title: Theoretical and spectroscopic analysis of N,N'-diphenylurea and N,N'-dimethyl-N,N'-diphenylurea conformations.
abstract: Structural organization of macromolecules is highly dependent on the conformational propensity of the monomer units. Our goal is to systematically quantify differences in the conformational propensities of aromatic oligourea foldamer units. Specifically, we investigate the conformational propensities of N,N'-diphenylurea and N,N'-dimethyl-N,N'-diphenylurea in different media using a combination of theoretical methods, and infrared and nuclear magnetic resonance spectroscopies. Our results show variation in the conformational behavior upon adding methyl substituents on N,N'-diphenylurea, and varying the environments surrounding the compounds. Our energetic analyses and conformational distributions in the gas phase show predominance of the cis-trans and trans-trans conformations for N,N'-diphenylurea, while cis-cis conformation is favored for N,N'-dimethyl-N,N'-diphenylurea. In solution, our results support the trans-trans conformer as the predominant conformer for N,N'-diphenylurea, whereas the cis-cis and cis-trans forms are favored in N,N'-dimethyl-N,N'-diphenylurea. N,N'-Dimethyl-N,N'-diphenylurea also exhibits a more dynamic conformational behavior in solution, with constant fluctuations between cis-cis and cis-trans conformations. Our detailed quantitative analyses are an important aspect in fine-tuning desired conformations and dynamic properties of this class of oligomers by providing a molecular basis for the behavior at the monomeric level.
authors: Department of Marine Sciences, Texas A&M University at Galveston , 200 Seawolf Parkway, Galveston, Texas 77553, United States.
authors: Jhenny F
authors: JF
authors: Galan
authors: Edward
authors: E
authors: Germany
authors: Amanda
authors: A
authors: Pawlowski
authors: Lynette
authors: L
authors: Strickland
authors: Mary Grace I
authors: MG
authors: Galinato
mesh_terms: D001965:Bromides / Q000737:chemistry; D002224:Carbanilides / Q000737:chemistry*; D019281:Dimerization; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D006860:Hydrogen Bonding; D007783:Lactones; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D017680:Potassium Compounds / Q000737:chemistry; D011789:Quantum Theory; D012399:Rotation; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013055:Spectrophotometry, Infrared
chemical_list: D001965:Bromides; D002224:Carbanilides; D005740:Gases; D007783:Lactones; D017680:Potassium Compounds; D012996:Solutions; D012997:Solvents; C522315:vibralactone; C039004:potassium bromide; D004121:Dimethyl Sulfoxide