A novel class of oligomeric and polymeric d10metal complexes of asymmetrical N-heterocyclic ligand with strong π-stacking and hydrogen bonding: syntheses, structures, and photoluminescenceElectronic supplementary information (ESI) available: Selected bond lengths and bond angles for compounds 1–5, the shortest DA distances and angles for 1–5, the drawings of the ππ stacking and hydrogen-bonding interactions, and crystallographic data in CIF format. CCDC reference numbers 773660–773663for 1–4. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c1ce05890h

A novel asymmetric N-heterocyclic ligand, 1·H2O [1= (E)-1-methyl-4-nitro-N′-(pyridin-2-ylmethylene)-1H-pyrrole-2-carbohydrazide], was generated by a facile route, and some closed shell metal complexes of the ligand were also synthesized. These complexes include [Zn(1)Cl2] (2), [Cd(1)(μ-Cl)2]n(3), [Hg(1)Cl2] (4) and [K(μ-1)(μ-NO3)]n(5), which were characterized by X-ray crystallography, IR and 1H-NMR spectroscopy, and elemental analyses. The structural studies indicate that ligand 1, with its different conformations and new coordination modes, is an important building block for designing and constructing supramolecular structures viaππ stacking, hydrogen bonding, ClCl and d10–d10interactions. These interactions not only reinforce the stability of structures, but also correlate with the physical properties of complexes. The UV and fluorescence spectral properties were investigated in solution. The titration experiments by d10metal ions imply that ligand 1forms stable complexes at a 1 : 1 ratio and exhibits enhanced fluorescence. Moreover, compared with the solution fluorescence spectra, the solid-state spectra show more significant red-shifts, suggesting that complexes 2–4have possible applications as light emission materials. [ABSTRACT FROM AUTHOR]