Synthesis, spectral and quantum chemical studies on NO-chelating sulfamonomethoxine–cyclophosph(V)azane and its Er(III) complex

Synthesis and Spectral Characterization Studies of New Trimethoprim-Diphenylphosphate Metal Complexes

“…However, the 1 H NMR spectrum of ligand shows a singlet at 9.75 ppm corresponding to OH groups which suggest the existence of ligand in enolic form in solution. The 31 P NMR of the ligand records a signal at δ=14.45 ppm, which supports the phosphenous amide group [18][19][20][21]. In the 13 C NMR spectrum three peaks at 163.8 ppm, 158.8 ppm, 58.3 ppm and 32.5 ppm were observed, being assigned to C=N, C-OP, CH 2 and CH 3 , respectively.…”

“…The electronic spectrum of DPTMEBPP in ethanol showed absorption bands at 240-390 nm regions which is due to intraligand π → π* and n → π* transitions involving molecular orbital of the pyrimidine ring, a broad shoulder at approximately 432 nm were observed. The latter band is attributed to an n(oxygen) → π* transition of the dipolar zwitter ionic structure or keto-amine tautomer of DPTMEBPP [18][19][20][21]. The electron impact mass spectrum (Figure 2) …”

“…The ligand DPTMEBPP may show keto-enol tautomerism because it contains the phosphenous amide (-NH-P=O) bonds [18][19][20][21]. The IR spectrum does not show a ν(OH) band at or 3400 cm -1 but shows the band at 3273 cm -1 corresponding to ν(NH) [18][19][20][21], indicating that in solid state, the ligand exists in the keto form for the ligand DPTMEBPP. However, the 1 H NMR spectrum of ligand shows a singlet at 9.75 ppm corresponding to OH groups which suggest the existence of ligand in enolic form in solution.…”

“…In the IR spectra of the complexes, a bands are observed at 270-294 and 320 -328 cm −1 that is attributed to the ν(M-N) [22] and ν(M-Cl) [22] stretching vibrations, respectively. Another band appeared between 332 and 342 cm −1 , which is assigned to the interaction of phenolic oxygen to the metal atom, i.e., the stretching vibrations ν(M-O) [21]. Also, in the IR spectra of the complexes, a bands are observed at 187-193 and 216-233 cm −1 that is attributed to the ν(O-M-O) and ν(O-M-N) [23,24] stretching vibrations, respectively.…”

Synthesis, characterization, biological evaluation, and molecular docking approach of nickel (II) complexes containing O, N‐donor chelation pattern of sulfonamide‐based Schiff bases

“…This is accompanied by disappearance of either the twin bands of ν (NH 2 ) or ν (NH) in case of L 1 and L 2 , respectively, substantiating the enolization process of the sulfonamide group SO 2 NH (H) to SO (OH) = N(H) before coordination as reported by previous studies of metal-sulfa drugs based chelates of a dinuclear feature (M 2 L). [27,28] Accordingly, there is an interaction between the metal ion with the sulfonamidic-N and sulfonyl-O atoms of L 1 through four-membered ring formation in case of complex (1). [29,30] As well, the blue shift and the weakness of the ν(C=N) at 1532 cm À1 of the thiazole moiety of L 2 in the spectra of its complex (2) favoring the chelation of the thiazole-N atom to give more stable sixmembered ring.…”