STEREOSELECTIVE OXIDATIVE-ADDITION REACTIONS OF DIHALOGENS AND COPPER(II) HALIDES TO SQUARE-PLANAR ORGANOPLATINUM(II) COMPLEXES CONTAINING HARD-N AND C-DONOR ATOMS - MOLECULAR-STRUCTURES OF [BC,DE-BIS(8-DIMETHYLAMINO-1-NAPHTHYL)]-AFDIIODOPLATINUM(IV) AND AB-DIBROMO[CF,DE-BIS(8-DIMETHYLAMINO-1-NAPHTHYL)]PLATINUM(IV)

Oxidative additions of electrophiles X2 (X = Br or I) and CuX2 (X = Cl or Br) to the complexes cis-bis[2-(dimethylaminomethyl)phenyl]platinum(II) 1 and cis-bis(8-dimethylamino-1-naphthyl)-platinum(II) 3 have been investigated. Those with X2 afford the respective trans-X2 platinum(IV) products, whereas with CuX2 the cis-X2 platinum(IV) products are obtained, except for the reaction of 1 with CuBr2 which yields the trans-dibromo product. There is no evidence for cis-trans or trans-cis isomerizations of these octahedral platinum(IV) products in solution. On the basis of these stereoselective product formations (and earlier results) the proposed mechanisms are an S(N)2 type for the reactions with dihalogens and an inner-sphere ligand-transfer oxidation for the reactions with copper(II) halides. The mechanisms of the reactions of X2 and CuX2 with trans-bis[2-(dimethylaminomethyl)phenyl]platinum(II) 2 are the same as with 1 (and 3) but lead to other geometrical isomers. The stereochemistry of two of the oxidative addition products, i.e. [bc,de-bis(8-dimethylamino-1-naphthyl)]-af-diiodoplatinum(IV) 5c and ab-dibromo[cf,de-bis(8-dimethylamino-1-naphthyl)]platinum(IV) 5e, have been established by X-ray crystal structure determinations. Crystals of 5c are orthorhombic, space group Pbca, with a = 7.825(3), b = 17.803(2), c = 37.873(6) angstrom, Z = 8 and R = 0.032 for 2962 reflections with I > 2.5-sigma-(I). Crystals of 5e are monoclinic, space group P2(1)/c, with a = 9.696(2), b = 9.722(6), c = 26.81(3) angstrom, beta = 90.46(4)-degrees, Z = 4 and R = 0.083 for 3060 reflections with I > 2.5-sigma-(I).