2,3-Bis-<1-methyl-imidazolyl-(2)>-chinoxalin | 20062-58-2

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 二氮杂萘
• 英文名称: 2,3-Bis-<1-methyl-imidazolyl-(2)>-chinoxalin
• 英文别名: 2,3-bis(1-methylimidazol-2-yl)quinoxaline；2,3-bis-(1-methyl-1H-imidazol-2-yl)-quinoxaline；bmiq；2,3-Bis(1-methylimidazol-2-yl)quinoxaline
• CAS: 20062-58-2
• 化学式: C₁₆H₁₄N₆
• 分子量: 290.327
• InChiKey: LQBFGWFMWVWKGH-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.8
• 重原子数：
  22
• 可旋转键数：
  2
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.12
• 拓扑面积：
  61.4
• 氢给体数：
  0
• 氢受体数：
  4

反应信息

• 作为反应物：
  描述：

  2,3-Bis-<1-methyl-imidazolyl-(2)>-chinoxalin 以 四氢呋喃 、 二氯甲烷 为溶剂， 生成 Mo(CO)4(2,3-bis(1-methylimidazol-2-yl)quinoxaline(1-))(1-)
  参考文献：
  名称：

  Separation of Metal Binding and Electron Transfer Sites as a Strategy To Stabilize the Ligand-Reduced and Metal-Oxidized Form of [Mo(CO)₄L]

  摘要：

  The zerovalent metal in [Mo(CO)(4)(bmiq)] binds the two imidazole-N-imine donors of 2,3-bis(1-methylimidazol-2-yl)quinoxaline (bmiq), resulting in a seven-membered chelate ring coordinated in cis configuration. DFT calculations confirm the preference for a seven-membered vs five-membered ring chelation alternative as well as the experimental structural parameters. The complex is reversibly reduced in CH2Cl2 at -2.08 V and reversibly oxidized at -0.14 V vs ferrocenium/ferrrocene. The facilitated oxidation to a stable cation is attributed to the donor effect from the imidazole rings. In agreement with the DFT-calculated characteristics of the HOMO and LUMO, the in situ EPR studies at a Pt electrode reveal a Mo-I signature for the cation (g(1) = 1.967, g(2) = 1.944, g(3) = 1.906; A(iso)((95,97) MO) = 50 G) and a quinoxaline radical-type EPR spectrum with dominant N-14 coupling (2 N) of 6.0 G for the anion. IR spectroelectrochemistry confirms these assignments, showing small (Delta nu <= 20 cm(-1)) low-energy shifts of carbonyl stretching bands on reduction but significantly larger high-energy shifts (Delta nu = 77-142 cm(-1)) after oxidation. The neutral compound with a weak, broad MLCT absorption band at 500 nm is photolabile in solution. The unusual stability of both the anion and the cation is attributed to the spatial and electronic separation of the sites for electron loss (at the metal) and for electron uptake (at the uncoordinated quinoxaline ring).

  DOI：

  10.1021/om2007858

文献信息

• 2,3-Bis(1-methylimidazol-2-yl)quinoxaline (bmiq), a new ligand with decoupled electron transfer and metal coordination sites: the very different redox behaviour of isoelectronic complexes with [PtCl2] and [AuCl2]+
  作者：Ece Bulak、Tereza Varnali、Brigitte Schwederski、Biprajit Sarkar、Ingo Hartenbach、Jan Fiedler、Wolfgang Kaim

  DOI：10.1039/c0dt01282c

  日期：——

  The new, potentially ambidentate heterocyclic ligand 2,3-bis(1-methylimidazol-2-yl)quinoxaline (bmiq) was obtained from 2,3-bis(1-methylimidazol-2-yl)glyoxal and 1,2-diaminobenzene. Its coordination to PtCl2 and to the isoelectronic [AuCl2]+ in [AuCl2(bmiq)](AuCl4) occurs via the imine N donors of the imidazolyl groups, leading to the formation of seven-membered chelate rings with boat conformation

  新的潜在歧义的杂环配体 2,3-双（1-甲基咪唑-2-基）喹喔啉 （bmiq）由2,3-双（1-甲基咪唑-2-基）乙二醛和 1,2-二氨基苯。其与PtCl 2和[AuCl 2（bmiq）]（AuCl 4）中的等电性[AuCl 2 ] +的配位通过咪唑基的亚胺N供体发生，导致形成具有船形的七元螯合环。根据光谱电化学（UV-vis-NIR，EPR），与[PtCl 2（bmiq）]和游离配体可逆的电子加成发生在分子的（非配位）喹喔啉部分，与相关的类似。双嘧啶[3,2- a：2'，3'- c的络合物]吩嗪（dppz），2,3-双（2-吡啶基）喹喔啉（bpq）和2,3-双（二烷基膦基）喹喔啉（QuinoxP）。DFT计算证实了实验结果（结构，光谱学），并且还指出了喹喔啉N原子的配位潜力。根据实验和DFT结果，[AuCl 2（bmiq）] +中的电子加成不是在配体处发生，而是在金属处发生。
• Separation of Metal Binding and Electron Transfer Sites as a Strategy To Stabilize the Ligand-Reduced and Metal-Oxidized Form of [Mo(CO)₄L]
  作者：Ece Bulak、Tereza Varnali、Brigitte Schwederski、Denis Bubrin、Jan Fiedler、Wolfgang Kaim

  DOI：10.1021/om2007858

  日期：2011.12.12

  The zerovalent metal in [Mo(CO)(4)(bmiq)] binds the two imidazole-N-imine donors of 2,3-bis(1-methylimidazol-2-yl)quinoxaline (bmiq), resulting in a seven-membered chelate ring coordinated in cis configuration. DFT calculations confirm the preference for a seven-membered vs five-membered ring chelation alternative as well as the experimental structural parameters. The complex is reversibly reduced in CH2Cl2 at -2.08 V and reversibly oxidized at -0.14 V vs ferrocenium/ferrrocene. The facilitated oxidation to a stable cation is attributed to the donor effect from the imidazole rings. In agreement with the DFT-calculated characteristics of the HOMO and LUMO, the in situ EPR studies at a Pt electrode reveal a Mo-I signature for the cation (g(1) = 1.967, g(2) = 1.944, g(3) = 1.906; A(iso)((95,97) MO) = 50 G) and a quinoxaline radical-type EPR spectrum with dominant N-14 coupling (2 N) of 6.0 G for the anion. IR spectroelectrochemistry confirms these assignments, showing small (Delta nu <= 20 cm(-1)) low-energy shifts of carbonyl stretching bands on reduction but significantly larger high-energy shifts (Delta nu = 77-142 cm(-1)) after oxidation. The neutral compound with a weak, broad MLCT absorption band at 500 nm is photolabile in solution. The unusual stability of both the anion and the cation is attributed to the spatial and electronic separation of the sites for electron loss (at the metal) and for electron uptake (at the uncoordinated quinoxaline ring).