A stable crystalline carbene

Reactivity of Diaminogermylenes with Ruthenium Carbonyl: Ru3Ge3 and RuGe2 Derivatives

“…27 The WINGX program system 28 was used throughout the structure determinations. CCDC deposition numbers: 824261 (2·(C 7 H 8 ) 2 ) and 824262 (3).…”

“…Thus, the triruthenium cluster [Ru 3 {µ-Ge(NCH 2 CMe 3 ) 2 C 6 H 4 } 3 (CO) 9 ], which has a planar Ru 3 Ge 3 core and an overall C 3h symmetry, has been prepared in quantitative yield by treating [Ru 3 (CO) 12 ] with an excess of the cyclic 1,3-bis(neo-pentyl)-2-germabenzimidazol-2-ylidene in toluene at 100 o C, but, under analogous reaction conditions, the acyclic and bulkier Ge(HMDS) 2 (HMDS = N(SiMe 3 ) 2 ) quantitatively leads to the mononuclear ruthenium(0) derivative [Ru{Ge(HMDS) 2 } 2 (CO) 3 ]. Mixtures of products have been obtained from the reactions of [Ru 3 (CO) 12 ] with the cyclic and very bulky 1,3-bis(tert-butyl)-2-germaimidazol-2-ylidene under various reaction conditions.…”

“…3 However, in contrast with the coordination chemistry of NHMs, which has been developed gradually but slowly since their discovery, 4,5 that of NHCs blossomed very rapidly 6 because some NHC complexes soon demonstrated to be excellent homogeneous catalysts for processes that are very useful in organic synthesis. 7 This intense NHC research activity has also included transition metal clusters, 8-10 on which NHCs are prone to undergo multiple C-H and C-N bond activation processes that cannot occur in mononuclear complexes.…”

C4-bound imidazolylidenes: from curiosities to high-impact carbene ligands

“…11 This is a direct consequence of the different arrangement of the heteroatoms, which are considered to be crucial for stabilizing the carbene via resonance and inductive carbon-heteroatom interactions. Energy decomposition analyses of the tautomers A and B of imidazole predict that the C2 carbene A is about 80 kJ mol À1 more stable than the C4 carbene B (Scheme 3).…”

Olefin Hydroborations with Diamidocarbene–BH3 Adducts at Room Temperature

“…Numerous transition metal-based hydroboration catalysts have been developed over the past several decades to improve chemo-, regio-and/or stereo-selectivities [5][6][7][8][9]. Efforts toward the development of organocatalyzed analogues have also been pursued, with particular attention focused on stable carbenes, including the cyclic (alkyl)(amino) carbenes (CAACs) and the N-heterocyclic carbenes (NHCs) [10][11][12][13][14]. These carbenes form Lewis acid-base adducts upon exposure to various BH 3 complexes containing dative ligands, such as dimethylsulfide (SMe 2 ) [15][16][17][18][19].…”