Showing papers by "Peter G. Jones published in 1990"

Synthesis of intermediates in the C–H activation of acetone with 2-phenylazophenylgold(III) complexes and in the C–C coupling of aryl groups from diarylgold(III) complexes. Crystal and molecular structures of [Au{C6H3(NNC6H4Me-4′)-2-Me-5}(acac-C)Cl](acac = acetylacetonate), cis-[Au(C6H4NNPh-2)Cl2(PPh3)], and [Au(C6H4CH2NMe2-2)(C6F5)Cl]

Abstract: The complex [[graphic omitted]Ph-2)Cl2] reacts with [HgR2](R = C6H4NO2-2 or C6F5) and NMe4Cl (2 : 1 : 2) to give [[graphic omitted]Ph-2)(R)Cl][R = C6H4NO2-2, (1); or C6F5(2)]. Similarly, [[graphic omitted])Cl2](3)[C–N = C6H3(NNC6H4Me-4′)-2-Me-5], prepared by the reaction of [AuCl3(tht)](tht = tetrahydrothiophene) with [Hg(C–N)Cl] and NMe4Cl (1 : 1 : 1), reacts with Tl(acac)(Hacac =acetylacetone)(1 : 1) to give [[graphic omitted])(acac-C)Cl](4). Reaction of (2) with PPh3(1 : 1) leads to [[graphic omitted]Ph-2)(C6F5)Cl(PPh3)](5), which upon standing in dichloromethane solution decomposes to give a mixture of [Au(C6F5)(PPh3)], C6H4C6F5-1 -NNPh-2, and [Au(C6H4NNPh-2)Cl2(PPh3)](6). Crystal structures were determined for complexes (4), (6), and [[graphic omitted]Me2-2)(C6F5)Cl](7)[(4), space group P, a= 9.475(4), b= 9.923(4), c= 10.913(4)A, α= 63.75(3), β= 84.92(3), γ= 89.41 (3)°, Z= 2, R= 0.020 for 3 057 reflections at –95 °C; (6), space group P21/n, a= 10.361(3), b= 28.194(8), c= 10.724(4)A, β= 116.26(2)°, Z= 4, R= 0.038 for 3 734 reflections at 20 °C; (7), space group Pbca, a= 11.996(4), b= 14.484(4), c= 18.310(7)A, Z= 8, R= 0.045 for 1 909 reflections at 20 °C]. The three structures reveal neutral molecules with square-planar geometry around the gold atom. In complexes (4) and (7) the aryl groups act as chelating ligands, forming a five-membered ring [(4), Au–C 2.026(4), Au–N 2.158(3)A; (7), Au–C 2.022(10), Au–N 2.128(10), Au–C6F5 2.012(11)A] while in complex (6) the aryl group acts as a monodentate ligand [Au–C 2.033(5)A]. The chloro ligand in complex (4) is trans to the carbon atom of the aryl ligand [Au–Cl 2.349(2)A], and the acac ligand is C-bonded to the gold atom [Au–C 2.083(4)A]. This is one of the few isolated acetylacetonatogold(III) complexes and the first structurally characterized. In complex (6), chloro atoms are mutually cis[Au–Cl (trans to C) 2.377(2), (trans to N) 2.325(2)A]. The chloro ligand in complex (7) is trans to the aryl group of the chelating ligand [Au–Cl 2.347(3)A]. The isolation of complexes (1) and (2) and the observed geometry of (4) support the pathway suggested for the C–H activation of acetone with 2-phenylazophenylgold(III) complexes.

Gold complexes with selenium ligands, I. Preparation and crystal structures of phenylselenolato‐gold(I) complexes

Abstract: (Triphenylphosphine)phenylselenolatogold(I), Ph3PAuSePh (1), and the corresponding dppm derivative, [(dppm)(AuSePh)2] (3), are prepared from Me3SiSePh and the appropriate (phosphine)chlorogold(I) complex. The reaction between Ph3PAuCl, Ph2Se2 and AgSbF6 leads to the salt [(Ph3PAu)2SePh]+SbF−6 (2), with a bridging PhSe ligand. X-ray structure analyses of 1 and 2 confirm the expected linear geometry at gold and reveal short Au-Au contacts; both compounds may thus be regarded as loose dimers.

2,4,6-Trinitrophenylgold(I) complexes. X-Ray crystal structures of [Au(SbPh3)4][Au{C6H2(NO2)3-2,4,6}2]·Et2O and [Au{C6H2(NO2)3-2,4,6}(dmphen)](dmphen = 2,9-dimethyl-1,10-phenanthroline)

Abstract: The reaction of [PPh3(CH2Ph)][AuCl2] in refluxing acetone with [Hg{C6H2(NO2)3-2,4,6}2](1 : 0.55) and excess of NMe4Cl affords NMe4[HgCl3] and [PPh3(CH2Ph)][Au{C6H2(NO2)3-2,4,6}Cl](1). Complex (1) reacts with excess of both NaClO4·H2O and tetrahydrothiophene (tht) at room temperature to give [Au{C6H2(NO2)3-2,4,6}(tht)](2) which reacts with SbPh3(1 : 2) or with excess of 2,9-dimethyl-1,10-phenanthroline (dmphen) to give [Au(SbPh3)4][Au{C6H2(NO2)3-2,4,6}2](3) or [Au{C6H2(NO2)3-2,4,6}(dmphen)](4), respectively. Crystal structures were determined for complexes (3) and (4). That of (3)[space group P21/n, a= 12.320 5(18), b= 35.802(6), c= 19.759(3)A, β= 102.24(2)°, and Z= 4; R= 0.053, R′= 0.051] consists of tetrahedral [Au(SbPh3)4]+ cations (mean Au–Sb bond length 2.651 A), linear [Au{C6H2(NO2)3-2,4,6}2]– anions (Au–C 2.015 and 2.041 A), and diethyl ether of crystallization. The nitro groups display high thermal motion or disorder. The crystal structure of complex (4)[space group P21/c, a= 7.165 8(8), b= 16.976 3(18), c= 16.471 8(24)A, β= 99.80(2)°, and Z= 4; R=R′= 0.023] consists of neutral molecules with geometry intermediate between two- and three-co-ordination (Au–C 2.000, Au–N 2.136, 2.573 A; C–Au–N 168.4°). Both complexes show ipso C–C–C angles much less than the ideal 120°.

Darstellung und Kristallstrukturen einiger mit N,N'‐Dimethylharnstoff verbrückter Diphosphorverbindungen; NMR‐Untersuchung einer λ4P+λ4P+‐Diphosphorverbindung

Abstract: Preparation and Single-Crystal X-ray Structure Investigations of some N,N′-Dimethylurea-Bridged Diphosphorus Compounds: NMR Studies of a λ4P+ λ4P+ -Diphosphorus Compound The synthesis of N,N′-dimethylurea-bridged diphosphorus compounds involving the structural elements λ3Pλ4P+ (3b, 3c, and 7) and λ4P+λ4P+ (4 and 8) is described. The salts 4 and 8 were obtained by methylation of the λ3Pλ4P+ compounds 3c and 7 with MeOSO2CF3. The λ3P atom in 3c and 7 coordinates to tungsten(0) with formation of the ionic pentacarbonyl derivatives 9 and 10. The NMR spectra of the diphosphonium salt 4 were completely analyzed using NOE and 2D shift correlation experiments (13C,1H and 31P,1H). The single crystal X-ray structure determinations of 3b and 9 are reported. 3b found to crystallize as a hemisolvate with dichloromethane. The RR/SS diastereomer is present in the crystal. The PP distance amounts to 219.1 pm. Both phosphorus atoms interact weakly with the chloride ion (293, 312 pm). 9 crystallizes as a hemisolvate with toluene, the RS/SR diastereomer being present. A PP distance of 224.7 pm and weak interactions between the phosphorus atoms and an oxygen atom of the anion (305, 308 pm) are found.

Synthesis of (diphenylphosphinothioyl)methyldiphenylphosphoniomethanide complexes of gold and silver. X-ray structure of [Au(C6F5){SPh2PCH-[Au(C6F5)]PPh2Me}]

Abstract: Both [Au(C6F5)3(SPh2PCHPPh2Me)]{obtained from [Au(C6F5)3(OEt2)] and [SPh2PCH2PPh2Me]ClO4, followed by deprotonation with NaH} and the free methanide SPPh2CHPPh2Me react with gold(I) or silver(I) complexes [Au(C6F5)(tht)](tht = tetrahydrothiophene), [Au(tht)2]ClO4, and [Ag(OClO3)(PPh3)] to afford binuclear complexes of the types [Au(C6F5){SPh2 PCH[Au(C6F5)]PPh2Me}] or [{M(SPh2PCHPPh2Me)}2][ClO4]2(M = Au or Ag). The silver complex can also be obtained by deprotonation of [{Ag(SPh2PCH2PPh2Me)}2][ClO4]2 with Na2CO3. Oxidative addition of chlorine to the gold derivative gives the binuclear gold(II) complex [{AuCl(SPh2PCHPPh2Me)}2]. The structure of [Au(C6F5){SPh2PCH[Au(C6F5)] PPh2Me}] has been established by X-ray crystallography [space group P21/c, with a= 15.392(4), b= 12.643(5), c= 21.965(7)A, β= 107.95(2)°, and R′= 0.072 for 3 166 unique observed reflections]. The molecule adopts a folded conformation with parallel, eclipsed C6F5 rings and a corresponding short Au ⋯ Au contact of 3.224 A.

Synthesis of mono- and di-nuclear palladium(II) complexes containing ylide ligands [PPh2(CHCO2R)2]–(R = Me or Et). Crystal structures of [Pd{(CHCO2Et)2PPh2}2], [Pd{(CHCO2Et)2PPh2}Cl(PPh3)], and [Pd{(CHCO2Et)2PPh2}(NC5H5)2]ClO4

Abstract: Complexes [Ag2{µ-(CHCO2R)2PPh2}2](R = Me or Et) react (1:1) with trans-[PdCl2(NCPh)2] to give spirane complexes [Pd{(CHCO2R)2PPh2}2][R = Me, (1a); or Et, (1b)] which, in turn, react with PdCl2(1 : 1) to give [Pd2{(CHCO2R)2PPh2}2(µ-Cl)2][R = Me, (2a); or Et, (2b)]. Complex (1a) can also be obtained by treating (2a) with [Ag2{µ-(CHCO2Me)2PPh2}2](1 : 1). Complexes (2a) and (2b) react with neutral ligands to yield [Pd{(CHCO2R)2PPh2}ClL][R = Me, L = pyridine (py), (3a), or PPh3, (4a); R = Et, L = py, (3b), or PPh3, (4b)] or with neutral ligands in the presence of NaClO4to give [Pd{(CHCO2R)2PPh2}L2]ClO4[R = Me, L2= 2,2′-bipyridyl, (5a), or 1,2-bis(diphenyl-phosphino)ethane, (6a); R = Et, L = py, (7b)]. When (2a) is treated with TI(acac)(Hacac = acetylactone) or TI(cp)(cp = cyclopentadienyl)(1 : 2), [Pd{(CHCO2Me)2PPh2}(acac)](8a) or [Pd{(CHCO2Me)2PPh2}(η-cp)](9a) are obtained, respectively. The X-ray structures of complexes (1b)(which displays crystallographic inversion symmetry), (4b), and (7b) have been determined, showing a chelating co-ordination of all ylide ligands, the methine carbon donor atoms of which adopt RR or SS configurations. The chelate rings are non-planar. The Pd–C bond lengths reflect the various trans influences.

Tetrakis(organodifluorophosphine)platinum(o) and bis(arylphosphonofluoridite)-bis(arylphosphonofluoridous acid)-platinum(ii) complexes

Abstract: The reaction of potassium tetrachloroplatinate (II) with tert-butyldifluorophosphine, phenyldifluorophosphine, and 2,5-dimethylphenyldifluorophosphine under mild conditions led to the formation of tetrakis-(organodifluorophosphine) platinum(0) complexes. A combined partial hydrolysis and oxidation reaction of the tetrakis(aryldifluorophosphine) platinum(0) complexes furnished bis(arylphosphonofluoridite)-bis(arylphosphonofluoridous acid) platinum(II) complexes

Cyclophanes, XXXV. DNMR, molecular mechanics, and crystal structures of 2,11-dithia[3.3]orthometacyclophane and 2,11-dithia[3.3]orthoparacyclophane

Abstract: The syntheses of 2,11-dithia[3,3]orthometacyclophane (5) and 2,11-dithia[3,3]orthoparacyclophane (6) by dithiol-dibromide coupling are described. Whereas the yield of 5 is not significantly affected by the substrate pairing, that of 6 is. Both compounds exhibit a temperature-dependent 1H-NMR spectrum. An energy barrier of 11.0 ± 0.2 kcal/mol (45.7 ± 0.8 kJ/mol) has been calculated for 5, but that of 6 was too low to be determined. Slightly contrasting results were obtained from two different molecular mechanics programs for the relative energies of the six limiting conformations of 5. Crystal structure determinations of 5 and 6 have been carried out, and the conformational behavior of 5 and 6 in solution and in the solid state is discussed.

Notizen / Notes. Eine neue Bildungsweise der Phosphor – Phosphor‐Bindung. Kristallstrukturanalyse von Tetramethyldiphosphanmonosulfid

Abstract: A New Mode of Formation of a Phosphorus - Phosphorus Bond. X-ray Crystal Structure of Tetramethyldiphosphane Monosulfide Tetraphenyldiphosphane monosulfide (7) was formed during an attempt to synthesize the diphenylphosphino-substituted thioureas 5 and 6 by the reaction of thiourea (1) or N,N′-bis-(trimethylsilyl)thiourea (2) with chlorodiphenylphosphane. The attempted distillation of the dimethylphosphino-substituted N,N′-dimethylthiourea 9 furnished tetramethyldiphos-phane monosulfide (10). These reactions provide a new mode of formation of phosphorus – phosphorus bonds. – According to an X-ray analysis, 10 crystallizes in the space group P21/n. The molecule adopts a trans configuration, with the S atom antiperiplanar to the lone pair.

Modelling the reduction of nitrobenzene with [Ru3(CO)12] as a homogeneous catalyst. X-Ray structures of [Ru3H(CO)10(PhNH)] and [N(PPh3)2][Ru3H(CO)9(PhN)]

Abstract: The ability of [Ru3(CO)12] to act as a homogeneous catalyst in the reductive carbonylation of nitrobenzene has been confirmed. Under the conditions used in the catalytic runs the reactivities of the six clusters [Ru3(CO)10(µ3-PhN)](1), [Ru3H(CO)10(PhNH)](2), [Ru3H2(CO)9(µ3-PhN)](3), [Ru3H(CO)9(µ3-PhNCO)]–(4), [Ru3H(CO)9(µ3-PhN)]–(5), and [Ru3(CO)10(µ-PhNCHO)]–(6) are described. The syntheses of (4)–(6) and the X-ray structures of (2) and (5a), the [N(PPh3)2]+ salt of (5), are also discussed. The conversion of complex (4) into (5) has been studied kinetically. The activation parameters and a Hammett correlation for this reaction are reported. From the observed reactivities of (1)–(6), two model catalytic cycles for catalytic systems with or without OR–(R = H or Me) as promoters have been proposed. Clusters (4) and (6) are probable catalytic intermediates in RO–-promoted catalytic runs.

Studies on [Ru3(CO)12]-catalysed homogeneous transfer hydrogenation reactions; X-ray structure of [Ru4(CO)10Cl12(OPh)2]

Abstract: Using [Ru3(CO)12](1) as the homogeneous precatalyst, transfer hydrogenations of cyclohex-2-en-1-one, benzylideneaniline, and carbon tetrahalides by donor alcohols, in particular propan-2-ol, have been studied. Conversion of cyclohex-2-en-1-one into cyclohexanol has been found to proceed via the intermediate formation of cyclohexanone. From the temperature dependence of the overall reaction rates, the precatalysts [Ru3(CO)12] and [Ru4H4(CO)12] are involved in processes with comparable activation energies. Two catalytically active cluster complexes, [Ru4(CO)12(C6H6O)] and [Ru3(CO)10(C6H8O)], were isolated from the reaction of (1) with cyclohex-2-en-1-one. Hydrogenation of the tetranuclear cluster led to the formation of [Ru4H4(CO)12] and [Ru3H2(CO)9(C6H8O)]. The reaction of complex (1) with benzylideneaniline gave a catalytically active cluster [Ru3H(CO)9(PhNCPh)]. With (1) as the precatalyst, analogues of benzylideneaniline of general formula RC6H4CHNPh can all be transfer hydrogenated, with the exception of the o-methoxy derivative. The complex [Ru3H(CO)9(PhNCPh)] was found to undergo reversible carbonylation. Rational syntheses for [Ru3(CO)7X2(OR)2] and [Ru4(CO)10X2(OR)2] were designed by treating (1) with the appropriate alcohol and carbon tetrahalide. The X-ray structure of [Ru4(CO)10Cl2(OPh)2] has been determined. The halogenoalkoxo clusters are considered to be active intermediates in the overall catalytic cycle for the transfer hydrogenations of carbon tetrahalides.

Intramolekulare Donator‐Akzeptorwechselwirkungen in λ4P(V)‐Verbindungen Phosphor(V)‐Derivate des N,N,N′‐Trimethylethylendiamins

Abstract: Intramolecular Donor-Acceptor Interactions in λ4P(V) Compounds. — Phosphorus(V) Derivatives of N,N,N′-Trimethyl-ethylenediamine The chlorophosphino derivative of N,N,N′-trimethylethyl-enediamine Me2NCH2CH2(Me)NP(Cl)Me (1) and the 2-(diethylamino)-λ3-phospholidinium salt [Me2 NEt2]+ Cl− (5) have been allowed to react with several oxidizing agents. Reaction of 1 with dimethyl sulfoxide furnishes the phosphonamidic chloride Me2NCH2CH2(Me)NP(O)(Cl)Me (3) while with elemental sulfur the phosphonamidothioic chloride Me2NCH2CH2(Me)NP(S)(Cl)Me (2) is obtained. The reaction of 2 with sodium tetraphenylborate furnished the 1,1,2,3-tetramethyl-1,3,2-λ4-diazaphospholidinium tetraphenylborate [Me2 (S)Me]+ [BPh4]− (4). The reaction of 5 with phenyl azide, followed by sodium tetraphenylborate led to 2-(diethylamino)-2-(phenylimino)-1,3,2λ4-diazaphospholidinium tetraphenylborate [Me2 (NPh)NEt2]+ [BPh4]−1 (7). The methoxy-λ3-diazaphospholidinium salt [Me2 OMe]+ [BPh4]− (6) does not react with phenyl azide to produce the 2-methoxy-2-(phenylimino)-1,3,2λ4-diaza-phospholidinium salt analogous to 7; instead its rearrangement product, the dimeric 1,3,2λ4,4λ4-diazadiphosphetidine tetraphenylborate [Me3NCH2CH2(Me)NP(O)NPh]2[BPh4]− (8), is isolated in low yield. Singlecrystal X-ray structure determinations of 4 and 8 are described.

VERBINDUNGEN MIT DEM 1,3-DIMETHYL-1,3- DIAZA-2-PHOSPHETIDIN-4-ON GRUNDGERüST: SYNTHESE VON 1,3-DIMETHYL-2-PHENYLIMINO- 1,3-DIAZA-2λ4-PHOSPHETIDIN-4-ON-DERIVATEN. RÖNTGENSTRUKTURANALYSE VON 4,6- DIMETHOXY -5,10-DIPHENYL-1,3,7,9- TETRAMETHYL-l,3,5,7,9,10-HEXAAZA- 4λ5,6λ55-DIPHOSPHADISPIRO[3.1.3.1]DECAN-2,8-DION

Abstract: Die Umsetzung einer Reihe von λ3P-Diazaphosphetidinonen, MeNC(:O)N(Me)PY (Y [dbnd] NEt2: 1, N(CH2)4; 2, NPh2; 3, OMe; 4, N(cyc)2; 5), mit Phenylazid wird beschrieben. Die dabei primar entstandenen 2-Phenylimino-λ4P-diazaphosphetidinone, MeNC(:O)N(Me)P(:NPh)Y sind mit Ausnahme des sterisch anspruchsvollen Dicyclohexylderivats, Y [dbnd] N(cyc)2; 12, unbestandig und dimerisieren rasch zu den entsprechenden Diazadiphosphetidinen, 7 und 9–11. Aus 7 bildet sich in Losung unter Abspaltung von MeN[dbnd]C[dbnd]NMe das A4P, λ4P,λ5P-Diazadiphosphetidin 8. Die neuen Verbindungen 8–12 wurden analytisch, 1H-, 13C- und 31P-NMR-spektroskopisch sowie durch ihre Massenspektren charakterisiert. Daruber hinaus wurde von Verbindung 11 eine Rontgenstrukturanalyse durchgefuhrt. Das Molekul besitzt kristallographische zweizahlige Symmetric. Die Geometrie am Phosphor ist verzerrt trigonal bipyramidal, mit P—N-Bindungslangen 173.9. 179.2 pm (axial) sowie 168.3, 168.7 pm (aquatorial). Compounds involving the 1,3-dimethyl-1...

Neue Dienophile und Diene, III. Über die Addition von Cyanacetylen an [2.2]Paracyclophan

Abstract: New Dienophiles and Dienes, III. — On the Addition of Cyanoacetylene to [2.2]Paracyclophane Heating a benzene solution of [2.2]paracyclophane (2) in the presence of excess cyanoacetylene (1b) at 160°C in a sealed ampoule provides the novel 2:1-addition product 10, as well as the previously obtained cycloadducts 7–9. It is suggested that these Nenitzescu hydrocarbon systems are formed via the cyclobutadiene intermediates 17 and 18. This hypothesis is supported by the isolation of the side-products 1,2,4-and 1,2,3-tricyanobenzene (11 and 12). When a mixture of 7 and 8 is pyrolyzed at 220°C the novel dihydronaphthalene 24 is formed; the mechanism of this isomerization is discussed. The structures of 10 and 24 were confirmed by X-ray structure determination.

Notizen: Polysulfonylamine, XIX [1] / Kristallstruktur von (1-AcetyI-4-dimethylaminopyridinium)-dimesylamid bei –90 °C / Polysulfonylamines, XIX Crystal Structure of 1-Acetyl-4-dimethylaminopyridinium Dimesylamide at –90 °C

Abstract: The crystal structure of the title compound was determined at —90 °C. It crystallizes in space group PĪ with a = 772.3(2), b = 1071.2(3), c = 1090.4(4) pm, α = 62.65(2), β = 82.71(2), γ = 71.42(2)° and Z = 2. The final R value was 0.031 for 2368 unique observed reflections. The presence of ion pairs in the solid state is observed, with short contacts of 290 pm between the pyridinium nitrogen and an oxygen of the anion. An analysis of the bond lengths suggests that the resonance form with a double bond to the nitrogen of the dimethylamino group and two localized double bonds in the ring, makes a larger contribution to the overall structure than in several similar pyridinium systems; the carbonyl moiety can however be regarded as containing a pure double bond.

Reaktionsverhalten von Phosphorpentahalogeniden mit Übergangsmetallcarbonyl-Verbindungen. IV [1 - 3]. Das Reaktionsverhalten von Phosphorpentahalogeniden gegenüber [CpM(CO)3]2 (M = Cr, Mo, W) Die Kristallstruktur von CpCrCl2CH3CN

Abstract: Die Reaktion von PX5 mit Cyclopentadienylderivaten des Typs [CpM(CO)3]2 (M = Cr, Mo, W; Cp = 5-C5H5) fuhrt bei Raumtemperatur in hohen Ausbeuten zu den Halogeno-Komplexen CpCrX2CH3CN bzw. CpMX4CH3CN (X = Cl, Br; M = Mo, W). Die erhaltenen Derivate werden anhand der IR- und ESR-Spektroskopie, sowie der Messung magnetischer Daten charakterisiert. CpCrCl2CH3CN kristallisiert in der Raumgruppe P21/c als Monomer mit verzerrter tetraedrischer Geometrie am Chrom. Der Cp-Ring ist ungeordnet.

Kinetics and mechanism of a chemiluminescent clock reaction based on the horseradish peroxidase catalysed oxidation of luminol by hydrogen peroxide

Abstract: In the presence of limited amounts of urate the rapid onset of light emission from the horseradish peroxide catalysed oxidation of luminol by hydrogen peroxide is delayed, yielding a chemi-luminescent clock reaction. Under appropriate conditions the rate of urate oxidation by hydrogen peroxide in the dark reaction is independent of the concentration of both reagents, reflecting a steady state in the catalytic system in which the enzyme intermediate. Compound (II), preferentially reacts with luminol to yield luminol radicals which rapidly oxidise urate. Luminol, therefore, acts as an electron-transfer mediator during the dark reaction and its concentration remains constant, yielding an overall zero-order process.

Properties and Reactions of 3-Aza-l-azonia-l.l,3-trimethyl- 2λ3-phospholidines (Intramolecularly Stabilized Phosphenium Cations)

Abstract: In contrast to the well-known phosphorus(III) donor systems, comparatively few cases are known in which P(III) displays acceptor properties, cf., e.g.1,2. Adducts of the type X3P ← Nu (Nu = nucleophilel are of special Interest as models of nucleophilic substitution reactions at P(III), and have been isolated, in some cases3. Compound 1. reported in 1966 4, probably constitutes the first case of an in-tramolecular complex involving P(III) as acceptor.

Reaktionen von 2,2,4,4‐Tetrakis(trifluormethyl)‐1,3‐dithietan mit KNCS und KNCO – Struktur des Triphenylphosphan‐Gold(I)‐Komplexes eines Thiazolin‐4‐thiolats

Abstract: Reactions of 2.2,4,4-Tetrakis(trifluoromethyl)-1.3-dithietane phosphane Gold(1) Complex of a Thiazoline-4-thiolate with KNCS and KNCO - Crystal Structure of a Triphenyl-phosphane Gold(1) Complex of a Thiazoline-4-thiolate 2,2,4,4-Tetrakis(trifluoromethyl)-1,3-dithietane (1) reacts with KNCS to yield the potassium salt of 4-mercapto-2,2,5,5-tetrakis(trifluoromethyl)-Δ3-thiazoline (2). An oxidative workup procedure results in the formation of the disulfide 6. The salt 2 reacts with methyl bromoacetate, benzyl bromide, 3-bromo-1-phenylpropene, and 1,3-diiodopropane to form the thioethers 3–5 and 7, respectively. Protonation of 2 results in the formation of the thiolactam 9. Disulfide 6 reacts with Cl2 in the presence of FeCl3 to yield the sulfenyl chloride 8. C–S bond formation (10) is observed by treating 8 with Me3SiCN. The gold(I) complex 11 is formed from 2 and Ph3PAuCl. 11 crystallizes in the monoclinic space group P21/n and contains a linear P–Au–S unit. The reaction of 1 with KNCO leads after protonation to the perfluorinated lactam 12 and the cyanuric acid derivative 13.

Über die Darstellung neuer spirocyclischer N,N′-Dimethylsulfamid-substituierter Phosphorverbindungen und Ν,N′-Dimethylsulfamid-verbrückter Diphosphorverbindungen / The Preparation of New Spirocyclic N,N′-Dimethylsulphamide-Substituted Phosphorus Compounds, and of Some N,N′-Dimethylsulphamide-Bridged Diphosphorus Compounds

Abstract: The reactions of 4-chloro-1,3,5,7-tetramethyl-2,2,6,6-tetraoxa-2,6-dithia-1,3,5,7-tetraaza-4λ⁵-phosphaspiro[3.3]heptane (1) with trimethylsilyl compounds and sodium azide led to a series of spirocyclic N,N′-dimethylsulphamide-substituted phosphoranes (2—5). The nature of the pentaaza-spirophosphorane (4) was confirmed by an X-ray crystal structure determination (C2/c, a = 991.8(4), b = 1185.6(6), c = 1224.9(5) pm,β = 108.64(3)°, Z = 4, R = 0.041 for 1065 unique observed reflections); a crystallographic twofold axis passes through phosphorus and the nitrogen atom of the NMe₂ group. The geometry at phosphorus is to a good approximation trigonal bipyramidal. The azido-spirophosphorane (5) undergoes Staudinger-type reactions with phosphorus(III) compounds (PPh₃, dppm) to form the mixed-valence phosphorus compounds 6—8. The reaction of N,N′-dimethylsulphamide or N,N′-dimethyl-N,N′-bis(trimethylsilyl)-sulphamide with dichlorophosphines RPCl₂ (R = Me, Ph) in a molar ratio 1:2 leads to the formation of the acyclic N,N′-dimethylsulphamide-bridged diphosphorus compounds 9 and 10, respectively. The spectroscopic properties (and, for 4, the X-ray crystal structure) of the products are compared with those of analogous urea-bridged phosphorus compounds.

Polysulfonylamine. XX. (1/1)‐Molekülkomplexe von Di(organosulfonyl)aminen mit Triphenylphosphinoxid. Röntgenstrukturanalyse von Dimesylamin‐Triphenylphosphinoxid (1/1)

Abstract: Aus aquimolaren Losungen der jeweiligen Komponenten in organischen Losemitteln werden kristalline Addukte der Zusammensetzung (RSO2)2NH · OP(C6H5)3 mit R = CH3, C6H5, 4-XC6H4 (X = CH3, F, Cl, Br, NO2) sowie 3-NO2C6H4 erhalten. (CH3SO2)2NH · OP(C6H5)3 kristallisiert in der monoklinen Raumgruppe P21/n. Eine kurze Wasserstoffbrucke des Typs NH O [N O 266,1(5) pm] verknupft das Dimesylamin- mit dem Triphenylphosphinoxid-Molekul. Polysulfonyl Amines. XX. (1/1) Molecular Adducts of Di(organosulfonyl) Amines with Triphenylphosphine Oxide. X-Ray Structure Determination of Dimesylamine-Triphenylphosphine Oxide (1/1) From equimolar solutions of the respective components in organic solvents, crystalline addition compounds of composition (RSO2)2NH · OP(C6H5)3 are obtained, where R = CH3, C6H5, 4-XC6H4 (X = CH3, F, Cl, Br, NO2) or 3-NO2C6H4. (CH3SO2)2NH · OP(C6H5)3 crystallizes in the monoclinic space group P21/n. A short NH O hydrogen bond [N O 266.1(5) pm] connects the dimesylamine molecule with the triphenylphosphine oxide molecule.

Absence of effect of dipyridamole on renal and platelet function in diabetes mellitus.

Abstract: We evaluated the effect of dipyridamole (5 mg/kg/day) for 12 months on renal and platelet function in 53 children with insulin dependent diabetes mellitus (IDDM) in a prospective double blind placebo controlled trial. Urine albumin excretion (expressed as the geometric mean albumin to creatinine concentration ratio (UA/UC) was measured every three months throughout the study. At 12 months, the geometric mean UA/UC was no different in diabetic children receiving dipyridamole, 0.60 mg/mmol, when compared with those receiving placebo, 0.87 mg/mmol. Glomerular filtration rate, urinary excretion of retinol binding protein, and N-acetyl-beta-D-glucosaminidase (NAG), blood pressure, and spontaneous platelet aggregation in response to stirring whole blood did not differ between the two groups at 12 months. Subgroup analysis to include only those children with high UA/UC before entry into the study also failed to show an effect of the drug on UA/UC. Eleven children had either persistently high UA/UC (n = 8: four on dipyridamole, four on placebo) or progression to high UA/UC (n = 3: two on dipyridamole, one on placebo). These children had significantly higher urinary excretion of retinol binding protein and NAG, bigger kidneys, and higher diastolic blood pressure both before and after treatment than the remaining 42 children, whereas there was no difference in spontaneous platelet aggregation between the two groups. These observations on the associations between UA/UC and other parameters of renal function suggest that measurement of 'tubular' proteins and diastolic blood pressure as well as UA/UC may contribute to the identification of those at risk of developing nephropathy.

Notizen: Cyclophanes, XXXIV [1]

Abstract: The title compound 3 was prepared by pyrolysis of the corresponding bis-sulfone 2 and subjected to X-ray structural analysis; space group P 1̅, a = 477.0(1), b = 625.6(2), c = 1363.6(3) pm, α = 82.79(2), β = 83.43(2), γ = 78.18(3)°, Ζ = 1, R = 0.058 for 900 reflections. The molecule contains a crystallographic symmetry centre, thus confirming the anti configuration.

Reactivity and Structure of Difluorophosphine Compounds and Their Platinum Complexes

Abstract: Various novel organodifluorophosphines involving aromatic and aliphatic substituents were prepared and used as ligands in reactions with (COD)PtCl2 or K2PtCl4; complexes of the type cis-dichlorobis(organodifluorophos-phine)platinum(II) or tetrakis (organodifluorophosphine)platinum(O) were formed. The 31P-n.m.r. data of these compounds were correlated with Pt-P bond lengths found from X-ray diffraction studies. The hydrolysis of RPF2 and Pt(RPF2)4 with water leads to the formation of RP(F)(O)(H) or [RP(F)(OH)]2[RP((F)]2Pt. Both products were characterized by n.m.r. spectra and by X-ray structure determinations.