Chowdhury Bijit, Sinha Sanghamitra, Ghosh Pradyut
Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A&2B Raja S. C. Mullick Road, Kolkata, 700032, India.
Chemistry. 2016 Dec 12;22(50):18051-18059. doi: 10.1002/chem.201604049. Epub 2016 Nov 2.
The selective phosphate-sensing property of a bis-heteroleptic Ru complex, 1[PF ] , which has a halogen-bonding iodotriazole unit, is demonstrated and is shown to be superior to its hydrogen-bonding analogue, 2[PF ] . Complex 1[PF ] , exploiting halogen-bonding interactions, shows enhanced phosphate recognition in both acetonitrile and aqueous acetonitrile compared with its hydrogen-bonding analogue, owing to considerable amplification of the Ru -center-based metal-to-ligand charge transfer (MLCT) emission response and luminescence lifetime. Detailed solution-state studies reveal a higher association constant, lower limit of detection, and greater change in lifetime for complex 1 in the presence of phosphates compared with its hydrogen-bonding analogue, complex 2. The H NMR titration study with H PO ascertains that the binding of H PO occurs exclusively through halogen-bonding or hydrogen-bonding interactions in complexes 1[PF ] and 2[PF ] , respectively. Importantly, the single-crystal X-ray structure confirms the first ever report on metal-assisted second-sphere recognition of H PO and H P O with 1 through a solitary C-I⋅⋅⋅anion halogen-bonding interaction.
一种具有卤键碘三唑单元的双异质 Ru 配合物 1[PF]的选择性磷酸盐传感特性得到了证明，并且显示出优于其氢键类似物 2[PF]。配合物 1[PF]利用卤键相互作用，与氢键类似物相比，在乙腈和乙腈水溶液中均表现出增强的磷酸盐识别能力，这归因于基于 Ru 中心的金属到配体电荷转移（MLCT）发射响应和发光寿命的显著放大。详细的溶液态研究表明，与氢键类似物配合物 2 相比，配合物 1 在存在磷酸盐时具有更高的缔合常数、更低的检测限和更大的寿命变化。用 H₃PO₄进行的¹H NMR 滴定研究确定，H₃PO₄在配合物 1[PF]和 2[PF]中的结合分别仅通过卤键或氢键相互作用发生。重要的是，单晶 X 射线结构证实了首次报道的通过孤立的 C-I⋅⋅⋅阴离子卤键相互作用，配合物 1 对 H₃PO₄和 H₂PO₄⁻的金属辅助第二球识别。
