Oligoacetylacetones as shapable carbon chains and their transformation to oligoimines for construction of metal-organic architectures

Abstract

Abstract Flexible chain-like molecules can adopt various conformations, but fabrication of complex and higher-order architectures by chain networking or coiling is still a difficult task in organic chemistry. As the degree of freedom increases, the large entropy loss impedes conformation and orientation fixing. Here we report oligo (3,3-dimethylpentane-2,4-dione)s as flexible and shapable carbon chains with many carbonyl groups for chemical modification. Polycarbonylated chains of various lengths are synthesized by terminal-selective silylation and oxidative coupling reactions using silver(I) oxide. We use reactions of 1,3-diketones and 1,4-diketones to reduce the chain length and to induce favourable conformations. When the chains are treated with hydrazine, all the carbonyl groups are converted to imine groups, resulting in the formation of multidentate ligands. Finally, a two-dimensional sheet-like structure and a cylindrical assembly are generated by respectively networking and coiling the carbon chains, with the aid of metal coordination.