title: A competitive molecular recognition study: syntheses and analysis of supramolecular assemblies of 3,5-dihydroxybenzoic acid and its bromo derivative with some N-donor compounds.
abstract: A molecular recognition study of 3,5-dihydroxybenzoic acid (1) and its bromo derivative 4-bromo-3,5-dihydroxybenzoic acid (2) with the N-donor compounds 1,2-bis(4-pyridyl)ethene (bpyee), 1,2-bis(4-pyridyl)ethane (bpyea), and 4,4'-bipyridine (bpy) is reported. Thus, the syntheses and structural analysis of molecular adducts 1 a-1 c (1 with bpyee, bpyea, and bpy, respectively) and 2 a-2 c (2 with bpyee, bpyea, and bpy, respectively) are discussed. In all these adducts, recognition between the constituents is established through either O--H...N and/or O--H...N/C--H...O pairwise hydrogen bonds. In all the adducts both OH and COOH functional groups available on 1 and 2 interact with the N-donor compounds, except in 2 a, in which only COOH (COO-) is involved in the recognition process. The COOH moieties in 1 a, 1 b, and 2 b form only single O--H...N hydrogen bonds, whereas in 1 c and 2 c, they form pairwise O--H...N/C--H...O hydrogen bonds. In addition, subtle differences in the recognition patterns resulted in the formation of cyclic networks of different dimensions. In fact, only 1 c forms a four-molecule cyclic moiety, as was already documented in the literature for this kind of assemblies. All complexes have been characterized by single-crystal X-ray diffraction. The supramolecular architectures are quite elegant and simple, with stacking of sheets in all adducts, but a rather complex network with a threefold interpenetration pattern was found in 2 c.
authors.affiliation: Solid State & Supramolecular Structural Chemistry Lab, Division of Organic Chemistry, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
authors.forename: Sunil
authors.initials: S
authors.lastname: Varughese
authors.forename: Venkateswara Rao
authors.initials: VR
authors.lastname: Pedireddi
mesh_terms: D017605:Bromine Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D003460:Crystallization; D062385:Hydroxybenzoates / Q000138:chemical synthesis* / Q000737:chemistry; D007202:Indicators and Reagents; D008958:Models, Molecular; D008968:Molecular Conformation; D012118:Resorcinols; D014961:X-Ray Diffraction
chemical_list: D017605:Bromine Compounds; D062385:Hydroxybenzoates; D007202:Indicators and Reagents; D012118:Resorcinols; C076950:alpha-resorcylic acid