نتایج جستجو برای: urea bond

تعداد نتایج: 107315  

2008
Sohail Saeed Moazzam Hussain Bhatti Uzma Yunus Peter G. Jones

The title compound, C(17)H(16)N(2)O(3)S, crystallizes in the thio-amide form with an intra-molecular N-H⋯O hydrogen bond across the thio-urea system. Mol-ecules are connected in chains parallel to [10] by hydrogen bonds from the second thio-urea N-H group to the benzoate C=O function.

2010
P. D. Riekert Kotze Andreas Roodt Johan A. Venter Stefanus Otto

The title compound, [RhCl(C(8)H(12))(C(14)H(12)N(2)OS)], is a rhodium(I) derivative with a functionalized thio-urea ligand. Despite the presence of several heteroatoms, the thio-urea ligand coordinates only in a monodentate fashion via the S atom. The geometry of the coordination sphere is approximately square planar about the Rh(I) atom, with two bonds to the π-electrons of the 1,5-cyclo-octa-...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Y L A Rezus H J Bakker

We use polarization-resolved mid-infrared pump-probe spectroscopy to study the effect of urea on the structure and dynamics of water. Surprisingly, we find that, even at high concentrations of urea (8 M), the orientational dynamics of most water molecules are the same as in pure liquid water, showing that urea has a negligible effect on the hydrogen-bond dynamics of these molecules. However, a ...

2008
Chung-Yun Hse Feng Fu Hui Pan

For the development of a cost-effective melamine-modified urea formaldehyde resin (MUF), the study evaluated the effects of reaction pH and melamine content on resin properties and bond performance of the MUF resin adhesive systems. Eight resins, each with three replicates, were prepared in a factorial experiment that included two formulation variables: two reaction pHs (i.e., 4.5 and 8.0) and ...

2009
Gün Binzet Ulrich Flörke Nevzat Külcü Hakan Arslan

In the title compound, C(20)H(15)ClN(2)OS, the bond lengths and angles in the thio-urea group are typical of thio-urea derivatives. The C-N bond lengths in the center of the mol-ecule are shorter than the normal C-N single bond due to the resonance effects in this part of the mol-ecule. The conformation of the title mol-ecule with respect to the thio-carbonyl and carbonyl groups is twisted, as ...

2010
Thomas Pinault Bruno Andrioletti Laurent Bouteiller

Supramolecular polymers are linear chains of low molar mass monomers held together by reversible and directional non-covalent interactions, which can form gels or highly viscous solutions if the self-assembled chains are sufficiently long and rigid. The viscosity of these solutions can be controlled by adding monofunctional compounds, which interact with the chain extremities: chain stoppers. W...

2008
B. M. Yamin S. Yousuf M. S. M. Yusof R. H. Jusoh

In the title compound, C(15)H(15)N(3)OS, the thio-urea group is stabilized by an intra-molecular hydrogen bond between the carbonyl O atom and the thio-amide group. A C-H⋯N intramolecular hydrogen bond is also present. Mol-ecules are linked by inter-molecular N-H⋯O and C-H⋯S hydrogen bonds.

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Lan Hua Ruhong Zhou D Thirumalai B J Berne

The mechanism of denaturation of proteins by urea is explored by using all-atom microseconds molecular dynamics simulations of hen lysozyme generated on BlueGene/L. Accumulation of urea around lysozyme shows that water molecules are expelled from the first hydration shell of the protein. We observe a 2-stage penetration of the protein, with urea penetrating the hydrophobic core before water, fo...

Journal: :جنگل و فرآورده های چوب 0
رباب غفاری کارشناس ارشد صنایع چوب و کاغذ، دانشکده منابع طبیعی، دانشگاه تهران،کرج، ایران کاظم دوست حسینی استاد گروه علوم و صنایع چوب و کاغذ، دانشکدة منابع طبیعی، دانشگاه تهران، کرج، ایران علی عبدالخانی استادیار گروه علوم و صنایع چوب و کاغذ، دانشکدة ‏منابع طبیعی، دانشگاه تهران، کرج، ایران سید احمد میرشکرایی استاد دانشکده علوم، دانشگاه پیام نور تهران، تهران، ایران محمد مهدی فائزی پور استاد گروه علوم و صنایع چوب و کاغذ، دانشکده منابع طبیعی، دانشگاه تهران، کرج، ایران

partial replacement of formaldehyde with furfural in the urea-formaldehyde resin on the formaldehydeemission, physical and mechanical properties of particleboard was investigated. the modulus ofrupture (mor), modulus of elasticity (moe), internal bond (ib), water absorption (wa), thicknessswelling (ts) and formaldehyde emission (fe) of poplar particleboards made with the modifiedresins were mea...

2010
Harrison M. Black Russell G. Baughman

In the title urea-based herbicide, C(9)H(10)BrClN(2)O(2), there exist multiple inter- and intra-molecular inter-actions. Most notably, the intra-molecular hydrogen bond between the urea carbonyl O atom and an aromatic H atom affects the planarity and torsion angles of the mol-ecule by restricting rotations about the Ar-secondary amine N and the secondary amine N and the carbonyl C. The two N at...

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