| Abstract |
Iminopyrrolyl complexes of sodium were prepared from the reaction of 2-arylformiminopyrrole ligand precursors (aryl = C6H5 (I); 2,6-Me2C6H3 (II); 2,4,6- Me3C6H2 (III); 2,6-(Pr2C6H3)-Pr-i (IV)) with one equivalent of sodium hydride. The resulting corresponding compounds 1-4, [\Na(mu(2):kappa N-2,N -iminopyrrolyl)\(2n)(OEt2)(2x)] (n >= 1; x = 0 or 1), were obtained in moderate to high yields and were characterised by NMR spectroscopy, high resolution mass spectrometry and X-ray diffraction, when suitable crystals were obtained. The X-ray structure of compound 1 (n >> 1; x = 0) reveals the formation of a coordination polymer with repeating units consisting of dimers that contain two iminopyrrolyl ligands chelating two sodium atoms, where both pyrrolyl rings exhibit bridging sigma + sigma coordination to the Na atoms within the dimer; the self-assembling of the polymer is established by additional pi-bonds (eta(5)-coordination) of each of the pyrrolyl rings to the sodium atoms of the adjacent dimer units. Conversely, the structure of complex D-IV (n = x = 1) shows it as one of such dimers capped by two diethyl ether molecules, each coordinated to the sodium atoms (n = 2; x = 1). DFT calculations indicate that the differences between the structures of 1-4 arise from the increasing bulkiness imposed by the corresponding substituents of the iminic aryl groups. |
