Controlled nucleophilic activation of different sites in [Mo2Cp2L2(μ-SMe)2(μ-L′)]+ cations (L=ButNC, xylNC, CO; L′=SMe or PPh2)

Mixed μ-phosphido or μ-thiolato μ-halo-dimolybdenum(III) compounds [Mo2Cp2(μ-SMe)2(μ-X)(μ-Y)] (X=PPh2, Y=Cl; X=SCH3, Y=Br, I): Electrochemical and structural comparisons – The X-ray structure of [{Mo2Cp2Br(μ-O)(μ-SMe)2}2(μ-MoO4)]

“…The close analogy between the structural characteristics of the triply-bridged {Mo 2 Cp 2 Br(l-SMe) 2 (l-O)} core Table 1 Selected bond lengths (Å ) and angles (°) for the [Mo 2 Cp 2 (l-SMe) 2 (l-X)(l-Y)] complexes 1 (X = PPh 2 ) [6], 2 (X = SMe) [6], 3 (X= SMe) and 4 (X = SMe) a (1) [1][2][3][4]. Though normal electron counting rules require the presence of a Mo-Mo double bond in 5, it is known [8,9] (1) ðl-SMeÞðl-BrÞðl-OÞ is not surprising -see [8,9] (2) and 1.723(2) Å ).…”

“…10.033 framework and the substrate. These considerations led us previously to study (a) the influence of C 5 R 5 rings (R = H, Me) on the electrochemistry and reactivity of {Mo 2 -(C 5 R 5 ) 2 (l-SR) 2 } systems [2] and (b) the effect of terminal L ligands (RNC, CO, RCN) on nucleophilic and electrophilic additions to complex cations of general type [Mo 2 Cp 2 (l-SMe) 3 L 2 ] + [3]. Subsequently, the formation of the l-phosphido compound [Mo 2 Cp 2 (l-SMe) 2 (l-PPh 2 )(lCl)] (1) when [Mo 2 Cp 2 (l-SMe) 3 (l-Cl)] (2) is treated with HPPh 2 [4] allowed us to investigate the effect of varying a single l-X bridging group in bis-cyclopentadienyl derivatives [Mo 2 Cp 2 (l-SMe) 2 (l-X)(l-Cl)] (X = PPh 2 , SCH 3 ).…”

E–H Bond Activation and Insertion Processes in the Reactions of the Unsaturated Hydride [W2Cp2(μ-H)(μ-PPh2)(NO)2]

“…The coordination mode B might be viewed as intermediate between the extreme modes A and C , and indeed the experimental C1–N3 length of 1.347(4) Å in 6 falls midway between the distances typically observed for complexes of types A and C . For comparison, the corresponding C–N length of 1.312(7) Å in the dimolybdenum complex [Mo 2 Cp 2 (μ-κ 1 :κ 1 -HCNXyl)­(μ-SMe) 3 ] (incidentally, the unique group 6 complex of type A structurally characterized to date) is significantly shorter, as expected …”

Reactivity of the metal–cyclopentadienyl (indenyl, fluorenyl and cycloheptatrienyl) bonds

“…Recently, Schollhammer's group examined the reaction of thiolato-bridged binuclear molybdenum complexes [Mo 2 Cp 2 L 2 (l-SMe) 3 ](BF 4 ) (L = XylNC, CO, Bu t ) with a base and anionic reagents, and found that the regioselectivity of nucleophilic reaction remarkably depends on the nature of the co-ligands and anionic reagents [39][40][41]. When L is a good p-acceptor, the anion attacks at the carbon atoms of the Cp favorably, leading to the occurrence of the regioselective protonation or alkylation of the Cp ligand.…”

“…X = LiBu n , NaBH 4 , R = H; L = CO. X = NaBH 4 , R = H; X = RMgCl, R = Me, Pr i , Bu n , Ph; X = LiR, R = Me, Bu n ) [39]. The deprotonation of Mo 2 (g 5 -Cp)(g 4 C 5 H 5 R)-(CO) 2 (l-SMe) 3 affords the functionalized cyclopentadienyl complexes [Mo 2 (g 5 -Cp)(g 5 -C 5 H 4 R)(CO) 2 (l-SMe) 3 ](BF 4 ) (R = Me, Bu n , Ph) (Scheme 8).…”