The Rational Design and Preparation of Cyanometalate-Based Single-Molecule Magnets

• Applicant: Professor Dr. Peter Comba
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2010 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 166831430

• Final Report Year: 2014

Final Report Abstract

So far, our studies with lanthanide complexes have shown that the ligand field at the lanthanide center is of central importance for the optimization of SMMs. This was quite astonishing for us because, with a few hundred wavenumbers, the ligand field of lanthanide complexes is known to be small. However, this small effect is sufficient to significantly influence the structure and energy of the states such that, in a highly symmetrical axial field, the unfavorable fast relaxation is quenched, while in lower symmetry, there is fast relaxation of the magnetization. In order to quench fast relaxation, the three main relaxation processes (a. thermal relaxation, b. tunneling and c. Orbach relaxation) need to be quenched. Our results indicate that a few hundred wavenumbers in the axial ligand field are sufficient to quench the thermal relaxation a. This also leads to a small transversal moment (small gx and gy values, related to the tunneling b). A small deviation from a single axis between the Kramers doublets in the case of DyIII quenches the Orbach relaxation c.

Publications

• in “Structure and Function”, Comba, P. (Ed), Springer 2010, 53-85. 'Magnetic anisotropy in cyanide complexes of first row transition metal ions'
  Atanasov, M.; Comba, P.
  
• Inorg. Chem. 2011, 50, 6890-6901. 'Cyano-bridged homodinuclear copper(II) complexes'
  Atanasov, M.; Comba, P.; Hanson, G. R.; Hausberg, S.; Helmle, S.; Wadepohl, H.
  
• Inorg. Chem. 2012, 51, 12324-12335. 'Zero-field splitting of a series of structurally related mononuclear nickel(II)-bispidine complexes'
  Atanasov, M.; Comba, P.; Helmle, S.; Müller, D.; Neese, F.
  
• Inorg. Chem. 2012, 51, 9357-9368. 'Cyanide-bridged FeIII-CuII complexes: Jahn-Teller isomerism and its influence on the magnetic properties'
  Atanasov, M.; Comba, P.; Helmle, S.
  
• Dalton Trans. 2013, 42, 11066-11073. The computation of lipophilicities of 64Cu PET systems based on a novel approach for fluctuating charges'
  Comba, P.; Martin, B.; Sanyal, A.; Stephan, H.
  
• J. Comput. Chem. 2013, 34, 1598-1608. 'An efficient fluctuating charge model for transition metal complexes'
  Comba, P.; Martin, B.; Sanyal, A.
  
• Dalton Trans. 2014, 43, 5662-5666. 'Ferro- and antiferro-magnetic coupling in a chloride-bridged tetranuclear copper(II) complex'
  Grosshauser, M.; Comba, P.; Kim, J. Y.; Ohto, K.; Thuery, P.; Lee, Y. H.; Kim, Y.; Harrowfield, J.
  
• Magnetic interactions in a series of homodinuclear lanthanide complexes'. Inorg. Chem., 2015, 54 (23), pp 11247–11258
  Comba, P.; Grosshauser, M.; Müller, D.; Riley, M.; Wadepohl, H. + 5 weitere