Synthesis, spectral characterization, DFT studies and biological activity of novel Ligand 1‐(2‐cyclohexyl thioethyl) piperidine and its complexes with group 12 metal chlorides

• Published in: Applied organometallic chemistry 2018-05, Vol.32 (5), p.n/a
• Main Authors: Bhat, Muzzaffar A., Lone, Shabir H., Mir, Muzzaffar A., Majid, Sheikh A., Srivastava, Sanjay K.
• Format: Article
• Language: English
• Subjects: Antibacterial; antifungal; bidentate; Biological activity; Chemical potential; Chemical synthesis; Chemistry; Coordination compounds; density functional theory; Diffraction patterns; Energy gap; Fungicides; Ligands; Mathematical analysis; Mercury compounds; Metal chlorides; Metals; Molecular orbitals; NMR; Nuclear magnetic resonance; Piperidine; Zinc chloride
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.4329

C6H11S‐Na+ (generated insitu by reaction of NaOH with C6H11SH) on treatment with 1‐(2‐chloroethyl) piperidine hydrochloride under N2 atmosphere resulted in (1‐(2‐cyclohexyl thioethyl) piperidine) (L1) as orange solid. It's complexes having the formula [ZnCl2. L1] (1), [CdCl2. (L1)] (2) and [HgCl2. L1] (3) have been prepared. L1 and its complexes 1‐3 were characterized on the basis of physico‐chemical and spectral (FT‐IR, Mass, 1H, 13C and DEPT 135o NMR) studies. Powder XRD diffraction pattern reveals the crystalline nature of L1 and complex 1. Complexes 1‐3 adopt distorted tetrahedral geometry showing bidentate mode of coordination through S and N. Using DFT‐based optimization of structures, the HOMO‐LUMO energy gaps and molecular electrostatic potential maps (EPM) of compound L1 and complexes 1‐3 were theoretically calculated at the B3LYP/6‐311G (d, p) level of theory. HOMO‐LUMO energy gap was calculated which allowed the calculation of relative properties like chemical hardness, chemical inertness, chemical potential, nucleophilicity and electrophillicity index of the synthesized products. The experimentally obtained IR and NMR results showed a good correlation with those of the theoretical ones. Ligand L1 and complexes 1‐3 display significant antibacterial and antifungal activity. Formation of L1 is the first example of novel synthesis where 1‐(2‐chloro ethyl) piperidine hydrochloride and cyclohexyl thiol is used, which results in the formation of (S, N) hybrid donor ligand. Ligand L1 ligates through both N and S thus adopts bidentate mode of coordination in complexes 1‐3. Using DFT‐based optimization of structures, the HOMO‐LUMO energy gaps and molecular electrostatic potential maps (EPM) of compound L1 and complexes 1, 2 and 3 were theoretically calculated at the B3LYP/6‐311G (d, p) level of theory. Ligand L1 and complex 1‐3 display significant antibacterial and antifungal activity.