Unsaturated carbene ligands: (.eta.2-vinyl)-, (vinylcarbene)-, and (.eta.4-butadienyl)tungsten dithiocarbamate complexes

Synthesis and Characterization of Highly Fluorinated Tungsten(II) Metallacyclopropene Complexes. Kinetics and Mechanism of an Unprecedented η2-Vinyl Isomerization

“…Carbon monoxide and tert-butyl isonitrile were obtained from commercial sources and used without further purification. 13 CO was obtained from Cambridge Isotopes and used without further purification.…”

“…1 H, 13 C{ 1 H}, 31 P{ 1 H}, and 19 F NMR spectra were obtained on Varian XL-300 spectrometers at 300, 75, 121, and 281 MHz, respectively. All chemical shifts are reported in δ (ppm) units with the following abbreviations: d ) doublet, m ) multiplet, q ) quartet, s ) singlet, t ) triplet, and apr ) apparent.…”

“…Templeton and co-workers have elegantly demonstrated that η 2 -vinyl complexes can also be formed using indirect routes. For instance, addition of an anionic dithiocarbamate ligand to the cationic butadienyl complex [(S 2 CNMe 2 ) 2 W(η 4 -C 4 Ph 4 H)] + results in dechelation of the vinyl tail to form a neutral tungsten(IV) d 2 vinyl-substituted η 2 -vinyl complex of the type (S 2 CNMe 2 ) 2 W(η 2 -CPhCPhCPhCHPh) (eq 8) . In another unusual example, protonation of the carbyne complex Tp‘(CO) 2 Mo⋮CN(Me)(Bu t ) in the presence of phenylacetylene yields the cationic η 2 -vinyliminium complex [Tp‘(CO) 2 Mo(η 2 -C(Ph)C(H)C(H)N(Me)(Bu t ))] + which reacts with LiEt 3 BH to form the neutral η 2 -vinylamine complex Tp‘(CO) 2 Mo(η 2 -C(Ph)C(H)C(H)N(Me)(Bu t )) (eq 9) …”

“…For instance, addition of an anionic dithiocarbamate ligand to the cationic butadienyl complex [(S 2 CNMe 2 ) 2 W(η 4 -C 4 Ph 4 H)] + results in dechelation of the vinyl tail to form a neutral tungsten(IV) d 2 vinylsubstituted η 2 -vinyl complex of the type (S 2 CNMe 2 ) 2 W-(η 2 -CPhdCPhCPhdCHPh) (eq 8). 13 In another unusual example, protonation of the carbyne complex Tp′-(CO) 2 MotCN(Me)(Bu t ) in the presence of phenylacetylene yields the cationic η 2 -vinyliminium complex [Tp′-(CO) 2 Mo(η 2 -C(Ph)dC(H)C(H)dN(Me)(Bu t ))] + which reacts with LiEt 3 BH to form the neutral η 2 -vinylamine complex Tp′(CO) 2 Mo(η 2 -C(Ph)dC(H)C(H)dN(Me)(Bu t )) (eq 9). 14 It is surprising that there have been no kinetic studies concerning η 2 -vinyl processes given the postulated role of vinyl-stabilized intermediates in a variety of catalytic chemical transformations 15 and the prevalence of η 2vinyl complexes in organometallic chemistry.…”

Reaction of a (π-Vinylcarbene)iron Complex with Tricarbonyl(η4-1,5-cyclooctadiene)ruthenium. Preparation, Structure, and Reactivity of Novel (μ-Vinylcarbene)(Fe−Ru) Complexes

“…For the past two decades, much attention has been focused on the chemistry of mononuclear 1 − and binuclear transition-metal vinylcarbene complexes 2 , (η 4 -metallabutadiene)metal complexes 2 ‘, or η 3 :η 1 -allylidene complexes 2 ‘‘ (Chart ). − Especially, heterobinuclear vinylcarbene complexes − are of interest; however, methods of preparation of these complexes are not completely established. As for the preparation of (μ-vinylcarbene)(M 1 −M 2 ) complexes, the following two representative methods are reported: (1) reaction of (μ-methylene)(M 1 −M 2 ) 3 with alkynes (eq 1); (2) reaction of (η 1 -vinylcarbene)M 1 or 1-metallabutadiene 4 with M 2 (eq 2) .…”