paper20149

Photocatalytic reduction of CO2 to CO by a dinuclear carbonyl

polypyridyl rhenium(I) complex

Jamaladin Shakeri, Hassan Hadadzadeh ⇑, Hossein Tavakol

Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran

Polyhedron 78 (2014) 112–122

The new dinuclear Re(I) complex, [ReCl(CO)3(l-tptzH)Re(CO)3], where tptzH is 2,4,6-tri(pyridine-2-yl)-

2H-1,3,5-triazine-1-ide has been synthesized and characterized by spectroscopic methods and X-ray

crystallography. During the preparation of the dinuclear complex, a carbon atom of the triazine ring in

the tptz bridging ligand is saturated by two consecutive redox reactions. It is worthy to mention that this

partial saturation of tptz to tptzH is the first example of the saturation of a triazine ring without a nucleophilic

attack. The photocatalytic activity of the dinuclear complex for the photochemical reduction of

CO2 to CO has been also investigated. The photocatalytic reduction of CO2 was carried out in three different

conditions and the turnover number for the CO formation in the TEOA/DMF/NEt4Cl mixture reached a

maximum of 15.8, which was 1.17 and 1.71 times the turnover numbers for the TEA/DMF and TEOA/DMF

mixtures, respectively. The theoretical calculations show that the metal moiety containing the chloro

ligand (ReCl(CO)3) is the most likely active site for the photocatalytic reduction of CO2. Finally, a photocatalytic

cycle was proposed for the reduction of CO2 on the metal moiety containing the chloro ligand.

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