Supramolecular extended systems based on discrete paddle-wheel shaped metal–adeninate entities

Abstract

The present work deals with the design and construction of supramolecular extended systems built up from paddle-wheel shaped metal–adeninate entities in which the deprotonation of the adenine affords a neutral [Cu2(μ-ade-κN3:κN9)4(H2O)2] (ade: adeninate anion) that would avoid the presence of counterions in the channels of the generated supramolecular architecture as happens for the cationic [Cu2(μ-Hade)4(X)2]2+ (Hade: adenine) entity. This strategy allows us to obtain a new compound of formula 3[Cu2(μ-ade-κN3:κN9)4(H2O)2]·2{(NHEt3)2(SO4)}·10H2O·2CH3OH (1) in which the assembly of the neutral dimeric entities gives rise to an open 3D supramolecular architecture with a 45% of void volume. However, such a great available space allows its interpenetration by a second, although different, network of the same neutral [Cu2(μ-ade-κN3:κN9)4(H2O)2] entities assembled into 1D linear chains. The remaining available space within the channels is occupied by triethylammonium cations, sulphate anions, crystallization water and methanol molecules. The resulting crystal structure has been rationalized in terms of the rigidity of the building block, the predictability and rigidity of the synthons and the arrangement of these synthons around the metal–nucleobase discrete entity. The thermal and magnetic characterization of the compound has been also accomplished.