unless otherwise stated , all chemicals and solvents were purchased from commercial suppliers in reagent- or technical - grade quality and used directly as received without further purification . the bis(arylimino)acenaphthene ligands were prepared from acenaphthenequinone and the corresponding substituted anilines in anology to literature methods.[14 , 27 ] the rhenium complex 1 was synthesized as previously reported . general procedure for the preparation of 2 and 3 : equimolar amounts of re(co)5cl ( 0.05 g , 0.14 mmol ) and the corresponding bis(arylimino)acenaphtene ligand were refluxed in dry toluene ( 4 ml ) for 30 min . complete precipitation of the product was obtained upon cooling the reaction mixture to room temperature and slow addition of n - hexane . as a service to our authors and readers , this journal provides supporting information supplied by the authors . such materials are peer reviewed and may be re - organized for online delivery , but are not copy - edited or typeset . technical support issues arising from supporting information ( other than missing files ) should be addressed to the authors
rhenium(i ) carbonyl complexes carrying substituted bis(arylimino)acenaphthene ligands ( bian - r ) have been tested as potential catalysts for the two - electron reduction of carbon dioxide . 
 cyclic voltammetric studies as well as controlled potential electrolysis experiments were performed using co2-saturated solutions of the complexes in acetonitrile and acetonitrile  water mixtures . 
 faradaic efficiencies of more than 30 % have been determined for the electrocatalytic production of co. the effects of ligand substitution patterns and water content of the reaction medium on the catalytic performance of the new catalysts are discussed .