Synthesis, characterization and crystal structures of mono-, di- and trinuclear rhenium(I) tricarbonyl complexes with 2,3,5,6-tetra(2-pyridyl)pyrazine

✍ Scribed by Xiaoyuan Chen; Frank J Femia; John W Babich; Jon Zubieta

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 143 KB
• Volume: 315
• Category: Article
• ISSN: 0020-1693
• DOI: 10.1016/s0020-1693(01)00335-8

✦ Synopsis

A series of rhenium(I) tricarbonyl complexes with the ligand 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) were synthesized and characterized crystallographically. Two different coordination modes were found when tppz functions as a monobidentate ligand. Rhenium(I) may be bound to tppz through pyrazine and pyridyl nitrogens completing a 5-membered coordination ring when the reaction was carried out in toluene. However, the same reaction in methanol produced a yellow complex in which rhenium(I) was bound to tppz through two adjacent pyridyl nitrogens with a 7-membered coordination ring. In the presence of an excess amount of [ReBr(CO) 5 ], the dinuclear complex [{ReBr(CO) 3 } 2 (m-tppz)] (3) was isolated, while the trinuclear complex [{ReCl(CO) 3 } 3 -(m-tppz)] (4) was obtained in the case of [ReCl(CO) 5 ].