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

• Published in: New journal of chemistry 2022-10, Vol.46 (38), p.18165-18172
• Main Authors: da Silva, Felipe Dornelles, Bortolotto, Tanize, Tirloni, Bárbara, Daudt, Natália de Freitas, Lang, Ernesto Schulz, Cargnelutti, Roberta
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d2nj02761e

The reactions of bis(2-pyridyl)ditellane (2-PyTe) 2 with cobalt salts (CoCl 2 ·6H 2 O and CoBr 2 ) and CuBr 2 resulted in the formation of three new coordination compounds [Co(2-Py 2 Te 2 -κ N , N ′)Cl 2 ] ( 1 ), [Co(2-Py 2 Te 2 -κ N , N ′)Br 2 ] ( 2 ) and [Cu(2-Py 2 Te 2 -κ N 1 ,Te 2 , N 2′ )Br] 2 ( 3 ), respectively. In compounds 1 and 2 , the ligand 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-Py 2 TeClO-κ O , N , N ′)Cl] 2 ( 4 ) was formed using bis(2-pyridyl)ditellane as a precursor. After the generation of bis(2-pyridyl)tellane (2-PyTePy-2) in situ , CuCl 2 ·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 ligand [2-Py 2 Te(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 photocatalysts TiO 2 - 1 and TiO 2 - 2 were prepared and tested for hydrogen evolution from water splitting, using a 300 W Hg/Xe lamp as the irradiation source. Both photocatalysts have produced higher amounts of hydrogen when compared with pure TiO 2 , suggesting that compounds 1 and 2 perform as effective photosensitizers. Coordination compounds containing bis(2-pyridyl)ditellane as a precursor and transition metals are described. The cobalt-containing photocatalysts are active for H 2 production.