Magnetic properties in high-spin mononuclear manganese(III) inverted N-confused porphyrin complexes: Antiferromagnetic interaction of Mn(2-NCHb>2b>CHCHb>2b>NCTPP)Br versus ferromagnetic interaction of Mn(2-NCHb>2b>-p-Cb>6b>H
详细信息查看全文 | 推荐本文 |
摘要
The crystal structures of diamagnetic (2-aza-2-(4鈥?methyl methylbenzoate)-5,10,15,20-tetraphenyl-21-carbaporphyrinato-N,N鈥?N鈥? nickel(II) [Ni(2-NCHb>2b>-p-Cb>6b>Hb>4b>-COb>2b>CHb>3b>NCTPP); boldFont">5], paramagnetic bromo(2-aza-2-(4鈥?methyl methylbenzoate)-5,10,15,20-tetraphenyl-21-carbaporphyrinato-N,N鈥?N鈥? manganese(III) [Mn(2-NCHb>2b>-p-Cb>6b>Hb>4b>-COb>2b>CHb>3b>NCTPP)Br; boldFont">7], and paramagnetic bromo(2-aza-2-allyl-5,10,15,20-tetraphenyl-21-carbaporphyrinato-N,N鈥?N鈥?/em>) manganese(III) [Mn(2-NCHb>2b>-CHCHb>2b>NCTPP)Br; boldFont">6] were determined. The coordination sphere around Ni(II) in boldFont">5 is described as four-coordinate square-planar, whereas for Mn(III) in boldFont">6 and boldFont">7, it is a five-coordinate square pyramid (SPY-5) in which the unidentate Br鈭?/sup> ligand occupies the axial site. The gb>effb> value of 10.7 (or 11.1) measured from the parallel polarization of the X-band EPR spectra at 4 K is consistent with a high spin mononuclear manganese(III) centre (S = 2) in boldFont">6 (or boldFont">7). The magnitude of the axial (D) zero-field splitting (ZFS) for the mononuclear Mn(III) centre in boldFont">6 (or boldFont">7) was determined approximately as 鈭?.3 cm鈭? (or 鈭?.92 cm鈭?) by paramagnetic susceptibility measurements. Owing to the weak C(39A)-H(39B)鈰疊rBA [or C(45A)-H(45B)路路路BrC] intermolecular hydrogen bonds, the mononuclear Mn(III) neutral molecules of boldFont">6 (or boldFont">7) are arranged in a dimeric network. A weak Mn(III)路路路Mn(III) antiferromagnetic interaction (Jb>AFb> = 鈭?.02 cm鈭?) operates via a MnAA  鈥?#xA0;BrAA (pb>zb>) 鈥?#xA0;H(39D) (s) 鈥?#xA0;C(39B) 鈥?#xA0;N(4B) 鈥?#xA0;C(16B) 鈥?#xA0;C(17B) 鈥?#xA0;MnBA superexchange pathway in complex boldFont">6. Moreover, a weak Mn(III)鈰疢n(III) ferromagnetic interaction (Jb>Fb> = 0.58 cm鈭?) operates via a MnC  鈥?#xA0;BrC (pb>zb>)  H(45B) (s) 鈥?#xA0;C(45A) 鈥?#xA0;N(4A) 鈥?#xA0;C(18A) 鈥?#xA0;C(17A) 鈥?#xA0;MnA superexchange pathway in boldFont">7.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700