Preparation and Crystal Structure of N,N΄-bis(2,4-dimethoxybenzylidene)-butane-1,4-diamine Monohydrate

In this work, the Schiff-base compound N,N΄-bis(2,4-dimethoxybenzylidene)-butane-1,4-diamine monohydrate ((2,4-MeO-ba)2bn/H2O) was prepared by the condensation reaction of 2,4-dimethoxybenazaldehyde with butane-1,4-diamine in methanol solution and crystallizes as the monohydrate. The crystal structure of (2,4-MeO-ba)2bn/H2O (1) was determined using the X-ray diffraction (XRD) analysis. The compound crystallized in the monoclinic space group C2/c, with a=14.7116 (10), b=15.7333 (9), c=10.2013 (6) Å, β=112.704 (2)° and Z=4. There are one half-molecule and one half of a water molecule in the asymmetric unit, with the (2,4-MeO-ba)2bn molecule completed by inversion symmetry on the midpoint of the central C-C bond of the butane unit and the O atom of the water molecule situated on a twofold rotation axis.  Within the imine functionality, the N-C bond lengths of 1.2643 (19) and 1.457 (2) Å were double and single bonds, respectively. Hydrogen bonds of the type O-H∙∙∙N between the water molecule and the imine nitrogen atom of the (2,4-MeO-ba)2bn molecules led to formation of the layers propagating parallel to (100). The 1H-NMR and FT-IR results confirmed the preparation of this ligand, as well.