| | 1 | Author
| Joachim Heinickea, Attila Dala, Hans-Friedrich Kleinb, Olaf Hetcheb, Ulrich Flörkec, Hans-Jürgen Hauptc | Requires cookie* | | | Title
| Formation of r71-P-(2-Phosphinophenol)Ni(0)(PMe3)3 and Oxidation to cjs/fraws-Bis(2-phosphinophenolato)nickel(II) Complexes  | | | | Abstract
| o-Phosphinophenols 1 (P ^ O H) react with equimolar amounts of Ni(PMe3)4 at low tempera tures to give yellow Ni(0) complexes such as [(HO~P)Ni(PMe3)3] 2a with only P coordination of the P ^ O H ligand. Oxidation of solutions of 1 and Ni(PMe3)4 by dioxygen leads to brown bis(o-phosphinophenolato-P^O)nickel chelate complexes 3a-d. Structure elucidation by NM R is consistent with a m-square planar geometry for 3a-c and a rrans-square planar solution struc ture of the terr-butylphenylphosphino derivative 3d. The geometric isomers were distinguished by different ranges of phosphorus coordination shifts and 3lP-l3C-2 and 3IP-13C-1 coupling | | | |
Reference
| Z. Naturforsch. 54b, 1235—1243 (1999); received May 19 1999 | | | |
Published
| 1999 | | | |
Keywords
| Phosphinophenolate, Nickel, Complexes, Structure Elucidation, Solid State Structures | | | |
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| default:Reihe_B/54/ZNB-1999-54b-1235.pdf | | | | Identifier
| ZNB-1999-54b-1235 | | | | Volume
| 54 | |
| 2 | Author
| Silke Buchler, Franc Meyer, Albrecht Jacobi, Peter Kircher, Laszlo Zsolnai | Requires cookie* | | | Title
| Novel Dinucleating Ligand Systems Containing Two Adjacent Coordination Compartments of the Potential Triamidoamine-Type -Nickel(II) and Cobalt(II) Coordination Chemistry | | | | Abstract
| The preparation of novel dinucleating pyrazolate ligands H5L3 -H5L8 carrying chelating side arms with appending secondary amine functions is reported. Following different synthetic routes, either CH2CF3, C6H2F3 , or CftF? moieties can be introduced as substituents at the termi nal nitrogen atoms. These systems are reminiscent of two coupled coordination compartments of the potential triamidoamine-type. Crystallographic analyses of a series of bimetallic complexes of the CH2CF3-substituted ligand H5L4 with NiCh and C0 CI2 reveal manifold coordination modes in the solid state, resulting from the facile detachment of a single or several N-donor sites from the metal centers. Coordination number sets {4/6} (in H5L4Co2CU) and {5/6} (in H4L4Ni2Cl3, H4L4Co2Cl3 and H5L4Ni2CL) are thus observed. In the non-deprotonated HsL-type systems the remaining protons are found to be scavenged by a pyrazolate-N (in H5L4Ni2CU) or an amine function of a ligand side arm (in H ^ C o iC U). | | | |
Reference
| Z. Naturforsch. 54b, 1295—1306 (1999); received June 18 1999 | | | |
Published
| 1999 | | | |
Keywords
| Dinuclear Complexes, N-Ligands, Nickel, Cobalt, Solid-State Structures | | | |
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| default:Reihe_B/54/ZNB-1999-54b-1295.pdf | | | | Identifier
| ZNB-1999-54b-1295 | | | | Volume
| 54 | |
| 3 | Author
| Robert Ruloff, Thomas Gelbrich, Joachim Sieler, Eberhard Hoyer, Lothar Beyer | Requires cookie* | | | Title
| Strukturen zweier isomerer Gadolinium(III)-Polyaminopolycarboxylate -Argumente für signifikante Unterschiede ihrer ^-NM R-Relaxation Structures of Two Isomeric Gadolinium(III) Polyamino Polycarboxylates -Relation to their Significant Differences in 'H NMR Relaxation | | | | Abstract
| We present preparation and X-ray crystal structures of gadolinium(III) complexes with two isomeric ligands; triethylenetetraminehexaacetic acid, H6ttha, and tris(2-aminoethyl)amine-hexaacetic acid, H6ttaha, respectively. In case of [C(NH2)3]2[Gd(Httha)] • 5 H20 (1) the inner coordination sphere is made up of 9 donor atoms of the ligand and reflects the low efficiency in accelerating 'H NMR relaxation of an aqueous solution. In case of [C(NH2)3]3[Gd(ttaha)] • 3 H20 (2) the coordination number of 9 is realized via 7 donor atoms of the ligand and 2 oxygen atoms of a pending acetate group of the adjacent complex. Luminescence studies in aqueous solution confirm replacement of this acetate group by 2 water molecules. The relaxivity of [Gd(Httaha)]2-is 7.3 ± 0.1 mM ~'s -1 as determined at pH = 7.2, 20 MHz and 40°C. | | | |
Reference
| Z. Naturforsch. 52b, 805—809 (1997); eingegangen am 23. April 1997 | | | |
Published
| 1997 | | | |
Keywords
| Gadolinium(III) Chelates, Solid State Structures, Lanthanoids, 'H NMR Relaxivity, Magnetic Resonance Imaging | | | |
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| default:Reihe_B/52/ZNB-1997-52b-0805.pdf | | | | Identifier
| ZNB-1997-52b-0805 | | | | Volume
| 52 | |
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