title: Design and synthesis of Tröger's base ditopic receptors: host-guest interactions, a combined theoretical and experimental study.
abstract: Two flexible Tröger's base ditopic receptors C4TB and C5TB incorporating monoaza crown ether were designed and synthesized for bisammonium ion complexation. A comprehensive study of host-guest interactions was established by (1)H NMR spectroscopy and DFT calculations. Bisammonium chloride (A1) with a shorter alkyl chain spacer showed the highest affinity for the receptors. M06-2X/cc-pVTZ calculations including the solvent effects on host-guest complexes were employed to explain and rationalize the experimental trends. The short N-H···O or N-H···N hydrogen-bond distances observed in the range of 1.71-1.98 Å indicate the existence of a strong charge assisted hydrogen bonding between the host and the guest. The unusual behaviour (higher binding constant) of A5 in (1)H NMR titration is traced to the conformational folding of the guest.
authors.affiliation: Crop Protection Chemicals Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, India. manjula@iict.res.in.
authors.forename: Manda
authors.initials: M
authors.lastname: Bhaskar Reddy
authors.forename: Myadaraboina
authors.initials: M
authors.lastname: Shailaja
authors.forename: Alla
authors.initials: A
authors.lastname: Manjula
authors.forename: Joseph Richard
authors.initials: JR
authors.lastname: Premkumar
authors.forename: Garikapati Narahari
authors.initials: GN
authors.lastname: Sastry
authors.forename: Katukuri
authors.initials: K
authors.lastname: Sirisha
authors.forename: Akella Venkata Subrahmanya
authors.initials: AV
authors.lastname: Sarma
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry; D060326:Chemistry Techniques, Synthetic; D043844:Crown Ethers / Q000138:chemical synthesis* / Q000737:chemistry*; D015195:Drug Design; D006860:Hydrogen Bonding; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D064751:Ammonium Compounds; D043844:Crown Ethers