16 research outputs found
[5,10,15,20-Tetrakis(4-chlorophenyl)porphyrinato]bis(tributylphosphine)cobalt(III) perchlorate
In the molecule of the title compound, [Co(C44H24Cl4N4){(C4H9)3P}2]ClO4, the CoIII centre has a slightly distorted octahedral geometry and is coordinated by four N atoms of the tetrapyrrolic ring in the equatorial positions and two phosphine ligands in the axial positions. The dihedral angles between meso-substituted chlorophenyl rings and the basic tetrapyrrolic ring are 82.66 (9), 82.16 (7), 83.97 (11) and 76.87 (8)°. In one of the phosphine ligands, the two terminal methyl groups are disordered over two positions with refined site-occupancy ratios of 0.70 (7):0.30 (7) and 0.66 (2):0.34 (2). In the crystal structure, molecules are linked together along the a axis by intermolecular C—H⋯Cl interactions. The crystal structure is further stabilized by intramolecular C—H⋯O and C—H⋯N interactions and intermolecular C—H⋯O and C—H⋯π interactions
Tetradentate schiff base ligands of 3,4- diaminobenzophenone: Synthesis, characterization and thermodynamics of complex formation with Ni(II), Cu(II) and Zn(II) metal ions
Some new symmetrical diimino tetradentate Schiff base ligands were synthesized by the reaction of 3,4-diaminobenzophenone with salicylaldehyde derivatives, such as [3,4-bis(((2-hydroxy-4-methoxyphenyl)methylene)amino)phenyl]phenylmethanone (L1), [3,4-bis(((2-hydroxy-5-methoxyphenyl)methylene)amino)phenyl]phenylmethanone (L2), [3,4-bis(((5-bromo-2-hydroxyphenyl)methylene)amino)phenyl]phenylmethanone (L3) and [3,4-bis(((2-hydroxy-5-nitrophenyl)methylene)amino)phenyl]phenylmethanone (L4). Additionally, a tetradentate Schiff base ligand [3,4-bis(((2-hydroxy-3-methoxyphenyl)methylene)amino)phenyl]phenylmethanone (L5) was synthesized. All the Schiff bases and their Ni(II), Cu(II) and Zn(II) complexes were characterized using elemental analysis and infrared, electronic, mass and 1H-NMR spectroscopy. The formation constants of the complexes were measured using UV–Vis spectroscopic titration at constant ionic strength 0.10 M (NaClO4), at 25 °C in dimethylformamide (DMF) as solvent
Symmetrical and Unsymmetrical Schiff Bases Derived from 3,4-Diaminobenzophenone: Synthesis and Thermodynamics of Five Coordinated Tertiaryphosphine Cobalt(III) Complexes
Some new cobalt(III) complexes described as [Co(Chel)(PBu<sub>3</sub>)]ClO<sub>4</sub> × H<sub>2</sub>O where (Chel) is the deprotonated form of a series of symmetric and unsymmetrical Schiff base ligands containing 3,4-diaminobenzophenone (3,4-DABP) and substituted salicylaldehyde moieties and [Co(Chel)(PMePh<sub>2</sub>)]ClO<sub>4</sub> × H<sub>2</sub>O where (Chel) is [N’-(5-BrSalDABP)] were synthesized and characterized by 1H NMR, IR, UV–Vis spectroscopy, and elemental analysis. The formation constants and the thermodynamic parameters were determined spectrophotometrically for 1: 1 adduct formation of the new complexes as acceptor with some aliphatic amines such as benzylamine, n-butylamine, sec-butylamine and tert-butylamine as donors in DMSO solvent in constant ionic strength (I = 0.1 M NaClO4). The formation constants change according to the following trend due to the steric and the electronic factors of the cobalt(III) complexes: N’-5-OMe > N’-5-H > N’-5-Br > N’-5-Cl; N,N’-3-OMe > N,N’-4-Ome.
The trend of the formation constants of cobalt(III) Schiff base complexes toward a given donor according to the axial ligand is as follow: PBu3 > PMePh<sub>2</sub>. Also, the following binding trend of the donors toward a given cobalt(III) Schiff base complex is obtained: benzylamine >
<i>n</i>-butylamine > <i>sec</i>-butylamine > <i>tert</i>-butylamine.
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