Structural, Spectroscopic, Electrochemical, and Magnetic Properties for Manganese(II) Triazamacrocyclic Complexes.
Structural, Spectroscopic, Electrochemical, and Magnetic Properties for Manganese(II) Triazamacrocyclic Complexes.
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DOI：
10.1016/j.ica.2018.11.013
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发表时间：
2019-02-24
影响因子：
2.8
通讯作者：
Chavez FA
中科院分区：
文献类型：
--
作者：
Banerjee A;Tolla AS;Stjepanovic S;Sevilla MD;Goodsell JL;Angerhofer A;Brennessel WW;Loloee R;Chavez FA
本文报道了[Mn(tacn)2](OTf)2 (1) （tacd = 1,4,8-三氮杂环癸烷）、[Mn(tacd)2](OTf)2 (2) （tacd = 1,4,7-三氮杂环癸烷）和[Mn(tacn)2](OTf)2 (3) （tacn = 1,4,7-三氮杂环壬烷）的合成。对MnIII/II氧化还原对的电化学测量表明，配合物1具有最大的阳极电位（E1/2 = 1.16 V vs NHE， ΔEp = 106 mV），而配合物2 （E1/2 = 0.95 V， ΔEp = 108 mV）和3 （E1/2 = 0.93 V， ΔEp = 96 mV）。这是因为1具有最少的5元螯合环，因此稳定性最低。对1−3的磁性研究表明，所有配合物在研究的温度范围内（2 - 300 K）都保持高自旋。在甲醇玻璃中的x波段EPR研究表明，与1相比，2和3的锰（II）中心位于更扭曲的八面体几何构型中。为了简化光谱解释和提取ZFS参数，我们在频率高于200 GHz和场为7.5 t的情况下进行了高频高场EPR (HFEPR)，光谱数据的模拟结果为g = 2.0013和D = - 0.031 cm−1,g = 2.0008, D = - 0.0824 cm−1,|E/D| = 0.12, 2, g = 2.00028, D = - 0.0884 cm−1。这些结果与具有最扭曲几何的3一致。在1−3进行计算（PBE0/6-31G (d)）。结果表明，相较于2 （6.12 eV）和3 (6.26 eV)， 1具有最大的HOMO-LUMO隙能（6.37 eV）。配合物1的HOMO能量也最低，表明其稳定性较高。
We report the synthesis of [Mn(tacud)2](OTf)2 (1) (tacud = 1,4,8-triazacycloundecane), [Mn(tacd)2](OTf)2 (2) (tacd = 1,4,7-triazacyclodecane), and [Mn(tacn)2](OTf)2 (3) (tacn = 1,4,7-triazacyclononane). Electrochemical measurements on the MnIII/II redox couple show that complex 1 has the largest anodic potential of the set (E1/2 = 1.16 V vs NHE, ΔEp = 106 mV) compared to 2 (E1/2 = 0.95 V, ΔEp = 108 mV) and 3 (E1/2 = 0.93 V, ΔEp = 96 mV). This is due to the fact that 1 has the fewest 5-membered chelate rings and thus is least stabilized. Magnetic studies of 1−3 revealed that all complexes remain high spin throughout the temperature range investigated (2 – 300 K). X-band EPR investigations in methanol glass indicated that the manganese(II) centers for 2 and 3 resided in a more distorted octahedral geometric configuration compared to 1. To ease spectral interpretation and extract ZFS parameters, we performed high-frequency high-field EPR (HFEPR) at frequencies above 200 GHz and a field of 7.5 T. Simulation of the spectral data yielded g = 2.0013 and D = −0.031 cm−1 for 1, g = 2.0008, D = −0.0824 cm−1, |E/D| = 0.12 for 2, and g = 2.00028, D = −0.0884 cm−1 for 3. These results are consistent with 3 possessing the most distorted geometry. Calculations (PBE0/6–31G(d)) were performed on 1−3. Results show that 1 has the largest HOMO-LUMO gap energy (6.37 eV) compared to 2 (6.12 eV) and 3 (6.26 eV). Complex 1 also has the lowest HOMO energies indicating higher stability.
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影响因子：
4.3
作者：
Duboc, Carole;Collomb, Marie-Noelle;Neese, Frank
通讯作者：
Neese, Frank
影响因子：
6.1
作者：
Altomare, A;Burla, MC;Spagna, R
通讯作者：
Spagna, R
DOI：
10.1039/c39910000402
发表时间：
1991-03-15
影响因子：
--
作者：
BELAL, AA;FALLIS, I;PEACOCK, RD
通讯作者：
PEACOCK, RD
影响因子：
4
作者：
Bodsgard, Brett R.;Clark, Robert W.;Burstyn, Judith N.
通讯作者：
Burstyn, Judith N.
影响因子：
15
作者：
Carmieli, R;Manikandan, P;Goldfarb, D
通讯作者：
Goldfarb, D