Hydrothermal synthesis and structural characterization of a new 2D inorganic–organic hybrid compound based on {Ni6PW9}2 subunit

A new two-dimensional (2D) inorganic–organic hybrid compound H2{[Ni6(μ3-OH)3(H2O)4(en)(CH3COO)(IN)(B-PW9O34)]}·2H2O (en = ethylenediamine; HIN = isonicotinic acid) (1) has been hydrothermally synthesized and characterized by IR spectrum, electrochemical measurements, diffuse reflectance UV–vis spectrum and single-crystal X-ray diffraction. Compound 1 contains a nanometer-scale secondary building unit (SBU) [Ni6(μ3-OH)3(B-α-PW9O34)]2 ({Ni6PW9}2), in which two {Ni6PW9} units are linked together through Ni–O–W linkages. The adjacent SBUs are connected by IN and forming a 2D layer network. 1 exhibits semiconducting properties with the band gap Eg at 1.98 eV.