Gutiérrez, L. Alzuet, G. Borrás, J. Castiñeiras, A. Rodríguez-Fortea, A. Ruiz, E. Copper(II) Complexes with 4-Amino-<i>N</i>-[4,6-dimethyl-2-pyrimidinyl]benzenesulfonamide. Synthesis, Crystal Structure, Magnetic Properties, EPR, and Theoretical Studies of a Novel Mixed μ-Carboxylato, NCN-Bridged Dinuclear Copper Compound New Cu(II) complexes of sulfamethazine (4-amino-<i>N</i>-[4,6-dimethyl-2-pyrimidinyl]benzenesulfonamide, HL) [Cu<sub>2</sub>(CH<sub>3</sub>COO)<sub>2</sub>(L)<sub>2</sub>]·2dmf (<b>1</b>) and {[Cu(L)<sub>2</sub>]·2H<sub>2</sub>O}<sub>∞</sub> (<b>2</b>) were prepared and structurally characterized. Compound <b>1</b> crystallizes in the monoclinic system, space group <i>P</i>2<sub>1</sub>/<i>n</i>, with <i>a </i>= 8.9486(9) Å, <i>b </i>= 15.0956(12) Å, <i>c</i> = 16.542(3) Å, <i>β</i> = 105.584(15)°, and <i>Z </i>= 2. Compound <b>2</b> crystallizes in the monoclinic system, space group <i>P</i>2<sub>1</sub>/<i>c</i>, with <i>a </i>= 13.8097(8) Å, <i>b </i>= 14.5765(4) Å, <i>c</i> = 13.7853(15) Å, <i>β</i> = 96.033(9)°, and <i>Z </i>= 1. In compound <b>1</b> two copper ions are linked by two syn−syn acetates and two nonlinear NCN bridging groups pertaining to the deprotonated sulfamethazine ligands. Each copper center presents a nearly square planar geometry. Magnetic susceptibility data for <b>1</b> show a strong antiferromagnetic coupling with 2<i>J</i> = −216.7 cm<sup>-1</sup>. The EPR spectra at the X- and Q-band frequencies present the signals corresponding to the dinuclear entity, being the zero-field splitting parameter, <i>D </i>= 0.265 cm<sup>-1</sup>. The antiferromagnetic exchange coupling is discussed using DFT calculations on some model compounds with NCN bridging ligands and also on model structures with mixed <i>μ</i>-acetato and NCN bridges. The copper in the polymeric compound <b>2</b> is five coordinate. The CuN<sub>5</sub> chromophore has a highly distorted square pyramidal geometry with small axial N−Cu−N angles of 65.53(14) and 59.90(13)°. In the structure a sulfamethazinate anion binds to one copper through the sulfonamido and pyrimidine N atoms and to an adjacent copper via the amino N atom. Crystal Structure;NCN bridges;copper center;EPR spectra;compound 2;2 J;compound 1;0.265 cm;CH 3 COO;HL;Cu 2;Theoretical Studies;antiferromagnetic exchange;1 show;dimethyl;deprotonated sulfamethazine ligands;Magnetic Properties;dinuclear entity;sulfamethazinate anion;nonlinear NCN;2 crystallizes;pyrimidine N atoms;CuN 5 chromophore;copper ions;DFT calculations;Magnetic susceptibility data;model compounds;model structures;N atom;Compound 1 crystallizes 2001-05-19
    https://acs.figshare.com/articles/journal_contribution/Copper_II_Complexes_with_4-Amino-_i_N_i_-_4_6-dimethyl-2-pyrimidinyl_benzenesulfonamide_Synthesis_Crystal_Structure_Magnetic_Properties_EPR_and_Theoretical_Studies_of_a_Novel_Mixed_-Carboxylato_NCN-Bridged_Dinuclear_Copper_Compound/3600738
10.1021/ic000869i.s001