Multiple-imido complexes of molybdenum: Synthesis and reactivity of the d{sup 0} Mo(=NR){sub 3} functional group
- Univ. of Arizona, Tucson, AZ (United States)
Red-orange crystals of the tris(imido) anion of molybdenum, [Mo(NAr){sub 3}Cl]{sup {minus}} (3, Ar=2,6-C{sub 6}H{sub 3}-i-Pr{sub 2}) are isolated as the [Li(THF){sub 4}]{sup +} salt from the rapid workup of the reaction between Mo(NAr){sub 2}Cl{sub 2}(THF){sub 2} (1) and 2 equiv of LiNHAr (in THF). [Li(THR){sub 4}][Mo(NAr){sub 3}Cl] (3) constitutes the kinetic product of this reaction since it readily reacts with byproduct H{sub 2}NAr to afford stable Mo(NAr){sub 2}(NHAr){sub 2} (4). Complex 3 undergoes nucleophilic attack by PMe{sub 3}, MeLi, Me{sub 3}CCH{sub 2}Li, or Br{sup {minus}} to form Mo(NAr){sub 3}(PMe{sub 3}) (5), [Li(THF){sub 4}][Mo(NAr){sub 3}Me] (6), [Li(THF){sub 4}]-[Mo(NAr){sub 3}(CH{sub 2}CMe{sub 3})] (7), and [n-Bu{sub 4}N][Mo(NAr){sub 3}Br] (8), respectively. The imido ligands in these tris(imido) complexes are also subject to electrophilic attach by a range of electrophiles to afford four- or five-coordinate bis(imido) complexes of Mo(VI). Thus, MO(NAr){sub 2}(OCMe{sub 3}){sub 2} (9) is prepared form Mo(NAr){sub 3}(PMe{sub 3}) (5) and Me{sub 3}-COH, while metallacyclic Mo[NArC(O)NPh](NAr){sub 2}(PMe{sub 3}) (10) arises form Mo(NAr){sub 3}(PMe{sub 3}) (5) and PhNCO, [Li(THF){sub 4}][Mo(NAr){sub 3}Cl] (3) is readily protonated by cyclopentadiene C{sub 5}H{sub 6} to provide CpMo(NAr){sub 2}(NHAr) (11, Cp = {eta}{sup 5}-C{sub 5}H{sub 5}{sup {minus}}). The reaction of [HNMe{sub 3}]BPh{sub 4} with [Li(THF){sub 4}][Mo(NAr){sub 3}(CH{sub 2}CMe{sub 3})] (7) protonates an imido ligand rather than the alkyl to give Mo(NAr){sub 2}(NHAr)(CH{sub 2}CMe{sub 3}) (12). The electronic structure of the d{sup 0} Mo(=NR){sub 3} functional group is described in terms of related M({sigma}+2{pi}){sub 3} complexes with 3-fold symmetry.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG03-93ER14349
- OSTI ID:
- 458747
- Journal Information:
- Inorganic Chemistry, Vol. 34, Issue 10; Other Information: PBD: 10 May 1995
- Country of Publication:
- United States
- Language:
- English
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