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Cyclic [Cu-biRadical]2 Secondary Building Unit in 2p-3d and 2p-3d-4f Complexes: Crystal Structure and Magnetic Properties. Molecules 2023; 28:molecules28062514. [PMID: 36985497 PMCID: PMC10058193 DOI: 10.3390/molecules28062514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/07/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
Employing the new nitronyl nitroxide biradical ligand biNIT-3Py-5-Ph (2-(5-phenyl-3-pyridyl)-bis(4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide)), a 16-spin Cu-radical complex, [Cu8(biNIT-3Py-5-Ph)4(hfac)16] 1, and three 2p-3d-4f chain complexes, {[Ln(hfac)3][Cu(hfac)2]2(biNIT-3Py-5-Ph)2}n (LnⅢ= Gd 2, Tb 3, Dy 4; hfac = hexafluoroacetylacetonate), have been prepared and characterized. X-ray crystallographic analysis revealed in all derivatives a common cyclic [Cu-biNIT]2 secondary building unit in which two bi-NIT-3Py-5-Ph biradical ligands and two CuII ions are associated via the pyridine N atoms and NO units. For complex 1, two such units assemble with four additional CuII ions to form a discrete complex involving 16 S = 1/2 spin centers. For complexes 2–4, the [Cu-biNIT]2 units are linked by LnIII ions via NO groups in a 1D coordination polymer. Magnetic studies show that the coordination of the aminoxyl groups with Cu or Ln ions results in behaviors combining ferromagnetic and antiferromagnetic interactions. No slow magnetic relaxation behavior was observed for Tb and Dy derivatives.
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Molčanov K, Milašinović V, Kojić-Prodić B, Maltar-Strmečki N, You J, Šantić A, Kanižaj L, Stilinović V, Fotović L. Semiconductive 2D arrays of pancake-bonded oligomers of partially charged TCNQ radicals. IUCRJ 2022; 9:449-467. [PMID: 35844480 PMCID: PMC9252159 DOI: 10.1107/s2052252522004717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Multicentre two-electron (mc/2e or 'pancake bonding') bonding between 7,7,8,8-tetra-cyano-quinodi-methane (TCNQ) radical anions was studied on its 14 novel salts with planar organic cations. The formal charges of the TCNQδ- moieties are -1/2 and -2/3, and they form mc/2e bonded dimers, trimers and tetramers which are further stacked into extended arrays. Multicentre bonding within these oligomers is characterized by short interplanar separations of 2.9-3.2 Å; distances between the oligomers are larger, typically >3.3 Å. The stacks are laterally connected by C-H⋯N hydrogen bonding, forming 2D arrays. The nature of mc/2e bonding is characterized by structural, magnetic and electrical data. The compounds are found to be semiconductors, and high conductivity [10-2 (Ω cm)-1] correlates with short interplanar distances between pancake-bonded oligomers.
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Affiliation(s)
- Krešimir Molčanov
- Department of Physical Chemistry, Rudjer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Valentina Milašinović
- Department of Physical Chemistry, Rudjer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Biserka Kojić-Prodić
- Department of Physical Chemistry, Rudjer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Nadica Maltar-Strmečki
- Department of Physical Chemistry, Rudjer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Jiangyang You
- Department of Physical Chemistry, Rudjer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Ana Šantić
- Department of Materials Chemistry, Rudjer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Lidija Kanižaj
- Department of Materials Physics, Rudjer Bošković Institute, Bijenička 54, Zagreb 10000, Croatia
| | - Vladimir Stilinović
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, Zagreb HR-10000, Croatia
| | - Luka Fotović
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, Zagreb HR-10000, Croatia
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