The cis influence of a series of anionic ligands X and Y has been evaluated through the magnitude of the Pt–P coupling constants for compounds of formula trans-[PtXY(PPh₃)₂]. The order of decreasing cis influence was found to be I > Cl > SePh ∼ SPh ∼ SEt > NO₃ > AcO ∼ NO₂ > H > Me > Ph > mtc (mtc = N,N-dimethylmonothiocarbamato-S); moreover, the cis influences of the various ligands was found to be additive. The X-ray structures of three representative compounds (t-4: X = Cl, Y = NO₃; t-5: X = Cl, Y = AcO and t-12: X = Y = NO₂) have also been determined.

The reaction of 1,3-bis(2-pyridyl)benzene, N⁁CH⁁N, with H[AuCl₄] has been studied under different conditions. Mono- ([N⁁CH⁁NH][AuCl₄]) and di-protonated salts ([HN⁁CH⁁NH][AuCl₄]₂ ), as well as an adduct, [(N⁁CH⁁N)(AuCl₃)₂ ], have been isolated. Very rare cyclometalated pincer derivatives, [Au(N⁁C⁁N)Cl]⁺ have been obtained as different salts, either by transmetallation from the corresponding mercury(II) derivative, [Hg(N⁁C⁁N)Cl], or by direct C–H activation. The structures in the solid state of [N⁁CH⁁NH][AuCl₄] and [Au(N⁁C⁁N)Cl][PF₆] have been solved by X-ray diffraction. Reaction of the pincer derivatives with PPh₃ , dppm (bis(diphenylphosphino)methane) and dppe (1,2-bis(diphenylphosphino)ethane) occurs with displacement of the coordinated nitrogen atoms to afford [Au(N⁁C⁁N)(Cl)(PPh₃)₂]⁺ , [Au(N⁁C⁁N)(Cl)(dppm)₂]⁺ and [Au(N⁁C⁁N)(Cl)(dppe)]⁺ , respectively. The X-ray structure of [Au(N⁁C⁁N)(Cl)(PPh₃)₂][PF₆] confirms that the ligand N⁁C⁁N is only σ-carbon bonded and the PPh₃ molecules are in a trans-arrangement. The pattern of the ³¹P{¹H}NMR spectrum of [Au(N⁁C⁁N)(Cl)(dppm)₂]⁺ , a pair of “triplets”, deserves comments: the spectrum is not of the A₂X₂ type but a case of a deceptively simple AA‘XX’ spin system.