| Abstract
| - Intermolecular associations for (tBuE)3MoN compounds occur via N−Mo donation for E = O and S−Mo donation for E = S, which correlates well with electronic structure calculations.
- The addition of thiols to (tBuO)3Mo⋮N in toluene leads to the formation of (RS)3Mo⋮N compounds as yellow,air-sensitive compounds, where R = iPr and tBu. The single-crystal structure of (tBuS)3Mo⋮N reveals a weaklyassociated dimeric structure where two (tBuS)3Mo⋮N units (MoN = 1.61 Å, MoS = 2.31 Å (av)) are linkedvia thiolate sulfur bridges with long 3.03 Å (av) Mo−S interactions. Density functional theory calculations employingGaussian 98 B3LYP (LANL2DZ for Mo and 6-31G* for N, O, S, and H) have been carried out for model compounds(HE)3Mo⋮N and (HE)3MoNO, where E = O and S. A comparison of the structure and bonding within the relatedseries (tBuE)3Mo⋮N and (tBuE)3MoNO is made for E = O and S. In the thiolate compounds, the highest energyorbitals are sulfur lone-pair combinations. In the alkoxides, the HOMO is the N 2p lone-pair which has MN σ andMO π* character for the nitride. As a result of greater O pπ to Mo π interactions, the MN π orbitals of theMoN triple bond are destabilized with respect to their thiolate counterpart. For the nitrosyl compounds, the greaterO pπ to Mo dπ interaction favors greater back-bonding to the nitrosyl π* orbitals for the alkoxides relative to thethiolates. The results of the calculations are correlated with the observed structural features and spectroscopicproperties of the related alkoxide and thiolate compounds.
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