Low-temperature specific heat of the cluster compound Au55 (P(C6H5)3)12Cl6

Specific-heat measurements on the cluster compound Au₅₅(P(C₆H₅)₃)₁₂Cl₆ at temperatures 0.06 K ≤T≤3 K and in magnetic fields 0≤B≤6 T are reported. While above 0.6 K the specific heatC is dominated by the inter-cluster vibrational contribution observed previously, an anomalous increase ofC towards lowT is observed below 0.3 K, withC ～T ^?2. This contribution develops into a Schottky-like anomaly forB≥0.4 T, indicating that it might be attributed to local moments which are also observed in ESR measurements. From the height of the anomaly one can infer that approximately one tenth of the Au₅₅ clusters carry a magnetic moment. For 0.6 K≤T≤1 K andB=0 our data indicate the absence of a linear electronic specific-heat contribution expected for bulk Au. This possibly constitutes the first direct observation of the quantum-size effect on electronic energy levels in the specific heat.     

Study of (π-C5H5)2Ti(CH3)Cl and (π-C5H5)2Ti(C6H5)Cl in soluble Ziegler catalysts

Soluble ethylene polymerization catalysts derived from (π-C₅H₅)₂Ti(R)Cl and R ′AlCl₂, where R = methyl or phenyl and R ′ = methyl or ethyl, were studied both by polymerization kinetics at 0°C and by diagnostic experiments. It was found that the first insertion of ethylene into the Ti? R bond is difficult when R = methyl or phenyl, and for this reason these catalysts show a different overall behavior than when R = ethyl or higher alkyl.     

Über die Kristallstruktur von (C6H5)3SiSH und (C6H5)3SiSBr und die Darstellung des Iodsulfans (C6H5)3SiSI

The Crystal Structure of (C₆H₅)₃SiSH and (C₆H₅)₃SiSBr and the Preparation of the Iodosulfane (C₆H₅)₃SiSI The preparation of the halogenosulfanes Ph₃SiSBr and Ph₃SiSI from Ph₃SiSH and N-halogenosuccinimide is reported. They are characterized by vibrational spectroscopic measurements. Ph₃SiSBr crystallizes in space group P1 with a = 899.3(8) pm, b = 941.3(7) pm, c = 1 051.4(7) pm, α = 109.88(5)°, β = 99.23(6)°, γ = 96.78(6)° and Z = 2. Ph₃SiSH crystallizes in space group P2₁/c with a = 1 879.4(8), b = 966.3(5), c = 1 845.2(9), β = 107.84(4), Z = 8. The halogenosulfanes decompose in polar solvents by formation of sulphur and triphenylsilanhalide.     

Synthesis and structure of anilinium chloranilate (NH3C6H5)2 · (C6O4C12) and acid ammonium chloranilate dihydrate NH4H5O2(C6O4Cl2)

Conclusions The authors have synthesized anilinium chloranilate (NH₃C₆H₅)₂(C₆O₄Cl₂) (I) and acid ammonium chloranilate dihydrate NH₄H₅O₂(C₆O₄C1₂) (II). By x-ray structural analysis they have established their crystal structures. In crystals of NH₄H₅O₂(C₆O₄Cl₂) they find the ion H₅O ₂ ⁺ with the unusual O-H-O bond length of 2.81 A. The anions of chloranilic acid in crystals (I) and (II) have equal charges but different structures.Translated from IzvestiyaAkademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 487–489, March, 1981.     

Zur Polyreaktion von Äthylen mit dem löslichen Ziegler-Natta-Katalysator (C5H5)2Ti(C2H5)Cl/Al(C2H5)Cl2

Ohne Zusammenfassung     

Novel products from C6H5 + C6H6/C6H5 reactions

To date only one product, biphenyl, has been reported to be produced from C(6)H(5) + C(6)H(6)/C(6)H(5) reactions. In this study, we have investigated some unique products of C(6)H(5) + C(6)H(6)/C(6)H(5) reactions via both experimental observation and theoretical modeling. In the experimental study, gas-phase reaction products produced from the pyrolysis of selected aromatics and aromatic/acetylene mixtures were detected by an in situ technique, vacuum ultraviolet (VUV) single photon ionization (SPI) time-of-flight mass spectrometry (TOFMS). The mass spectra revealed a remarkable correlation in mass peaks at m/z = 154 {C(12)H(10) (biphenyl)} and m/z = 152 {C(12)H(8) (?)}. It also demonstrated an unexpected correlation among the HACA (hydrogen abstraction and acetylene addition) products at m/z = 78, 102, 128, 152, and 176. The analysis of formation routes of products suggested the contribution of some other isomers in addition to a well-known candidate, acenaphthylene, in the mass peak at m/z = 152 (C(12)H(8)). Considering the difficulties of identifying the contributing isomers from an observed mass number peak, quantum chemical calculations for the above-mentioned reactions were performed. As a result, cyclopenta[a]indene, as-indacene, s-indacene, biphenylene, acenaphthylene, and naphthalene appeared as novel products, produced from the possible channels of C(6)H(5) + C(6)H(6)/C(6)H(5) reactions rather than from their previously reported formation pathways. The most notable point is the production of acenaphthylene and naphthalene from C(6)H(5) + C(6)H(6)/C(6)H(5) reactions via the PAC (phenyl addition-cyclization) mechanism because, until now, both of them have been thought to be formed via the HACA routes. In this way, this study has paved the way for exploring alternative paths for other inefficient HACA routes using the PAC mechanism.