Synthesis, characterization, and thermodynamics of tertiary phosphine cobalt(III) Schiff-base complexes

Abstract

Co(5-nitroSalen)(PBu 3 )]ClO 4 ·H 2 O and [Co(Salpd)(PBu 3 )]ClO 4 ·H 2 O were synthesized and characterized. The stability constants and the thermodynamic parameters were measured spectrophotometrically for 1:1 adduct formation of [CoL(PBu 3 )]ClO 4 ·H 2 O, (L = Salen, 5-nitroSalen, Salpd), and [Co(Salen)(PMe 2 Ph)]ClO 4 ·H 2 O as acceptors with P(OR) 3 (R = Me, Et, i-Pr) as donors, in acetonitrile solvent and in constant ionic strength (I = 0.01 M) and at various temperatures. The trend of the reactivity of cobalt(III) Schiff-base complexes with PBu 3 axial ligand toward a given donor is as follows: 5-nitroSalen > Salen > Salpd. Also, the following reactivity trend of the donors toward a given cobalt(III) Schiff-base complex is in the operation: P(O-i-Pr) 3 > P(OEt) 3 > P(OMe) 3 . Résumé : On a effectué la synthèse et on a caractérisé les complexes suivants: [Co(5-nitroSalen)(PBu 3 )]ClO 4 ·H 2 O et [Co(Salpd)(PBu 3 )]ClO 4 ·H 2 O. Faisant appel à des méthodes spectrophotométriques, on a mesuré les constantes de stabilité et les paramètres thermodynamiques pour la formation d'adduits 1:1 entre les complexes accepteurs [CoL(PBu) 3 ]ClO 4 ·H 2 O dans lesquels L = Salen, 5-nitroSalen et Salpd et [Co(Salen)(PMe 3 Ph)]ClO 4 ·H 2 O et les P(OR) 3 (dans lesquels R = Me, Et, i-Pr) comme accepteurs, dans l'acétonitrile comme solvant, à force ionique constante (I = 0,01 M) et à diverses températures. La tendance de la réactivité des complexes des bases de Schiff du cobalt(III) avec le ligand PBu 3 axial est donnée par la séquence suivante: 5-nitroSalen > Salen > Salpd.Du côté des donneurs vis-à-vis d'un complexe donné d'une base de Schiff du cobalt(III), la tendance est exprimée par la séquence suivante: P(O-i-Pr) 3 > P(OEt) 3 > P(OMe) 3 .

Polymeric Membrane and Solid Contact Electrodes Based on Schiff Base Complexes of Co(III) for Potentiometric Determination of Perchlorate Ions

“…The Schiff base complexes of cobalt(III) were synthesized and purified according to the previously reported procedures. 27,28 Electrode preparation. The general procedure to prepare the PVC membranes was to dissolve varying amount of ionophore, additive HTAB and powdered high molecular weight PVC in 5 mL THF.…”

Thermodynamic study of the interaction of Co(II)-Schiff base complexes with phosphines

“…It has been suggested [24] that when cobalt ion is chelated in a macrocycle having delocalized electronic structure, the Schiff base and the axial ligands on the equilibrium constants were investigated in our laboratory, previously [16][17][18][19][20][21].…”

“…To pursue our previous work [16][17][18][19][20][21], in this paper we report the results of the thermodynamic study of the interaction of some four-coordinate Co(II)-Schiff base complexes with tributylphosphine (PBu 3 ) and diphenylmethylphosphine (PPh 2 Me) in dichloromethane.…”

Metallation of tetradentate N2O2 Schiff base with Mn(II), Co(II), Cu(II) and Zn(II): synthesis, characterization and formation constants measurement

“…In view of recent interest in the energetic of the metal ligand bonding in metal chelates involving N, O donor ligand, we tried to study Schiff base complexes derived from N,N'-bridged tetradentate ligands involving N 2 O 2 donor atoms [21][22][23][24][25][26][27][28]. There are some title Schiff bases and Cu(II) and Mn(III) complexes, which were previously synthesized [29][30][31][32][33] but comprehensive studies on complexation not achieved.…”