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Monroe JC, Carvajal MA, Landee CP, Deumal M, Turnbull MM, Wikaira JL, Dawe LN. Approaching the isotropic spin-ladder regime: structure and magnetism of all-pyrazine-bridged copper(II)-based antiferromagnetic ladders. Dalton Trans 2022; 51:4653-4667. [PMID: 35212329 DOI: 10.1039/d1dt04219j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The crystal structure and magnetic properties of two all-pyrazine-bridged antiferromagnetic spin ladders are reported. The complexes, catena-(bis(3-X-4-pyridone)(μ-pyrazine)copper(II)(-μ-pyrazine)diperchlorate ([Cu(pz)1.5(L)2](ClO4)2 where L = 3-X-4-pyridone and X = Br (1) or Cl (2)), contain copper(II)-based ladders in which both the rung and rail bridges are pyrazine molecules bonded through the x2-y2 orbital of the copper(II) ions. This structural scaffold is proposed to approach the isotropic spin-ladder regime. 1 and 2 crystallize in the monoclinic space group P21/c. Due to the bulk of the 3-X-4-HOpy ligands, the ladders are well isolated in the a-direction (1, 15.6 Å; 2, 15.5 Å). The ladders, which run in the b-direction, are stacked in the c-direction with the separation (1, 7.87 Å; 2, 7.82 Å) between copper(II) ions caused by the bulk of a semi-coordinate perchlorate ion coordinated in the axial position. Computational evaluation of magnetic JAB couplings between Cu-moieties of 2 supports the experimentally proposed magnetic topology and agrees with an isolated isotropic spin-ladder (Jrail = -4.04 cm-1 (-5.77 K) and Jrung = -3.89 cm-1 (-5.56 K)). These complexes introduce a convenient scaffold for synthesizing isotropic spin-ladders with modest superexchange interactions, the strength of which may be tuned by variations in L. The magnetic susceptibility down to 1.8 K, for both compounds, is well described by the strong-rung ladder model giving nearly isotropic exchange with Jrung ≈ Jrail ≈ -5.5 K (1) and -5.9 K (2) using the Hamiltonian. Theoretical simulations of the magnetic response of 2 using the isotropic ladder model are in excellent agreement with experiment. The measured magnetization to 5 T indicates a quantum-dominated magnetic spectrum. Again, calculated lower and saturation (4.3 and 24 T, respectively) critical fields for 2 are consistent with experimental measurements, and magnetization data at very low temperatures indeed suggest the presence of quantum effects. Further, the computational study of short- and long-range spin ordering indicates that a 2D-to-3D crossover might be feasible at lower temperatures. Analysis of the Boltzmann population corroborates the presence of accessible triplet states above the singlet ground state enabling the aforementioned 2D-to-3D crossover.
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Affiliation(s)
- Jeffrey C Monroe
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, MA 01610, USA.
| | - M Angels Carvajal
- Dept. Ciència de Materials i Química Física, & IQCTUB, Universitat de Barcelona, Martí i Franquès 1, Barcelona, E-08028, Spain
| | - Christopher P Landee
- Department of Physics, Clark University 950 Main Street, Worcester, MA 01610, USA
| | - Mercè Deumal
- Dept. Ciència de Materials i Química Física, & IQCTUB, Universitat de Barcelona, Martí i Franquès 1, Barcelona, E-08028, Spain
| | - Mark M Turnbull
- Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, MA 01610, USA.
| | - Jan L Wikaira
- Department of Chemistry, University of Canterbury, 20 Kirkwood Ave, Upper Riccarton, Christchurch 8041, New Zealand
| | - Louise N Dawe
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada
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Zhu L, Zhang Z, Jiang X, Yu L, Li X. The syntheses, efficient electromagnetic wave absorption and antibacterial activity properties of novel 3D Ln-MOFs based on maleic hydrazide. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.127826] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Chalmers JE, Srivastava AK, Dixey RJC, Sivakumaran K, Saines PJ. Low dimensional and frustrated antiferromagnetic interactions in transition metal chloride complexes with simple amine ligands. CrystEngComm 2019. [DOI: 10.1039/c8ce01901k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New transition metal chloride complexes with hydrazinium and methylhydroxylamine ligands are reported featuring low dimensional and frustrated magnetic interactions.
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Affiliation(s)
- James E. Chalmers
- School of Physical Science, Ingram Building
- University of Kent
- Canterbury
- UK
| | | | | | | | - Paul J. Saines
- School of Physical Science, Ingram Building
- University of Kent
- Canterbury
- UK
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