First Crystallographic Evidence of Polarity-Assisted Pseudohalides Controllable Heteroaldazine-Based Coordination Polymers: A New Tributary in Low Level Recognition of Explosive from Real-Day Matrices

Abstract

Polarity-assisting pseudohalide-controlled self-assembly of coordination polymers (CPs) is of immense significance for structural tunability and is quite necessary for exploration of the links between structure and properties. Herein, we have synthesized two polarity-assisting pseudohalide-controlled CPs, CPCd-1 and CPCd-2 ({[(Cd₂(L1)₃(NCS)₄].CHCl₃.CH₃CN}_n and {[Cd(L1)₂(N(CN)₂)₂].CH₃CN}_n) using newly developed heteroaldazine-based ligand, L1 (L1 = 1-(Z-(Z-(quinolin-4-ylmethylene) hydrazono) methyl) naphthalen-2-ol) at room temperature and systematically characterized through single-crystal X-ray diffraction (SC-XRD) methodology. Interestingly, strong and continuous π···π intermolecular interactions influence both CPs to ensure high luminescence properties in the solvent medium and in the solid phase. Further, these luminous CPs have been utilized for discriminating recognition of the lethal explosive 2,4,6-trinitrophenol (TNP). Notably, CPCd-2 shows a lower detection limit (193 ppb) toward TNP detection than CPCd-1 (the detection limit is 401 ppb), which is also confirmed by the theoretical scenario. In addition, the sensing mechanism is established via PET-ICT-π···π interaction pathways. Both CPs have numerous practical applications and have been ascertained as innovative ones in environmental domains. This type of pseudohalide-controlled CPs with quinoline-napthaldehyde heteroaldazine-based moieties is scanty in the literature that can detect TNP entirely from the aqueous phase.