Deprotonation Induced Ligand Oxidation in a Ni(II) Complex of a Redox Noninnocent N(1)-(2-Aminophenyl)benzene-1,2-diamine and Its Use in Catalytic Alcohol Oxidation.
Two nickel(II)-complexes, [Ni(II)(H3L)2](ClO4)2 ([1](ClO4)2) and [Ni(II)(HL)2] (2), containing the redox-active tridentate ligand N(1)-(2-aminophenyl)benzene-1,2-diamine (H3L) have been synthesized. Complex [1](ClO4)2 is octahedral containing two neutral H3L ligands in a facial coordination mode, whereas complex 2 is a singlet diradical species with approximately planar configuration at the tetracoordinate metal atom with two pendant NH2 side arms from each of the coordinated ligands. Both complexes are found to be chemically interconvertible; complex [1](2+) gets converted to complex 2 when exposed to base and oxygen via simultaneous deprotonation and oxidation of the coordinated ligands. Molecular and electronic structures of the isolated complexes are scrutinized thoroughly by various spectroscopic techniques, single crystal X-ray crystallography, and density functional theory. The observed dissociation of a ligand arm upon oxidation of the ligand was exploited to bring about catalytic alcohol oxidation using coordinatively saturated complex [1](ClO4)2 as a catalyst precursor. Both the complexes [1](ClO4)2and 2 were tested for catalytic oxidation of both primary and secondary alcohols.
Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur , Botanic Garden, Howrah 711103, India.
Rina
R
Sikari
Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur , Botanic Garden, Howrah 711103, India.
Suman
S
Sinha
Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur , Botanic Garden, Howrah 711103, India.
Upasona
U
Jash
Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur , Botanic Garden, Howrah 711103, India.
Siuli
S
Das
Departamento de Química, CICECO-Instituto de Materiais de Aveiro, Universidade de Aveiro , 3810-193 Aveiro, Portugal.
Paula
P
Brandão
Homogeneous Catalysis Group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam , Science Park 904, 1098 XH Amsterdam, The Netherlands.
Bas
B
de Bruin
Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur , Botanic Garden, Howrah 711103, India.
Nanda D
ND
Paul