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  • 1
    Electronic Resource
    Electronic Resource
    The photoelectron spectrum and conformation of phenylphosphine and phenylarsine (1995)
    Springer
    Structural chemistry 6 (1995), S. 1-7 
    Details
    ISSN: 1572-9001
    Keywords: UV photoelectron spectroscopy ; ab initio quantum-chemical calculations ; phenylphosphine ; phenylarsine ; o-phosphinophenol ; o-arsinoaniline ; conformation ; rotational barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract He(I) and He(II) photoelectron spectra of phenylphosphine and phenylarsine have been investigated and assigned. The rotational barrier of the phosphino group has been investigated at the MP2/6-31G(d,p)//MP2/6-31G(d,p) and HF/6-31G(d,p)//HF/6-31G(d,p) levels of theory, and that of the arsino group at the HF/6-31G(d,p)//6-31G(d,p) levels of theory. The rotational barrier of the two molecules is nearly the same. The energy difference between the two possible conformers of the molecules is low (1.5 kJ/mol at the MP2/6-31G(d,p) level of theory), allowing nearly free rotation about the P-C bond. The photoelectron spectrum cannot be interpreted by considering the most stable rotamer, but all possible conformers should be taken into account. The present interpretation is consistent with the smalln p - π interaction concluded from other investigations. The rotational barrier ofo-phosphinophenol is significantly larger than for phenylphosphine, and the photoelectron spectrum of this compound can be interpreted by considering a single conformer, and no appreciable interaction between the π-system of the ring and the phosphorus lone pair.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02263522
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  • 2
    Electronic Resource
    Electronic Resource
    Complexes of Azaphospholes: Synthesis and Structure of Pentacarbonyl-(η1)-2-phosphaindolizine)chromium(0), -molybdenum(0), and -tungsten(0) (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1079-1086 
    Details
    ISSN: 1434-1948
    Keywords: Phosphorus heterocycles ; P ligands ; Transition metals ; Carbonyl complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complex chemical behaviour of 2-phosphaindolizines 1 (1,3-azaphospholo[1,5-a]pyridines) towards metal carbonyl compounds was studied. (η1-2-Phosphaindolizine)M(CO)5 complexes 2-4 (M = Cr, Mo, W) were formed from 1 and [(THF)M(CO)5], the cis-L2Cr(CO)4 complex 5f from 1f and tetracarbonyl(norbornadiene) chromium(0). The reaction of 2-phosphaindolizines 1e, 1f, or 1g with tricarbonyl(cycloheptatriene)molybdenum(0) or tricarbonyl(mesitylene)tungsten(0) yielded σ-complexes of the types L2M(CO)4or L3M(CO)3 rather than isolable π-complexes. In one case a strong upfield signal (δ31P = 6.1) was observed with a coordination shift of Δδ = -161.7, which is typical for π-coordination. Prolonged reaction or work-up led, however, to dismutation yielding 1g and the fac-L3Mo(CO)3 complex 6g. X-ray structure analysis of 2a indicates an increased 10π-delocalization compared with 1a and a changed conformation of the acyl substituent. The influence of substituents and metals on the 31P and 13C complexation chemical shifts and coupling constants is discussed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Sterically stressed amino- and PH-functional di-t-butyl-o-phosphinophenols - Intramolecular interaction and formation of benzoxadiphospholes (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 9 (1998), S. 183-193 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lithium and sodium o-lithio-4,6-di-t-butyl-phenolates 1 and 2 react, successively, with ClP(NMe2)2 and ClSiMe3 to give 2-(Me2N)2P-4,6-t-Bu2C6H2OSiMe3 3. 1 and ClP(NMe2)Ph furnish a small amount of the analogous compound 4 but mainly diastereoisomers of a C, O-diphosphinylation product 5A/B, which exhibit large through-space coupling constants (4JPP = 152 and 237.5 Hz). Under certain conditions, the P-N bond is attacked, and triphosphines 6 and 7 are formed. Alcoholysis of 3-5 and subsequent reduction with LiAlH4 yields the respective bulky primary and secondary phosphinophenols 8 and 9. Both decompose partially on distillation, affording tBu2C6H3OH and the cyclic diphosphines 10 and 11. 10, a further dihydro-benzoxadiphosphol 13 and a phosphinidene-phosphorane 14 are formed by reaction of 8 with P(NMe2)3. The molecular structure of bicyclic 10, folded at the P-P bond, is reported. The uncommon features - unselective disubstitution of 1, P…P interactions in 5 and 6, facile P-C cleavage of 8 and 9, and diphosphine formation - reveal a dramatic influence of the bulky substituents in the 6-position on the chemistry of 2-phosphinophenols. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:183-193, 1998
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    P/O ligand systems: Synthesis and reactivity of primary and secondary o-phosphinophenols (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 8 (1997), S. 383-396 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several organometallic reagents such as lithium 2-lithio 4-methylphenolate 1 intermediates formed by orthometallation of o-bromoaryloxy-phosphorus(V)- 2 or -phosphorus(III)-derivatives 3 with magnesium and sodium, respectively, as well as O-methoxymethyl-protected o-lithio-4-methylphenol 4 were used to synthesize suitable precursors 5,6,9,10 of primary and secondary o-phosphinophenols. The P-C bond formation involved coupling with ClPR(NMe2), CIPR(O)(OEt) or an intramolecular carbanionic O → C shift of the P-substituent. Reduction with LiAlH4, in the cases of phosphonous or phosphinous acid amides after alcoholysis (to 7,8,11), produced primary and secondary o-phosphinophenols 12, respectively, or O-protected derivatives 13. o-Phosphinophenols 12 are easily protonated at the phosphorus atom, supported by a P+-H … O hydrogen bridge. Metallation (14), acylation, and silylation (16,17) take place preferably at the hyxdroxy group and alkylation at the phosphorus atom. Alkylation of 12 and 14 was found to be slow, but C,O-dilithiated species 15 react to give P-secondary (12b,d,e,) or P-tertiary products (20,21). Cyclization of 15a with Me2SiCl2 affords the 2,3-dihydro-1,3,2-benzoxaphosphasilol 22, cyclocondensation of 12c with RP(NMe2)2 or ClP(NMe2)2 furnishes 2,3-dihydro-1,2,3- benzodiphospholes 23 and 24. A phosphiniden-phosphoran 25 is detected in the reaction between 12a and P(NMe2)3. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 383-396, 1997
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    2-phosphaindolizines (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 9 (1998), S. 333-339 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eight new 2-phosphaindolizines 2 have been obtained by [4 + 1] cyclocondensation of 1,2-dialkylpyridinium halides 1 with PCl3. The X-ray structure analysis of 2a is consistent with the integration of the 1,3-azaphosphole ring in the 10π-aromatic system. The charge densities on phosphorus of various representatives as obtained by PM3 calculations correlate approximately with the 31P-NMR shifts. The mass spectral fragmentation of 2a resembles that of its nonphosphorus analog. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:333-339, 1998
    Additional Material: 1 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Methoxymethylsilylene: (1 + 6)- and (1 + 4)-cycloadditions to heterotrienesDedicated to Prof. Dr. K. Rühlmann (dresden) on the occasion of his sixty-fifth birthday. (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 6 (1995), S. 461-468 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Co-pyrolytic gas phase reactions of 1,2-dimethyl-1,1,2,2-tetra-(methoxy)disilane with conjugated 1-oxatrienes in a flow-reactor furnish, via intermediate methoxymethylsilylene, mixtures of diastereoisomers of 3-phenyl-1-oxa-2-silacyclohepta-4,6-dienes and 3-styryl-1-oxa-2-silacyclopent-4-enes, usually including smaller amounts of the corresponding 1-oxa-2-silacy-clopent-3-ene isomers. In co-pyrolysis with an analogous N-isopropylazatriene, five-membered rings were formed preferentially, and seven-membered isomers could not be detected by NMR spectroscopy. © 1995 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520060511
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  • 7
    Electronic Resource
    Electronic Resource
    Aminosubstituted disilanes: Synthesis by unsymmetrical and symmetrical reductive coupling (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 9 (1998), S. 311-316 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reductive coupling of chlorotris(diorganylamino)silanes 1 with chlorotrimethylsilane by the action oflithium in THF provides for steric reasons, an easy access to unsymmetrical aminosubstituted disilanes (R2N)3Si-SiMe3 3. Similarly, cross-coupling to give pentakis(diethylamino)disilane 4 is observed between 1a and bis(diethylamino)chloro-hydridosilane 2a on treatment with lithium. In reactions of the less bulky bis(diorganylamino)chlorohy-dridosilanes 2 with ClSiMe3 and Li, however, thesymmetrical coupling is preferred and affords SiH-functional substituted (R2N)32HSi-SiH(NR2)2 5. Aminosubstituted disilanes 3-5 are useful starting materials for modification of disilanes or syntheses ofsilicon heterocycles via generation and trapping of aminosilylenes, as exemplified by diethylaminosilacyclopent-3-ene 6a. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:311-316, 1998
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  • 8
    Electronic Resource
    Electronic Resource
    Higher carbene homologues: Naphtho[2,3-d]-1,3,2λ2-diazagermole, -diazastannole, and attempted reduction of 2,2-dichloronaphtho[2,3-d]-1,3,2-diazasiloleDedicated to Prof. Heinrich Nöth on the occasion of his seventieth birthday. (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 9 (1998), S. 439-444 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N,N′-Dineopentyl-2,3-diaminonaph-thalene 1, obtained by reaction of 2,3-diaminonaph-thalene with pivaloyl chloride and subsequent re-duction, was dilithiated and cyclodisubstituted with SiCl4 to give dichloro-dineopentyl-naphtho[2,3-d]-1,3,2-diazasilole 2. Treatment of 2 with two equivalents of potassium in THF caused cleavage of the Si-N ring. A silylene could not be detected. The corresponding cyclic diaminogermylene 3 and diamino-stannylene 4 were obtained by direct ring closure of 1-Li2 with GeCl2·dioxane or SnCl2, respectively. The compounds are structurally characterized by NMR and MS. The properties of 3 and 4 are compared with those of related germylenes and stannylenes. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:439-444, 1998
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  • 9
    Electronic Resource
    Electronic Resource
    P/O Ligand Systems: Synthesis, Reactivity, and Structure of Tertiary o-Phosphanylphenol Derivatives (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 431-431 
    Details
    ISSN: 0009-2940
    Keywords: o-Phosphanylphenols ; P,O hybrid ligands ; P asymmetry ; C,O-dilithium reagents ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300320
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  • 10
    Electronic Resource
    Electronic Resource
    P/O Ligand Systems: Facile Synthesis, Structure, and Catalytic Tests of 2′-Phosphanyl-1,1′ -phenyl-2-ols and 2′-Phosphanyl-1,1′-binaphthyl-2-ols (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1663-1670 
    Details
    ISSN: 0009-2940
    Keywords: Lithiation ; P ligands ; NMR spectroscopy ; Molecular structure ; Hydrogenations ; Hydroformylations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A facile synthesis of 2′-phosphanyl-1,1′-biphenyl- and 2′-phosphanyl-1,1′ -binaphthyl-2-ols and their silyl ethers has been developed, consisting of electron-transfer-catalyzed ring-opening of dibenzofuran and dinaphthofuran, respectively, subsequent reaction with chlorophosphanes, and work-up with acetic acid or ClSiMe3. Studies of the molecular and crystal structures reveals the presence of P - H - O bridging bonds in the more basic tBuPhP derivative and a nearly perpendicular arrangement of the aryl planes in the biphenyl derivatives. The barrier to rotation of the aryl planes about the C-C axis was determined by NMR in the case of the P-asymmetric derivative 3d, using the appearence of diastereoisomers by atropisomerism and P-asymmetry. Comparative screening tests of the title compounds, phosphanyl phenols and phosphanylnaphthols in homogeneous Rh-catalyzed reactions demonstrate catalytic activity in hydroformylation reactions and superior properties of the biphenyl- and binaphthyl-2-ol derivatives in relation to other P-O ligands.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971301118
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