Bis(2-pyridyl)ditellane as a precursor to CoII, CuI and CuII complex formation: structural characterization and photocatalytic studies

The reactions of bis(2-pyridypditellane (2-PyTe)(2) with cobalt salts (CoCl2 center dot 6H(2)O and CoBr2) and CuBr2 resulted in the formation of three new coordination compounds [Co(2-Py2Te2-kappa N, N')Cl-2] (1), [Co(2-Py2Te2-kappa N, N')Br-2] (2) and [Cu(2-Py2Te2-kappa N-1, Te-2, N-2')Br](2) (3), respectively. In compounds 1 and 2, the Eigand is coordinated to cobalt(II) through the nitrogen atoms of the pyridyl groups. On the other hand, in compound 3, the coordination of the soft tellurium donor atom to the soft copper(I) metal center was also observed. Compound [Cu(2-Py2TeClO-kappa O, N, N')Cl](2) (4) was formed using bis(2-pyridypditellane as a precursor. After the generation of bis(2-pyridyptellane (2-PyTePy-2) in situ, CuCl2 center dot 2H(2)O was added in DMSO. During the reaction, the tellurium atom was oxidized from +2 to +4, with the formation of the anionic Eigand [2-Py2Te(Cl)(O)](-). All compounds 1-4 were characterized using spectroscopic techniques and single-crystal X-ray diffraction. Diffuse reflectance spectroscopy data were used to estimate the band gap energies of the compounds. The photocataIysts TiO2-1 and TiO2-2 were prepared and tested for hydrogen evolution from water splitting, using a 300 W Hg/Xe lamp as the irradiation source. Both photocataIysts have produced higher amounts of hydrogen when compared with pure TiO2, suggesting that compounds 1 and 2 perform as effective photosensitizers.

Automated summary

Three new coordination compounds were synthesized by the reactions of bis(2-pyridypditellane) with cobalt salts and copper salt. These compounds exhibit different coordination modes and properties. Compounds 1 and 2 show potential as effective photosensitizers for hydrogen evolution from water splitting.