Extended coordination frameworks incorporating heterobimetallic squares.

The molecular structure of aluminium and iron(III) complexes with 3-phenyl and 3-(4-pyridyl) (HL) substituted acetylacetonate ligands is appreciably distorted. For AlL3 and FeL3 this shows that the orientation of the side pyridyl-N donor atoms lone pairs is about 90 and 135 degrees which favours the assembly of heterobimetallic square patterns in Al(Fe)L3 complexes with metal ions. This was employed for the modular construction of semi-regular heterobimetallic networks, in which the pyridyldiketonate ligands bridge pairs of Fe(Al)/Cd(Co) metal ions and support the structure of 1D and 2D coordination polymers. The unprecedented 2D structure of [Cd[AlL3](CH3OH)[NO3]2].2CHCl3 and Cd[AlL3](CH3OH)Br2].2CHCl3 . 2CH3OH is based upon plane tiling by a set of heterobimetallic squares and octagons, while [Cd[FeL3]2(NO3)2].2H2O and [Co[AlL3]2Cl2].4CHCl3 . 2CH3OH are 1D polymers and exist as chains of heterobimetallic squares sharing opposite vertices.