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  • 1
    Electronic Resource
    Electronic Resource
    On-column capillary flow cell utilizing optical waveguides for chromatographic applications (1989)
    s.l. : American Chemical Society
    Analytical chemistry 61 (1989), S. 876-883 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac00183a019
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  • 2
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Bors, 140. Bor-, Aluminium- und Galliumhalogenid-Addukte einer Tetraaminodibor-Verbindung (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2495-2503 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 1401). Boron, Aluminium, and Gallium Halide Adducts of a Tetraaminodiboron CompoundThe tetraamino diboron compound 1 adds trihalides EX3 (E = B, Al, Ga, X = Cl, Br, I) to yield 1:1- and 1:2-coordination compounds. The BBr3 adduct 1b is thermally stable and shows nonfluxional behaviour in solution in contrast to the AlCl3 and GaCl3 adducts. The 1:2 adducts are nonfluxional and, according to NMR spectra, only the meso-form is present. The structure of the 1:1-adducts was ascertained by an X-ray structure determination of 1g. The single crystal contained R configurated molecules. A change from planar to the envelope conformation of the diazaborolidine ring occurs on adduct formation.
    Notes: Die Tetraaminodibor-Verbindung 1 lagert die Trihalogenide EX3 (E = B, Al, Ga; X = Cl, Br, I) zu 1:1- bzw. 1:2-Koordinationsverbindungen an. Von diesen zeigt nur das thermisch stabilere BBr3-Addukt 1b in Lösung im Gegensatz zu den AlCl3- und GaCl3-Addukten kein fluktuierendes Verhalten. Die 1:2-Addukte sind starr, und nach NMR-Spektren bildet sich nur die meso-Form. Die Struktur der 1:1-Addukte wurde durch Röntgenstrukturanalyse von 1g gesichert; die Einkristalle enthielten ein R-konfiguriertes Molekül. Durch die Addition nimmt der sonst planare Diazaborolidin-Ring Briefumschlag-Konformation an.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170720
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  • 3
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Bors, 139. Additionsverbindungen von Alkylhalogenboranen mit 1,3,2-Diazaborolidinen: Struktur, Stabilität und Austauschreaktionen (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2479-2494 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 139. Addition Compounds of Alkylhalogenoboranes with 1,3,2-Diazaborolidines: Structure, Stability, and Exchange ReactionsReactions of alkylhalogenoboranes RnBX3 - n (n = 0 - 2) with the 1,3-dimethyl-1,3,2-diazaborolidines 1 - 4 yield stable 1:1 addition compounds 1a - e, 2a, 3a - d, 4a irrespective of the boron substituents. Coordination of the borane moiety occurs at a ring N atom. An X-ray structure determination of the BCl3-adduct 3a shows two enantiomers in the asymmetric unit, envelope ring conformation, and strong π-bonding between the non-coordinated B an N atoms. - Equilibria of the 1:1 adducts with their ring cleavage products and their behaviour towards a second mol of BX3 was studied. In this case, replacement of the ring-BR group occurs. In contrast, haloboranes react with the 2-(dimethylamino)diazaborolidine 5 with R2N-substituent exchange while diborane yields in the first instance the (dimethylamino)borane adduct 5a.
    Notes: Umsetzungen von Alkylhalogenboranen RnBX3 - n (n = 0 - 2) mit den 1,3-Dimethyl-1,3,2-diazaborolidinen 1 - 4 führen unabhängig vom Bor-Substituenten zu stabilen 1:1-Additionsverbindungen 1a - e, 2a, 3a - d, 4a, wobei die Koordination über ein N-Atom des Fünfrings erfolgt. Die Röntgenstrukturanalyse des BCl3-Addukts 3a zeigt zwei enantiomere Formen in der asymmetrischen Einheit, “envelope”-Ringkonformation und eine starke π-Rückbindung des Ringbors zum nicht koordinierten Stickstoff. - Gleichgewichte der 1:1-Additionsverbindungen mit ihrem Ringöffnugsprodukt sowie ihr Verhalten gegenüber einem zweiten mol Lewis-Säure wurden untersucht. Hierbei wird die Ring-BR-Gruppe verdrängt. Im Gegensatz dazu tauscht das 2-(Dimethylamino)diazaborolidin 5 mit Halogenboranen den R2N-Substituenten aus, während die Umsetzung mit Diboran zunächst ein wenig stabiles (Dimethylamino)boran-Addukt 5a liefert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170719
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  • 4
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Bors, 118. Struktur und Dynamik von Hexamethylborazin-Aluminiumbromid (1981)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 2723-2730 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron 118. Structure and Dynamics of Hexamethylborazine-Aluminium TribromideAluminium tribromide in its 1:1 adduct with hexamethylborazine coordinates with one nitrogen atom. This results in a loss of the planarity of the borazine ring system, and the BN bond lengths vary now from 139 to 154 pm as shown from an X-ray crystal structure determination of the monoclinic adduct (Rw = 0.076). The ring conformation is additionally influenced by weak intramolecular and intermolecular Br-B interactions. The adduct shows fluctional behaviour in solution at temperatures higher than 276 K.
    Notes: Aluminiumbromid koordiniert in seinem 1: 1-Addukt mit Hexamethylborazin über ein N-Atom Der Borazin-Ring verliert dadurch seine Planarität, seine BN-Abstände variieren zwischen 139 und 154 pm, wie aus der Röntgenstrukturanalyse des monoklin kristallisierenden Addukts her-vorgeht (Rw = 0.076). Die Ringkonformation wird durch schwache intramolekulare und intermolekulare Br-B-Wechselwirkungen geprägt. In Lösung zeigt das Addukt fluktuierendes Verhalten oberhalb von 276k.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19811140806
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  • 5
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Bors, 134. Addukte von (Dimethylamino)boranen mit Aluminum- und Galliumhalogeniden (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 863-874 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 134. Adducts of (Dimethylamino)boranes with Aluminium and Gallium Halides2)The (dimethylamino)boranes (CH3)2BN(CH3)2 (1) and RB[N(CH3)2]2 (2, 3) form 1 : 1 adducts 1a - c and 2a, b, 3a, b with AlCl3, AlBr3, and GaCl3, respectively, in contrast to B[N(CH3)2]3 (4) which reacts with GaCl3 to produce a 1:2 adduct 4a. NMR and IR data are in accord with the presence of a simple N - Al or N - Ga coordinative bound for the first two classes of compounds. However, 4a is to be regarded as a tris(dimethylamino)borane-dichlorogallium(1+) tetrachlorogallate containing a bidentate aminoborane component.
    Notes: Die (Dimethylamino)borane (CH3)2BN(CH3)2 (1) und RB[N(CH3)2]2 (2, 3) bilden mit AlCl3, AlBr3 und GaCl3 1 : 1-Addukte 1a - c und 2a, b, 3a, b, während B[N(CH3)2]3 (4) mit GaCl3 zu einem 1:2-Addukt 4a reagiert. NMR- und IR-Daten weisen den beiden erstgenannten Verbindungstypen Strukturen mit einer einfachen N - Al- bzw. N - Ga-Koordination zu. Im Gegensatz dazu ist 4a als Tris(dimethylamino)boran-dichlorgallium(1+)-tetrachlorogallat aufzufassen, in der die Aminoboran-Komponente als zweizähniger Ligand wirkt.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170302
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  • 6
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Bors, 142. Über einige Substitutionsreaktionen an 1,3-Dimethyl-1,3,2-diazaborolidinen und die anomale Dimerisierung des 2-Fluor-Derivats (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2542-2546 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Boron, 142. Some Substitution Reactions of 1,3-Dimethyl-1,3,2-diazaborolidines and the Anomalous Dimerisation of its 2-Fluoro DerivativeThe transamination of B[N(CH3)2]3 with α,ω-dimethylalkylenediamines proceeds via the bridged species 2 and 3. These react with boron halides to yield 2-halo-diazaborolidines. The 2-fluoro derivative 6 has been obtained from fluorination of the 2-methylthio compound with SbF3. 6 dimerizes in an anomalous fashion yielding a fluxional tricyclic species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170727
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  • 7
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Bors, 135. Additionsverbindungen von 1,3,2-Diazaborolidinen mit Aluminium- und Galliumhalogeniden (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1222-1234 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 1351). Addition Compounds of 1,3,2-Diazaborolidines with Aluminium and Gallium Halides1,3-Dimethyl-1,3,2-diazaborolidines 3 - 6 add aluminium and gallium halides, respectively, in a 1 : 1 molar ratio. The ligand is monodentate in these coordination compounds (3a - e, 4a, 5a, b, 6a). Addition occurs at one of the ring nitrogen atoms irrespective of the B-substituent. A consequence of this coordination is a long BN bond to the chiral tetracoordinated nitrogen atom as well as a considerable shortening of the BN bond involving the tricoordinate ring nitrogen. In addition, the almost planar five-membered ring adopts the envelope conformation as shown by an X-ray structure analysis of 5a. In contrast, the 2-(dimethylamino)diazaborolidine 7 yields unstable 1 : 1 besides stable 1 : 2 adducts 8. In these the Lewis acid is also coordinated to the ring nitrogen atoms only.
    Notes: Die 1,3-Dimethyl-1,3,2-diazaborolidine 3 - 6 addieren Aluminium- oder Galliumhalogenide im Molverhältnis 1 : 1 zu Koordinationsverbindungen 3a - e, 4a, 5a, b, 6a, in denen der Ligand einzähnig ist. Die Anlagerung erfolgt unabhängig vom B-Substituenten an einem Ringstickstoff-Atom. Folge dieser Koordination ist die Ausbildung einer langen BN-Bindung zum chiralen tetra-koordinierten Ring-Stickstoff, eine erhebliche Verkürzung der BN-Bindung zum dreifach koordinierten endocyclischen Stickstoffatom und der Übergang des nahezu planaren Fünfrings in die „envelope“-Konformation, wie die Röntgenstrukturanalyse von 5a belegt. Im Gegensatz dazu liefert das 2-(Dimethylamino)diazaborolidin 7 mit AlX3 und GaX3 instabile 1 : 1- und stabile 1 : 2-Addukte 8. In diesen ist die Lewis-Säure nur an den Ringstickstoff-Atomen koordiniert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170334
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  • 8
    Electronic Resource
    Electronic Resource
    Beiträge zur Chemie des Bors, 127. Hexamethylborazin-Galliumtrichlorid: Struktur in Lösung und in festem Zustand (1982)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2668-2673 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Boron, 127. Hexamethylborazine-Gallium Trichloride: Structure in Solution and in the Solid StateHexamethylborazine forms a 1:1 adduct 1 with gallium trichloride. It is isostructural with hexamethylborazine-aluminium tribromide. The BN heterocycle is no longer planer, and the molecule adapts almost Cs symmetry and contains a tetracoordinated nitrogen atom. 1 shows fluctional behavior in toluene solution at room temperature. The coordinated GaCl3 will no longer change its coordination site at T 〈 220 K (two signals each for the CH3N-and CH3B-protons). However, at T 〈 195 K an additional splitting of the signals is observed - three signals for each type of CH3 groups: this would be consistent with a pentacoordinated gallium atom and a bidentate borazine ligand.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19821150730
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