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• 作者：Chen Yang^a ; Ming Yang Tsai^a ; Sheng-Wei Hung^a ; Jyh-Horung Chen^a ; ^{JyhHChen@dragon.nchu.edu.tw} ; Shin-Shin Wang^b ; Jo-Yu Tung^c
• 关键词：X-ray diffraction ; Manganese(III) N-confused porphyrin ; Ferromagnetic interaction ; Antiferromagnetic interaction ; SQUID
• 刊名：Polyhedron
• 出版年：2012
• 期刊代码：87_02775387
• 类别：ch
• 出版时间：23 April, 2012
• 卷：37
• 期：1
• 页码：1-8
• 文件大小：917 K

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-NCH₂-p-C₆H₄-CO₂CH₃NCTPP); 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-NCH₂-p-C₆H₄-CO₂CH₃NCTPP)Br; 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-NCH₂-CHCH₂NCTPP)Br; 6] were determined. The coordination sphere around Ni(II) in 5 is described as four-coordinate square-planar, whereas for Mn(III) in 6 and 7, it is a five-coordinate square pyramid (SPY-5) in which the unidentate Br^{鈭?/sup> ligand occupies the axial site. The g_eff 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 6 (or 7). The magnitude of the axial (D) zero-field splitting (ZFS) for the mononuclear Mn(III) centre in 6 (or 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 6 (or 7) are arranged in a dimeric network. A weak Mn(III)路路路Mn(III) antiferromagnetic interaction (J_AF = 鈭?.02 cm鈭?) operates via a MnAA  鈥?#xA0;BrAA (p_z) 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 6. Moreover, a weak Mn(III)鈰疢n(III) ferromagnetic interaction (J_F = 0.58 cm鈭?) operates via a MnC  鈥?#xA0;BrC (p_z)  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 7.}