Reduced N-Alkyl Substituted Bis(imino)pyridine Cobalt Complexes: Molecular and Electronic Structures for Compounds Varying by Three Oxidation States

View Author Information
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853
Max-Planck Institute for Bioinorganic Chemistry, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
*To whom correspondence should be addressed. E-mail: [email protected] (P.J.C.).
Cite this: Inorg. Chem. 2010, 49, 13, 6110–6123
Publication Date (Web):June 11, 2010
https://doi.org/10.1021/ic100717w
Copyright © 2010 American Chemical Society
Article Views
3387
Altmetric
-
Citations
LEARN ABOUT THESE METRICS
Read OnlinePDF (4 MB)
Supporting Info (1)»

Abstract

The stepwise 1−3 electron reduction of the N-alkyl substituted bis(imino)pyridine cobalt dichloride complexes, (RAPDI)CoCl2, was studied where RAPDI = 2,6-(RN═CMe)2C5H3N, R = C6H11 (Cy), CHMe2 (iPr). One electron reduction with either zinc metal or NaBEt3H furnished the bis(imino)pyridine cobalt monochloride compounds, (RAPDI)CoCl. X-ray diffraction on the (iPrAPDI)CoCl derivative established a distortion from square planar geometry where the chloride ligand is lifted out of the idealized cobalt-chelate plane. Superconducting Quantum Interference Device (SQUID) magnetometry on both compounds established spin crossover behavior with an S = 1 state being predominant at room temperature. Computational studies, in combination with experimental results, establish that the triplet spin isomer arises from a high spin Co(II) center (SCo = 3/2) antiferromagnetically coupled to a bis(imino)pyridine chelate radical anion, [PDI] (SPDI = 1/2). At lower temperatures, the Co(II) ion undergoes a spin transition to the low spin form (SCo = 1/2) and antiferromagnetic coupling gives rise to the observed diamagnetic ground state. Replacing the chloride ligand with a methyl group, namely (RAPDI)CoCH3, also yielded distorted compounds, albeit less pronounced, that are diamagnetic at room temperature. Two electron reduction of the (RAPDI)CoCl2 derivatives with excess 0.5% sodium amalgam or 2 equiv of NaBEt3H furnished the bis(chelate)cobalt complexes, (RAPDI)2Co, while three electron reduction with 3 equiv of sodium naphthalenide yielded the cobalt dinitrogen anions, [Na(solv)3][(RAPDI)CoN2] (solv = THF, Et2O). Both bis(chelate) compounds were crystallographically characterized and determined to have S = 3/2 ground states by SQUID magnetometry and electron paramagnetic resonance (EPR) spectroscopy. Computational studies, in combination with metrical parameters determined from X-ray diffraction, establish a high spin (SCo = 3/2) cobalt(II) center with two bis(imino)pyridine chelate radical anions. Antiferromagnetic coupling between the two chelate centered radicals is mediated by a doubly occupied t2g cobalt orbital and gives rise to the observed overall quartet ground state.

Supporting Information

ARTICLE SECTIONS
Jump To

Crystallographic details for (iPrAPDI)CoCl, (iPrAPDI)CoCMe, (iPrAPDI)2Co, and (CyAPDI)2Co in cif format. This material is available free of charge via the Internet at http://pubs.acs.org.

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Cited By


This article is cited by 87 publications.

  1. Marius Peters, Dirk Baabe, Miyuki Maekawa, Dirk Bockfeld, Marc-Kevin Zaretzke, Matthias Tamm, Marc D. Walter. Pogo-Stick Iron and Cobalt Complexes: Synthesis, Structures, and Magnetic Properties. Inorganic Chemistry 2019, 58 (24) , 16475-16486. https://doi.org/10.1021/acs.inorgchem.9b02411
  2. Rebeca Arevalo, Paul J. Chirik. Enabling Two-Electron Pathways with Iron and Cobalt: From Ligand Design to Catalytic Applications. Journal of the American Chemical Society 2019, 141 (23) , 9106-9123. https://doi.org/10.1021/jacs.9b03337
  3. Lukas Alig, Maximilian Fritz, Sven Schneider. First-Row Transition Metal (De)Hydrogenation Catalysis Based On Functional Pincer Ligands. Chemical Reviews 2019, 119 (4) , 2681-2751. https://doi.org/10.1021/acs.chemrev.8b00555
  4. Mei Wang, Christina Römelt, Thomas Weyhermüller, Karl Wieghardt. Coordination Modes, Oxidation, and Protonation Levels of 2,6-Pyridinediimine and 2,2′:6′,2′́-Terpyridine Ligands in New Complexes of Cobalt, Zirconium, and Ruthenium. An Experimental and Density Functional Theory Computational Study. Inorganic Chemistry 2019, 58 (1) , 121-132. https://doi.org/10.1021/acs.inorgchem.8b01949
  5. Kent G. Lopez, Thomas R. Cundari, and J. Brannon Gary . Cooperative Metal + Ligand Oxidative Addition and σ-Bond Metathesis: A DFT Study. Organometallics 2018, 37 (3) , 309-313. https://doi.org/10.1021/acs.organomet.7b00715
  6. Pengfei Ji, Yang Song, Tasha Drake, Samuel S. Veroneau, Zekai Lin, Xiandao Pan, and Wenbin Lin . Titanium(III)-Oxo Clusters in a Metal–Organic Framework Support Single-Site Co(II)-Hydride Catalysts for Arene Hydrogenation. Journal of the American Chemical Society 2018, 140 (1) , 433-440. https://doi.org/10.1021/jacs.7b11241
  7. Michael E. Noss, Anne T. Hylden, Patrick J. Carroll, and Donald H. Berry . Electrochemistry of Ruthenium Bis(imino)pyridine Compounds: Evidence for an ECE Mechanism and Isolation of Mono and Dicationic Complexes. Inorganic Chemistry 2018, 57 (1) , 435-445. https://doi.org/10.1021/acs.inorgchem.7b02677
  8. Grant W. Margulieux, Máté J. Bezdek, Zoë R. Turner, and Paul J. Chirik . Ammonia Activation, H2 Evolution and Nitride Formation from a Molybdenum Complex with a Chemically and Redox Noninnocent Ligand. Journal of the American Chemical Society 2017, 139 (17) , 6110-6113. https://doi.org/10.1021/jacs.7b03070
  9. Garvin M. Peters, Jacob B. Winegrad, Michael R. Gau, Gregory H. Imler, Beibei Xu, Shenqiang Ren, Bradford B. Wayland, and Michael J. Zdilla . Synthesis and Structure of 2,5-Bis[N-(2,6-mesityl)iminomethyl]pyrrolylcobalt(II): Evidence for One-Electron-Oxidized, Redox Noninnocent Ligand Behavior. Inorganic Chemistry 2017, 56 (6) , 3377-3385. https://doi.org/10.1021/acs.inorgchem.6b02898
  10. Nadia G. Léonard, Máté J. Bezdek, and Paul J. Chirik . Cobalt-Catalyzed C(sp2)–H Borylation with an Air-Stable, Readily Prepared Terpyridine Cobalt(II) Bis(acetate) Precatalyst. Organometallics 2017, 36 (1) , 142-150. https://doi.org/10.1021/acs.organomet.6b00630
  11. Wan-Yi Chu, Ryan Gilbert-Wilson, and Thomas B. Rauchfuss , Maurice van Gastel and Frank Neese . Cobalt Phosphino-α-Iminopyridine-Catalyzed Hydrofunctionalization of Alkenes: Catalyst Development and Mechanistic Analysis. Organometallics 2016, 35 (17) , 2900-2914. https://doi.org/10.1021/acs.organomet.6b00457
  12. Max R. Friedfeld, Michael Shevlin, Grant W. Margulieux, Louis-Charles Campeau, and Paul J. Chirik . Cobalt-Catalyzed Enantioselective Hydrogenation of Minimally Functionalized Alkenes: Isotopic Labeling Provides Insight into the Origin of Stereoselectivity and Alkene Insertion Preferences. Journal of the American Chemical Society 2016, 138 (10) , 3314-3324. https://doi.org/10.1021/jacs.5b10148
  13. Lei Zhang and Zheng Huang . Synthesis of 1,1,1-Tris(boronates) from Vinylarenes by Co-Catalyzed Dehydrogenative Borylations–Hydroboration. Journal of the American Chemical Society 2015, 137 (50) , 15600-15603. https://doi.org/10.1021/jacs.5b11366
  14. Jason England, Eckhard Bill, Thomas Weyhermüller, Frank Neese, Mihail Atanasov, and Karl Wieghardt . Molecular and Electronic Structures of Homoleptic Six-Coordinate Cobalt(I) Complexes of 2,2′:6′,2″-Terpyridine, 2,2′-Bipyridine, and 1,10-Phenanthroline. An Experimental and Computational Study. Inorganic Chemistry 2015, 54 (24) , 12002-12018. https://doi.org/10.1021/acs.inorgchem.5b02415
  15. Valerie A. Schmidt, Jordan M. Hoyt, Grant W. Margulieux, and Paul J. Chirik . Cobalt-Catalyzed [2π + 2π] Cycloadditions of Alkenes: Scope, Mechanism, and Elucidation of Electronic Structure of Catalytic Intermediates. Journal of the American Chemical Society 2015, 137 (24) , 7903-7914. https://doi.org/10.1021/jacs.5b04034
  16. Paul J. Chirik . Iron- and Cobalt-Catalyzed Alkene Hydrogenation: Catalysis with Both Redox-Active and Strong Field Ligands. Accounts of Chemical Research 2015, 48 (6) , 1687-1695. https://doi.org/10.1021/acs.accounts.5b00134
  17. Jennifer V. Obligacion, Jamie M. Neely, Aliza N. Yazdani, Iraklis Pappas, and Paul J. Chirik . Cobalt Catalyzed Z-Selective Hydroboration of Terminal Alkynes and Elucidation of the Origin of Selectivity. Journal of the American Chemical Society 2015, 137 (18) , 5855-5858. https://doi.org/10.1021/jacs.5b00936
  18. Suraj Mondal, Shuvankar Mandal, Luca Carrella, Arpita Jana, Michel Fleck, Andreas Köhn, Eva Rentschler, and Sasankasekhar Mohanta . A Series of MIICuII3 Stars (M = Mn, Ni, Cu, Zn) Exhibiting Unusual Magnetic Properties. Inorganic Chemistry 2015, 54 (1) , 117-131. https://doi.org/10.1021/ic501900d
  19. Jonathan M. Darmon, Renyuan Pony Yu, Scott P. Semproni, Zoë R. Turner, S. Chantal E. Stieber, Serena DeBeer, and Paul J. Chirik . Electronic Structure Determination of Pyridine N-Heterocyclic Carbene Iron Dinitrogen Complexes and Neutral Ligand Derivatives. Organometallics 2014, 33 (19) , 5423-5433. https://doi.org/10.1021/om500727t
  20. Jeewantha S. Hewage, Sarath Wanniarachchi, Tyler J. Morin, Brendan J. Liddle, Megan Banaszynski, Sergey V. Lindeman, Brian Bennett, and James R. Gardinier . Homoleptic Nickel(II) Complexes of Redox-Tunable Pincer-type Ligands. Inorganic Chemistry 2014, 53 (19) , 10070-10084. https://doi.org/10.1021/ic500657e
  21. Leila G. Ranis, Kalpani Werellapatha, Nicholas J. Pietrini, Bruce A. Bunker, and Seth N. Brown . Metal and Ligand Effects on Bonding in Group 6 Complexes of Redox-Active Amidodiphenoxides. Inorganic Chemistry 2014, 53 (19) , 10203-10216. https://doi.org/10.1021/ic501222n
  22. Wesley D. Morris, Peter T. Wolczanski, Jörg Sutter, Karsten Meyer, Thomas R. Cundari, and Emil B. Lobkovsky . Iron and Chromium Complexes Containing Tridentate Chelates Based on Nacnac and Imino- and Methyl-Pyridine Components: Triggering C—X Bond Formation. Inorganic Chemistry 2014, 53 (14) , 7467-7484. https://doi.org/10.1021/ic500807y
  23. David C. Lacy, Charles C. L. McCrory, and Jonas C. Peters . Studies of Cobalt-Mediated Electrocatalytic CO2 Reduction Using a Redox-Active Ligand. Inorganic Chemistry 2014, 53 (10) , 4980-4988. https://doi.org/10.1021/ic403122j
  24. Ian A. Gass, Subrata Tewary, Gopalan Rajaraman, Mousa Asadi, David W. Lupton, Boujemaa Moubaraki, Guillaume Chastanet, Jean-Francois Létard, and Keith S. Murray . Solvate-Dependent Spin Crossover and Exchange in Cobalt(II) Oxazolidine Nitroxide Chelates. Inorganic Chemistry 2014, 53 (10) , 5055-5066. https://doi.org/10.1021/ic5001057
  25. Valerie A. Williams, Peter T. Wolczanski, Jörg Sutter, Karsten Meyer, Emil B. Lobkovsky, and Thomas R. Cundari . Iron Complexes Derived from {nacnac-(CH2py)2}− and {nacnac-(CH2py)(CHpy)}n Ligands: Stabilization of Iron(II) via Redox Noninnocence. Inorganic Chemistry 2014, 53 (9) , 4459-4474. https://doi.org/10.1021/ic5001123
  26. Pradip Ghosh, Subhas Samanta, Suman K. Roy, Serhiy Demeshko, Franc Meyer, and Sreebrata Goswami . Introducing a New Azoaromatic Pincer Ligand. Isolation and Characterization of Redox Events in Its Ferrous Complexes. Inorganic Chemistry 2014, 53 (9) , 4678-4686. https://doi.org/10.1021/ic500355f
  27. Jennifer V. Obligacion, Scott P. Semproni, and Paul J. Chirik . Cobalt-Catalyzed C–H Borylation. Journal of the American Chemical Society 2014, 136 (11) , 4133-4136. https://doi.org/10.1021/ja500712z
  28. Xiao-Juan Yang, Xiaohui Fan, Yanxia Zhao, Xuting Wang, Bin Liu, Ji-Hu Su, Qingsong Dong, Maolin Xu, and Biao Wu . Synthesis and Characterization of Cobalt Complexes with Radical Anionic α-Diimine Ligands. Organometallics 2013, 32 (23) , 6945-6949. https://doi.org/10.1021/om4003686
  29. Kathrin H. Hopmann . Cobalt–Bis(imino)pyridine-Catalyzed Asymmetric Hydrogenation: Electronic Structure, Mechanism, and Stereoselectivity. Organometallics 2013, 32 (21) , 6388-6399. https://doi.org/10.1021/om400755k
  30. Renyuan Pony Yu, Jonathan M. Darmon, Carsten Milsmann, Grant W. Margulieux, S. Chantal E. Stieber, Serena DeBeer, and Paul J. Chirik . Catalytic Hydrogenation Activity and Electronic Structure Determination of Bis(arylimidazol-2-ylidene)pyridine Cobalt Alkyl and Hydride Complexes. Journal of the American Chemical Society 2013, 135 (35) , 13168-13184. https://doi.org/10.1021/ja406608u
  31. Jordan M. Hoyt, Kevin T. Sylvester, Scott P. Semproni, and Paul J. Chirik . Synthesis and Electronic Structure of Bis(imino)pyridine Iron Metallacyclic Intermediates in Iron-Catalyzed Cyclization Reactions. Journal of the American Chemical Society 2013, 135 (12) , 4862-4877. https://doi.org/10.1021/ja400895j
  32. Jacob A. Przyojski, Hadi D. Arman, and Zachary J. Tonzetich . NHC Complexes of Cobalt(II) Relevant to Catalytic C–C Coupling Reactions. Organometallics 2013, 32 (3) , 723-732. https://doi.org/10.1021/om3010756
  33. Thomas R. Dugan, Eckhard Bill, K. Cory MacLeod, Gemma J. Christian, Ryan E. Cowley, William W. Brennessel, Shengfa Ye, Frank Neese, and Patrick L. Holland . Reversible C–C Bond Formation between Redox-Active Pyridine Ligands in Iron Complexes. Journal of the American Chemical Society 2012, 134 (50) , 20352-20364. https://doi.org/10.1021/ja305679m
  34. Joshua H. Palmer and Kyle M. Lancaster . Molecular Redox: Revisiting the Electronic Structures of the Group 9 Metallocorroles. Inorganic Chemistry 2012, 51 (22) , 12473-12482. https://doi.org/10.1021/ic3018826
  35. Zhenbo Mo, Dake Chen, Xuebin Leng, and Liang Deng . Intramolecular C(sp3)–H Bond Activation Reactions of Low-Valent Cobalt Complexes with Coordination Unsaturation. Organometallics 2012, 31 (20) , 7040-7043. https://doi.org/10.1021/om300804a
  36. Jonathan M. Darmon, S. Chantal E. Stieber, Kevin T. Sylvester, Ignacio Fernández, Emil Lobkovsky, Scott P. Semproni, Eckhard Bill, Karl Wieghardt, Serena DeBeer, and Paul J. Chirik . Oxidative Addition of Carbon–Carbon Bonds with a Redox-Active Bis(imino)pyridine Iron Complex. Journal of the American Chemical Society 2012, 134 (41) , 17125-17137. https://doi.org/10.1021/ja306526d
  37. Averi Guha, Tanmay Chattopadhyay, Nanda Dulal Paul, Madhuparna Mukherjee, Somen Goswami, Tapan Kumar Mondal, Ennio Zangrando, and Debasis Das . Radical Pathway in Catecholase Activity with Zinc-Based Model Complexes of Compartmental Ligands. Inorganic Chemistry 2012, 51 (16) , 8750-8759. https://doi.org/10.1021/ic300400v
  38. Jonathan M. Darmon, Zoë R. Turner, Emil Lobkovsky, and Paul J. Chirik . Electronic Effects in 4-Substituted Bis(imino)pyridines and the Corresponding Reduced Iron Compounds. Organometallics 2012, 31 (6) , 2275-2285. https://doi.org/10.1021/om201212m
  39. Amarnath Bheemaraju, Richard L. Lord, Peter Müller, and Stanislav Groysman . Difference in the Reactivities of H- and Me-Substituted Dinucleating Bis(iminopyridine) Ligands with Nickel(0). Organometallics 2012, 31 (6) , 2120-2123. https://doi.org/10.1021/om300067z
  40. S. Chantal E. Stieber, Carsten Milsmann, Jordan M. Hoyt, Zoë R. Turner, Kenneth D. Finkelstein, Karl Wieghardt, Serena DeBeer, and Paul J. Chirik . Bis(imino)pyridine Iron Dinitrogen Compounds Revisited: Differences in Electronic Structure Between Four- and Five-Coordinate Derivatives.. Inorganic Chemistry 2012, 51 (6) , 3770-3785. https://doi.org/10.1021/ic202750n
  41. Sebastien Monfette, Zoë R. Turner, Scott P. Semproni, and Paul J. Chirik . Enantiopure C1-Symmetric Bis(imino)pyridine Cobalt Complexes for Asymmetric Alkene Hydrogenation. Journal of the American Chemical Society 2012, 134 (10) , 4561-4564. https://doi.org/10.1021/ja300503k
  42. Seth N. Brown . Metrical Oxidation States of 2-Amidophenoxide and Catecholate Ligands: Structural Signatures of Metal–Ligand π Bonding in Potentially Noninnocent Ligands. Inorganic Chemistry 2012, 51 (3) , 1251-1260. https://doi.org/10.1021/ic202764j
  43. Brenda A. Frazier, Erika R. Bartholomew, Peter T. Wolczanski, Serena DeBeer, Mitk’El Santiago-Berrios, Hector D. Abruña, Emil B. Lobkovsky, Suzanne C. Bart, Susanne Mossin, Karsten Meyer, and Thomas R. Cundari . Synthesis and Characterization of (smif)2Mn (n = 0, M = V, Cr, Mn, Fe, Co, Ni, Ru; n = +1, M = Cr, Mn, Co, Rh, Ir; smif =1,3-di-(2-pyridyl)-2-azaallyl). Inorganic Chemistry 2011, 50 (24) , 12414-12436. https://doi.org/10.1021/ic200376f
  44. Bryan D. Stubbert, Jonas C. Peters, and Harry B. Gray . Rapid Water Reduction to H2 Catalyzed by a Cobalt Bis(iminopyridine) Complex. Journal of the American Chemical Society 2011, 133 (45) , 18070-18073. https://doi.org/10.1021/ja2078015
  45. Ting Zhu, Truman C. Wambach, and Michael D. Fryzuk . New Cyclopentenyl-Linked [NPN] Ligands and Their Coordination Chemistry with Zirconium: Synthesis of a Dinuclear Side-On-Bound Dinitrogen Complex. Inorganic Chemistry 2011, 50 (21) , 11212-11221. https://doi.org/10.1021/ic201762r
  46. Di Zhu, Indira Thapa, Ilia Korobkov, Sandro Gambarotta, and Peter H. M. Budzelaar . Redox-Active Ligands and Organic Radical Chemistry. Inorganic Chemistry 2011, 50 (20) , 9879-9887. https://doi.org/10.1021/ic2002145
  47. Aaron M. Tondreau, Carsten Milsmann, Emil Lobkovsky, and Paul J. Chirik . Oxidation and Reduction of Bis(imino)pyridine Iron Dicarbonyl Complexes. Inorganic Chemistry 2011, 50 (20) , 9888-9895. https://doi.org/10.1021/ic200730k
  48. Tianpengfei Xiao, Peng Hao, Gerald Kehr, Xiang Hao, Gerhard Erker, and Wen-Hua Sun . Dichlorocobalt(II) Complexes Ligated by Bidentate 8-(Benzoimidazol-2-yl)quinolines: Synthesis, Characterization, and Catalytic Behavior toward Ethylene. Organometallics 2011, 30 (18) , 4847-4853. https://doi.org/10.1021/om2003392
  49. Tianpengfei Xiao, Shu Zhang, Gerald Kehr, Xiang Hao, Gerhard Erker, and Wen-Hua Sun . Bidentate Iron(II) Dichloride Complexes Bearing Substituted 8-(Benzimidazol-2-yl)quinolines: Synthesis, Characterization, and Ethylene Polymerization Behavior. Organometallics 2011, 30 (13) , 3658-3665. https://doi.org/10.1021/om200338b
  50. Sarah K. Russell, Carsten Milsmann, Emil Lobkovsky, Thomas Weyhermüller, and Paul J. Chirik . Synthesis, Electronic Structure, and Catalytic Activity of Reduced Bis(aldimino)pyridine Iron Compounds: Experimental Evidence for Ligand Participation. Inorganic Chemistry 2011, 50 (7) , 3159-3169. https://doi.org/10.1021/ic102186q
  51. Ian A. Gass, Christopher J. Gartshore, David W. Lupton, Boujemaa Moubaraki, Ayman Nafady, Alan M. Bond, John F. Boas, John D. Cashion, Carsten Milsmann, Karl Wieghardt, and Keith S. Murray . Anion Dependent Redox Changes in Iron Bis-terdentate Nitroxide {NNO} Chelates. Inorganic Chemistry 2011, 50 (7) , 3052-3064. https://doi.org/10.1021/ic102588h
  52. Connor Fleming, Dorothy Chung, Servando Ponce, David J. R. Brook, Jeffrey DaRos, Raja Das, Andrew Ozarowski, Sebastian A. Stoian. Valence tautomerism in a cobalt-verdazyl coordination compound. Chemical Communications 2020, 56 (32) , 4400-4403. https://doi.org/10.1039/D0CC01770A
  53. Marta Martín, Eduardo Sola. Recent advances in the chemistry of group 9—Pincer organometallics. 2020,,, 79-193. https://doi.org/10.1016/bs.adomc.2019.09.002
  54. Jarl Ivar van der Vlugt. Redox-Active Pincer Ligands. 2020,,, 135-179. https://doi.org/10.1007/3418_2020_68
  55. Immihan Sezen Aydogdu, Ilkay Gumus, Hakan Arslan. Hirshfeld surface and theoretical studies of 2,2,2-trichloro-N,N-bis(2-(2,2,2-trichloroacetamido)phenyl)acetamide compound. European Journal of Chemistry 2019, 10 (4) , 323-335. https://doi.org/10.5155/eurjchem.10.4.323-335.1920
  56. Aysegul Suzan Polat, Ilkay Gumus, Hakan Arslan. Vibrational spectroscopic and Hirshfeld surface analysis of N,N'-(azanediylbis(2,1-phenylene))bis(2-chloropropanamide). European Journal of Chemistry 2019, 10 (4) , 386-402. https://doi.org/10.5155/eurjchem.10.4.386-402.1921
  57. Mrinal Bhunia, Sumeet Ranjan Sahoo, Bikash Kumar Shaw, Shefali Vaidya, Anand Pariyar, Gonela Vijaykumar, Debashis Adhikari, Swadhin K. Mandal. Storing redox equivalent in the phenalenyl backbone towards catalytic multi-electron reduction. Chemical Science 2019, 10 (31) , 7433-7441. https://doi.org/10.1039/C9SC02057H
  58. Jia‐Wei Wang, Kosei Yamauchi, Hai‐Hua Huang, Jia‐Kai Sun, Zhi‐Mei Luo, Di‐Chang Zhong, Tong‐Bu Lu, Ken Sakai. A Molecular Cobalt Hydrogen Evolution Catalyst Showing High Activity and Outstanding Tolerance to CO and O 2. Angewandte Chemie 2019, 131 (32) , 11039-11043. https://doi.org/10.1002/ange.201904578
  59. Jia‐Wei Wang, Kosei Yamauchi, Hai‐Hua Huang, Jia‐Kai Sun, Zhi‐Mei Luo, Di‐Chang Zhong, Tong‐Bu Lu, Ken Sakai. A Molecular Cobalt Hydrogen Evolution Catalyst Showing High Activity and Outstanding Tolerance to CO and O 2. Angewandte Chemie International Edition 2019, 58 (32) , 10923-10927. https://doi.org/10.1002/anie.201904578
  60. Brian J. Cook, Richard L. Lord, Chun‐Hsing Chen, Kenneth G. Caulton. Gauging the Redox Non‐Innocence of a Highly Pi‐Acidic Bis‐Tetrazine Pincer Ligand. European Journal of Inorganic Chemistry 2019, 2019 (20) , 2535-2542. https://doi.org/10.1002/ejic.201900186
  61. Jitendrasingh Rajpurohit, Maheswaran Shanmugam. The molecular and electronic structure of an unusual cobalt NNO pincer ligand complex. Dalton Transactions 2019, 48 (21) , 7378-7387. https://doi.org/10.1039/C9DT00056A
  62. Kathrin Junge, Veronica Papa, Matthias Beller. Cobalt–Pincer Complexes in Catalysis. Chemistry – A European Journal 2019, 25 (1) , 122-143. https://doi.org/10.1002/chem.201803016
  63. Zhixin Chen, Tao Wang, Tingting Sun, Zhiyong Chen, Tian Sheng, Yu-Hao Hong, Zi-Ang Nan, Jun Zhu, Zhi-You Zhou, Haiping Xia, Shi-Gang Sun. Nickel Complexes with Non-innocent Ligands as Highly Active Electrocatalysts for Hydrogen Evolution. Chinese Journal of Chemistry 2018, 36 (12) , 1161-1164. https://doi.org/10.1002/cjoc.201800359
  64. Chithiraivel Balakrishnan, M.A. Neelakantan. Crystal structure and bio-catalytic potential of oxovanadium(IV) Schiff base complexes derived from 2-hydroxy-4-(prop-2-yn-1-yloxy)benzaldehyde and alicyclic/aromatic diamines. Inorganica Chimica Acta 2018, 469 , 503-514. https://doi.org/10.1016/j.ica.2017.09.060
  65. Thomas Simler, Sylvie Choua, Andreas A. Danopoulos, Pierre Braunstein. Reactivity of a dearomatised pincer Co II Br complex with PNC NHC donors: alkylation and Si–H bond activation via metal–ligand cooperation. Dalton Transactions 2018, 47 (24) , 7888-7895. https://doi.org/10.1039/C8DT01279B
  66. Chithiraivel Balakrishnan, M. Theetharappan, P. Kowsalya, Satheesh Natarajan, M.A. Neelakantan, S.S. Mariappan. Biocatalysis, DNA–protein interactions, cytotoxicity and molecular docking of Cu(II), Ni(II), Zn(II) and V(IV) Schiff base complexes. Applied Organometallic Chemistry 2017, 31 (11) https://doi.org/10.1002/aoc.3776
  67. Liu Leo Liu, David A. Ruiz, Fatme Dahcheh, Guy Bertrand, Riccardo Suter, Aaron M. Tondreau, Hansjörg Grützmacher. Isolation of Au-, Co-η 1 PCO and Cu-η 2 PCO complexes, conversion of an Ir–η 1 PCO complex into a dimetalladiphosphene, and an interaction-free PCO anion. Chemical Science 2016, 7 (3) , 2335-2341. https://doi.org/10.1039/C5SC04504E
  68. Thomas W. Myers, Tobias J. Sherbow, James C. Fettinger, Louise A. Berben. Synthesis and characterization of bis(imino)pyridine complexes of divalent Mg and Zn. Dalton Transactions 2016, 45 (14) , 5989-5998. https://doi.org/10.1039/C5DT01541C
  69. Terry Chu, Lee Belding, Prashanth K. Poddutoori, Art van der Est, Travis Dudding, Ilia Korobkov, Georgii I. Nikonov. Unique molecular geometries of reduced 4- and 5-coordinate zinc complexes stabilised by diiminopyridine ligand. Dalton Transactions 2016, 45 (34) , 13440-13448. https://doi.org/10.1039/C6DT02001A
  70. Blake R. Reed, Sebastian A. Stoian, Richard L. Lord, Stanislav Groysman. The aldimine effect in bis(imino)pyridine complexes: non-planar nickel( i ) complexes of a bis(aldimino)pyridine ligand. Chemical Communications 2015, 51 (30) , 6496-6499. https://doi.org/10.1039/C5CC00203F
  71. Paul J. Chirik. Electronic Structures of Reduced Manganese, Iron, and Cobalt Complexes Bearing Redox-Active Bis(imino)pyridine Pincer Ligands. 2014,,, 189-212. https://doi.org/10.1002/9783527681303.ch7
  72. Kazuki Umehara, Shigeki Kuwata, Takao Ikariya. Synthesis, structures, and reactivities of iron, cobalt, and manganese complexes bearing a pincer ligand with two protic pyrazole arms. Inorganica Chimica Acta 2014, 413 , 136-142. https://doi.org/10.1016/j.ica.2013.12.041
  73. Scott P. Semproni, Crisita Carmen Hojilla Atienza, Paul J. Chirik. Oxidative addition and C–H activation chemistry with a PNP pincer-ligated cobalt complex. Chem. Sci. 2014, 5 (5) , 1956-1960. https://doi.org/10.1039/C4SC00255E
  74. Shaoli Wang, Weizhen Zhao, Xiang Hao, Baixiang Li, Carl Redshaw, Yuesheng Li, Wen-Hua Sun. 2-(1-{2,6-Bis[bis(4-fluorophenyl)methyl]-4-methylphenylimino}ethyl)-6-[1-(arylimino)ethyl]pyridylcobalt dichlorides: Synthesis, characterization and ethylene polymerization behavior. Journal of Organometallic Chemistry 2013, 731 , 78-84. https://doi.org/10.1016/j.jorganchem.2013.02.016
  75. Eugene Khaskin, Yael Diskin-Posner, Lev Weiner, Gregory Leitus, David Milstein. Formal loss of an H radical by a cobalt complex via metal–ligand cooperation. Chemical Communications 2013, 49 (27) , 2771. https://doi.org/10.1039/c3cc39049g
  76. Valerie A. Williams, Elliott B. Hulley, Peter T. Wolczanski, Kyle M. Lancaster, Emil B. Lobkovsky. Exploring the limits of redox non-innocence: pseudo square planar [{κ4-Me2C(CH2NCHpy)2}Ni]n (n = 2+, 1+, 0, −1, −2) favor Ni(ii). Chemical Science 2013, 4 (9) , 3636. https://doi.org/10.1039/c3sc50743b
  77. Konstantin P. Bryliakov, Evgenii P. Talsi. Frontiers of mechanistic studies of coordination polymerization and oligomerization of α-olefins. Coordination Chemistry Reviews 2012, 256 (23-24) , 2994-3007. https://doi.org/10.1016/j.ccr.2012.06.023
  78. Astrid Malassa, Christine Agthe, Helmar Görls, Matthias Westerhausen. Bis[μ- N -( tert -butyldimethylsilyl)- N -(pyridin-2-ylmethyl)amido]bis[methylcobalt(II)]. Acta Crystallographica Section E Structure Reports Online 2012, 68 (9) , m1167-m1168. https://doi.org/10.1107/S1600536812032321
  79. Fan He, Weizhen Zhao, Xiao-Ping Cao, Tongling Liang, Carl Redshaw, Wen-Hua Sun. 2-[1-(2,6-dibenzhydryl-4-chlorophenylimino)ethyl]-6-[1-aryliminoethyl]pyridyl cobalt dichlorides: Synthesis, characterization and ethylene polymerization behavior. Journal of Organometallic Chemistry 2012, 713 , 209-216. https://doi.org/10.1016/j.jorganchem.2012.05.020
  80. Alexander P. Sadimenko. Organometallic Complexes of Pyridyl Schiff Bases. 2012,,, 133-218. https://doi.org/10.1016/B978-0-12-396532-5.00004-4
  81. C. Moyses Araujo, Mark D. Doherty, Steven J. Konezny, Oana R. Luca, Alex Usyatinsky, Hans Grade, Emil Lobkovsky, Grigorii L. Soloveichik, Robert H. Crabtree, Victor S. Batista. Tuning redox potentials of bis(imino)pyridine cobalt complexes: an experimental and theoretical study involving solvent and ligand effects. Dalton Transactions 2012, 41 (12) , 3562. https://doi.org/10.1039/c2dt12195f
  82. Daniel Sieh, Mandy Schlimm, Lars Andernach, Friedrich Angersbach, Stefan Nückel, Julia Schöffel, Nevena Šušnjar, Peter Burger. Metal–Ligand Electron Transfer in 4d and 5d Group 9 Transition Metal Complexes with Pyridine, Diimine Ligands. European Journal of Inorganic Chemistry 2012, 2012 (3) , 444-462. https://doi.org/10.1002/ejic.201101072
  83. Tianpengfei Xiao, Shu Zhang, Baixiang Li, Xiang Hao, Carl Redshaw, Yue-Sheng Li, Wen-Hua Sun. Ferrous and cobaltous chloride complexes bearing 2-(1-(arylimino)methyl)-8-(1H-benzimidazol-2-yl)quinolines: Synthesis, characterization and catalytic behavior in ethylene polymerization. Polymer 2011, 52 (25) , 5803-5810. https://doi.org/10.1016/j.polymer.2011.10.037
  84. József S. Pap, Balázs Kripli, Michel Giorgi, József Kaizer, Gábor Speier. Redox properties of cobalt(II) complexes with isoindoline-based ligands. Transition Metal Chemistry 2011, 36 (5) , 481-487. https://doi.org/10.1007/s11243-011-9493-z
  85. Nicole M. G. Franssen, Joost N. H. Reek, Bas de Bruin. Pd-mediated carbenepolymerisation: activity of palladium( ii ) versus low-valent palladium. Polym. Chem. 2011, 2 (2) , 422-431. https://doi.org/10.1039/C0PY00249F
  86. Tianpengfei Xiao, Jingjuan Lai, Shu Zhang, Xiang Hao, Wen-Hua Sun. 2-(1-Aryliminopropylidene)quinolylcobalt(ii) dichlorides: synthesis, characterization and catalytic behaviour towards ethylene. Catalysis Science & Technology 2011, 1 (3) , 462. https://doi.org/10.1039/c1cy00028d
  87. Dipanwita Das, Tapan Kumar Mondal, Abhishek Dutta Chowdhury, Fritz Weisser, David Schweinfurth, Biprajit Sarkar, Shaikh M. Mobin, Francisco A. Urbanos, Reyes Jiménez-Aparicio, Goutam Kumar Lahiri. Valence and spin situations in isomeric [(bpy)Ru(Q′)2]n (Q′ = 3,5-di-tert-butyl-N-aryl-1,2-benzoquinonemonoimine). An experimental and DFT analysis. Dalton Transactions 2011, 40 (33) , 8377. https://doi.org/10.1039/c1dt10609k