Search

Metal complexes based on mono(arylhydrazino)acenaphthenones (Ar-mhan) are extremely rare. In this work, synthetic routes for previously unknown rhodium complexes containing 2-(pyridin-2-yl)hydrazino acenaphthene-1-one (Py-mhan) are proposed. The interaction of RhCl3·3H2O with Py-mhan, depending on the conditions, led to two anionic complexes: (HPy-mhan)+[Rh(Py-mhan)Cl3] (1) and (NBu4)[Rh(Py-mhan)Cl3] (2). The complexes were characterized using X-ray diffraction analysis, elemental analysis, and IR- and 1H NMR-spectroscopies. The electrochemical properties of complex 2 were investigated using cyclic voltammetry. Complex 2 demonstrated irreversible reduction at −0.69 V (vs. Ag/AgCl), which is accompanied by the elimination of chloride ligands to give a Rh(I) complex namely [Rh(Py-mhan)(CH3CN)] (3). Complex 3 was isolated by electroreduction of complex 2 on a carbon glass electrode and characterized by EDS analysis, CHN analysis, 1H NMR spectroscopy and cyclic voltammetry. For complexes 2 and 3, reversible reduction processes localized on Py-mhan were found. To confirm the nature of electrochemical transformations for complexes 2 and 3 in solution, quantum chemical calculations were performed. [ABSTRACT FROM AUTHOR]

Three mono(arylhydrazino)acenaphthenones, that is, mono(2-pyridylhydrazino)acenaphthenone (Py-mhan, L1), mono(4-cyanophenylhydrazino)acenaphthenone (4-CN-Ph-mhan, L2), and mono(3,4,6-trifluoro-2-pyridylhydrazino)acenaphthenone (FPy-mhan, L3), were synthesized by the reaction of acenaphthene quinone with the appropriate arylhydrazine salt; compounds L2 and L3 were obtained for the first time. The subsequent reaction of L1 with nickel chloride in 2 : 1 ratio led to the octahedral complex [Ni(Py-mhan)2] (I), in which Py-mhan acts as a tridentate ligand. All of the prepared compounds were characterized by elemental analysis, IR and 1H NMR spectroscopy, and cyclic voltammetry; the crystal structures of L3 and I were determined by X-ray diffraction. [ABSTRACT FROM AUTHOR]

A new synthetic procedure for mono(arylhydrazino)acenaphthenones Ph-mhan (1) and 2-tol-mhan (2), based on the reaction of acenaphthenequinone with an arylhydrazonium salt, has been developed. These compounds were used further to obtain a series of heteroleptic cationic palladium(II) complexes containing bis(arylimino)acenaphthene (Ar-bian) and mono(arylhydrazino)acenaphthenone (Ar-mhan) ligands: [Pd(tmp-bian)(Ph-mhan)](CF3SO3)2 (3), [Pd(tmp-bian)(2-tol-mhan)](CF3SO3)2, (4), and [Pd(dpp-bian)(Ph-mhan)](CF3SO3)2 (5). The resulting compounds were characterized by X-ray diffraction analysis, 1H NMR, IR and UV spectroscopy, cyclic voltammetry, and quantum chemical calculations. All complexes show a reversible reduction at −0.31 to −0.41 V (vs. Ag/AgCl) localized on the Ar-bian ligand, followed by an irreversible reduction at −1.27 to −1.46 V (vs. Ag/AgCl) of the Ar-mhan moiety. Electronic absorption spectra of 3–5 reveal a characteristic band in the near-IR region (∼700 nm), corresponding to the intramolecular ligand-to-ligand charge transfer (LL′CT) from Ar-mhan (π-donor) to Ar-bian (π-acceptor). [ABSTRACT FROM AUTHOR]