PHOTOCHEMISTRY OF (TRANS-4-STYRYLPYRIDINE)METHYL(TRIOXO)RHENIUM(VII) - PHOTOASSISTED ISOMERIZATION OF 4-STYRYLPYRIDINE

The reflectance spectrum of solid MeReO3(trans-4-styrylpyridine) shows a long-wavelength band (lambda(max) = 342 nm) with vibrational struct ure. This band is assigned to an intraligand transition of the coordin ated styrylpyridine. In solution (e.g. CH2Cl2) the complex largely dis sociates into MeReO3 and styrylpyridine which displays a broad absorpt ion at lambda(max) = 308 nm. Irradiation with 366 nm light leads to se lective excitation of residual amounts of intact MeReO3(trans-4-styryl pyridine) which undergoes a complete trans-to-cis photoisomerization o f the coordinated ligand. Owing to the kinetic lability of MeReO3(tran s-4-styrylpyridine) this photolysis proceeds as a photoassisted reacti on of 4-styrylpyridine. (C) 1997 Elsevier Science S.A.