Reactivity of Nickel(II) and Copper(II) Complexes of a β-Aminohydrazone Ligand with Pyridine-2-aldehyde: Macrocyclization vs Unprecedented Pyrazole Ring Synthesis via C-C Bond-Forming Reaction.
Summary of "Reactivity of Nickel(II) and Copper(II) Complexes of a β-Aminohydrazone Ligand with Pyridine-2-aldehyde: Macrocyclization vs Unprecedented Pyrazole Ring Synthesis via C-C Bond-Forming Reaction."
The synthesis and characterization of a mononuclear nickel(II) complex [Ni(L(2))](ClO(4))(2) (1) and an analogous mononuclear copper(II) complex [Cu(L(2))](ClO(4))(2) (2) of a 15-membered azamacrocycle (L(2) = 3-(2-pyridyl)-6,8,8,13,13,15-hexamethyl-1,2,4,5,9,12-hexaazacyclopentadeca-5,15-diene) are reported. The macrocyclic ligand is formed during the reaction of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone (L(1)) with pyridine-2-aldehyde (PyCHO) templated by metal ions. The X-ray crystal structure of 1 exhibits a distorted square-pyramidal coordination geometry, where the metal ion sits in the macrocyclic cavity and the pendant pyridine group of L(2) occupies the axial position. While 1 is stable in the presence of an excess of PyCHO, 2 reacts further with copper(II) salt and PyCHO to form a mononuclear copper(I) complex, [Cu(H(2)L(3))](ClO(4))(3) (3). The structure of the complex cation of 3 reveals a distorted tetrahedral coordination geometry at the copper center with a pseudo 2-fold screw axis. A two-dimensional (2D) polymeric copper(II) complex, {[Cu(2)(L(4))(2)](ClO(4))(2)}(n) (4) is obtained by reacting complex 2 (or [Ni(L(1))](ClO(4))(2)) with copper(II) perchlorate and pyridine-2-aldehyde in a methanol-water solvent mixture. Complex 4 is also obtained by treating 3 with copper(II) perchlorate and pyridine-2-aldehyde in the presence of a base. The X-ray structural analysis of 4 confirms the formation of a pyrazolate bridged dimeric copper(II) complex. The extended structure in the solid state of 4 revealed the formation of a 2D coordination polymer with the dimeric core as the repeating unit. The ligand (HL(4)) in 4 is a 3,4,5-trisubstituted pyrazole ring formed in situ via C-C bond formation and represents an unprecedented transformation reaction.
Affiliation
Department of Inorganic Chemistry, Indian Association for the Cultivation of Science , 2A & 2B Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
Journal Details
This article was published in the following journal.
Name: Inorganic chemistry
ISSN: 1520-510X
Pages: 8012-9
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21805958
- DOI: http://dx.doi.org/10.1021/ic200261j
Medical and Biotech [MESH] Definitions
Copper Radioisotopes
Unstable isotopes of copper that decay or disintegrate emitting radiation. Cu atoms with atomic weights 58-62, 64, and 66-68 are radioactive copper isotopes.
Chromium Alloys
Specific alloys not less than 85% chromium and nickel or cobalt, with traces of either nickel or cobalt, molybdenum, and other substances. They are used in partial dentures, orthopedic implants, etc.
Menkes Kinky Hair Syndrome
An inherited disorder of copper metabolism transmitted as an X-linked trait and characterized by the infantile onset of HYPOTHERMIA, feeding difficulties, hypotonia, SEIZURES, bony deformities, pili torti (twisted hair), and severely impaired intellectual development. Defective copper transport across plasma and endoplasmic reticulum membranes results in copper being unavailable for the synthesis of several copper containing enzymes, including PROTEIN-LYSINE 6-OXIDASE; CERULOPLASMIN; and SUPEROXIDE DISMUTASE. Pathologic changes include defects in arterial elastin, neuronal loss, and gliosis. (From Menkes, Textbook of Child Neurology, 5th ed, p125)
Copper Sulfate
A sulfate salt of copper. It is a potent emetic and is used as an antidote for poisoning by phosphorus. It also can be used to prevent the growth of algae.
Hepatolenticular Degeneration
A rare autosomal recessive disease characterized by the deposition of copper in the BRAIN; LIVER; CORNEA; and other organs. It is caused by defects in the ATP7B gene encoding copper-transporting ATPase 2 (EC 3.6.3.4), also known as the Wilson disease protein. The overload of copper inevitably leads to progressive liver and neurological dysfunction such as LIVER CIRRHOSIS; TREMOR; ATAXIA and intellectual deterioration. Hepatic dysfunction may precede neurologic dysfunction by several years.
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