Synthesis and reactions of the cationic thiocarbyne [HC(pz)3](CO)2W.ident.C-SMe+. Reactions of the thiocarbene [HC(pz)3](CO)2W[.eta.2-CHSMe]2+ with nucleophiles

Cyclopentadienyl Ligand Effects on Enthalpies of Protonation of the Ru−Ru Bond in Cp‘2Ru2(CO)4Complexes

“…For complexes 1 − 5 , the ν(CO) values show that the Cp‘ ligand donor abilities increase in the following order (average ν(CO) values, cm -1 , in parentheses): Cp (2046) ∼ Ind (2046) < Cp ⧧ (2042) < HB(pz) 3 (2039) << Cp* (2019). The similar donor abilities of Cp, Ind, and Cp ⧧ are consistent with previous comparisons of these ligands. 8c,, The HB(pz) 3 ligand is known to be a somewhat stronger donor than Cp, , as is also found in the present trend. The Cp* ligand is a significantly stronger donor than any of the other ligands.…”

“…Since 3 exists in the nonbridged form only, there is no bridge to nonbridge reaction (Δ H b ) to reduce its basicity (−Δ H MHM ). Therefore, the stronger donor ability of HB(pz) 3 compared with Cp should make 3 more basic than 2 …”

Effect of Ligand Variation on the Site of Protonation in the Metal Carbynes CpL2Mo⋮CBu and TpL2Mo⋮CBu [L = CO, P(OR)3]

“…However, the structure could be assigned as carbene 11 (eq 4) on the basis of certain resonances in its 1 H and 13 C spectra. A proton signal at 12.6 ppm and a carbon resonance at 260 ppm are in agreement with similar Tp carbene complexes, one of which was characterized by X-ray crystallography 5b …”

“…The protonation product is dependent on the metal, the ancillary ligands, and the counterion of the acid. Products obtained from simple protonation of alkylidyne complexes include metal carbenes (alkylidenes) from protonation at the carbyne carbon, metal hydrides from addition to the metal center, and “face-protonated” alkylidynes in which the product is an alkylidene whose C−H bond is engaged in agostic interaction with the metal. , In the presence of coordinating anions, carbyne protonation can induce further reaction to produce η 2 -acyl complexes 8 and compounds in which the original alkylidyne ligand has been lost via protonolysis. 6c,d …”

Hexacarbonyls and Carbonyl Complexes of Carbon σ-Bonded Ligands of Chromium, Molybdenum and Tungsten

“…The carbyne cation [W(CO) 2 (=CSMe){HC(pz) 3 }] + protonates to form the dication [W(CO) 2 {=CHSMe}{HC(pz) 3 }]2+ , a species which reacts readily with nucleophiles 702. A similar reaction occurs for the neutral species [W(CO) 2 (=CSMe)Tp] which protonates to form the cationic 2 -thiocarbene [W(CO) 2 { =CHS Me } Tp] + .…”