Dimeric complex of alpha cyclodextrin with 1,12-diaminododecane. Comparison with other alpha cyclodextrin dimeric complexes

The structure of the complex of alpha cyclodextrin (alpha CD) with 1,12-dia minododecane has been determined at room temperature. The compound crystall izes in the monoclinic, space group P2(1), with a = 14.10(2), b = 16.91(2), c = 24.45(4) Angstrom, beta = 97.40(3)degrees and D-c = 1.398 gcm(-3) for Z = 2. Refinement based on 5552 observed MoK alpha reflections with I > 2 s igma I led to a final R = 0.075. The diamine molecules thread through two a lpha CD arranged in a head-to-head fashion thus, forming [3]pseudorotaxanes . The amine nitrogen atoms, protruding from the primary hydroxyl sides of t he alpha UCD dimer, hydrogen-bond to primary hydroxyl oxygen atoms of conse cutive dimers and prevent stacking of the dimers along channels. A comparis on of the structure to other dimeric structures of alpha CD shows differenc es with respect to geometry and packing of the dimers.