Synthesis, characterization, and single crystal X-ray structures of [[Co.sup.III](acacen)[(thioacetamide).sub.2]]Cl[O.sub.4] and [[Co.sup.III][((BA).sub.2]en)[(thioacetamide).sub.2]] [PF.sub.6]--Solvatochromic properties of [[Co.sup.III](acacen)[(thioacetamide).sub.2]]Cl[O.sub.4]

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From: Canadian Journal of Chemistry(Vol. 83, Issue 12)
Publisher: NRC Research Press
Document Type: Article
Length: 4,684 words
Lexile Measure: 1670L

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Abstract :

The trans-[[Co.sup.III](acacen)[(ta).sub.2]]Cl[O.sub.4] (1) and trans-[[Co.sup.III][((BA).sub.2]en)[(ta).sub.2]][PF.sub.6] (2) complexes, where [H.sub.2]acacen = bis(acetylacetone)ethylenediimine, [H.sub.2][(BA).sub.2]en = bis(benzoylacetone)ethylenediimine, and ta = thioacetamide, have been synthesized by a solid-state method, and characterized by elemental analyses, IR, UV-vis, and [sup.1]H NMR spectroscopy. The crystal and molecular structures of 1 and 2 were determined by X-ray crystallography. Both compounds crystallize in the monoclinic space group P2/n. The Cl[O.sub.4] and [PF.sub.6] ions are both disordered, Cl[O.sub.4] on a twofold axis in 1 and [PF.sub.6] on an inversion center in 2. Also bridging N-[CH.sub.2]-[CH.sub.2]-N is disordered in both compounds. The octahedral coordination of Co(III) is slightly distorted in both cases. The thioacetamide ligands are S-bonded and occupy the axial position. The IR, UV-vis, and [sup.1]H NMR spectra of the two complexes and their solvatochromic properties are also discussed. The longest wavelength absorption that appears at 517 nm for 1 and at 528 nm for 2 in chloroform is solvent dependent, and is assigned as a metal-mediated ligand-to-ligand charge transfer (LLCT). Key words: solid-state synthesis, thioactamide, Co(III) (Schiff base), crystal structure, solvatochromism, metal-mediated LLCT. Utilisant une methode en phase solide, on a synthetise les complexes trans-[[Co.sup.III](acacen)[(ta).sub.2]]Cl[O.sub.4] (1) et trans-[Co.sup.III][((BA).sub.2]en)[(ta).sub.2]][PF.sub.6] (2) dans lesquels [H.sub.2] acacen = bis(acetylacetone)ethylenediimine, [H.sub.2][(BA).sub.2]en = bis(benzoy-lacetone)ethylenediimine et ta = thioacetamide, et on les a caracterises par le biais d'analyses elementaires, de spectroscopies IR, UV-vis et RMN du [sup.1.]H. On a determine les structures cristallines et moleculaires des composes 1 et 2 par diffraction des rayons X. Les deux composes cristallisent dans le groupe d'espace monoclinique P2/n. Les ions Cl[O.sub.4] et [PF.sub.6] sont tous les deux desordonnes, le Cl[O.sub.4] sur un axe binaire dans 1 et le [PF.sub.6] sur un centre d'inversion dans 2. Le chainon N-[CH.sub.2]-[CH.sub.2]-N qui agit comme pont est aussi desordonne dans les deux composes. La coordination tetraedrique du Co(III) est legerement deformee dans les deux cas. Les ligands thioacetamides sont lies par le soufre et occupent une position axiale. On discute aussi des spectres IR, UV-vis et RMN du [sup.1]H des deux complexes et de leurs proprietes solvatochromiques. La bande d'absorption de plus grande longueur d'onde qui apparah, dans le chloroforme, a 517 nm pour le compose 1 et a 528 nm pour le compose 2, depend du solvant et elle est attribuee h un transfert de charge de ligand a ligand aidee par le metal. Mots cles : synthese a l'etat solide, thioacetamide, base de Shiff du Co(III), structure cristalline, solvatochromie, transfert de charge de ligand a ligand aidee par le metal. [Traduit par la Redaction]

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Gale Document Number: GALE|A145680548