Magnetic concentration and polymorphism in di-n-octyl-, di-n-decyl-, and di-n-dodecylphosphinates of copper(II)

Abstract

. Can. J. Chem. 63, I1 l l (1985). Phosphinates of copper(l1) of the type C U ( R~P O~)~ where R is n-octyl, n-decyl, and n-dodecyl have been synthesized and characterized by differential scanning calorimetry, vibrational and electronic spectroscopy, and variable temperature (300 to 4.2 K) magnetic susceptibility studies. Each of these compounds was obtained in distinct a and P structural forms. All materials appear to have the double phosphinate bridged extended chain structure and the magnetic data have been successfully analyzed according to the isotropic Heisenberg model for linear chains. The a forms exhibit antiferromagnetic behaviour with J values of -25, -29, and -29 cm-' for the octyl, decyl, and dodecyl derivatives respectively. The P forms are ferromagnetic and have corresponding J values of 1.8, 2

Metal pyrazolate polymers. Part 1. Synthesis, structure, and magnetic properties of the [Cu(pz)2]x polymer

“…Computer fits of the experimental data to the model were obtained as described previously (3) fitting function, F (defined in ref. 3), for this fit was 0.0280. The quality of fit is very good and, as expected, the amount of paramagnetic compound required to account for the increase in susceptibility at the lower temperatures is very small.…”

“…In the case of the phosphinates, however, the compression of the Cu04 chromophores is greater, the 0-P-0 bridging system involves three bridge atoms rather than two, and while the T-system of the 0-P-0 is considered to contribute to the superexchange mechanism of coupling between the metal centres, it is probably considerably less effective for this purpose than is the T-system of the pz bridge. Accordingly the strongest antiferromagnetic exchange observed previously is in the a-forms of copper(I1) n-decyl-and n-dodecylphosphinate where I J I values of 29 cm-' have been reported (3). The neutral pyrazine (1,4-diazine, C4H4N2) ligand is also known to bridge copper centres and form linear chain polymers (15)(16)(17).…”

Antiferromagnetism and metamagnetism in 1,4-diazine and pyridine complexes of nickel(II)

“…Differential scanning calorimetry (DSC) studies in the 35-450°C temperature range were made using equipment and procedures previously described (22). For the current studies the measuring cell atmosphere was nitrogen gas at a flow rate of 50 mL min-I.…”

Polynuclear pyrazolate complexes of copper. Crystal and molecular structures of [Cu(tmpz)]3, [Cu(3-CO2dmpz)(tmpzH)]2Cu, and [Cu(4-Br-3-CO2mepz)(4-Br-dmpzH)2]2 (where mepz = methylpyrazolate, dmpz = dimethylpyrazolate, and tmpz = trimethylpyrazolate) and magnetic susceptibility studies on the dinuclear complex

“…Differential scanning calorimetry (DSC) measurements were made with a Mettler DSC 20 standard cell and TClO TA processor as described previously (8). Infrared spectra (450-4000 cm-I) were obtained using a Perkin-Elmer model 598 spectrophotometer.…”