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Magnetic Exchange Interaction in [BNITPhOPr] and [Cu(Cl 2 CHCO 2 ) 2 (NITpPy) 2 (H 2 O)]: A Density Functional Theory Study
Author(s) -
Ren Jie,
Wei HaiYan,
Wang Fan,
Chen ZhiDa,
Zhao QiHua
Publication year - 2003
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200300094
Subject(s) - chemistry , nitroxide mediated radical polymerization , delocalized electron , antiferromagnetism , crystallography , density functional theory , intramolecular force , radical , stereochemistry , computational chemistry , condensed matter physics , polymer , physics , radical polymerization , organic chemistry , copolymer
The magnetic exchange interaction and electronic structures for the nitronyl nitroxide free radical ( 1 ), (4,4,5,5‐tetramethyl‐4,5‐dihydro‐1 H ‐imidazolyl‐1‐oxyl 3‐oxide), nitronyl nitroxide biradical, [BNITPhOPr] ( 2 ), (1,3‐[di‐2‐(4,4,5,5‐tetramethyl‐4,5‐dihydro‐1 H ‐imidazolyl‐1‐oxyl 3‐oxide)phenoxy]propane) and Cu II ‐nitronyl nitroxide radical complex, [Cu(Cl 2 CHCO 2 ) 2 (NITpPy) 2 (H 2 O)] ( 3 ), (NITpPy=2‐(4‐pyridyl)‐4,4,5,5‐tetramethyl‐2‐imidazoline‐1‐oxy 3‐oxide) were studied by the broken symmetry (BS) approach within the density functional theory (DFT), combined with the spin‐Hamiltonian full‐matrix diagonalization method. The theoretically calculated magnetic coupling constant J values (‐0.10 ( 2 ), −12.9 ( 3 )) are approximately consistent with experimental results (‐0.24 ( 2 ) and‐11.5 ( 3 )). For the complex 3 , the magnetic coupling constant j (‐0.85) between two terminal radical ligands is also obtained, which has not been characterized experimentally. In contrast to radical 1 , the nitronyl nitroxide radicals in the biradical 2 and complex 3 behave as a more localized spin‐center. However, Cu II ion of the complex 3 exhibits a local‐spin delocalization to the surrounding atoms. Spin population analyses suggest that the intramolecular antiferromagnetic coupling for the biradical 2 is governed by the weak spin polarization through the bridging ligand and that the antiferromagnetic coupling interaction between the Cu II ion and nitronyl nitroxide radicals in the complex 3 is dominated by both the local‐spin delocalization on the Cu II ion and the global spin polarization mechanism.