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A Novel pH‐Sensitive MRI Contrast Agent
Author(s) -
Zhang Shanrong,
Wu Kuangcong,
Sherry A. Dean
Publication year - 1999
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/(sici)1521-3773(19991102)38:21<3192::aid-anie3192>3.0.co;2-#
Subject(s) - phosphonate , protonation , gadolinium , chemistry , molecule , derivative (finance) , amide , coordination sphere , proton , contrast (vision) , stereochemistry , crystallography , computational chemistry , organic chemistry , ion , physics , quantum mechanics , artificial intelligence , computer science , financial economics , economics
Abstract A tetrasubstituted derivative of 1,4,7,10‐tetraazacyclododecane with amide coordinating groups and extended noncoordinating phosphonate groups forms a complex with gadolinium( III ) (shown in the picture) which contains one slowly exchanging inner‐sphere water molecule ( τ M =21 μs). The 20‐MHz water proton relaxivity of the complex was found to be highly pH dependent. Protonation of the noncoordinating phosphonate groups appears to catalyze prototropic exchange of the bound water protons, thereby providing a mechanism for enhanced water contrast below pH 7.