Department of Chemistry
University of Utah
Salt Lake City, UT 84112
Phone: (801) 585-5455
Fax: (801) 581-8433
Field of Interest: Inorganic and Materials Chemistry
Advisory Boards, Advanced Materials, Journal of Materials Chemistry, Chemistry - A European Journal, Inorganic Chemistry; Inorganic Synthesis Corporation
Editorial Board, CrystEngComm
Table of Contents
The earlier results on the decamethylferrocenium salt lead to a simple electron count-based theory to predict the type of the magnetic coupling and later to a more complex theory to scale the magnitude of the critical temperature, Tc. These concepts lead us to react bis(benzene)vanadium with TCNE. As bis(benzene)vanadium is isoelectronic to decamethylmanganocene, a new ferromagnet was anticipated. An exciting new magnet with an unexpected Tc above both room temperature and the material's thermal decomposition temperature was prepared. Most recently, we have identified a new class of molecule-based magnets based on Mn(porphin)(TCNE)(Tc = 16 K) and exciting new materials with unexpected magnetic properties are evolving.
Our materials preparation project benefits immensely from collaboration with physics groups. A strongly interactive collaboration exists with Prof. Arthur J. Epstein's group at Ohio State University. We work together to develop new materials and unravel the detailed physical properties of these novel magnets. We are also collaborating with Prof. C.W. (Paul) Chu at the University of Houston to study the temperature dependence of the critical temperature for those novel classes of materials. Muon spin resonance to independently determine Tc is being done with Prof. Y. (Toma) Uemura of Columbia University. Also, the experimental determination of the spin distribution crucial to understanding the spin coupling mechanism, as well as the magnetic structure, is being studied in collaboration with Prof. Jacques Schweizer of the Centre d'Etudes Nucleaires in Grenoble, France. This recent collaboration has already yielded the spin distribution for the radical anion of TCNE. Each sp2-C has 33% of the spin while each N has 13%, whereas each sp-C has -5% of the spin.
Our proposed multidisciplinary research builds upon these and other accomplishments over the past few years, and targets projects to understand the structure-function relationship to ultimately enable the preparation of stable, technologically useful, high Tc molecule-based and/or polymeric magnets. Additionally, we have programs evolving in the area of new materials with high electrical conductivity.
"Designer Magnets," J. S. Miller and A. J. epstein, Chem. & Engg. News, 73(#40), 30 (1995).
"The Weak Effect on Tc with Increased Interchain Distances. The Structure and magnetic Properties of meso-Tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphinatomanganese(III) Tetracyanoethenide, [MnIIITP'P]+[TCNE].-," A. Bohm, C. Vazquez, R. S. McLean, J. C. Calabrese, S. E. Kalm, J. L. Manson, A. J. Epstein, and J. S. Miller, Inorg. Chem. 35, 3083 (1996).
"The Importance of Magnetic Coupling via Atoms with Large Spin Densities. The Structure and Magnetic Properties of meso-Tetrakis-(4-t-butylphenyl)-porphinatomanganese(III) Hexacyanobutadienide, [MnIIITButPP]+[C4(CN)6].-," K.-i. Sugiura, A.M. Arif, D. K. Rittenberg, J. Schweizer, L. Ohrstrom, A.J. Epstein and J.S. Miller, Chem. Eur. J. 3, 138 (1997).
"Isolation and Structural Determination of [(1,1,2,2-tetracyano-1,2-ethanediyl)-bis[imino(cyanomethylene)]]bis[cyanamide] ion(2-), [C12N12]2- - A New Cyanocarbon," W. E. Buschmann, A. M. Arif, and Joel S. Miller, J. Chem. Soc., Chem. Commun. 2353 (1995).
"Improved Synthesis of the V(TCNE)x.y(solvent) Room-Temperature Magnet: Doubling of the Magnetization at Room Temperature," J. Zhang, P. Zhou, W. B. Brinckerhoff, A. J. Epstein, C. Vazquez, R. S. McLean, and J. S. Miller, ACS Sym. Ser.644, 311 (1996).
"Electron Transfer Salt-Based Conductors, Superconductors and Magnets," P. Cassoux and J.S. Miller, in Chemistry of Advanced Materials: A New Discipline, L.V Interrante and M. Hampton-Smith, Eds.; VCH; New York (in press, 1997). Magnets based on M-CN linkages are also being studied.
"Molecular Magnets -An Emerging Area of Materials Chemistry," A.J. Epstein and J.S. Miller, Adv. Chem. Ser. 245, 161 (1995).
"Experimental Determination of the Spin Density in the Tetracyanoethenide Free Radical, [TCNEI-, by Single Crystal Polarized Neutron Diffraction and ab initio Calculations. Evidence for Bending-Back of a pi* Orbital," A. Zheludev, A. Grand, E. Ressouche, J. Schweizer, B. Morin, A.J. Epstein, D.A. Dixon and J.S. Miller, Angew. Chem. 33, 1327 (1994).
"Organic and Organometallic Magnetic Materials-Designer Magnets," J.S. Miller and A.J. Epstein, Angew Chem. Internat. Ed. 33, 385 (1994).
"Pressure Dependence of Magnetic Ordering Temperature for Decamethylferrocenium Tetracyanoethenide," Z. J. Huang, E. Cheng, Y. T. Ren, Y.Y. Xue, C.W Chu and J.S. Miller, J. Appl. Phys. 73, 6563 (1993).
"Room Temperature Cooperative Behavior in a Molecular-Based Material," J.S. Miller, G.T. Yee, J.M. Manriquez and A.J. Epstein, in the Proceedings of Nobel Symposium #NS-81, Conjugated Polymers and Related Materials: The Interconnection of Chemical and Electronic Structure, Oxford University Press, 461 (1993).
"Cyanil, Synthesis and Characterization of the Strongest Isolated Electron Acceptor and its Reduced Forms," C. Vazquez, J.C. Calabrese, D.A. Dixon and J.S. Miller, J. Org. Chem. 58, 65 (1993).
"meso(Tetraphenylporphianato)manganese III Tetracyanoethenide [MnIIITPP][TCNE].-. A Linear Chain Magnet with a Tc of 18 K," J.S. Miller, J.C. Calabrese, R.S. McLean and A.J. Epstein, Adv. Mater. 4, 498 (1992).
"The Quest for Magnetic Polymers - Caveat Emptor," J.S. Miller, Adv. Mater. 4, 298; 435 (1992).
"Decamethylmanganocenium Tetracyanoethenide, 3[Mn(C5Me5)2]:+[TCNE].- A Molecular Ferromagnet with an 8.8 K Tc." G.T Yee, J.M. Manriquez, D.A. Dixon, R.S. McLean, D.M. Groski, R.B. Flippen, K.S. Narayan, A.J. Epstein and J.S. Miller, Adv. Mater. 3, 309 (1991).
"A Room Temperature Molecular/Organic-Based Magnet," J.M. Manriquez, G.T. Yee, R.S. McLean, A.J. Epstein and J.S. Miller, Science 252, 1415 (1991).
"Hexaazaoctadecahydrocoronene, HOC. Structural and Physical Properties of [HOC]n (n = 0, 1+, 2+, 3+, 4+)," J.S. Miller, D.A. Dixon, J.C. Calabrese, C. Vazquez, R.J. Krusic, M.D. Ward, E. Wasserman and R.L. Harlow, J. Am. Chem. Soc. 112, 381 (1990).
"Molecular Electronics?" J. S. Miller, Adv. Mater. 2, 378; 495; 601 (1990).
"Prescription for Stabilization of Ferromagnetic Exchange in Molecular Solids via Admixing of the Ground State with a Virtual Charge Transfer Excited State," J. S. Miller and A. J. Epstein, J. Am. Chem. Soc. 109, 3850 (1987).
"One-Dimensional Inorganic Complexes," J. S. Miller and A. J. Epstein, Prog. Inorg. Chem.20,
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