Synthesis and magnetostructural properties of two crystalline phases of [CuBr2(sp)] (sp=(−)-sparteine)

Crystal structure, spectroscopy and ferromagnetostructural behavior of the complex [CuII(L)(Cl)(L´)]•H2O (L = 2-aminomethylbenzimidazole, L´= L-isoleucinate)

“…25 000 16 666 12 500 10 000 cm At 300/77 K complex 1 powder sample exhibits axial singlet spectra, 21,34,35 with the magnetic parameters obtained from the simulations of the experimental ESR spectra using ES-PRIT computational program of Jeol. 36 The parameter values are g || = 2.150/2.150, g ⊥ = 2.040/2.040 ( iso g value of 2.100), characteristic of d x 2 -y 2 ground state of unpaired electron and rhombic distortion.…”

Variety of polymorphic forms contrasted with uniform crystal packing in sparteine ML2 complexes: Crystal structure, spectroscopic and magnetic properties of (−)-α-isosparteine and (−)-sparteine complexes with CuBr2

“…Copper halide compounds have been the subject of many structural and magnetic studies [4][5][6][7][8][9][10][11]. Electronic and magnetic properties of such compounds have been analyzed in order to establish relationship with their structural features [6][7][8][9][10][11].…”

“…Electronic and magnetic properties of such compounds have been analyzed in order to establish relationship with their structural features [6][7][8][9][10][11]. Among them there are distorted tetrahedral copper(II) (À)-sparteine complexes.…”

“…Among them there are distorted tetrahedral copper(II) (À)-sparteine complexes. There are reports of weak anti-ferromagnetic behavior characteristic for (À)SpCuBr 2 [8], (À)SpCu(PhCOO)Cl [10] and (À)SpCu(Ph-COO)Br [12] complexes. In view of the antiferromagnetic interactions in the copper(II)-halide systems, hydrogen bonding and short Cu-X ... X-Cu contacts were considered as possible pathways for magnetic exchange [13][14][15][16].…”

“…1) (hereafter a-Sp) complex with CuBr 2 (1) and the fourth polymorphic form of (À)SpCuBr 2 complex (2). The other three forms that have been previously reported in the literature have been designated by us as 2a [6,8], 2b [6] and 2c [8]. Polymorphism among the crystals of (À)-sparteine metal(II) complexes is quite often encountered.…”