For the d0 complex [{Zr(CpSiMe2H)Cl3}2] which contains a linear Si–H⋯Zr interaction across the dimer, DFT calculations are in good agreement with X-ray structures. The BP86 functional shows a slightly stronger interaction than B3LYP but for qualitative purposes either functional is sufficient. QTAIM analysis shows a bond critical point (bcp) for the interaction, a small negative value for the total energy density [H(r)] and the H atomic basin decreases in energy, E(H), and atomic volume compared to the free ligand. NBO analysis showed E(2) for Si–H σ to Zrdz2 donation at 42.8 kcal mol−1 and a 34% spatial overlap for the interaction consistent with an inverse hydrogen bond. The Wiberg bond index for the interaction is 0.1735 (0.7205 for the Si–H bond), ν(Si–H) and 1J(Si–H) at 2060 cm−1 and 145.4 Hz compared to 2183 cm−1 and 172.1 Hz in the free ligand. Using a “synthesis by computation” approach to forming like complexes, similar features were found for [{Hf(CpSiMe2H)Cl3}2]. The titanium complex [{Ti(CpSiMe2H)Cl3}2] does not contain any Si–H⋯Ti interaction as rotation about the C–Si bond of the ligand occurs to place the Si–H bond hydrogen closer to a terminal chloro ligand across the dimer. An increase in electron density on the metal in the d2 complex [{Mo(CpSiMe2H)Cl3}2] results in a stronger interaction with a distinct QTAIM analysis bcp [ρ(r) 0.0448 a.u.], a small negative value for H(r) and a much reduced H atomic volume. NBO analysis shows E(2) for Si–H σ to Modz2 donation at 143.1 kcal mol−1 and a 29% spatial overlap. Modz2 to Si–H σ* donation (back donation) is minimal [E(2) 1.3 kcal mol−1, ∼1% spatial overlap]. The Wiberg bond index is 0.3114 (0.5667 for the Si–H bond), ν(Si–H) 2015 cm−1 and 1J(Si–H) 120.6 Hz.
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