N-(acyl)- $$\textit{N}^\prime $$ N ′ -(ferrocenylidene)hydrazines and their nickel(II) complexes: Syntheses, structures and physical properties

Abstract

The Schiff bases N-(acyl)-N-(ferrocenylidene)hydrazines (HFcah (1) and HFcbh (2), where acyl = acetyl in 1 and benzoyl in 2 and H represents the dissociable amide proton) were synthesized in high yields (74 and 81%) by condensation reactions of equimolar amounts of ferrocene-carboxaldehyde and the corresponding acylhydrazines in presence of acetic acid in refluxing methanol. Reactions of Ni(OAc) 2 •4H 2 O, the Schiff bases (1 and 2) and NaOAc • 3H 2 O in 1:2:4 mole ratio in refluxing methanol afforded the diamagnetic iron(II)-nickel(II)iron(II) species [Ni(Fcah) 2 ] (3) and [Ni(Fcbh) 2 ] (4) in 60 and 68% yields, respectively. Both Schiff bases and the two trinuclear complexes were characterized by elemental (CHN) analysis, mass spectrometric, various spectroscopic (IR, UV-Vis and 1 H NMR) and cyclic voltammetric measurements. Molecular structures of 2, 3 and 4 were determined by single crystal X-ray diffraction studies. The cyclopentadienide rings in the ferrocene moieties are essentially in eclipsed conformation in all three structures. Deprotonated Schiff base ligands in each complex (Fcah − in 3 and Fcbh − in 4) act as five-membered chelate ring forming azomethine-N and amidate-O donors and assemble a square-planar trans-N 2 O 2 coordination environment around the nickel centre. The redox active 1-4 exhibit an iron centred redox couple in the potential range 0.23-0.50 V (vs. Ag/AgCl).

Bis-ferrocenyl-hydrazide metal complexes: studying electronic functional groups as newly potent homogeneous photocatalysts for C(sp3)–H and C(sp2)–H bond oxidation utilizing visible light condition

“…These red organometal complexes were filtered and purified with water and hot methanol. 48 We performed this strategy for the synthesis of our new [(FcHz-X) 2 Ni] and [(FcHz-X) 2 Cu] complexes, as outlined in Scheme 1. After the successful preparation of the [(FcHz-X) 2 Ni] and [(FcHz-X) 2 Cu] complexes, they were identified with various spectroscopy and non-spectroscopy methods, including FT-IR, NMR ( 1 H), XRD, XRF, XPS, SEM, TGA, EDX, photocurrent, cyclic voltammetry, and UV-visible spectroscopy.…”

“…When the process was augmented, the red precipitates were separated and washed with hot methanol and water several times. 48 A common method for C-H (sp 3 ) oxidation processes A blend of p-nitro toluene (1 mmol) and cesium carbonate (0.3 mmol, ≃0.1 g) in MeCN : H 2 O 1 : 1 (2 mL) was placed in the test tube (16 mm). ([(FcHz) 2 Ni]) and ([(FcHz) 2 Cu]) (5 mg) were added and the tubes of the processes were illuminated by 12 W LED lamps at the previously described homemade photoreactor system for the appropriate time (48 h).…”

“…When the process was augmented, the red precipitates were separated and washed with hot methanol and water several times. 48…”