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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2355-2368 
    ISSN: 1434-1948
    Keywords: Phosphane complexes ; Lithium ; Aminophosphanes ; Hydrazides ; (N-lithioamino)diorganophosphanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Butyllithium (nBuLi) deprotonates Ph2P-NHtBu in ether to give (Ph2P-NLitBu)2·OEt2. There is no Li···P interaction in this molecule. Three compounds of the type R′P(NLiR)2 have been obtained by lithiation of R′P(NHR)2, isolated as [BuP(NLitBu)2·OEt2]2, [PhP(NLiPh)2·OEt2]2 and [PhP(NLiPh)2]2. Reaction of nBuLi with MeP(NHiPr)2 in hexane/THF leads to [MeP{N(Li)iPr]2·THF}4 with an asymmetric cluster structure comprising one LiP3, three LiPN2, three LiP2N and one LiN3 cluster units. The molecular structures of these compounds as determined by X-ray structure analysis show that they are best depicted as N-lithioaminophosphanes and not as the isomeric P-lithioiminophosphoranes.
    Additional Material: 13 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1373-1379 
    ISSN: 1434-1948
    Keywords: Sodium bis(borane)dimethylamide solvates ; X-ray structure ; Reduction ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of sodium metal with dimethylamine-borane in THF yields Na[(H3B)2NMe2] (1) which can be isolated as {Na[(H3B)2NMe2]}5·THF or as Na[(H3B)2NMe2]·15-crown-5 (2) and Na[(H3B)2NMe2]·benzo-15-crown-5 (3) after addition of the appropriate crown ether to the THF solution of 1. Reaction of 1 with ZrCl4 yields Me2HN-BH2-NMe2-BH3 (4), the structure of which has been determined. In THF solution, 1 reduces aldehydes, ketones, acyl chlorides, and esters to the corresponding alcohols. It also reacts slowly with nitriles and allylbenzene. Compound (1)5·THF crystallizes in an extended three-dimensional lattice, in which the Na atoms are coordinated by 6-9 hydridic H atoms, while 3 is a molecular compound in the solid state. Only one hydrogen atom of each BH3 group coordinates to the sodium center. On the other hand, 4 forms dimeric associates in the solid state through N-H···H-B interactions.
    Additional Material: 6 Ill.
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  • 3
    ISSN: 1434-1948
    Keywords: Aluminium ; Amides ; Calcium ; Metallacycles ; Phosphorus ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of calcium bis[bis(trimethylsilyl)amide] with two equivalents of tris(trimethylsilylmethyl)alane yields (Me3SiCH2)2Al-N(SiMe3)2 (1) and the dimer [(Me3Si)2N-Ca(μ-CH2SiMe3)2Al(CH2SiMe3)2]2 (2). The five-coordinate bridging carbon atoms show Ca-C bond lengths of 264 and 268 pm. A similar reaction with calcium bis[bis(trimethylsilyl)phosphanide] gives the dimer [(Me3SiCH2)2Al-P(SiMe3)2]2 (3) with crystallographic C2 symmetry. A calcium-containing species is not isolable, however, in the presence of DME - ether cleavage reactions and the formation of the centrosymmetric dimer [(Me3SiCH2)2Al-OCH2CH2OMe]2 (4) are observed. The central moiety is an Al2O2 cycle with fivefold coordinated aluminium centers.
    Additional Material: 4 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2215-2220 
    ISSN: 1434-1948
    Keywords: Magnesium ; Metalation ; Phosphorus ; Polyhedra ; X-ray structures ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The magnesiation of triisopropylsilylphosphane with dibutylmagnesium in toluene yields the octanuclear complex [Mg8(PSiiPr3)6{P(H)SiiPr3}4] (1) which consists of MgPSiiPr3 units forming a hexagonal Mg6P6 prism, with two opposite Mg2P2 moieties capped by additional Mg[P(H)SiiPr3]2 groups. If a small amount of THF is present during the metalation reaction [(THF)4Mg6(PSiiPr3)6] (2) also containing a hexagonal Mg6P6 prism can be isolated. The magnesiation of H2P-SiiPr3 in tetrahydrofuran leads to the formation of the tetrameric complex [(THF)MgPSiiPr3]4(3) with a slightly distorted Mg4P4 cubane-like structure.The structures depend strongly on the steric strain caused by the trialkylsilyl substituents and the neutral coligands at the magnesium center. The highest steric strain, which is induced by coordination to every magnesium atom, leads to the smallest MgnPn polyhedron - the central Mg4P4 heterocubane moiety. In compounds 1 and 2 the hexagonal Mg6P6 prism is formed, however, with reduced steric strain as observed for 2 where the Mg-P bond lengths become more similar.
    Additional Material: 4 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1291-1293 
    ISSN: 1434-1948
    Keywords: Aluminum ; Lead ; O ligands ; Alkoxy carboxylates ; Structure elucidation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel heterometallic aggregate Pb2Al5(μ3-O)(μ4-O)(μ-OiPr)9(OiPr)3(μ-OAc)3 obtained from the interaction of Pb(OAc)2 and Al(O-iPr)3 is the first structurally characterized example based on lead and aluminum. This compound has been isolated in high yield and examined by 1H-, 13C-, and 27Al NMR, and in the solid state by X-ray crystallography.
    Additional Material: 2 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 121-125 
    ISSN: 0947-3440
    Keywords: Propargyl rearrangement ; DBU ; Electrocyclization ; Diphosphaquinone ; Dihydrodiphosphete ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: o-Quinodimethanes 1 are important intermediates in organic synthesis that may be generated by thermal valence isomerization of benzocyclobutenes[1] or octa-1,2,4,6,7-pentaenes[2]. The preparation of a stable o-quinodimethane has not been reported so far. Whereas o-quinodiimines 2 containing strongly electron-withdrawing groups at the nitrogen atoms are isolable[3], o-diphosphaquinones 3 have not been detected.
    Additional Material: 2 Ill.
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  • 7
    ISSN: 0947-3440
    Keywords: 1,2-Dithiin ; Cycloadditions ; Sulfur extrusion ; Thiophenes ; Reaction mechanisms ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetracyanoethylene combines with two molecules of thiobenzophenone in refluxing benzene to give the tetrasubstituted 1,2-dithiin 8 (21-29%) besides the corresponding thiophene derivative 9 (40-52%). The X-ray analysis of the ruby-red 8 reveals a half-chair conformation with a torsion angle of 58.9° at the disulfide bond. The thermal desulfurization 8 → 9 (benzonitrile, 100°C) proceeds with t1/2 = 26.7 h, whereas the sulfur loss induced by triethyl phosphite is a billion times faster. The mechanisms of the formation of 8 and its sulfur extrusion are discussed in the light or recent literature.
    Additional Material: 2 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 221-227 
    ISSN: 0947-6539
    Keywords: heterocycles ; organic syntheses ; phospholes ; phosphorus ylides ; ring expansions ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Condensation of a 1,3-diphosphoniopropenide cation at its reactive 1,3-positions with a dichlorophosphine in the presence of triethylamine provides a route to 2,4-diphosphoniodihydrophosphetide cations. An excess of dichlorophosphine in the presence of an additional reducing agent results in a ring expansion and yields 3,5-diphosphoniodihydro-1,2-diphospholide cations. The chlorosubstituted cation derived from PCl3 can be further reduced to the hydrolytically stable 3,5-diphosphonio-1,2-diphospholide cation. It adds halogen to the P=P bond and can easily be regained from the halogen adduct. Structural comparison of the 1,2-diphenyl- and 1,2-dichlorodihydro-1,2-diphospholide cation with the 1,2-diphospholide cation shows three stages of interaction of the C3 and the P2 entities of the ring: no conjugation in the first case, hyperconjugative extension of the allylic system to include the phosphorus atoms in the second case and cyclic π conjugation in the third.
    Additional Material: 5 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 2377-2382 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Aminoborierung von CO2 und CS2 nach zu Carbamoyloxy- und Thiocarbamoylmercapto-boranen ist vor allem eine Funktion der Basizität des Aminoborans. Sterische Faktoren spielen bei der Aminoborierung von CS2 eine größere Rolle als bei der von CO2.
    Additional Material: 4 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 100 (1967), S. 2899-2907 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus (diphos)2CoH (diphos=(C6H5)2P—CH2—CH2—P(C6H5)2, o—C6H4[P(CH3)2]2) und R2BCI (R2B = (C6H5)2B bzw. 9-Bora-fluorenyl) entstehen unter Wasserstoffentwicklung (diphos)2 und trans-(diphos)2Co(BR2)2. Die Diphenylbor- bzw. 9-Bora-fluorenyl-Gruppe ist Träger negativer Ladung. Sie läßt sich durch Ligandenaustauschreaktion übertragen, wie die Synthese von Verbindungen mit Fe—B-, Mn—B-, Ni—B- und Au—B-Bindung zeigt.
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