Iron spin-crossover compounds: from fundamental studies to practical applications.

Over the past five years, the spin-crossover (SCO) phenomenon has experienced a clear new lease of interest from the scientific community coinciding with the recent publication of remarkable new advances. This perspective paper describes five illustrative examples of SCO systems, published during the past twelve months, showing new aspects of the unique and very appealing behaviour of these molecular switches, which may find interesting applications in the near future.

[1]  M. Halcrow.  The spin-states and spin-transitions of mononuclear iron(II) complexes of nitrogen-donor ligands , 2007 .

[2]  P. Gütlich,et al.  Light-induced excited spin state trapping in a transition-metal complex: The hexa-1-propyltetrazole-iron (II) tetrafluoroborate spin-crossover system , 1984 .

[3]  N. Matsumoto,et al.  One-dimensional Polynuclear Spin-crossover Iron(III) Complex Axially Bridged by 1,3-Bis(4-pyridyl)propane , 2006 .

[4]  Christophe Vieu,et al.  A Combined Top‐Down/Bottom‐Up Approach for the Nanoscale Patterning of Spin‐Crossover Coordination Polymers , 2007 .

[5]  P. Gütlich,et al.  Remarkable steric effects and influence of monodentate axial ligands l on the spin-crossover properties of trans-[FeII(N4 ligand)L] complexes. , 2007, Inorganic chemistry.

[6]  A. Hauser,et al.  Intersystem crossing in Fe(II) coordination compounds , 1991 .

[7]  Andreas Hauser,et al.  Reversibility of light-induced excited spin state trapping in the Fe(ptz)6(BF4)2, and the Zn1−xFex(ptz)6(BF4)2 spin-crossover systems , 1986 .

[8]  F. Raymo.  Digital processing and communication with molecular switches , 2002 .

[9]  J. Real,et al.  Spin‐Crossover 2D Metal–Organic Frameworks with a Redox‐Active Ligand: [Fe(ttf‐adpy)2M(CN)4]·nH2O (ttf‐adpy = 4‐Tetrathiafulvalenylcarboxamidopyridine; MII = Ni, Pd, Pt) , 2009 .

[10]  J. Britten,et al.  Preparation and magnetic properties of iron(3+) spin-crossover complexes bearing a thiophene substituent: toward multifunctional metallopolymers. , 2009, Inorganic chemistry.

[11]  C. Massera,et al.  Coordination Dependence of Magnetic Properties within a Family of Related [FeII2] Complexes of a Triazine-Based Ligand , 2006 .

[12]  G. Molnár,et al.  Temperature and pressure effects on the spin state of ferric ions in the [Fe(sal2-trien)][Ni(dmit)2] spin crossover complex , 2008 .

[13]  Y. Tanabe,et al.  On the Absorption Spectra of Complex Ions II , 1954 .

[14]  P. Gütlich,et al.  Spin Crossover in Transition Metal Compounds II , 2004 .

[15]  Philipp Gütlich,et al.  Thermal and Optical Switching of Iron(II) Complexes , 1994 .

[16]  O. Kahn,et al.  Spin-Transition Polymers: From Molecular Materials Toward Memory Devices , 1998 .

[17]  R. V. Martinez,et al.  Nanoscale Deposition of Single‐Molecule Magnets onto SiO2 Patterns , 2007 .

[18]  G. Whitesides,et al.  Polymer microstructures formed by moulding in capillaries , 1995, Nature.

[19]  P. Gütlich,et al.  Correlations of the distribution of spin states in spin crossover compounds , 1999 .

[20]  A. Spek,et al.  A two-step spin crossover mononuclear iron(II) complex with a [HS-LS-LS] intermediate phase. , 2008, Chemical communications.

[21]  N. Matsumoto,et al.  Gradual Two-step Spin Crossover Behavior of Binuclear Iron(III) Complex Bridged by trans-1,2-Bis(4-pyridyl)ethylene , 2005 .

[22]  R. Metzger.  Unimolecular rectifiers and prospects for other unimolecular electronic devices. , 2004, Chemical record.

[23]  Y. Einaga,et al.  A spin-crossover cluster of iron(II) exhibiting a mixed-spin structure and synergy between spin transition and magnetic interaction. , 2009, Angewandte Chemie.

[24]  S. Kawata,et al.  Photo-induced spin transition of Iron(III) compounds with pi-pi intermolecular interactions. , 2009, Chemistry.

[25]  F. Biscarini,et al.  Nanopatterning Soluble Multifunctional Materials by Unconventional Wet Lithography , 2009 .

[26]  A. Fujishima,et al.  Iron(III) spin-crossover compounds with a wide apparent thermal hysteresis around room temperature. , 2001, Journal of the American Chemical Society.

[27]  Brian H. Marcus,et al.  Holographic data storage technology , 2000, IBM J. Res. Dev..

[28]  J. McGarvey,et al.  One shot laser pulse induced reversible spin transition in the spin-crossover complex [Fe(C4H4N2){Pt(CN)4}] at room temperature. , 2005, Angewandte Chemie.

[29]  James M. Tour,et al.  Molecular Scale Electronics: A Synthetic/Computational Approach to Digital Computing , 1998 .

[30]  N. Matsumoto,et al.  Inter- and Intrachain Spin-Transition Processes in One-Dimensional Polynuclear Iron(III) Complexes of N,N′-Ethylenebis(acetylacetonylideneimine) Bridged by 1,3-Bis(4-pyridyl)propane and 1,4-Bis(imidazolyl)butane , 2009 .

[31]  K. Chapman,et al.  Elucidating the mechanism of a two-step spin transition in a nanoporous metal-organic framework. , 2008, Journal of the American Chemical Society.

[32]  G. Molnár,et al.  Spin crossover and photomagnetism in dinuclear iron(II) compounds , 2007 .

[33]  L. Cambi,et al.  Über die magnetische Susceptibilität der komplexen Verbindungen , 1931 .

[34]  E. Jeanneau,et al.  Spin crossover in a family of iron(II) complexes with hexadentate ligands: ligand strain as a factor determining the transition temperature. , 2009, Chemistry.

[35]  A. Spek,et al.  [Fe(mu-btzmp)2(btzmp)2](ClO4)2: a doubly-bridged 1D spin-transition bistetrazole-based polymer showing thermal hysteresis behaviour. , 2007, Dalton transactions.

[36]  Giampiero Ruani,et al.  Micro- and nanopatterning of spin-transition compounds into logical structures. , 2008, Angewandte Chemie.

[37]  A. Spek,et al.  Influence of Sample Preparation, Temperature, Light, and Pressure on the Two-Step Spin Crossover Mononuclear Compound [Fe(bapbpy)(NCS)2] , 2009 .

[38]  G. Hearne,et al.  Thermally induced two-step, two-site incomplete 6A1<-->2T2 crossover in a mononuclear iron(III) phenolate-pyridyl Schiff-base complex: a rare crystallographic observation of the coexistence of pure S=5/2 and 1/2 metal centers in the asymmetric unit. , 2007, Inorganic chemistry.

[39]  Eugenio Coronado,et al.  Bistable Spin‐Crossover Nanoparticles Showing Magnetic Thermal Hysteresis near Room Temperature , 2007 .

[40]  Charles M. Lieber,et al.  Nanoelectronics from the bottom up. , 2007, Nature materials.

[41]  Y. Einaga,et al.  First observation of light-induced excited spin state trapping for an iron(III) complex [7] , 2000 .

[42]  R. Metzger.  Unimolecular rectifiers: methods and challenges. , 2006, Analytica chimica acta.

[43]  F. Biscarini,et al.  Nanostructuring Conjugated Materials by Lithographically Controlled Wetting , 2003 .

[44]  Switching of Molecular Spin States in Inorganic Complexes by Temperature, Pressure, Magnetic Field and Light: Towards Molecular Devices , 2004 .

[45]  Alberto Martínez-Otero,et al.  Surface-structured molecular sensor for the optical detection of acidity. , 2008, Langmuir : the ACS journal of surfaces and colloids.

[46]  K. Murray.  Advances in Polynuclear Iron(II), Iron(III) and Cobalt(II) Spin‐Crossover Compounds , 2008 .

[47]  Sergei S. Orlov,et al.  Holographic data storage systems , 1993, Proceedings of the IEEE.

[48]  P. Gütlich,et al.  Photomagnetic properties of an iron(II) low-spin complex with an unusually long-lived metastable LIESST state. , 2007, Inorganic chemistry.

[49]  J. Obel,et al.  An iron(II) spin-crossover complex with a 70 K wide thermal hysteresis loop. , 2008, Angewandte Chemie.

[50]  Philipp Gütlich,et al.  Spin-crossover nanocrystals with magnetic, optical, and structural bistability near room temperature. , 2008, Angewandte Chemie.

[51]  Olivier Kahn,et al.  Spin Transition Molecular Materials for displays and data recording , 1992 .

[52]  Odile Stéphan,et al.  Spin-crossover coordination nanoparticles. , 2008, Inorganic chemistry.

[53]  J. Real,et al.  Cooperative spin crossover behavior in cyanide-bridged Fe(II)-M(II) bimetallic 3D Hofmann-like networks (M = Ni, Pd, and Pt). , 2001, Inorganic chemistry.

[54]  T. Aida,et al.  Spin-crossover physical gels: a quick thermoreversible response assisted by dynamic self-organization. , 2007, Chemistry, an Asian journal.

[55]  W. Baker,et al.  Magnetic Properties of Some High-Spin Complexes of Iron(II) , 1964 .

[56]  S. Seki,et al.  Phonon coupled cooperative low-spin 1A1high-spin 5T2 transition in [Fe(phen)2(NCS)2] and [Fe(phen)2(NCSe)2] crystals , 1974 .

[57]  L. Cambi,et al.  Über die magnetische Susceptibilität der komplexen Verbindungen (II. Mitteil.). , 1933 .

[58]  C. de Graaf,et al.  Light-induced excited-state spin trapping in tetrazole-based spin crossover systems. , 2008, Journal of the American Chemical Society.

[59]  Jean-François Létard,et al.  Nanoparticles of iron(II) spin-crossover. , 2008, Chemical communications.

[60]  P. Gütlich,et al.  Multifunctionality in spin crossover materials , 2005 .

[61]  M. Halcrow.  Trapping and manipulating excited spin states of transition metal compounds. , 2008, Chemical Society reviews.

[62]  E. Molins,et al.  Spin transition in a triazine-based Fe(II) complex: variable-temperature structural, thermal, magnetic and spectroscopic studies , 2006 .

[63]  C. Massera,et al.  A Molecule‐Based Nanoporous Material Showing Tuneable Spin‐Crossover Behavior near Room Temperature , 2007 .

[64]  Masaaki Nakamura,et al.  Infinite Chain Structure and Steep Spin Crossover of a FeIII Complex with a N3O2 Pentadentate Schiff-Base Ligand and 4-Aminopyridine , 2005 .

[65]  Joachim,et al.  Nanoscale science of single molecules using local probes , 1999, Science.

[66]  P. Gütlich,et al.  Photoswitchable coordination compounds , 2001 .

[67]  M. Képénekian,et al.  Magnetic Bistability: from Microscopic to Macroscopic Understandings of Hysteretic Behavior using ab initio Calculations , 2009 .

[68]  G. Molnár,et al.  Single-laser-shot-induced complete bidirectional spin transition at room temperature in single crystals of (FeII(pyrazine)(Pt(CN)4)). , 2008, Journal of the American Chemical Society.

[69]  A. Spek,et al.  Counterion effect on the spin-transition properties of the cation [Fe(btzx)3]2+ (btzx=m-Xylylenebis(tetrazole)). , 2008, Chemistry.

[70]  Y. Einaga,et al.  A novel LIESST iron(II) complex exhibiting a high relaxation temperature. , 2001, Inorganic chemistry.

[71]  Jan Reedijk,et al.  Two-step spin-transition iron(III) compound with a wide [high spin-low spin] plateau. , 2009, Inorganic chemistry.

[72]  Masaaki Ohba,et al.  Bidirectional chemo-switching of spin state in a microporous framework. , 2009, Angewandte Chemie.