Benz(2-heteroaryl)cyanoximes and their Tl(i) complexes: new room temperature blue emitters
作者:Olesya T. Ilkun、Stephen J. Archibald、Charles L. Barnes、Nikolay Gerasimchuk、Richard Biagioni、Svitlana Silchenko、Olga A. Gerasimchuk、Victor N. Nemykin
DOI:10.1039/b803846e
日期:——
A series of five 2-heteroarylcyanoximes such as: α-oximino-(2-benzimidazolyl)acetonitrile (HBIHCO), α-oximino-(N-methy-l-2-benzimidazolyl)acetonitrile (HBIMCO), α-oximino-(2-benzoxazolyl)acetonitrile (HBOCO), α-oximino-(2-benzothiazolyl)acetonitrile (HBTCO) and α-oximino-(2-quinolyl)acetonitrile (HQCO) and their monovalent thallium(I) complexes were synthesized and characterized using spectroscopic methods (1H, 13C NMR, IR, UV-visible, mass-spectrometry) and X-ray analysis. The HBIMCO (as monohydrate) adopts planar trans-anti configuration in the solid state. The crystal structure of “HBOCO” revealed the presence of nitroso anion a, BOCO−, and protonated oxime cation b, H2BOCO+, that form a H-bonded dimer in the unit cell. Both molecules adopt planar structures, but different configurations: cis-anti in the molecule a, and trans-anti for b. This is the first reported case of a zwitterionic pair in oximes and the coexistence of the two geometrical cis/trans isomers in the same crystal. All 2-heteroarylcyanoximes form yellow anions upon deprotonation, which exhibit significant negative solvatochromism in solution. Heterogeneous reactions between hot aqueous solutions of Tl2CO3 and solid protonated 2-heteroarylcyanoximes HL afford yellow TlL. The crystal structure of Tl(BTCO) shows the formation of centrosymmetrical dimers, which connect with each other to form a double-stranded one-dimensional coordination polymer. The oxygen atom of the oxime group acts as a bridge between the three different Tl(I) centers. The anion is non-planar and adopts a trans-anti configuration in the complex. The polymeric motif in the complex represents a ladder-type structure. Staggered π–π interactions between benzothiazolyl groups provide additional stabilization of the structure. Both organic ligands and their Tl(I) complexes exhibit strong room temperature blue emission in the solid state.
合成了一系列五种2-杂芳腈氧肟酸,包括:α-氧肟基-(2-苯并咪唑基)乙腈(HBIHCO)、α-氧肟基-(N-甲基-2-苯并咪唑基)乙腈(HBIMCO)、α-氧肟基-(2-苯并噻唑基)乙腈(HBTCO)和α-氧肟基-(2-喹啉基)乙腈(HQCO)以及它们的单价铊(I) комплексы。采用光谱方法(1H、13C NMR、红外、紫外可见、质谱)和X射线分析对其进行了表征。HBIMCO(作为单水合物)在固态中采用平面反式反式构型。“HBOCO”的晶体结构揭示了存在亚硝基阴离子a(BOCO−)和质子化的氧肟阳离子b(H2BOCO+),它们在单元胞中形成氢键二聚体。这两种分子均采用平面结构,但配置不同:分子a为顺反构型,而b为反式反式构型。这是首次报告在氧肟中发现了两亲离子对,并且同一晶体中共存的两种几何顺/反异构体。所有2-杂芳腈氧肟酸在去质子化后形成黄色阴离子,在溶液中表现出显著的负溶剂色变效应。在Tl2CO3的热水溶液与固态质子化2-杂芳腈氧肟酸HL之间发生的非均相反应生成黄色的TlL。Tl(BTCO)的晶体结构显示形成了中心对称的二聚体,这些二聚体相互连接形成双链一维配位聚合物。氧肟基团的氧原子在三个不同的铊(I)中心之间起桥接作用。该阴离子在复合物中是非平面的,并采用反式反式构型。复杂中的聚合物结构呈现梯子型结构。苯并噻唑基之间错叠的π–π相互作用为结构提供了额外的稳定性。无论是有机配体还是它们的Tl(I)复合物在固态下均表现出强烈的室温蓝色发光。