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Details van artikel 67 van 116 gevonden artikelen
| Titel: |
PREPARATION, STRUCTURE AND PROPERTIES OF A COPPER(II) COMPLEX WITH A NEW TRIPODAL TETRADENTATE LIGAND, BIS{(6-PIVALOYLAMINO-2-PYRIDYL)METHYL}{(5-CARBOXY-2-PYRIDYL)METHYL}AMINE (BPCA), AND REACTION OF ITS Cu(I) COMPLEX WITH DIOXYGEN |
| Auteur: |
Harata, Manabu Jitsukawa, Koichiro Masuda, Hideki Einaga, Hisahiko |
| Verschenen in: |
Journal of coordination chemistry |
| Paginering: | Jaargang 44 (1998) nr. 3-4 pagina's 311-324 |
| Jaar: |
1998-07-01 |
| Inhoud: |
A copper complex with a new tripodal tetradentate ligand, bis{(6-pivaloylamino-2-pyridyl)-methyl}{(5-carboxyl-2-pyridyl)methyl}amine (BPCA), has been prepared as a model metal centre of copper enzymes that react with dioxygen, the behaviour of which in solution has been examined on the basis of absorption and ESR spectra. Addition of NaN3 to an H2O/CH3OH solution containing Cu(ClO4)2 6H2O-BPCA with 1:1 molar ratio has afforded the complex [Cu-(bpca)(N3)]ClO4. It crystallizes in the monoclinic space group P2/a, a= 17.478(3), b= 9.773(1), c = 22.388(5) Å, β = 102.92(2)°, Z = 4. The crystal structure reveals that the coordination around the central metal ion forms a trigonal bipyramid with three pyridine nitrogen atoms of BPCA (Cu-N(2) = 2.01(2), Cu-N(3) = 2.09(1) and Cu-N(4) = 2.22(1) Å), in the trigonal plane and with a tertiary amino nitrogen atom of BPCA (Cu-N(l)= 1.99(1)Å) and an azide anion (Cu-N(7) = 1.96(2) Å) in axial positions. The azide ion is coordinated in an end-on configuration, the coordinating nitrogen of which forms hydrogen bonds with two amide NH groups of BPCA; the terminal nitrogen is weakly bound with the carboxyl group of BPCA by hydrogen bonds through a water molecule. Cyclic voltammetry of an acetonitrile solution containing Cu(ClO4)2 6H2O-BPCA-KCl with 1:1:1 molar ratio exhibits reversible one-electron redox behaviour with E1/2 = + 0.24 V vs NHE, indicating that the BPCA ligand can stabilize the lower oxidation state of copper. Reaction of [Cu1(bpca)]ClO4 with dioxygen in methanol or propionitrile at —78°C gives marked absorption changes which suggest the formation of a Cu-O2 complex. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 67 van 116 gevonden artikelen
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