Theoretical study on hydrogen bonding interaction of ureas and thioureas with imines

Zheng, Wenrui; Fu, Yao; Shen, Kuang; Liu, Lei; Guo, Qi

doi:10.1016/j.theochem.2007.07.023

Cited by 8 publications

(5 citation statements)

References 28 publications

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“…The same rule was discovered in previous hydrogen bonding research [20,21]. Compared with the monomers, the net charges on hydrogen atoms (proton donors) are increased and charges on oxygen atoms (proton acceptors) are decreased for both complexes.…”

Section: Structuressupporting

confidence: 83%

“…Generally, the substrates of these reactions include imines, carbonyl compounds and nitro-compounds, etc. The hydrogen bonding interaction of ureas and thioureas with imines and carbonyl compounds were investigated in a previous study [20,21]. We are thinking about a problem that if these substrates coexist, taking the aza-Henry reaction as an example, which hydrogen bonding complex is prior to generate?…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen bonding interaction between ureas or thioureas and nitro-compounds

Zheng

Huang

et al. 2010

Res Chem Intermed

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The hydrogen bonding interactions between ureas or thioureas and different nitro-compounds were studied using the MP2 method. After comparing four possible conformations, the most stable one was found, which has the typical hydrogen bonding feature of red-shift effect. Based on it, the substituent effects on both nitro-compounds and (thio) urea were researched. The results indicated that electron-withdrawing groups on ureas or thioureas and electron-donating groups on nitro-compounds can both facilitate the hydrogen bonding formation. The NBO analysis further disclosed the essence of the hydrogen bonding interaction. We also studied the cis-trans isomerization of the complexes of (thio) urea with nitroalkenes, which revealed that, for hydrogen-bonding complexes, it is necessary to take both cis and trans isomers into consideration, especially for nitroalkenes with little steric effect substituents.

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Section: Structuressupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Hydrogen bonding interaction between ureas or thioureas and nitro-compounds

Zheng

Huang

et al. 2010

Res Chem Intermed

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“…The urethane groups can only form relatively weak hydrogen bonding (dissociation energy: 18.4 kJ/mol) with carbonyl groups in either another urethane group or other structures. Both urea and thiourea groups can form relatively strong bifurcated hydrogen bonding (dissociation energy: about 58.5 kJ/mol) − with carbonyl groups. However, a urea group can also bind to another urea group, while there is no hydrogen bonding between two thiourea groups due to the significantly lower electronegativity of sulfur than oxygen …”

Section: Resultsmentioning

confidence: 99%

Photothermal Effect-Triggered Drug Release from Hydrogen Bonding-Enhanced Polymeric Micelles

Ding

Zhu

et al. 2018

Biomacromolecules

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Incorporation of noncovalent interactions into hydrophobic cores of polymeric micelles provides the micelles with enhanced physical stability and drug loading efficiency, however, it also creates obstacles for drug release due to the strong interactions between carriers and drugs. Herein, a series of amphiphilic block copolymers based on poly(ethylene glycol)- b-poly(l-lysine) (mPEG- b-PLL) with similar chemical structures, while different hydrogen bonding donors (urethane, urea, and thiourea groups) are synthesized, and their capacities for codelivery of anticancer drug (e.g., doxorubicin) and photothermal agent (e.g., indocyanine green) are investigated. The resulting hybrid micelles display decreased critical micelle concentrations (CMCs) and enhanced micelle stabilities due to the hydrogen bonding between urea groups in the polymers. Moreover, the strong hydrogen bonds between the urea/thiourea groups and drugs provide the carriers with enhanced drug loading efficiencies, decreased micelle sizes, however, slower drug release profiles as well. When exposed to the near-infrared laser irradiation, destabilization of the hydrogen bonding through photothermal effect triggers fast and controlled drug releases from the micelles, which dramatically promotes the aggregation of the drugs in the nuclei, resulting in an enhanced anticancer activity. These results demonstrate that the hydrogen bonding-enhanced micelles are promising carriers for controllable chemo-photothermal synergistic therapy.

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“…The only prior computational study of complexes between thiourea and an imine considered CR 1 2 NCR 2 O, somewhat different from the imines considered here. The geometries of the dimers were optimized at the B3LYP level, with a much smaller 6-31G* basis set.…”

Section: Resultsmentioning

confidence: 99%

Interactions between Thiourea and Imines. Prelude to Catalysis

Nziko

Scheiner

2015

J. Org. Chem.

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The interaction between thiourea and a series of imines was examined via high-level ab initio calculations. For each imine, there is a set of stable complexes that represent minima on the potential energy surface. One type is characterized by a pair of symmetric NH···N hydrogen bonds (HBs), with both NH groups of thiourea approaching the imine N from above and below its molecular plane. Another geometry category combines a linear NH···N with a CH···S HB. A third, which is less stable, has the S approaching the imine's CH2 group, and a stacking arrangement is present in the fourth. Interaction energies vary from ∼2 kcal/mol to a maximum of 13.5 kcal/mol. The formation of the complex tends to elongate the C-N bond within the imine by as much as 0.004 Å, but there are certain dimers that cause a small contraction of this bond.

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Theoretical study on hydrogen bonding interaction of ureas and thioureas with imines

Cited by 8 publications

References 28 publications

Hydrogen bonding interaction between ureas or thioureas and nitro-compounds

Hydrogen bonding interaction between ureas or thioureas and nitro-compounds

Photothermal Effect-Triggered Drug Release from Hydrogen Bonding-Enhanced Polymeric Micelles

Interactions between Thiourea and Imines. Prelude to Catalysis

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