Aerial CO₂ Trapped as CO₃^2– Ions in a Dimeric Capsule That Efficiently Extracts Chromate, Sulfate, and Thiosulfate from Water by Anion‐Exchange Metathesis

Abstract

The tris(2-aminoethyl)amine-based (tren-based) 3-cyanophenyl-substituted tripodal urea L1, one of the familiar ureabased anion receptors, has shown encapsulation of CO 3 2ions as the carbonate capsule [(L1) 2 ·(CO 3 )·(TBA) 2 ] (1, TBA = tetrabutylammonium) by the fixation of aerial carbon dioxide from basic dimethyl sulfoxide (DMSO) solution. Single-crystal X-ray structural analysis confirmed the encapsulation of CO 3 2ions in the cavity of a dimeric capsular assembly of L1 (9.62 Å) through the formation of twelve strong N-H···O hydrogen-bonding interactions. The excellent CHCl 3 and CH 2 Cl 2 solubility of 1 has been exploited for the liquid-liquid (L-L) extraction of CrO 4 2-, SO 4 2-, and S 2 O 3 2ions from water by anion-exchange metathesis. The extraction of these anions from water was unambiguously confirmed by 1 H NMR spectroscopy, IR spectroscopy, powder XRD (PXRD), and single-crystal X-ray diffraction analysis. The 1 H NMR spectroscopic analysis of the bulk extracts supports the formation of 2:1 (host-guest) complexes. For the CrO 4 2ion, the 53 Cr NMR spectrum of the bulk extract shows a characteristic[a]

Bis-Heteroleptic Ruthenium(II) Complex of Pendant Urea Functionalized Pyridyl Triazole and Phenathroline for Recognition, Sensing, and Extraction of Oxyanions

“…Our previously published results with complex 2 [PF 6 ] 2 suggested that a Ru II complex of a triazole-pyridine and phenanthroline hybrid ligand can act as an efficient sensor for H 2 PO 4 – and HP 2 O 7 3– via a CH···anion hydrogen bonding interaction . The urea moiety is known as an extractor of anions . In order to introduce dual properties such as anion sensing as well as extraction, we have integrated a 4-fluorophenyl urea functionality in the architecture of complex 2 [PF 6 ] 2 to prepare a new bis-heteroleptic ditopic Ru II complex based receptor, i.e.…”

Mechanistic Insight into Fast and Highly Efficient Organocatalytic Activity of a Tripodal Dimeric Hexaurea Capsular Assembly in Michael Addition Reactions

“…A nearly-three-times-higher diffusion coefficient value of the catalyst in CDCl 3 also refers to the same catalytic species according to the Stokes Einstein equation ( D ∝ 1/η for a molecule in different medium where D is the diffusion coefficient of the species and η is the viscosity coefficient of the medium) as DMSO- d 6 has a nearly-three-times-higher η value as compared to CDCl 3 . As the catalyst is known to form a 1:2 (H/G) complex with CO 3 2– in DMSO solution, similar/complementary values of diffusion coefficients of the catalyst in different medium after the reaction indicated that the capsular assembly remained intact throughout the reaction. As we did not have enough evidence of the free pure capsular assembly, C1 in CDCl 3 , we have taken parameters of free pure C1 in DMSO solvent [where it is proved to exist as a 1:2 (H/G) complex] as an initial reference for the existence of capsular assembly.…”

“…The capsular assembly was prepared by treating the monomer with tetrabutylammonium hydroxide (TBAOH) in DMSO in open atmosphere (Scheme 1). After 1 or 2 days, crystals of carbonate-encapsulated dimeric assembly were obtained on the liquid–air interface (for details, see the Experimental Section & ref (17)).…”

Terminal Substituent Induced Differential Anion Coordination and Self-Assembly: Case Study of Flexible Linear Bis-Urea Receptors

“…Because of the impact on frequent biomedical, industrial, and environmental applications as well as the significant role in living organisms, nonhydrated anion recognition has also been subsequently encouraged . In the recent past, a number of research groups − have studied halide and oxyanion binding by acyclic urea/thiourea receptors derived from various amines to understand the role of functional groups with different hydrogen bonding abilities in anion recognition, in addition to the receptor conformation. , …”