Synthesis of Bis-(2,6-dinitroaryl)palladium(II) and Mono-(2,6- dinitroaryl)platinum(II) Complexes. A New Example of the Transphobia Effect and of Transmetallation from Pt to Hg

Abstract

The reaction of [Pd(k2-Ar)(O,O-acac)] (k2-Ar = k2-C,O-C6(NO2)2-2,6-(OMe); 1) with one equiv of RNC gives [Pd(k2-Ar)(O,O-acac)(CNR)] [R = Xy (2a), tBu (2b)] and with four equiv of XyNC, trans-[Pd(k1-Ar)2(CNXy)2] (k1-Ar = k1-C,O-C6(NO2)2-2,6-(OMe); 3). These complexes has also been obtained (1) by reacting Tl(acac) with one equiv of trans-[Pd(k1Ar)Cl(CNXy)2] (4), obtained in turn by reacting trans-(NMe4)2[Pd(k1-Ar)Cl(µ-Cl)]2 (5) with four equiv of XyNC or (2) by reacting [Pd(k1-Ar)(C-acac)(phen)] (6) with four equiv of XyNC. cis-[Pt(k2-Ar)(k1-Ar)(PPh3)] (7) reacts (1) with Hg(OAc)2 (1:1) to afford a mixture of [Hg(Ar)(OAc)], cis-[{Pt(k1-Ar)(PPh3)}2(µ-OH)(µ-OAc)] (8) and trans-[{Pt(k1-Ar)(PPh3)}2(µOH)2] (9) or (2) with HgCl2 (1:1) to give trans-[{Pt(k1-Ar)(PPh3)}2(µ-Cl)2] (10), which reacts with excess of Ag(OAc) to give 8. The reaction of 10 with excess of KOH, or with Tl(acac) (1:1) gives 9. Reaction of palladium complex 5 with two equiv of Hg(OAc)2 affords trans[Pd(k2-Ar)(µ-OAc)]2 (11). The crystal structures of 2a, 2b, 3, 5, 8, 9, and 11 have been determined.