Two-Coordinate, Nonlinear Vanadium(II) and Chromium(II) Complexes of the Silylamide Ligand–N(SiMePh₂)₂: Characterization and Confirmation of Orbitally Quenched Magnetic Moments in Complexes with Sub‑d⁵ Electron Configurations

The two-coordinate metal amide complexes V­{N­(SiMePh₂)₂}₂ (1) and Cr­{N­(SiMe₂Ph)₂}₂ (2) were synthesized by reaction of two equivalents of LiN­(SiMePh₂)₂ with VI₂(THF)₄ or CrCl₂(THF)₂ in n-hexane. Their crystal structures showed that they have bent coordination, N–V–N = 137.0(4)°, N–Cr–N = 139.19(5)°, at the metals. The vanadium complex (1) displayed no tendency to isomerize as previously observed for some V­(II) amido complexes. Curie fits of SQUID magnetic measurements afforded magnetic moments of 3.36 (1) and 4.68 (2) μ_B, consistent with high-spin configurations. These values are lower than the spin-only values of 3.88 and 4.90 μ_B expected for d³ and d⁴ complexes, suggesting a significant unquenched orbital angular momentum contribution to the overall moment, which is lower as a result of the positive spin–orbit coupling constants.