of L, unseparated m- and pH of L, —CH ₃ of L and CH ₃ CN in the complex

Example 2

At 1.07 g

Ni [P (O- o- QH ₄ CH ₃ U ₃

_{1 ecm of CH 3} CN (19 millimoles) was added (1 millimole) and 3 ecm of acetone in a 25 cc Erlenmeyer flask fitted with a 19/22 internal connection and magnetic stir bar. The solid dissolved within one minute at 25 ° C. and resulted in a green-brown solution. The excess CH ₃ CN was removed in vacuo to give a fluffy golden solid. The IR spectrum was identical to that of the product from Example 1. The elemental analysis corresponded to the composition

(CH ₃ CN) Ni [P (Oo-QH ₄ CH ₃ ) ₃ ] ₃

Q ₅ H ₆₆ NNiO ₉ P ,:

Calculated ... C 67.5, H 5.8, N 1.2, Ni 5.1; found .... C 66.0, H 5.8, N 1.2, Ni 4.6.

weak, broad resonances due to (OlefinJ-Nil ^ complexes found at about -137 ppm

Example 14

To 0.045 g of bis (tris-2,5-xylylphosphite) nickel ethylene (0.05 millimoles) was added 0.02 g of tri-2,5-xylyl phosphite (0.05 µmol), 5> 1 QH ₅ CN (0.05 Millimoles) and ίο 0.25 ecm of toluene were added. The IR spectrum recorded in a 0.1 mm cell showed a band at 2208 cm " ¹ , indicating the presence of N-linked nitrile in the complex

was to be expected. (The resonance for free CH ₃ CN in QD ₆ can be found at τ 929.)

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Examples 3 to 13

The nitrile complexes shown in Table I were made into solution by the addition of 0.2 millimoles of organic 0.11 g (0.1 millimole) nitrile

Ni [P (O- o — QH ₄ CH ₃ ) :,] :,

suspended in 1.4 ecm toluene. Upon shaking, the red-orange NiLg complex dissolved and the color of the solution changed from red-orange to yellow (or orange in the case of benzonitrile), indicating a reaction with the nitrile. The ³¹ P NMR spectrum of the solution no longer showed a resonance at -128.2 ppm (85% H ₃ PO ₄ ), which is characteristic of NiL ₃ , but a new resonance in the range -130.2 to 131.3 ppm that is for an N-linked

(Nitrile) - Ni [P (O - o - QH ₄ CH ₃ ) J] ₃ complex is characteristic. In some cases (QH ₅ CN) Ni [P (O-

indicated. (Free QH ₅ CM in toluene absorbed at 2229 cm "'.) Tris-2,5-xylene phosphite has a cone angle of 144 °.

20 Examples 15-18

The nitrile complexes shown in Table 2 were dissolved in toluene by adding the organic nitrile in a 1: 1 molar ratio to the corresponding tris (triaryl phosphite) -Ni (O) complex manufactured. The IR spectra recorded in a 0.1 mm cell indicate the presence of the N-linked shown Nitrile complexes.

The following abbreviations are used in the table below:

VN = valeronitrile.

ADN = adiponitrile.

MGN = methylglutaronitrile.

4PN = 4-pentenenitrile.

T3PN = trans-3-pentenenitrile.

2M3BN = 2-methyl-3-butenenitrile.

C2M2BN = bis-2-methyl-2-butenenitrile.

T2PN = trans-2-pentenenitrile.

L = tri-o-tolyl phosphite.

Table 1

³¹ P NMR data for

(Nitrile) Ni [P (O — o — QH ₄ CH ₃ ) ;,].,

complexes formed in toluene at 26 ° C,

chemical shifts with respect to 85% H ₃ PO ₄

.15

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eispie : l nitrile (NiInI) NiL ₃ (Olefin) NiL 3 CH ₃ CN -131.0 4th VN -130.5 5 ADN -130.7 6th MGN -130.5 7th 4PN -130.4 -137.3 8th T3PN -130.8 9 2M3BN -130.2 -137.0 10 C2M2BN -130.9 11th T2PN -131.2 -136.3 12th QH ₅ CN -131.2 13th PF-QH ₄ CN -131.3

*) The chemical shift is the average of (olefin) NiL ₂ and free L in rapid exchange.

Isolated (C ₂ Hi (Ni [P (0-o-tolyl) ₃ ] ₃ ] 3 resonates at -139.7, free L at -130.0.

Table 2

Examples 15-18
IR data for (nitrile) NiL ₃ complexes in toluene

Example complex V _CN (cm ')

15 (QH ₅ CN) Ni [P (O-2,4- (CH 3) ₂ QH ₃ ) 3] 3 2213

16 (QH ₅ CN) Ni [P (OO-QH ₊ CH ₃ ) J] ₃ 2217

17 (QH ₅ CN) Ni [P (O- 2-CH ₃ -4-Cl-QH ₃ ) ₃ ] ₃ 2217

18 (CH ₃ CN) Ni [P (O-2-CH ₃ -4-Cl-QH ₃ ) ₃ ] ₃ 2261

In the above form R 'stands for optionally 3-10 carbon atoms, such as butene, pentene, hexene, Cyan-substituted alkyl radicals with 1-10 carbon atoms. Aryl radicals are those with 6-10 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, atoms, especially those which differ from benzene from hexyl, these radicals possibly also leading one, preferably. Cyano group included, also for alkenyl radicals with 20

Claims (1)

Claim: N-bonded nitrile complex of zero-valent nickel with the pomel Ni [P (OR) ₃ ] ₃ R'CN wherein R stands for the 2,5-xylyl radical, 2-tolyl radical, 2,4-xylyl radical or 2-methyl-4-chlorophenyl radical and R 'represents an alkyl radical which is optionally substituted by CN with 1-10 carbon atoms or alkenyl radical with 3-10 carbon atoms, in the latter case the carbon-carbon double bond is separated from the nitrile by at least one carbon is, or an optionally F-substituted aryl radical with 6-10 carbon atoms, stand. 20: