Solvent-controlled solid-state phase transitions of a heterospin Cu(II) complex with imidazolyl-substituted nitronyl nitroxide.

Spontaneous solvent-controlled solid-state transformations were observed for a series of polymeric chain solvates [Cu(hfac)L]·0.5Solv (Solv = (CH)CO, THF, CHCl, CHBr, CHCl) with 2-(1-propyl-1-imidazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1-imidazole-3-oxide-1-oxyl (L) under ambient conditions. The conversion of powdered polymeric chain [Cu(hfac)L]·0.

Pyridyl-Substituted Nitronyl Nitroxides: Comprehensive Magnetochemical and Quantum Chemical Study.

A series of pyridyl-substituted nitronyl nitroxides was synthesized and structurally characterized. A comprehensive magnetochemical and quantum chemical study of extended raw of the nitroxides with different substituents R in the pyridine fragment was performed. It was shown, that temperature-dependent magnetic properties are determined by the short contacts between nitroxide groups of adjacent molecules as well as between nitroxide group and methyl substituents in the pseudo axial positions of imidazoline fragments.

Microgravity-like Crystallization of Paramagnetic Species in Strong Magnetic Fields.

The crystallization of paramagnetic species in a magnetic field gradient under microgravity-like conditions is an area of interest for both fundamental and applied science. In this paper, a setup for the crystallization of paramagnetic species in the magnetic field up to 7 T generated by a superconducting magnet is described. The research includes calculations of the conditions necessary to compensate for the gravitational force for several types of paramagnetic substances using the magnetic field of superconducting magnets (4.

Ferrocenyl-substituted nitronyl nitroxide in the design of one-dimensional magnets.

By the reaction of M(hfac) (M = Mn(II), Co(II), Cu(II), and Zn(II); hfac is the hexafluoroacetylacetonate anion) and ferrocenyl-substituted nitronyl nitroxide (L), we succeeded in the synthesis of stable heterospin complexes: mononuclear [Zn(hfac)L], trinuclear {[Cu(hfac)]L} and chain polymer [Mn(hfac)L] and [Co(hfac)L]. The specific steric bulkiness of the ferrocenyl substituent leads to the formation of -type coordination polyhedra in the [Mn(hfac)L] and [Co(hfac)L] chains. The introduction of the ferrocene substituent leads to an effective weakening of intermolecular or interchain magnetic exchange coupling.

N-Alkylimidazol-5-yl-substituted Nitronyl Nitroxides and Their Mononuclear Cu(II) Complexes: Synthesis, Structure and Magnetic Properties.

A novel synthetic approach has been employed to synthesize a series of new nitronyl nitroxides: 2-(1-propyl-1H-imidazol-5-yl)- (L ), 2-(1-isopropyl-1H-imidazol-5-yl)- (L ) and 2-(1-butyl-1H-imidazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (L ). The reaction of Cu(hfac) with L in a 1 : 2 ratio yields mononuclear heterospin complexes [Cu(hfac) (L ) ] (L =L , L , L ), which have a similar crystal structure to the "jumping" crystals [Cu(hfac) (L ) ] that exhibit chemomechanical activity. It was shown that an increase in the alkyl substituent R leads to changes in the crystal packing of the molecules and the absence of chemomechanical activity.