Homo- and heterobimetallic azines derived from ferrocene and cyrhetrene: Synthesis, structural characterization and electrochemical studies.

Abstract A new series of asymmetrical heterobimetallic azines [(η5-C 5 H 5)Fe{(η5-C 5 H 4) C(R) = N N C(R1)-(η5-C 5 H 4)Re(CO) 3 }] (1–3) and symmetrical homobimetallic cyrhetrenyl azines [{(η5-C 5 H 4) C(R) = N}Re(CO) 3 ] 2 (4 , 5) have been synthesized and were spectroscopically characterized by FT-IR, NMR, EI-MS and cyclic voltammetry. The molecular structures of 1 and 4 were determined using single-crystal X-ray diffraction technique. Based on the oxidation potential of the ferrocenyl units and the high degree of planarity of the [(C 5 H 4) C(H) = N N C(H)-(C 5 H 4)] system in complex 1 , we inferred electronic communication between the electron-withdrawing cyrhetrenyl groups through the π-conjugated azine bridge. The compounds display an (E,E)-configuration about the >C N- bond, an s-trans conformation for the N N bond and an anti -conformation for the two organometallic fragments. Graphical abstract The synthesis of new organometallic symmetrical homo- and unsymmetrical hetero-bimetallic azines containing a ferrocenyl and cyrhetrenyl moieties are described. Electronic communication between the organometallic fragments was assigned on the bases of E 1/2 and coplanarity of the [(C 5 H 4) C(H) = N N C(H)-(C 5 H 4)] system. Image 1 Highlights • Homo- and hetero-bimetallic azines containing cyrhetrene and ferrocene were synthesized and characterized. • E 1/2 and coplanarity of the [(C5H4)-C(H)=N-N=C(H)-(C5H4)] system indicate electronic communication. • Compounds exhibit E,E isomerism, s-trans conformation of the N-N bond and anti -conformation. [ABSTRACT FROM AUTHOR]