Acyl- und Alkylidenphosphane. XXIV. (N,N-Dimethylthiocarbamoyl)trimethylsilylphosphane und 1,2-Di(tert-butyl)-3-dimethylamino-1-thio-4-trimethylsilylsulfano-1λ5,2λ3-diphosphet-3-en

Acyl- and Alkylidenephosphines. XXIV. (N,N-Dimethylthiocarbamoyl)trimethylsilyl-phosphines and 1.2-Di(tert-butyl)-3-dimethylamino-1-thio-4-trimethylsilylsulfano-1λ⁵, 2λ³-diphosphet-3-ene In contrast to bis(trimethylsilyl)phosphines R? P[? Si(CH₃)₃]₂ 1 {R ? H₃C a ; (H₃C)₃C b ; H₅H₆ c ; H₁₁C₉ d ; (H₃C)₃Si e }, the more nucleophilic lithium trimethylsilylphosphides 4 react with N,N-dimethylthiocarbamoyl chloride already at ?78°C to give (N,N-dimethylthiocarbamoyl)trimethylsilylphosphines 2 . Working up the reaction, a dismutation of the mesityl derivative 2d is observed, whereas the tert-butyl compound 2b dissolved in toluene, eliminates dimethyl(trimethylsilyl)amine to form 1,2-di(tert-butyl)-3-dimethylamino-1-thio-4-trimethylsilyl-sulfano- 1λ⁵, 2λ³-diphosphet-3-ene 6b , nearly quantitatively within several days at +20°C.     

Molekül- und Kristallstruktur von 9λ4-Thia-2,4,6,8,10,11-hexaza-1λ5,3λ5,5λ5,7λ5-tetraphosphabicylo[5.3.1]undeca-1,3,5,7(11),8,9-hexaen,einem schwefeldiimidoüberbrückten Cyclotetraphosphazen

Molecular and Crystal Structure of 9λ⁴-Thia-2,4,6,8,10,11-hexaaza-1λ⁵,3λ⁵,5λ⁵,7λ⁵-tetraphosphabicylo[5.3.1]undeca-1,3,5,7(11),8,9-hexaene, Cyclotetraphosphazene Bridged by a Sulfur Diimide Group We have carried out an X-ray structure analysis of the title compound ( 1 ). 1 crystallizes in the monoclinic space group P2₁/b with a = 9.436(4), b = 20.102(7), c = 11.622(5) Å, γ = 103.52(8)°, Z = 8. There are two molecules in the asymmetric unit, which in approximation can be transformed one into the other by additional symmetry elements of a substructure of a space group B2/b. The S = N bond lengths are 1.53 Å. The P? N bonds connecting the SN₂ system are 1.666 Å long. They are significantly longer than the P? N multible bonds in the P₄N₄ ring within a range of 1.517 to 1.565 Å. The sulfur diimide unit and its substituents are coplanar causing a half-boat conformation of the heterocyclic six membered ring. The cyclotetraphosphazene ring shows a flattened crown-saddle conformation, the phosphorous atoms arranged nearly at the corners of a square. Influenced by crystal packing there exist small deviations from the molecular mirror plane and also differences in conformation between the two molecules of the asymmetric unit.     

1λ6,2,4-Thiadiazetidine und 1,2λ6,3-Oxathiazetidine

1λ⁶,2,4-Thiadiazetidines and 1,2λ⁶,3-Oxathiazetidines From the reaction of the sulfur triimides (RN?)₃S ( 2a R?(CH₃)₃C, 2b R?(CH₃)₃Si) with pentafluoroazapropene ( 11 ) the appropriate 1λ⁶,2,4 thiadiazetidines ( 13a, 13b ) are formed, while from ClSO₂N?CCl₂ ( 14 ) and 2a (CH₃)₃C? N?C?N? SO₂Cl ( 17 ) is isolated. 2b and hexafluoroacetone ( 18 ) give the rather unstable 1,2λ⁶,3-oxathiazetidine ( 20 ).     

Element-Element-Bindungen. I. Synthese und Struktur des Tetra(tert-butyl)tetrarsetans und des Tetra(tert-butyl)tetrastibetans

Element-Element Bonds. I. Syntheses and Structure of Tetra(tert-butyl)tetrarsetane and of Tetra(tert-butyl)tetrastibetane Dilithium (tert-butyl)arsenide reacts with (tert-butyl)dichloroarsine to give tetra-(tert-butyl)tetrarsetane 1 ; homologous tetra(tert-butyl)tetrastibetane 2 is formed by reduction of (tert-butyl)dichlorostibane with magnesium. The isotypic compounds 1/2 crystallize in the monoclinic space group P2₁/c with Z = 4. The dimensions of the unit cells determined at ?45 ± 5°C are: a = 957.4(8)/1 000.2(3); b = 1 399.1(14)/1 423.9(4); c = 1 697.4(9)/1 749.8(7) pm; β = 96.02(6)/96.77(3)°. As shown by low temperature X-ray structure determinations (3 531/3 232 symmetry independent reflections; R_g = 4.0/4.6%) the four membered rings E₄ (E = As or Sb) are folded; in all-trans configuration the bulky organic substituents occupy pseudo-equatorial positions. Characteristic averaged bond distances and angles are: E? E 244/282; E? C 202/221 pm; ? E? E? E 86/85° ? E? E? C 101/99°. The dihedral angels of the bisphenoides built up by the atoms of the rings are found to be 139/133°.     

1,4-Dihydro-1λ5,4λ5-[1,4]diphosphinine und ein 1,4-Dihydro-1λ3,4λ3-[1,4]diphosphinin

1,4-Dihydro-1λ⁵,4λ⁵-[1,4]diphosphinines and a 1,4-Dihydro-1λ³,4λ³-[1,4]diphosphinine Reaction of thio- or dithiocarbonic acids with ethinyl amino phosphanes leads to 1,4-dihydro-1λ⁵,4λ⁵-[1,4]diphosphinine-1,4-disulfides. By this route compounds 4, 7 , and 8 have been prepared. Desulfurization of 4 with tri-n-butylphosphane results in 1,2,4,5-tetraphenyl-1,4-dihydro-1λ³,4λ³-[1,4]-diphosphinine 5 , which can be oxidized with tert-butyl-peroxide to the corresponding dioxide, 6 . From the reaction mixture of phenyl-phenylethinyl diethylamino phosphane and thioacetamide compound 4 and the unsymmetrical 1,4-dihydro-1λ⁵,4λ⁵-[1,4]diphosphinine 9 were isolated. Properties, nmr, ir and mass spectra of all new products are reported. A mechanism for the formation of 9 is suggested. The results of the X-ray structure determination of 8 and 9 are described.     

Cyclotri(λ3-phosphazane) (XPNMe)3: Darstellung,NMR-Spektren und Struktur

Ausgehend vom trihalogensubstituierten Cyclotri(λ³-phosphazan) 1 lassen sich die Derivate 2—12 in glatter Reaktion darstellen. Die sterische Belastbarkeit des Sechsring-systems hat mit X = NEt₂ in 11 ihre Grenze erreicht, für X = N? iPr₂ tritt nur noch Monosubstitution zu 13 ein, die aber eine Weitersubstitution mit sterisch weniger anspruchsvollen Resten, z. B. auch zu den Bicyclen 14—16 nicht ausschließt. Die NMR-spektroskopischen Daten legen eine Sesselkonformation der Cyclophosphazanringe nahe, wobei die diequatorial-axiale bzw. diaxial-equatoriale Konfiguration der Phosphoratome ( c, d ) als thermodynamisch günstigere Alternative zu a oder b verwirklicht ist. Es wird erstmals über eine Ringkontraktion vom Sechs- zum Vierring in der Reihe der Cyclo(λ³-phosphazane) berichtet. Cyclotri(λ³-phosphazanes) (XPNMe)₃: Preparation, NMR-Data, and Structure Cyclotri(λ³-phosphazanes) 2–12 are easily prepared from the trihalogeno substituted 1 . For steric reasons there is only a monosubstitution with X = N? iPr₂ to 13 , which nevertheless may be further substituted by sterically less demanding substituents to give e.g. the bicyclic compounds 14—16 . From NMR spectroscopic data a chair conformation of the six membered ring seems probable with the substituents at phosphorus being located either diequatorially axially ( c ) or vice versa ( d ) rather than a or b . A thermal ring contraction from a six to a four membered ring in the series of cyclo(λ³-phosphazanes) is reported for the first time.     

Alkylidinphosphane und -arsane. I [P ≡ C?S]−[Li(dme)3]+ – Synthese und Struktur

Alkylidynephosphanes and -arsanes. I [P ≡ C? S]^?[Li(dme)₃]⁺ – Synthesis and Structure O,O′-Diethyl thiocarbonate and bis(tetrahydrofuran)-lithium bis(trimethylsilyl)phosphanide dissolved in 1,2-dimethoxyethane, react below 0°C to give ethoxy trimethylsilane and tris(1,2-dimethoxyethane-O,O′)lithium 2λ³-phosphaethynylsulfanide – [P≡C? S]^? [Li(dme)₃]⁺ – ( 1a ). Apart from bis(trimethylsilyl)sulfane or carbon oxide sulfide, dark red concentrated solutions of λ³-phosphaalkyne 1 are also obtained from reactions of carbon disulfide with bis(tetrahydrofuran)-lithium bis(trimethylsilyl)phosphanide or with the homologous lithoxy-methylidynephosphane ( 2 ) [1]. The ir spectrum shows two absorptions at 1762 and 747 cm^?1 characteristic for the P≡C and C? S stretching vibrations. The nmr parameters {δ(³¹P) ? 121.3; δ(¹³C) 190.8 ppm; ¹J_CP 18.2 Hz} resemble much more values of diorganylamino-2λ³-phosphaalkynes than those of bis(1,2-dimethoxyethane-O,O′)lithoxy-methylidyne-phosphane ( 2a ). As found by an X-ray structure analysis (P2₁/c; a = 1192.6(16); b = 1239.1(19); c = 1414.8(26) pm; β = 105.91(13)° at ?100 ± 3°C; Z = 4 formula units; wR = 0.064) of pale yellow crystals (mp. + 16°C) isolated from the reaction with O,O′-diethyl thiocarbonate, the solid is built up of separate [P≡C? S]^? and [Li(dme)₃]⁺ ions. Typical bond lengths and angles are: P≡C 155.5(11); C? S 162.0(11); Li? O 206.4(17) to 220.3(20) pm; P≡C? S 178.9(7)°.     

Investigations of a highly crowded phosphino-substituted biphenyl: A precursor for a λ3, λ5-diphosphaphenanthrene

The synthesis of 2,2′-bis(bis(dimethylamino)-phosphino)-3,3′5,5′-tetra-tert-butylbiphennyl ( 5 ) is described. It was extensively studied by ¹H, ¹³C, and ³¹P NMR spectroscopy. Furthermore, the X-ray analysis of 5 is reported. Crystals of 5 are tetragonal, space group P¯42₁c, a = b = 24.770 (3) Å, c = 12.658 (4) Å, Z = 8. The surprising reaction of 5 with 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-diphosphaphenanthrene ( 19 ) was obtained.     

Synthese,Eigenschaften und NMR-spektroskopische Untersuchungen an 2,4-Dithioxo-2,4-dimercapto-1,3-diaza-2λ5,4λ5-diphosphetidinen

Synthesis, Properties and N.M.R. Spectroscopic Studies of 2,4-Dithioxo-2,4-dimercapto-1,3-diaza-2λ⁵,4λ⁵-diphosphetidines On the reaction of py · PS₂Cl ( 1 ) or py · PS₂F ( 2 ) (py = Pyridine) with hexamethyl disilazane in a molar ratio of 1:1 the pyridinium salt of the 1,3-bis(trimethylsilyl)-2,4-dimercapto-2,4-dithioxo-1,3-diaza-2λ⁵, 4λ⁵-diphosphetidine ( 3 ) is formed. 3 reacts with MeI to the corresponding methyl ester 9 . There exist two isomers of 9 , probable with cis and trans configuration of the MeS groups, respectively. 3 and 9 have been characterized by i.r., Raman, mass, and NMR spectroscopy. 4 reacts in acetonitrilic solution in the presence of water under hydrolytic cleavage of the trimethyl silyl groups whereas the P₂N₂ ring is preserved. The hydrolysis of 9 has been studied by ¹H-, ³¹P-, and ¹³C-NMR spectroscopy.     

2′, 3′-Dideoxy-3′-fluorotubercidin and Related Dideoxyribonucleosides:. Synthesis via a 2′-deoxy-3′-oxoribofuranoside intermediate and conformation studies

An efficient synthesis of the unknown 2′-deoxy-D-threo-tubercidin ( 1b ) and 2′, 3′-dideoxy-3′-fluorotubercidin ( 2 ) as well as of the related nucleosides 9a, b and 10b is described. Reaction of 4-chloro-7-(2-deoxy-β-D-erythro-pentofuranosyl)-7H-pyrrolo[2,3-d]pyrimidine ( 5 ) with (tert-butyl)diphenylsilyl chloride yielded 6 which gave the 3′-keto nucleoside 7 upon oxidation at C(3′). Stereoselective NaBH₄ reduction (→ 8 ) followed by deprotection with Bu₄NF(→ 9a )and nucleophilic displacement at C(6) afforded 1b as well as 7-deaza-2′-deoxy-D-threo-inosine ( 9b ). Mesylation of 4-chloro-7-{2-deoxy-5-O-[(tert-butyl)diphenylsilyl]-β-D-threo-pentofuranosyl}-7H-pyrrolo[2,3-d]-pyrimidine ( 8 ), treatment with Bu₄NF (→ 12a ) and 4-halogene displacement gave 2′, 3′-didehydro-2′, 3′-dideoxy-tubercidin ( 3 ) as well as 2′, 3′-didehydro-2′, 3′-dideoxy-7-deazainosne ( 12c ). On the other hand, 2′, 3′-dideoxy-3′-fluorotubercidin ( 2 ) resulted from 8 by treatment with diethylamino sulfurtrifluoride (→ 10a ), subsequent 5′-de-protection with Bu₄NF (→ 10b ), and Cl/NH₂ displacement. ¹H-NOE difference spectroscopy in combination with force-field calculations on the sugar-modified tubercidin derivatives 1b , 2 , and 3 revealed a transition of the sugar puckering from the ^3′T_2′ conformation for 1b via a planar furanose ring for 3 to the usual ^2′T_3′ conformation for 2.     

Synthese von Fluoro-λ5-monophosphazenen und Fluoro-1, 3-diaza-2λ5, 4λ5-diphosphetidinen mittels der Staudinger-Reaktion

Synthesis of Fluoro-λ⁵-monophosphazenes and Fluoro-1,3-diaza-2λ⁵,4λ⁵-diphosphetidines by Means of the Staudinger Reaction 35 Tetrafluoro- and 2 difluorodiaza-diphosphetidines as well as 4 difluoro- and 30 monofluoro-λ⁵-monophosphazenes were prepared by the Staudinger reaction between tervalent phosphorus fluorides, R_nPF_3?n (n = 1, 2; R = R₂N, (CH₂)₅N, O(CH₂)₄N, RO, (CH₂O)₂, alkyl, aryl) and phenylazides, X? C₆H₄N₃ (X = H, 4-CH₃, 4-Cl, 4-Br, 4-NO₂, 3-NO₂). PF₃ does not react with phenylazide The influence of substituents on the structure of the reaction products is discussed. Kinetic measurements allowed to determine the constants λ^P_I of the substituents (CH₂)₅N, O(CH₂)₄N and R(C₆H₅)N (R = CH₃, C₂H₅, n-C₄H₉).     

Cyclische Diazastannylene. XV [1]. Charakterisierung einer instabilen Zwischenstufe: 1,3-Di-tert-butyl-2,2-dimethyl-4-tert-butylammonium-1,3,2,4λ3-diazasilastannatetidin

Cyclic Diazastannylenes. XV. Characterization of an Unstable Intermediate: 1,3-Di-tert-butyl-2,2-dimethyl-4-tert-butyl-ammonium-1,3,2,4λ³-diazasilastannatetidine The primary step in the reaction of 1, 3-di-tert-butyl-2,2-dimethyl-1,3,2,4λ²-diazasilastannetidine ( 1 ) with tert-butylamine is the formation of the Lewis-acid-base adduct 5 . In 5 the electrophilic tin atom of 1 is coordinated by the nucleophilic nitrogen atom of the tert-butylamine. 5 crystallizes below ?110°C in a triclinic cell with dimensions (conventional cell see Table 2): a = 1034(4), b = 1492(5), c = 654(3) pm, α= 89.9(3), β = 96.8(3), γ = 91.6(3)°, Z = 2. Above ?110°C the triclinic phase of 5 can be transformed to a monoclinic one (space group P2₁/m) with cell dimensions a = 1048(3), b = 1513(4), c = 654(2) pm, β = 96.9(3)°, Z = 2. An X-ray structural investigation of the latter phase reveals the adduct 5 to have C_S(m)-point symmetry. Important molecular dimensions are the rather long donor bond Sn→N of 242(3) pm, the Sn? N distances within the ring of 211(2) pm and the trigonal pyramidal coordination of the tin atom with mean N? Sn? N angles of 82.3°. The nitrogen atoms of the ring are pyramidal disturbing the planarity of the ring by a bending of 12°. This geometry is due to intramolecular N? H contacts (～290 pm) of the amino-hydrogen atoms with the nitrogen atoms of the ring. Some conclusions for the reaction path can be drawn from the structure of 5 .     

Organylarsino-substituierte Schwefeldiimide: Die Kristallstrukturanalysen von 3, 7-Di-t-butyl-3H, 7H,-1λ4, 5λ4, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocin und Bis(diphenylarsino)schwefeldiimid

Organoarsino-Substituted Sulphur Diimides: Crystal Structure Analyses of 3, 7-Di-t-butyl-3H, 7H-1λ⁴, 5λ⁴, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocine and Bis (diphenylarsino)sulphur Diimide Reaction of the salt K₂SN₂ with organoarsenic chlorides leads to sulphur diimides containing organoarsino substituents at both ends. Single crystal X-ray structure analyses were carried out for two typical compounds, i.e. the cyclic eight-membered 3, 7-di-t-butyl-3H, 7H-1λ⁴, 5λ⁴, 2, 4, 6, 8, 3, 7-dithiatetrazadiarsocine ( 1a , prepared from K₂SN₂ and (t-Bu)AsCl₂ (1:1)) and the open-chain bis(diphenylarsino)sulphur diimide ( 2a , prepared from K₂SN₂ and Ph₂AsCl (1:2)). In both compounds the sulphur diimide groups are coplanar with their directly bound arsenic atoms. This coplanarity principle leads, in the case of 1a , to about conformation (mm2(C_2v) symmetry) of the eight-membered heterocycle; the t-butyl substituents occupy quasi equatorial positions. Small deviations from mm2 symmetry and torsions around the S?N bonds up to 12° can be explained as a consequence of the transnnular repulsion of the lone pairs at the arsenic atoms (As …As distance 3.683(1) Å). In the case of the open-chain S(N? AsPh₂)₂ ( 2a , 2(C₂) symmetry), a cis, cis configuration was found at the S?N double bonds which indicates As…As interaction. The As…As distance (3.379(1) Å) is shorter than in 1a and parallells a reduced interaction of the lone pairs at the As atoms. The S?N bond lenghts (1.517(5) Å in 1 a and 1.521(3) Å in 2a ) are characteristic of sulphur diimides withoug significant π-interaction with the substituents and correspond to S^IV?N double bonds.     

Mono- und Bis(difluorphosphoranyl)ethylen,n-Hexyliden-fluorphosphoran und ein 2,4-Di-n-pentyl-1λ5,3λ5-diphosphet

Mono- and Bis(difluorophosphoranyl)ethylene, n-Hexylidene-fluorophosphorane, and a 2,4-Di-n-pentyl-1λ⁵, 3λ⁵ -diphosphete Bis(diethylamino)phosphanylethylene, 1 , is converted by SF₄ into bis(diethylamino)difluorophosphoranylethylene, 2. Analogously trans-1,2-bis(diphenylphosphanyl)ethylene, 3 , is converted into trans-1,2-bis(difluorodiphenylphoranyl)ethylene, 4. 2 reacts with n-butyllithium to give n-hexylidene-bis(diethylamino)fluorophosphorane, 5. With more n-butyllithium, the main product n-hexylidene-bis(diethylamino)-n-butylphosphorane, 7 , and the by-product 2,4-di-n-pentyl-1,1,3,3-tetrakis(diethylamino)-1λ⁵, 3λ⁵ -diphosphete, 8 , are formed. With t-butyllithium 2 yields 3,3-dimethyl-butylidene-bis(diethylamino)fluorophosphorane, 6. All new compounds 1, 2, 4–8 are characterized by their nmr and ir spectra.     

Preparation,spectral characterization,and single crystal X-ray structures of cis and trans isomers of 2,4,6-trifluoroethoxy-1,3,5-triethyl-1,3,5,2λ5, 4λ5, 6λ5-triazatriphosphorinane-2,4,6-trioxide, [ETNP(O)(OCH2CF3)]3

Oxidation of the cis isomer of the λ³-cyclotriphosphazane [EtNP(OCH₂CF₃)]₃ with trimethylamine-N-oxide (TMNO) gives the cis isomer of trioxo-λ⁵-cyclotriphosphazane [EtNP(O)(OCH₂CF₃)]₃; the trans isomer of [EtNP(O)(OCH₂CF₃)]₃ is obtained by the treatment of a cis and trans mixture of [EtNP(OCH₂CF₃)]₃ with aqueous H₂O₂. The two trioxocyclotriphosphazanes have been characterized by elemental analysis, IR, and NMR (¹H, ¹³C, ¹⁹F, and ³¹P) spectroscopy. The solid state structures of both the isomers have been determined by single crystal X-ray diffraction. The six-membered P₃N₃ ring in both the isomers exhibits a twist-boat conformation; in the cis isomer, the trifluoroethoxy substituents lie on the same side of the ring, whereas, in the trans isomer, two trifluoroethoxy groups are on one side of the ring and the third on the other side of the ring. Crystal data for cis-[EtNP(O)(OCH₂CF₃)]₃: monoclinic, P 2₁/ n , a = 13.593(3), b = 9.721(2), c = 17.539(3) Å, β = 99.49(2)°, V = 2286(1) ų, Z = 4, and Final R = 0.047. Crystal data for trans-[EtNP(O)(OCH₂CF₃)]₃: monoclinic, P 2₁/ n , a = 11.685(4), b = 15.115(5), c = 13.233(5) Å, - = 102.21(3)°, V = 2284(1) ų, Z = 4, and Final R = 0.078.     

Röntgenstrukturanalyse des 1,3-Bis(diethylamino)-1,3-dibenzyl-2,4-diphenyl-1λ5, 3λ5-diphosphets

X-Ray Crystal Structure Determination of 1,3-Bis(diethylamino)-1,3-dibenzyl-2,4-diphenyl-1λ⁵, 3λ⁵-diphosphete Benzylidene-diethylamino-benzylfuorophosphorane, 1 , reacts with lithium bis(trimethylsilyl)amide to give the title compounds 2 and 1-diethylamino-2,3-diphenylphosphirane, 3 . Only one of the stereoisomers of 2 is formed in which the two benzyl groups are located on the same side of the planar four-membered ring. 2 crystallizes in the monoclinic space group P2₁/n.     

P,P′-(2,5-Dihydroxy-3,6-dimethyl-2,5-dioxo-2λ5,5λ5-[1,4,2,5]-dioxadiphosphinan-2,5-diyl)-bis-phosphonsäure

P,P′-(2,5-Dihydroxy-3,6-dimethyl-2,5-dioxo-2λ⁵,5λ⁵-[1,4,2,5]dioxadiphosphinane-2,5-diyl)-bis-phosphonic Acid The tetrahydrate 1 of the title compound crystallizes in the monoclinic space group P2₁/c with a = 845.8, b = 1 098, c = 981.7 pm, β = 113.02° and Z = 2. The anions of the oxonium compound (H₃O⁺ · H₂O)₂(C₄H₁₀O₁₂P₄^2?) are layered by hydrogen bridges. The ¹H, ¹³C and ³¹P NMR spectra (4 and 5 spin systems) are discussed.     

Synthese und NMR-Spektren von λ5-Diphospheten Die Struktur des 2,4-Diphenyl-1,1,3,3-tetrakis(diethylamino)-1λ5,3λ5-diphosphets

Synthesis and NMR Spectra of λ⁵-Diphosphets. Structure of 2,4-Diphenyl-1,1,3,3-tetrakis (diethylamino)-1λ⁵, 3λ⁵-diphosphete Preparation, properties, and n.m.r. spectra of C₂H₅PF₂[N(C₂H₅)₂]₂, CH₂?PF[N(C₂H₅)₂]₂, and the diphosphetes {RC?P[N(C₂H₅)₂]₂}₂ (R) ? H ( 5a ), CH₃ [( 5b )] are described. The λ⁵-diphosphete {HC?P(NR₂)₂}₂ (R ? CH₃) reacts with BF₃ · O(C₂H₅)₂ to give which is transformed into by n-C₄H₉Li. The crystal and molecular structure of 2,4-diphenyl-1,3,3-tetrakis(diethylamino)-1λ⁵,3λ⁵-diphosphete 2 are reported and discussed.     

Synthese und Struktur von Lithium-tris(trimethylsilyl)silanid · 1,5 DME

Synthesis and Structure of Lithium Tris(trimethylsilyl)silanide · 1,5 DME Lithium tris(trimethylsilyl)silanide · 1,5 DME 2a synthesized from tetrakis(trimethylsilyl)silane 1 [6] and methyllithium in 1,2-dimethoxyethane , crystallizes in the monoclinic space group P2₁/c with following dimensions of the unit cell determined at a temperature of measurement of ?120 ± 2°C: a = 1 072.9(3); b = 1 408.3(4); c = 1 775.1(5) pm; β = 107.74(2)°; 4 formula units (Z = 2). An X-ray structure determination (R_w = 0.040) shows the compound to be built up from two [lithium tris(trimethylsilyl)silanide] moieties which are connected via a bridging DME molecule. Two remaining sites of each four-coordinate lithium atom are occupied by a chelating DME ligand. The Li? Si distance of 263 pm is considerably longer than the sum of covalent radii; further characteristic mean bond lengths and angles are: Si? Si 234, Li? O 200, O? C 144, O?O (biß) 264 pm; Si? Si? Si 104°, Li? Si? Si 107° to 126°; O? Li? O (inside the chelate ring) 83°. Unfortunately, di(tert-butyl)bis(trimethylsilyl)silane 17 prepared from di(tert-butyl)dichlorsilane 15 , chlorotrimethylsilane and lithium, does not react with alkyllithium compounds to give the analogous silanide.     

Mono‐ and Binuclear Rhodium and Platinum Complexes of 1, 3, 5‐Trimethyl‐1, 3, 5‐triaza‐2σ3λ3‐phosphorin‐4, 6‐dionyloxy‐substituted Calix[4]arenes

The reaction behaviour of 1, 3, 5‐triaza‐2σ³λ³‐phosphorin‐4, 6‐dionyloxy‐substituted calix[4]arenes towards mono‐ and binuclear rhodium and platinum complexes was investigated. Special attention was directed to structure and dynamic behaviour of the products in solution and in the solid state. Depending on the molar ratio of the reactands, the reaction of the tetrakis(triazaphosphorindionyloxy)‐substituted calix[4]arene ( 4 ) and its tert‐butyl‐derivative ( 1 ) with [(cod)RhCl]₂ yielded the mono‐ and disubstituted binuclear rhodium complexes 2 , 3 , and 5 . In all cases, a C₂‐symmetrical structure was proved in solution, apparently caused by a fast intramolecular exchange process between cone conformation and 1, 3‐alternating conformation. The X‐ray crystal structure determination of 5 confirmed [(calixarene)RhCl]₂‐coordination through two opposite phosphorus atoms with a P ⃜P separation of 345 pm. The complex displays crystallographic inversion symmetry, and the Rh₂Cl₂ core is thus exactly planar. Reaction of 1 and of the bis(triazaphosphorindionyloxy)‐bis(methoxy)‐substituted tert‐butyl‐calix‐[4]arene ( 7 ) with (cod)Rh(acac) in equimolar ratio and subsequent reaction with HBF₄ led to the expected cationic monorhodium complexes 5 and 8 , involving 1, 3‐alternating P‐Rh‐P‐coordination. The cone conformation in solution was proved by NMR spectroscopy and characteristic values of the ¹J(PRh) coupling constants in the ³¹P‐NMR‐spectra. Reaction of equimolar amounts of 4 with (cod)Rh(acac) or (nbd)Rh(acac) led, by substitution of the labile coordinated acetylacetonato and after addition of HBF₄, to the corresponding mononuclear cationic complexes 9 and 10 . Only two of the four phosphorus atoms in 9 and 10 are coordinated to the central metal atom. Displacement of either cycloocta‐1, 5‐diene or norbornadiene was not observed. For both compounds, the cone conformation was proved by NMR spectroscopy. Reaction of 4 with (cod)PtCl₂ led to the PtCl₂‐complex ( 11 ). As for all compounds mentioned above, only two phosphorus atoms of the ligand coordinate to platinum, while two phosphorus atoms remain uncoordinated (proved by δ³¹P and characteristic values of ¹J(PPt)). NMR‐spectroscopic evidence was found for the existence of the cone conformation in the cis‐configuration of 11 .