ELECTROSPRAY-IONIZATION OF DIVALENT TRANSITION-METAL ION BIPYRIDINE COMPLEXES - SPECTROSCOPIC EVIDENCE FOR PREPARATION OF SOLUTION ANALOGS IN THE GAS-PHASE

Laser photofragmentation mass spectrometry provides die first spectros copic evidence that electrospray ionization (ESI) produces gas-phase c lusters containing transition metal ion complexes analogous to those f ound in solution, In solution, the tris(2,2'-bipyridyl)iron(II) and ru thenium(II) coordination complexes exhibit strong metal-to-ligand char ge transfer (MLCT) absorption bands in the visible. The characteristic MLCT absorption bands are intact in gas-phase methanolic clusters con taining these complexes, indicating that the metal oxidation state is preserved during ESI. Comparison of the ionic species produced by ESI and other ionization/volatilization techniques offers some insight on stabilization of the + 2 charge in these gas-phase systems.