Two-dimensional [sup 1]H-NMR EXSY study of the fluxional behavior of the novel carbenium ion complex [FvMo[sub 2](CO)[sub 4]([mu],[eta][sup 2],[eta][sup 3]-MeC[equivalent to]CCH[sub 2])][BF[sub 4]] (Fv = Fulvalene). Syntheses, structures, and reactivity

Journal Article · Mon Mar 01 00:00:00 EST 1993 · Organometallics; (United States)

DOI:https://doi.org/10.1021/om00027a005· OSTI ID:5989498

Amouri, H E; Besace, Y; Vollhardt, K P.C.; Ball, G E ^[1]; Vaissermann, J ^[2]

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1. Univ. of California, Berkeley (United States) Lawrence Berkeley Lab., CA (United States)
2. Universite Pierre et Marie Curie, Paris (France)

The title compound [FuMo[sub 2](CO)[sub 4]([mu],[eta][sup 2],[eta][sup 3]-MeC[equivalent to]CCH[sub 2])][BF[sub 4]] (3) was obtained quantitatively by protonation of [FvMo[sub 2](CO)[sub 4][mu],[eta][sup 2],[eta][sup 2]-MeC[equivalent to]CCH[sub 2]OMe] (2) in ether solution. In solution 3 was found to be fluxional. The mechanism of exchange was elucidated by 2-D [sup 1]H NMR EXSY (exchange spectroscopy), and the rate constants were determined with k[sub int] = 35 [+-] 4 s[sup [minus]1], [delta]G[double dagger]70[degrees]C = 17.7 [+-] 0.4 kcal/mol and k[sub rot] = 5 [+-] 0.5 s[sup [minus]1], [Delta]70[degrees]C = 19.1 [+-] 0.4 kcal/mol (int = interconversion; rot = rotation). Consistent with this fluxional behavior the molecular structure of 3, ascertained by X-ray analysis, showed a dynamic disorder in the solid state for the bridged hydrocarbyl ligand as well as for the carbonyl groups. [FvMo[sub 2](CO)[sub 4]([mu],[eta][sup 2],[eta][sup 3]-MeC[equivalent to]CCH[sub 2])]BF[sub 4] (3) crystallizes in the monoclinic space group P2[sub 1]/n with Z = 4 and cell dimensions a = 8.546 (3), b = 26.4441 (14), and c = 8.619 (2) [angstrom] and [beta] = 105.73 (2)[degrees]. The reactivity of this carbenium ion complex with respect to various nucleophiles is reported, including the X-ray molecular structure of the phosphonium derivative FvMo[sub 2](CO)[sub 4][mu],[eta][sup 2],[eta][sup 2]-MeC[equivalent to]CCH[sub 2]PPh[sub 3][BF[sub 4]] (6) obtained from phosphine addition to 3. Compound 6 crystallizes in the monoclinic space group P2[sub 1]/c with Z = 8 and cell dimensions a = 13.243 (4) b = 13.243 (4), and c = 38.461 (4) [angstrom] and [beta] = 93.92 (2)[degrees]; the structure was refined to R and R[sub w] values of 4.3 and 5.0%, respectively, using 6606 reflections. 16 refs., 3 figs.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5989498
• Journal Information: Organometallics; (United States), Vol. 12:3; ISSN 0276-7333
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
MOLYBDENUM COMPLEXES
CHEMICAL REACTIONS
MOLECULAR STRUCTURE
SYNTHESIS
BORON COMPLEXES
CRYSTALLIZATION
LIGANDS
NUCLEAR MAGNETIC RESONANCE
REACTION KINETICS
COMPLEXES
KINETICS
MAGNETIC RESONANCE
PHASE TRANSFORMATIONS
RESONANCE
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties
360602 - Other Materials- Structure & Phase Studies