Copper or Silver Complexes With Fluorinated Diketones and Unsaturated Ligands

This invention relates to new copper or silver complexes containing a fluorinated diketonate and unsaturated hydrocarbons as ligands. More particularly, copper or silver in the +1 formal oxidation state form complexes with fluorinated beta-diketonates and unsaturated ligands containing at least one nonaromatic unsaturation.

It is known that certain silver(I) and copper(I) salts form complexes with olefins and acetylenes. For example, cuprous chloride is known to form complexes with both ethylene and acetylene. U.S. Pat. No. 3,401,112 teaches a method of separating a mixture of hydrocarbons having differing degrees of unsaturation using a copper(I) salt of the formula CuXA where XA is an anion, X is oxygen or fluorine and A is the remainder of the anion. Examples of fluorinated anions include fluoro substituted carboxylates, fluorosulphonate, perfluoroborate, hexafluorophosphate and hexafluoroantimonate. CuXA forms a cuprous complex with said unsaturated hydrocarbon. Similarly, U.S. Pat. No. 3,517,079 describes a process for separating vinyl aromatic hydrocarbons from alkyl aromatic hydrocarbons using a cuprous fluoroborate or cuprous fluorophosphate salt wherein a complex is formed. U.S. Pat. Nos. 3,754,047 and 3,755,487 relate to a process for separating complexible ligands such as olefins, acetylenes, aromatics, CO and the like from feedstreams by contacting the feedstream with a cuprous salt including CuBF.sub.4, CuPF.sub.6 and CuOOCCF.sub.3.

It has been discovered that copper(I) and silver(I) can form a new class of complexes with fluorinated acetylacetonate anions and unsaturated hydrocarbons as ligands. The complexes of the invention have the formula ##STR2## where M is Cu(I) or Ag(I); R.sup.1 is C.sub.1 -C.sub.6 fluoroalkyl, C.sub.1 -C.sub.8 alkyl, C.sub.4 -C.sub.6 heterocycle containing O, S or N or C.sub.6 -C.sub.10 aryl; R.sup.2 is H or C.sub.1 -C.sub.6 alkyl with the proviso that R.sup.1 and R.sup.2 together with the carbons to which they are attached may be joined together to form a C.sub.6 ring; L is an unsaturated hydrocarbon ligand containing at least one non-aromatic unsaturation capable of forming a Cu-L bond, preferably an unsaturated hydrocarbon containing at least one ethylenic, acetylenic or isonitrilic unsaturation; x and y are 1 or 2; and n is an integer from 1 to 8.

The present Cu(I) complexes contain fluorinated acetylacetonate anions and unsaturated hydrocarbons as ligands. Preferred fluorinated acetylacetonate anion ligands have the formula ##STR3## where R.sup.1 is C.sub.1 -C.sub.3 fluoroalkyl, especially CF.sub.3, C.sub.1 -C.sub.6 alkyl, C.sub.6 -C.sub.10 aryl or C.sub.4 -C.sub.5 heterocycle containing O, S or N, R.sup.2 is H with the proviso that R.sup.1 and R.sup.2 may join together to form a C.sub.6 ring, and n is an integer from 1 to 4, especially 1. Examples of neutral preferred embodiments of fluorinated acetylacenates incorporated into the present complexes as anions include ##STR4##

Preferred unsaturated hydrocarbons are (a) alkenes of the formula ##STR5## where each R.sup.3 -R.sup.6 is independently H; C.sub.1 -C.sub.30, more preferably C.sub.1 -C.sub.15 and especially C.sub.1 -C.sub.8 aliphatic with the proviso that any combination of R.sup.3, R.sup.4, R.sup.5 and R.sup.6 may be joined together to form at least one C.sub.4 -C.sub.14, more preferably C.sub.5 -C.sub.12, most preferably C.sub.6 -C.sub.8 cycloaliphatic ring; --C.tbd.N; C.sub.6 -C.sub.10 aryl; C.sub.7 -C.sub.14 araliphatic; ##STR6## where m and p are 0 or 1, R.sup.7 is C.sub.1 -C.sub.20, preferably C.sub.1 -C.sub.10 aliphatic, and R.sup.8 is H, C.sub.1 -C.sub.10 aliphatic or C.sub.6 -C.sub.10 aryl with the proviso that adjacent ##STR7## may be joined together to form a C.sub.4 -C.sub.16 anhydride; (b) alkynes of the formula R.sup.9 --C.tbd.C--R.sup.10 where R.sup.9 and R.sup.10 are independently H; C.sub.1 -C.sub.30, more preferably C.sub.1 -C.sub.15 and especially C.sub.1 -C.sub.8 aliphatic; C.sub.6 -C.sub.10 aryl or C.sub.7 -C.sub.14 araliphatic; or (c) isonitriles of the formula R.sup.11 --N.tbd.C where R.sup.11 is C.sub.1 -C.sub.20 aliphatic; C.sub.3 -C.sub.10 cycloaliphatic; C.sub.7 -C.sub.20 araliphatic or C.sub.6 -C.sub.10 aryl. The unsaturated hydrocarbons may be substituted with unreactive substituents such as halogen, cyano, alkoxy, nitro, and the like.

Examples of suitable unsaturated ligands include: ethylene, acetylene, 1-octene, isobutylene, 1,5-cyclooctadiene, stilbene, diphenylacetylene, styrene, cyclooctene, 1,5,9-cyclododecatriene, 1,3-hexadiene, isopropylacetylene, 1-decene, 2,5-bicycloheptadiene, 1-octadecene, cyclopentene, octalin, methylene cyclohexane, diphenyl fulvene, 1-octadecyne, benzyl cinnamate, benzal acetophenone, acrolein, acrylonitrile, maleic anhydride, oleic acid, linolenic acid, acrylic acid, methyl methacrylate and diethyl maleate. Suitable isonitriles are, e.g., methyl isocyanide, butyl isocyanide, cyclohexyl isocyanide, phenylethyl isocyanide and phenyl isocyanide.

Examples of copper(I) and silver(I) complexes are as follows. ##STR8##

The complexes of the invention may be prepared by reacting metal oxide, fluorinated acetylacetone and unsaturated ligand in an inert organic solvent. The preparation of a cuprous complex is illustrated by the following equation: ##EQU1## Silver(I) complexes are similarly prepared. Reactants are preferably combined in approximately stoichiometric amounts. The amounts, however, are not critical and variations therefrom are possible. The reaction preferably takes place in an inert organic solvent. Preferred solvents are ethers, ketones, esters, alcohols, saturated aliphatic hydrocarbons, aromatic hydrocarbons and the like. It is necessary that the amount of CO in the reaction mixture not exceed about 10 vol%. In the above preparative reaction, CO competes with unsaturated ligand in the formation of cuprous complex and based on thermodynamic considerations, a CO complex forms in preference to the unsaturated ligand complex as long as competing amounts of CO are present. It is also desirable to carry the preparative reaction in an inert atmosphere, since gases such as oxygen may result in the oxidation of Cu(I) to Cu(II). Complexes according to the invention may also be prepared by the following reaction schemes: ##EQU2##

Reaction times are not critical. Generally, the reaction mixture is stirred until a clear solution is obtained. A solid product may then be isolated by evaporating solvent. Suitable temperatures are from about -100.degree. to +100.degree. C. with room temperature being preferred. If the reaction mixture is heated excessively, it is possible that a dissociative reaction may take place, leading to a decrease in yield. Thus, copper(I) ethylene complexes are rather unstable due to a high dissociative pressure and heating would not be desirable. On the other hand, higher molecular weight olefins result in stable compounds, and the reaction mixture can be heated without harmful results with respect to yields.

Copper(I) and silver(I) complexes according to the invention are useful in gas separation processes and as catalysts or catalyst precursors. The complexes are further illustrated in the following examples.

A suspension of 1.45 g (0.01 mole) cuprous oxide in 75 ml methylene chloride was stirred with 2.16 g (0.02 mole) of 1,5-cyclooctadiene in a 250 ml flask under nitrogen. A solution of 4.16 g (0.02 mole) 1,1,1,5,5,5-hexafluoroacetylacetone (hfacac) in 50 ml methylene chloride was added dropwise over a 30 minute period. Red Cu.sub.2 O gradually dissolved forming a clear yellow solution. The solution was filtered to remove any remaining solids and the solvent was then removed on a rotary evaporator. Cu(1,5-COD) (hfacac) was obtained as bright yellow crystals which could be purified by recrystallization from hexane. The product was characterized by IR and MNR spectroscopy and elemental analysis.

This example illustrates the preparation of complexes using CuI, a thallium salt and unsaturated ligand. To 50 ml of CH.sub.2 Cl.sub.2 was added 0.93 g CuI and 0.53 g of 1,5-cyclooctadiene (COD). After stirring for 20 minutes, 2.0 g of thallium hexafluoroacetylacetonate was added and the mixture stirred overnight. TlI was separated by filtration and the filtrate evaporated to give 1.85 g of crystalline Cu(COD) hfacac.

Using the techniques described in Example 1, other complexes were prepared as shown in the following table.