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Synthesis and characterization of molybdenum complexes containing diphosphine ligands of the type (ArCH{sub 2}){sub 2}PC{sub 2}H{sub 4}P(CH{sub 2}Ar){sub 2} (Ar = C{sub 6}H{sub 4}X). Electronic control of {eta}{sup 2}-dihydrogen versus dihydride coordination in MoH{sub 2}(CO)((RCH{sub 2}){sub 2}PC{sub 2}H{sub 4}P(CH{sub 2}R){sub 2}){sub 2} (R = Me, Pr{sup i}, C{sub 6}H{sub 4}X) and implications on the reaction coordinate for H{sub 2} cleavage

Journal Article · · Inorganic Chemistry
; ; ;  [1]
  1. Los Alamos National Lab., NM (United States)

The bis(dinitrogen) molybdenum complexes trans-Mo(N{sub 2}){sub 2}((ArCH{sub 2}){sub 2}PC{sub 2}H{sub 4}P(CH{sub 2}Ar){sub 2}){sub 2} (Ar = C{sub 6}H{sub 5} (1a), C{sub 6}H{sub 4-} m-Me (1b), C{sub 6}H{sub 4}-o-Me (1c), C{sub 6}H{sub 4}-p-Me (1d), C{sub 6}H{sub 4}-o-F (1e), C{sub 6}H{sub 4}-m-F (1f) C{sub 6}H{sub 4}-p-F (1g), C{sub 6}H{sub 4}-m-OMe (1h), C{sub 6}H{sub 4}-p-OMe (1i)) are prepared by reduction of MoCl{sub 5} with magnesium under a dinitrogen atmosphere in the presence of the appropriate diphosphine ligand. Treatment of 1a and 1b with ethyl acetate in refluxing benzene under argon affords the formally 16-electron complexes MoCl{sub 5} with magnesium under a dinitrogen atmosphere in the presence of the appropriate diphosphine ligand. Treatment of 1a and 1b with ethyl acetate in refluxing benzene under argon affords the formally 16-electron complexes Mo(CO)((ArCH{sub 2}){sub 2}PC{sub 2}H{sub 4}P(CH{sub 2}Ar){sub 2}){sub 2} (Ar = C{sub 6}H{sub 5} (2a), C{sub 6}H{sub 4}-m-Me (2b)), which are shown by {sup 1}H NMR spectroscopy to contain an agostic Mo{hor_ellipsis}H-C interaction between the molybdenum and an ortho aryl hydrogen atom. The {eta}{sup 2}-H{sub 2} coordination in 3a and 3b is unambiguously established by IR, NMR, and neutron scattering spectroscopies and a single-crystal X-ray diffraction analysis of 3b. The predisposition toward hydrogen dissociation in these complexes is discussed.

Sponsoring Organization:
USDOE
OSTI ID:
420992
Journal Information:
Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 23 Vol. 33; ISSN 0020-1669; ISSN INOCAJ
Country of Publication:
United States
Language:
English