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Papers by Burkhard Carlsohn

Chemischer Informationsdienst, May 23, 1978

Chemischer Informationsdienst, 1978

Chemische Berichte, 1978

Contributions to the Chemistry of Phosphorus, 78: 1,2,3-Triphenyltriphosphane Among the dispropor... more Contributions to the Chemistry of Phosphorus, 78: 1,2,3-Triphenyltriphosphane Among the disproportionation products of 1,2-diphenyldiphosphane (1), 1,2,3-triphenyltriphosphane (2) could be enriched up to the maximum concentration of ≈50% with respect to the total phosphorus. 2 was identified by the 31P{1H} NMR spectrum that exhibits, in the region of openchain triphosphanes, two A2B and one ABC spin system for the three diastereomers, of which the NMR parameters are reported. Contrary to results given in the literature, 2 is not stable at room temperature, but disproportionates to give lower and higher homologues of the series H(PPh)nH as well as cyclic phenylphosphanes, especially (PPh)5.

Chemische Berichte, 1980

Die Reaktion von 1,3-Dikaliurn-l,2,3-triphenyltriphosphid, K,(PPh),, mit Chlortrimethylsilan ergi... more Die Reaktion von 1,3-Dikaliurn-l,2,3-triphenyltriphosphid, K,(PPh),, mit Chlortrimethylsilan ergibt in guter Ausbeute die bislang unbekannte Titelverbindung Me,Si(Ph)P-P(Ph)-P(Ph)SiMe, (l), die gegenuber Disproportionierungsreaktionen bemerkenswert bestandig ist. Sie bildet in Losung die drei Diastereomeren 1 a (erythrolerythro), 1 b (erytliro/tkreo) und l c (t/treo/lhreo) im Verhiltnis von etwa 8: 3: 1, die infolge pyramidaler Inversion der P-Atome in einem dynamischen Gleichgewicht miteinander stehen. Die Korrelation zwischen den 3 ' P-NMR-spektroskopisch beobachteten Spinsystemen und den Diastereonieren 1 a-c ergibt sich aufgrund der signifikanten Torsionswinkelabhangigkeit der ' J ,,-Kopplungskonstanten. Die bevorzugte trans-Anordnung der groholumigen SiMe,-und P(Ph)SiMe,-Reste an benachbarten P-Atomen fiihrt bei erythro-Konfiguration zu einer trans-und bei threo-Konfiguration zu ciner gauche-Konformation der freien Elektronenpaare. Contributions to the Chemistry of Phosphorus, 88'3') 1,2,3-Triphenyl-1,3-bis(trimethylsilyl)triphosphane The reaction of 1,3-dipotassium 1,2,3-triphenyltriphosphide, KJPPh),, with chlorotrimethylsilane yields the hitherto unknown title compound Me,Si(Ph)P-P(Ph)-P(Ph)SiMe, (l), which is remarkably stable against disproportionation reactions. In solution it forms the three diastereomers l a (eryt/rro/rryt/irc,), lb(erythro/threo), and l c (rllreo/th~~eo) in a ratio ofabout 8:3:1, between which a dynamic equilibrium exists due to pyramidal inversion at the P-atoms. The correlation between the 'P-NMR-spectroscopically observed spin systems and the diastereomers 1 ac results from the significant dependence of the ' J ,,,,-coupling constants on dihedral angles. The preferred trans arrangement of the bulky %Me,-and P(Ph)SiMe, groups at adjacent P-atoms leads to a trans-conformation of the lone electron pairs in the cvythro-and to a gauclze-conformation in the threo-configuration. Vor einigen Jahren konnte als erstes silyliertes Diphosphanderivat 1,2-Diphenyl-1,2-bis(trimethylsilyl)diphosphan, Me,Si(Ph)P-P(Ph)SiMe,, durch Trimethylsilylierung von 1,2-Dikaliuni-1,2-diphenyldiphosphid dargestelli werden"'. lnzwischen haben die davon ausgehenden Synthesen von 1,2-Diphenyldiphosphan, H(Ph)P-P(Ph)H '1, und von Triphenylcyclotriphosphan, [PPh], '), die allgemeine praparative Bedeutung der partiell silylierten kettenformigen Organylphosphane gezeigt. Im Rahmen unserer Untersuchungen iiber Phenylphosphane offenkettiger und cyclischer Struktur 4-') war das noch unbekannte 1,2,3-Triphenyl-1,3-bis(trimethylsilyl)triphosphan (1) von besonde

Zeitschrift für Naturforschung B, 1976

The weak resonances at + 22 and + 49 ppm appearing in the 31P NMR spectrum of melts or solutions ... more The weak resonances at + 22 and + 49 ppm appearing in the 31P NMR spectrum of melts or solutions of (PPh)5 that have been attributed previously in the literature to “dimeric” and “monomeric phenylphosphorus” are caused by (PPh)6 and (PPh)4, respectively. This was proved by comparison with the 31P NMR parameters of related compounds and by 31P NMR spectroscopic investigation of authentic samples of (PPh)6 and (PPh)4, the latter of which was prepared in high yield from (Me3Si)PhP–PPh–PPh(SiMe3) and PhPCl2. (PEt)4 and mixed-substituted phenyl-ethyl-cyclotetraphosphanes exhibit similar chemical shifts as (PPh)4, corresponding mixed-substituted cyclohexaphosphanes have similar chemical shifts as (PPh)6. Generally, cyclophosphanes establish an equilibrium between (PR)n-species of different ring-size. Probably, the ring-interconversion proceeds via a multi-center mechanism. No 31P NMR spectroscopic evidence for the existence of free PPh or P2Ph2 under the conditions described could be dete...

Chemischer Informationsdienst

Chemischer Informationsdienst

Zeitschrift f�r anorganische und allgemeine Chemie, 1977

Bei der Reaktion von (CH3)3Si(C6H5)PP(C6H5)Si(CH3)3 mit RPCl2 (R = C6H5, C2H5, CH3) werden die Cy... more Bei der Reaktion von (CH3)3Si(C6H5)PP(C6H5)Si(CH3)3 mit RPCl2 (R = C6H5, C2H5, CH3) werden die Cyclotriphosphane (PC6H5)31 bzw. (PC6H5)2(PC2H5) 3 bzw. (PC6H5)2(PCH3) 4 gebildet. Daneben entstehen die entsprechenden einheitlich- bzw. gemischtsubstituierten Cyclotetraphosphane, Cyclopentaphosphane und Cyclohexaphosphane. Der Anteil der Cyclotriphosphane im Reaktionsgemisch nimmt fortlaufend ab, wahrend derjenige der Cyclopentaphosphane ansteigt. Die Ursachen dieser Ringumlagerungen von Cyclophosphanen (PR)n werden diskutiert. Die Cyclotriphosphane 1, 3 und 4 sind im 31P-NMR-Spektrum durch chemische Verschiebungen im Bereich von +130 bis +160 ppm charakterisiert und zeigen damit eine starke Hochfeldverschiebung gegenuber offenkettigen Triphosphanen und Cyclophosphanen anderer Ringgrose. Die Substituenten R sind auf beiden Seiten der P3-Ringebene angeordnet, so das fur 3 zwei mogliche Diastereomere resultieren, die in dem statistisch zu erwartenden Populationsverhaltnis nebeneinander vorliegen. Die 31P-NMR-Parameter fur 1 und 3 werden mitgeteilt und diskutiert. Contributions to the Chemistry of Phosphorus. 67. About the Cyclotriphosphanes (PC6H5)3, (PC6H5)2(PC2H5), and (PC6H5)2(PCH3) The reaction of (CH3)3Si(C6H5)PP(C6H5)Si(CH3)3 with RPCl2 (R = C6H5, C2H5, CH3) yields the cyclotriphosphanes (PC6H5)31, (PC6H5)2(PC2H5) 3, and (PC6H5)2(PCH3) 4, respectively. Besides, the corresponding homo- and mixed-substituted cyclotetraphosphanes, cyclopentaphosphanes, and cyclohexaphosphanes are formed. The relative concentrations of the cyclotriphosphanes in the reaction mixtures decrease continuously, whereas those of the cyclopentaphosphanes increase. The reasons for these ring-interconversion reactions of the cyclophosphanes (PR)n are discussed. The cyclotriphosphanes 1, 3, and 4 are characterized by 31P chemical shifts between +130 and +160 ppm that are at considerable high field compared to open-chain triphosphanes and cyclophosphanes of different ring-size. The substituents R are situated on both sides of the P3-ring plane, thus giving rise to two diastereomers of 3 that are observed simultaneously in the statistically expected ratio. The 31P n.m.r. parameters of 1 and 3 are reported and discussed.

Chemischer Informationsdienst, 1980

1,2-Diphenyldiphosphan (1) wird - entgegen Literaturangaben - bei der Reaktion von KHPPh mit 1,2-... more 1,2-Diphenyldiphosphan (1) wird - entgegen Literaturangaben - bei der Reaktion von KHPPh mit 1,2-Dibromethan gebildet. Reines 1 ist durch Hydrolyse oder Alkoholyse von Me3Si(Ph)P - P(Ph)SiMe3 unter Lichtausschlus erhaltlich und bei − 30°C bestandig. Es disproportioniert bei Raumtemperatur in PhPH2, hohere Homologe der Reihe H2[PPh]n — insbesondere H2[PPh]3 - und cyclische Phenylphosphane [PPh]n — vor allem [PPh]5. Diese Umlagerungen werden durch Licht, Phosphide sowie starke Sauren und Basen beschleunigt. Mit K(Ph)PP(Ph)K, Me3Si(Ph)PP(Ph)SiMe3 oder P2Ph4 reagiert 1 zu den unsymmetrischen Diphosphanen K(Ph)PP(Ph)H, Me3Si(Ph)PP(Ph)H bzw. Ph2PP(Ph)H. Die NMR-, IR- und Raman-Spektren von 1 werden diskutiert. Contributions to the Chemistry of Phosphorus, 73: 1,2-Diphenyldiphosphane 1,2-Diphenyldiphosphane (1) is formed, contrary to results given in the literature, by the reaction of KHPPh with 1,2-dibromoethane. Pure 1 is obtained by hydrolysis or alcoholysis of Me3Si(Ph)P-P(Ph)SiMe3 in ...

1,2 - Diphenyl - 3,3 - dimethyl - diphosphirane (1,2- Diphenyl- 3,3- dimethyl-diphosphacyclopropa... more 1,2 - Diphenyl - 3,3 - dimethyl - diphosphirane (1,2- Diphenyl- 3,3- dimethyl-diphosphacyclopropane) (1) is formed by the reaction of K(C6H5)P–P(C6H5)K with 2,2-dichloropropane in n-pentane at —30 °C. It could be detected and identified by its 31P NMR singlet at —122 ppm, which lies in the high field region characteristic for phosphorus three-membered ring compounds, as well as by its mass spectrum. Besides, (PC6H5)5 and several cyclocarbaphosphanes of ring sizes five and six are formed. After the reaction of (CH3)3Si(C6H5)P–P(C6H5)Si(CH3)3 with methylene iodide a weak 31P NMR signal at —147 ppm could be observed, which probably corresponds to the 1,2-diphenyl-diphosphirane.

Zeitschrift für Naturforschung B

1,2 - Diphenyl - 3,3 - dimethyl - diphosphirane (1,2- Diphenyl- 3,3- dimethyl-diphosphacyclopropa... more 1,2 - Diphenyl - 3,3 - dimethyl - diphosphirane (1,2- Diphenyl- 3,3- dimethyl-diphosphacyclopropane) (1) is formed by the reaction of K(C6H5)P–P(C6H5)K with 2,2-dichloropropane in n-pentane at —30 °C. It could be detected and identified by its 31P NMR singlet at —122 ppm, which lies in the high field region characteristic for phosphorus three-membered ring compounds, as well as by its mass spectrum. Besides, (PC6H5)5 and several cyclocarbaphosphanes of ring sizes five and six are formed. After the reaction of (CH3)3Si(C6H5)P–P(C6H5)Si(CH3)3 with methylene iodide a weak 31P NMR signal at —147 ppm could be observed, which probably corresponds to the 1,2-diphenyl-diphosphirane.

Chemischer Informationsdienst

Chemischer Informationsdienst, May 23, 1978

Chemischer Informationsdienst, 1978

Chemische Berichte, 1978

Contributions to the Chemistry of Phosphorus, 78: 1,2,3-Triphenyltriphosphane Among the dispropor... more Contributions to the Chemistry of Phosphorus, 78: 1,2,3-Triphenyltriphosphane Among the disproportionation products of 1,2-diphenyldiphosphane (1), 1,2,3-triphenyltriphosphane (2) could be enriched up to the maximum concentration of ≈50% with respect to the total phosphorus. 2 was identified by the 31P{1H} NMR spectrum that exhibits, in the region of openchain triphosphanes, two A2B and one ABC spin system for the three diastereomers, of which the NMR parameters are reported. Contrary to results given in the literature, 2 is not stable at room temperature, but disproportionates to give lower and higher homologues of the series H(PPh)nH as well as cyclic phenylphosphanes, especially (PPh)5.

Chemische Berichte, 1980

Die Reaktion von 1,3-Dikaliurn-l,2,3-triphenyltriphosphid, K,(PPh),, mit Chlortrimethylsilan ergi... more Die Reaktion von 1,3-Dikaliurn-l,2,3-triphenyltriphosphid, K,(PPh),, mit Chlortrimethylsilan ergibt in guter Ausbeute die bislang unbekannte Titelverbindung Me,Si(Ph)P-P(Ph)-P(Ph)SiMe, (l), die gegenuber Disproportionierungsreaktionen bemerkenswert bestandig ist. Sie bildet in Losung die drei Diastereomeren 1 a (erythrolerythro), 1 b (erytliro/tkreo) und l c (t/treo/lhreo) im Verhiltnis von etwa 8: 3: 1, die infolge pyramidaler Inversion der P-Atome in einem dynamischen Gleichgewicht miteinander stehen. Die Korrelation zwischen den 3 ' P-NMR-spektroskopisch beobachteten Spinsystemen und den Diastereonieren 1 a-c ergibt sich aufgrund der signifikanten Torsionswinkelabhangigkeit der ' J ,,-Kopplungskonstanten. Die bevorzugte trans-Anordnung der groholumigen SiMe,-und P(Ph)SiMe,-Reste an benachbarten P-Atomen fiihrt bei erythro-Konfiguration zu einer trans-und bei threo-Konfiguration zu ciner gauche-Konformation der freien Elektronenpaare. Contributions to the Chemistry of Phosphorus, 88'3') 1,2,3-Triphenyl-1,3-bis(trimethylsilyl)triphosphane The reaction of 1,3-dipotassium 1,2,3-triphenyltriphosphide, KJPPh),, with chlorotrimethylsilane yields the hitherto unknown title compound Me,Si(Ph)P-P(Ph)-P(Ph)SiMe, (l), which is remarkably stable against disproportionation reactions. In solution it forms the three diastereomers l a (eryt/rro/rryt/irc,), lb(erythro/threo), and l c (rllreo/th~~eo) in a ratio ofabout 8:3:1, between which a dynamic equilibrium exists due to pyramidal inversion at the P-atoms. The correlation between the 'P-NMR-spectroscopically observed spin systems and the diastereomers 1 ac results from the significant dependence of the ' J ,,,,-coupling constants on dihedral angles. The preferred trans arrangement of the bulky %Me,-and P(Ph)SiMe, groups at adjacent P-atoms leads to a trans-conformation of the lone electron pairs in the cvythro-and to a gauclze-conformation in the threo-configuration. Vor einigen Jahren konnte als erstes silyliertes Diphosphanderivat 1,2-Diphenyl-1,2-bis(trimethylsilyl)diphosphan, Me,Si(Ph)P-P(Ph)SiMe,, durch Trimethylsilylierung von 1,2-Dikaliuni-1,2-diphenyldiphosphid dargestelli werden"'. lnzwischen haben die davon ausgehenden Synthesen von 1,2-Diphenyldiphosphan, H(Ph)P-P(Ph)H '1, und von Triphenylcyclotriphosphan, [PPh], '), die allgemeine praparative Bedeutung der partiell silylierten kettenformigen Organylphosphane gezeigt. Im Rahmen unserer Untersuchungen iiber Phenylphosphane offenkettiger und cyclischer Struktur 4-') war das noch unbekannte 1,2,3-Triphenyl-1,3-bis(trimethylsilyl)triphosphan (1) von besonde

Zeitschrift für Naturforschung B, 1976

The weak resonances at + 22 and + 49 ppm appearing in the 31P NMR spectrum of melts or solutions ... more The weak resonances at + 22 and + 49 ppm appearing in the 31P NMR spectrum of melts or solutions of (PPh)5 that have been attributed previously in the literature to “dimeric” and “monomeric phenylphosphorus” are caused by (PPh)6 and (PPh)4, respectively. This was proved by comparison with the 31P NMR parameters of related compounds and by 31P NMR spectroscopic investigation of authentic samples of (PPh)6 and (PPh)4, the latter of which was prepared in high yield from (Me3Si)PhP–PPh–PPh(SiMe3) and PhPCl2. (PEt)4 and mixed-substituted phenyl-ethyl-cyclotetraphosphanes exhibit similar chemical shifts as (PPh)4, corresponding mixed-substituted cyclohexaphosphanes have similar chemical shifts as (PPh)6. Generally, cyclophosphanes establish an equilibrium between (PR)n-species of different ring-size. Probably, the ring-interconversion proceeds via a multi-center mechanism. No 31P NMR spectroscopic evidence for the existence of free PPh or P2Ph2 under the conditions described could be dete...

Chemischer Informationsdienst

Chemischer Informationsdienst

Zeitschrift f�r anorganische und allgemeine Chemie, 1977

Bei der Reaktion von (CH3)3Si(C6H5)PP(C6H5)Si(CH3)3 mit RPCl2 (R = C6H5, C2H5, CH3) werden die Cy... more Bei der Reaktion von (CH3)3Si(C6H5)PP(C6H5)Si(CH3)3 mit RPCl2 (R = C6H5, C2H5, CH3) werden die Cyclotriphosphane (PC6H5)31 bzw. (PC6H5)2(PC2H5) 3 bzw. (PC6H5)2(PCH3) 4 gebildet. Daneben entstehen die entsprechenden einheitlich- bzw. gemischtsubstituierten Cyclotetraphosphane, Cyclopentaphosphane und Cyclohexaphosphane. Der Anteil der Cyclotriphosphane im Reaktionsgemisch nimmt fortlaufend ab, wahrend derjenige der Cyclopentaphosphane ansteigt. Die Ursachen dieser Ringumlagerungen von Cyclophosphanen (PR)n werden diskutiert. Die Cyclotriphosphane 1, 3 und 4 sind im 31P-NMR-Spektrum durch chemische Verschiebungen im Bereich von +130 bis +160 ppm charakterisiert und zeigen damit eine starke Hochfeldverschiebung gegenuber offenkettigen Triphosphanen und Cyclophosphanen anderer Ringgrose. Die Substituenten R sind auf beiden Seiten der P3-Ringebene angeordnet, so das fur 3 zwei mogliche Diastereomere resultieren, die in dem statistisch zu erwartenden Populationsverhaltnis nebeneinander vorliegen. Die 31P-NMR-Parameter fur 1 und 3 werden mitgeteilt und diskutiert. Contributions to the Chemistry of Phosphorus. 67. About the Cyclotriphosphanes (PC6H5)3, (PC6H5)2(PC2H5), and (PC6H5)2(PCH3) The reaction of (CH3)3Si(C6H5)PP(C6H5)Si(CH3)3 with RPCl2 (R = C6H5, C2H5, CH3) yields the cyclotriphosphanes (PC6H5)31, (PC6H5)2(PC2H5) 3, and (PC6H5)2(PCH3) 4, respectively. Besides, the corresponding homo- and mixed-substituted cyclotetraphosphanes, cyclopentaphosphanes, and cyclohexaphosphanes are formed. The relative concentrations of the cyclotriphosphanes in the reaction mixtures decrease continuously, whereas those of the cyclopentaphosphanes increase. The reasons for these ring-interconversion reactions of the cyclophosphanes (PR)n are discussed. The cyclotriphosphanes 1, 3, and 4 are characterized by 31P chemical shifts between +130 and +160 ppm that are at considerable high field compared to open-chain triphosphanes and cyclophosphanes of different ring-size. The substituents R are situated on both sides of the P3-ring plane, thus giving rise to two diastereomers of 3 that are observed simultaneously in the statistically expected ratio. The 31P n.m.r. parameters of 1 and 3 are reported and discussed.

Chemischer Informationsdienst, 1980

1,2-Diphenyldiphosphan (1) wird - entgegen Literaturangaben - bei der Reaktion von KHPPh mit 1,2-... more 1,2-Diphenyldiphosphan (1) wird - entgegen Literaturangaben - bei der Reaktion von KHPPh mit 1,2-Dibromethan gebildet. Reines 1 ist durch Hydrolyse oder Alkoholyse von Me3Si(Ph)P - P(Ph)SiMe3 unter Lichtausschlus erhaltlich und bei − 30°C bestandig. Es disproportioniert bei Raumtemperatur in PhPH2, hohere Homologe der Reihe H2[PPh]n — insbesondere H2[PPh]3 - und cyclische Phenylphosphane [PPh]n — vor allem [PPh]5. Diese Umlagerungen werden durch Licht, Phosphide sowie starke Sauren und Basen beschleunigt. Mit K(Ph)PP(Ph)K, Me3Si(Ph)PP(Ph)SiMe3 oder P2Ph4 reagiert 1 zu den unsymmetrischen Diphosphanen K(Ph)PP(Ph)H, Me3Si(Ph)PP(Ph)H bzw. Ph2PP(Ph)H. Die NMR-, IR- und Raman-Spektren von 1 werden diskutiert. Contributions to the Chemistry of Phosphorus, 73: 1,2-Diphenyldiphosphane 1,2-Diphenyldiphosphane (1) is formed, contrary to results given in the literature, by the reaction of KHPPh with 1,2-dibromoethane. Pure 1 is obtained by hydrolysis or alcoholysis of Me3Si(Ph)P-P(Ph)SiMe3 in ...

1,2 - Diphenyl - 3,3 - dimethyl - diphosphirane (1,2- Diphenyl- 3,3- dimethyl-diphosphacyclopropa... more 1,2 - Diphenyl - 3,3 - dimethyl - diphosphirane (1,2- Diphenyl- 3,3- dimethyl-diphosphacyclopropane) (1) is formed by the reaction of K(C6H5)P–P(C6H5)K with 2,2-dichloropropane in n-pentane at —30 °C. It could be detected and identified by its 31P NMR singlet at —122 ppm, which lies in the high field region characteristic for phosphorus three-membered ring compounds, as well as by its mass spectrum. Besides, (PC6H5)5 and several cyclocarbaphosphanes of ring sizes five and six are formed. After the reaction of (CH3)3Si(C6H5)P–P(C6H5)Si(CH3)3 with methylene iodide a weak 31P NMR signal at —147 ppm could be observed, which probably corresponds to the 1,2-diphenyl-diphosphirane.

Zeitschrift für Naturforschung B

1,2 - Diphenyl - 3,3 - dimethyl - diphosphirane (1,2- Diphenyl- 3,3- dimethyl-diphosphacyclopropa... more 1,2 - Diphenyl - 3,3 - dimethyl - diphosphirane (1,2- Diphenyl- 3,3- dimethyl-diphosphacyclopropane) (1) is formed by the reaction of K(C6H5)P–P(C6H5)K with 2,2-dichloropropane in n-pentane at —30 °C. It could be detected and identified by its 31P NMR singlet at —122 ppm, which lies in the high field region characteristic for phosphorus three-membered ring compounds, as well as by its mass spectrum. Besides, (PC6H5)5 and several cyclocarbaphosphanes of ring sizes five and six are formed. After the reaction of (CH3)3Si(C6H5)P–P(C6H5)Si(CH3)3 with methylene iodide a weak 31P NMR signal at —147 ppm could be observed, which probably corresponds to the 1,2-diphenyl-diphosphirane.

Chemischer Informationsdienst