CRYSTAL STRUCTURE OF THE NOVEL COMPOUND (1α, 3bT, 5α)-1,3-DIPHENYL-5-HYDRIDO-5-ISOPROPOXY-1λ6, 3λ6,2,4,6,5λ5-DITHIATRIAZAPHOSPHORINE-1,3-DIOXIDE. A COMPARISON WITH RELATED STRUCTURES

Abstract

The title compound (1α, 3β, 5α)-(NSOPh)₂NP(H)O-i-Pr crystallizes in the spacegroup P2₁/n with cell dimensions: a = 12. 150(2), b = 8.911(1), c = 17.614(3) Å, β = 107.52(1)^o; Z = 4. The structure was solved by direct methods and refined by least-squares techniques to an R value of 0.048 for 2420 independent reflections (collected at room temperature) with I > 2.5 σ(I). The unit cell contains dimeric units which are formed by unprecedented P[sbnd]H…O[dbnd]S bridges. The conformation of the inorganic ring skeleton can be described as a boat; phosphorus and sulfur atoms show a distorted tetrahedral geometry. The S[sbnd]N bond lengths differ slightly, ranging from 1.547(3) to 1.588(2) Å. The exocyclic bond lengths are P[sbnd]H = 1.34(2), P[sbnd]O = 1.553(2), S[sbnd]O = 1.439(2) (mean value), and S[sbnd]C = 1.767(4) (mean value) Å. From a comparison with analogous structures the degree of asymmetry (ΔI = {[P[sbnd]N]-[S[sbnd]N]}Å) in the SNP unit is related to the difference in electronegativity between the sulfur and phosphorus centres.     

CARBODIPHOSPHAN (2.4.6-tBu3C6H2[sbnd]P[dbnd]2)C: REAKTION MIT ELEKTROPHILEN

Abstract

The reaction of Ar[sbnd]P[dbnd]C[dbnd]P[sbnd]Ar (Ar=2.4.6-^tBu₃C₆H₂) with electrophiles (H⁺, S₈) proceeds at the phosphorus atom with subsequent cyclisation of an o-^tbutyl group.     

METALLAPHOSPHENES AND DIPHOSPHENES

Abstract

Transient metallaphosphenes (rbnd2;M[dbnd]P[sbnd]) have been obtained by exchange reactions between disilylphosphines and organometaldihalides (M = Ge, Sn), or by thermolysis of 2-metallaphosphetanes (M = Si, Ge). They are characterized by trapping reactions with strained heterocycles. The first stable germaphosphene 12 has been synthesized by dehydrohalogenation from the parent halogermylphosphine and isolated in form of orange crystals. It is very reactive toward compounds with active hydrogen.

Transient diphosphenes ([sbnd]P[dbnd]P[sbnd]) have been prepared by the same type of exchange reactions between disilylphosphines and dichlorophosphines and characterized by trapping reactions on dienes. The second stable diphosphene 18 has been obtained by addition of t-BuLi on trisyldichlorophosphine. Its structure has been determined by X-ray diffraction and some aspects of its reactivity are described. The reaction of bisyltrichlorogermylphosphine with DBU affords the new stable and potentially reactive diphosphene 30.     

CRYSTAL AND MOLECULAR STRUCTURE OF BIS(TRIPHENYLBENZYLPHOSPHONIUM) TETRABROMOCADMATE

Abstract

The molecular and crystal structure of bis(triphenylbenzylphosphonium)tetrabromocadmate has been determined by x-ray diffractometer data. Crystals are triclinic, space-group Pl with two formula units in a unit-cell of dimensions a = 12.506(6), b = 10.471(5), c = 18.396(13) Å, α = 93.07(4)°, β = 105.75(5)°, γ = 92.58(4)°. The structure was solved by direct and Fourier methods and refined by least-squares techniques to R = 0.061 for 3723 independent observed reflections. The structure consists of tetrabromocadmate (II) anions and triphenylbenzylphosphonium cations, both with a quasi-perfect tetrahedral symmetry around the cadmium and phosphorus atoms. The most significant average bond distances are: Cd-Br, 2.588(2) Å, P[sbnd]C (Phen), 1.794(5) Å and P[sbnd]CH₂, 1.806(6) Å. The P[sbnd]C (Phen) bonds are in slightly distorted staggered conformation (gauche-, gauche +, and trans) in respect of the C (Phen)-CH₂ bonds of the benzyl residues. The interatomic distances between the ions correspond to the usual Van der Waals distances.     

UNUSUAL DIRECTION OF THE ARBUZOV REACTION OF DIALKOXYMETHYLPHOSPHONITES AND THEIR ANALOGUES

Abstract

The alkylation and acylation reactions of dialkoxymethylphosphonites and their analogues have been studied. The Arbuzov rearrangement of these compounds was accompanied by the P[sbnd]C bond cleavage with retention of three-coordinate phosphorus atom.     

OBERFLÄCHEN-REAKTIONEN 151,2 Heterogen Dechlorierungen von Phosphorchloriden (X)PCI3 und R[sbnd]PCI2 an [Ag], [Mg], [Cux/TiO2] und [MgCI2[sbnd]MgO/SiO2] sowie spektroskopische Evidenz für das Entstehen von Diphospha-dicyan P[tbnd]C[sbnd]C[tbnd]P aus CI2P[sbnd][tbnd][sbnd]PCI2

Abstract

Stimulated by the successful generation of unsaturated molecules with low-coordinated phosphorus centers by heterogeneous surface dechlorination, CI₂,P[sbnd]C[tbnd]C[sbnd]PCI², is synthesized and characterized by PE and mass spectra. In addition, [Mg] curls, [Ag] wool and catalysts [Cu_x/TiO₂] or [MgCI₂,[sbnd]MgO/SiO₂] are tested as potential dechlorinating agents for phosphorus halides like OPCI₃, SPCI₃, H₃C[sbnd]PCI₂, H₅C₂-PCI₂, (H₃C)₃C[sbnd]PCI₂, or H₅C₆-PCI₂, in a gasflow reactor under reduced pressure and yield, inter aha, the following representative results: due to the thermodynamically favored formation of [MgCl₂], [MgO] or [MgS] at the Mg surface, P₄ is the only gaseous product identified from reactions of OPCI₃, and SPCI₃, with [Mg] metal at higher temperatures. On the contrary, passing H₃C-PCI₂, at 600K over [Mg] yields a reaction mixture containing P(CH₃)₃,(H₃C)₂P[sbnd]P(CH₃)₂, (H₃C[sbnd]P), and CH₄, which suggests an intermediate formation of surface phosphinidenes [H₃C[sbnd]P →Mg]. Analogously, the pentamer (H₃C[sbnd]H₂C[sbnd]P)₅ can be isolated from ethyldichlorophosphane. Reaction of the evaporated diphospha-cyanogen precursor CI₂P[sbnd]C[tbnd]C[sbnd]PCI₂ with the catalyst [10% MgCI₂,/MgO/SiO₂], produces predominantly PCI₃, and P₄, but PE and mass spectra provide evidence that also minor amounts of the hitherto unknown molecule P[tbnd]C[sbnd]C[tbnd]P are formed.     

THE PREPARATION AND CHARACTERIZATION OF Cd(XCN)4M TYPE COMPOUNDS

Abstract

A series of compounds of the type Cd(XCN)₄M (X=S and Se; M=Mn, Fe, Co and Zn) have been prepared and characterized. These compounds crystallize in the tetragonal system: space group I4[sbnd]S₄ ². The bidentate thiocynate and selenocyanate ligands coordinate to the “hard” M(II) ions through the nitrogen atom and the “soft” Cd(II) ion through the sulfur or selenium atom. The Cd[sbnd]Se bond in Cd(XCN)₄ M is slightly stronger than the Cd[sbnd]S bond while the M[sbnd]NCSe bond is slightly weaker than the M[sbnd]NCS bond. The M(II) ions tetrahedrally coordinated by the nitrogen end of XCN^? are in the high spin state. The [sbnd]NCS and [sbnd]NCSe ligands are located at about the same place in the spectrochemical series.     

METAL ISOTOPE EFFECT ON METAL-LIGAND VIBRATIONS: V. CIS AND TRANS Ni(II) PHOSPHINE-HALIDE COMPLEXES

Abstract

Infrared spectra (4000–200 cm^?1) have been reported for Ni(DPE)X₂ where X is Cl, Br and I and DPE is 1,2-bis(diphenylphosphino)ethane. The Ni[sbnd]X and Ni[sbnd]P stretching bands have been assigned based on the observed isotopic shifts due to the ⁵⁸Ni-⁶²Ni substitution. The Ni[sbnd]X stretching frequencies are always lower and the Ni[sbnd]P stretching frequencies are always higher in the cis-complexes such as Ni(DPE)X₂ than in the corresponding trans-complexes such as Ni(PEt₃)₂X₂. These differences between cis and trans configurations have been attributed to the strong trans-effect of phosphine ligands.     

PHOSPHORYL TO CARBONYL MIGRATION OF AMINO GROUPS IN MIXED ANHYDRIDES. REACTIVITY AND CRYSTAL STRUCTURE OF N-METHYL-2-BENZOYLOXY-2-OXO-1,3,2-OXAZAPHOSPHORINANE

Abstract

Cyclic mixed anhydride, N-methyl-2-benzoyloxy-2-oxo-1,3,2-oxazaphosphorinane (1a) has been synthesised and the rate of its fragmentation involving nitrogen migration from phosphorus to carbonyl carbon has been measured. (1a) was found to be ca. 60 times less reactive than the non-cyclic, O-methyl-N,N-dimethyl analogue. The crystal and molecular structure of (1a) has been determined using x-ray diffraction. Pna2₁, a=22.229(6), b=7.597(2), c=7.210(2) Å; V=1217.6(6) ų. Final R=3.08% for 1037 reflections with I(rel) > 2[sgrave]I(rel) and 157 parameters. The observed conformation of the molecule of (1a) is very different from that required for the fragmentation to occur; in order to achieve the geometry postulated for the transition state significant rotations about the P[sbnd]O and O[sbnd]C bonds would be necessary and steric hindrance by the 4,6-axial hydrogens would be expected.     

SPIROPHOSPHORANES – STRUCTURE REACTIVITY

Abstract

The first part of this article will deal with the reactions of spirophosphoranes with a P[sbnd]H bond. These compounds contain two five-membered rings and have four oxygen atoms, or three oxygen atoms and one nitrogen atom, or two oxygen and two nitrogen atoms directly bonded to the phosphorus atom, which in all cases bears an hydrogen atom (Scheme 1). The most remarkable property of these compounds is undoubtedly their ability to give rise to a tautomeric equilibrium between the tri- and penta-coordinated structures P_III→P_V.     

Density studies in terephthalylidene-bis-p-n-alkylanilines

Abstract

The temperature dependence of density in terephthalylidene-bis-p-n-alkylanilines (TBAA5 and 6) is studied to investigate the phase transitions, associated volume jumps, order of the transitions, estimated pressure dependence of transition temperatures, and pretransitional effects. The compounds exhibit nematic, smectic A, smectic C, smectic F, smectic G and smectic H phases with higher clearing temperatures. The smectic A to smectic C transition, which is a fluctuation induced first order transition in TBAA5, is found to be a second order transition in TBAA5 and 6. The results are discussed in the light of other experimental reports. The estimated pressure dependence of transition temperatures along with the reported experimental P[sbnd]T data are discussed. The N[sbnd]S_A transition is first order in TBAA5 and 6. The studies across other transitions are also discussed.     

REACTIONS OF A PHOSPHORANIMINE ANION WITH SOME ORGANIC ELECTROPHILES

Abstract

The reactions of a variety of electrophiles with the N-silyl-P-trifluoroethoxyphosphoranimine anion Me₃Sin°P(Me)(OCH₂CF₃)CH^? ₂ (1a), prepared by the deprotonation of the dimethyl precursor Me₃SiN[dbnd]P(OCH₂CF₃)Me₂ (1) with n-BuLi in Et₂O at-78°C, were studied. Thus, treatment of 1a with alkyl halides, ethyl chloroformate, or bromine afforded the new N-silylphosphoranimine derivatives Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂R [2: R = Me, 3: R = CH₂Ph, 4: R = CH[sbnd]CH₂, 5: R = C(O)OEt, and 6: R = Br]. In another series, when 1a was allowed to react with various carbonyl compounds, 1,2-addition of the anion to the carbonyl group was observed. Quenching with Me₃SiCl gave the O-silylated products Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂°C(OSiMe₃)R¹R² [7: R ¹ = R ² = Me; 8: R ¹ = Me, R ² = Ph; 9: R¹ = Me, R ² = CH[sbnd]CH₂; and 10: R ¹ = H, R ² = Ph]. Compounds 2–10 were obtained as distillable, thermally stable liquids and were characterized by NMR spectroscopy (¹H, ¹³C, and ³¹P) and elemental analysis.     

MOLEKÜLSTRUKTUR EINES STABILEN PENTAOXY-SPIROPHOSPHORANS MIT PHOSPOR ALS BRÜCKENKOPFATOM ZWISCHEN EINEM SECHSGLIEDRIGEN UND EINEM FÜNFGLIEDRIGEN RING

Abstract

The crystal and molecular structure of the trigonal-bipyramidal pentaoxy-spirophosphorane 1 reveals the smaller influence on the stereochemistry at phosphorus of the six-membered compared with five-membered rings. The large difference between the two axial P[sbnd]O bonds (161.6 and 171.0 pm) and between the three equatorial P[sbnd]O bonds (range 157.7–163.6 pm) is ascribed to the influence of the CF₃-groups on the electronegativity of the oxygen atoms.     

Liquid crystals of some new tolane derivatives containing a 1,2-ethylene linkage

Abstract

Three types of nematogenic compound, 4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-alkyltolanes, 2-fluoro-4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-alkyltolanes and 4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-halogenotolanes, have been synthesized and their transition temperatures and enthalpies determined. Their bulk viscosity and birefringence have been estimated from those of mixtures with other liquid-crystalline compounds. These compounds have been found to be excellent materials for twisted nematic displays, because of their wide nematic temperature range, high birefringence (Δn = 0·26), and low viscosity (η = 21 cP at 20°C). Several related compounds having other central linkages, namely -CH₂O-, a single bond or -COO-, in place of the 1,2-ethylene group, have also been studied.     

SYNTHESIS,REACTIVITY AND CONFORMATION OF 10,11-DIHYDRODIBENZO-[b,f]PHOSPHEPIN AND DIBENZO[b,f]PHOSPHEPIN DERIVATIVES. PHOSPHORUS ANALOGUES OF IMINOBIBENZYL ANTIDEPRESSANTS

Abstract

Derivatives of the novel dibenzo[b,f]phosphepin system are prepared from 10,11-dihydro-5-phenyl-5H-bibenzo[b,f]phosphepin 5-oxide (2). New members in the 10,11-dihydro-5H-dibenzo[b,f]phosphepin series, including phosphorus analogues (7, 10) of the andidepressant drug imipramine (30), are also reported. Products of nucleophilic substitution at tetrahedral phosphorus in 2 appear to be determined by the relative apicophilicity of the nucleophile. Conformational analysis based on ¹H NMR data suggests folded (“butterfly”) conformation for the tricyclic compounds. The twisted boat conformation of the central ring in the 10,11-dihydro compounds bears a pseudo-equatorial P[dbnd]O oxygen or a P[dbnd]S sulfur, in solution. Symmetric AA‘BB’ spin systems are found in 4,5 and 7, and their solution conformations appear to be similar to those of analogous 10,11-dihydrodibenzo[b,f]azepine derivatives. The interaction of some compounds with NMR shift reagents and their mass spectral fragmentations are discussed.     

CYCLIC ORGANOPHOSPHORUS COMPOUNDS. PART XVI1. MASS SPECTROMETRIC FRAGMENTATION OF SOME 5,5-DIMETHYL-1,3,2-DIOXAPHOSPHORINAN 2-OXIDES AND 2-SULPHIDES

Abstract

The mass spectra of seventeen 5,5-dimethyl-1,3,2-dioxaphosphorinan 2-oxides and nineteen 5,5-dimethyl-1,3,2-dioxa-phosphorinan 2-sulphides, mostly with amino substituents on phosphorus, have been determined. In some cases, interpretation of the spectra was aided by accurate mass measurements and by the examination of deuterated compounds. For the 2-sulphides, sulphur is lost either as such or as the thiol radical, both processes often being of weak intensity, and the thiol hydrogen appears to be derivable from either a ring methylene group or a C-5 methyl group. Loss of S or HS occurs more strongly for the phosphoramidothionates which, together with the phosphoramidates, also fragment to an important extent in the amido substituent with retention of the dioxaphosphorinan ring; P[sbnd]N bond cleavage is also observed. For the 2-thiones, the ions at m/e 165 (14; R[dbnd]H) and 133 (15; R[dbnd]H) are characteristic.     

ORGANOGERMANIUM(IV) O,O,ALKYLENEDI-THIOPHOSPHATES

Abstract

Tri- and di-organogermanium(IV) O,O-alkylenedithiophosphates R_4-n ,Ge(S₂PO₂G)_n (where R = Ph. Bu, Et. G =—C(CH₃)₂C(CH₃)₂[sbnd], [sbnd], CH₂C(CH₃)₂CH₂[sbnd], [sbnd]CH—CH₃CH₂C(CH₃)₂[sbnd], n= 1, 2) were synthesized by treatment of organogermanium(IV) chlorides with ammonium O,O-alkylenedithiophosphates in benzene. These are volatile, liquids except the phenyl ones which are solids. All of these are miscible in organic solvents and monomeric in refluxing benzene. Like dialkyldithiophosphate derivatives of organogermanium these cyclic ones also appear to be tetrahedral with the ligands behaving as unidentate ones.     

INTRODUCTION DE SYSTÈMES CAGE DANS LES MOLÉCULES D'INTÉRĚT BIOLOGIQUE. 2. ALKYLATION DES ESTERS SULFAMIQUES AU MOYEN D'UN DÉRIVÉ DE L'ADAMANTANE

Abstract

Sulfamic esters of the general type R[sbnd]O[sbnd]SO₂[sbnd]NH₂ were alkylated under solid-liquid, liquid-liquid phase transfer catalysis conditions and by noncatalytic procedure, in homogeneous medium, in the presence of an equimolar amount of triethylamine, by means of a 1-adamantyl bromomethyl ketone. According to the procedure and the nature of R, these reactions yield the N-monoalkyl, N-dialkyl derivatives or a cleavage of the O[sbnd]SO₂ bond with formation of the O-alkylation products.

Nous decrivons l'alkylation des esters sulfamiques de formule générale R[sbnd]O[sbnd]SO₂[sbnd]NH₂ au moyen de l'adamantyl-1 bromométhyl-cétone, en catalyse par transfert de phase solide-liquide, liquide-liquide et dans les conditions non-catalytiques, en phase homogène et en présence d'une quantité équimoléculaire de triéthylamine. Selon la méthode utilisée et la nature du radical R. on aboutit à des dérivés N-monoalkylés, N-dialkylés ou à la scission de la liaison O[sbnd]SO₂ avec formation de produits de O-alkylation.     

STUDIES ON ORGANOPHOSPHORUS COMPOUNDS XXX. MASS SPECTROSCOPIC INVESTIGATION OF 2-ALKYL-2-OXO-1,3,2-DIOXA-PHOSPHORINANE AND-PHOSPHEPANE

Abstract

The mass spectra of 2-alkyl-2-oxo-1,3,2-dioxa-phosphorinane and-phosphepane showed that the ring opening was in competition with the cleavage of the P[sbnd]C bond. According to the fragmentation pathway, which was dependent on the structure of exocyclic substituents on phosphorus, the 2-alkyl-2-oxo-1,3,2-di-oxa-phosphorinanes can be classified in two categories. The main process in category A was the ring opening and/or C[sbnd]C bond cleavage. While in category B the cleavage of P[sbnd]C bond was predominant. However, for 2-alkyl-2-oxo-1,3,2-dioxa-phosphepane. no matter how the structure of 2-alkyl group was, the ring opening was a dominant process.