ИСТИНА

In this lecture, we inspect the known structures of d-block metal tetrahydroborate complexes and their spectral properties obtained experimentally along with DFT calculations to elaborate the criteria for κ1,2-BH4 complexes demarcation as a particular class between κ1- and κ2-coordinated BH4 ligands. Besides a variety of the BH4−ligand coordination modes another peculiarity of transition metal tetrahydroborate complexes is the presence of several types of hydride ligands (MH, BHterm, BHbr). That leads to a variety of mono-, bi-, and trifurcate dihydrogen bonded complexes, but only a few of them are the proton transfer reaction intermediates [1-5]. Our investigations on the reactivity of [BH4]− and transition metals (Cu, Ru, Pd) tetrahydroborate and hydridotetrahydroborate complexes in the presence of alcohols by variable-temperature IR, UV-vis, and NMR spectroscopes in combination with DFT calculations revealed that the nature (Lewis acidity/basicity) of transition metal in borohydride complexes is the major determinant for the overall mechanism of the borohydride fragment activation.