Synthesis, structural characterisation and magnetic behaviour of three new dinuclear end-to-end thiocyanato bridged copper(II) compounds derived from tridentate amines

Abstract

The compounds [Cu 2(μ-SCN) 2(Et 3dien) 2(ClO 4) 2] ( 1), [Cu 2(μ- SCN) 2(Me 5dien) 2](ClO 4) 2 ( 2) and [Cu 2(μ-SCN) 2(ept) 2(ClO 4) 2] ( 3), where Et 3dien is 1,4,7-triethyldiethylenetriamine, Me 5dien is 1,1,4,7,7-pentamethyldiethylenetriamine and ept is N-(2-aminoethyl)-1,3-propanediamine, were synthesised and characterised. The crystal structures of 1, 2 and 3 were determined by single-crystal X-ray analysis. 1: chemical formula C 22H 50Cl 2Cu 2N 8O 8S 2, M=816.80, monoclinic, space group P2 1/ c, a=12.623(4), b=8.708(3), c=17.150(3) Å. β=110.31(2)°, V=1767.9(9) Å 3, D x=1.534 g cm −3, Z=2, F(000)=852, μ(Mo Kα)=15.25 cm −1, λ(Mo Kα)=0.71069 Å, 293(2) K. 2: chemical formula C 20H 46Cl 2Cu 2N 8O 8S 2, M=788.76, monoclinic, space group C2/ c, a=22.701(3), b=13.826(2), c=14.039(2) Å, β=127.55(2)°, V=3493.4(8) Å 3, D x=1.829 g cm −3, Z=4, F(000)=2056, μ(Mo Kα)=27.30 cm −1, λ(Mo Kα)=0.71069 Å, 293(2) K. 3: chemical formula C 12H 30Cl 2Cu 2N 8O 8S 2, M=676.54, orthorhombic, space group Pbca, a=15.169(2), b=13.842(2), c=12.071(2) Å, V=2534.5(6) Å 3, D x=1.773 g cm −3, Z=4, F(000)=1384, μ(Mo Kα)=21.07 cm −1, λ(Mo Kα)=0.71069 Å, 293(2) K. The magnetic susceptibility data of 1, 2 and 3 recorded from 290 to 4 K show that all three are virtually uncoupled compounds. The polycrystalline powder ESR spectra of 1, 2 and 3 recorded at 4, 77, 180 and 298 K remain unchanged, with g ‖=2.18 and g ⊥=2.06 for 1 and a broad signal at g=2.10 for 2 and 3.