Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi-221005, India.
Dalton Trans. 2018 Nov 22;47(45):16264-16278. doi: 10.1039/c8dt03694b.
Eight novel Tl(i) β-oxodithioester complexes, [TlL]n (1-8), with ligands, L = methyl-3-hydroxy-3-(2-furyl)-2-propenedithioate (L1), methyl-3-hydroxy-3-(2-thienyl)-2-propenedithioate (L2), methyl-3-hydroxy-3-(3-pyridyl)-2-propenedithioate (L3), methyl-3-hydroxy-3-(4-pyridyl)-2-propenedithioate (L4), methyl-3-hydroxy-3-(9-anthracenyl)-2-propenedithioate (L5), methyl-3-hydroxy-3-(4-fluorophenyl)-2-propenedithioate (L6), methyl-3-hydroxy-3-(4-chlorophenyl)-2-propenedithioate (L7) and methyl-3-hydroxy-3-(4-bromophenyl)-2-propenedithioate (L8), were synthesized and thoroughly characterized by elemental analysis, and IR, UV-Vis, 1H and 13C{1H} NMR spectroscopy, and their structures were ascertained by X-ray crystallography. Complexes 1 and 2 crystallized in P21 and P212121 chiral space groups, respectively, and were studied using Circular Dichroism (CD) spectra. Solid state structural analyses revealed that the β-oxodithioester ligands are bonded to Tl(i) ions in (O, S) chelating and chelating-bridging modes, thereby forming different types of 1D and 2D coordination polymeric structures. By considering the metal-assisted bonding interactions, various coordination numbers of 5-8 and 10 are established around the metal centre. Except for 5 and 7a which have TlTl separations at 3.724(1) and 3.767(1), 3.891(1) Å respectively, the remaining complexes have no TlTl distances <4.0 Å. This indicates that the majority of structures contain only weak inter- and intramolecular thallophilic interactions. The structures of 1-8 highlight the role played by variations in substituents in the dithioester unit in the structure and properties of the complexes. The multi-dimensional assembly in these complexes rests on important non-covalent C-Hπ (TlOSC3, chelate), C-HX (X = F, Cl, O, N), C-Hπ, HH and rare TlH-C intermolecular anagostic interactions. The TlH-C anagostic interactions together with C-OTl and C-STl interactions formed 7-, 11- and 12-membered chelate rings about the metal centers. The anagostic interactions in 1, 2 and 7b were assessed by theoretical calculations. All the complexes showed bright green luminescent emissions in solution and solid phases. Time-resolved emission spectra revealed a triexponential decay curve and short mean lifetime for fluorescence behavior.
八种新型 Tl(i) β-氧代二硫代酯配合物，[TlL]n（1-8），配体 L = 甲基-3-羟基-3-（2-呋喃基）-2-丙烯二硫代酸酯（L1）、甲基-3-羟基-3-（2-噻吩基）-2-丙烯二硫代酸酯（L2）、甲基-3-羟基-3-（3-吡啶基）-2-丙烯二硫代酸酯（L3）、甲基-3-羟基-3-（4-吡啶基）-2-丙烯二硫代酸酯（L4）、甲基-3-羟基-3-（9-蒽基）-2-丙烯二硫代酸酯（L5）、甲基-3-羟基-3-（4-氟苯基）-2-丙烯二硫代酸酯（L6）、甲基-3-羟基-3-（4-氯苯基）-2-丙烯二硫代酸酯（L7）和甲基-3-羟基-3-（4-溴苯基）-2-丙烯二硫代酸酯（L8），被合成并通过元素分析、IR、UV-Vis、1H 和 13C{1H}NMR 光谱进行了彻底的表征，并通过 X 射线晶体学确定了它们的结构。配合物 1 和 2 分别在 P21 和 P212121 手性空间群中结晶，并使用圆二色（CD）光谱进行了研究。固态结构分析表明，β-氧代二硫代酯配体以（O，S）螯合和螯合桥接模式与 Tl(i) 离子键合，从而形成不同类型的 1D 和 2D 配位聚合物结构。考虑到金属辅助键合相互作用，在金属中心周围建立了各种配位数为 5-8 和 10 的配位。除了 5 和 7a 具有 3.724(1) 和 3.767(1)Å 的 TlTl 分离外，其余配合物没有 TlTl 距离<4.0Å。这表明大多数结构仅含有较弱的TlTl 间和分子内的键合相互作用。1-8 的结构突出了二硫代酯单元中取代基的变化在配合物的结构和性质中的作用。这些配合物中的多维组装依赖于重要的非共价 C-Hπ（TlOSC3、螯合）、C-HX（X = F、Cl、O、N）、C-Hπ、HH 和罕见的 TlH-C 分子内吸引相互作用。TlH-C 吸引相互作用以及 C-OTl 和 C-STl 相互作用形成了金属中心周围的 7、11 和 12 元螯合环。1、2 和 7b 中的吸引相互作用通过理论计算进行了评估。所有配合物在溶液和固态中均表现出明亮的绿色发光发射。时间分辨发射光谱揭示了三指数衰减曲线和荧光行为的短平均寿命。
