Synthesis and spectroscopic characterization of nicotinaldehyde based derivatives: SC-XRD, linear and non-linear optical studies

In this study, new arylated derivatives of pyridine named as 6-(4-tertbutylphenyl)-nicotinaldehyde ( TBPNA ) and 6-(4-hydroxyphenyl)-nicotinaldehyde ( HPNA ) were synthesized by Suzuki Miyaura C -C coupling approach. The structures of newly synthesized compounds were authenticated by spectroscopic techniques like FT-IR, UV-Vis, and (1) H-NMR. Furthermore, the structural features of TBPNA and HPNA were explored by using the single-crystal X-ray diffraction technique (SC-XRD) showing monoclinic crystal structure and P2 (1) /c space group for both compounds. For a comprehensive study of the compounds, a computational quantum chemical study is also performed by using the density functional theory (DFT). The said compounds were optimized using the B3LYP method and a 6-311 ++ G(d, p) basis set. The comparison of theoretical (DFT) and experimental (SC-XRD) data on structural parameters displayed good agreement. Frontier molecular orbital (FMO), natural bond orbital (NBO), the molecular electrostatic potential (MEP), and time-dependent density functional theory (TD-DFT) were also performed at the B3LYP/6-311 ++ G(d,p) level of theory to get complete insights into electronic communications, intramolecular charge transfer (ICT) process, electronic transition and oscillation strength. The optoelectronic and non-linear optical (NLO) responses of the synthesized compounds were determined by computing the total dipole moment ( mu tot ), average polarizability ( alpha) , and the first hyperpolarizability ( P-tot ) at different functional(s) such as HF, M06, M062X, CAM-B3LYP, LC-BLYP, and B3LYP, paired with the 6311 ++ G(d,p) basis set. The B3LYP method exhibited the highest values of ( alpha) and ( P-tot ) for HPNA and TBPNA , which were found to be many times higher than the value of urea ( ( alpha) = 34.055 a.u., beta(tot )= 90.527 a.u.), used as a standard NLO material. (C) 2022 Elsevier B.V .All rightsr eserved