Organoamidometallics. I. Syntheses of [N,N′-Bis(Polyfluorophenyl)Ethane-1,2-Diaminato(2-)]Platinum(II) Complexes by Decarboxylation

Abstract

Reaction of PtCl2(en) (en = ethane-1,2-diamine) with thallous pentafluorobenzoate in hot pyridine ( py ) or 4-methylpyridine ( mepy ) yields the [N,N′- bis (2,3,5,6-tetrafluorophenyl)ethane-1,2-diaminato(2-)]platinum(II) complexes, Pt[N(p-HC6F4)CH2]2( py )2 (1a) and Pt[N(p- HC6F4)CH2]2( mepy )2 (1b). The route to (1a) is considered to involve formation of [Pt(en)( py )2](O2CC6F5)2 (2), decarboxylation of (2) into Pt(NHCH2)2( py )2 (1c) and pentafluorobenzene, and nucleophilic attack of (1c) on C6F5H. Complex (1a) has also been prepared by decarboxylation of (2), reaction of PtI2(en) and TlO2CC6F5, and reaction of PtCl2(en), C6F5H, and TlO2CC6F4H-p in boiling pyridine. From reaction of PtCl2(en), TlO2CC6F4H-p, and the appropriate polyfluorobenzene (RF) in boiling pyridine or 4-methylpyridine, the organoamidoplatinum compounds Pt(NRCH2)2L2(R = C6F5, p-MeC6F4, p-ClC6F4, p-BrC6F4, p-IC6F4, 2,3,5-F3C6H2, or p-C6F5C6F4, L = py and R = C6F5, L = mepy ) have been prepared. Analogous reactions of PtCl2( pn )( pn = propane-1,3-diamine) give the complexes Pt[NR(CH2)3NR]( py )2 (R = C6F5 or p-HC6F4). Spectroscopic evidence for the structures is discussed. The polyfluorophenyl groups confer stability to water on ethane-1,2-diaminato(2-)platinum(II) complexes, and this is attributable to delocalization of non-bonded lone pairs from the amido nitrogens into the polyfluorophenyl rings.