Heteropolynuclear Phosphide Complexes: Phosphorus as Unique Atom Bridging Coinage Metal Centres

Abstract

In this paper we describe the synthesis and reactivity of the diphenylphosphine derivatives [Au(C6F5)(PPh2H)] and trans-[Au(C6F5)2(PPh2H)2]ClO4. Reactions of the latter or the neutral [Au(C6F5)3(PPh2H)] with the appropriate Group 11 metal reagents (M = Au, Ag, Cu) in the presence of acetylacetonate afford a series of novel Au(III)-M phosphido-bridged complexes, which have been scarcely represented to date. The crystal structure of the tetranuclear [(Au(C6F5)2(mu-PPh2)2Ag)2] and the dinuclear [Au(C6F5)3(mu-PPh2)M(PPh3)] (M = Au,Ag) complexes were established by X-ray diffraction methods. The synthesis and deprotonating activity of the anionic gold(III) complex PPN[Au(C6F5)3(acac)] (PNN = [N(PPh3)2]+) was studied.

Perfluoroarylgold complexes

“…The usual method for displacing the labile ligand tht by phosphorus donor ligands extensively employed with a variety of tertiary phosphines has also been used recently for the synthesis of pentafluorophenyl complexes containing primary or secondary phosphines, such as diphenylphosphine [97,98], phenylphosphine [99] or 1,2-diphosphinobenzene [100]. Thus, the gold(I) or gold(III) phosphino derivatives [Au(C 6 F 5 )(LH)] (LH = PPh 2 H, PPhH 2 ), [Au(C 6 F 5 ) 3 (LH)] (LH = PPh 2 H, PPhH 2 , 1,2-C 6 H 4 (PH 2 ) 2 ) or trans-[Au(C 6 F 5 ) 2 (PPh 2 H) 2 ]ClO 4 have been described, the latter showing a trans disposition of the ligands as its IR spectrum indicates [97] (see Scheme 12).…”

“…Thus, the gold(I) or gold(III) phosphino derivatives [Au(C 6 F 5 )(LH)] (LH = PPh 2 H, PPhH 2 ), [Au(C 6 F 5 ) 3 (LH)] (LH = PPh 2 H, PPhH 2 , 1,2-C 6 H 4 (PH 2 ) 2 ) or trans-[Au(C 6 F 5 ) 2 (PPh 2 H) 2 ]ClO 4 have been described, the latter showing a trans disposition of the ligands as its IR spectrum indicates [97] (see Scheme 12). These products, and mainly the gold(I) compounds, are moderately stable and can be easily deprotonated due to the high acidity of the phosphinic protons.…”

“…, which contain two (the first two) or four (the latter) phosphido bridging ligands, have been obtained [97]. A series of tetranuclear neutral complexes [Au(C 6 F 5 ) 2 (-PPh 2 ) 2 M] 2 (M = Cu, Ag, Au) can also be isolated by reaction of the same gold(III) starting material with M(I) salts in the presence of acetylacetonate as deprotonating agent (2:1), as shown in Scheme 15. Furthermore, reaction of the mixed Au III /Ag I diphenylphosphide complex [Au(C 6 F 5 ) 2 (-PPh 2 ) 2 Ag] 2 with an equimolecular amount of [AgCl(PPh 3 )] leads to the formal insertion of the latter into the starting complex, yielding the [103].…”

“…Thus, its reaction with phosphino-or pentafluorophenylgold(I) or silver(I) complexes in the presence of the same deprotonating agent leads to trinuclear diphosphides displaying a tricoordinated gold(I) or silver(I) center (see Scheme 17). The bridging chlorine atom of Probably thanks to the stabilizing effect of the perfluorophenyl groups, the crystal structures of many phosphidegold derivatives (14) has been established [97][98][99][100][101]103]. The comparison of the Au III -C distances trans to phosphide (average 2.073Å) and trans to pentafluorophenyl (average 2.061Å) indicates a stronger trans influence for phosphide ligands than for the carbon donor group.…”

Gold Phosphide Complexes

“…28 As in the gold(I) species, none of them show intermetallic contacts. [29][30][31] The dinuclear neutral or anionic products [Au(C 6 F 5 ) 3 . 32 An alternative strategy for the synthesis of some of them involves the use of [Au(C 6 F 5 ) 3 …”