Mononuclear Gold I Complexes

Besides intermolecular Au Au interactions, visible metal-centered emission of mononuclear Au(I) complexes is usually associated with trigonal, non-centro-symmetric coordination at Au(I). For example, mononuclear two-coordinate bis 

Di- and Polynuclear Cold(l) Complexes with Metal-Metal Interactions 

Since the first report on the photoluminescence of [Au2( X-dppm)2] [2, 3], di- and polynuclear gold(I) phosphine complexes have received considerable attention. 

Au Au(CN)2 = 3.33(1) Au OCIO3 = 3.36(2) A). As discussed in Section 5.2.3, variations in gold-anion contacts have a significant impact upon the solid-state emission of [Au2( t-dcpm)2]X2 complexes. 

The emission of [Au3(p,-dpmp)2](CF3S03)3 at about 600 nm is reassigned here to originate from a three-coordinate Au(I) site in the excited state, as found in the analogous derivative, [Au3(p,-dpmp)2(SCN)3] [38]. 

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Most of the gold cluster compounds are synthesized from mononuclear gold(I) complexes like R PAuX (X = halide, NOj, SCN, etc.) by reduction with NaBH4, Ti( /-tol)2, CO, or other reducing agents. We have recently found that the photolytic decomposition of the azido complexes R3PAUN3 in THE is another convenient method. ... 

Other cases of transition-metal ion binding to the imidazole ring N9 atom of the purine ligand have been reported in the monomer [TiCl(cp)2(pur-KA )] (cp is the cyclopentadienyl anion) with a purinate monoanion" and a series of neutral dinuclear and mononuclear gold(I) complexes with phosphine and purin-9-ate synthesized under basic conditions. There are reported examples of Mn(II) binding to N donor sites of nueleobases in biopolymeric systems, but coordinative Mn-N linkages involving isolated nueleobases, as seen in... 

Thus, the abstraction of the chlorine atom in [Au(QF5)2Cl(dppm)j [175] provides a mononuclear gold(I II) derivative with the diphosphine acting as a chelate ligand, which is an excellent starting material in the synthesis of dinuclear or polynuclear methanide and methanidiide complexes after deprotonation of the dppm ligand (first deprotonation with HNa and the second with acetylacetonate gold(I) derivatives) [198-201] (Scheme 3.3)... 

For di- and polynuclear gold(I) complexes vith two Au(I) centers held in close proximity, a lower energy 5denergy from its mononuclear counterpart is a spectroscopic signature [2, 7, 44]. Excitation to the 5da —> 6pG transition gives rise to a [5da, 6pa] excited state having a formal... 

Carbene complexes have also been prepared by transmetallation reactions. Lithiated azoles react with gold chloride compounds and after protonation or alkylation the corresponding dihydro-azol-ylidene compounds, e.g., (381) or (382), are obtained.22 9-2264 Silver salts of benz-imidazol have also been used to obtain carbene derivatives.2265 Mononuclear gold(I) carbene complexes also form when trimeric gold(I) imidazolyl reacts with ethyl chlorocarbonate or ethyl idodate.2266,2267 The treatment of gold halide complexes with 2-lithiated pyridine followed by protonation or alkylation also yields carbene complexes such as (383).2268 Some of these carbene complexes show luminescent properties.2269-2271... 

Mononuclear gold(II) complexes, consistent with a d9 configuration, must be paramagnetic (peff= 1-79 MB) and show a hyperfine four-line EPR signal, in accordance with the nuclear spin of 197Au (I = 3/2). These two properties are evidence ofa real gold(II) complex in addition to their stoichiometry. 

Rod-like mononuclear derivatives have been prepared by the reaction of a polymeric alkynyl gold(I) complex with isocyanides. The mesomorphic properties of three types ofgold(I) acetylide complexes, namely, [Au(CC-Ar)(CN-Ar)J, [Au(CC-R)(CN-Ar)J and [Au(CC-Ar)(CN-R)] (Ar = aryl with aliphatic chain, R = alkyl chain), have been systematically examined. 

Recently we showed that mononuclear ylide gold(I) complexes like [Au(CH2PR3)2]C104 have enough electron density at their gold centers to form non-supported metal-metal bonds when reacted with nearly naked silver com-... 

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