A Three-Coordinate and Quadruply Bonded Mo−Mo Complex

Abstract

Reaction of MoCl3(THF)3 with [Me2Si{NLi(Dipp)}2]2 (Dipp = 2,6-i-PrC6H3) afforded a triply bonded dimolybdenum complex 1,2-Mo2Cl2[Me2Si(NDipp)2]2 1, spanned by two Me2Si[N(Dipp)]2 ligands, thus resulting in a syn conformation. The air- and moisture-sensitive compound 1 was characterized by NMR spectroscopic, elemental, and single-crystal X-ray crystallographic analysis. Reduction of 1 by Na/Hg yielded the quadruply bonded dimeric complex Mo2[Me2Si(NDipp)2]2 2, which was also characterized by the aforementioned analytical methods. The Mo-Mo bond was determined to be 2.1784(12) A, which is considered a long quadruple bond. In addition, density functional theory (DFT) computations on compound 2 provided insight into the intriguing Mo-Mo quadruple bond.

Experimental and Theoretical Studies on Arene‐Bridged Metal–Metal‐Bonded Dimolybdenum Complexes

“…Despite the time that has elapsed and the spectacular development experienced by the field,2 interesting discoveries continue to be made. The quadruple MoMo bond has been intensively investigated 2–5. Its dimetal unit with a σ 2 π 4 δ 2 electron configuration is redox active and suitable to study mixed valency 4.…”

Stepwise Construction of the CrCr Quintuple Bond and Its Destruction upon Axial Coordination

“…Fortunately, the formulation of 5 and 6 was corroborated by X-ray crystallography, [7] and their molecular structures are depicted in Figure 3 [6]). Unlike 3 and 4 and their striking structural difference, compounds 5 and 6 display strongly similar structures.…”

“…Based on their structures, these quintuple-bonded dinuclear compounds can be simply classified into two types as illustrated in Figure 1. For example, the d bonds in the quintuple-bonded species [Mo 2 {m-h 2 -RC(N-2,6-iPr 2 C 6 H 3 ) 2 } 2 ] (R = H, Ph) [3h] and quadruple-bonded complex [Mo 2 {m-h 2 -Me 2 Si(N-2,6-iPr 2 C 6 H 3 ) 2 } 2 ] [6] are formed by alkali metal reduction of the corresponding chloride-coordinated quadrupleand triple-bonded species, respectively. [4] Preliminary reactivity studies on the type I complexes show that they are reactive towards the activation of small molecules and display interesting complexation with olefins and alkynes.…”

“…For example, the d bonds in the quintuple-bonded species [Mo 2 {m-h 2 -RC(N-2,6-iPr 2 C 6 H 3 ) 2 } 2 ] (R = H, Ph) [3h] and quadruple-bonded complex [Mo 2 {m-h 2 -Me 2 Si(N-2,6-iPr 2 C 6 H 3 ) 2 } 2 ] [6] are formed by alkali metal reduction of the corresponding chloride-coordinated quadrupleand triple-bonded species, respectively. It should be noted that all these precursors lack Cr À Cr bonding.…”

Syntheses and Crystal Structures of Novel Functionalized Lithium Silylamides R(4–n)Si(N(Li)CH2CH2NR'2)n (R = Me, Ph, R' = Me, iPr; n = 2, 3)

“…Novel applications for instance comprise silylamides as supporting ligands for complexes with metal-metal single and multiple bonds. [3,4] Moreover, the use of functionalized silylamide ligands bearing additional donor groups has opened new perspectives in coordination chemistry in particular concerning the stabilization of transition metal dinitrogen complexes [5] and lanthanoid metal alkyl complexes. [6] 2-with X = NMe 2 or OMe.…”