Reactivity of the transition metal complexes containing azo, triazine, and hydrazone ligands

这项工作最初源于我们对制备光响应和热响应金属络合物的研究兴趣。偶氮芳香化合物具有很高的色泽，长期以来一直被用作染料和颜料。研究了1-苯偶氮-2-萘胺与吡啶-2-醛或喹啉-2-醛形成的新型三嗪配体及其与钯(II)的络合物，在π-π^*带的照射下，偶氮基发生光反应，并在顺式和反式构象之间异构化。通过加入甲醇和(^nBu)_4NCL，观察到配位二氢三嗪配体的可逆开环和闭环反应。反应可以用MeO~-和Cl~+离子之间的竞争来理解，然后我们合成了2-肼并吡啶和2-(烷硫基)苯甲醛(R=Me，^-Tbu，4-氯苯基)或2-(二苯基膦)苯甲醛衍生的肼类配体及其金属配合物(M=Pd(II)和Pt(II))。配位的肼配体的NH氢原子很容易被去质子化，并在酸的作用下质子化。用分光光度法跟踪反应，观察等色点。未配位的肼配体及其钯(II)配合物没有发射，而铂(II)配合物在可见光区有很强的发射峰。在酸和碱的作用下，观察到发射峰出现可逆的大筛。

This work initially arose from our research interest in the preparation of photo-and thermal-responsive metal complexes. Azoaromatic compounds are highly colored and have long been used as dyes and pigments. It is well known that the azo group is photoreactive and isomerizes between trans and cis conformers by irradiation of the π-π^* bands.We prepared new triazine ligands derived from 1-phenylazo-2-naphtylamine and pyridine-2-aldehyde or quinoline-2-aldehyde, and their palladium(II) complexes. The reversible ring opening and closure reactions of the coordinating dihydrotriazine ligand were observed by the addition of MeOH and (^nBu)_4NCl. The reaction can be understood in terms of competition between MeO^-and Cl^-ions.We, then, prepared hydrazone ligands derived from 2-hydrazinopyridine and 2-(alkylthio)benzaldehyde (R=Me,^tBu,4-chlorophenyl) or 2-(diphenylphosphino)beozaldehyde, and their metal complexes (M=Pd(II) and Pt(II). The NH hydrogen atoms of the coordinated hydrazone ligands were easily deprotonated, and protonated by the action of an acid. The reaction was followed spectrophotometrically, and the isosbestic points were observed. The uncoordinated hydrazone ligands and their palladium(II) complexes was not emissive, however, the platinum(II) complexes showed strong emission peaks in the visible region. Reversible large sifts of the emission peaks were observed by the action of acids and bases.