Die Koordinationszahl von Lanthaniden: Thermodynamik der LnIIIEDTA-Mischkomplexe mit den Anionen der 8-Hydroxychinolin-5-sulfonsäure,Iminodiessigsäure und Nitrilotriessigsäure

The values of ΔG, ΔH and ΔS for the formation of the mixed 1:1:1 lanthanide EDTA complexes with the anions of 8-hydroxyquinoline-5-sulfonic acid, iminodiacetic acid and nitrilotriacetic acid were determined by pH-titrations and a direct calorimetric method. These thermodynamic data are discussed and compared with those for the formation of the Ln(III)EDTA complexes. Contrary to current opinion it is concluded that all trivalent lanthanide aquoions have the same coordination number in dilute solution. However, in the series of the lanthanide EDTA complexes the coordination number changes between Sm and Tb. In this region, equilibria occur between two types of EDTA complexes with different numbers of coordinated water molecules: The corresponding equilibrium constants could be evaluated. The coordination number changes also in many other Ln complexes along the lanthanide series, and similar equilibria occur.     

Reaktionen von Organometallverbindungen, 3. Mitt.: Zur Kinetik der Reaktionen von Tetraorganoplumbanen mit Essigsäure

Zusammenfassung Die beiden Reaktionen (1) PbR₄+HacR₃Pbac+HR, (2) R₃Pbac+HacR₂Pbac ₂+HR laufen bei der Umsetzung von Pb(C₂H₅)₄ und Essigsäure in wasserfr. Toluol bei 60°, 80° und 100° als konkurrierende Folgereaktionen 2. Ordnung ab. Der Reaktionsablauf wurde durch Titration der Essigsäure mit KOCH₃-Lösung in wasserfr. Medium verfolgt, wobei die Geschwindigkeitskonstanten und die Aktivierungsenergien der Reaktionen ermittelt wurden.

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During the reaction of Pb(C₂H₅)₄ and acetic acid in anhydrous toluene at 60, 80 and 100° C the two reactions (1) and (2) proceed as competitive consecutive second order reactions. The reaction was studied by nonaqueous titration of acetic acid with KOCH₃-solution. Rate constants and activation energies have been determined.

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Mit 9 Abbildungen.

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Herrn Professor Dr.-Ing. habil.F. Asinger zum 60. Geburtstag gewidmet.

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Auszug aus der PromotionsarbeitH. Horn, Techn. Hochsch. Aachen 1966.

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2. Mitt.:F. Huber, H. Horn undH.-J. Haupt, Z. Naturforschg., im Druck.     

Synthese,Struktur und Reaktionen von Vanadiumsäureestern VO(OR)3: Umesterung und Reaktion mit Oxalsäure

Synthesis, Structure, and Reactions of Vanadium Acid Esters VO(OR)₃: Transesterification and Reaction with Oxalic Acid The reaction of tert.‐Butyl Vanadate VO(O‐tert.Bu)₃ ( 1 ) with H₂C₂O₄ in the primary alcohols ethanol and propanol results in the formation of (ROH)(RO)₂OV^V(C₂O₄)V^VO(OR)₂(HOR) (with R = C₂H₅ 2 and R = C₃H₇ 3 ). Compounds 2 and 3 are the first structurally characterized neutral, binuclear oxo‐oxalato‐complexes with pentavalent vanadium. The two vanadium atoms are connected by a bisbidentate oxalate group. The {VO₆} coordination at each vanadium site is completed by a terminal oxo group, an alcohol ligand and two alcoxide groups. The binuclear molecules are connected to chains by hydrogen bonding. In the case of 2 a reversible isomorphic phase transition in the temperature range of –90 °C to –130 °C is observed. From methanolic solution the polymeric Methyl Vanadate [VO(OMe)₃] ( 4 ) was obtained by transesterification. A report on the crystal structures of 1 , 2 and 3 as well as a redetermination of the structure of 4 is given. Crystal data: 1, orthorhombic, Cmc2₁, a = 16.61(2) Å, b = 9.274(6) Å, c = 10.784(7) Å, V = 1662(2) ų, Z = 4, d_c = 1.144 gcm^–1; 2 (–90 ° C) , monoclinic, I2/a, a = 33.502(4) Å, b = 7.193(1) Å, c = 15.903(2) Å und β = 143.060(3)°, V = 2303(1) ų, Z = 4, d_c = 1.425 gcm^–1; 2 (–130 ° C) , monoclinic, I2/a, a = 33.274(4) Å, b = 7.161(1) Å, c = 47.554(5) Å, β = 142.798(2)°, V = 6851(1) ų, Z = 12, d_c = 1.438 gcm^–1; 3 , triklinic, P1, a = 9.017(5) Å, b = 9.754(5) Å, c = 16.359(9) Å, α = 94.87(2)°, β = 93.34(2)°, γ = 90.42(2)°, V = 1431(1) ų, Z = 2, d_c = 1.340 gcm^–1; 4 , triklinic, P1, a = 8.443(2) Å, b = 8.545(2) Å, c = 9.665(2) Å, α = 103.202(5)°, β = 96.476(5)°, γ = 112.730(4)°, V = 610.2(2)ų, Z = 4, d_c = 1.742 gcm^–1.     

Reaktionen der Glucuronsäure, 4. Mitt.

Zusammenfassung Methyl--d-glucuron (Ia), Methyl--d-glucuron (IIa) und 1,2-Isopropyliden--d-glucuron (IIIa) wurden bei der Umsetzung mit Kohlensäurebenzylesterchlorid oder Kohlensäureäthylesterchlorid mit bemerkenswert verschiedener Geschwindigkeit acyliert. Bei den so erhaltenen Carbäthoxy- und Carbobenzoxy-derivaten trat im Gegensatz zu den entsprechenden Acetyl- und Benzoyl-derivaten unter den Bedingungen der Lactonringammonolyse keine Acylwanderung ein. Das unterschiedliche Verhalten der Glucuronsäurelactone wird als Folge unterschiedlicher Wasserstoffbrückenbindungen und Lactonringstabilitäten gedeutet.

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Reactions of glucuronic acid, IV: Syntheses with alkyl chloroformates

Acetyl and benzoyl derivatives of 1.2-isopropylidene-- and methyl- (and )-d-glucurone, resp., undergo acyl migration under the conditions of lactone ammonolysis. Using benzyl- and ethyl chloroformates remarkable differences in acylation rates with various glucuronic acid lactones were observed. The carbethoxy-and carbobenzoxy derivatives thus obtained show no tendency to rearrange under ammonolysis conditions. The results are interpreted as being due to hydrogen bonding and varying lactone ring stabilities.

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Mit 1 Abbildung

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Herrn Prof. Dr.O. Hromatka zum 65 Geburtstag in herzlicher Kollegialität gewidmet.

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Auszug aus der DissertationK. Dax, Technische Hochschule in Graz, 1970.

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3. Mitt.:H. Weidmann, E. Stieger undH. Schwarz Mh. Chem.101, 871 (1970).     

Synthese und Eigenschaften von 6-Desoxy-6-halogen-Derivaten der L-Ascorbinsäure

Synthesis and Properties of 6-Deoxy-6-halogeno-Derivatives of L -Ascorbic Acid 6-Deoxy-6-chloro-, -6-bromo-, -6-iodo- and -6-fluoro derivatives of L -ascorbic acid have been synthesized and characterized. The physiological properties of the chloro derivative have been investigated. It shows a high antiscurvy activity. The chloro- and bromo-derivatives have been reduced to the corresponding deoxy compound, which is an interesting chiral intermediate for the preparation of rare ω-deoxy sugars.     

Verbindungen der L-Ascorbinsäure mit Metallen. IV. Ligandeigenschaften des Monoanions der L-Ascorbinsäure,C6H7O6−

Compounds of L-Ascorbic Acid with Metals. IV. Ligand Properties of the Monoanion of L-Ascorbic Acid, C₆H₇O₆^? The ascorbates of some 3d elements of the general type M(Hasc)_n · xH₂O with M = Cr³⁺ (n = 3, x = 6), M = Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺ (n = 2, x = 4) are characterized by their hydrolytic and conductivity properties, magnetic moments, electronic and infrared spectra. The results of the coordination chemical investigations allow to determine the position of the Hasc^? ligand in the spectrochemical and nephelauxetic ligand series, and suggest the ligand to be bidentate.     

Schwefeldioxid als Ligand und Synthon. II. Synthese und Reaktionen der Trimethylsilyl-methansulfinsäure und ihrer Derivate

Sulfur Dioxide as Ligand and Synthon. II. Synthesis and Reaction of Trimethylsilyl Methane Sulfinic Acid and its Derivatives Synthesis and reaction of trimethylsilyl methane sulfinic acid and its derivatives, of the type Me₃SiCH₂S(O)? Y (Y = OH, OM, OR, NR₂) synthesized by insertion of SO₂ and R¹NSO, respectively, into Me₃SiCH₂MgCl are described. The compounds obtained are characterized by means of i.r., ¹H, ²⁹Si, and ¹³C n.m.r. spectroscopy.     

Bemerkungen zur Synthese von 3-Aminotoluol-5-sulfonsäure und 2-Aminotoluol-3-sulfonsäure

Some comments on the synthesis of 3-aminotoluene-5-sulfonic acid and 2-aminotoluene-3-sulfonic acid. Sulfonation of 3-nitrotoluene ( 5 ) yields predominantly the unsymetrical isomer 5-nitrotoluene-2-sulfonic acid ( 7 ), and lesser amounts of 5-nitrotoluene-3-sulfonic acid ( 6 ), previously reported as the major product. The desired 5-aminotoluene-3-sulfonic acid ( 3 ) was synthesized in preparative amounts from 6-aminotoluene-3-sulfonic acid (4) via the following sequence of reactions: diazotation and Sandmeyer replacement of 6-chlorotoluene-3-sulfonic acid ( 13 ), nitration of the sulfonyl chloride 14 under suitable conditions to give isomer free 6-chloro-5-nitrotoluene-3-sulfonyl chloride ( 15 ), hydrolysis to the sulfonic acid 16 and finally, simultaneous hydrogenolysis and reduction to 3 . The isomeric 7 was unequivocally prepared from 2-amino-5-nitrotoluene ( 9 ) via two routes: (1) diazotation, Sandmeyer thiocyanatation to 5-nitro-2-thiocyanatotoluene ( 10 ), Na₂S reduction to the di(2-methyl-4-nitro-phenyl)-disulfide ( 11 ), treatment with nitric acid and chlorine to give 5-nitrotoluene-2-sulfonyl chloride ( 12 ) and finally alkaline hydrolysis to 7 ; (2) Meerwein's SO₂ treatment of the diazonium salt derived from 9 leads directly to 12 and thence to 7 . 2-Aminotoluene-3-sulfonic acid ( 1 ) was prepared from the key intermediate 3-amino-2-nitrotoluene ( 18 ) via the same two routes used to prepare 7 from 9 . Both reaction sequences provided 2-nitrotoluene-3-sulfonly chloride, the hydrolysis product of which was reduced to 1 . Intermediate 18 was prepared in the following four steps from m-toluic acid ( 19 ): nitration to the 2-nitroderivative ( 20 ), whose acid chloride ( 21 ) was converted to 2-nitro-m-toluamide ( 22 ), and Hoffmann rearrangement to 18 .     

Reaktionen von o-Chinolacetaten mit Diazoalkanen, 2. Mitt.: Synthese von substituierten 5-Hydroxyindazolen

Zusammenfassung o-Benzochinolacetate, die in 3,4-Stellung unsubstituiert und in Position 5 substituiert sind, addieren Diazomethan an den Stellungen 3,4 unter Bildung von Verbindungen des Typus VIII. Diese sind thermisch leicht und in guter Ausbeute in substituierte 5-Hydroxyindazole umwandelbar. Weiterhin werden einige Umsetzungen von VIII beschrieben.Mit 1 Abbildung     

Reaktionen von 3-Dimethylamino-2,2-dimethyl-2H-azirin mit. NH-aciden Heterocyclen; Synthese von 4H-imidazolen

Reactions of 3-Dimethylamino-2,2-dimethyl-2H-azirine with NH-Acidic Heterocycles; Synthesis of 4H-Imidazoles In this paper, reactions of 3-dimethylamino-2,2-dimethyl-2H-azirine ( 1 ) with heterocyclic compounds containing the structure unit CO? NH? CO? NH are described. 5,5-Diethylbarbituric acid ( 5 ) reacts with 1 in refluxing 2-propanol to give the 4H-imidazole derivative 6 (Scheme 2) in 80% yield. The structure of 6 has been established by X-ray crystallography. Under similar conditions 1 and isopropyl uracil-6-carboxylate ( 7 ) yield the 4H-imidazole 8 (Scheme 3), the structure of which is deduced from spectral data and the degradation reactions shown in Scheme 3. Hydrolysis of 8 with 3N HCl at room temperature leads to the α-ketoester derivative 9 , which in refluxing methanol gives dimethyl oxalate and 5-dimethyl-amino-2,4,4-trimethyl-4H-imidazole ( 10 ). On hydrolysis the latter is converted to the known 2,4,4-trimethyl-2-imidazolin-5-one ( 11 ) [6]. Quinazolin-2,4 (1H, 3H)-dione ( 12 ) and imidazolidinetrione (parabanic acid, 14 ) undergo with 1 a similar reaction to give the 4H-imidazoles 13 and 15 , respectively (Schemes 4 and 5). In Scheme 6 two possible mechanisms for the formation of 4H-imidazoles from 1 and heterocycles of type 16 are formulated. The zwitterionic intermediate f corresponds to b in Scheme 1. Instead of dehydration as in the case of the reaction of 1 with phthalohydrazide [3], or ring expansion as with saccharin and cyclic imides [1] [2], f , undergoes ring opening (way A or B). Decarboxylation then leads to the 4H-imidazoles 17 .