Synthesis and reactions of some cyclopentadienyl complexes of platinum

Abstract

Reaction of PtCl(X)(COD), COD = 1,5-cyclooctadiene (X = CH3, Cl) with TlC5H5 gives η1-C5H5 complexes Pt(η1-C5H5)(Y)(COD) (Y = CH3, Cl, η1-C5H5). Pt(η1-C5H5)(CH3)(COD) is converted to Pt(η5-C5H5)(CH3)L by treatment with L = CO, P(OCH3)3, P(OC6H5)3, P(OCH3)(C6H5)2; treatment with CF3C≡CCF3 or maleic anhydride results in a Diels–Alder addition to the diene residue of the η1-C5H5 ring from the side of the ring opposite the Pt atom. Diels–Alder addition occurs between CF3C≡CCF3 and one η1-C5H5 ring of Pt(η1-C5H5)2COD; the other η1-C5H5 converts to η5 displacing the COD, and the norbornadiene is bidentate. 1H and 13C nmr data are presented for some η1 and η5-C5H5 complexes.

Preparation and properties of hydroxo(methyl)-1,2-bis(diphenylphosphino)ethaneplatinum(II). A trans-influence series including .sigma. carbon donor ligands based on platinum-phosphorus coupling constants

“…28 Other ^'-cyclopentadienyls of platinum(II) have been described recently. 29,30 In the NMR spectrum of [Pt(CH3) (SbPh3) (dppe) ] BF4, the central part of the Pt-CH3 resonance consists of a sharp triplet owing to the accidental equality of 3/hp(c¡s) and 3JHp(trans)> but the 195Pt satellites are very broad. 31P coupling in the satellites cannot be resolved, and 2/PtcH3 cannot be obtained.…”

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…Stereochemical investigations with fumaro-and maleonitrile have confirmed a concerted [4+2] mechanism. 563 Analogous reactions of various dienophiles with η 1 -Cp in complexes such as (COD)(η 1 -Cp) 2 Pt, (COD)(η 1 -Cp)Pt(CH 3 ), [567][568][569] (η 5 -Cp)(η 1 -Cp)Mo(NO)(η 2 -S 2 CNMe 2 ), 570 or (η 5 -Cp) 2 (η 1 -Cp) 2 Nb, 571 (Cp) 2 MCl 2 (M ) Ti, Zr) 572 have also been described, giving cycloadducts such as 323-326, respectively. Nickelocene, (η 5 -Cp) 2 Ni, has also been shown to give, besides binuclear compounds with bridging acetylene, low to moderate yields of formal Diels-Alder products 327; 573,574 however, the mechanism by which these are formed is not clear.…”

Synthesis, chemistry, and low-temperature crystal and molecular structure of [.mu.-(.eta.5-cyclopentadienyl)beryllio]octahydropentaborane, [.mu.-(.eta.5-(C5H5)Be]B5H8

“…-40 °C produces good yields of ^-(i?5-C5H5)-Be]B5H8 according to eq 2. The product is a colorless solid KB5H8 + (i75-C5H5)BeCl -KC1 + Mvj5-C5H5)Be]B5H8 (2) of low volatility that melts at ca. 38 °C.…”