π-π stacking, spin density and magnetic coupling strength.

The π-π stacking interaction, one of the main intermolecular forces, sometimes leads to amazing magnetic properties. Although the concept has been raised that spin density is one of the main factors that contribute to the magnetic coupling strength in intermolecular magnetic coupling systems, it has not been confirmed either experimentally or theoretically to date. Herein we present a study on the magnetostructural data of seven unpublished Cu(II) complexes and ten reported radicals.

Bis(2-chloro-1,10-phenanthroline-κN,N')(thio-cyanato-κN)zinc (2-chloro-1,10-phenanthroline-κN,N')tris-(thio-cyanato-κN)zincate.

The asymmetric unit of the title compound, [Zn(NCS)(C(12)H(7)ClN(2))(2)][Zn(NCS)(3)(C(12)H(7)ClN(2))], contains two cations and two anions. In the cations, the Zn(II) ions have distorted trigonal-bipyramidal environments formed by four N atoms from two 2-chloro-1,10-phenanthroline (cphen) ligands and one N atom from a thio-cyanate ligand. The Zn(II) atoms in the complex anions also have distorted trigonal-bipyramidal environments, formed by two N atoms from a cphen ligand and three N atoms from three thio-cyanato ligands.

[2,9-Bis(3,5-dimethyl-1H-pyrazol-1-yl-κN)-1,10-phenanthroline-κN,N'](methanol-κO)(nitrito-κO,O')cadmium(II) perchlorate.

In the title complex, [Cd(NO(2))(C(22)H(20)N(6))(CH(3)OH)]ClO(4), the Cd(II) ion is in a distorted penta-gonal-bipyramidal CdN(4)O(3) coordination geometry. The dihedral angles formed between the mean planes of the pyrazole rings and the phenanthroline ring system are 4.37 (19) and 5.

π-π Stacking and ferromagnetic coupling mechanism on a binuclear Cu(II) complex.

The ferromagnetic couplings were observed in an unpublished crystal that consists of binuclear copper(II) complexes, namely, [Cu(2)(μ(1,3)-SCN)(2)(PhenOH)(OCH(3))(2)(HOCH(3))(2)] (PhenOH = 2-hydroxy-1,10-phenanthroline), and in the binuclear complex Cu(ii) ion assumes a distorted octahedral geometry and thiocyanate anion functions as a μ(1,3)-SCN(-) equatorial-axial (EA) bridging ligand. The analysis for the crystal structure indicates that there are three types of magnetic coupling pathways, in which two pathways involve π-π stacking between the adjacent complexes and the third one is the μ(1,3)-SCN(-) bridged pathway. The fitting for the data of the variable-temperature magnetic susceptibilities shows that there is a ferromagnetic coupling between adjacent Cu(II) ions with J = 50.

[2,9-Bis(3,5-dimethyl-1H-pyrazol-1-yl-κN)-1,10-phenanthroline-κN,N']bis-(thio-cyanato-κN)cadmium(II).

In the title complex, [Cd(NCS)(2)(C(22)H(20)N(6))], the Cd(II) ion is in a CdN(6) coordination geometry which is inter-mediate between octa-hedral and trigonal-prismatic. The dihedral angles formed between the mean planes of the pyrazole rings and the phenanthroline system are 15.74 (15) and 16.