Chisholm MH, Davidson ER, Pink M, Quinlan KB. Tristhiolatomolybdenum nitrides, (RS)(3)Mo[triple bond]N where R = (i)Pr and (t)Bu, preparation, characterization and comparisons with related trialkoxymolybdenumnitrides.
Inorg Chem 2002;
41:3437-43. [PMID:
12079462 DOI:
10.1021/ic020106q]
[Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The addition of thiols to ((t)BuO)(3)Mo[triple bond]N in toluene leads to the formation of (RS)(3)Mo[triple bond]N compounds as yellow, air-sensitive compounds, where R = (i)Pr and (t)Bu. The single-crystal structure of ((t)BuS)(3)Mo[triple bond]N reveals a weakly associated dimeric structure where two ((t)BuS)(3)Mo[triple bond]N units (Mo-N = 1.61 A, Mo-S = 2.31 A (av)) are linked via thiolate sulfur bridges with long 3.03 A (av) Mo-S interactions. Density functional theory calculations employing Gaussian 98 B3LYP (LANL2DZ for Mo and 6-31G* for N, O, S, and H) have been carried out for model compounds (HE)(3)Mo[triple bond]N and (HE)(3)MoNO, where E = O and S. A comparison of the structure and bonding within the related series ((t)BuE)(3)Mo[triple bond]N and ((t)BuE)(3)MoNO is made for E = O and S. In the thiolate compounds, the highest energy orbitals are sulfur lone-pair combinations. In the alkoxides, the HOMO is the N 2p lone-pair which has M-N sigma and M-O pi* character for the nitride. As a result of greater O p pi to Mo pi interactions, the M-N pi orbitals of the Mo-N triple bond are destabilized with respect to their thiolate counterpart. For the nitrosyl compounds, the greater O p pi to Mo d pi interaction favors greater back-bonding to the nitrosyl pi* orbitals for the alkoxides relative to the thiolates. The results of the calculations are correlated with the observed structural features and spectroscopic properties of the related alkoxide and thiolate compounds.
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