کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1311847 | 975360 | 2005 | 12 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Polynuclear nickel (II) and copper (II) complexes of hexaazamacrocycles incorporating pairs of diethylenetriamine subunits separated by aromatic spacers Polynuclear nickel (II) and copper (II) complexes of hexaazamacrocycles incorporating pairs of diethylenetriamine subunits separated by aromatic spacers](/preview/png/1311847.png)
A series of Ni(II) and Cu(II) complexes of the hexaaza macrocycles, 3,6,9,17,20,23-hexaazatricyclo[23.3.1.111,15]triaconta-1(29),11(30),12,14,25,27-hexaene (L1) and 3,6,9,16,19,22-hexaazatricyclo[22.2.2.211,14]triaconta-1(26),11(29),12,14(30),24(28),25-hexaene (L2), have been prepared and the crystal structures determined for [Ni2L1(O2CCH3)2(H2O)2](ClO4)2 (1), [Ni2L2(DMF)6](ClO4)4 · 2H2O (2), {[Cu2L2Br(O2CCH3)](ClO4)2}n (3), [Cu2L2(μ-CO3)(H2O)2]2(ClO4)4 · 8H2O (4), [Cu2L2(O2CCH3)2](BF4)2 (5), and [Cu2L1(μ-imidazolate)Br]2Br4 · 6H2O (6). In these complexes, two metal centers are bound per ligand; in 1 and 3–6, the N3 subunits of L1 or L2 coordinate meridionally to the metal centers, whilst in 2, each N3 subunit in L2 adopts a facial mode of coordination. The binuclear cations in 1 and 2 have chair-like conformations, with the distorted octahedral Ni(II) coordination spheres completed by terminal water and a bidentate acetate ligand in 1 and three DMF ligands in 2. The Cu(II) centers in 3–6 generally reside in square planar environments, although a weakly binding ligand enters the coordination sphere in some cases, generating a distorted square pyramidal geometry. The binuclear [Cu2L2]4+ units in 3, 4 and 5 adopt similar bowl-shaped conformations, stabilized by H-bonding interactions between pairs of amine groups from L2 and a perchlorate or tetrafluoroborate anion. In 3, the binuclear units are linked through acetate groups, bridging in a syn-anti fashion, to produce a zig-zag polymeric chain structure, whilst 4 incorporates a tetrameric cation consisting of two binuclear units linked via a pair of carbonate bridges. Compound 6 features an imidazolate bridge between the two Cu(II) centers bound by L1. Pairs of [Cu2L1(μ-imidazolate)]3+ units are then weakly linked through a pair of bromide anions.
Macrocyclic ligands incorporating two diethylenetriamine chelating subunits, separated by m-xylyl and p-xylyl spacers, form binuclear Ni(II) and Cu(II) complexes, which in some cases assemble into species with higher nuclearity.Figure optionsDownload as PowerPoint slide
Journal: Inorganica Chimica Acta - Volume 358, Issue 13, 1 September 2005, Pages 3983–3994