Synthesis, structural and spectroscopic studies of novel azo-containing N,O-bonded complexes in the α-Iminoketone and Azophenolate forms

Abstract

Este artigo descreve a síntese e a caracterização espectroscópica e estrutural por difratometria de raios X em monocristal de dois novos complexos contendo o grupamento azo, cis-bis[4-nitro-2-(4-nitrofenilazo)-fenolato-κN 1 ]bis(piridino-κN)cádmio(II), 1, e cis-bis[2-(4-fenilazofenilimino)-2H-acenafteno-1-ona]dicloromercúrio(II), 2. Embora os ligantes e os metais sejam diferentes, observa-se para os dois complexos uma coordenação do tipo N,O-bidentada ao átomo central. Em 1, a coordenação é feita por um átomo de N do grupo azo e por um átomo de O do grupo fenolato, enquanto em 2 a coordenação ocorre exclusivamente via átomos de O e N da α-iminocetona. Ambos os complexos exibem interações intramoleculares do tipo π-π, que exercem um importante papel na determinação de suas estruturas moleculares, além de também exibirem arranjos supramoleculares governados por ligações de hidrogênio não-clássicas. Em adição, a estrutura de 2 é a primeira relatada na literatura com um novo tipo de ligante, a azo-iminocetona, e também a primeira contendo mercúrio complexado a uma α-iminocetona. This article describes the synthesis and the spectroscopic and structural characterization of two novel azo-containing complexes, cis-bis[4-nitro-2-(4-nitrophenylazo)-phenolate-κN 1 ] bis(piridino-κN)cadmium(II), 1, and cis-bis[2-(4-phenylazo-phenylimino)-2H-acenaphthylen-1-one]dichloromercury(II), 2. In spite of the different metal centres, both complexes show an N,Obidentate complexation to the metal. In 1 the metal coordinates to an azo N and to a phenolate O atom, whereas in 2 the metal binds to an O and an N atom of the α-iminoketone. Both complexes show intramolecular π-π interactions, which play an important role in their molecular structures. In addition they also present non-classical H-bonding, which is crucial to their supramolecular arrangements. Moreover, 2 is the first case in the literature of a complex with a new class of ligand, an azoiminoketone, as well as the first case of an α-iminoketone Hg complex.

Homogeneous {Ti2Ni} Heterotrinuclear Catalyst for Ethylene Polymerization and Copolymerization

“…All complexes reported in this study were obtained as analytically pure solids, confirmed by performing elemental analyses and FTIR spectroscopy. The FTIR spectrum of N1C1 showed a ν(C=N) + ν(C=C) band at 1,586 cm -1 , which was similar to that found in previous studies [29,30]. Additionally, ν(N-H) bands were observed around 3,500 cm -1 , and bands assigned to aromatic C-H vibrations appeared around 3,030 cm -1 .…”

Tunable Electrochemical and Catalytic Features of BIAN- and BIAO-Derived Ruthenium Complexes

“…To our surprise, under identical reaction conditions the use of R-BIAN with R = H (Charts and ) selectively results in [ 2 ]­ClO 4 (blue powder) encompassing [ N -(phenyl)­imino]­acenapthenone (BIAO) via the hydrolysis of one of the imine bonds (CNPh → CO) of BIAN. Complex 2 + represents the first example of a ruthenium-coordinated BIAO ligand; the corresponding mercury, cobalt,copper, and zinc complexes were however reported recently. The representative yellow-colored aqua derivative [Ru II (tpm)­(4-OMe-BIAN)­(H 2 O)]­(ClO 4 ) 2 [ 3a ]­(ClO 4 ) 2 (Chart ) has been prepared from the corresponding chloro derivative ([ 1a ]­ClO 4 ) in the presence of excess AgClO 4 in refluxing 1:3 acetone–water via the Cl/H 2 O exchange process. , …”

Electronic Structure and Multicatalytic Features of Redox-Active Bis(arylimino)acenaphthene (BIAN)-Derived Ruthenium Complexes

“…In this context, the present report deals with the structurally characterized selective ruthenium complexes of BIAN and the corresponding in situ generated partially hydrolyzed [ N -(phenyl)­imino]­acenapthenone , (BIAO, Scheme ) in combination with tridentate 2,2′:6′,2′′-terpyridine/Cl/H 2 O co-ligands (Scheme ). The primary objective of the article is to address the following aspects: Impact of the “R” group on the electron uptake processes of coordinated BIAN in the light of exploring the feasibility of pushing the electron(s) into the antibonding orbitals of naphthalene, i.e., beyond its α-diimine fragment. Application potential of the complexes toward different catalytic processes. The difference between the BIAN and BIAO derived complexes, if any. …”