摘要:

AbstractThis paper is devoted to the steric aspects of the efficiency and selectivity of extractants in the process of extraction of metal cations from acidic aqueous solution into a nonpolar phase. The extraction of uranium, plutonium, americium, and europium by tertiary carbamoylmethyl phosphine oxides and polydiphenylphosphinylmethyl benzenes have been studied. The separation factors of uranium and plutonium from americium are measured. Tertiary carbamoylmethyl phosphine oxides and diphenylphosphinylmethyl benzenes of the ortho type are characterized by unusually high separation factors. The diphenylphosphinylmethyl derivatives of benzene of the meta type do not possess a high selectivity in the process of separation of uranium and plutonium from americium, but are more efficient in extraction of americium.

ISSN:1042-7163    

DOI:10.1002/hc.520020102

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe reaction of (t‐BuGaCl2)2with Ar′P(H)Li (AR′ = 2,4,6‐t‐Bu3C6H2) affords the chloride‐bridged dimer [t‐BuGa(Cl)P(H)Ar′]2(1). The structure of1has been established by X‐ray crystallography. Compound1, C44H78Cl2Ga2P2, crystallizes in the monoclinic space group P21/n withZ= 2, a = 10.468(1), b = 14.967(1), c = 16.182(2) Å, and Å = 94.48(1)β. The reaction of1wit

ISSN:1042-7163    

DOI:10.1002/hc.520020103

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe synthesis of 2,2′‐bis(bis(dimethylamino)‐phosphino)‐3,3′5,5′‐tetra‐tert‐butylbiphennyl (5) is described. It was extensively studied by1H,13C, and31P NMR spectroscopy. Furthermore, the X‐ray analysis of5is reported. Crystals of5are tetragonal, space group P¯421c,a = b =24.770 (3) Å,c= 12.658 (4) Å, Z = 8. The surprising reaction of5with proton acids leading to the formation of various phosphorus containing five‐ and six‐membered ring compounds is discussed. On reaction of one of the six‐membered ring compounds (9) with magnesium in THF, a λ3, λ5‐diphosp

ISSN:1042-7163    

DOI:10.1002/hc.520020104

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThermolysis of [bis(diisopropylamino)phosphanyl](trimethylsilyl)diazomethane1affords the corresponding carbene2, which is stable enough to be spectroscopically characterized. This species possesses a phosphorus–carbon multiple‐bond character as shown by the 2 + 3 and 2 + 2 cycloaddition reactions observed with trimethylsilyl azide or N2O and ethyl cyanoformate, respectively. On the other hand,2undergoes all the classical reactions of a carbene: cyclopropanation reaction with electron‐poor alkenes, carbon–hydrogen bond insertion, and carbene–carbene coupling with isonitriles. Compound2reacts with trimethylsilyl triflate affording a stable methylenephosphonium salt15. Treatment of the lithium salt of the [bis(diisopropylamino)thiophosphoranyl]diazomethane18with the bis(diisopropylamino)phosphanyl chloride leads to a stable nitrilimine3. Thermolysis of3affords the isomeric diazo derivative20, while photolysis gives rise to thiophophoranylnitrile21and cyclodiphosphazene23. Regioselective 2 + 3 cycloadditions are observed with electron‐poor dipolarophiles. Addition of trimethylsilyl triflate to3leads to a stable electrophilic ni

ISSN:1042-7163    

DOI:10.1002/hc.520020105

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractMolecular mechanics calculations, using the AMBER program (version 3.0), are presented on the radiogenic electron‐capture radical formation in the crystalline chiral organophosphorus compounds (2R,4S,5R) and (2S,4S,5R) 2‐chloro‐3,4‐dimethyl‐5‐phenylphospholidine 2‐sulfide (respectively1and2). Geometry optimization of the corresponding radical anion structures and their respective crystal surroundings reveals an increase of the Van der Waals interactions, which is significantly larger in compound2than in1. This is in good agreement with previous single‐crystal ESR experiments and molecular interactions calculations without geometry o

ISSN:1042-7163    

DOI:10.1002/hc.520020106

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractA general synthesis of various polyazaphosphorus macrocycles involving [1 + 1], [2 + 2], or [3 + 3] cyclocondensations is reviewed, as well as the attempted synthesis of cryptands. Selective reduction (imino functions) methylation (PS groups), silylation (PO groups) are reported. Preparations of some macrocycle complexes are descri

ISSN:1042-7163    

DOI:10.1002/hc.520020107

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractA stereoselective synthesis of α,β‐unsaturated phosphonates based on the reaction of S‐(β‐oxoalkyl)‐dithiophosphates and Se‐(β‐oxoalkyl)selenophosphates with sodium dialkyl phosphit

ISSN:1042-7163    

DOI:10.1002/hc.520020108

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractMany observations prove that a number of silylation reactions of a trialkylsilyl halide‐uncharged base system occur with the transient formation of a 1:1 tetrahedral silicon ionic complex of the silyl halide with the base. Some catalytic processes of phosphorylation of protonic substrates with tricoordinate phosphorus halides in mixture with an uncharged base show similar features to these silylation reactions, implying that a similar mechanism may operate. It was demonstrated that Ph2PCl phosphorylates t‐BuOH faster under catalysis with 4‐N,N‐dimethylamino pyridine orN‐methylimidazole than in the presence of Et3N by a factor of 400 and 33, respectively. The catalytic phosphorylation process exhibits a very low activation energy and a high negative value of entropy of activation. The interaction of the uncharged bases with model tricoordinate phosphorus halides was demonstrated to lead to the formation of ionic 1:1 complexes without changing the coordination number of phosphorus, in full analogy to the silyl halide complex formation. Finally, the interaction of phosphorous tris(dimethylamide) with a silyl iodide and a phosphorous iodide results in both cases in the formation of the ionic 1:1 complex, which also leads to analogous reactions of exchange of the amide group with iodide. These close similarities imply that some phosphorylation reactions with tricoordinate phosphorus halides catalyzed with uncharged bases occur via a tricoordinate phosphorus cation int

ISSN:1042-7163    

DOI:10.1002/hc.520020109

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe reaction of 10‐P‐5 hydridophosphorane6with KH provides the 10‐P‐4 potassium phosphoranide anion7a. Anion7areacts with CpFe(CO)2I and BrAu(PEt3) to replace the halide with the phosphoranide as a monodentate ligand forming8and9. The X‐ray structure of8shows that the equatorial—Fe(CO)2Cp ligand of8makes the apical PO bonds (1.824 Å) longer than the PO bonds (1.80 Å) of the phosphoranide oxide anion10. The PO bonds (1.75 Å) of6, with an equatorial proton ligand, are still shorter. This provides evidence that the—Fe(CO)2Cp ligand is not only a sigma‐acceptor Lewis acid ligand, but also a pi‐donor that transfers electrons into the OPO three‐center bond's anti‐bonding orbital to increase its P—O bond lengths. It is a better pi‐donor than th

ISSN:1042-7163    

DOI:10.1002/hc.520020110

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractTheN,N,N′‐trimethylethylenediaminetetrafluorophosphate,4, was formed in the unusual reaction ofN,N,N′‐trimethyl‐N′‐trimethylsilylethylenediamine,1, with the NP‐bonded tetrafluorophosphoranes, dimethylaminotetrafluorophosphorane,2, or morpholinotetrafluorophosphorane,3. There was no evidence for the cleavage of a PF bond in the tetrafluorophosphoranes (with formation of Me3SiF); instead, the SiN compounds, R2NSiMe3(R2= Me2or O(CH2CH2)2) were formed. The19F and31P NMR spectra of4at room temperature indicated dynamic behavior. The X‐ray crystal structure analysis of4revealed the presence of a five‐membered ring, formally as a result of intramolecular donor–acceptor interaction (PN = 196.5 pm) between the nitrogen atom o

ISSN:1042-7163    

DOI:10.1002/hc.520020111

出版商:VCH Publishers, Inc.    

年代:1991

数据来源: WILEY