Electrospray ionization in the study of the polycondensation of Ti(O-i-C3H7)4 and Ti(O-n-C4H9)4

The polycondensation of Ti(O-i-C3H7)4 (1) and Ti(O-n-C4H9)4 (2), precursors widely employed in sol-gel processes, has been investigated by electrospray ionization mass spectrometry. By analysis of 10(-6) M methanol solutions of compounds 1 and 2, the same ionic species are detected, proving that the first step in the polycondensation reaction is the i-propyl (or n-butyl) alcohol-methanol complete exchange. This reaction leads to the Ti(OCH3)4 (3) species, representing the synthon of the polycondensation. Various oligomers of 3 have been detected and characterized by MS/MS experiments, and the related mechanisms have been discussed. A minor oligomeric series due to hydroxyl-containing polycondensation products has also been characterized.