Synthesen und Strukturen von Bis(4,4′‐t‐butyl‐2,2′‐bipyridin)‐Ruthenium(II)‐Komplexen mit funktionellen Derivaten des Tetramethyl‐bibenzimidazols

• Published in: Zeitschrift für anorganische und allgemeine Chemie (1950) Vol. 633; no. 7; pp. 961 - 970
• Main Authors: Grüßing, André, Rau, Sven, Schebesta, Sebastian, Scholz, Alexander, Görls, Helmar, Walther, Dirk
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag 01.06.2007
• Subjects: Bibenzimidazoles; Bis(4,4′‐t‐butyl)‐2,2′ bipyridine; Crystal structures; Platinum; Ruthenium
• ISSN: 0044-2313; 1521-3749
• DOI: 10.1002/zaac.200700007

Syntheses and Structures of Bis(4,4′‐t‐butyl‐2,2′‐bipyridine) Ruthenium(II) Complexes with functional Derivatives of Tetramethyl‐bibenzimidazole [(tbbpy)2RuCl2] reacts with dinitro‐tetramethylbibenzimidazole (A) in DMF to form the complex [(tbbpy)2Ru(A)](PF6)2 (1a) (tbbpy: bis(4,4′‐t‐butyl)‐2,2′bipyridine). Exchange of the two PF6− anions by a mixture of tetrafluor‐terephthalat/tetrafluor‐terephthalic acid results in the formation of 1b in which an extended hydrogen‐bonded network is formed. According to the 1H NMR spectra and X‐ray analyses of both 1a and 1b, the two nitro groups of the bibenzimidazole ligand are situated at the periphery of the complex in cis position to each other. Reduction of the nitro groups in 1a with SnCl2/HCl results in the corresponding diamino complex 2 which is a useful starting product for further functionalization reactions. Substitution of the two amino groups in 2 by bromide or iodide via Sandmeyer reaction results in the crystalline complexes [(tbbpy)2Ru(C)](PF6)2 and [(tbbpy)2Ru(D)](PF6)2 (C: dibromo‐tetrabibenzimidazole, D: diiodo‐tetrabibenzimidazole). Furthermore, 2 readily reacts with 4‐t‐butyl‐salicylaldehyde or pyridine‐2‐carbaldehyde under formation of the corresponding Schiff base RuII complexes 5 and 6. 1H NMR spectra show that the substituents (NH2, Br, I, azomethines) in 2 ‐ 6 are also situated in peripheral positions, cis to each other. The solid state structure of both 2, and 3, determined by X‐ray analyses confirm this structure. In addition, the X‐ray diffraction analyses of single crystals of the complexes [(tri‐t‐butyl‐terpy)(Cl)Ru(A)] (7) and [(A)PtCl2] (8) display also that the nitro groups in these complexes are in a cis‐arrangement.