Synthesis and Characterization of Some Dibasic Tridentate Schiff Base Ligands

Abstract

The synthesis and characterisation of several dibasic tridentate Schiff base ligands (H2SB) are described. Structural formulas for the isolated ligands are suggested on the basis of infrared, nuclear magnetic resonance, and mass spectral data.

The synthesis, structural characterization and biocidal properties of some triorganotin(IV) esters ofN-arylidene-?-amino acids.

“…This assignment was substantiated by the broad infrared absorptions in the region 2600-3400 cm À1 which are reported to be due to intramolecular hydrogen bonding between the phenolic proton and the azomethine nitrogen. 16 The quadrupole splitting (q.s. ), isomer shift (c.s.)…”

Interaction of metal ions with d-glucobenzothiazoline: isolation and characterization of the resultant products

“…EPR spectra were recorded in the solid phase as well as in Me 2 SO solution on a Bruker ESP-300 spectrophotometer operating in the X-band mode at 300 and 77 K using 1,1-diphenyl-2%-picrylhydrazyl (DPPH) (g e 2.0023) as a field marker. The 1 H and 13 C NMR spectra were measured on a Bruker Avance DRX500 spectrometer operating at 500 MHz for 1 H and 126 MHz for 13 C nuclei. FTIR spectra were recorded on an Impact 400 Nicolet FTIR spectrometer in KBr matrix in the region of 400-4000 cm − 1 .…”

“…-The peaks observed in the 1 H and the 13 C NMR spectra of the metal-ion complexes, 1, 2, and 4-6, were assigned by comparing these with the spectrum of H 6 L. The comparisons revealed the formation of the metal-ion complexes. The proton signals of NH and OH were identified in the D 2 O exchange studies.…”

“…and this makes the C-1 center of the saccharide susceptible to undergo intramolecular nucleophilic rearrangement at O-4, resulting in the formation of a furanose ring structure. 13 Interaction of hydroxyl groups with the metal ions is noticed based on the shifts observed in the l values of the corresponding carbon centers of the saccharide moiety. Binding abilities of the S-center with the central metal ion varies from one complex to another as shown by the downfield shift (DlCS, ppm) observed with the metal-ion complexes, 1 (3.8), 2 (2.9), 4 (3.0), and 5 (9.3) when compared to the ligand H 6 L. Binding of the glycosyl NH group is further supported by the downfield shift (DlC-1, ppm) observed in the anomeric carbon of the metal-ion complexes, 1 (8.7), 2 (5.1), 4 (8.9), and 5 (1.0), as compared to that in the ligand H 6 L. The variation observed in the downfield shift seems to reflect on the binding ability as well as on the hard-soft character of the corresponding metal ions.…”

“…-Benzothiazoline derivatives 13 are versatile ligands having potential N-, S-, O-donor atoms and can coordinate in mono and/or in bidentate fashion. While the ligand H 6 L exhibited resonances corresponding to five OH groups, which is consistent with the open-chain form, the metalion complexes, 1, 2, and 4 -6 exhibited only four OH groups due to the formation of a furanose ring.…”