The general synthesis of heteroleptic acyclic silylenes with a bulky carbazolyl substituent (dtbpCbz) is detailed and a series of compounds with a chalcogenide substituent of the type [(dtbpCbz)SiE16R] (E16R = OtBu, SEt, SePh, TePh) is reported. With the bulky carbazolyl substituent present, the chalcogenide moiety can be very small, as is shown by incorporating groups as small as ethyl, phenyl or tert‐butyl. For the first time, the electronic properties of the silylene can be tuned along a complete series of chalcogenide substituents. The effects are clearly visible in the NMR and UV/vis spectra, and were rationalised by DFT computations. The reactivity of the heaviest chalcogenide‐substituted silylenes was probed by reactions with trimethylphosphine selenide and the terphenyl azide TerN3 (Ter = 2,6‐dimesitylphenyl).
The reaction of [tBuN=VCp(PMe3)2] (1) with S8, Se, Te or I2 have been studied. Via this pathway dinuclear diamagnetic tert-butylimidovanadium(IV) complexes are formed: [(μ-E)(μ- NtBu)2V2Cp2] (E=S, Se, Te), [(μ-η1−E2)(μ-NtBu)2V2Cp2] E=Se (3), Te}, [(μ-NtBu)2V2Cp2I2]. In addition the vanadium(V) complexes [tBuN=VCp (S5)] (9a) and tBuN=VCpI2 could be isolated. The synthesis of tBuN=VCpF2 is also described. All compounds obtained have been characterized by spectroscopic methods (MS; 1H, 13C, 51V NMR), 3 and 9b by single crystal X-ray diffraction analysis.