Different ways of coordination for aminoalkyldiphosphonic acids in palladium(II) complexes
                                
                                    
                                        作者:A. N. Kozachkova、A. V. Dudko、N. V. Tsaryk、V. V. Trachevskii、A. B. Rozhenko、V. I. Pekhnyo                                    
                                    
                                        DOI:10.1134/s1070328411120025
                                    
                                    
                                        日期:2011.12
                                    
                                    Complexation in the systems K2PdCl4-3-amino-1-hydroxypropane-1,1-diyldiphosphonic acid (AHPDP) and K2PdCl4-1-aminoethane-1,1-diyldiphosphonic acid (AEDP) was studied using pH-potentiometry, spectrophotometry, and P-31 NMR spectroscopy. It was found that AHPDP in equimolar complexes is coordinated by Pd(II) in a bidentate fashion through two phosphonate O atoms forming a six-membered chelate [O,O]-ring, while AEDP is coordinated through the N atom and one phosphonate O atom forming a five-membered chelate [N,O]-ring. In 1: 2 complexes of Pd(II) with AEDP, the second AEDP molecule is coordinated by Pd(II) in a similar way to form a second five-membered [N,O]-ring. The latter complexes show cis-trans and syn-anti isomerism. The structural characteristics of the corresponding isomers were calculated at the DFT level of theory and their stabilities were compared.