Tapes of water hexamer clusters in the interlayer space of a 2D MOF:Structural, spectroscopic and computational insight of the confined water

M. C. BERNINI; E. V. BRUSAU; G.E. NARDA; G. ECHEVERRÍA; A. FANTONI; G. PUNTE; A. P, AYALA

POLYHEDRON

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Florida; Año: 2011

0277-5387

The synthesis, crystal structure of [Er2(C4H4O4)3(H2O)4]·6H2O and, with particular emphasis, the structural details and vibrational behaviour of the highly organized sub-net of water, are reported. X-ray structural analysis reveals that the hybrid framework, which can be classified as belonging to the I0O2 type, acts as a host of an infinite tape of six-membered water rings with distorted chair conformation. The water network extends among the hybrid layers helping the close packing and the stabilization of the structure through H-bond interactions, with further development of the supramolecular tridimensional structure. The self-assembly of the hydration water molecules is conditioned by the hybrid host that enforce them to adopt a less stable conformation when compared with hexagonal ice. The vibrational spectra of partially and completely dehydrated samples, as well as of partially isotopic diluted ones have been obtained and analyzed. Theoretical calculations of the vibrational behaviour of a model consisting in a sequence of water clusters at the B3LYP/6-31G** level, were performed to achieve a reliable assignment of the experimental spectra, thus making the vibrational spectroscopy a useful tool in the structural characterization of water sub-structures confined in crystalline environments.