ESI-MS studies of palladium (II) complexes with 1-(p-toluenesulfonyl)cytosine/cytosinato ligands.

The mononuclear complex Pd(1-TosC-N3)(2)Cl(2) (2) containing 1-(p-toluenesulfonyl)cytosine (1) as a ligand, as well as dinuclear complexes Pd(2)(1-TosC(-)-N3,N4)(4) (3) and Pd(2)(1-TosC(-)-N3,N4)(2)DMSO(2)Cl(2) (4) containing the ligand anion (1-TosC(-)), was mass analyzed by electrospray ionization ion trap MS/MS and high resolution MS. Complexes 3 and 4 were obtained by recrystallization of 2 from DMF and DMSO, respectively. The behavior of complex 2 in different solutions was monitored by electrospray ionization mass spectrometry (ESI-MS). Under the applied ESI-MS conditions, complex 2 in methanol reorganized itself dominantly as new complex 3 and the solvent did not coordinate the formed species. In H(2)O/DMSO, CH(3)CN/DMSO and CH(3)OH/DMSO solutions, complex 2 formed several new species with solvent molecules involved in their structure, e.g. complex 4 was formed as the major product. The newly formed species were also examined by LC-MS-DAD, confirming the solvent induced reorganization and the solution instability of complex 2. Copyright 2009 John Wiley & Sons, Ltd.