Influence of HF2- geometry on magnetic interactions elucidated from polymorphs of the metal-organic framework [Ni(HF2)(pyz)2]PF6 (pyz = pyrazine).

A tetragonal polymorph of [Ni(HF(2))(pyz)(2)]PF(6) (designated β) is isomorphic to its SbF(6)-congener at 295 K and features linear Ni-FHF-Ni pillars. Enhancements in the spin exchange (J(FHF) = 7.7 K), Néel temperature (T(N) = 7 K), and critical field (B(c) = 24 T) were found relative to monoclinic α-PF(6). DFT reveals that the HF(2)(-) bridges are significantly better mediators of magnetic exchange than pyz (J(pyz)), where J(FHF) ≈ 3J(pyz), thus leading to quasi-1D behavior. Spin density resides on all atoms of the HF(2)(-) bridge whereas N-donor atoms of the pyz ring bear most of the density.

[1]  P. Jena,et al.  Pressure-induced local structure distortions in Cu(pyz)F2(H2O)2. , 2011, Inorganic chemistry.

[2]  R. E. Del Sesto,et al.  Structural, electronic, and magnetic properties of quasi-1D quantum magnets [Ni(HF2)(pyz)2]X (pyz = pyrazine; X = PF6(-), SbF6(-)) exhibiting Ni-FHF-Ni and Ni-pyz-Ni spin interactions. , 2011, Inorganic chemistry.

[3]  S. Blundell,et al.  Magnetic order in quasi-two-dimensional molecular magnets investigated with muon-spin relaxation , 2011, 1104.3505.

[4]  S. Blundell,et al.  [Cu(HF2)2 (pyrazine)]n: a rectangular antiferromagnetic lattice with a spin exchange path made up of two different FHF- bridges. , 2011, Angewandte Chemie.

[5]  K. Chapman,et al.  Pressure-induced sequential orbital reorientation in a magnetic framework material. , 2011, Angewandte Chemie.

[6]  J. Schlueter,et al.  Effect of deuteration on the structural and magnetic properties of CuF2(H2O)2(pyrazine) , 2010 .

[7]  J. Schlueter,et al.  Crystal Structure and Antiferromagnetic Ordering of Quasi-2D [Cu(HF2)(pyz)2]TaF6 (pyz=pyrazine) , 2010 .

[8]  E. Čižmár,et al.  Magnetic properties of the quasi-two-dimensional s=1/2 Heisenberg antiferromagnet [Cu(pyz){sub sub 2}(HF{sub 2})]PF{sub 6}. , 2009, 0911.4402.

[9]  P. Comba,et al.  Cyanometalate-bridged oligonuclear transition metal complexes-Possibilities for a rational design of SMMs , 2009 .

[10]  M. Orio,et al.  Magnetic and spectroscopic properties of mixed valence manganese(III,IV) dimers: a systematic study using broken symmetry density functional theory. , 2009, Inorganic chemistry.

[11]  S. Blundell,et al.  Strong H...F hydrogen bonds as synthons in polymeric quantum magnets: structural, magnetic, and theoretical characterization of [Cu(HF2)(pyrazine)2]SbF6, [Cu2F(HF)(HF2)(pyrazine)4](SbF6)2, and [CuAg(H3F4)(pyrazine)5](SbF6)2. , 2009, Journal of the American Chemical Society.

[12]  F. Neese.  Prediction of molecular properties and molecular spectroscopy with density functional theory: From fundamental theory to exchange-coupling , 2009 .

[13]  S. Blundell,et al.  Experimental and Theoretical Characterization of the Magnetic Properties of CuF2(H2O)2(pyz) (pyz = pyrazine): A Two-Dimensional Quantum Magnet Arising from Supersuperexchange Interactions through Hydrogen Bonded Paths , 2008 .

[14]  J. Schlueter,et al.  Experimentally determining the exchange parameters of quasi-two-dimensional Heisenberg magnets , 2008 .

[15]  S. Blundell,et al.  Isotope Effect In Quasi-Two-Dimensional Metal-Organic Antiferromagnets , 2008, 0807.1506.

[16]  S. Blundell,et al.  Muon-fluorine entangled states in molecular magnets. , 2007, Physical review letters.

[17]  G. Jameson,et al.  Two-dimensional heisenberg antiferromagnets: syntheses, X-ray structures, and magnetic behavior of [Cu(pz)2](ClO4)2, [Cu(pz)2](BF4)2, and [Cu(pz)2(NO3)](PF6). , 2007, Inorganic chemistry.

[18]  S. Blundell,et al.  Magnetic Order In The S=1/2 Two-Dimensional Molecular Antiferromagnet Copper Pyrazine Perchlorate Cu(Pz)(2)(Clo4)(2) , 2006, cond-mat/0612317.

[19]  S. Blundell,et al.  [Cu(HF2)(pyz)2]BF4 (pyz = pyrazine): long-range magnetic ordering in a pseudo-cubic coordination polymer comprised of bridging HF2- and pyrazine ligands. , 2006, Chemical communications.

[20]  E. Francisco,et al.  The nature of the hydrogen bond: a synthesis from the interacting quantum atoms picture. , 2006, The Journal of chemical physics.

[21]  F. Neese,et al.  Dimanganese catalase—spectroscopic parameters from broken-symmetry density functional theory of the superoxidized MnIII/MnIV state , 2005, JBIC Journal of Biological Inorganic Chemistry.

[22]  A. Sandvik,et al.  Specific heat of quasi-two-dimensional antiferromagnetic Heisenberg models with varying interplanar couplings , 2003, cond-mat/0306046.

[23]  J. L. Smith,et al.  Critical examination of heat capacity measurements made on a Quantum Design physical property measurement system , 2003 .

[24]  J. Bendix.  2.55 – Ligfield , 2003 .

[25]  S. Mitra,et al.  A Pyrazine-Bridged Ni(II) Coordination Polymer , 2002 .

[26]  Alan A. Coelho,et al.  Indexing of powder diffraction patterns by iterative use of singular value decomposition , 2002 .

[27]  M. James.  The Structure and Magnetic Properties of the Two-Dimensional Di-Pyrazine Bridged Polymers M(pz)2Br2 (M = FeII, CoII, NiII) , 2002 .

[28]  S. V. Larionov,et al.  Monodentate and Bridging Bidentate Functions of Pyrazine in the Crystal Structures of [Ni(Pz)2{(i-C4H9)2PS2}2] and [Ni(Pz){(i-C4H9)2PS2}2]n , 2001 .

[29]  Y. Kitagawa,et al.  Ab initio computations of effective exchange integrals for H–H, H–He–H and Mn2O2 complex: comparison of broken-symmetry approaches , 2000 .

[30]  S. Blundell.  Spin-polarized muons in condensed matter physics , 1999, cond-mat/0207699.

[31]  R. Pastorek,et al.  Reactions of bis(isoproplxanthato)nickel(II) with nitrogen or oxygen donor ligands—III. X-ray crystal structure of the complex with pyrazine☆ , 1996 .

[32]  D. Proserpio,et al.  Novel Networks of Unusually Coordinated Silver(I) Cations: The Wafer-Like Structure of [Ag(pyz)2][Ag2(pyz)5](PF6)3·2G and the Simple Cubic Frame of [Ag(pyz)3](SbF6)† , 1995 .

[33]  Robert C. Thompson,et al.  Antiferromagnetism and metamagnetism in 1,4-diazine and pyridine complexes of nickel(II) , 1995 .

[34]  J. Bendix,et al.  Accurate empirical spin-orbit coupling parameters .zeta.nd for gaseous ndq transition metal ions. The parametrical multiplet term model , 1993 .

[35]  T. Yosida,et al.  Magnetization Measurement of NENP and NINO in High Magnetic Field , 1992 .

[36]  Hans W. Horn,et al.  Fully optimized contracted Gaussian basis sets for atoms Li to Kr , 1992 .

[37]  M. Odelius,et al.  Simple non-empirical calculations of the zero field splitting in transition metal systems , 1991 .

[38]  Takahashi,et al.  Effect of the Haldane gap on quasi-one-dimensional systems. , 1990, Physical review. B, Condensed matter.

[39]  I. Affleck.  Quantum spin chains and the Haldane gap , 1988 .

[40]  R. Overill,et al.  Hydrogen-bond energies of FHF– and HOHF–. Ab initio studies of strong hydrogen bonds involving fluoride, using improved fluoride energies , 1983 .

[41]  T. Mcmahon,et al.  GAS-PHASE BIFLUORIDE ION. AN ION CYCLOTRON RESONANCE DETERMINATION OF THE HYDROGEN BOND ENERGY IN FLUORIDE ION (FHF-) FROM GAS-PHASE FLUORIDE TRANSFER EQUILIBRIUM MEASUREMENTS , 1982 .

[42]  A. Gleizes,et al.  Crystal structures, magnetic anisotropy properties and orbital interactions in catena-(.mu.-nitrito)-bis(ethylenediamine)nickel(II) perchlorate and triiodide , 1982 .

[43]  Louis Noodleman,et al.  Valence bond description of antiferromagnetic coupling in transition metal dimers , 1981 .

[44]  Deborah J. Jones,et al.  Strong hydrogen bonding in the polyfluorides: ab initio calculations and a new method of preparing potassium hydrogendifluoride , 1981 .

[45]  J. Emsley.  Very strong hydrogen bonding , 1980 .

[46]  A. Miedema,et al.  Experiments on simple magnetic model systems , 1978 .

[47]  Robert J. Birgeneau,et al.  Neutron Scattering Investigation of Phase Transitions and Magnetic Correlations in the Two-Dimensional Antiferromagnets K 2 Ni F 4 , Rb 2 Mn F 4 , Rb 2 Fe F 4 , 1970 .

[48]  C. E. Schäffer.  A perturbation representation of weak covalent bonding , 1968 .

[49]  C. Jørgensen,et al.  The angular overlap model, an attempt to revive the ligand field approaches , 1965 .

[50]  H. Yamatera.  On the Absorption Spectra of Hexamminecobalt (III) and Related Complexes. II. Theoretical Study on Shifting and Spilitting of the First and the Second Band Due to Substitution of Ligands , 1958 .