Synthesis, structure and reactivity of stable dianionic organometallic complexes of Pt(IV). Crystal structure of [PEtPh 3] 2[ cis-Pt(C 6F 5) 2Cl 4] and [NBu 4mer-Pt(C 6F 5) 2Cl 3- (NH 2- p-C 6H 4CH 3)

Abstract

The stable dianionic complexes Q 2[ cis-Pt(C 6F 5) 2Cl 4] (Q=NBu 4 +, 1; PEtPh 3 +, 2) have obtained from reaction of the corresponding Q 2[ trans-Pt(C 6F 5) 2Cl 2] complexes with Cl 2 in CCl 4 solution. [PEtPh 3] 2[ cis-Pt(C 6F 5) 2Cl 4] is the first dianionic organometallic complex of Pt(IV) structurally characterized by X-ray diffraction. It crystallizes with two CH 2Cl 2 solvent molecules per complex molecule. The crystal system is monoclinic and the space group is C2/ c (No. 15), a = 23.648(5), b = 13.895(3), c = 17.651(4) A ̊ , β = 106.42(3)°, V = 5563(2) A ̊ 3, Z = 4 (20 °C) . [NBu 4] 2[ cis-Pt(C 6F 5) 2Cl 4] has been used as starting material in the synthesis of [ NBu 4][mer- Pt( C 6 F 5) 2 Cl 3( NH 2-p- C 6 H 4 CH 3)] , 3 . The crystal structure of this new stable Pt(IV) compound has been determined. It crystallizes in the monoclinic system, space group P2 1/ n (No. 14), a = 11.122(3), b = 23.150(3), c = 16.086(3) A ̊ , β = 105.79(3)°, V = 3985(2) A ̊ 3, Z = 4 (20°C) . The disposition of the two C 6F 5 groups is very similar in both molecules. This is a consequence of steric constraints imposed by the octahedral coordination of the platinum atom.