Bis(selone) Complexes of Palladium(II), Platinum(II), and Gold(III): Synthesis and Structural Studies

Abstract

New bis(selone)‐based metal complexes, [MnLxCly] {M = Pd, L = 3,3′‐[(2‐bromo‐1,3‐phenylene)bis(methylene)]bis(1‐mesityl‐1,3‐dihydro‐2H‐imidazole‐2‐selone) (15), n = 2, x = 2, y = 4, C64H66N8Cl4Br2Se4Pd2) (17); M = Pt, L = 15, n = 2, x = 2, y = 4, C64H66N8Cl4Br2Se4Pt2 (18); M = Au, L = 15, n = 1, x = 1, y = 1, C32H33N4Se2BrAuCl (19)} were synthesized by the reaction of bis(selone) (15) with Pd(COD)Cl2 (yield 31 %), Pt(COD)Cl2 (yield 34 %), and [AuCl(SMe2)] (yield 57 %), respectively. Single‐crystal X‐ray diffraction analysis reveals that 17 and 18 exist as [2+2] dinuclear self‐assembled 24‐membered metallamacrocycles, while the spectroscopic data for the gold(III) complex 19 indicate that it exists as a new organogold(III) bromide, where a facile oxidative addition occurs across the C–Br bond. Natural bond orbital analysis showed the variation of the natural population analysis (NPA) charge on the Se atoms, from negative to positive, after complexation (15: –0.25; 17: 0.08; 18: 0.09–0.13). Moreover, the NPA charge on the metal atom is found to be negative for complexes 17 and 18 (Pd: –0.133 for 17; Pt: –0.23 and –0.251 for 18). However, for complex 19, the gold atom carries a positive charge (0.15).