SYNTHESIS, STRUCTURE AND REACTIVITY OF STABLE DIANIONIC ORGANOMETALLIC COMPLEXES OF PT(IV) - CRYSTAL-STRUCTURE OF [PETPH(3)](2)[CIS-PT(C6F5)(2)CL-4] AND [NBU(4)][MER-PT(C6F5)(2)CL-3(NH2-P-C6H4CH3)]

The stable dianionic complexes Q(2)[cis-Pt(C6F5)(2)Cl-4] (Q=NBu(4)(+), 1; PEtPh(3)(+), 2) have been obtained from reaction of the correspond ing Q(2)[trans-Pt(C6F5)(2)Cl-2] complexes with Cl-2 in CCl4 solution. [PEtPh(3)](2)[cis-Pt(C6F5)(2)Cl-4] is the first dianionic organometall ic complex of Pt(IV) structurally characterized by X-ray diffraction. It crystallizes with two CH,CI, 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) Angstrom, beta = 106.42 (3)degrees, V = 5563(2) Angstrom(3), Z=4 (20 degrees C). [NBu(4)](2)[c is-Pt(C6F5)(2)Cl-4] has been used as starting material in the synthesi s of [NBu(4)][mer-Pt(C6F5)(2)Cl-3(NH2-p-C6H4CH3)], 3. The crystal stru cture of this new stable Pt(IV) compound has been determined. It cryst allizes in the monoclinic system, space group P2(1)/n (No. 14), a = 11 .122(3), b = 23.150(3), c = 16.086(3) Angstrom, beta = 105.79(3)degree s, V = 3985(2) Angstrom(3), Z = 4 (20 degrees C). The disposition of t he two C6F5 groups is very similar in both molecules. This is a conseq uence of steric constraints imposed by the octahedral coordination of the platinum atom.