Synthesis of Secondary, Tertiary and Quaternary 1,3,5‐Triazapenta‐1,3‐dienes and Their Co
<sup>II</sup>
, Zn
<sup>II</sup>
, Pd
<sup>II</sup>
, Cu
<sup>II</sup>
and BF
<sub>2</sub>
Coordination Compounds
作者:Ina Häger、Roland Fröhlich、Ernst‐Ulrich Würthwein
DOI:10.1002/ejic.200900042
日期:2009.6
AbstractThe secondary and tertiary 1,3,5‐triazapenta‐1,3‐dienes 2 and 3 are easily obtained by the reaction of N‐imidoyl chlorides with amidines or from ethyl N‐imidoylimidoates 5 and primary amines. In a new synthetic pathway the compounds 5 were prepared by the reaction of imidoates in their protonated or free form with N‐imidoyl chlorides. A quaternary 1,3,5‐triazapenta‐1,3‐diene 4a is obtained by the reaction of the imidoate 5b with pyrrolidine. X‐ray diffraction studies of the tertiary 1,3,5‐triazapenta‐1,3‐diene 3c and its protonated form 3c·HCl allow the comparison of different patterns of intermolecular hydrogen bonding in the solid state. Two equivalents of a secondary 1,3,5‐triazapenta‐1,3‐diene 2 were treated at room temperature after deprotonation with potassium tert‐butoxide with CuCl2, Ni(ClO4)2 or with Pd(ac)2 (without deprotonation) to give the corresponding neutral 2:1 chelate complexes (2a)2·Cu, (2a)2·Ni and (2b)2·Pd, respectively. A fluorescent boron complex 2b·BF2 was obtained by reacting 2b with boron trifluoride–diethyl ether. From the tertiary triazapentadiene 3c and CoCl2 or ZnCl2 the six‐membered 1:1 chelate complexes 3c·CoCl2 and 3c·ZnCl2, respectively, were obtained. In these cases a proton shift from the terminal nitrogen atom of the free ligand to the central nitrogen atom of the complex was observed. Two equivalents of 3c reacted at room temperature with Cu(ac)2 or Pd(ac)2 to form the neutral 2:1 chelate complexes (3c)2·Cu and (3c)2·Pd, respectively. A fluorescent 1:1 boron complex 3c·BF2 was obtained from 3c and boron trifluoride–diethyl ether. In all cases the triazapentadienes act as neutral or anionic bidentate ligands to form six‐membered chelates with the metal ion or the boron centre. Most of the complexes were completely characterized, which included X‐ray crystallography.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)