Designing neutral coordination networks using inorganic supramolecular synthons: combination of coordination chemistry and C-H···Cl hydrogen bonding

Abstract

Crystal structure determination of two compounds, [(L³)Mn^IICl₂(EtOH)] (1) and [(L⁶)Fe^IIICl₃] (2) [L³ = 2-[3-(2'-pyridyl)pyrazol-1-ylmethyl]pyridine; L⁶ = methyl[2-(2-pyridyl)ethyl](2-pyridylmethyl)amine], the former one reported for the first time, demonstrates that these coordination units can be used effectively as supramolecular synthons in crystal engineering to construct neutral networks. In continuation of our recent contribution on inorganic crystal engineering from the standpoint of metal-ligand coordination chemistry and C-H···Cl₂M^II hydrogen-bonding, in this work we have investigated the potential of coordination modules present in 1 and 2 in bringing about generality and diversity of C-H···Cl hydrogen bonding interactions. Special attention has been directed to the influence of additional (i) coordinated solvent molecule, which can act as hydrogen bond donor/acceptor and (ii) chloride ion in the assembly of supramolecular architectures via noncovalent interactions. Inorganic supramolecular synthons 1 and 2 give rise to molecular staircase and zig-zag network, respectively. Re-examination of previously reported compound [(L⁶)ZnCl₂] with extended limit of hydrogen bonding interaction reveals additional helical network.