CONJUGATED PYRIDINES WITH AN END-CAPPING FERROCENE

This study reports the synthesis of new pyridyl ligands incorporating an alkyne entity with an end-capping ferrocenyl moiety: -(ferrocenylet hynyl)-4-((4-pyridyl)ethynyl)benzene (FEPEB), 1-ferrocenyl-6-(4-pyridy l)hexatriyn (FPHT), and 1-ferrocenyl-4-(4-pyridyl)butadiyne (FPBD). Th e complexes W(CO)(4)(L)(FEPEB) (L = CO, PPh(3), P(OMe)(3), PMe(3)), W( CO)(4)(L)(FPHT) (L = CO, PPh(3), P(OMe)(3), PMe(3)), and W(CO)(5)(FPBD ) are obtained by ligating FEPEB, FPHT, and FPBD to W(CO)(4)(L)(THF). The energy of tungsten metal to pyridyl pi charge transfer (MLCT) dep ends an both the pyridyl ligand and the ancillary ligand, L, Treating FPHT and FPBD with Mel causes N-methylpyridinium derivatives to form, which exhibit a strong low-lying charge-transfer band. As a comparativ e study, the complexes rocenylethynyl)-4-((4-nitrophenyl)ethynyl)-benz ene (FENEB) and rrocenylethynyl)-4-((4-aminophenyl)ethynyl)benzene (FE AEB) have also been synthesized. X-ray analysis has been employed to e xamine the structures of 1-(ferrocenylethynyl)-4-ethynylbenzene, W(CO) (4)(PPh(3))(FEPEB), W(CO)(5)(FPHT), and 1,8-diferracenyloctatetrayne.