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A Domino Fusion of an Organic Ligand Depended on Metal-Induced and Oxygen Insertion,Unraveled by Crystallography,Mass Spectrometry,and DFT Calculations |
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| Authors: | Jin-Ming Chen Liang Peng Fu-Fang Zhou Dr Bin Liu Dr Cheng Hou Jia-Wei Li Zhou Huang Dr Mohamedally Kurmoo Prof Dr Ming-Hua Zeng |
| Institution: | 1. Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004 P.R. China
Hubei Collaborative Innovation Center for Advanced Chemical Materials, Ministry of Education Key Laboratory for the Synthesis, Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan, 430062 P.R. China These authors contributed equally to this work.;2. Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004 P.R. China These authors contributed equally to this work.;3. Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004 P.R. China;4. Hubei Collaborative Innovation Center for Advanced Chemical Materials, Ministry of Education Key Laboratory for the Synthesis, Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan, 430062 P.R. China;5. Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004 P.R. China College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004 P.R. China;6. Institut de Chimie de Strasbourg, CNRS-UMR7177, Université de Strasbourg, 4 rue Blaise Pascal, Strasbourg, 67070 France |
| Abstract: | Herein, the reaction of (1-methyl-1 H-benzod]imidazol-2-yl)methanamine ( L1 ) with Co(H2O)6Cl2, in CH3CN at 120 °C, leading to the 2,3,5,6-tetrakis(1-methyl-1 H-benzod]imidazol-2-yl)pyrazine ( 3 ), isolated as a dimeric cluster {CoII2( 3 )Cl4] ⋅ 2 CH3CN} ( 2 ), is reported. When O2 and H2O are present, (1-methyl-1 H-benzod]imidazole-2-carbonyl)amide (H L1′ ) is first formed and crystallized as CoIII( L1 )2( L1′ )]Cl2 ⋅ 2 H2O ( 4 ) before fusion of H L1′ with L1 , giving 1-methyl-N-(1-methyl-1 H-benzod]imidazol-2-carbonyl)-1 H-benzod]imidazol-2-carboxamide (H L2′′ ) forming a one-dimensional (1D) chain of CoII3( L2′′ )2Cl4]n ( 5 ). The combination of crystallography and mass spectrometry (ESI-MS) of isolated crystals and the solutions taken from the reaction as a function time reveal seven intermediate steps leading to 2 , but six steps for 5 , for which a different sequence takes place. Control and isotope labeling experiments confirm the two carbonyl oxygen atoms in 5 originate from both air and water. The dependence on the metals, compared with FeCl3 ⋅ 6 H2O leading to a stable triheteroarylmethyl radical, is quite astounding, which could be attributed to the different oxidation states of the metals and coordination modes confirmed by DFT calculations. This metal and valence dependent process is a very useful way for selectively obtaining these large molecules, which are unachievable by common organic synthesis. |
| Keywords: | cobalt-mediated reactions crystallography ESI-MS in situ reactions tetrasubstituted pyrazine |