ISSN:
1573-1111
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Crystal and molecular structures of (1:1) molecular complexes of N,N′,N″,N″-tetramethyl-2, 11, 20, 29-tetraaza [3.3.3.3] paracyclophane (1) with CHCl3, CH2Cl2, CH3CN and CO2 are reported. The macrocycle has square-box structure, giving hydrophobic cavity surrounded by four benzene rings. The guest molecules are included in the cavity. The uncomplexed1 was found to have a rectangular form, indicating large conformational flexibility of1. In solution,1 is achiral because rapid R⇌S interconversion, but in solid, the macrocyclic conformation is frozen as “R”-conformer or “S”-conformer. The macrocycles with the same chirality are stacked alongb-axis to form chiral molecular columns, “R”-colums or “S”-columns. Complexes of1 crystallize differently depending on the guest molecules. “R”-columns (“S”-columns) packed alonga-axis produce “R”-layers (“S”-layers), which are further packed alongc-axis using “R”-layer to “R”-layer contact (RR) or SS and RS or SR. The crystals of1·CHCl3 are formulated as--RRR--=[R]n (Type I, chiral) and those of1·CH3CN or1·CO2 and1·CH2Cl2 are represented by [RS]n (Type IIA, racemic) and [RRSS]n (Type IIB, racemic), respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00663259
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