Amending the Anisotropy Barrier and Luminescence Behavior of Heterometallic Trinuclear Linear [MIILnIIIMII] (LnIII=Gd,Tb, Dy; MII=Mg/Zn) Complexes by Change from Divalent Paramagnetic to Diamagnetic Metal Ions |
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| Authors: | Dr Sourav Das K S Bejoymohandas Atanu Dey Sourav Biswas Dr M L P Reddy Dr Roser Morales Prof Eliseo Ruiz Dr Silvia Titos‐Padilla Prof Enrique Colacio Prof Vadapalli Chandrasekhar |
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| Affiliation: | 1. Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur‐208016 (India) http://www.iitk.ac.in;2. Materials Science and Technology Division, National Institute for Interdisciplinary Science and Technology (NIIST), Council of Scientific and Industrial Research (CSIR), Thiruvananthapuram 695 019 (India) http://www.niist.res.in/english/;3. Academy of Scientific and Innovative Research (AcSIR), New Delhi 110001 (India) http://acsir.res.in/;4. Departament de Química Inorgànica and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, E‐08028 Barcelona (Spain);5. Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, Avenida de Fuentenueva s/n, 18071 Granada (Spain) http://www.ugr.es;6. National Institute of Science Education and Research, Institute of Physics Campus, SachivalayaMarg, PO: Sainik School, Bhubaneswar ‐ 751 005 (India) http://www.niser.ac.in |
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| Abstract: | The sequential reaction of a multisite coordinating compartmental ligand 2‐(2‐hydroxy‐3‐(hydroxymethyl)‐5‐methylbenzylideneamino)‐2‐methylpropane‐1,3‐diol] (LH4) with appropriate lanthanide salts followed by the addition of Mg(NO3)2] ? 6 H2O or Zn(NO3)2] ? 6 H2O in a 4:1:2 stoichiometric ratio in the presence of triethylamine affords a series of isostructural heterometallic trinuclear complexes containing Mg2Ln]3+ (Ln=Dy, Gd, and Tb) and Zn2Ln]3+ (Ln=Dy, Gd, and Tb) cores. The formation of these complexes is demonstrated by X‐ray crystallography as well as ESI‐MS spectra. All complexes are isostructural possessing a linear trimetallic core with a central lanthanide ion. The comprehensive studies discussed involve the synthesis, structure, magnetism, and photophysical properties on this family of trinuclear Mg2Ln]3+ and Zn2Ln]3+ heterometallic complexes. Mg2Dy]3+ and Zn2Dy]3+ show slow relaxation of the magnetization below 12 K under zero applied direct current (dc) field, but without reaching a neat maximum, which is due to the overlapping with a faster quantum tunneling relaxation mediated through dipole–dipole and hyperfine interactions. Under a small applied dc field of 1000 Oe, the quantum tunneling is almost suppressed and temperature and frequency dependent peaks are observed, thus confirming the single‐molecule magnet behavior of complexes Mg2Dy]3+ and Zn2Dy]3+. |
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| Keywords: | coordination chemistry heterometallic complexes luminescence magnetic properties photochemistry single‐molecule magnets |
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