Synthesis and Characterization of New Lead(II) and Organotin(IV) Complexes of Schiff Bases Derived from Histidine and Methionine

Abstract

New Schiff base (HL) ligand is prepared via condensation of isatins and amino acids in 1:1 molar ratio. Metal complexes are prepared and characterized by elemental analysis, molar conductance, electronic, infrared, and multinuclear magnetic resonance ( 1 H NMR, 13 C NMR, and 119 Sn NMR). The analytical data showed that the ligand acts as bidentate toward metal ions via azomethine nitrogen and carboxylate oxygen by a stoichiometric reaction of metal : ligand (1 : 2) to from metal complexes (Pb(II)(L) 2 and Bu 2 Sn(L) 2 , where L is the Schiff base ligands of histidine and methionine). The conductivity values between 15 and 25 Ω −1 cm 2 mol −1 in DMF imply the presence of nonelectrolyte species. On the basis of the above spectral studies, distorted octahedral and tetrahedral geometry have been proposed for the resulting organotin(IV) and lead(II) complexes.

Synthesis of Schiff bases derived from 2-hydroxy-1- naphth- aldehyde and their tin(II) complexes for antimicribial and antioxidant activities

“…The (COO -) bands at 1541 cm -1 and 1390 cm -1 for asymmetric and symmetric stretching in ligands are shifted to 1496 cm -1 and 1311 cm -1 in complexes. A new band at 3404 cm -1 is ascertained in the spectra of complex only and is assigned to υ(H 2 O) [8,10,12].…”

“…The tin ion has vacant 5d orbital and consequently ligand-to-metal (L→M) binding can take place by the acceptance of pair of electrons from ligand to the tin metal. No d-d transition is expected for tin complexes [8,12,15,17,26,27]. …”

“…Schiff bases are important due to carbon nitrogen double bond (C=N) which can coordinate with metal [3]. These important compounds have been reported to possess diverse biological activities such as antifungal, analgesic, anti-inflammatory, antibacterial, antioxidant, antitumor, cardiovascular, antitubercular [4][5][6][7] and as local anesthetic [8]. Apart from these synthetic imine groups are synthesized in labs various natural products compounds.…”

Synthesis of New Zirconium(IV) Complexes with Amino Acid Schiff Bases: Spectral, Molecular Modeling, and Fluorescence Studies

“…Sandhu and Verma in their studies and reports have shown that the Δ value of complexes greater by 65-90 cm −1 than in their sodium salts indicates either asymmetric or monodentate bonding of the carboxylate group to metal atom [32]. Moreover, Δ values of complexes below 200 cm −1 would be expected for bridging or chelating carboxylates, but greater than 200 cm −1 for the monodentate bonding carboxylate anions [33]. The C=O band of the indole group appears in the range of 1720-1740 cm −1 in the ligands.…”

Synthesis and Characterization of New Schiff Base/Thiol-Functionalized Mesoporous Silica: An Efficient Sorbent for the Removal of Pb(II) from Aqueous Solutions

“…It can be seen that the results for the Pb(II) ions loaded sample were almost same as the pre-adsorption sample, However, some of the bands after lead ions were loaded shifted to a lower value than that of the pre-adsorption sample, confirming the adsorption of the Pb(II) ions on the silica surface. This suggests the involvement of the oxygen atom of the carboxylate anion with the azomethine nitrogen and the Pb(II) ion [35]. The infrared spectrum in Figure 2b revealed the asymmetric stretching vibration of ν as (COO − ) of adsorbent 1 at 1665 cm −1 was shifted to a lower wave number (1642 cm −1 ) after the Pb(II) ion was loaded, indicating that the lead ion coordination took place via the oxygen atom of the carboxylate anion [36].…”