The Versatility of Lithium Reagents in Synthetic Organometallic Chemistry: Their differing reactions with [Cp^*Mo(NO)(CH₂SiMe₃)₂]

Abstract

[Cp*Mo(NO) (CH,SiMe,),] exhibits three principal types of reaction with the various lithium reagents investigated during this study, namely: regioselective deprotonation, reduction, and addition. Deprotonation of the reactant, achieved by treatment with lithium amide

The Elusive 16-Electron Cp*M(NO)Me2(M = Mo, W) Complexes and Their Spontaneous Conversions to Cp*M(NMe)(O)Me Isomers

“…The physical properties of solid 4 are similar to those of monomethyl 1 , but contrast with the established trend generally associated with this class of bis(alkyl) complexes. For example, the monomeric complexes Cp*Mo(NO)R 2 (R = CH 2 SiMe 3 , CH 2 CMe 3 , CH 2 CMe 2 Ph) are red-purple crystalline solids which dissolve readily in all common organic solvents to form intensely purple solutions. , In contrast, solid 4 is a pale-yellow microcrystalline powder that is sparingly soluble in alkane solvents and Et 2 O and dissolves readily only in CH 2 Cl 2 and CHCl 3 , producing intensely purple solutions. A dimeric formulation for solid 4 is indicated by an intense peak at m / z = 583 in its MALDI TOF spectrum, but EI and FAB experiments reveal only the presence of monomeric 4 .…”

“…We have an abiding interest in the series of 16e, d 4 metallonitrosyl complexes of general formula Cp‘M(NO)R 2 (Cp‘ = η 5 -C 5 H 5 (Cp), η 5 -C 5 Me 5 (Cp*); M = Mo, W; R = −alkyl, aryl), and we continue to explore their rich and diverse chemistry . During our investigations, we have established that the Lewis-acid character of these compounds is due to the π-acidic nitrosyl ligand stabilizing two of the three metal d π orbitals.…”

“…Furthermore, we have shown that while the relative Lewis acidities of these compounds are determined by the electronic structures of the different Cp‘M(NO) fragments, the relative electrophilicities of these complexes are strongly dependent upon the steric properties of R. In general, the steric influences of the alkyl ligands in Cp‘M(NO)R 2 complexes preclude reaction pathways that are initiated by close approach to the metal center of all but the smallest nucleophiles. Thus, bulky alkyl ligands such as −CH 2 CMe 3 and −CH 2 SiMe 3 are able to shield the metal center and impede the coordination of electron-rich molecules to M. 7a,8a The behavior of these complexes toward electrophiles is similarly dictated by steric effects and usually involves the generation of adducts at the nitrosyl O atom (eq 1), as opposed to cleavage of a M−C bond 8a. Hence, the most significant reactivity patterns for these compounds are initiated by the unimolecular extrusion of R−H, rather than via addition reactions …”

Mechanistic investigation on hydrogenation and hydrosilylation of ethylene catalyzed by rhenium nitrosyl complex

“…Furthermore, it exerts a relatively strong trans-influence or trans-effect, thus leading to metal-ligand bonds activated [11][12][13][14]. Special attention was paid to nitrosyl complexes [15][16][17][18][19][20]. Berke and his group have studied the chemistry of nitrosyl-substituted transition metal hydrides [21][22][23] in recent years such as trans-W(CO) 2 H(NO)(PR 3 ) 2 , Re(CO)H 2 (NO)(PR 3 ) 2 , MnH(NO) 2 (PR 3 ) 2 , ReH(NO) 2 (PR 3 ) 2 , and demonstrated that the nitrosyl ligand can activate the M-H bond and induce a quite strong hydridic polarization.…”

Proton Addition to an Anionic Carbene Complex as a Route to Seven-Coordinate Methyl Carbonyl Complexes in Equilibrium with η2-Acyl Complexes

“…Anionic carbene complexes are rare relative to neutral and cationic carbene complexes. Reactions of several anionic group VI carbene complexes have been reported during the past decade. − Protonation at metal followed by hydride migration to a carbene ligand has been observed for the anionic Cp carbene complex [Cp(CO) 2 MoC(κ 2 -C,N-(CH 2 ) 3 NMe))] - ( 1 ), which resulted in the formation of the η 2 -alkylamine complex Cp(CO) 2 Mo(η 2 -C,N-CH(κ 2 -C,N-(CH 2 ) 3 NMe)) ( 2 ) (Scheme ) . A related migration was observed for the carbene complex Cp(CO) 2 (η 1 -C(O)Ph)WC(κ 2 -C,N-(CH 2 ) 3 NMe) ( 3 ), in which the benzoyl ligand migrates to the carbene ligand to form Cp(CO) 2 W(η 2 -C,N-C(κ 2 -C,N-(CH 2 ) 3 NMe)(C(O)Ph)) ( 4 ) (Scheme ) …”