Dmso d6

All the chemicals were purchased from Sigma Aldrich and were used as received. The compounds synthesized by the general procedure described below and were characterised by mass spectrometry and ¹H and ¹³C NMR spectra recorded on 600 MHz JEOL NMR spectrometer in either CDCl₃ or DMSO-d₆ with TMS as an internal reference at Central University of Punjab, Bathinda (¹H NMR: TMS at 0.00 ppm, CDCl₃ at 7.26 ppm, DMSO-d₆ at 2.5 ppm; ¹³C NMR: CDCl₃ at 77.16 ppm, DMSO-d₆ at 39.52 ppm). The spectroscopic data of all the synthesized compounds are consistent with the reported datas.^{42 (link)}

Analytical reagent grade salicylaldehyde,
acetylacetone, 1,3-diaminoguanidine monohydrochloride, DMSO-d₆ (Sigma-Aldrich, USA), and V₂O₅ (Himedia, India) were used as procured. Other chemicals and
solvents used in this study were procured from standard sources. Precursor
[V^IVO(acac)₂]^{53 (link)} was
prepared following the literature method.
All measurements were
made after drying the ligands and complexes at 100 °C. The CHN
analysis of all complexes were carried out on an elementar model Vario-EL-III
element analyzer. Infrared (IR) spectra were recorded with KBr pellets
on a Nicolet 1100 FT-IR spectrometer. Electronic spectra of the ligands
and complexes were recorded in DMSO on a Shimadzu 2600 UV–vis
spectrophotometer. ¹H, ¹³C, and ⁵¹V NMR spectra were recorded in DMSO-d₆ on a Jeol 500 MHz spectrometer. The electron paramagnetic resonance
(EPR) spectra of the complexes were recorded in DMSO at 100 K on a
Bruker Biospin EMXmicro A200-9.5/12/S/W spectrometer. High-performance
liquid chromatography (HPLC) was performed on a Shimadzu LC-2010A
HT instrument in the low-pressure gradient mode with a flow rate of
0.5 mL min^–1 and an injection volume of 15 μL.