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Sunlight photolysis of decamethyltitanocene dihydrosulfide [Cp*2Ti(SH)2] (1, Cp* = η5-C5Me5) in toluene affords the titanium sulfide clusters [(Cp*Ti)6(μ3-S)8] (4) and [(Cp*Ti)4(μ3-S)3(μ2-S)3] (5), the former in very low yield and the latter in good yield. The crystal structures of both compounds are toluene solvates and are based on a nearly regular titanium octahedron for 4 and a trigonal pyramid for 5. The [(Cp*Ti)3(μ3-S)(μ2-S)3] (6) complex isolated in a trace amount from the photolysis of 1 in hexane could be a precursor of 4. A plausible mechanism for the formation of 5 and 6 follows a mechanism recently proposed for photolysis of [Cp*2Ti(OH)2] by U. Rosenthal et al.

The Oligo‐Miocene Most Basin is the largest preserved sedimentary basin within the Eger Graben, the easternmost part of the European Cenozoic Rift System (ECRIS). The basin is interpreted as a part of an incipient rift system that underwent two distinct phases of extension. The first phase, characterised by NNE–SSW‐ to N–S‐oriented horizontal extension between the end of Eocene and early Miocene, was oblique to the rift axis and caused evolution of a fault system characterised by en‐echelon‐arranged E–W (ENE–WSW) faults. These faults defined a number of small, shallow initial depocentres of very small subsidence rates that gradually merged during the growth and linkage of the normal fault segments. The youngest part of the basin fill indicates accelerated subsidence caused probably by the concentration of displacement at several major bounding faults. Major post‐depositional faulting and forced folding were related to a change in the extension vector to an orthogonal position with respect to the rift axis and overprinting of the E–W faults by an NE–SW normal fault system. The origin of the palaeostress field of the earlier, oblique, extensional phase remains controversial and can be attributed either to the effects of the Alpine lithospheric root or (perhaps more likely because of the dominant volcanism at the onset of Eger Graben formation) to doming due to thermal perturbation of the lithosphere. The later, orthogonal, extensional phase is explained by stretching along the crest of a growing regional‐scale anticlinal feature, which supports the recent hypothesis of lithospheric folding in the Alpine–Carpathian foreland.

The Early Miocene Bilina Palaeodelta consists of fluvio-deltaic and lacustrine clastics deposited along the south-eastern margin of the extensional Most Basin, part of the Eger Graben in north Bohemia (Czech Republic). The Bilina succession shows evidence of repeated advances of an axial deltaic system across a thick accumulation of organic material and clay in the hangingwall of an active fault. Exposures up to ca 4·5 km long in the Bilina open-cast mine help bridge the gap between seismic scale and typical outcrop scale of observation and thus allow the relationships between small-scale and basin-scale stratal geometries to be evaluated. The Bilina Palaeodelta deposits include sand-dominated, fluvial channel fills and heterolithic sheets interpreted as delta plain strata, sand-dominated mouth-bar wedges and heterolithic sheets of prodeltaic deposits, passing distally into lacustrine clays. The depositional environment is interpreted as a fluvial-dominated, mixed-load, lacustrine delta with a high degree of grain-size segregation at the feeder-channel mouths. On the largest temporal and spatial scales, variable tectonic subsidence controlled the overall advance and retreat of the delta system. The medium-term transgressive-regressive history was probably driven by episodes of increased subsidence rate. However, at this temporal scale, the architecture of the deltaic sequences (deltaic lobes and correlative lacustrine deposits) was strongly affected by: (i) compaction of underlying peat and clay which drove lateral offset stacking of medium-term sequences; and (ii) growth of a fault-propagation fold close to the active Bilina Fault. At the smallest scale, the geometries of individual mouth bars and groups of mouth bars (short-term sequences) reflect the interaction among sediment loading, compaction and growth faulting that produced high-frequency relative lake-level fluctuations and created local accommodation at the delta front.

The reduction of symmetric, fully-substituted titanocene dichlorides bearing two pendant ω-alkenyl groups, [TiCl2(η5-C5Me4R)2], RCH(Me)CH=CH2 (1 a), (CH2)2CH=CH2 (1 b) and (CH2)3CH=CH2 (1 c), by magnesium in tetrahydrofuran affords bis(cyclopentadienyl)titanacyclopentanes [TiIV{η1:η1:tlsb&endash;3%>η5:η5-C5Me4CH(Me)CH(Ti)CH2CH(CH2(Ti))CH(Me)C5Me4}] (2 a), [TiIV{η1:η1:η5:η5-C5Me4(CH2)2CH(Ti)(CH2)2CH(Ti)(CH2)2C5Me4}] (2 b) and [TiIV{η1:η1:η5:η5-C5Me4(CH2)2CH(Ti)CH(Me)CH(Me)CH(Ti)(CH2)2C5Me4}] (2 c), respectively, as the products of oxidative coupling of the double bonds across a titanocene intermediate. For the case of complex 1 c, a product of a double bond isomerisation is obtained owing to a preferred formation of five-membered titanacycles. The reaction of the titanacyclopentanes with PbCl2 recovers starting materials 1 a from 2 a and 1 b from 2 b, but complex 2 c affords, under the same conditions, an isomer of 1 c with a shifted carbon-carbon double bond, [TiCl2{η5-C5Me4(CH2CH2CH=CHMe)}2] (1 c′). The titanacycles 2 a-c can be opened by HCl to give ansa-titanocene dichlorides ansa-[{η5:η5-C5Me4CH(Me)CH2CH2CH(Me)CH(Me)C5Me4}TiCl2] (3 a), ansa-[{η5:η5-C5Me4(CH2)8C5Me4}TiCl2] (3 b), along with a minor product ansa-[{η5:η5-C5Me4CH2CH=CH(CH2)5C5Me4}TiCl2] (3 b′), and ansa-[{η5:η5-C5Me4(CH2)3CH(Me)CH(Me)CH=CHCH2C5Me4}TiCl2] (3 c), respectively, with the bridging aliphatic chain consisting of five (3 a) and eight (3 b, 3 b′ and 3 c) carbon atoms. The course of the acidolysis changes with the nature of the pendant group; while the cyclopentadienyl ring-linking carbon chains in 3 a and 3 b are fully saturated, compounds 3 c and 3 b′ contain one asymetrically placed carbon-carbon double bond, which evidently arises from the β-hydrogen elimination that follows the HCl addition.

The complex CPh(CPh)4CPhTiBr2 has been obtained by reaction of the system C6Me6 − (C6H6)Ti(AlBr4)2 − 2Et3Al with diphenylacetylene. The titanacycloheptatriene ring is not planar, all CC bonds are roughly equivalent and all carbon atoms are at bonding distances to titanium. The complex is a product of catalyst deactivation in which the oxidative addition of trimeric intermediate to tiII results in a release of aluminium-containing ligands.

The (C 2 H 5 ) 2 AlCl/TiCl 4 catalyst induces the [4+2] cycloaddition of butadiene or the [6+2] cycloaddition of 1,3,5-cycloheptatriene (CHT) to individual acetylenic moieties of 1,4-bis(trimethylsilyl)buta-1,3-diyne (BSD). Heating of the 2:1 butadiene adduct, bis(2-trimethylsilylcyclohexa-1,4-dien-1-yl), to 250 °C yields 2,2'-bis(trimethylsilyl)biphenyl. The 1:1 adduct of BSD with CHT, 7-trimethylsilyl-8-trimethylsilylethynylbicyclo[4.2.1]nona-2,4-diene, is obtained as virtually the only product if the initial molar ratio CHT : BD equal to 1.86 is used.

The catalytic system Et 2 AlCl/TiCl 4 induces Diels-Alder addition of phenyl(trimethylsilyl)acetylene (PTMSA) to 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, and [6+21 addition of PTMSA to 1,3,5-cycloheptatriene. The 1-phenyl-2-(trimethylsilyl)-cyclohexa-1,4-dienes obtained undergo thermolysis, yielding the corresponding ortho -(trimethylsilyl)biphenyl derivatives. The cyclohexadienes containing vicinal methyl and trimethylsilyl groups evolve methane at 300°C (the 3-methyl group is released). All other derivatives release hydrogen at only 260°C.

By treating Ti(η6-toluene)[(μ-X)2(AlX2)]2 (X = Cl: 1a, X = Br 1b) with C2R2 (R = Me, Ph) tetraorganylcyclobutadiene complexes of formula Ti(η4-C4R4)[(μ-X)2(AlX2)]2 (R = Ph, X = Cl: 2a, X = Br: 2b; R = Me, X = Br: 3b) have been obtained in good yields. Compound 2b has been studied by X-ray diffraction methods. The titanium atom possesses an approximate square pyramidal coordination, the apical position being occupied by the symmetrically bonded tetraphenylcyclobutadiene ring, the four bridging bromides to the two AlBr2 groups forming the base of the pyramid, 0.99 A away from the titanium atom. The tetrabromoaluminato moiety of 2b can be substituted by carbocyclic anionic ligands, such as Cp and COT, and the corresponding complexes 4 and Ti(η4-C4Ph4)(COT) were obtained. The spectroscopic study of the Ti(η6-benzene)[(μ-X)2(AlX2)]2/diphenylacetylene (DPA) system (X = Cl: 5a, X = Br: 5b) has revealed the existence of three products, corresponding to the 1:1, 1:2, and 1:3 molar ratios. The possible role of the known AlX3 · C4R4 complexes in this reaction is discussed. The cyclotrimerization reactions of substituted acetylenes in the presence of η6-arenetitanium(II) complexes as precursors have been studied. In toluene or methylcyclohexane Ti(η6-toluene)[(μ-Br)2(AlBr2)]2 was found to catalyze the formation of alkyl-substituted aromatic hydrocarbons from 2-butyne, phenylacetylene, and 1-hexyne at about 80°C over 15 h with turnovers (moles of converted alkyne per mole of titanium) of about 520, 900, and 990, respectively. The cyclooligomerization of DPA in the presence of Ti(η6-benzene)[(μ-X)2(AlX2)]2 (X = Cl, Br) was studied in detail. The activity of the chloro derivative 5a is higher than that of the bromide catalytic precursor 5b. In addition to hexaphenylbenzene and octaphenylcyclooctatetraene, other oligomerization by-products (triphenylethylene, 1,1,2,2-tetraphenylethane, 1,2,3-triphenylnaphthalene, and 1,2,3-triphenylazulene) were observed, whose formation was drastically reduced in the presence of alkyl aluminium halides. Reaktivitat von Titan(II)-Aren-Derivaten mit substituierten Alkinen. Cyclooligomerisations-Reaktionen und Kristall- und Molekulstruktur von [η4-C4(C6H5)4]Ti[(μ-Br)2(AlBr2)]2 Durch Umsetzung von Ti(η6-toluene)[(μ-X)2(AlX2)]2 (X = Cl: 1a, X = Br 1b) with C2R2 (R = Me, Ph) wurden Tetraorganylcyclobutadien-Komplexe der Zusammensetzung Ti(η4-C4R4)[(μ-X)2(AlX2)]2 (R = Ph, X = Cl: 2a, X = Br: 2b; R = Me, X = Br: 3b) in guten Ausbeuten erhalten. Verbindung 2b wurde mit Rontgenbeugungsmethoden untersucht. Das Titan-Atom ist naherungsweise quadratisch-pyramidal koordiniert, wobei die apikale Position von dem symmetrisch gebundenen Tetraphenylcyclobutadien-Ring eingenommen wird und die vier zu den AlBr2-Gruppen verbruckenden Brom-Atome die 0.99 A vom Titan-Atom entfernte Basisflache der Pyramide bilden. Die Tetrabromoaluminat-Gruppe in 2b kann durch carbocyclische anionische Liganden wie Cp und COT ersetzt werden, wobei die entsprechenden Komplexe 4 und Ti(η4-C4Ph4)(COT) erhalten wurden. Die spektroskopische Untersuchung des Systems Ti(η6-benzol)-[(μ-X)2(AlX2)]2/diphenylacetylen (DPA) (X = Cl: 5a, X = Br: 5b) erbrachte den Nachweis dreier den molaren Verhaltnissen von 1:1, 1:2 und 1:3 entsprechender Produkte. Die mogliche Rolle des AlX3 · C4R4-Komplexes in dieser Reaktion wird diskutiert. Die Cyclotrimerisierungsreaktionen von substituiertem Acetylen in Gegenwart von η6-Aren-Titan(II)-Komplexen als Vorstufen wurden untersucht. Es zeigte sich, das Ti(η6-toluol)[(μ-Br)2(AlBr2)]2 in Toluol oder Methylcyclohexan bei ca. 80°C im Verlaufe von 15 h die Bildung von Alkyl-substituierten aromatischen Kohlenwasserstoffen aus 2-Butin, Phenylacetylen und 1-Hexin mit einem Umsatz (mol abreagierendes Alkin pro mol Titan) von 600, 900 bzw. 990 katalysiert. Die Cyclooligomerisierung von DPA in Gegenwart von Ti(η6-benzol)[(μ-X)2(AlX2)]2 (X = Cl, Br) wurde ausfuhrlich untersucht. Die Aktivitat des Chloro-Derivats 5a ubersteigt die der Bromo-Katalysator-Vorstufe 5b. Auser Hexaphenylbenzol und Octaphenylcyclooctatetraen wurden weitere Nebenprodukte der Oligomerisierung beobachtet (Triphenylethen, 1,1,2,2-tetraphenylethan, 1,2,3-Triphenylnaphthalin und 1,2,3-Triphenylazulen), deren Bildung in Gegenwart von Alkylaluminiumhalogeniden deutlich verringert war.

The action of aluminium halides upon polystyrene was studied as a function of the nature of the reaction medium and of the concentration of catalyst. It was demonstrated that polystyrene undergoes crosslinking, the extent of which is particularly important in chlorinated aliphatic solvents and at high catalyst concentrations. In additions, phenyl rings of the polymer are alkylated and halogenated by the solvent or catalyst. Infrared spectroscopic investigation of the structure of the products indicated that in most cases crosslinking was connected with the formation of 1,4-disubstituted, and eventually 1,2,4-trisubstituted benzenes. In carbon tetrachloride medium, meta substitution was also detected. In products obtained when polystyrene was treated with high amounts of the Lewis acid in CCl4 medium degrees of substitution even higher than three were probable.

The polymerization of isoprene with C2H5AlCl2 to yield solid cyclopolyisoprene is markedly accelerated by the addition of TiCl4. The polymer yield passes through a maximum on increasing the catalyst reaction time with or without monomer present. The active species are probably cations formed by dissociation of the reaction product of C2H5AlCl2 and TiCl4. The polymerization of isoprene with (C2H5)2AlX–TiCl4 (X = F, Br, Cl) has maximum activity at an Al/Ti mole ratio of 0.75 corresponding to conversion of R2AlX to RAIX2 which then reacts with remaining TiCl4. A proposed mechanism of cyclopolymerization of conjugated dienes involves monomer activation, i.e., conversion to cation radical by one-electron transfer to catalyst cation which is itself neutralized, addition of cation end of monomer cation radical to terminal or internal unsaturation of fused cyclohexane polymer chain, one-electron transfer from “neutral” catalyst to cation on polymer chain which is then transformed to a diradical which undergoes coupling to form a cyclohexene ring. The mechanism of the “living” polymerization involves addition of catalyst-activated monomer to a “dead” polymer with a terminal cyclohexene ring and regeneration of the active catalyst.

Some information concerning the mechanism of the radiolysis of perfluorinated carboxylic acids is presented from an examination of the e.s.r. spectra of radicals trapped in polycrystalline samples of the acids between 77 and 300 K. Three types of radicals have been identified in γ-irradiated samples of RCF2COOH (R = F, CF3, CF3CF2, C6H13, CF2COOH, CF2CF2COOH). These are (1) parent radical anions RCF2ĊOOH–, (2) primary fluoralkyl radicals RĊF2, and (3) secondary radicals RĊFCOOH. The radical anions lose F– on thermal annealing to yield additional RĊFCOOH radicals, but when samples containing RCF2ĊOOH– are u.v.-irradiated at 77 K these species disappear without the appearance of any identifiable radical product, as do the corresponding species in non-fluorinated carboxylic acids. The RĊF2 radicals are believed to originate from the cationic species formed in the initial ionization following proton transfer and elimination of CO2.

Complexes of overall formula TiAl2X8 · Ar (X = Cl, Br or I, Ar = benzene or hexamethylbenzene) and the complexes containing various amounts of Br or I in addition to Cl were prepared both by a direct synthesis — the reduction of titanium tetrahalide by aluminium in the aromatic solvent and in excess of the corresponding aluminium halide — and by halogen exchange between the complexes and aluminium halides. The interpretation of the electronic spectra of the complexes is given on the assumption of pseudooctahedral symmetry of the ligand field. The values of 10 Dq and B obtained are compatible with the assignment.