Synthesis of electroactive multinuclear dipyrrinato complexes and Fe(III) assisted formation of α-alkoxy substituted 5-ferrocenyldipyrromethenes.

The synthesis and characterization of multinuclear complexes [Pd(acac)(fcdpm)] (1), [Pd(fcdpm)(2)] (2), [Co(acac)(fcdpm)(2)] (3), [Co(fcdpm)(3)] (4) and α-alkoxy derivatives [α-OMe-fcdpm] (5), [α-OEt-fcdpm] (6), [α-OPr(n)-fcdpm] (7) and [α-OBu(n)-fcdpm] (8) (fcdpm = 5-ferrocenyldipyrromethene; acac = acetylacetone) have been described. Formation of alkoxy derivatives 5-8 takes place from highly selective Fe(III) mediated alkoxylation of fcdpm in alcohol. It has been established that yield of α-alkoxy derivatives depend on the alcohol chain length. The compounds under study have been characterized by elemental analyses, spectral (IR, (1)H, (13)C NMR, ESI-MS, UV-vis) and electrochemical studies (CV and DPV). Structures of 1, 3 and 5 have been verified by X-ray single crystal analyses. Structural studies revealed distorted square planar and octahedral geometry about Pd(II) and Co(III) centres. All the compounds exhibited oxidation wave due to Fc/Fc(+) redox couple (0.34-0.36, 1-4; 0.24-0.25 V, 5-8).