Group IB Organometallic Chemistry XXXIII: ArAuPPh3, ArAu(CNR), (ArAu)n and Ar4Cu2Au2 compounds in which the aryl group contains 2-MeO, 2,6-(MeO)2, 2-Me2N, 2-Me2NCH2 and (S)- or (R)-2-Me2NCHMe substituents as potential ligands

Abstract

The synthesis and structural characterization by }1{H NMR and }1{}9{}7{Au Mossbauer spectroscopy as well as by chiral labelling of the built-in ligands of three different types of arylgold(I) compounds is described.}1{}9{}7{Au Mossbauer data revealed that the benzyl- and arylgold(I) triphenylphosphine complexes which bear potential coordinating substituents at an ortho position still contain linearly coordinated Au}I{ with 2c-2e gold(I)@?carbon bonds. The observation of isochronous NME resonances in (S)-2-Me{2}NCH(Me)C{6}H{4}AuPPh{3} confirms that no additional intramolecular Au@?N coordination occurs in solution. Preliminary results of an X-ray diffraction study of 2, 6-(MeO){2}C{6}H{3}AuPPh{3} are reported (R = 0.040, PAuC{1} angle 172.6}o{. Unsymmetrical AuC{1}C{2} and AuC{1}C{6} angles of 126.4 and 117.4}o{, respectively).Pure, uncomplexed arylgold(I) compounds have been isolated from the reaction of diarylgoldlithium compounds (arylaurates) with trimethyltin bromide. (S)-2-Me{2}NCHMeC{6}H{4}Au has a dimeric structure which most likely consists of two monomeric units associated by intermolecular Au@?N coordination thus forming a ten-membered chelate ring. The structure of insoluble 2-Me{2}NCH{2}C{6}H{4}Au and 2-Me{2}NC{6}H{4}Au are less clear. The former compound probably has a structure similar to (S)-2-Me{2}NCHMeC{6}H{4}Au (IS/QS values for two-coordinate Au}I{ centers). However, the strongly deviating IS and QS values of 2-Me{2}NC{6}H{4}Au indicate that a polynuclear structure for this compound similar to that proposed for 2-Me{2}NC{6}H{4}Cu cannot be excluded (a polymeric structure containing 2-Me{2}NC{6}H{4} groups which span three Au atoms by 3c-2e Au{2}C bonds and Au@?N coordination).The mixed Au/Cu cluster (2-Me{2}NCH{2}C{6}H{4}){4}Au{2}Cu{2} is accessible via the 12 reaction of (2-Me{2}NCH{2}C{6}H{4}){4}Au{2}Li{2} with CuI. Molecular weight and }1{H NMR studies point to a tetranuclear structure in solution, while mass spectrometry shows fragment ions with m/e corresponding to (2-Me{2}NCH{2}C{6}H{4}){3}Au{2}Cu{2}}+{, (2-Me{2}NCH{2}C{6}H{4}){3}Cu{2}Au}+{, (2-Me{2}NCH{2}C{6}H{4}){2}CuAu{2}}+{ and of (2-Me{2}NCH{2}C{6}H{4}){2}Au}+{.