ELECTROSPRAY-IONIZATION ION-TRAP MASS-SPECTROMETRY OF A TETRAHEDRAL SUPRAMOLECULAR TI4L4 CLUSTER

The analysis of self-assembled supramolecular clusters held together b y metal-ligand interactions is a relatively new area in mass spectrome try. These complexes may have molecular weights exceeding several kDa, are often highly charged and their composition is most sensitive to t heir chemical environment. Electrospray ionization appears to be the i onization technique of choice for their mass spectral characterization . The analysis (positive and negative ion detection mode) of the proto type compound [Ti-4 L-4](8-) (L = a catechol-based tris-bidentate liga nd; MW of cluster = 2293 u) using a Paul trap mass analyzer is reporte d. The combination of electrospray ionization and high resolution ion trap technology is a powerful tool which provides the unambiguous solu tion state characterization of this supramolecular cluster. The result s are correlated with the known solid state structure of the cluster a nd reactions previously reported for mononuclear Ti(IV) catecholates. (C) 1998 American Society for Mass Spectrometry.