New cyano functionalized silanes: aggregation-induced emission enhancement properties and detection of 2,4,6-trinitrotoluene: Novel AIEE compounds of cyano functionalized silanes for TNT detection

Two novel tetrahedral silicon-centered cyano functionalized silanes, namely bis(4-cyanophenylethynyl)dimethylsilane (CN-1) and bis(4-cyanophenylethynyl) diphenylsilane (CN-2), have been synthesized and well characterized. They demonstrated unusual aggregation-induced emission enhancement (AIEE) properties in the H-type aggregation state with nanoparticle aggregate formation. Further study shows that the 4-cyanophenylethynyl unit is the structure base to induce the AIEE phenomenon and the silicon core may enhance the AIEE effect. By single-crystal analysis, the twisted tetrahedral conformation of silicon core and restricted intramolecular motions are speculated as the AIEE mechanism for these unusual H-type aggregates of CN-1 and CN-2. Moreover, both CN-1 and CN-2 show an obvious fluorescent quenching response to 2,4,6-trinitrotoluene (TNT) in THF solution, making them promising candidates in the application of explosive detection. Copyright © 2013 John Wiley & Sons, Ltd.