Gold cyano compounds

The compound 70 has also been reported showing the ambident character (both C- and N-coordination) of the cyano-stabilized ylide as ligand. The authors have also transposed their work concerning the keto-bis-ylide and palladium, with the synthesis of the C-bonded complex 71 or the new cycloplatinated or-thometallated compound 72. The latter by various treatments allows one to obtain other ylidic cationic complexes of platinum such as 73. A C,C,C-terdentate coordination of the keto bis-ylide, already observed with the palladium is also obtained from the reaction of 73 with gold derivatives. 

The majority of gold(I) carbene complexes are pure organometallic compounds and the are out of the scope of this work. Some halide or triphenylphosphine carbene complexes are known and they will be considered here. Nucleophilic addition of alcohols or amines to gold-coordinated isocyanides is one of the best-established methods to obtain gold carbene derivatives. The reaction of H[Au(CN)2] with propene oxide and estirene oxide yields (cyano)carbene complexes (380) avoiding the intermediate step.2257 A cyclic carbene compound is obtained by reaction of a dinuclear isocyanide with amine (Scheme 32).2258... 

A number of substitutions of alkylgold complexes by mercuric compounds have been examined by Gregory and Ingold44. The SE1 substitution of 1-cyano-l-carbethoxypentyl(triphenylphosphine) gold(I) has been described in Chapter 4, Section 2.3 (p. 32) and in the present section those substitutions proceeding by bimolecular mechanisms are discussed. 

An electrochemical OP sensor by the nonenzymatic route was reported based on chemical modification of the surface of a gold electrode with ferrocene derivative (Fc). For this purpose, the gold electrode was modified with dithioFc derivative to form an aminoFc-monolayer-modified electrode (Khan et al, 2007). The principle of operation of the aminoFc-modified electrode for OP sensing is that chloro-or cyano-substitued OP compounds covalently bind to aminoFc moieties, by which the redox potential of the surface-confined Fc can be altered. In fact, ca. 110 and 60 mV shifts in the redox potential were observed, suggesting a possible use of the sensors for detecting OPs from the potential shifts. 

This situation was slightly different for the cyano and the thiocyanate complexes, where the mesophase stability increased considerably compared to the halo compounds. In fact, X-ray diffraction suggested rather strong interactions between gold atoms (6.5 A), in addition to a smaller stacking period of 3.3 A, particularly for the SCN complex. Thus, the columnar structure remained basically the same, but was tighter, consistent with greater mesophase stability. 

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