SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES OF P,P'-DI[3-(TRIMETHYLSILYL)-1-PROPYL] METHYLENEDIPHOSPHONIC ACID

摘要

The silicon-substituted diphosphonic acid P,P'-dr[3-(trimethylsilyl)-1-propyl] methylenediphosphonic acid, H_2DTMSP-[MDP], reacts with metal nitrates in methanol to form complexes M_2(DTMSP[MDP])_3 for M = Fe, Eu and Yb and M(DTMSP(MDP))_2 for M - Th. The sodium salt, Na_2-(DTMSP[MDP]), forms upon neutralization of H_2DTMSP-[MDP] with NaOH. The calcium salt, Ca(DTMSP[MDP]), forms upon addition of the aqueous metal nitrate to an equivalent amount of the neutralized ligand in methanol. Elemental analysis, infrared spectroscopy and magnetic susceptibility measurements were used to characterize the compounds. Frequency shifts in the asymmetric and symmetric POO~- stretching bands of the Fe, Eu, Yb and Th compounds indicate symmetrical coordination of the hposphonate groups through chelate and/or bridging interactions. The frequency difference between these stretching bands becomes smaller as the ionic potential (e/r) of the metal ion increases.