Mercurio James M, Knighton Richard C, Cookson James, Beer Paul D
Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA (UK), Fax: (+44) 1865-272690.
Chemistry. 2014 Sep 8;20(37):11740-9. doi: 10.1002/chem.201403317. Epub 2014 Aug 11.
The anion-templated synthesis of three novel halogen-bonding 5-halo-1,2,3-triazolium axle containing [2]rotaxanes is described, and the effects of altering the nature of the halogen-bond donor atom together with the degree of inter-component preorganisation on the anion-recognition properties of the interlocked host investigated. The ability of the bromotriazolium motif to direct the halide-anion-templated assembly of interpenetrated [2]pseudorotaxanes was studied initially; bromide was found to be the most effective template. As a consequence, bromide anion templation was used to synthesise the first bromotriazolium axle containing [2]rotaxane, the anion-binding properties of which, determined by (1) H NMR spectroscopic titration experiments, revealed enhanced bromide and iodide recognition relative to a hydrogen-bonding protic triazolium rotaxane analogue. Two halogen-bonding [2]rotaxanes with bromo- and iodotriazolium motifs integrated into shortened axles designed to increase inter-component preorganisation were also synthesised. Anion (1) H NMR spectroscopic titration experiments demonstrated that these rotaxanes were able to bind halide anions even more strongly, with the iodotriazolium axle integrated rotaxane capable of recognising halides in aqueous solvent media. Importantly, these observations suggest that a halogen-bonding interlocked host binding domain, in combination with increased inter-component preorganisation, are requisite design features for a potent anion receptor.
本文描述了通过阴离子模板法合成三种新型含卤素键的5-卤代-1,2,3-三唑鎓轴[2]轮烷，并研究了改变卤素键供体原子的性质以及组分间预组织程度对互锁主体阴离子识别性能的影响。最初研究了溴代三唑鎓基序引导卤化物阴离子模板组装互穿[2]准轮烷的能力；发现溴离子是最有效的模板。因此，利用溴离子模板法合成了首个含[2]轮烷的溴代三唑鎓轴，通过¹H NMR光谱滴定实验测定其阴离子结合性能，结果表明相对于氢键质子化三唑鎓轮烷类似物，其对溴离子和碘离子的识别能力增强。还合成了两种卤素键[2]轮烷，其中溴代和碘代三唑鎓基序整合到缩短的轴中，旨在增加组分间的预组织。阴离子¹H NMR光谱滴定实验表明，这些轮烷能够更强烈地结合卤化物阴离子，含碘代三唑鎓轴的轮烷能够在水性溶剂介质中识别卤化物。重要的是，这些观察结果表明，卤素键互锁主体结合域与增加的组分间预组织相结合，是高效阴离子受体的必要设计特征。
