Synthesis of Cyclometallated Pt(II) Complexes of a Bulky Bipyridine Ligand

Abstract

Treatment of 3,4,5,6-tetraphenyl-2,2′-bipyridine (LH) ( 7) with [PtCl2(dmso)2] (dmso = dimethyl sulfoxide) in chloroform afforded the cyclometallated square-planar platinum(II) complex [PtCl(L)] ( 8) and the octahedral Pt(IV) complex mer-[PtCl3(L)] (9) containing an anionic tridentate (C^N^N) ligand. The chloride of ( 8) can be easily replaced by trifluoroacetate to yield [(L)PtO2CCF3] (10). Reaction of (8) with the alkyne HC≡CC6H4Bu t -4 resulted in the formation of [(L)PtC≡CC6H4Bu t -4] (11). Treatment of ( 8) with 4-dimetylaminopyridine (DMAP) and PPh3 in dichloromethane, and the subsequent addition of NH4PF6 in methanol produced the salts [Pt(DMAP)(L)]PF6 ( 12) and [Pt(PPh3)(L)]PF6 (13), respectively. In a similar manner, reaction of (8) with 0.5 equiv. of bis(diphenyl-phosphino)methane (dppm) formed the dppm-bridged binuclear dicationic salt [(L)Pt(dppm)Pt(L)][PF6]2 (14).

Syntheses of Au(III) and Au(I) Complexes of 3,4,5,6-Tetraphenyl-2,2´-bipyridine

“…Some of the basic ligand types (I-VII) are depicted in Figure 4. Facile synthetic routes to cyclometallated Rh(III), Pd(II) and Pt(II) complexes (Ollangnier et al, 2008;Perera, 2018;2020a) of 3,4,5,6-tetraphenyl-2,2´-bipyridine (LH) VIII and noncyclometallated complexes of it with Cu(I), Ag(I) and Re(I) were reported (Perera, 2020b;2021;2022). Thus, it is interesting to explore the chemistry of gold with this bulky bipyridine ligand VIII (Scheme 1).…”