The stepwise formation of mixed-metal coordination networks using complexes of 3-cyanoacetylacetonate.
The complexes [Cu(L(1))2] 1, [Fe(L(1))3] 3 and [Al(L(1))3] 4 [L(1) = CH(3)C(O)C(CN)C(O)CH(3)] have been prepared for use as metallo-ligands in mixed-metal coordination networks. Surprisingly, the nature of the copper precursor is important in the synthesis of 1, with the reaction between Cu(NO3)2.3H2O, HL(1) and NEt3 giving [Cu6(micro(3)-OMe)4(micro-OMe)2(L(1))6] 2 instead of the anticipated 1, which was obtained with CuCl2.2H2O under the same conditions. Compound 1 reacts with AgNO3 to form [Cu(L(1))2.AgNO3](infinity) 5, the structure of which contains one-dimensional chains in which Ag+ ions bridge between molecules of 1. These chains are cross-linked into ladders by bridging nitrates. The product obtained from the reaction of 3 and AgNO3 is crucially dependent on the solvent used. The reaction in methanol-acetone gives [Fe(L(1))3.AgNO3](infinity) 6, {[Fe2(micro-OMe)2(L(1))4.2AgNO3].CH(3)C(O)CH(3)}(infinity) 7 and [Fe2(micro-OMe)2(L(1))4.AgNO3](infinity) 8. Compounds 6 and 8 both have one-dimensional chain structures, whereas 7 has a two-dimensional layer structure. The reaction in methanol gives 6 and 8 as the major products and, in addition, small quantities of {[AgFe2(micro-OMe)2(L(1))4]OH.0.4H2O](infinity) 9. Compound 9 has a three-dimensional structure based on doubly interpenetrated PtS nets. Compounds 7-9 contain Fe2(micro-OMe)2(L(1))4 dimers, but the coordination properties of the dimers differ, with all the cyanides coordinated in 7 and 9 but one uncoordinated in 8. The orientation of the cyanide groups depends on the relative chirality of the iron centres. A transmetallation reaction occurs between 4 and AgNO3 to give [Ag(L(1))](infinity) 10, which has a two-dimensional layer structure. Compounds 2, 3 and 5-10 have been characterised by X-ray crystallography.
Burrows
Andrew D
AD
Department of Chemistry, University of Bath, Claverton Down, Bath, UKBA2 7AY. a.d.burrows@bath.ac.uk
Cassar
Kevin
K
Mahon
Mary F
MF
Warren
John E
JE