Cluster coordination: the chemistry of cyclopentadienyl titanium and vanadium complexes with B- and C-functionalized carborane-thiols, [CBH (SH) ] ( = 2 or 3).

A series of B- and C-functionalized di- and trithiol chelating -carborane ligands have been employed to explore the coordination chemistry with cyclopentadienyl titanium and vanadium complexes. Treatment of [CpTiCl] with [LiBH·THF], followed by thermolysis with a C-functionalized carborane-dithiol ligand [1,2-(SH)-1,2-CBH], yielded octacapped octahedral [(CpTi){Ti(1,2-(S)-1,2-CBH)}(μ-S)(μ-O)] (1) and hexacapped trigonal bipyramidal [(CpTi){Ti(1,2-(S)-1,2-CBH)}(μ-S)] (2) clusters. One of the driving forces of these reactions is the cleavage of C-S bonds of carborane-dithiols that resulted in sulfide ligands and subsequently generated clusters 1 and 2. In contrast, a similar reaction with a B-functionalized carborane-dithiol [9,12-(SH)-1,2-CBH] led to B-B bond formation that yielded a κ-hydridoborato complex, [(CpTi){κ-BH(9,12-(S)-1,2-CBH)}] (3). To the best of our knowledge, complex 3 is the first example of a carborane-dithiol functionalized hydridoborato complex. Interestingly, when the reactions of [CpTiCl] or [CpTiCl] were carried out with a B-functionalized carborane-trithiol, [8,9,12-(SH)-1,2-CBH], they led to coordination complexes, [(Cp/CpTi){8,9,12-(S)-1,2-CBH}] (Cp* (4a) and Cp (4b)). Similarly, when [(CpVCl)] was employed as a metal precursor, deboronation was observed at the icosahedral cage that resulted in a zwitterionic complex, [(CpV){1,5,6-(S)--7,8-CBH}] (5). All the clusters have been characterized by NMR, IR, mass spectrometry, and X-ray diffraction analysis. Furthermore, the theoretical analyses provided valuable insights into the electronic structures of these unusual clusters.