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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 703-706 
    ISSN: 0009-2940
    Keywords: 4,4′-Spirobi(1,3-diaza-2-bora-4-metallacyclobutanes)/1,3-Diaza-2-bora-4-metallacyclobutanes/Metallaheterocycles with Ge, Sn, Ti, Zr ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N,N′-Dilithiobis(alkylamino)phenylboranes as Starting Materials for Four-Membered MetallacyclesReactions of N,N′-Dilithiobis(alkylamino)phenylboranes with tetrachlorides MCl4 (M = Ge, Sn, Ti, Zr) produce the 4,4′-spirobi(1,3-dialkyl-2-phenyl-1,3-diaza-2-bora-4-metalla-cyclobutane) derivatives 1a, 1b, 2b, 3a, and 3b. With diorganylmetal dihalides R2MX2(M = Sn, Zr; X = Cl, Br), the 1,3-diaza-2-bora-4-metallacyclobutanes 2a and 4 are obtained. For 3a an X-ray structure analysis has been performed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2223-2225 
    ISSN: 0009-2940
    Keywords: Lithium, two-coordinate ; Lithium-nitrogen heterocycle ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [LiN(SiMe3)Ar]2 (1, Ar = 2,6-iPr2C6H3) is prepared by the reaction of HN(SiMe3)Ar with nBuLi in n-hexane. This compound with an unusual structure contains a four-membered [LiN]2 heterocycle with two solvent-free two-coordinate Li centers. Its molecular structure represents the first solid-state X-ray analysis of an uncomplexed [LiN]2 dimer.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 0009-2940
    Keywords: Bulky substituents ; Aluminum compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Structure of CpAlCl2 Compounds with Sterically Demanding Substituents (Cp = Me5C5, EtMe4C5)[1]The compounds Cp*AlCl2 (3) (Cp* = Me5C5) and Cp′AlCl2 (4) (Cp′ = EtMe4C5) have been prepared by the reaction of Cp*SiMe3 (1) and Cp′SiMe3 (2) with AlCl3. The single-crystal X-ray structures of 3 and 4 are reported.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 0009-2940
    Keywords: Bis(1,2,3-triborolane) ; Isopropylbenzene, tetraborylated ; 1,2-Bis(diisopropylamino)-1,2-diphenylborane-(4) ; 1,1,2,2-Tetrakis(boryl)ethane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polycyclic Compounds from 2,5-Norbornadiene, Isopropylbenzene, and Dehalogenation Products of Dihalogeno(diorganylamino)boranes. Reaction of Bis(diisopropylamino)phenylborane with Na/K Alloy and Difluoro(diisopropylamino)boraneIn the reaction of 2,5-norbornadiene with Na/K alloy and dichloro(diisopropylamino)borane the species 1 was isolated, which contains six boron atoms in two triborolane rings. From isopropylbenzene and the dehalogenation products of (diisobutylamino)difluoroborane the ethenodiborolodiborol system 2 was isolated. When bis(diisopropylamino)phenylborane is treated with F2BN(i-C3H7)2 and Na/K alloy the diborane(4) derivative 5 and 1,1,2,2-tetrakisborylethane (6) are formed together with bis(diisopropylamino)fluoroborane (7). NMR (1, 11B, 13C, 19F) and MS data are given; for 1, 2, 5, and 6 the X-ray structure analyses were performed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of a glycopeptide antibiotic A-40926 aglycone was investigated by X-ray analysis at -120°. A-40926 crystallises in the orthorhombic space group P212121 with two monomers in the asymmetric unit, a = 21.774(4), b = 28.603(7), c = 29.757(4) Å. ‘Conventional’ direct methods approach failed to solve the structure, but a novel iterative real/reciprocal space procedure was successful. Refinement against 11248 F2 data led to R1 = 13.3% for 6770 F 〉 4σ (F). The two monomers of A-40926 have similar conformations and are bound by antiparallel H-bonds to form a ‘chain’ structure of connecting dimers. The antibiotic molecule possesses a ‘binding pocket’ for the C-terminal carboxy group of the cell-wall protein, which is consisten with suggestions based on NMR data and the recently reported crystal structure of ureido-balhimycin. In A-40926 the monomers are polymerically linked by H-bonds, quite unlike the tight dimer formation observed in ureido-balhimycin.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 79 (1996), S. 1635-1642 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of isocyclosporin A (1), a rearrangement product of the immunosuppressant drug cyclosporin A, has been determined at 193 (2) K. Crystals are orthorhombic with cell dimensions a = 26.684 (7), b = 26.936 (3) Å, c = 28.549 (7) Å, space group C2221. The structure was solved by direct methods and refined by full-matrix least-squares methods to a conventional R value of 0.110. In contrast to the structure of cyclosprin A in solution and in the crystal, isocyclosporin A (1) has no regular secondary structural elements. The backbone adopts an open, irregular conformation with cis amide bonds between residue 2 and 3, and 3 and 4, respectively. All the other amide bonds and the ester linkage are trans. Contrary to crystal structures of cyclosporin derivatives, this crystal structure is stabilized by two transannular and four intermolecular H-bonds.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 724-731 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N,N′-Dihalogenoethanediirnidoyl DifluoridesThe title compounds XN=CF—CF=NX (13, 14, X = Cl, Br) are prepared in a simple way from the three components (CN)2, X2, and HgF2. The N-halogenated amino- or iminoperfluoroethanes Cl2N—CF2—CF2—NCl2 (11), ClN=CF—CF2—NCl2 (12), BrN=CF—CF2—NBr2 (15) and Br2N—CF2—CF2—NBr2 (16) were identified as further products. The structure of 14 was determined from single-crystal X-ray data.
    Notes: Die Titelverbindungen XN=CF—CF=NX (13, 14, X = Cl, Br) lassen sich in einfacher Weise aus den drei Komponenten Dicyan, X2 und HgF2 gewinnen. Als weitere Produkte konnten die N-halogenierten Amino- bzw. Iminoperfluorethane Cl2N—CF2—CF2—NCl2 (11), ClN=CF-CF2—NCl2 (12), BrN=CF—CF2—NBr2 (15) und Br2N—CF2—CF2—NBr2 (16) nachgewiesen werden. Aus Einkristall-Röntgenbeugungsdaten wurde die Struktur von 14 bestimmt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Metal and Metalloid Compounds with Polyfunctional Molecules, XXXVIII. The Reaction of Ethanediamides with BromodimethylboraneReactions of symmetrically substituted N,N′-dialkyl-(diaryl)ethanediamides A with bromodimethylborane are investigated. Reactions in the molar ratio of 1 : 2 yield the 2,6-dioxonia-4,8-diaza-3,7-diboratabicyclo[3.3.0]octanes 1a - j, the N,N′-bis(dimethylboryl)-N,N′-diorganylethanediamides 4a, b, and the equilibrium mixtures 3a - d. By-products are 2-oxonia-4-oxa-6-azonia-8-aza-3,7-diboratabicyclo[3.3.0]octanes 2a - j. By the reaction of N,N′-diorganylethanediamides with bromodimethylborane in the molar ratio 1 : 1 the 1-oxonia-3-aza-2-boratacyclopentan-4-one derivatives 5a - e, N-(dimethylboryl)-N,N′-diorganylethanediamides 6a - c, the equilibrium mixtures 7a - d, and the 5-(alkylamino)-4-(alkylimonio)-2,2-dimethyl-1-oxonia-3-oxa-2-boratacyclopentane bromides 8a - h are obtained. X-ray analyses have been carried out for 1a, 5a, e and 8b.
    Notes: Es werden Reaktionen symmetrisch substituierter N,N′-Dialkyl-(Diaryl)ethandiamide A mit Bromdimethylboran untersucht. Die Reaktion im Molverhältnis 1 : 2 führt zu 2,6-Dioxonia-4,8-diaza-3,7-diboratabicyclo[3.3.0]octanen 1a - j, N,N′-Bis(dimethylboryl)-N,N′-diorganylethandiamiden 4a, b und den Gleichgewichtsmischungen 3a - d. Als Nebenprodukte treten 2-Oxonia-4-oxa-6-azonia-8-aza-3,7-diboratabicyclo[3.3.0]octane 2a - j auf. Bei der Umsetzung von N,N′-Diorganylethandiamiden mit Bromdimethylboran im Molverhältnis 1 : 1 erhält man die 1-Oxonia-3-aza-2-boratacyclopentan-4-on-Derivate 5a - e, N-(Dimethylboryl)-N,N′-diorganylethandiamide 6a - c, Gleichgewichtsmischungen 7a - d und 5-(Alkylamino)-4-(alkylimonio)-2,2-dimethyl-1-oxonia-3-oxa-2-boratacyclopenta n-bromide 8a - h. Für 1a, 5a, e und 8 b wurden Röntgenstrukturanalysen durchgeführt.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 416-423 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 4-Chloro-1,2,3,5-dithiadiazolium SaltsThe synthesis of 4-chloro-1,2,3,5-dithiadiazolium chloride (9) from SCI2 and either N-cyanosulfur difluoride imide (8) or bis(trimethylsilyl)carbodiimide (12) is described. The analogous dibromide 13 is formed from S2Br2 and 8. The ionic chlorine in 9 may easily be exchanged with the help of silver salts, acids, and Lewis acids yielding ClCN2S2+A- (9a-d, A- = AsF6-, SbCl6-. ½SnCl62-, SO3-). The crystal structure of the hexafluoroarsenate 9a has been determined.
    Notes: Die Synthese von 4-Chlor-1,2,3,5-dithiadiazolium-chlorid (9) aus N-Cyanoschwefeldifluoridimid (8) bzw. aus Bis(trimethylsilyl)carbodiimid (12) und SCI2 wird beschrieben. Das zu 9 analoge Dibromid 13 entsteht aus 8 und S2Br2. Mit Hilfe von Silbersalzen, Säuren und Lewis-Säuren läßt sich das ionisch gebundene Chlor in 9 leicht austauschen unter Bildung von CICN2S2+A- (9a-d, A- = AsF6-, SbCl6-, ½SnCl62-, SO3F-). An dem Hexafluoroarsenat 9a wurde eine Kristallstrukturbestimmung durchgeführt.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 146-151 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclisation of (Fluorsilyl)phosphanes to 1,3-Diphospha-2,4-disilacyclobutanes - Crystal Structure DeterminationsLithiated tert-butylphosphane reacts with di-tert-butyldifluorosilane and with difluorobis[methyl(trimethylsilyl)amino]silane to give the (fluorosilyl)phosphanes 1 and 2 as well as the (di-tert-butylsilanediyl)bisphosphane 3. The cyclic compounds 4 and 5 are obtained in the reaction of 1 and 2 with tert-C4H9Li. Dilithiated 3 reacts with dichlorophenylphosphane to form the 1,2,3-triphospha-4-silacyclobutane 6. According to crystal structure analyses, 4 and 5 contain planar Si2P2 rings with Si—P bonds between 224.1(1) and 228.0(1) pm.
    Notes: Lithiiertes tert-Butylphosphan reagiert mit Di-tert-butyldifluorsilan und Difluorbis[methyl(trimethylsilyl)amino]silan zu den (Fluorsilyl)phosphanen 1 und 2 sowie zum (Di-tert-butylsilandiyl)-bisphosphan 3. Die cyclischen Verbindungen 4 und 5 werden durch die Umsetzung von 1 und 2 mit tert-C4H9Li erhalten. Dilithiiertes 3 reagiert mit Dichlorphenylphosphan zum 1,2,3-Triphospha-4-silacyclobutan 6. Nach Kristallstrukturanalysen besitzen 4 und 5 jeweils planare Si2P2-Ringe mit Si—P-Bindungen zwischen 224.1(1) und 228.0(1) pm.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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