Photochemical reactions of group VIB metal carbonyls with heterocyclic Schiff bases derived from 4-amino -3-hydrazino-5-mercapto-1,2,4-triazole

New diorganotin(IV) complexes of Schiff base derived from 4‐amino‐3‐hydrazino‐5‐mercapto‐4H‐1,2,4‐triazole: Synthesis, structural characterization, density functional theory studies, atoms‐in‐molecules analysis and antifungal activity

“…The experimental chemical shifts for magnetically non‐equivalent protons and carbon atoms relative to TMS, and coupling constant data of HL and complexes 1 and 2 are presented in Section and also in Tables S2 and S3. The assignments of the 1 H NMR and 13 C NMR resonances are in accordance with the reported values for organotin(IV) alkoxides, and metal complexes of hydrazino Schiff bases …”

“…The appearance of these bands suggests a nonlinear C–Sn–C configuration in complexes 1 and 2 . The observed changes in the FT‐IR spectra of the studied organotin(IV) complexes with respect to free HL suggest that the hydrazino Schiff base ligand is coordinated to the organotin(IV) moiety via O phenolic and N azomethine , as reported previously for several organotin(IV) alkoxides and metal complexes of hydrazino Schiff bases …”

“…In the studied complexes, the observed change in the chemical shift (10.90–10.51 ppm) of NH exocyclic (NH hydrazino adjacent to the azomethine group) as compared to free HL (10.86 ppm) also suggests the coordination of N azomethine to the central tin atom of the organotin(IV) moiety. In HL and complexes 1 and complex 2 , the singlet observed at 12.98–12.96 ppm due to the NH endocyclic (NH function of the triazole ring) indicates that the Schiff base exists in thione form, which is further confirmed by the absence of a signal at 2.0–4.0 ppm attributed to ─SH protons. The absence of resonance due to the thiol (SH) proton in complexes 1 and 2 confirms that the thione tautomer is the dominant species of HL in solution .…”

“…The statistical analysis suggests a good correlation ( R 2 = 0.9964–0.9973) between experimental and simulated IR vibrational frequencies. Tentative assignments were made by comparing the spectra of the synthesized complexes 1 and 2 with that of HL, and reported organotin(IV) complexes of Schiff bases with hetero donor atoms and metal complexes of hydrazino Schiff bases …”