Syntheses and structural aspects of rigid aryl palladium(II) and platinum(II) complexes X-ray crystal structure of o,o'-bis[(dimethylamino)methyl]phenylplatinum(II) bromide

Abstract

The tridentate monoanionic ligand o, o'-(Me{2}NCH{2}){2}C{6}H{3} (NCN') has been used to synthesize novel aryl-palladium(II) and -platinum(II) complexes [PtR(NCN')] and [MX(NCN')] (M = Pt, Pd). Three synthetic procedures are described, namely: (i) reaction of the cationic complex [M(NCN')(H{2}O)]}+{ with KX or NaX to give [MX(NCN')] (X = Cl, I, O{2}CH, NCS, NO{2}, NO{3}); (ii) displacement reactions using AgX with [MBr(NCN')] to give [MX(NCN')] (X = CN, O{3}SCF{3}. O{2}CMe, O{2}CCF{3}) and (iii) transmetallation reactions of [PtBr{C{6}H{3}(CH{2}NMe{2}){2}-o,o'}] with organolithium to give [PtR{C{6}H{3}(CH{2}NMe{2}){2}-o,o'}] (R = Ph, o-, m-, p-tolyl, C@?CPh, C@?C-p-tolyl). All complexes have been characterized by elemental analysis, and IR, }1{H and }1{}3{C NMR spectroscopy.An X-ray diffraction study has shown that [PtBr{C{6}H{3}(CH{2}NMe{2}){2}-o,o'}] (2) has a square-planar structure, in which the tridentate ligand is bonded via C(ipso) (Pt@?C 1.90(1) @9), and two mutually trans-N donor atoms (Pt@?N(1) 2.07(1), Pt@?N(2) 2.09(1) @9). The fourth site trans to C(ipso) is occupied by bromine (Pt@?Br 2.526(2) @9). The two chelate rings (N@?Pt@?C(ipso) 82.9(5) and 81.5(5)}o{) are distinctly puckered, with the two NMe{2} groups on opposite sides of the aryl plane. The Pt@?C bond in 2 is shorter than analogous bonds in other arylplatinum(II) complexes, as a result of (i) the rigid structure of the tridentate ligand and (ii) the presence of two hard N donor atoms trans to one another across the platinum centre.