An Old Crystallization Technique as a Fast, Facile, and Adaptable Method for Obtaining Single Crystals of Unstable "LiTCNQF" and New Compounds of TCNQ or TCNQF: Syntheses, Crystal Structures, and Magnetic Properties.

Detailed structural information is essential for understanding the properties of TCNQ and TCNQF compounds (TCNQ = 7,7,8,8-tetracyanoquinodimethane; TCNQF = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane). The ineludible requirement of obtaining crystals of a size and quality sufficient to yield a successful X-ray diffraction analysis has been challenging to satisfy because of the instability of many of these compounds in solution. Crystals of two new complexes of TCNQ, [-M(2)(TCNQ)] [M = Ni (), Zn (); 2ampy = 2-aminomethylpyridine], as well as unstable [Li(TCNQF)(CHCN)]·CHCN (), can be prepared in minutes by a horizontal diffusion technique and can be harvested easily for X-ray structural studies.

-{Er } complex showing field supported slow magnetic relaxation.

The -{Er} complex [ErCl()(OH)(HO)]Cl·HO ( = 9.4; H() = -vanillin) (1) was generated by an method. The isolated Er(iii) complex 1 was characterized by elemental analysis and molecular spectroscopy.

Slow magnetic relaxation in Ni-Ln (Ln = Ce, Gd, Dy) dinuclear complexes.

Three new isomorphous complexes [Ni(o-van-en)LnCl(HO)] [H(o-van-en) = N,N'-ethylene-bis(3-methoxysalicylaldiminate; Ln = Ce (1), Gd (2), Dy (3)] were prepared by a stepwise reaction using mild conditions and were structurally characterised as dinuclear molecules in which Ni and Ln are coordinated by the compartmental Schiff base ligand (o-van-en) and doubly bridged by O atoms. While the nickel(ii) centre is diamagnetic within the NO square-planar coordination of the Schiff base ligand, the lanthanide atoms are octa-coordinated to give an {LnClO} chromophore with a fac-arrangement of the chlorido ligands. AC magnetic measurements revealed that all three complexes, including the nominally isotropic Gd(iii) system, show field induced slow magnetic relaxation with two or three relaxation channels: at T = 1.

Polymorphism of the dinuclear Co-Schiff base complex [Co(o-van-en)]·4CHCN (o-van-en is a salen-type ligand).

Reactions of Co(OH) with the Schiff base bis(2-hydroxy-3-methoxybenzylidene)ethylenediamine, denoted H(o-van-en), under different conditions yielded the previously reported complex aqua[bis(3-methoxy-2-oxidobenzylidene)ethylenediamine]cobalt(II), [Co(CHNO)(HO)], 1, under anaerobic conditions and two polymorphs of [μ-bis(3-methoxy-2-oxidobenzylidene)ethylenediamine]bis{[bis(3-methoxy-2-oxidobenzylidene)ethylenediamine]cobalt(III)} acetonitrile tetrasolvate, [Co(CHNO)]·4CHCN, i.e. monoclinic 2 and triclinic 3, in the presence of air.

Exceptionally slow magnetic relaxation in cobalt(ii) benzoate trihydrate.

Cobalt(ii) benzoate trihydrate prepared by the reaction of CoCO with benzoic acid (HBz) in boiling water followed by crystallization has been structurally characterized as a chain-like system with the formula unit [Co(Bz)(HO)]Bz·HO where the Co(ii) atoms are triply linked by one bridging syn-syn benzoato (Bz) and two aqua ligands; additional benzoate counter ions and solvate water molecules are present in the crystal structure. DC magnetic measurements reveal a sizable exchange coupling of a ferromagnetic nature between the Co(ii) atoms. At T = 5.