The present invention provides atrialkoxysilane having structure (I), wherein R1 is independently at each occurrence a C1-C3 alkyl group R3 is independently at each occurrence a hydrogen or a C1-C3 alkyl group R4 is a C1-C5 aliphatic radical, a C7-C12 aromatic radical, or a C5-C10 cycloaliphatic group n is 0, 1, 2 or 3 q is 1, 2 or 3 t is 0, 1 or 2 and X- represents a charge balancing counterion. The trialkoxysilanes are useful for the preparation of nanoparticulate diagnostic imaging agent compositions.
