Chalcogen stabilized cubane-type cluster: Synthesis and structure of [(Cp*Ta)3(µ-Se)3(µ3- Se)3B(OBuCl)]

Department of Chemistry, Indian Institute of Technology Madras, Chennai-600 036, India

E-mail: sghosh@iitm.ac.in                      Fax: 91-44-22574202

Manuscript received 28 June 2018, accepted 16 July 2018

In an effort to isolate the heavier chalcogen-rich metallaheteroborane analogue of [(Cp*Ta)₃(µ-S)₃(µ₃-S)₃BH], thermolysis of [Cp*TaCl₄] (Cp* = ŋ⁵-C₅Me₅) and Li[BH₂Se₃] was carried out that afforded cubane-type cluster [(Cp*Ta)₃(µ-Se)₃(µ₃- Se)₃B(OBuCl)], 1. Compound 1 is an example of cubane-type organotantalum selenido cluster, in which one of the vertices of the cubane is missing. Compound 1 is a hypo-electronic cluster with an electron count of 50 cve (cve = cluster valence electrons). In parallel to the formation of 1, trimetallic selenide cluster [(Cp*Ta)₃(µ,-Se)₆], 2 has also been isolated and struc­turally characterized. All these compounds were characterized by the multi-nuclear NMR spectroscopy, mass spectrometry and single crystal X-ray crystallography. The density functional theory (DFT) calculations were also performed to provide in­sight into the bonding and electronic structures of these novel clusters.