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Tri- and Tetranuclear Nickel(II) Inverse Metallacrown Complexes Involving Oximato Oxygen Linkers: Role of the Guest Anion (Oxo versus Alkoxo) in Controlling the Size of the Ring Topology
- Source :
- Inorganic Chemistry, Inorganic Chemistry, American Chemical Society, 2010, 49, pp. 9026-9035. ⟨10.1021/ic101273y⟩
- Publication Year :
- 2010
- Publisher :
- HAL CCSD, 2010.
-
Abstract
- 10 pages; International audience; A trinuclear oximato complex, [(NiHL1)3( μ3-O)]ClO4 (1), with inverse metallacrown 9-MC-3 topology has been synthesized using a Schiff-base ligand (H2L1) formed by condensation of ethanolamine (Hea) and diacetylmonoxime (Hdamo). The diamagnetic compound has been characterized by electrospray ionization mass spectrometry as well as by single-crystal X-ray diffraction analysis. In the solid state, the alcoholic OH group in this molecule stays away from coordination. Surprisingly in a similar chemical reaction, when intact Hea and Hdamo have been used as ligands instead of their Schiff-base forms, the product obtained is a 12-MC-4-type metallacrown, (Et3NH)[Ni4(damo)4(Hea)2(ea)2](ClO4)3 (2), with a larger cavity size needed to accommodate a pair of hydrogen-bonded (O-H3 3 3 O)- anions. Unlike in 1, the alcoholic OH groups in 2 take part in metal coordination. Compound 2 on being refluxed with lithium hydroxide inmethanol is converted to 1 in almost quantitative yield. This appears to be a novel reaction type, leading to contraction of a metallacrown ring size. A family of 12-MC-4 Ni4 metallacrowns in inverse topology, viz., [Ni4(damo)4(H2dea)2(Hdea)2](ClO4)2 3 2H2O (3), [Ni4(dpko)4(Hea)2(ea)2](ClO4)2 3 4H2O (4), and [Ni4(mpko)4(Hmea)2(mea)2](ClO4)2 (5), have been synthesized following a methodology similar to that adopted for 2, using different combinations of free oximes [viz., dipyridylketonoxime (Hdpko) and methylpyridylketonoxime (Hmpko)] and amin alcohols [viz., diethanolamine (H2dea), and N-methylethanolamine (Hmea)]. Crystal and molecular structures of 3-5 have been reported, each involving either a quasi (in 3) or a perfect (in 4 and 5) square plane (S4 symmetry) with four octahedral Ni centers occupying the corners, and serve as a backbone of puckered metallacrown rings that accommodate a pair of hydrogenbonded (O-H3 3 3 O)- anions. Antiferromagnetic interactions within the [Ni4] core [J/kB ≈ -20 to -27 K based on the following spin Hamiltonian: H=-2J(S1 3 S2þ S2 3 S3þ S3 3 S4þ S4 3 S1)] lead to an ST=0 ground state for these complexes. Introduction Metallacrowns are a type of metallacycle that can be considered as inorganic analogues of crown ethers because of the similarities they have both in structure and in function.1 These compounds usually have a combination of a transition-metal ion and a heteroatom (usually nitrogen)
- Subjects :
- Anions
Models, Molecular
Stereochemistry
Electrospray ionization
chemistry.chemical_element
[CHIM.INOR]Chemical Sciences/Inorganic chemistry
Crystallography, X-Ray
010402 general chemistry
01 natural sciences
Chemical reaction
Lithium hydroxide
Inorganic Chemistry
chemistry.chemical_compound
Metallacrown Complexes Involving Oximato
Ethanolamine
Nickel
Organometallic Compounds
Molecule
Particle Size
Physical and Theoretical Chemistry
Metallacrown
Molecular Structure
010405 organic chemistry
Ligand
Tri and Tetranuclear Nickel
0104 chemical sciences
Oxygen
Crystallography
chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 00201669 and 1520510X
- Database :
- OpenAIRE
- Journal :
- Inorganic Chemistry, Inorganic Chemistry, American Chemical Society, 2010, 49, pp. 9026-9035. ⟨10.1021/ic101273y⟩
- Accession number :
- edsair.doi.dedup.....6d03cb264faa1e7032920885a74b2da7