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  • 1
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure Reactivity Correlations in Coordinatively Unsaturated Metal Chelate Complexes. IX. Comparative Investigations on the Axial Ligation of Tricyclic and Macrocyclic Iron Chelate Complexes of Schiff BasesThe addition of axial bases at the iron chelates 1a and 2b has been compared by isolation of stable adducts with methanol, pyridine, and imidazole. 1a forms octahedral high-spin adducts whereas 2b gives mainly pentacoordinated intermediate-spin and octahedral low-spin derivatives. The iodo-iron(III) derivatives are high-spin too in the case 1a and intermediate-spin in the case 2b. The carbonyl substituted macrocycles 2 are closer related to iron porphyrines than the analogous chelates 3 and 4.
    Notes: Die Addition axialer Basen an die Eisenchelate 1a und 2b wurde durch Isolierung stabiler Addukte mit Methanol, Pyridin und Imidazol verglichen. 1a bildet oktaedrische high-spin-Addukte, während 2b hauptsächlich pentakoordinierte intermediate-spin-und oktaedrische low-spin-Derivate ergibt. Auch die Iodoeisen(III)-Derivate sind bei 1a high-spin- und bei 2b intermediate-spin-Komplexe. Die carbonylsubstituierten Makrocyclen 2 sind den Eisenporphyrinen enger verwandt als die analogen Chelate 3 und 4.
    Additional Material: 2 Ill.
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  • 2
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of New Unsymmetrically Substituted N-(2-Aminophenyl)-azomethines of β-Ketoaldehydes via Template Condensation with Nickel(II) as Potential Precursors of Unsymmetrically Substituted Macrocyclic ComplexesThe synthesis of new unsymmetrically substituted nickel(II) complexes of type 4 is described. These complexes arises via template condensation of the unsymmetrically substituted tridentate amino-azomethines 3, whereas only the amino group of the less reactive and the carbonyl group of the more reactive aminoazomethine react with each other. Diamagnetic square-planar nickel(II) complexes with a [N3O] donor set and an uncoordinated amino group are formed. The complexes are precursors of carbonyl-substituted macrocyclic chelates. Further condensations of the amino group with e. g. dialdehydes or diketons are possible. All the new complexes are characterized by visible and 1H and 13C n.m.r. spectra as well. The influence of several peripheral substituents on the distribution of the electron density of the ligand is investigated. Strong O…H bonds forms a 6-membered ring between the uncoordinated amino group, the coordinated carbonyl group and the substituents at the R3 position.
    Notes: Die Synthese neuer unsymmetrisch substituierter Nickel(II)-Komplexe des Typs 4 wird beschrieben. Die Komplexe entstehen durch Template-Kondensation der unterschiedlich substituierten dreizähnigen Aminoazomethine 3, wobei nur die Aminogruppe des weniger reaktiven und die Carbonylgruppe des reaktiveren Aminoazomethins miteinander reagieren. Es entstehen diamagnetische planare Nickel(II)-Komplexe mit [N3O]-Koordination und einer freien Aminogruppe. Die Komplexe stellen Vorstufen für carbonylsubstituierte makrocyclische Chelate dar. Die freie Aminogruppe ist weiteren Kondensationsreaktionen, z. B. mit Dialdehyden oder Diketonen, zugänglich. Alle neuen Komplexe werden durch sichtbare sowie 1H- und 13C-NMR-Spektren ausführlich charakterisiert. Der Einfluß der verschiedenen peripheren Substituenten auf die Verteilung der Elektronendichte im Liganden wird untersucht. Zwischen der freien Aminogruppe des Liganden, der koordinierten Carbonylgruppe und dem Substituenten R3 bildet sich über starke H-Brücken ein Sechsring aus.
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  • 3
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure Reactivity Correlations in Coordinatively Unsaturated Chelate Complexes. IV. Reaction of Dioxygen with Cobalt(II) Chelates of Tridentate Di-anionic Schiff Base LigandsThe high-spin cobalt(II) chelates 3 form with pyridine isolable adducts which are also high-spin complexes. In the case 3 b a low-spin mono-adduct is indicated by ESR spectroscopy, which is changed time-dependently into a stable quadratic-pyramidal form. With 1, 10-phenanthroline 3 b forms a low-spin mono-adduct. The spectrophotometric titration of 3 d with pyridine indicates an equilibrium A + 2 Py ⇌ APy2 (β2 = 0,36 M-2) where A represents probably the tetrameric form of 3 d. In pyridine, 3 a, 3 b, and 3 d react with O2 in an 1:1 ratio; 3 c binds O2 in the ratio 2:1. The formation of superoxo complexes is indicated by ESR spectroscopy for the complexes 3 a, 3 b, and 3 d. 3 b reacts with O2 in piperidine to give the free superoxide ion. In n-butylamine a species is formed which seems to be an ion pair with direct interactions between the free O2- ion and the coordinated amine nitrogen.
    Notes: Die high-spin-Cobalt(II)-Chelate 3 bilden mit Pyridin isolierbare Addukte, die ebenfalls zum high-spin-Typ gehören. Bei 3 b ist ESR-spektroskopisch ein low-spin-Addukt nachweisbar, das sich zeitabhängig in eine stabile quadratisch-pyramidale Form umwandelt. Mit 1,10-Phenanthrolin bildet 3 b ein low-spin-Monoaddukt. Die spektrophotometrische Titration von 3 d mit Pyridin zeigt ein Gleichgewicht A + 2 Py ⇌ APy2 an (β2 = 0,36 M-2), worin A vermutlich das Tetramere von 3 d ist. In Pyridin reagieren 3 a, 3 b und 3 d im Verhältnis 1:1, 3 c im Verhältnis 2:1 mit O2. ESR-spektroskopisch sind bei 3 a, 3 b und 3 d Superoxokomplexe nachweisbar. 3 b bildet mit O2 in Piperidin freies Superoxid und in n-Butylamin eine Spezies, deren ESR-Spektrum auf ein Ionenpaar mit direkter Wechselwirkung zwischen freiem O2- und koordiniertem Aminstickstoff hindeutet.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 589 (1990), S. 101-114 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Structure Studies on Derivatives of the Nickel Complex Ni(ONO) (ONO2- = Dianion of a Tridentate Schiff Base)The thermodynamically stable form of the solvent free, formally tri-coordinate complex Ni(ONO) (ONO2- = dianion of N-(2-hydroxyphenyl)-2-ethoxycarbonyl-3-ox(o-butene(1) amine(1)) as well as the mono adducts Ni(ONO)X with X = ammonia and X = diphenyl thiourea (DPT) have been characterized by X-ray structure analysis. In all cases the central atom is coordinated in a square-planar fashion, only for the adduct Ni(ONO)(DPT) a pyramidal distortion is observed which is due to the formation of hydrogen bonds. The solvent free form is a dimer [Ni(ONO)]2, and represents one of the few examples of dinuclear nickel complexes with a planar [NO3] coordination. The phenolic O-atoms act as bridging ligands. Due to their reduced π-donor strength the bond lengths Ni—O trans to the bridges are significantly shortened. In contrast to the analogous complex with an aliphatic bridge, “NiEIA”, both halves of the dimeric molecules are coplanar with a Ni—Ni distance of 3.29 Å.
    Notes: Die thermodynamisch stabile Form des solvensfreien, formal dreifach koordinierten Komplexes Ni(ONO) (ONO2- = Dianion des N-(2-Hydroxyphenyl)-2-ethoxycarbonyl-3-oxo-buten(1)-amin(1)) sowie die Monoaddukte Ni(ONO)X mit X = Ammoniak und Diphenylthioharnstoff (DPT) werden durch Röntgenstrukturanalyse charakterisiert. Das Zentralatom ist stets planarquadratisch koordiniert; nur das Addukt Ni(ONO)(DPT) zeigt eine durch die Ausbildung von Wasserstoffbrücken bedingte pyramidale Verzerrung. Die solvensfreie Form repräsentiert als Dimer [Ni(ONO)]2 eines der wenigen Beispiele dinuclearer Nickelkomplexe mit planarer NO3-Koordination. Als Brückenliganden wirken die Phenolatsauerstoffatome; aufgrund ihrer abgeschwächten π-Donorwirkung sind die transständigen Ni—O-Bindungen der Chelatsechsringe signifikant verkürzt. Im Gegensatz zum aliphatisch überbrückten Analogen „Ni(EIA)“ sind beide Molekülhälften coplanar mit einem Ni—Ni-Abstand von 3,29 Å angeordnet.
    Additional Material: 7 Ill.
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  • 5
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 6
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure Reactivity Correlations on Coordinatively Unsaturated Metal Chelate Complexes. XI. Effect of the Central Atom and the Ligands on the Mass Spectrometric Fragmentation of Chelate Complexes with Macrocyclic and Open Chain Schiff Base LigandsThe influence of the central atom on the mass spectrometric fragmentation of the compounds 1-5 is compared. Whereas the ligands (Mt = 2H) show a strong fragmentation with a farreaching cleavage, the metal complexes with exception of Cu-4 and Cu-5 show always the molecular ion signal as the base peak. The main fragmentions [M-C2H5O]⊕, [M-2(C2H5O)]2⊕, [M-C2H4]⊕., and [M-C2H4CO2]⊕. may be related to the ‘cyclidene’ structures 6-7, the carboxylic acid 8, and its decarboxylation product 9. In the case of the copper chelates 1-4 the fragment [M-C2H6O].⊕/2⊕ with one or two positive charges is dominating over the peak [M-C2H5O]⊕. This may be due to the abstraction of one H from an ethylene (type 1, 2, 4) or a methyl (type 3) group with concomitant reduction to Cu(I) (10) or oxidation to Cu(III) (11).
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  • 7
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substituted Alkinyles as Axial Ligands at Hemine Like Bound Iron(III) - Incorporation into a Spectrochemical Series.Substituted lithium alkynyles Li—C≡C—R (R = tBu, Ph, p-Cl—C6H4, Me3Si, iPr3Si, Ph3Si) react with the hemine like macrocyclic iron(III) complex 6,13-di(ethoxycarbonyl)-5, 14-dimethyl-1, 4, 8, 11-tetraazatetradeca-4,6,12,14-tetraenato[2-]iron(III)-iodide (formula 2;) in tetrahydrofuran to form anionic low-spin di-adducts [fe(C≡C—R)2]-. The incorporation of the alkynyles into a spectrochemical series of the axial ligands (studied by the sharp equatorial-ligand-to-metal CT absorption band) results in the wavelength-sequence (nm): OH- (≍ 510) « N3- (≍ 625) 〈 tBu—C≡C- (664) 〈 NH3 (666) 〈 Ph—C≡C- (692) 〈 Ph—NH2 (695) 〈 Me3Si—C≡C- (698) 〈 SCN- (713) 〈 Ph3Si—C ≡ C- (716) 〈 CN- (739) 〈 4-picoline (759) 〈 pyridine (765) 〈 nicotinamide (776) 〈 methylnicotinat (788) 〈 pyrazine (798) and points to a significant π-acceptor ability of the silyl substituents.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 349 (1967), S. 139-150 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Condensation products from 1, 2-diamines and hydroxymethylene malonic acid ester react with Cu(II) and Ni(II) to form stable, tricyclic 1: 1 chelates containing coordinated and free ester groups. Contrary to comparable N—0 coordinating 6ring chelates with acetyl or benzoyl oxygen as the ligand atom, the ester group coordination results in a decrease of the ligand field strength.The pure Ni chelates are diamagnetic giving, however, paramagnetic, stable solvates with pyridine. Only the free ester groups are released on treatment with methanolic KOH.
    Notes: Kondensationsprodukte aus 1,2-Diaminen und Oxymethylenmalonester bilden mit Cu(II) und Ni(II) stabile, tricyclische 1 : l-Chelate, die koordinierte und freie Estergruppen enthalten. Gegenüber vergleichbaren N—O-koordinierenden Sechsringchelaten mit koordiniertem Acetyl- oder Benzoylsauerstoff äußert sich die Einführung koordinierter Estergruppen in einer Erniedrigung der Ligandenfeldstärke. Die Nickelchelate sind in reiner Form diamagnetisch, mit Pyridin bilden sie beständige, paramagnetische Solvate. Bei der Verseifung der Komplexe in methanolischem Alkali werden nur dio freien Estergruppen angegriffen, die im Chelatring fixierten bleiben erhalten.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 364 (1969), S. 177-191 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Various β-ketoiminato- and β-diketonato-nickel(II) chelates react with liquid o-phenylendiamine to form neutral complexes which derive from 14-membered conjugated unsaturated macrocyclic ligands containing 16 π-electrons. The properties of these compounds are comparable with those of phthalocyanine and porphine complexes. Free meso-placed carbonyl groups in the starting material favour the reaction. The influence of several substituents on the properties of the compounds is described.
    Notes: Verschiedene β-Ketoiminato- und β-Diketonato-nickel(II)-chelate bilden in flüssigem ortho-Phenylendiamin makrozyklische Neutralkomplexe, die sich von konjugiert-ungesättigten, 14gliedrigen Ringsystemen mit 16 π-Elektronen ableiten. In ihren Eigenschaften stehen die Verbindungen den Porphin- und Phthalocyaninkomplexen nahe. Freie, mesoständige Carbonylgruppen im Ausgangsprodukt begünstigen die Reaktion. Der Einfluß verschiedener Substituenten auf die Eigenschaften der Verbindungen wird beschrieben.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 346 (1966), S. 76-91 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ethylenediamine- and ortho-phenylenediamine derivatives of oxymethylene-β-dicarbonyl compounds form with nickel(II) and copper(II) planar 1:1-chelate compounds with cis-[N2O2]-coordination, containing in meso-position a free carbonyl group —CO—R (R = CH3, OC2H5, C6H5). The chelates of the ester derivatives are saponifiable into free acids which have an unchanged coordination on the metal ion. The structure of the chelate compounds is discussed and the influence of the free carbonyl groups on the magnetical and spectral behaviour of the N—O-coordinated chelate compounds is explained.
    Notes: Äthylendiamin- und ortho-Phenylendiaminderivate von Oxymethylen-β-dicarbonylverbindungen bilden mit Nickel(II) und Kupfer(II) planare 1:1-Chelate mit cis-[N2O2]-Koordination, die am Chelatring in Mesostellung eine freie Carbonylgruppe —CO—R (R = CH3, C6H5, OC2H5) tragen. Die Esterderivate mit R = OC2H5 lassen sich zu Carbonsäuren mit unveränderter Koordination am Zentralatom verseifen. Die Struktur der Metallchelate wird diskutiert und der Einfluß freier Carbonylgruppen auf das magnetische und spektrophotometrische Verhalten N—O-koordinierender Sechsringchelate wird erläutert.
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