Abstract
A series of B- and C-functionalized di- and trithiol chelating o-carborane ligands have been employed to explore the coordination chemistry with cyclopentadienyl titanium and vanadium complexes. Treatment of [Cp*TiCl(3)] with [LiBH(4)·THF], followed by thermolysis with a C-functionalized carborane-dithiol ligand [1,2-(SH)(2)-1,2-C(2)B(10)H(10)], yielded octacapped octahedral [(Cp*Ti)(4){Ti(1,2-(S)(2)-1,2-C(2)B(10)H(10))}(2)(μ(3)-S)(6)(μ(3)-O)(2)] (1) and hexacapped trigonal bipyramidal [(Cp*Ti)(4){Ti(1,2-(S)(2)-1,2-C(2)B(10)H(10))}(μ(3)-S)(6)] (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)(2)-1,2-C(2)B(10)H(10)] led to B-B bond formation that yielded a κ(2)-hydridoborato complex, [(Cp*Ti){κ(2)-BH(3)(9,12-(S)(2)-1,2-C(2)B(10)H(10))}] (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 [Cp*TiCl(3)] or [Cp(2)TiCl(2)] were carried out with a B-functionalized carborane-trithiol, [8,9,12-(SH)(3)-1,2-C(2)B(10)H(9)], they led to coordination complexes, [(Cp/Cp*Ti){8,9,12-(S)(3)-1,2-C(2)B(10)H(9)}] (Cp* (4a) and Cp (4b)). Similarly, when [(Cp*VCl(2))(3)] was employed as a metal precursor, deboronation was observed at the icosahedral cage that resulted in a zwitterionic complex, [(Cp*V){1,5,6-(S)(3)-nido-7,8-C(2)B(9)H(9)}] (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.