Mono‐ and Dinuclear Ni^II and Co^II Complexes that Feature Chelating Guanidine Ligands: Structural Characteristics and Molecular Magnetism

Abstract

Several new mono-and dinuclear complexes of Co II and Ni II with chelating guanidine ligands were synthesized. The molecular structures for most of the complexes in the crystalline state were derived from single-crystal X-ray diffraction, and some characteristic structural details are discussed. The molecular magnetism was further studied by superconducting

The Flexible Coordination Modes of Guanidine Ligands in Zn Alkyl and Halide Complexes: Chances for Catalysis

“…In the first set of experiments, we used the bis(guanidine) ligand bdmegb [1,2-bis(N,NЈ-dimethyl-N,NЈ-ethyleneguanidino)benzene], see Equation (2), which we already introduced as a ligand previously. [15] The complex [(bdmegb)ZnEt 2 ] (1) can be synthesized directly from bdmegb and ZnEt 2 at room temperature in more than 70 % yield [see Equation (2)]. In the 1 H NMR spectrum, the two ethyl groups show at -0.33 (CH 2 ) and 0.99 (CH 3 ).…”

“…The molecular structure as determined from X-ray diffraction is visualized in Figure 1. The two imino N atoms of the guanidino groups form coordinative bonds to the metal ion [with Zn-N bond lengths of 222.88 (18) and 220.57 (15) pm]. The C=N double bond lengths slightly increase (to ca.…”

“…The preparation of bdmegb is detailed in previous work. [15] NMR spectra were measured on a Bruker Avance III 600 spectrometer at a temperature of 23°C, or a Bruker Avance DPX 200, and referenced to known standards [NH 3 (liq.) for 15 N shifts].…”

“…[15] NMR spectra were measured on a Bruker Avance III 600 spectrometer at a temperature of 23°C, or a Bruker Avance DPX 200, and referenced to known standards [NH 3 (liq.) for 15 N shifts]. Elemental analyses were carried out at the Microanalytical Laboratory of the University of Heidelberg.…”

“…C 10 15 N NMR spectroscopic data were recorded with the ligand 15 N 2 -tmua. 15 X-ray Crystallographic Study: Suitable crystals were taken directly out of the mother liquor, immersed in perfluorinated polyether oil, and fixed on top of a glass capillary. Measurements were made on a Nonius-Kappa CCD diffractometer with low-temperature unit using graphite-monochromated Mo-K α radiation.…”