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Molecular weight determination of coordination and organometallic oligomers by T 1 and NOE constant measurements: concepts and challenges
Author(s) -
Harvey Pierre D.
Publication year - 2004
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200450505
Subject(s) - chemistry , group 2 organometallic chemistry , organometallic chemistry , polymer , relaxation (psychology) , crystallography , stability constants of complexes , lattice constant , molecule , crystal structure , organic chemistry , physics , optics , psychology , social psychology , aqueous solution , diffraction
This paper describes how to determine molecular weights of coordination and organometallic polymers (or rather oligomers) in solution using spin‐lattice relaxation time (T 1 ) and Nuclear Overhauser Enhancement constant (η NOE ) measurements. The methodology is explained using simple organometallic‐complexes such as M(CN‐t‐Bu) 4 + complexes (M = Cu, Ag). Very good results are obtained for oligomers that exhibit a rigid structure. Conversely, very poor results are extracted when the materials show flexible chains in the backbone. The typical examples for rigid and flexible oligomers are the {Ag(dmb) 2 + } n (dmb = 1,8‐diisocyano‐p‐menthane), and {Pd 2 (dmb) 2 (diphos) 2+ } n (diphos = dppa, dppb, dpppent, and dpph) as well as {Pd 2 (diphos) 2 (dmb) 2+ } n (diphos = dppe, dppr, and dppp R ; R = O(CH 2 ) 2 O‐naphthyl), respectively.