Structure and magnetism of catena-poly[copper(II)-μ-dichloro-l-lysine]hemihydrate: Copper chains with monochloride bridges

Santana, Ricardo Costa de; Ferreira, Bruno N.; Sabino, José R.; Carvalho, J. F.; Peña, O.; Calvo, Rafael

doi:10.1016/j.poly.2012.08.045

Cited by 12 publications

(7 citation statements)

References 67 publications

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“…6 Dicyanamide-bridged complexes have a diverse variety of magnetic, 7 ferroelectric 8 and optical properties. 9 In recent years, a large number of reports have focused on the synthesis and magnetic properties of chloride-bridged, [10][11][12][13][14][15][16][17][18][19] azide-bridged [20][21][22][23][24][25] or alkoxy-bridged systems. [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] However, chloride-bridged octahedral-tetrahedral Cu(II) complexes have seldom been reported.…”

Section: Introductionmentioning

confidence: 99%

Assembly of dinuclear copper(ii) secondary building units into polymeric complexes: crystal structures and magnetic properties

2014

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Four Cu(II) complexes, the one-dimensional [Cu(HL 1 ) 2 (CuCl 4 )] n (1), {[Cu 2 (L 1 ) 2 (N(CN) 2 )(CH 3 OH)](ClO 4 )} n (2), dinuclear [Cu 2 (L 2 ) 2 Cl 2 ] (3), and two-dimensional layered [Cu 2 (L 2 ) 2 (N(CN) 2 ) 2 ] n (4) were synthesized by Cu(II) salts (CuCl 2 •2H 2 O or Cu(ClO 4 ) 2 •6H 2 O), alkanol bidentate ligands trans-2-(1-pyrazolyl)cyclohexanol (HL 1 ) or3,5-dimethyl-N-hydroxyethyl-pyrazolyl (HL 2 ) together with sodium dicyanamide. For complex 1, the bridging chlorine atoms of the tetrahedral [CuCl 4 ] 2− moieties are located at the Jahn-Teller axis of the elongated octahedral Cu(II), forming an alternate elongated-octahedral-tetrahedral Cu(II) chain complex.For complexes 2, 3 and 4, the alkyl oxygen atoms of the deprotonated ligands HL 1 and HL 2 bridge two Cu(II) ions, yielding a dinuclear Cu(II) unit [Cu 2 (L x ) 2 ] 2+ (x = 1, 2), and one-or two-dimensional complexes via bridging dicyanamide ligands. Complex 1 shows weak ferromagnetic coupling, whilst complexes 2-4 display strong antiferromagnetic coupling or are even nearly diamagnetic due to the large Cu-O-Cu bond angles.

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Section: Introductionmentioning

confidence: 99%

Assembly of dinuclear copper(ii) secondary building units into polymeric complexes: crystal structures and magnetic properties

2014

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“…In the spectra at room temperature, we clearly see (indicated by arrows) two components. On the basis of the line shape and the magnetic field of the central main peak, and on the basis of the comparison with similar spectra in the literature, the two components were ascribed to different coordination complexes of Cu(II) in an axially elongated octahedral geometry. The notation Cu‐NxOy simply indicates that Cu(II) coordinates x nitrogen atoms and y oxygen atoms belonging to DGL interacting sites or water molecules.…”

Section: Resultsmentioning

confidence: 55%

“…The magnetic parameters extracted from the simulation were then compared with equivalent parameters found in the literature . This allowed us to assign each spectral component to a copper coordination and identify the structure and complexing sites of the DGLs.…”

Section: Methodsmentioning

confidence: 99%

Multi-Technique Characterization of Poly-L-lysine Dendrigrafts-Cu(II) Complexes for Biocatalysis

et al. 2014

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Poly-L-lysine is a biocompatible polymer used for drug or gene delivery, for transport through cellular membranes, and as nanosized magnetic resonance imaging contrast agents. Cu(II)-poly-L-lysine complexes are of particular interest for their role in biocatalysis. In this study, poly-L-lysine dendrigrafts (DGLs) at different generations (G2, G3, and G4) are synthesized and characterized in absence and presence of Cu(II) by means of electron paramagnetic resonance (EPR), UV-Vis, potentiometric titration and circular dichroism (CD). The analysis is performed as a function of the [Cu(II)]/[Lys] (=R) molar ratio, pH and generation by identifying differently flexible complexes in different dendrimer regions. The amine sites in the lateral chains become increasingly involved with the increase of pH. The good agreement and complementarity of the results from the different techniques provide an integrate view of the structural and dynamic properties of Cu(II)-DGL complexes implementing their use as biocatalysts.

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“…The strength of the AFM exchange coupling in spin chains varies over several orders of magnitude, e.g. ∼ 10 −24 J for Cu chains with monochloride bridges [41], ∼ 10 −23 J for pyridine-based Cu chains [42] and ∼ 10 −22 J for molecular wheels Cr 8 Cd [43][44][45]. The latter is about an order of magnitude smaller than the exchange in the bulk Cr 2 O 3 (∼ 10 −21 J) [46].…”

Section: Discussionmentioning

confidence: 99%

Field-induced spin reorientation transitions in antiferromagnetic ring-shaped spin chains

Borysenko¹,

Sheka²,

Faßbender³

et al. 2022

Preprint

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Easy axis antiferromagnets are robust against external magnetic fields of moderate strength. Spin reorientations in strong fields can provide an insight into more subtle properties of antiferromagnetic materials, which are often hidden by their high ground state symmetry. Here, we investigate theoretically effects of curvature in ring-shaped antiferromagnetic achiral anisotropic spin chains in strong magnetic fields. We identify the geometry-governed helimagnetic phase transition above the spin-flop field between vortex and onion states. The curvature-induced Dzyaloshinskii-Moriya interaction results in the spin-flop transition being of first-or second-order depending on the ring curvature. Spatial inhomogeneity of the Néel vector in the spin-flop phase generates weak ferromagnetic response in the plane perpendicular to the applied magnetic field. Our work contributes to the understanding of the physics of curvilinear antiferromagnets in magnetic fields and guides prospective experimental studies of geometrical effects relying on spin-chain-based nanomagnets.

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Structure and magnetism of catena-poly[copper(II)-μ-dichloro-l-lysine]hemihydrate: Copper chains with monochloride bridges

Cited by 12 publications

References 67 publications

Assembly of dinuclear copper(ii) secondary building units into polymeric complexes: crystal structures and magnetic properties

Assembly of dinuclear copper(ii) secondary building units into polymeric complexes: crystal structures and magnetic properties

Multi-Technique Characterization of Poly-L-lysine Dendrigrafts-Cu(II) Complexes for Biocatalysis

Field-induced spin reorientation transitions in antiferromagnetic ring-shaped spin chains

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