Two Zn(II) and one Mn(II) complexes using two different hydrazone ligands: spectroscopic studies and structural aspects

Abstract

Three new coordination complexes of Zn(II) and Mn(II) have been synthesised using two different tridentate N,N,O donor hydrazone ligands, Hpbh and Hacpbh respectively. The complexes [Zn(pbh) 2 ] (1) and [Zn (acpbh) 2 ] (2) have been synthesized by the treatment of ZnSO 4 Á 7H 2 O with Hpbh and Hacpbh hydrazone ligands, respectively. The Mn(II) complex [Mn(acpbh) 2 ] (3) was obtained on reacting Mn(NO 3 ) 2 Á 4H 2 O with the ligand Hacpbh.The ligands Hpbh and Hacpbh were prepared by condensing pyridine-2-carboxaldehyde and 2-acetylpyridine with benzhydrazide respectively. Inspite of varying the carbonyl functionality attached to the pyridine moiety present in the hydrazone ligands in both the Schiff bases, we obtained three mononuclear complexes 1, 2, and 3 which were clearly characterized from single crystal X-ray diffraction studies. Spectroscopic investigations like IR and UV/Vis have been carried out for 1, 2, and 3. Fluorescence studies have been performed for 1 and 2. For 3 cyclic voltammetry, room temperature magnetic study and EPR measurements have been recorded.

Chemistry of molecular and supramolecular structures of vanadium(IV) and dioxygen-bridged V(V) complexes incorporating tridentate hydrazone ligands

“…The IR spectra of the ligands exhibit two bands at ca. 3089 and 1672 cm À1 due to the m(NH) and m(C@O) stretches, respectively, and are indicative of their ketonic nature in the solid-state [27,28]. The existence of the ligand in the keto tautomer form was confirmed from the crystal structure determination (see above).…”

Structural Studies and Investigation on the Activity of Imidazole-Derived Thiosemicarbazones and Hydrazones against Crop-Related Fungi

“…Three signals for all hydrogens and carbons were found in the 1 H-and 13 C-NMR spectra of compound 9, suggesting the existence of three isomers in solution. The signals of C5 at δ 171.89 and δ 171.57 were attributed to C=O of the E and Z isomers, respectively, and the signal at δ 168.35 was assigned to C-OH in the enol tautomer [29].…”

“…Due to the low solubility of 12 it was impossible to record its C-NMR spectra of compounds 13 and 17 showed duplicated signals for each hydrogen and carbon indicating the presence of two isomeric forms in solution. The signals at δ 172.00 and δ 165.67 for 13 and δ 171.82 and δ 166.13 for 17 corresponded to C11=O and C11-OH of the keto and enol tautomers, respectively [29]. The signals at δ 11.49 and δ 10.51 were attributed to N4-H in the keto tautomer for 13 and 17, and those at δ 11.35 and δ 10.41 to O-H in the enol tautomer, respectively.…”

Three new coordination complexes of cobalt(III), manganese(II), and copper(II) with N,N,O-donor hydrazone ligands: syntheses and structural characterizations

“…Considering the importance of the transition metal complexes with various aroylhydrazones, our group has reported a number of examples [16][17][18][19][20][21][22][23] including two Cu(II) and Co(III) complexes with an aliphatichydrazone ligand [24]. Transition metal complexes with 2-pyridinecarboxaldehyde-salicyloylhydrazone and 2-acetylpyridine-salicyloylhydrazone are well characterized.…”