Complexes with functional phosphines. 14. Coupling reactions of MeO2CC.tplbond.CCO2Me with .beta.-phosphino ketonate complexes leading to nickel, palladium, and platinum alkenyl complexes

Abstract

ChemInform Abstract The alkenyl complexes (III), (V), (VI) (X-ray analysis; space group C2/c, Z=2), (VIII) and (IX), and (XII) are obtained by reactions of the phosphino enolate complexes (I), (IV), (VII) and (XI), respectively, with the acetylenedicarboxylate (II) according to the scheme. The tendency to form trans products decreases on going from Ni(II) to Pt(II). Isomerization reactions of the new phosphino alkenyl ligands are shown to occur in the complexes (IX) and (XII) giving the bis(alkyl) complex (X) (C2/c, Z=4) as a l-cis isomer and the P,O-chelate complex (XIII).

Hemilability of Hybrid Ligands and the Coordination Chemistry of Oxazoline-Based Systems

“…In palladium( II ) chemistry such anionic P,O chelates may also behave as reactive moieties towards a wide range of electrophilic organic or inorganic reagents. In these cases, the covalent Pd−O enolate bond does not display any lability 66, 80, 104–109. However, an example of a hemilabile phosphino enolate ligand was found in the course of reactivity studies on palladium( II ) complexes with organic isocyanates which led to new multifunctional systems [Eq.…”

Catalyst Deactivation by β‐Hydride Elimination: Olefin and Alkyne Insertion into Arenido–Nickel(II) Bonds

“…The insertion of alkynes into nickel(II)-arenido bonds is described in the literature, although only with sterically demanding alkynes, which do not show β-hydride elimination. [25,26] The formation of allenes through β-hydride elimination has been reported on silver(111) surfaces where allyl moieties are activated to afford 1,2-propadiene. [27] Analogously to the mechanistic pathway of the reaction with 1-heptene described above the alkyne can be inserted into the nickel-carbon bond in two different ways (see Schemes 4 and 5), forming two isomeric allenes.…”

Platinum organometallic compounds: classification and analysis of crystallographic and structural data. Part I. Monomeric Pt(0) and partly of Pt(II) with PtC4, PtA3B and PtC2A2 chromophores

“…The mean cis -and trans -C − Pt − P bond angles are 103.5 ° (range 97.5 -117.3 ° ) and 152.7 ° (range 142.2 -160.9 ° ). There are ten derivatives (Cheney et al 1973, Bennet et al 1978, Porzio 1980, Abicht et al 1982, Braunstein et al 1989, Kemmitt et al 1992, Ghaffar et al 1996, van der Boom et al 1996, Gaw et al 1999 in which a pair of hetero-bidentate − C,P donor ligands build up a distorted square planar (PtC 2 P 2 ) geometry about each Pt(II) atom. In a yellow complex (Bennet et al 1978 ), a pair of o -C 6 H 4 PPh 2 monoanions form two four-membered metallocycles with a mean C − Pt − P bite angle of 68.73(7) ° .…”

“…In a yellow complex (Bennet et al 1978 ), a pair of o -C 6 H 4 PPh 2 monoanions form two four-membered metallocycles with a mean C − Pt − P bite angle of 68.73(7) ° . In another seven derivatives (Cheney et al 1973, Porzio 1980, Abicht et al 1982, Braunstein et al 1989, Kemmitt et al 1992, Gaw et al 1999 ), a pair of hetero-bidentate ligands create two fi vemembered metallocycles with a mean C − Pt − P bite angle of 81.6 ° (range 79 -84.1 ° ). A pair of CH 2 PPh 2 CH 2 PPh 2 ligands form a pair of fi ve-membered metallocycles (-CPCP-), with a mean C − Pt − P bite angle of 90.6 ° (Ghaffar et al 1996 ).…”