75953-69-4

Upstream product

• 31255-10-4 1,2-bis-(2-bromo-ethoxy)-ethane 
• 1576-37-0 N-benzyl-p-toluenesulfonamide 
• 929-59-9 3,6-dioxa-1,8-diaminooctane 
• 100-52-7 benzaldehyde 

Downstream Products

• 1126102-58-6 1,2-bis(N-benzyl-N-tert-butoxycarbonylmethyl-2-aminoethoxy)ethane 
• 66582-29-4 7,16-dibenzyl-2,3-dimethyl-7,16-diaza-1,4,10,13-tetraoxacyclopentadecane-6,17-dione 
• 75953-81-0 3,12-dibenzyl-3,12-diaza-6,9,17-trioxabicyclo<12,2,1>heptadeca-14,16-diene-2,13-dione 

Relevant academic research and scientific papers

1H and17O NMR relaxometric study in aqueous solution of Gd(III) complexes of EGTA-like derivatives bearing methylenephosphonic groups

The Gd(III) complexes of three new octadentate chelators, prepared by substitution of four, two, and one carboxylate groups of EGTA with phosphonate groups, have been investigated by 1H and 17O NMR relaxometric techniques in aqueous solutions. The analysis of the solvent proton relaxivity data as a function of pH, temperature, and magnetic field strength (nuclear magnetic relaxation dispersion (NMRD) profiles) in combination with the 17O transverse relaxation rate data at variable temperature allowed assessing the hydration state of the complexes, the occurrence of pH-dependent oligomerization processes for the tetraphosphonate derivative, the presence of a well-defined second sphere of hydration that markedly contributes to the relaxivity, and the values of the structural and dynamic relaxation parameters. In addition, in the case of themonophosphonate derivative the presence of a coordinated water molecule has allowed evaluation of the kinetic parameters of the exchange process, highly relevant for the possible use of this Gd(III) complex as anMRI probe. The rate of exchange of thewatermolecule, 298kex = 4.2 × 108s -1, is one of the highest measured so far for a nonacoordinate Gd(III) chelate and optimal for developing contrast-enhancing probes of high efficacy at high magnetic fields. Copyright

SYNTHESIS OF MACROCYCLIC POLYETHER-DIAMIDES AND THEIR MEMBRANE SELECTIVITY

The preparation of a series of polyether-diamides with different structure of the macrocyclic chain is described.The ion-selective properties of these compounds with respect to ions of the I and II group were investigated electrochemically in poly(vinyl chloride) membranes plasticised with 2-nitro-1-octyloxybenzene.The relationships between the structure of ionophores and their membrane selectivity are discussed.