Abstract

New tin(IV) complexes based on various pyrocatechols containing tert-butyl and tert-octyl substituents in the aromatic ring are synthesized and structurally characterized. Reduction of spatially hindered o-quinones with tin amalgam in tetrahydrofuran allows the preparation of compounds with the trans-position of catecholate ligands in the metal coordination sphere. In the further reaction of synthesized tin(IV) biscatecholates with N-donor ligands (pyridine (Py), α,α′-dipyridyl (dipy), 1,10-phenanthroline (phen), pyrazino-[2,3-f][1-10]-phenanthroline (DPQ), dipyrido-[3,2-a:2′3′-c]-phenazine (DPPZ)) the respective six-coordinated complexes are obtained. The introduction of bidentate ligands naturally results in the cis-position of dioxolene ligands in the tin coordination sphere. The possibility of intramolecular ligand–ligand charge transfer (LL′CT) between catecholate and diimine moieties in the synthesized octahedral metal derivatives is shown by electronic absorption spectroscopy. The effect of substituents in catecholate ligands and acceptor properties of diimines on the shift of a long-wave absorption band is determined. The electronic transition corresponding to LL′CT is revealed to undergo a bathochromic shift in the electronic absorption spectrum with a decrease in the polarity of the solvent used.

中文翻译：

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基于二亚胺和 3,5-二叔烷基取代的邻苯二酚的锡 (IV) 配合物

摘要

合成了基于芳香环中含有叔丁基和叔辛基取代基的各种邻苯二酚的新型锡(IV)配合物并进行了结构表征。在四氢呋喃中用锡汞齐还原空间位阻邻醌可以制备在金属配位层中具有儿茶酚配体反位的化合物。合成的二儿茶酚锡 (IV) 与 N-供体配体（吡啶 (Py)、α,α'-联吡啶 (dipy)、1,10-菲咯啉 (phen)、吡嗪基-[2,3- f ]的进一步反应得到[1-10]-菲咯啉(DPQ)、二吡啶并-[3,2- a :2'3'- c ]-吩嗪(DPPZ))各自的六配位络合物。双齿配体的引入自然导致二氧杂环戊烯配体在锡配位球中处于顺式位置。电子吸收光谱显示了合成的八面体金属衍生物中儿茶酚和二亚胺部分之间分子内配体-配体电荷转移（LL'CT）的可能性。确定了儿茶酚酸酯配体中的取代基和二亚胺的受体性质对长波吸收带移动的影响。随着所用溶剂极性的降低，对应于 LL'CT 的电子跃迁在电子吸收光谱中发生红移。