A hindered urea bond (HUB), recently reported as a new type of dynamic chemical bond, can be facilely constructed by mixing an isocyanate and a hindered amine. Here, we report the use of the HUB in the design of degradable hydrogel materials for applications of stem cell encapsulation and delivery. Polyethyleneglycol (PEG) diamine was end-capped with a HUB and an allyl group in a one-pot synthe...

Urea is ubiquitously used as a protein denaturant. To study the structure and energetics of aqueous urea solutions, we have carried out molecular dynamics simulations for a wide range of urea concentrations and temperatures. The hydrogen bonds between urea and water were found to be significantly weaker than those between water molecules, which drives urea self-aggregation due to the hydrophobi...

In the title compound, C(13)H(12)N(2)S·C(3)H(6)O, the phenyl rings of the thio-urea mol-ecule are in syn and anti positions in relation to the C=S bond. Two mol-ecules are connected by N-H⋯S=C hydrogen bonds into a centrosymmetric dimer. An additional N-H⋯O=C hydrogen bond to the acetone solvent mol-ecule and some weak C-H⋯π inter-actions reinforce the crystal structure.

In the title compound, C12H15FN2O2S, the mol-ecule adopts a cis configuration of the fluoro-benzoyl group with respect to the thiono group about their C-N bond. The dihedral angle between the fluoro-benzoyl group and the thio-urea N2CS fragment is 69.60 (11)°. An intra-molecular N-H⋯O hydrogen bond occurs. In the crystal, mol-ecules form chains along the b-axis direction via O-H⋯S and C-H⋯O hyd...

In the title compound, C(20)H(26)N(2)OS, four non-H atoms of the thio-urea unit are approximately planar (r.m.s. deviation = 0.005 Å); the phenyl and benzene rings are twisted out of this plane by 28.55 (7) and 60.00 (7)°, respectively. An intra-molecular N-H⋯O hydrogen bond occurs. The hy-droxy group is hydrogen bonded to the double-bond S atom of an inversion-related mol-ecule, generating a h...

Ab initio and density functional theory (DFT) calculations on some model systems are presented to assess the extent to which intermolecular hydrogen bonding can affect the planarity of amide groups. Formamide and urea are examined as archetypes of planar and non-planar amides, respectively. DFT optimisations suggest that appropriately disposed hydrogen-bond donor or acceptor molecules can induc...

Ab initio and density functional theory (DFT) calculations on some model systems are presented to assess the extent to which intermolecular hydrogen bonding can affect the planarity of amide groups. Formamide and urea are examined as archetypes of planar and non-planar amides, respectively. DFT optimisations suggest that appropriately disposed hydrogen-bond donor or acceptor molecules can induc...

The title compound, C(25)H(44)N(4)O(5), exhibits a turn with the main chain reversing direction, held together by an intramolecular N-H.O hydrogen bond. In the urea fragment, a notable amide C-N bond between the carboxyl C and the tertiary N atom shows marked single-bond character [1.437 (2) A]. The dihedral angle of the beta-alanyl residue, centrally located in the turn, is gauche [69.2 (2) de...

The activation of human plasminogen in a 25% glycerol medium was carried out with low molar ratios of urokinase, streptokinase, trypsin, and pig heart activator. Starch gel electrophoresis in 8 M urea at pH 3.2 showed that each of the four plasmins possessed the same electrophoretic mobility. Upon reduction with 2-mercaptoethanol in 8 M urea, each plasmin was found to contain two major, electro...

The asymmetric unit of the title compound, C(14)H(8)Cl(4)N(2)OS·0.5H(2)O, contains two independent mol-ecules with different conformations with respect to the aromatic ring planes, and one water mol-ecule. The bond lengths and angles are typical of thio-urea compounds of this class. The mol-ecule exists in the solid state in its thione form with typical thio-urea C-S and C-O bonds lengths, as w...