Magnetic Interactions through Imidazolate-Bridges: Synthesis, Spectroscopy, Crystal Structure and Magnetic Properties of μ-Imidazolato-Bridged Copper(II) Complexes

Abstract

The synthesis, characterization and crystal structures of substituted imidazolate bridged binuclear copper(II) complexes, [Cu 2 (dien) 2 (L)](ClO 4 ) 3 , where dien ϭ diethylenetriamine, L ϭ imidazolate (im Ϫ ) (1), 2-methylimidazolate (mim Ϫ ) (2) and benzimidazolate (bim Ϫ ) (3), are reported. The copper(II) ions of 1Ϫ3 posses a square planar coordination environment with dien coordinating as a tridentate ligand and the fourth position being occupied by a nitrogen atom of the bridging µ-imidazolato group. In all three compounds the tendency to form additional long apical bonds at the copper(II) ions to the oxygen atoms of the perchlorate anions is observed. Temperature depended susceptibility data of polycrys- Durch Imidazolat-Brücken vermittelte magnetische Wechselwirkungen: Synthese, Spektroskopie, Kristallstruktur und magnetische Eigenschaften von µ-imidazolato-verbrückten Kupfer(II) KomplexenInhaltsübersicht. Die Synthese, Charakterisierung und Kristallstrukturen von zweikernigen Kupfer(II)-Komplexen mit unterschiedlich substituierten Imidazolat-Brücken, [Cu 2 (dien) 2 (L)]-(ClO 4 ) 3 , mit dien ϭ Diethylentriamin, L ϭ Imidazolat (im Ϫ ) (1), 2-Methylimidazolat (mim Ϫ ) (2) und Benzimidazolat (bim Ϫ ) (3), werden beschrieben. Die Kupfer(II)-Ionen von 1Ϫ3 weisen eine quadratisch-planare Koordination, mit dien als dreizähnigem Liganden und der vierten Koordinationsstelle besetzt durch ein Stickstoffatom des verbrückenden µ-Imidazol-Moleküls. Für alle drei Verbindungen beobachtet man die Tendenz zur Ausbildung zusätz-licher langer axialer Bindungen der Kupfer(II)-Ionen zu Sauerstoffatomen der Perchlorat-Anionen. Die Temperaturabhängigkeit der

catena-Poly[copper(I)-μ-2-(2-pyridyl)-1H-benzimidazolato-κ2N1:N3]

“…The pyridyl rings are positioned to be within van der Waals interaction with it, but their basic nitrogen sites do not interact to form bonds. The Cu-N bonds are relatively short, but compare well with those found in 2 -benzimidazolato complexes of copper(I) (Kolks & Lippard, 1984;Plass et al, 2002).…”

Imidazolate bridged Cu(ii)–Cu(ii) and Cu(ii)–Zn(ii) complexes of a terpyridinophane azamacrocycle: a solution and solid state study

“…In order to study the influence of the value of h on J, Plass et al 30 , respectively) both in the solid state and in solution. It can be expected that the molecular structure of the l-imidazolate dicopper(II) core is somewhat different in solution, due to crystal packing effects in the solid state.…”

Dinuclear Nickel(II) and Copper(II) Complexes of 8‐Quinoline‐1H‐pyrazole‐3‐carboxamide: Crystal Structure, Magnetic Properties, and DFT Calculations

“…Remarkably, we were not able to detect a half-field signal (ΔM S = � 2) which is normally observed for an anti-ferromagnetically coupled system with an S = 0 ground and S = 1 excited state. [30,47,[53][54][55][61][62][63][64][65][66][67][68] In view of the 1.7 % paramagnetic impurity concluded from the magnetic measurements, we assume that the inherently weak and broad spectrum of the dinuclear complex is merged with or even completely covered by the signal of the paramagnetic mononuclear Cu(II) impurity.…”