Molecular clips form isostructural dimeric aggregates from benzene to water.
We report the synthesis and characterization of eight C-shaped methylene-bridged glycoluril dimers (1-8) bearing hydrogen-bonding amide groups on their aromatic rings. Compounds 1-6 undergo tight dimerization in CDCl3 solution (Ks > 9 x 10(5) M(-1)); binary mixtures of 1-7 form mixtures of homodimers and heterodimers in moderately selective dimerization processes (0.23 < or = Keq < or = 768; 0.253 < or = chiAB < 0.933). The high affinity formation of 1.1-6.6 is due to the commensurate nature of the geometrical constraints imposed by the pi-pi interactions and only two hydrogen bonds. The differential response of the strengths of the pi-pi interactions and H-bonds of 2.2 to changes in solvent polarity--from C6D6 to D2O--results in the formation of a solvent-independent isostructural aggregate that exhibits high affinity dimerization across the full range of solvents.
Wu
Anxin
A
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
Mukhopadhyay
Pritam
P
Chakraborty
Arindam
A
Fettinger
James C
JC
Isaacs
Lyle
L
D001555:Benzene Derivatives / Q000737:chemistry*; D019281:Dimerization; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry; D014867:Water / Q000737:chemistry
D001555:Benzene Derivatives; D014867:Water; D014508:Urea