Canting angle dependence of single-chain magnet behaviour in chirality-introduced antiferromagnetic chains of acetate-bridged manganese(iii) salen-type complexes

An acetate-bridged Mn(iii) salen-type alternating chain exhibits slow relaxation of the magnetization categolized to single-chain magnet behavior. The canting motif of the Jahn–Teller axis on the Mn(iii) center is the key to obtain this behavior.

Crystal structure of fac-bis[bis(pyridin-2-yl)methanamine]iron(II) 1,1,3,3-tetracyano-2-(dicyanomethylidene)propane-1,3-diide, [Fe(dipa)2](tcpd)

In the title compound, [Fe(C11H11N3)2](C10N6), the FeII cation is coordinated by two bis(pyridin-2-yl)methanamine (dipa) ligands and has crystallographic twofold symmetry. There are deviations from ideal octahedral geometry due to the steric requirements of the ligands. The polynitrile 1,1,3,3-tetracyano-2-(dicyanomethylidene)propane-1,3-diide (tcpd2−) dianion is disordered about an inversion center and is not coordinated to the Fe atom. The anion is not planar but has a propeller shape. In the crystal, weak N—H...N interactions between the amine H atoms of the dipa ligands and two nitrile groups of the anion form an alternating chain of cations and anions related by the C-centering of the unit cell.

Aminkomplexe des Goldes, Teil 10: Gold(I)-thiocyanat-Komplexe mit Tetrahydrothiophen, Dimethylsulfid, Ammoniak, Aminen und Azaaromatena

The reaction of (tht)AuCl (tht=tetrahydrothiophene) with KSCN leads to a mixture of gold(I) thiocyanate AuSCN and [(tht)2Au]+ [Au(SCN)2]−1. The compounds were separated and the X-ray structure of 1 confirmed as an alternating chain of anions and cations linked by aurophilic contacts. Either pure AuSCN or the mixture was used to synthesize further derivatives of AuSCN, all of which were investigated by X-ray methods. Most products were of limited stability when removed from their mother liquor. The dimethyl sulfide derivative 2 is molecular, (Me2S)AuSCN; the ammonia derivative 3 is ionic, [(NH3)2Au]+ [Au(SCN)2]−. The reaction with 2,2-bipyridyl leads (presumably by involvement of the solvent or of atmospheric moisture) to [bipy-H]+ [Au(SCN)2]−13. All other products involve amines or azaaromatics as ligands L. The primary amine tert-butylamine forms an ionic product [L2Au]+ (SCN)−4. The secondary amines piperidine and dibenzylamine lead to molecular structures LAuSCN (5 and 6), whereas pyridine-based azaaromatics lead to ionic products [L2Au]+ [Au(SCN)2]− with L=2-, 3- or 4-picoline (7–9), 2,4-, 3,4- or 3,5-lutidine (10–12). The 3,4-lutidine derivative 11 forms two polymorphs that tend to form mixed crystals. The dominant features of the crystal packing for 7–12 are short aurophilic interactions.