Copper(II) complexes of 3,3′-annelated 2,2′-bi[1,8]naphthyridine
1985; Elsevier BV; Volume: 104; Issue: 3 Linguagem: Inglês
10.1016/s0020-1693(00)86772-9
ISSN1873-3255
AutoresMadeleine Draux, Ivan Bernal, François Lefoulon, Randolph P. Thummel,
Tópico(s)Crystal structures of chemical compounds
ResumoFour mononuclear Cu(II) complexes prepared from ligands (L) = 2,2′-bi[1,8]naphthyridine as well as its 3,3′-dimethylene-, 3,3′-trimethylene- and 3,3′-tetramethylene-bridged derivatives were studied by ESR spectroscopy and a single crystal X-ray diffraction analysis was carried out on the dimethylene-bridged compound of composition Cu(L)Cl2(H2O). Crystals are monoclinic, space group P21/n, with a = 8.934(3), b = 11.427(4), c, = 17.382(5) Å and β = 103.65(3)°; V = 1724.5 Å3 and D (cal; z = 4) = 1.68 gm cm−3. Final R and Rw factors were 0.0523 and 0.0497, respectively, for 2260 reflections having I > 3σ(I). The central Cu(II) ion is five-coordinate as a result of its being bound by the two central nitrogens of the heterocyclic ligand, two chlorides and one water in a distorted trigonal bipyramidal arrangement, the nature of whose distortion is principally due to the small bite (77.1°) of the bidentate ligand. Stereochemical features of similar, five-coordinated trigonal bipyramidal Cu(II) compounds are presented, which combined with our results, reveal that for such d9 complexes, the more electronegative substituent prefers the axial position of the trigonal bipyramid. Theoretical predictions made elsewhere are compared against the experimental results described above.
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