A series of Ti(IV)/Ti(III) coordination polymers: structures and surface photoelectric properties.

Three titanium coordination polymers, {[Ti(SO4)2(H2O)]·0.5bipy·2H2O}n 1, {[Ti1(SO4)2(H2O)]·[Ti2(SO4)2(H2O)]·bipy·5H2O}n 2 and [Ti(tea)]n 3 (bipy=4,4′-bipyridine, H3tea=triethanolamine) were synthesized and characterized by IR, UV–Vis absorption spectra, TG analysis, X-ray single crystal diffraction and surface photovoltage spectroscopy (SPS). The surface photoelectric properties of titanium coordination polymers were discussed emphatically by the SPS. The results of single crystal diffraction indicate that polymers 1 and 2 possess 1D infinite structure bridged by SO42− groups and coordinated water molecules and further connected into supramolecular structures by hydrogen bonds. Polymer 3 possesses 2D infinite structure bridged by weak sub-coordinated Ti–O bonds. The results of SPS show that there are obvious photovoltage responses in the range of 300–500nm, which indicates that they possess photoelectric conversion ability. The SPS of three titanium polymers were analyzed comparatively. It is found that the valence of central metal ions, coordination micro-environment and kinds of coordination atoms influence the results of the SPS. The SPS is associated with UV–Vis absorption spectra.