Theoretical studies of the copper gyromagnetic factors for three novel Cu²⁺ coordination polymers with bi‐triazole ligand

Abstract

The copper electron paramagnetic resonance gyromagnetic factors are theoretically studied for three novel Cu coordination polymers [Cu(XL)(NO ) ] (1), {[Cu(XL)(4,4'-bpy)(NO ) ]•CH CN} (1a) and {[Cu(XL) ](NO ) •3.5H O} (2) with bi-triazole ligand (XL) = N,N'-bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxdiimide bi(1,2,4-triazole) from the high-order perturbation calculations of the g factors for a rhombically elongated octahedral 3d group. The order (1 ≤ 1a < 2) of g can be illustrated by the dominant second-order perturbation term roughly proportional to the square of the covalency factor N. g (and g ) relies on the combination of the contributions from N, cubic field parameter D , and axial elongation of the copper sites and exhibits the sequence (1 ≤ 2 < 1a). As regards the axiality (g ≈ g ) of g factors, this is because the perpendicular rhombic contribution from the deviations of the bond lengths and bond angles for the planar ligands with respect to an ideal octahedron and that from the discrepancies between the crystal fields of the planar ligands O and N largely cancel each other. The present theoretical studies on the copper electron paramagnetic resonance g factors would be helpful to understand the structures and properties of some promising coordination polymers containing copper with the novel bi-triazole ligand XL.

A comparable study of the optical spectra and EPR parameters for 3d1‐ and 3d9‐doped MgNH4PO4·6H2O

“…In the above formulas, the power-law exponents t n ≈ 3 and 5 for n = 2 and 4. [27][28][29][30] A n (R) are the intrinsic parameters; as for 3d n ions in octahedral clusters, the relationships A 2 (R)/ A 4 (R) ≈ 9 $ 12 have been adopted to study the optical and EPR data of TM ions doped in many crystals [31][32][33][34] ; we take A 2 (R) ≈ 12 A 4 (R) here. Similarly, the tetragonal field parameters in Equation 4 can be obtained from the LS parameters of Cu 2+ center in MPPH (i.e., R jj and R ⊥ ) and superposition model [26] :…”

Microwave‐assisted Synthesis, Crystal Structures, and Thermal Stability of C11H10N2Cu2Br3 and C22H20N4Cu8I10

“…Structural examples include orthogonal nets, cubane‐like tetramers, zigzag chains, and stair step polymers. The central copper(I) cation may exhibit two‐, three‐, four‐, or sixfold coordination forming rhombohedral Cu 2 I 2 units, linear [CuBr 2 ] – entities, ladder‐like [Cu 2 Br 3 ] – [6] edge‐shared or bi‐bridged Cu 2 Br 6 4– , Cu 2 X 6 4– dimers (X = Cl, Br, I), triangular [Cu 3 Br] or CuNX 2 units, tetrahedral Cu 2 X 2 /CuX 4 /Cu 2 X 6 /Cu 4 I 4 clusters, and distorted tetrahedral CuBr 4 2– [13] or octahedral CuX 6 coordination complexes . The great number of Cu coordination environment realized with halogen atoms (X) gives rise to a plethora of coordination polymers such as 1D (CuX) ∞ chains, 0D Cu 8 I 8 “double‐chains”, (CuX) ∞ columnar frameworks, (CuBr) ∞ , (CuI) ∞ layer, or 2D cuprous iodide layer Cu 4 I 5 – …”