Gold Complexes with Potentially Tri- and Tetradentate Phosphinothiolate Ligands

Reactions of [Au(PPh3)Cl], (Bu4N)[AuCl4] and the organometallic gold complex [Au(damp-C1,N)Cl2] (damp- =
2-(N,N-dimethylaminomethyl)phenyl) with the potentially tri- and tetradentate proligands PhP(C6H3−SH-2−R-3)2 (H2L1a, R = SiMe3; H2L1b, R = H) and P(C6H4−SH-2)3 (H3L2) result in the formation of mono- or dinuclear
gold complexes depending on the precursor used. Monomeric complexes of the type [AuL1Cl] are formed upon
the reaction with [Au(damp-C1,N)Cl2], but small amounts of dinuclear [AuL1]2 complexes with gold in two different
oxidation states, +1 and +3, have been isolated as side-products. The dinuclear compounds are obtained in better
yields from [AuCl4]-. A dinuclear complex having two Au(III) centers can be isolated from the reaction of [Au(PPh3)Cl] with H3L2, whereas from the reaction with H2L1b the mononuclear [Au(Ph3P)HL1b] is obtained, which
contains a three-coordinate gold atom. Comparatively short gold−gold distances have been found in the dinuclear
complexes (2.978(2) and 3.434(1) Å). They are indicative of weak gold−gold interactions, which is unusual for
gold(III).