Synthesis, Crystal Structures, and Solution Properties ofN-Methylene(phenyl)phosphinic Acid Derivatives of Cyclen and Cyclam

Determination of microscopic acid?base parameters from NMR?pH titrations

“…For instance, the protonation of phosphates leads to an upfield shift of the 31 P resonance signal, whereas downfield shifts of thiophosphates were observed [88]. In α-aminoalkyl phosphonates and phosphinates, the nitrogen protonation gives rise to the 31 P peak downfield shift greater than the upfield shift upon the phosphonate oxygen protonation [54,89,90]. Thus, 31 P chemical shifts are amenable to respond to protonation effects of remote groups.…”

“…The impacts of protonation state and conformation on metal-binding characteristics for carboxylate and carbamoyl derivatives of cyclen and cyclam (12-and 14-membered tetraazamacrocycles) have been reviewed by Meyer et al [193]. 1 H NMR-pH titrations of cyclic polyamino polyphosphonates and polyphosphinates [87,90,194,195] revealed that the main factors determining their protonation sequence are the same as for polycarboxylates described above. The C j,P shielding constants proved to be pH-dependent, indicating conformational changes [87,194].…”

Chemical and biological evaluation of 153Sm and 166Ho complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylphosphonic acid monoethylester) (H4dotpOEt)

“…Its lanthanide(III) complexes are kinetically inert but the rate of their formation is rather slow [24,25]; the complexes have a high affinity for calcified tissues [10,18,19,[26][27][28][29][30][31]. On the other hand, tetrakis(methylphosphinic acid) H 4 dota analoges (Chart 1; R 0 = H, Et) form complexes with lower stability constants than those of the parent ligand as they exhibit a lower overall basicity [32][33][34][35]. It was shown that other properties of their complexes (rate of complex formation and decomposition, hydrophilicity, biodistribution, etc.)…”

Application of multivariate resolution methods to the study of biochemical and biophysical processes

“…Those are sometimes termed hard-modeling-based methods. Hence, for equilibrium studies, the postulated method consisted of the stoichiometries of the species involved and rough estimations of equilibrium constants [8][9][10][11]. An optimization process whereby the proposed equilibrium constants are iteratively reWned until a good Wt is found between the Wnal values and the experimental data is then started.…”