Phosphorus-containing podands. 9. Synthesis of oligoethylene glycol bis(diphenylphosphinylethyl) esters and their complexing properties with respect to alkali metal cations in a low-polarity solvent

Modeling of Ion Complexation and Extraction Using Substructural Molecular Fragments

“…Complexation Data. Complexation data (stability constants) for podands, [46][47][48][49][50][51][52][53][54][55][56] crown ethers, 7 (Chart 1) and β-cyclodextrin 57 were critically selected from the THECO-MAC database, 3 which can export data into SDF format.…”

“…They possess a remarkable binding affinity for alkali cations, which varies as a function of the nature of constitutive fragments. A set of 84 stability constants (log β) for the 1:1 complexes of podands and with K + in the mixed solvent THF:CHCl 3 (4:1 volume) at 298 K [46][47][48][49][50][51][52][53][54][55][56] has been selected from the THECOMAC database. 3,7 The learning set excluding rare fragments, contained 70 or 71 podands depending on the decomposition scheme, while the validation set contained 5 podands.…”

“…Both decomposition schemes give a reasonable standard deviation s ) 0.42 (log β units), which is similar to typical experimental errors. [46][47][48][49][50][51][52][53][54][55][56] The second group of models (6-9) mostly involves the calculations within nonlinear fitting equations, eqs 2 and 3, which include larger number of variables compared to the models from the first group. According to statistical criteria, 40 nevertheless, the quality of the calculations for the models from the first and second groups is similar.…”

“…Standard deviations for these correlations (0.34 and 0.28 for I(AB, 2-3) and I(AB, 2-4), respectively) are within experimental error (0.3-0.4). [46][47][48][49][50][51][52][53][54][55][56] 3.2.2. Complexation of Crown Ethers with the Sodium Cation.…”

Complexation of phosphoryl-containing mono-, bi- and tri-podands with alkali cations in acetonitrile. Structure of the complexes and binding selectivity

“…10 Podands can be easily modified by varying substituents at phosphorus, in particular, the 'bridges' between ether oxygens and P᎐ ᎐ O groups. More than 50 phosphoryl-containing mono-podands and their complexes with alkali, alkaline-earth and rare-earth cations have been synthesized [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] and studied by conductometry, 30,31 calorimetry, 32-34 extraction 35 and IR spectroscopy [36][37][38] methods. Compared to macrocyclic ionophores (crown ethers, cryptands), mono-podands are not preorganized.…”