Study of molecular and electronic structure of a new proton transfer compound with 2,6–pydc and py–3–cm: Synthesis and DFT calculations

Document Type : Original Article

Author

• Mahmood Ebrahimi

Department of Chemistry, Faculty of basic science, Hakim Sabzevari University, Sabzevar

Abstract

Two donor (D) and acceptor (A) proton groups through transferring one or more proton construct the proton transfer compounds (PTCs). The successful synthesis of these compounds depends on the precise choosing of D and A. Therefore, carboxylic acids and amines and amides act as D and A moiety and making a ligand of coordination compounds. Herein, at first the colorless crystals of a new PTC named 2,6–pydc(py–3–cm) because of reaction of pyridine–2,6–dicarboxilic acid (2,6–pydc) and pyridine–3–carbocxamide (py–3–cm) was prepared and its structure using FTIR, UV–Vis and CHNS analysis characterized. Finally, using the Gaussian 09 program the required DFT calculations including geometry optimization, frequency, TD, and NBO B3LYP/6–311+G(d, p) ones about the proposed structure was executed. The comparison of FTIR spectra of prepared 2,6–pydc(py–3–cm) with the related vibrational bands of D and A confirm the formation of inter–molecular hydrogen bond (HB). The theoretical electronic transitions spectrum confirms the experimental one derived from n (p) → π* and π → π* Intra–Ligand Charge Transfer (ILCT) transitions. In addition, the calculated stabilization energy of the prepared PTC with O−H···N and C−H···O HBs measured as –67.36 kcal mol–1.

Keywords

• Proton transfer Compound
• 2,6–pydc(py–3–cm)
• Synthesis
• Hydrogen bond
• DFT
• NBO

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