Spectroscopic, Structural, and Theoretical Studies of Halide Complexes with a Urea-Based Tripodal Receptor

Pramanik, Avijit; Powell, Douglas R.; Wong, Bryan M.; Hossain, Md. Alamgir

doi:10.1021/ic202747q

Cited by 52 publications

(63 citation statements)

References 55 publications

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“…23,24 In general, a higher yield was achieved for urea-based receptor (90 %) than the thiourea-based receptor (73%). Attempts to obtain X-ray quality crystals of free receptors or anion complexes were unsuccessful.…”

Section: Resultsmentioning

confidence: 93%

“…Previously reported urea-based receptors linked with ethylene chains showed stronger binding for SO 4 2− than HSO 4 − , in DMSO- d 6 . 20h,23a Thus, the expansion of the tripodal cavity with propylene chains leads to the change of the selectivity patterns for HSO 4 − and SO 4 2− , showing greater selectivity for HSO 4 − . As compared to ethylene-chain analogues, 20h,23a, 23b the propylene chains in L1 and L2 might result in the higher basicity of the central nitrogen, which could be due to the weaker inductive effect 29 of urea/thiourea groups through the longer propylene chains.…”

Section: Resultsmentioning

confidence: 99%

“…21c Our group has recently reported a p -cyanophenyl tripodal urea for sulfate forming a seven coordinate sulfate complex. 23a Further work on this receptor for halides has demonstrated the binding trend in the order of fluoride > chloride > bromide > iodide in solution. 23b Ghosh et al has recently reported that the thiourea analogue p -cyanophenyl tripodal receptor is capable of forming a 1:1 complex with fluoride and 2:1 complex with sulfate, showing moderate extraction efficiencies for fluoride and sulfate from aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and anion binding studies of tris(3-aminopropyl)amine-based tripodal urea and thiourea receptors: proton transfer-induced selectivity for hydrogen sulfate over sulfate

et al. 2015

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Tris(3-aminopropyl)amine-based tripodal urea and thiourea receptors, tris([(4-cyanophenyl)amino]propyl)urea (L1) and tris([(4-cyanophenyl)amino]propyl)thiourea (L2), have been synthesized and their anion binding properties have been investigated for halides and oxoanions. As investigated by 1H NMR titrations, each receptor binds an anion with a 1:1 stoichiometry via hydrogen-bonding interactions (NH⋯anion), showing the binding trend in the order of F− > H2PO4− > HCO3− > HSO4− > CH3COO− > SO42− > Cl− > Br− > I in DMSO-d6. The interactions of the receptors were further studied by 2D NOESY, showing the loss of NOESY contacts of two NH resonances for the complexes of F−, H2PO4−, HCO3−, HSO4− or CH3COO− due to the strong NH⋯anion interactions. The observed higher binding affinity for HSO4− than SO42− is attributed to the proton transfer from HSO4− to the central nitrogen of L1 or L2 which was also supported by the DFT calculations, leading to the secondary acid-base interactions. The thiourea receptor L2 has a general trend to show a higher affinity for an anion as compared to the urea receptor L1 for the corresponding anion in DMSO-d6. In addition, the compound L2 has been exploited for its extraction properties for fluoride in water using a liquid-liquid extraction technique, and the results indicate that the receptor effectively extracts fluoride from water showing ca. 99% efficiency (based on L2).

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis and anion binding studies of tris(3-aminopropyl)amine-based tripodal urea and thiourea receptors: proton transfer-induced selectivity for hydrogen sulfate over sulfate

et al. 2015

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“…The presence of three p -nitro groups as electron withdrawing substituents enhances the acidity of the attached NH groups, thereby increasing the overall activity of the ligand. This hypothesis was supported by a calculation of the electrostatic potential surfaces of a related compound at the M06-2X/6-31G(d,p) level of theory, showing the most positive potential on the NH groups [21]. In addition, the conformational flexibility with six H-donor groups may allow the ligand to interact with active sites of a cell.…”

Section: Introductionmentioning

confidence: 90%

A Synthetic Thiourea-Based Tripodal Receptor that Impairs the Function of Human First Trimester Cytotrophoblast Cells

Horvat

Khansari

Pramanik

et al. 2014

IJERPH

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A synthetic tripodal-based thiourea receptor (PNTTU) was used to explore the receptor/ligand binding affinity using CTB cells. The human extravillous CTB cells (Sw.71) used in this study were derived from first trimester chorionic villus tissue. The cell proliferation, migration and angiogenic factors were evaluated in PNTTU-treated CTB cells. The PNTTU inhibited the CTBs proliferation and migration. The soluble fms-like tyrosine kinase-1 (sFlt-1) secretion was increased while vascular endothelial growth factor (VEGF) was decreased in the culture media of CTB cells treated with ≥1 nM PNTTU. The angiotensin II receptor type 2 (AT2) expression was significantly upregulated in ≥1 nM PNTTU-treated CTB cells in compared to basal; however, the angiotensin II receptor, type 1 (AT1) and vascular endothelial growth factor receptor 1 (VEGFR-1) expression was downregulated. The anti-proliferative and anti-angiogenic effect of this compound on CTB cells are similar to the effect of CTSs. The receptor/ligand affinity of PNTTU on CTBs provides us the clue to design a potent inhibitor to prevent the CTS-induced impairment of CTB cells.

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“…Among the various anions, halides play an important role in environments and life [5]. Interactions between halides and synthetic receptors have been broadly investigated both experimentally and theoretically [2,[6][7][8][9][10][11][12]. Studies indicate that these interactions are mainly attributed to hydrogen bonding and electrostatic attractions.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Studies on Hydrogen Bonds in Anions Encapsulated by an Azamacrocyclic Receptor

Wang

Hossain

et al. 2016

Crystals

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Hydrogen bonds in two halides encapsulated by an azamacrocyclic receptor were studied in detail by the density functional theory (DFT) approaches at B3LYP/6-311++G(d,p) and M06-2X/6-311++G(d,p) levels. The atoms in molecules (AIM) theory and the electron density difference maps were applied for characterizing the hydrogen bond patterns. The results suggest that the fluoride complex has a unique binding pattern which shows a hydrogen bond augmented with ionic bond characteristics.

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Spectroscopic, Structural, and Theoretical Studies of Halide Complexes with a Urea-Based Tripodal Receptor

Cited by 52 publications

References 55 publications

Synthesis and anion binding studies of tris(3-aminopropyl)amine-based tripodal urea and thiourea receptors: proton transfer-induced selectivity for hydrogen sulfate over sulfate

Synthesis and anion binding studies of tris(3-aminopropyl)amine-based tripodal urea and thiourea receptors: proton transfer-induced selectivity for hydrogen sulfate over sulfate

A Synthetic Thiourea-Based Tripodal Receptor that Impairs the Function of Human First Trimester Cytotrophoblast Cells

Theoretical Studies on Hydrogen Bonds in Anions Encapsulated by an Azamacrocyclic Receptor

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