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Query: UNIPROT:P50583 (
asymmetrical
)
12,197
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The electronic structures of two ferromagnetic polynuclear copper(II) complexes, derived from end-to-end azido ligand and tridentate (
NNN
donor) Schiff base ligand, have been studied using the full-potential linearized augmented plane-wave method based on the density-functional theory. They are [Cu(L1)(micro-1,3-N3)]n(ClO4)n (1) and [Cu(L2)(micro-1,3-N3)]n(ClO4)n (2). The result shows that the spin populations in these two complexes are mainly distributed on the equatorial planes of a square pyramidal that surround the copper(II) ions. There are large and positive spin populations on copper(II) ions, small and positive spin populations on the three nitrogen atoms of tridentate Schiff base ligand, and the two terminal nitrogen atoms of
asymmetrical
end-to-end azido ligand, while weak and negative spin populations on the central nitrogen atoms of
asymmetrical
end-to-end azido ligand. Ferromagnetic coupling through the
asymmetrical
azido ligand in these two complexes has been mainly attributed to the spin delocalization, also with weak spin-polarization effect.
...
PMID:Two ferromagnetic azido-bridged copper(ll) complexes studied by first-principle electronic-structure calculation. 1639 83
Complexes [
NNN
]Ln(AlMe(4))(2) (Ln = Y, La, Nd, Lu) bearing the sterically demanding aryl-substituted triazenido ligand [(Tph)(2)N(3)] (Tph = [2-(2,4,6-iPr(3)C(6)H(2))C(6)H(4)]) can be obtained from homoleptic complexes Ln(AlMe(4))(3) in moderate yields, both via protonolysis with [(Tph)(2)N(3)]H and a salt metathesis reaction pathway utilizing [(Tph)(2)N(3)]K. In the solid state the Y and Lu derivatives are isostructural, with both tetramethylaluminate groups coordinated in an eta(2) fashion, while one of the [AlMe(4)] ligands of the Nd derivative features a distorted eta(2) coordination mode. Due to the high affinity of the triazenido ligand toward the more Lewis-acidic and harder aluminium cation compared to the softer rare-earth metal centres, ligand redistribution is observed in solution and formation of byproduct [(Tph)(2)N(3)]AlMe(2) is prominent. While the monoanionic triazenido ligand coordinates the rare-earth metal centres in an
asymmetrical
syn/anti fashion, it adopts an almost symmetric syn/syn configuration in the aluminium complex. Attempts were also made to produce putative dimethyl complexes {[(Tph)(2)N(3)]LnMe(2)} (Ln = Y, Lu) via cleavage of the aluminate moieties with diethyl ether. Furthermore, the intrinsic redistribution reactions are proposed to affect the performance of complexes [(Tph)(2)N(3)]Ln(AlMe(4))(2) in isoprene polymerization.
...
PMID:Rare-earth metal bis(tetramethylaluminate) complexes supported by a sterically crowded triazenido ligand. 2063 53