Dimeric Complex of Alpha Cyclodextrin with 1,12-Diaminododecane. Comparison with other Alpha Cyclodextrin Dimeric Complexes

The structure of the complex of alpha cyclodextrin (αCD) with 1,12-diaminododecane has been determined at room temperature. The compound crystal- lizes in the monoclinic, space group P21, with α = 14.10(2), b = 16.91(2), c = 24.45(4) Å, β = 97.40(3)° and D c = 1.398 gcm-3 for Z = 2. Refinement based on 5552 observed MoKα reflections with I> 2õI led to a final R = 0.075. The diamine molecules thread through two αCD arranged in a head-to-head fashion thus, forming [3]pseudorotaxanes. The amine nitrogen atoms, protruding from the primary hydroxyl sides of the αCD dimer, hydrogen-bond to primary hydroxyl oxygen atoms of consecutive dimers and prevent stacking of the dimers along channels. A comparison of the structure to other dimeric structures of αCD shows differences with respect to geometry and packing of the dimers.