Showing papers by "George M. Sheldrick published in 1984"

Synthesis and reactivity of bimetallic Au–Ag polyfluorophenyl complexes; crystal and molecular structures of [{AuAg(C6F5)2(SC4H8)}n] and [{AuAg(C6F5)2(C6H6)}n]

Abstract: The reaction of [NBun4][AuR2](R = C6F5 or C6F3H2-2,4,6) with Ag[ClO4] leads to complexes [{AuAgR2}n], which react with neutral ligands to give complexes [{AuAgR2L}n](L = neutral O-, N-, S- or P-donor ligand, alkene, or alkyne). For R = C6F5 and L = diphenylacetylene, the product is [{AuAgR2·0.5L}n]; the 0.5L can be displaced by other ligands, such as acetone, arenes, or alkenes, to reform [{AuAgR2L}n]. An X-ray diffraction study of [{AuAgR2L}n](R = C6F5, L = tetrahydrothiophene) reveals (AuAg)2 rings with Au–Ag 2.726 and 2.718 A(the first reported Au–Ag bond lengths), linked by Au ⋯ Au short contacts (2.889 A) to form infinite metal-atom chains. This complex crystallizes in space group Pccn, with a= 11.185(3), b= 22.475(6), c= 14.802(4)A, Z= 8, R= 0.041 for 2 005 reflections. The complex [{AuAgR2L}n](R = C6F5, L = benzene) crystallizes in space group C2/c, with a= 24.231(5), b= 7.570(1), c= 22.613(5)A, β= 117.49(2)°, Z= 8, and R= 0.035 for 3 008 reflections; it shows the same type of metal-atom chain (Au ⋯ Au 3.013; Au–Ag 2.702 and 2.792 A). The benzene ring is co-ordinated by one edge to silver. In both structures the gold atoms lie on a crystallographic two-fold axis.

Stufenweise Synthese ketten- und ringförmiger Siloxane — Kristallstrukturen

Abstract: Disilanole des Typs R2Si(OH)2 (1, 2: R = CHMe2, CMe3) und das Fluorsilanol (Me3C)2Si(OH)F (3) dienen in Reaktionen mit Halogensilanen als Startmaterial zum stufenweisen Aufbau von kettenformigen Siloxanen (4 – 15, 16 –20). Auch Siloxane mit voluminosen tert-Butyl- oder Silylaminogruppen sind leicht zuganglich (10, 16, 17, 20). Kristalline Silandiole (2, 14, 19) sind uber Wasserstoff-Bruckenbindungen ketten- (19) oder dimer-ringformig (2, 14) verknupft. Aus der Reaktion von F2Si(CHMe2)2 mit Kaliumhydroxid wurde das 1,3-Difluor- (18), 1,3-Dihydroxy (19), 1-Fluor-3-hydroxydisiloxan 6 sowie da Cyclotrisiloxan 21 isoliert. Die Si — O-Sechsringe 21 – 24 konnen gezielt aus den 1,3-Dihydroxydisiloxanen 19, 20 mit Di- und Trihalogensilanen erhalten werden. Die Kristallstrukturen von 2, 14 und 24 werden diskutiert. Stepwise Synthesis of Chain and Ring Siloxanes — Crystal Structures Disilanols of the type R2Si(OH)2 (1, 2: R = CHMe2, CMe3) and the fluorosilanol (Me3 C)2Si(OH)F (3) serve as starting materials in the reaction with halosilanes for the stepwise construction of chain siloxanes (4 – 15, 16 – 20). Even siloxanes with bulky tert-butyl or silylamino groups are easily prepared (10, 16, 17, 20). Crystalline silanediols (2, 14, 19) are connected in chains (19) or dimeric rings (2, 14) by hydrogen bonding. The 1,3-difluoro- (18), 1,3-dihydroxy- (19), and 1-fluoro-3-hydroxydisiloxane 6 as well as the cyclotrisiloxane 21 were isolated from the reaction of F2Si(CHMe2)2 with potassium hydroxide. Directed synthesis of Si — O six-membered rings (21 – 24) is possible via reaction of 1,3-dihydroxydisiloxanes 19, 20 with di- and trihalosilanes. The crystal structures of 2, 14, and 24 are discussed.

Die Pyridinaddukte der Goldhalogenide. 3. Darstellung, Eigenschaften und Kristallstruktur zweier Modifikationen von AuBr · NC5H5

Abstract: Bei der Umsetzung von AuBr · S(CH2C6H5)2 mit Pyridin in absolutem Ethanol kristallisiert AuBr · Pyridin in Form trikliner Kristalle mit der Raumgruppe P1 und den Gitterkonstanten a = 791,5(2) pm, b = 935,6(2) pm, c = 1005,1(3) pm, α = 85,78(2)°, β = 102,07(2)°, γ = 109,31(2)°. Wird die Reaktion dagegen in absolutem Toluol durchgefuhrt, so erhalt man eine monokline Modifikation mit der Raumgruppe C2/c und a = 1225,9(2) pm, b = 1522,2(3) pm, c = 1459,7(3) pm, s = 97,82(2)°. Die Strukturen beider Modifikationen bestehen aus linearen Au(py)2- und AuBr2-Gruppen, die durch schwache Gold-Gold-Wechselwirkungen zu kettenformigen Komplexen verbunden sind. Die trikline Modifikation bildet diskrete Au4-Zickzack-Ketten AuBr2—Au(py)2—Au(py)2—AuBr2. In der monoklinen Phase sind die Baugruppen in der Abfolge AuBr2—Au(py)2 zu unendlichen Ketten verknupft. Pyridine Adducts of Gold Halides. 3. Preparation, Properties, and Crystal Structure of Two Modifications of AuBr · NC5H5 The reaction of AuBr · S(CH2C6H5)2 with pyridine in absolute ethanol yields the crystalline compound AuBr · pyridine. It crystallizes in the triclinic space group P1 with the lattice constants a = 791.5(2) pm, b = 935.6(2) pm, c = 1005.1(3) pm, α = 85.78(2)°, β = 102.07(2)°, γ = 109.31(2)°. When the solvent is toluene, monoclinic crystals are formed with the space group C2/c and a = 1225.9(2) pm, b = 1522.2(3) pm, c = 1459.7(3) pm, β = 97.82(2)°. The triclinic structure is built up by Au4 zig-zag chains AuBr2—Au(py)2—Au(py)2—AuBr2, whereas the monoclinic phase contains infinite chains with the sequence AuBr2—Au(py)2. In each case the linkage is formed by weak Au—Au-interactions.

Synthesis of polynuclear complexes containing the tridentate bis(diphenylphosphino)methanide ligand. Crystal structures of the compounds [(C6F5)2Au(Ph2PCHPPh2)Au(C6F5)] and [(C6F5)2Au(Ph2PCHPPh2)Au(Ph2PCHPPh2)Au(C6F5)2]ClO4

Abstract: Reaction of NaH with [Au(C6F5)2(Ph2PCH2PPh2)]ClO4 causes both deprotonation of the methylene group and elimination of the anion and leads to the neutral bis(diphenylphosphino)methanide complex [Au(C6F5)2(Ph2PCHPPh2)], which further reacts with gold(I) or silver(I) derivatives to give bi- or tri-nuclear complexes The structures of a binuclear and a trinuclear gold derivative have been confirmed by X-ray crystallography Crystals of [(C6F5)2Au(Ph2P[graphic omitted]u(C6F5)] are monoclinic, space group P21/m, with a= 10003(2), b= 17389(4), c= 11754(3)A, β= 10353(2)°, and Z= 2; R= 0034 for 4 016 reflections Crystals of [(C6F5)2Au(Ph2P[graphic omitted]HPPh2)Au(C6F5)2]ClO4(CHCl3 solvate) are monoclinic, space group P21/m, with a= 17456(6), b= 17704(6), c= 17749(8)A, β= 9286(5)°, and Z= 2; R= 0096 for 5 230 reflections

Funktionelle Siloxane und Cyclotetrasiloxane – Kristallstruktur eines Cycloboratrisiloxans

Abstract: Lithiumsalze des Di-tert-butylfluorsilanols und -silandiols reagieren mit Fluorsilanen zu fluorfunktionellen 1,3-Di- (1, 2), 1,3,5-Tri- (3, 4) und 1,3,5,7,9-Pentasiloxanen (5) Der Einsatz des Dilithiumsalzes des Silandiols fuhrt in der Reaktion mit SiF4 und CH3SiF3 zur Bildung fluorfunktioneller Cyclo-1,3,5,7-tetrasiloxane (6, 7) Das Cyclotetrasiloxan 8 wird durch thermische LiF-Abspaltung aus 1,1-Difluor-1,3-disiloxan-3-ol (2) erhalten Die achtgliedrigen Ring-systeme 9 und 10 entstehen in der Reaktion des dilithiierten 1,3,5-Trisiloxan-1,5-diols mit SiF4 (9) und BF3 (10) Die Kristallstruktur des Cyclo-1-bora-3,5,7-trisiloxans 10 wird vorgestellt und diskutiert Functional Siloxanes and Cyclotetrasiloxanes – Molecular Structure of a Cycloboratrisiloxane Lithium salts of di-tert-butyl-fluorosilanol and -silandiol react with fluorosilanes to give 1,3-di- (1, 2), 1,3,5-tri- (3, 4), and 1,3,5,7,9-pentasiloxanes (5) Reactions of the dilithium salt of the silandiol with SiF4 and CH3SiF3 lead to the formation of fluorofunctional cyclo-1,3,5,7-tetrasiloxanes (6, 7) The cyclotetra-siloxane 8 is obtained by thermal LiF elimination from 1,1-difluoro-1,3-disiloxane-3-ol (2) The eight-membered ring systems 9 and 10 are formed in the reaction of dilithiated 1,3,5-trisiloxane-1,5-diol with SiF4 (9) and BF3 (10) The crystal structure of the cyclo-1-bora-3,5,7-trisiloxane 10 is reported and discussed

Crystal structure and catalytic properties of a platinum–iridium mixed cluster, [Pt2Ir2(µ-CO)3(CO)4(PPh3)3]

Abstract: The compound [Pt2Ir2(CO)7(PPh3)3] has been synthesised from [Pt12(CO)24]2– and [Ir(CO)Cl(PPh3)2]. A single-crystal X-ray structure determination (space group P, Z= 2, R= 0.050 for 5 402 reflections) has shown that the metal atoms adopt a ‘butterfly’ configuration with the iridium and platinum atoms occupying ‘hinge’ and ‘wing-tip’ positions respectively. The mixed-metal cluster is an active catalyst for hydrogenation of olefins.

Preparation and crystal structure of trichloro(thionitrosyl)bis(triphenylphosphine)osmium, [Os(NS)Cl3(PPh3)2]

Abstract: The compound (NSCl)3 reacts with [MCl2(PPh3)3](M = Os or Ru) in tetrahydrofuran to give the thionitrosyl complexes [M(NS)Cl3(PPh3)2][M = Os (1) or Ru (2)]. Nitrosyl chloride or bromide converts (1) to the corresponding nitrosyl complex. Crystals of (1) are monoclinic, space group I2/a, with a= 1 615.9(6), b= 943.7(5), c= 2 250.6(10) pm, β= 103.02(3)°, and Z= 4. The structure was refined to R= 0.042 for 2 076 diffractometer data. The osmium is octahedrally co-ordinated with the phosphines cis to the NS group; a crystallographic two-fold axis along the Cl–Os–N–S bonds imposes linearity at nitrogen, with Os–N 177.9(9), N–S 150.3(10), Os–P 245.9(2), Os–Cl(cis) 238.7(3), and Os–Cl(trans) 239.9(3) pm. Complex (2) is apparently isostructural, with a= 1 613.5(15), b= 941.8(4), c= 2 249.3(15) pm, and β= 102.94(3)°.

Synthesis and X-ray structure of [Ag2(Ph2X2)4][AsF6]2(X = S or Se); six-membered silver–sulphur and silver–selenium rings

Abstract: The reaction of diphenyl disulphide with AgAsF6 in liquid SO2 leads to [Ag2(Ph2S2)4][AsF6]2- The X-ray structure [space group P, a= 10.902(4), b= 10.976(6), c= 13.308(7)A, α= 112.82(4), β= 92.43(3), γ= 107.69(3)°, Z= 1, and R= 0.041 for 5 139 unique observed reflections] shows a centrosymmetric six-membered ring, in which two silver atoms are connected by two bridging Ph2S2 ligands; further unidentate sulphur ligands complete irregular three-co-ordination at silver. The analogous reaction with diphenyl diselenide leads to the isostructural [Ag2(Ph2Se2)4][AsF6]2[space group P, a= 10.676(3), b= 11.253(3), c= 13.625(4)A, α= 66.40(2), β= 89.67(2), γ= 71.40(2)°, Z= 1, and R= 0.044 for 4 439 reflections].

Preparation and crystal structure of nonacarbonyl-di-µ-hydrido-µ3-phenylimido-triangulo-triruthenium, [Ru3(µ-H)2(CO)9(µ3-NPh)]

Abstract: [Ru3(CO)10(NPh)](1) reacts with molecular hydrogen to give [Ru3H2(CO)9(NPh)](2), which can be carbonylated to produce [Ru3(CO)12]. A single-crystal X-ray structure determination of (2) confirms the presence of a triply-bridging NPh group and two doubly-bridging hydrogen atoms: space group P21/c, a= 11.697(2), b= 9.265(2), c= 18.589(4)A, β= 100.18(2)°, Z= 4, R= 0.039 for 3 019 unique observed reflections. Mean bond lengths include Ru–Ru 2.805(1)(H-bridged), 2.680(1)(unbridged), Ru–N 2.068(6), Ru–H 1.76(5)A.

Crystal and molecular structure of the DNA-binding antitumour antibiotic triostin A

Abstract: Crystals of the polar conformer of the quinoxaline antibiotic triostin A are orthorhombic, space group P212121, with a= 20.940(5), b= 18.528(4), and c= 18.795(4)A. There are two molecules of isoamyl acetate solvent per triostin A molecule. The cyclic octadepsipeptide has approximate two-fold symmetry. The quinoxaline chromophores and the disulphide cross-bridge project from opposite sides of the peptide ring. The conformation is compared with that found for the synthetic analogue TANDEM, and with the results of n.m.r. investigation. The observed structure accounts for the higher binding constants of the natural antibiotic, as well as its capacity to bind at GC-rich sequences in DNAs.

Polyspirane, 7. Umlagerungskaskaden, 2: Von Polyspiranen zu Polycyclen – Sechsfache 1,2‐Verschiebungen an funktionalisierten Pentaspiro[2.0.2.0.2.0.2.0.2.1]hexadecanen

Abstract: Die Pentaspirohexadecane 3a, b konnen uber 7a, b in 8a, b umgelagert werden. 7a, b sind potentielle Vorlaufer des [6.4]Coronans 1. 7a und 8a wurden zu 7d bzw. 8e benzoyliert, die Molekulstrukturen von 7d und 8e rontgenographisch bestimmt. 7a, b und 8a, b sind all-cis-konfiguriert, 7a und 7b enthalten die Hydroxylgruppe axial gebunden. Die Gesamtumlagerungen von 3a, b konnen demnach als sechsfache 1,2-Verschiebungen unter Inversion am jeweiligen Ausgangs- und Endpunkt der Umlagerung beschrieben werden. Polyspiranes, 7. Cascade Rearrangements, 2: From Polyspiranes to Polycycles – Sixfold 1,2-Shifts in Functionalized Pentaspiro[2.0.2.0.2.0.2.0.2.1]hexadecanes The pentaspirohexadecanes 3a, b may be rearranged to 8a, b via 7a, b, which are potential precursors of the [6.4]coronane 1. 7a and 8a were benzoylated to give 7d and 8e, respectively, the molecular structures of which were determined by X-ray analysis. 7a, b and 8a, b adopt the all-cis-configuration. 7a and 7b contain axial hydroxyl groups. The overall rearrangements of 3a, b may thus be described in terms of sixfold 1,2-shifts with inversion at both the migration origins and termini.

(Disilylamino)phosphane (Rf)2P – N(SiMe3)2 – Bausteine für PN3S2‐Ringe

Abstract: Aus den (Disilylamino)phosphanen (Rf)2P – N(SiMe3)2 (Rf CF3, C2F5) und S3N2Cl2 werden unter Abspaltung von Me3SiCl und S8 neue Cyclophosphadithiatriazene der Zusammensetzung (Rf)2PN3S2 (1a, b) erhalten. Als Nebenprodukte treten Phosphanimide (Rf)2P(Cl) NSiMe3 (2a, b) auf. 1a, b bilden mit Norbornadien 1:1-Addukte 3a, b. Die Rontgenstrukturanalyse von 3a (Rf CF3) wird mitgeteilt. Aus 1a bildet sich nach mehrtagigem Stehenlassen eine kristalline Verbindung [(CF3)2PN2S]2 (4), deren Rontgenstrukturbestimmung einen achtgliedrigen Ring mit 1,3-P(CF3)2-Gruppen zeigt. (Disilylamino)phosphanes (Rf)2P – N(SiMe3)2 – Precursors for PN3S2 Rings The reactions of the (disilylamino)phosphanes (Rf)2P – N(SiMe3)2 (Rf CF3, C2F5) with S3N2Cl2 lead to new cyclophosphadithiatriazenes of composition (Rf)2PN3S2 (1a, b) with elimination of Me3SiCl and S8. By-products are (Rf)2P(Cl) NSiMe3 (2a, b). Reaction of 1a, b with norbornadiene yields 1:1 adducts 3a, b. The X-ray structure analysis of 3a (Rf CF3) is reported. When 1a is allowed to stand for several days a crystalline compound of composition [(CF3)2PN2S]2 (4) is formed. The X-ray structure analysis shows that 4 contains an eight-membered ring with 1,3-P(CF3)2 groups.

Preparation and crystal structures of two phosphorus–sulphur rings: (PhP)3S3 and (PhP)2S4

Abstract: The 1 : 1 reaction between PPhCl2 and (SnMe3)2S in CS2 provides a convenient direct route to (PhP)3S3(1), which reacts with elemental sulphur to give (PhP)2S4(2). Both structures have been determined by X-ray diffraction using twinned crystals. Compound (1) is monoclinic, space group P21, with a= 8.884(2), b= 13.713(2), c= 8.309(2)A, β= 106.61 (2)°, Z= 2, and R= 0.051 for 1 938 unique observed reflections. The structure contains an unsymmetrical five-membered ring with one exocyclic sulphur, and does not agree with a previous proposal based on n.m.r. data. Compound (2) is monoclinic, space group P21/c, with a= 6.624(1), b= 14.438(3), c= 7.667(2)A, β= 95.31(2)°, Z= 2, and R= 0.060 for 880 unique observed reflections. The four-membered ring with two trans exocyclic sulphurs possesses a crystallographic centre of symmetry.

Reactions of cis-di-isocyanidebis(perfluorophenyl)gold(III) complexes with hydrazines. Crystal and molecular structure of cis-[Au{C(NHC6H4Me-p)=N–N(Ph)C(NHC6H4Me-p)}(C6F5)2]

Abstract: Addition of CNR (R = Ph or p-tolyl) to solutions of cis-[Au(C6F5)2(OEt2)2]ClO4 leads to cis-[Au(C6F5)2(CNR)2ClO4, which reacts (a) with NHPhNHPh to give the cationic complexes [A[graphic omitted](NHR)}(C6F5)2]ClO4, which readily undergo deprotonation to form [A[graphic omitted](NHR)}(C6F5)2], and (b) with NH2NHR′(R′= H or Ph) to give [A[graphic omitted](NHR)}(C6F5)2]. The structure of [A[graphic omitted]-(NHC6H4Me-p)}(C6F5)2] has been determined by X-ray diffraction [space group P21/c, with a= 12.230(2), b= 20.276(3), c= 13.123(2)A, β= 101.21(2)°, R= 0.036 for 5 822 reflections].

Preparation and crystal structures of two phosphorus–sulphur rings: (RPS)4 and (RPS2)2(R = C6H2Me3-2,4,6)

Abstract: The 1:1 reaction between PRCl2(R = C6H2Me3-2,4,6) and (Me3Si)2S in toluene yields (RPS)4(1) which slowly disproportionates under mild conditions (35–40 °C, 3 d) to (RPS2)2(2). Both structures have been determined by X-ray diffraction. Compound (1) is monoclinic, space group Cc, with a= 2 299.3(7), b= 1 167.9(3), c= 1 937.8(6) pm, β= 130.65(2)°, and Z= 4; R= 0.050 for 3 209 unique observed reflections. The eight-membered (PS)4 ring adopts the crown conformation but is disordered. Compound (2) is monoclinic, space group P21/c, with a= 890.1 (2), b= 1 845.2(12), c= 641.3(1) pm, β= 98.74(1)°, and Z= 2; R= 0.062 for 904 unique observed reflections. The four-membered ring with two trans exocyclic sulphurs possesses a crystallographic centre of symmetry.

Polyspirane, 91). Umlagerungskaskaden, 41). Über die Verwendbarkeit von Polyspiranen zum Eintritt in Polycyclen‐Hyperflächen – Fünf‐ bzw. neunfache 1,2‐Verschiebungen an einem Pentaspiro[3.0.2.0.3.0.2.0.3.1]nonadecan

Abstract: Sauer katalysierte Umlagerungen des Pentaspirans 7b liefern in Abhangigkeit von den Reaktionsbedingungen das Propellan 13 oder den Hexacyclus 14. Struktur und Konformation von 13 und 14 wurden uber Kristallstrukturanalysen ihrer Derivate 22 bzw. 16 und 18 bestimmt. Die Umlagerungen 7b13 und 7b14 verlaufen diastereospezifisch und konnen als funf- bzw. neunfache 1,2-Verschiebungen aufgefast werden. Polyspiranes, 91). Cascade Rearrangements, 41). On the Usefulness of Polyspiranes for Entering Energy Surfaces of Polycyclic System – Five- and Ninefold 1,2-Shifts in a Pentaspiro[3.0.2.0.3.0.2.0.3.1]nonadecane Acid-catalyzed rearrangements of the pentaspirane 7b yield either the propellane 13 or the hexacyclic compound 14, depending on the reaction conditions. The structures and conformations of 13 and 14 were determined by crystal structure analyses of their derivatives 22 and 16 and 18, respectively. The rearrangements 7b13 and 7b14 proceed diastereospecifically and are rationalized as five- and ninefold 1,2-shifts, respectively.

Crystal Structure of 2-Thiopyrrole-1,2-dicarboximide-(bis-triphenylphosphine)copper(I)chloride, [(Ph3P)2Cu(Cl)C6H4N2OS]

Abstract: Cristallisation dans le systeme monoclinique, groupe C2/c et affinement de la structure jusqu'a R=0,063. Coordination tetraedrique autour des atomes Cu