Strong Ferromagnetic Exchange Coupling Mediated by a Bridging Tetrazine Radical in a Dinuclear Nickel Complex.

The radical bridged compound [(Ni(TPMA))2-μ-bmtz•-](BF4)3·3CH3CN (bmtz = 3,6-bis(2'-pyrimidyl)-1,2,4,5-tetrazine, TPMA = tris(2-pyridylmethyl)amine) exhibits strong ferromagnetic exchange between the S = 1 NiII centers and the bridging S = 1/2 bmtz radical with J = 96 ± 5 cm-1 (-2JNi-radSNiSrad). DFT calculations support the existence of strong ferromagnetic exchange.

[1]  K. Vignesh,et al.  Putting a New Spin on Supramolecular Metallacycles: Co3 Triangle and Co4 Square Bearing Tetrazine-Based Radicals as Bridges. , 2017, Journal of the American Chemical Society.

[2]  L. Ungur,et al.  Strong ferromagnetic exchange coupling in a {Ni} cluster mediated through an air-stable tetrazine-based radical anion. , 2017, Chemical communications.

[3]  Silvia Gómez-Coca,et al.  An air stable radical-bridged dysprosium single molecule magnet and its neutral counterpart: redox switching of magnetic relaxation dynamics. , 2017, Chemical communications.

[4]  Hans‐Jörg Himmel,et al.  Radical Monocationic Guanidino-Functionalized Aromatic Compounds (GFAs) as Bridging Ligands in Dinuclear Metal Acetate Complexes: Synthesis, Electronic Structure, and Magnetic Coupling. , 2016, Inorganic chemistry.

[5]  K. Dunbar,et al.  Strong Direct Magnetic Coupling in a Dinuclear Co(II) Tetrazine Radical Single-Molecule Magnet. , 2015, Chemistry.

[6]  Y. Filinchuk,et al.  Anion-induced Ag(I) self-assemblies with electron deficient aromatic ligands: anion-π-system interactions as a driving force for templated coordination networks. , 2015, Chemical communications.

[7]  K. Vignesh,et al.  What controls the magnetic exchange interaction in mixed- and homo-valent Mn7 disc-like clusters? A theoretical perspective. , 2015, Chemistry.

[8]  K. Vignesh,et al.  Neutral diiron(III) complexes with Fe₂(μ-E)₂ (E = O, S, Se) core structures: reactivity of an iron(I) dimer towards chalcogens. , 2015, Dalton transactions.

[9]  D. J. Brook.  Coordination Chemistry of Verdazyl Radicals , 2015 .

[10]  G. Rajaraman,et al.  Magnetic anisotropy of mononuclear Ni(II) complexes: on the importance of structural diversity and the structural distortions. , 2014, Chemistry.

[11]  G. Rajaraman,et al.  Solvate-dependent spin crossover and exchange in cobalt(II) oxazolidine nitroxide chelates. , 2014, Inorganic chemistry.

[12]  Jesse G. Park,et al.  An azophenine radical-bridged Fe2 single-molecule magnet with record magnetic exchange coupling. , 2013, Journal of the American Chemical Society.

[13]  D. Liao,et al.  Unprecedented nitronyl nitroxide bridged 3d-4f complexes: structure and magnetic properties. , 2013, Inorganic chemistry.

[14]  L. Chibotaru,et al.  A dinuclear cobalt complex featuring unprecedented anodic and cathodic redox switches for single-molecule magnet activity. , 2013, Journal of the American Chemical Society.

[15]  Joseph M. Zadrozny,et al.  Exchange coupling and magnetic blocking in bipyrimidyl radical-bridged dilanthanide complexes. , 2012, Journal of the American Chemical Society.

[16]  G. Rajaraman,et al.  Is a radical bridge a route to strong exchange interactions in lanthanide complexes? A computational examination. , 2012, Chemical communications.

[17]  C. Forsyth,et al.  Supramolecular architecture of silver(I) coordination polymers containing polydentate N-donor ligands , 2012 .

[18]  Jian Wu,et al.  Metal complexes of bridging neutral radical ligands: pymDTDA and pymDSDA. , 2012, Inorganic chemistry.

[19]  J. Veciana,et al.  Playing with organic radicals as building blocks for functional molecular materials. , 2012, Chemical Society reviews.

[20]  M. Shatruk,et al.  Anion-templated self-assembly of highly stable Fe(II) pentagonal metallacycles with short anion-π contacts. , 2011, Chemical communications.

[21]  J. Long,et al.  A N2(3-) radical-bridged terbium complex exhibiting magnetic hysteresis at 14 K. , 2011, Journal of the American Chemical Society.

[22]  J. Long,et al.  Strong exchange and magnetic blocking in N₂³⁻-radical-bridged lanthanide complexes. , 2011, Nature chemistry.

[23]  M. Hundley,et al.  Strong ferromagnetic metal-ligand exchange in a nickel bis(3,5-dipyridylverdazyl) complex. , 2010, Chemical communications.

[24]  S. Kaizaki.  Coordination effects of nitroxide radicals in transition metal and lanthanide complexes , 2006 .

[25]  C. Duboc,et al.  Complexes of [Re(CO)3Cl] with different oxidation states of the polyfunctional bmtz/H2bmtz ligand system (bmtz=3,6-bis(2-pyrimidyl)-1,2,4,5-tetrazine) , 2004 .

[26]  E. Ruiz.  Theoretical Study of the Exchange Coupling in Large Polynuclear Transition Metal Complexes Using DFT Methods , 2004 .

[27]  L. Thompson,et al.  Verdazyl radicals as oligopyridine mimics: structures and magnetic properties of M(II) complexes of 1,5-dimethyl-3-(2,2'-bipyridin-6-yl)-6-oxoverdazyl (M = Mn, Ni, Cu, Zn). , 2003, Inorganic chemistry.

[28]  L. Thompson,et al.  Synthesis and coordination chemistry of a water-soluble verdazyl radical. structures and magnetic properties of M(H2O)2(vdCO2)(2).2H2O (M = Co, Ni; vdCO2 = 1,5-dimethyl-6-oxo-verdazyl-3-carboxylate). , 2002, Chemical communications.

[29]  W. Kaim,et al.  Stufenweise und chemisch reversible Reduktion von Zweikernkomplexen {(μ-bmtz)[MCl(η6-Cym)]2}[PF6]2 (M = Ru, Os; bmtz = 3,6-Bis(2′-pyrimidyl)1,2,4,5-tetrazin) mit bis zu sechs Elektronen , 2001 .

[30]  A. Caneschi,et al.  Cobalt(II)-Nitronyl Nitroxide Chains as Molecular Magnetic Nanowires The financial support of Italian MURST and CNR and of Brazilian CNPq and FUJB is acknowledged. The support from the European Community through the TMR program 3MD (contract no ERB4061PL97-0197) is also acknowledged. , 2001, Angewandte Chemie.

[31]  W. Kaim,et al.  Dicopper(I) complexes with reduced states of 3,6-bis(2'-pyrimidyl)-1,2,4,5-tetrazine: crystal structures and spectroscopic properties of the free ligand, a radical species, and a complex of the 1,4-dihydro form. , 2001, Inorganic Chemistry.

[32]  A. L. Thompson,et al.  Strong Ferromagnetic and Antiferromagnetic Exchange Coupling between Transition Metals and Coordinated Verdazyl Radicals , 2000 .

[33]  Christoph Janiak,et al.  A critical account on π–π stacking in metal complexes with aromatic nitrogen-containing ligands , 2000 .

[34]  A. Becke.  Density-functional thermochemistry. III. The role of exact exchange , 1993 .

[35]  A. Epstein,et al.  A Room-Temperature Molecular/Organic-Based Magnet , 1991, Science.