[M(1,2-dap)₃][B₁₀O₁₃(OH)₆] (M = Co, Ni): Two New Borates Containing [B₁₀O₁₃(OH)₆]²⁻ Cluster Units

Two novel isomorphic decaborates, [M(1,2-dap)₃][B₁₀O₁₃(OH)₆] (M = Co (1) and Ni (2); dap = 1,2-diaminopropane), with transition metal complexes [M(1,2-dap)₃] as templates have been synthesized successfully under mild hydrothermal conditions and characterized by powder X-ray diffraction, thermogravimetric analysis, IR spectrum, single crystal X-ray diffraction and UV–Vis spectroscopy. The noodle-like orange/purple crystals crystallize in triclinic space group P-1. Their structure contain the isolated [B₁₀O₁₃(OH)₆]²⁻ clusters and further link together to produce a 3-D supramolecular framework with large channels by H-bonding interactions. The UV–Vis–NIR diffuse reflectance spectrum showed a wide-band-gap of 1 and 2. Notice that compounds 1 and 2 are not only the first isolated decaborate cluster and fill the gap left by the absence of isolated structures in the borate family but also could be considered as the structural building units to construct extended oxoboron cluster frameworks.