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  • 1
    Electronic Resource
    Electronic Resource
    X-ray Crystallographic Structure of a 7-Aza-nido-undecaborane Derivative: (NB2tBu3H)NB10H12 (1995)
    s.l. : American Chemical Society
    Inorganic chemistry 34 (1995), S. 5925-5926 
    Details
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ic00127a034
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  • 2
    Electronic Resource
    Electronic Resource
    Expansion of Three-Membered Rings by the Insertion of Methyl(methylidene)borane MeB:C(SiMe3)2 (1995)
    s.l. : American Chemical Society
    Organometallics 14 (1995), S. 1507-1509 
    Details
    ISSN: 1520-6041
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/om00003a061
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  • 3
    Electronic Resource
    Electronic Resource
    Five- and Six-Coordinate Nitrogen in Azaborane Clusters (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 143-153 
    Details
    ISSN: 1434-1948
    Keywords: Azaboranes ; Six-coordinate nitrogen ; Deltahedral clusters ; Cluster opening ; Cluster closure ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the majority of known azaboranes NaBbHc and their derivatives, the coordination number of the nitrogen atoms within the cluster does not exceed the classical values of 3 or 4. In the azaboranes closo-NB9H10, nido-NB10H13, and closo-NB11H12 and in their derivatives, however, the nitrogen atoms are 5- or 6-coordinate and thus represent a novel bonding situation. The synthesis, structure, and reactivity of these azaboranes are reviewed in this article.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Azametalla-closo-dodecaboranes (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 719-724 
    Details
    ISSN: 0044-2313
    Keywords: Undecahydroaza-nido-undecaborate(2-) ; azametalla-closo-dodecaboranes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azametalla-closo-dodecaboraneAus nido-NB10H13 erhält man mit der doppelten Menge an K[BHEt3] das Azaborat K2[nido-NB10H11]. Das Anion [NB10H112-] ist isoelektronisch mit [C2B9H11]2-. Es reagiert mit [{η6-(C6R6)RuCl2}2] (R = H, Me), [{η5-(C5Me5)RhCl2}2] oder [Ni(PPh3)2Cl2] zu den Azametalla-closo-dodecaboranen MNB10H11 mit M = (C6Me6)Ru (2), (C6H6)Ru (3), (C5Me5)Rh (4) bzw. (Ph3P)2Ni (5). Aus K2[NB10H11] und CoCl2 läßt sich das Azametallaboran K[Co(NB10H11)2] (6) gewinnen, in welchem das Co-Atom sandwichartig von zwei [NB10H11]2--Ionen koordiniert wird. Vom Produkt 2 · CH2Cl2 liegt eine Röntgenstrukturanalyse vor. Die Produkte 2-6 lassen sich vom ikosaedrisch gebauten Anion [B12H12]2- dadurch ableiten, daß eine BH2--Einheit durch das isoelektronische Nitren NH und eine BH-Einheit durch das isolobale Metallkomplex-Fragment M ersetzt werden. Das N-Atom ist in den Clustergerüsten 2-6 jeweils sechsfach koordiniert.
    Notes: The azaborate K2[nido-NB10H11] is gained from nido-NB10H13 and K[BHEt3] in a 1:2 ratio. The anion [NB10H11]2-, which is isoelectronic with [C2B9H11]2-, reacts with [{η6-(C6R6) · RuCl2}2] (R = H, Me), [{η5-(C5Me5)RhCl2}2], or [Ni(PPh3)2Cl2] to give the azametalla-closo-dodecaboranes MNB10H11 with M = (C6Me6)Ru (2), (C6H6)Ru (3), (C5Me5)Rh (4), and (Ph3P)2Ni (5), respectively. The azametallaborane K[Co(NB10H11)2] (6), which contains a sandwich-type coordinated Co atom, is formed from K2[NB10H11] and CoCl2. The structure of 2 · CH2Cl2 was determined by X-ray diffraction. The products 2-6 can be derived from the icosahedral anion [B12H12]2- on replacing a BH2- moiety by the isoelectronic nitrene NH and a BH moiety by the isolobal metal-complex fragment M. The N atom is six-coordinated in the cluster skeletons 2-6.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210504
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  • 5
    Electronic Resource
    Electronic Resource
    Electrophilic Substitution at the NB9 and NB11 closo-SkeletonsDedicated to Professor Kurt Dehnicke on the occasion of his 65th birthday (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1227-1231 
    Details
    ISSN: 0009-2940
    Keywords: Aza-closo-decaboranes, halogenation of, methylation of ; Aza-closo-dodecaboranes, halogenation of, methylation of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The aza-closo-boranes ArNB9H9 (1, Ar = p-ClC6H4) and MeNB11H11 (2) were brominated, iodinated, or methylated under Friedel-Crafts conditions to give ArNB9H4Br5 (3), ArNB9H7I2 (4), ArNB9H4Me5 (7), MeNB11H10Br (5), MeNB11H10I (6), and MeNB11H5Me6 (9), respectively. The upper boron belt adjacent to nitrogen is not involved in the substitution reactions with 1 and 2. The antipodal position and the lower belt are attacked by electrophiles in the case of 1; the antipodal position is the preferred one in the case of 2. By prolongated action of triflic acid on the methylated species 7 and 9, one methyl group is replaced by the triflate group to give ArNB9H4Me4(OTrf) (8) and MeNB11H5Me5-(OTrf) (10) with this group in the positions 6 and 12, respectively. The NMR data indicate the cluster symmetries Cs (4, 8), C4v (3, 7), and C5v (5, 6, 9, 10). Crystal structure investigations of 5 (space group Cc) and 10 (space group C2/c) showed that the molecular dimensions of the NB11 skeleton are comparable to those of closo, -(PhCH2)NB11H11.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291014
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  • 6
    Electronic Resource
    Electronic Resource
    Thiaaza-arachno-pentaboran SNB3H2tBu3R (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1105-1108 
    Details
    ISSN: 0009-2940
    Keywords: Azadiboriridine, tri-tert-butyl- ; Mercaptoborane ; Thiaaza-arachno-pentaborane, 1,4,5-tri-tert-butyl-2-organo- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thiaaza-arachno-pentaborane SNB3H2tBu3RThe azadiboriridine [-B(tBu)-N(tBu)-B(tBu)-] (1) gives 1:1 adducts with the mercaptoboranes BH2(SR), which can be generated from their cyclotrimers by the action of THF. The adduct 4a (R = Ph), a nido cluster with an NB3 skeleton, forms an equilibrium with an adduct 5a, an arachno cluster with an SNB3 skeleton, whose S-bound ligand Ph is found in an endo position by an X-ray structural analysis. The equilibrium 4a · 5a involves a Lewis acid-base reaction, which is electronically coupled to a reduction of a three-center to give a two-center π bond. The reaction of 1 with BH2(SPr) gives the corresponding arachno cluster 5b only.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951281108
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  • 7
    Electronic Resource
    Electronic Resource
    1,1-Hydroborierung von Alkinen mit 6-Aza-nido-decaboranen (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 947-951 
    Details
    ISSN: 0009-2940
    Keywords: 6-Aza-nido-decaborane ; 9-(1-Alkenyl)-6-phenyl-6-aza-nido-decaborane ; 1,1-Hydroboration of alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,1-Hydroboration of Alkynes with 6-Aza-nido-decaboranes[1]Alkynes AC≡CR′ (R′ = Me, Bu, tBu, SiMe3), that contain a mobile group A, like H or SiMe3, undergo hydroboration by 6-aza-nido-decaboranes RNB9H11 (1a-c, R = H, Ph, PhCH2) and 1,2-migration of the group A, to give the corresponding 9-(1-alkenyl)-6-aza-nido-decaboranes RNB9H10(CH=CR′A) (2a-h). Ethenes AHC=CH2 (A = SiMe3, SnBu3) are hydroborated by 1a, b as well to form products of the type RNB9H10(CH2CH2A) (3a-c). The alkyne Me3SiC=CH undergoes a hydroboration with 1b twice; the formation of (PhNB9H10)2CHCH2SiMe3 (4) proceeds by a 1,1- and a 1,2-hydroboration step, apparently. The crystal structure analysis of (PhCH2)NB9H10[CH=CMe(SiMe3)] (2e; space group Pl) reveals a (Z configuration of the ethene moiety.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951280916
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  • 8
    Electronic Resource
    Electronic Resource
    Tri-tert-butylazadiboriridin: Ringerweiterung mit Isonitrilen, α-Bromlithioalkanen und Aziden (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1029-1035 
    Details
    ISSN: 0009-2940
    Keywords: Azadiboracyclobutanes ; Azadiboracyclopentanes ; Azadiboriridine, ring-opening of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tri-tert-butylazadiboriridine: Ring Prolongation by the Action of Isonitriles, α-Bromolithioalkanes, and AzidesIsonitriles ArNC are 1,1-boroborated by the B-B bond of the azadiboriridine (-BR-BR-NR-) (1; R = tBu) to form the four-membered ring [-BR-C(NAr)-BR-NR-] (2b; Ar = 2,6-C6H3Me2). Corresponding rings undergo [3 + 3] cyclodimerization of the B-C=N chain to give the tricyclic products 6a, b when isonitriles RNC with the small ligands R = Me, Et are boroborated by 1. Two molecules of tBuNC open the B-B bond of 1; the resulting five-membered ring 7a may add excess tBuNC to yield 7a · 2 CNtBu (8). The results strongly support a mechanistic hypothesis set up for the multistep reaction of 1 and CO. The carbene units, which are present in the α-bromolithioalkanes [-C(Br)Li-CMe2-CH2-], LiC(Br)H2, and LiC(Br)Me2, are also 1,1-boroborated by 1 to give the corresponding four-membered ring 2c, or by a 2:1 reaction to afford the five-membered ring 7b, or by a 1:1 reaction and subsequent rearrangement to yield the five-membered ring 7c. The nitrene units, which are present in the azides PhN3 and PhCH2N3, are also boroborated by 1; the diazadiboretidines 5b, c are formed with evolution of N2. The bis(diazadiboretidinyl)borane RB(N2B2R3)2 (5d) is the corresponding product from the reaction of RB(N3)2 with 1 in the ratio 1:2. The azide Me3SiN3 reacts differently yielding the N-boryl diazadiboretidine 5e and the iminoborane RB≡N̊. The B-B bond length of 187.6 pm in 5e indicates a transannular bonding interaction. The products 5d, 5e, and 6a were characterized by a crystal structure analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951281011
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  • 9
    Electronic Resource
    Electronic Resource
    (Iminoboryl)borate [R3B—B≡NR]-: Durch Elektrophile E induzierte Umlagerung zu (Aminoboryl)boranen R2B—BR=NRE (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 361-365 
    Details
    ISSN: 0009-2940
    Keywords: (Iminoboryl)borates ; (Aminoboryl)boranes ; Trialkyl(amino)diboranes(4) ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Iminoboryl)borates [R3B—B=NR]-: Rearrangement to (Aminoboryl)boranes R2B—BR=NRE by the Addition of Electrophiles E(Iminoboryl)borates [Li(tmeda)2][R2R′B-B≡NR (2a-c, R′ = Me, Me3SiCH2, Me3CCH2) are formed from the azadiboriridine NB2R3 (1, R = tBu) and LiR′ in the presence of tmeda. Vinyllithium brings about a ring expansion of 1 to give the five-membered anionic ring [-CH=CH-BR=NR-BHR-]-, to which [Li(tmeda)]+ is bound (3). The (aminoboryl)boranes R2B-BMe=NER (4a-c, EX = HCl, MeI, Me3SiI) are obtained, when the polar compounds EX are added to 2a, accompanied by the elimination of LiX and the migration of Me. The borate 2b reacts with HCl to give a mixture of the isomers R2B-B(CH2SiMe3)=NHR (4d) and R(Me3SiCH2)-B-BR=NHR (4d′), and 2c reacts with HCl to yield the borane R(Me3CCH2)B-BR=NHR (4e′) exclusively. The transformation of [R2R′B-B=NR]- to R2B-BR′ = NRE by the attack of electrophiles E corresponds to the known transformation of [R′3B-C≡R″] to R′2B-CR′=CR″E.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961290318
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  • 10
    Electronic Resource
    Electronic Resource
    Polare Iminoborane: Reaktionen des (tert-Butylimino)(pentafluorphenyl)borans (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1037-1043 
    Details
    ISSN: 0009-2940
    Keywords: Iminoborane ; Triazadiboracyclohexane ; Borazine ; Diazadiboracyclobutane ; Azaboracyclobutane ; Diazadiboracyclopentane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polar Iminoboranes: Reactions of (tert-Butylimino)(pentafluorophenyl)boraneThe reactions of the iminoborane C6F5-B≡N-tBu (1) with nitriles and isonitriles are studied. Nitriles RCN give cycloadducts either of the triazadiboracyclohexane type (3a; R = iPr) or of the tetrazatriborabicyclo[4.2.0]octane type [4b-d; R = Ph, p-C6H4Me, p-C6H4(CF3)] or of the (iminomethyl)borazine type (5e, f; R = Me, Et). Isonitriles RNC yield mainly adducts of RNC to a cycloaddition product of the diazadiboracyclopentane type (6a, b; R = 2,6-C6H3Me2, tBu); the adduct of RNC to a diazadiboracyclobutane may be a side-product (7b; R = tBu). The iminoborane Me3Si(tBu)N-B=NtBu reacts with two molecules of (2,6-C6H3Me2)NC to give the corresponding azaboracyclobutane 8. The iminoborane tBu-B≡N-C6F5 (1′), formed by gas-phase elimination of ClSiMe3 from Cl(tBu)B = N(C6F5)SiMe3 (9), cyclodimerizes more readily than the isomeric borane 1. The cyclodimer 2′ gives 1:1-addition reactions with tBuNC, PMe3, and MeNC, respectively; the added components fluctuate in solutions of the products 7b'-d'. A similar fluctuation is observed with the 1:1 adduct 7c from PMe3 and the cyclodimer 2 of the iminoborane 1. The products 3a, 5e, 6a, 8 crystallize in the space groups P21/c, P21/n, Pbca, and P21/c, respectively.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951281012
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