resumo
Supramolecular materials are important due to their distinct physical and chemical properties. Here we report the synthesis and structural determination, by single-crystal X-ray diffraction, of five new supramolecular networks, namely {[Fe(bpy)(3)OH][dca center dot 4H(2)O]}(n) (1), {[Fe(bpy)(3)][Zn(dca)(3)](2)}(n) (2), {Zn(bpy)(2)(dca)(2)}(n) (3), {Zn(bpy)(dca)(2)}(n) (4) and {[Zn(bpy)(3)][Fe(dca)(3)](2)}(n) (5), where bpy = bipyridine and dca = dicyanamide. Compound 1 is made up of a [Fe(bpy)(3)OH](+) cation layer and a [dca center dot 4H(2)O](-) anion layer. Water clusters are present in the anionic sheet which link adjacent layers of the supramolecular assembly of compound 1. The anionic layer consists of randomly orientated dca anions and water clusters, while the cationic layer has randomly occupied OH groups. Compounds 2 and 5 have similar molecular connectivity to a previously reported structure, but with a different combination of metal centres. They contain a two-dimensional {[M'(dca)(3)(-)}(n) network which provides perfect hexagonal pockets for [M(bpy)(3)](2+) cations. Compound 3 consists of neutral distorted octahedral monomeric units and these monomeric units are connected through intermolecular hydrogen bonding, forming a 3D network. One of anionic dca ligands in compound 3 is also randomly orientated. Compound 4 possesses a zig-zag 1D chain structure and a 3D framework is generated through weak interactions between aromatic rings of adjacent layers. All five compounds contain both bpy and dca. The crystallization of these compounds depends highly on the experimental conditions. (C) 2013 Elsevier Ltd. All rights reserved.
palavras-chave
TRANSITION-METAL-COMPLEXES; SECONDARY BUILDING UNITS; COORDINATION POLYMERS; WATER SUBSTRUCTURES; MAGNETIC-PROPERTIES; ORGANIC FRAMEWORKS; X-RAY; CRYSTAL; CHEMISTRY; DESIGN
categoria
Chemistry; Crystallography
autores
Mal, D; Sen, R; Brandao, P; Lin, Z
nossos autores
Paula Cristina Ferreira da Silva Brandão
Investigador Auxiliar
Zhi Lin
Investigador Principalagradecimentos
The authors acknowledge the financial support from FCT, POCI2010, FSE and FEDER. D.M (SFRH/BPD/65056/2009) and R.S (SFRH/BPD/71798/2010) wish to thank FCT for post doctoral fellowships.