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| Ni(C2H8N2)2NO2ClO4 | |
|---|---|
| Name | bis(ethylenediamine)nitronickel(II) perchlorate |
| Chemical formula | Ni(C2H8N2)2NO2ClO4 |
| Molar mass | 307.72 g·mol−1 (for cation + anion components per unit) |
| Appearance | turquoise/blue crystalline solid |
| Solubility | soluble in water and polar solvents |
Ni(C2H8N2)2NO2ClO4
Ni(C2H8N2)2NO2ClO4 is a coordination compound comprising a nickel(II) center coordinated by two ethylenediamine ligands and a nitro ligand, paired with a perchlorate counterion. This complex is notable in coordination chemistry and solid-state studies for its distinct ligand field, magnetic behavior, and sensitivity of its perchlorate-containing salts. The compound has been investigated in contexts overlapping inorganic synthesis, crystallography, and spectroscopy.
The compound is formally described as bis(ethylenediamine)nitronickel(II) perchlorate, where ethylenediamine corresponds to the common ligand often abbreviated en. Alternate systematic names include IUPAC-style descriptors referencing nickel(II) coordination by two bidentate amines and a monodentate nitro ligand, with perchlorate as the anion. Related entries in the literature often cross-reference classical coordination complexes such as Werner complexes and canonical nickel amine salts characterized by early 20th-century work of Alfred Werner and later systematic compilations by authors associated with International Union of Pure and Applied Chemistry nomenclature. The perchlorate anion evokes attention due to associations with energetic salts historically discussed in contexts like Perchlorate contamination and regulatory treatment by agencies such as Environmental Protection Agency.
Typical preparations employ nickel(II) salts such as nickel(II) chloride or nickel(II) sulfate reacted with ethylenediamine in aqueous or mixed aqueous–organic media under inert or ambient atmosphere, followed by introduction of nitrite or nitric acid sources to install the nitro ligand and subsequent metathesis with perchlorate salts (e.g., sodium perchlorate) to precipitate the perchlorate salt. Synthetic protocols reflect methodologies developed in classical coordination chemistry laboratories at institutions like University of Oxford and Massachusetts Institute of Technology for amine coordination complexes. Controlled crystallization techniques—slow evaporation, vapor diffusion, or cooling—are often used, drawing on crystallographers’ practices associated with groups at Cavendish Laboratory and facilities such as synchrotron beamlines at Diamond Light Source for high-quality crystal growth.
The coordination sphere around nickel(II) is typically six-coordinate with two chelating ethylenediamine ligands (en) forming four Ni–N bonds and one nitro group coordinating as a monodentate NO2 ligand to occupy the fifth position; the sixth site can be occupied by solvent or be influenced by crystal packing, giving rise to pseudo-octahedral geometries common to many nickel(II) complexes described in monographs by authors at California Institute of Technology and University of Cambridge. Bonding involves sigma donation from the amine lone pairs and pi-backbonding influences modulated by the nitro ligand, comparable to ligand field descriptions in texts associated with Fritz Haber Institute-style theoretical treatments. Solid-state arrangements often show packing motifs influenced by perchlorate anions, invoking noncovalent interactions reminiscent of studies from groups at Max Planck Society.
Solid samples display colored crystalline habits, often turquoise to blue, reflecting d–d transitions characteristic of high-spin or intermediate-field nickel(II) centers documented in spectroscopy catalogs from institutions like National Institute of Standards and Technology. The salt is usually soluble in polar solvents (water, methanol) and may exhibit thermal sensitivity because of the perchlorate component, a property that has been considered in safety guidance from organizations such as Occupational Safety and Health Administration. Magnetic susceptibility measurements often reveal paramagnetic behavior consistent with two unpaired electrons for octahedral nickel(II), a feature paralleling entries in magnetic data compilations maintained by research groups at Los Alamos National Laboratory.
Characterization routinely employs single-crystal X-ray diffraction, infrared spectroscopy, electronic (UV–Vis) spectroscopy, and magnetic susceptibility. X-ray crystallography provides definitive atomic positions and coordination geometry; facilities at Argonne National Laboratory or university crystallography centers have produced comparable structural determinations for related complexes. Infrared spectra show diagnostic bands for coordinated nitro groups and perchlorate anions, and UV–Vis spectra present ligand-field bands analogous to spectra cataloged by researchers from University of California, Berkeley. Electron paramagnetic resonance and NMR (paramagnetically shifted) studies further elucidate electronic environment, following analytical traditions from Royal Society of Chemistry publications.
Chemically, the complex can undergo ligand substitution on the nitro site or displacement of ethylenediamine under stronger chelating conditions, echoing reactivity patterns reported by coordination chemists at ETH Zurich and University of Tokyo. Redox behavior may be accessed electrochemically; comparisons are often drawn to nickel(II)/nickel(III) couples studied at electrochemistry laboratories at Imperial College London and Stanford University. The perchlorate counterion is generally non-coordinating but influences solubility and crystallization; its reactivity considerations mirror those in studies of energetic materials and ion pairing overseen by agencies such as Department of Energy.
While not a mainstream industrial material, the compound serves as a model system in academic studies of ligand field theory, chelation, and solid-state packing effects; such model complexes underpin pedagogical examples used at institutions like Harvard University and Yale University. Investigations contribute to broader efforts in fields connected to catalysis, materials science, and magnetic materials, echoing cross-disciplinary research themes pursued at centers like Lawrence Berkeley National Laboratory and collaborative programs funded by organizations such as National Science Foundation. Its utility lies principally in fundamental research, crystallographic benchmarking, and spectroscopic calibration.
Category:Nickel complexes Category:Coordination compounds Category:Perchlorates