ORIGINAL PAPER Hydrogen Bonding Patterns and DFT Studies of (4- Acetylphenyl)amino 2,2-Dimethylpropanoate and (E)-1-(4- Aminophenyl)-3-[4-(dimethylamino)phenyl]prop-2-en-1-one Rama Kant • Biswajit Maiti • Satish Kumar Awasthi • Alka Agarwal Received: 14 March 2014 / Accepted: 3 July 2014 Ó Springer Science+Business Media New York 2014 Abstract The (4-acetylphenyl)amino 2,2-dimethylpropan- oate (1) and (E)-1-(4-aminophenyl)-3-[4-(dimethylamino) phenyl]prop-2-en-1-one (2), were synthesized and charac- terized by elemental analysis, FT-IR, 1 H NMR, 13 CNMR and single crystal X-ray diffraction techniques. Both compounds 1 and 2 crystallized in orthorhombic crystal system with Pbca and P212121 space group respectively, having the unit cell parameters: a = 11.7220(12) A ˚ , b = 14.4580(13) A ˚ , c = 15.7853(12) A ˚ , b = 90°, Volume = 2675.2(4) A ˚ 3 ,Z = 8 for 1 and a = 6.1146(5) A ˚ , b = 9.0567(8) A ˚ , c = 26.079(3) A ˚ , b = 90°, Volume = 1444.2(2) A ˚ 3 ,Z = 4 for compound 2. The crystal structures of both compounds (1 and 2) are stabilized by N–HÁÁÁO strong intermolecular hydrogen bonding forming C 1 1 (8) motifs. In compound 1, the molecules are linked by three C–HÁÁÁO intramolecular H-bond forming S(6) motifs. In compound 2, the molecules are linked by C–HÁÁÁN intermolecular H-bond exhibiting C 1 1 (12) motif and C–HÁÁÁO intramolecular H-bond leading to S(5) motif. Crys- tallographic and vibrational data are compared with the results of density functional theory (DFT) method at the B3LYP/6- 31G(d,p) level. The electronic (UV–vis) spectra was calcu- lated by using the TD-DFT method and correlated with experimental spectra. Keywords Hydrogen bonding Á DFT Á Graph-set motifs Á (4-Acetylphenyl)amino 2,2-dimethylpropanoate Á (E)-1-(4-aminophenyl)-3-[4-(dimethylamino)phenyl] prop-2-en-1-one Introduction Chalcones are Michael acceptors, bearing the 1,3-diaryl-prop- 2-en-1-one framework which are usually prepared by Claisen– Schmidt condensation method between aromatic aldehydes and ketones under homogeneous conditions. They contain two aromatic rings which are joined through a, b unsaturated ketone, and this unique structure is responsible for various activities of these molecules [1]. Chalcones are naturally occurring compounds which belong to the flavonoid family [1, 2], and used for drug design and development. During the past decade, synthetic modifications in chalcones skeleton enhance their bioactivities. The chalcones and their derivatives have excellent anticancer [3, 4], antimalarial [5], anti-inflammatory [6], antileishmanial [6], antituberclulosis [7], nitric oxide inhi- bition [8], antimitotic [9], analgesic, antipyretic, antioxidant [10, 11], antibacterial, anti-HIV [12], antifungal [13], antipro- tozoal activities [14], and are also reported to be gastric pro- tectant [15], antimutagenic, and antitumorogenic [16]. The commercially available 4-aminoacetophenone is used in syn- thesis of flavaniline [17], antibacterial [18], anti-inflammatory [19], anti HIV [20] agents and an oral hypoglycemic drug such as acetohexamide [21]. In the view of the above mentioned facts, we designed and synthesized (4-acetylphenyl)amino-2,2- dimethylpropanoate (1) and (E)-1-(4-aminophenyl)-3-[4- (dimethylamino)phenyl]prop-2-en-1-one (2) (Scheme 1). Our research group mainly works on antimicrobial compounds [22, 23]. Recently we have reported several X-rays analysis of small molecules [24–30]. In this study, we are reporting for the first R. Kant Á A. Agarwal (&) Department of Medicinal Chemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi 225001, UP, India e-mail: alka_ag_2000@yahoo.com B. Maiti Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 225001, UP, India S. K. Awasthi Chemical Biology Research Laboratory, Department of Chemistry, University of Delhi, Delhi 110007, India 123 J Chem Crystallogr DOI 10.1007/s10870-014-0533-3