Electrophilic and nucleophilic reactions of the vinylidene complex [Cp(PMe3)2Ru:C:C(SMe)2]BF4 and its derivatives

Abstract

attempted to evaluate their effects on the electron density at Ru by comparing the chemical shifts of their Cp proton resonances.As seen from the data in Table I, these resonances move to lower field in the order -C=C-SMe" = -C(OMe)=C(H)SMe" > -C=CSMe2 > S(Me)C=CSMe > MeSC=CMe > =C(OR)CH2SMe > =C=C(R)SMe > =C=C(R)SMe2+. The trend indicates that -bound ligands such as acetylides and vinyl groups are the better donors, while the -alkyne, car bene, and vinylidene ligands are the better -acceptors. The sulfoniovinylidene ligand in [Cp(PMe3)2Ru=C=C(H)(SMe2)](BF4)2 is the bestacceptor, partly due to bonding that involves some Ru=C carbyne character. 8520787).Supplementary Material Available: Tables of thermal parameters, hydrogen parameters, and additional bond angles (5 pages); a table of calculated and1 observed structure factors (16 pages). Ordering information is given on any current masthead

Unusual Formation and Reactivity of a Diplatinum μ-Phenylethenylidene Complex: Synthesis and Structures of cis,cis-[(PPh3)(C6F5)2Pt(μ-η1:η3-CHPhCCO)Pt(PPh3)2] and cis,cis-[(PPh3)2Pt{μ-η2(C,S):η1(C)-C(SPh)(CH2Ph)}Pt(C6F5)2(CO)] Dinuclear Compounds

“…These differences are comparable to those reported in complexes [Pt(PEt 3 ) 2 (DHT-H)][PF 6 ],32a {Pd(PPh 3 )Cl[S(Me)CH 2 ]},33a and {(PPh 3 ) 2 Pd[S(Me)CH 2 ]}[PF 6 ],33b in which the M−P bond - trans to the carbon atom is longer than the M−P bond trans to the sulfur atom, and have been interpreted in terms of a stronger trans influence for carbon than for sulfur atoms . The angle S(1)−Pt(2)−C(14) [47.7(4)°], similar to those of other three-membered (M−S−C) metallacyclic complexes, , is considerably smaller than the P(1)−Pt(2)−P(2) angle of 106.45(13)°, indicating a distorted square planar coordination for Pt(2). The dihedral angle between the S(1)−Pt(2)−C(14) and the Pt(2)−P(1)−P(2) planes is 10.8(3)°.…”

Internal Alkyne Isomerization to Vinylidene versus Stable π-Alkyne: Theoretical and Experimental Study on the Divergence of Analogous Cp*Ru and TpRu Systems

“…The conversion of internal alkynes to vinylidenes (RCCR′ → :CCRR′) is a quite uncommon process that has just emerged during the last few years as a new promising route for the transformation of internal alkynes via vinylidene intermediates . Earlier, this process had only been reported for a series of heteroatom-substituted alkynes, namely alkynylsilanes, tin acetylides, 1-iodo-1-alkynes, and mercaptoacetylene . In recent times, the migration of carbon substituents has been shown to be possible, opening a novel access to disubstituted vinylidenes from internal alkynes.…”

Alkyneselenolate vs Selenoketenyl Coordination: Synthesis and Reactivity of [Ir(SeC⋮CC6H4Me-4)(CO)(PPh3)2]

“…16 Thus, secondary alkylation of the alkyneselenolate appears to be followed by dissociation of the alkynyl selenoether and replacement by iodide. Complexes of alkynyl selenoethers remain rare, 2,17,18 although Angelici's elegant studies on the synthetic versatility of alkynyl thioether complexes 19 presages a similarly rich chemistry for selenium. The apparent lability of the MeSeCtCR group is consistent with the generally accepted weak coordination of selenoethers.…”