Kondensation von Cp2TiCl2 mit Tetraminen

Ohne Zusammenfassung     

Reduction—complexation des sulfures de phosphines par les fer-carbonyles

1-Phenyl-3,4-dimethylphosphole (L) yields the classic σ complex LFe(CO)₄ with Fe₂(CO)₉ and the unsual σ,π complex LFe₂(CO)₇ with Fe₃(CO)₁₂, whereas 1-t-butyl-3,4-dimethylphosphole (L′) with Fe₃(CO)₁₂ yields L′Fe₂(CO)₆ which belongs to a type already described in the literature. With Fe₂(CO)₉ at 85°C, the phosphole sulfide LS yields the two σ and σ,π complexes directly by reduction—complexation. This Fe₂(CO)₉ reduction—complexation process works only with phosphole and phospholene sulfides. However, with Fe(CO)₅ in great excess at 150°C, a general phosphine sulfide reduction—complexation procedure takes place. A study of the displacement of 1-phenyl-3,4-dimethyl-3-phospholene (L″) from its σ complex L″Fe(CO)₄ by trimethylphosphite has shown that L″ has a greater complexing ability toward iron than the phosphite, contrary to what could be expected from the work of Tolman on nickel complexes.     

Etude calorimetrique des enthalpies de dilution de NH3 dans le systeme binaire HF-NH3

Enthalpies of dilution of NH₃ in the binary system HF-NH₃ have been determined using a suitable home-made calorimeter. Compilation of the results gives the enthalpy of reaction of gaseous NH₃ with a HF-NH₃ solution, in the NH₃ low concentration region (x_NH3 < 14,6 %).     

Formation de radicaux libres dans des substitutions nucleophiles: Polymerisation du styrene par le systeme: thiolate de sodium-halogenure benzylique

The reaction between sodium thiolates and benzylic halides gives rise to free radicals, some of which are benzylic radicals characterized by ESR spectroscopy using the spin-trapping technique. Furthermore the studied reaction is able to initiate the radical polymerization of styrene. A model which rationalizes the experimental results is proposed.     

Cp2TiCl2 catalyzed one-pot synthesis of n-Bu3GeH from GeCl4

The reaction of GeCl₄ with n-BuMgCl in presence of a catalytic amount of Cp₂TiCl₂ gives n-Bu₃GeH and n-Bu₄Ge in ca. 70 and 25% yield, respectively. This method provides an industrially feasible one-pot synthesis for Bu₃GeH and Bu₄Ge. The reaction temperature and stoichiometry seem to be important in the distribution of the products. Apart from elemental analysis these compounds have been characterized by comparing their boiling points, NMR spectral data and GC assay with that of the authentic samples.     

Reduction—complexation des thiophosphinates par le nickelocene

2-Phenyl-1,3,2-dioxaphosphorinane rearranges at 250°C to afford 2-phenyl-2-oxo-l,2-oxaphospholane which is, in turn, converted into the 2-thio derivative by P₄S₁₀. This cyclic thiophosphinate reacts with nickelocene and allyl iodide to yield

(L = 2-phenyl-1,2-oxaphospholane) by reduction—complexation. The same scheme is successfully applied to the 1-oxa-2-phosphacyclohepta-4,6-diene nucleus. Thus, the P^IV=S reduction—complexation process works with POC compounds. This is not the case with PSC compounds (for example, with dithiophosphinates). Some chemistry of 2-phenyl-l,3,2-dithiaphosphorinane is also described: Arbuzov reaction with PhCH₂Br, thermal rearrangement and complexation with nickelocene and allyl iodide.     

Deshydrogenation d'alcools en composes carbonyles par le systeme CuCl/O2/Ligande

The dehydrogenation of alcohols to the corresponding carbonyl compounds by CuCl/O₂/ligand (L) shows relative rates of dehydrogenation according to the type of alcohol used; primary or secondary benzyl alcohols > allylic alcohols or aliphatic alcohols > cyclic alcohols. The rate of this reaction was found to be dependent upon the nature of the ligands used; e.g. phenanthroline 1–10 > bipyridyl 2,2' > TMEDA, etc. When L = phenanthroline 1–10 the catalytic effect, of the system ROH/CuCl/L (3:1:1), was found to be similar to the system ROH/CuCl/L (1:2:2). The pure oxygen was replaced by air without any noticeable change in the rate of the reaction. The primary aliphatic alcohols lead to the aldehydes containing 1, 2, etc. carbon atoms fewer than the starting alcohols.     

Etude de la structure K2NiF4 par la méthode des invariants,I. Cas des oxydes A2BO4

The study of the K₂NiF₄ structure by the “method of invariants” leads to the relationship

$\text{0.99615 V}\text{1}\text{3}\text{=β}{}_{\mathrm{B}}\text{+ψ}{}_{\mathrm{A}}\text{2}\text{1}\text{2}$

with V = a²c (β_B and ψ_A are invariant values associated with cations B and A) in compounds with K₂NiF₄ structures. Some values of ψ_A and examples are proposed.     

[Cp2TiCl2] as polymerization catalyst in aqueous medium: polymerization of styrene in water

The contrary to the general idea, an early transition metal organometallic compound, [Cp₂TiCl₂] has been found to be active catalyst for aqueous medium polymerization of styrene.     

Copolymerisation du trans-pentadiene-1,3 et de l'isoprene amorcee par le systeme triethylaluminium-orthotitanate de n-butyle

L'isoprene and 1,3-pentadiene can be polymerized in benzene solution with the use of a catalyst prepared from triethylaluminium and n-butyl orthotitanate. The structures of these copolymers are independent of Al/Ti molar ratio. There are more vinylic units in the copolymer than in the homopolymers. The determination of the monomer reactivity ratios, ozonolysis and pyrolysis show that copolymers are predominantly statistic with a slight tendency towards alternation.     

Inversion de polarite a4 des cetones α-alleniques par le groupe triphenylphosphonio

The a⁴ umpolung of α-allenic ketone sis performed using the triphenylphosphonio group. It results in inducing an electrophilic character at the carbon ψ to the carbonyl function and in changing the regioselectivity of the additions of active hydrogen compounds on the carbon-carbon double bond to give finally the adducts $\text{4}$ (Fig. 1).This new umpolung method is illustrated here in the case of the addition of methanol on allenyl methyl ketone $\text{1a}$ (Fig. 2).     

RESS技术制备负载型茂金属催化剂的表面特性研究

用X-射线光电子能谱法分析了超临界溶液快速膨胀法制得的二氯二茂钛(Cp₂TiCl₂)颗粒、聚苯乙烯(PS)颗粒和二氯二茂钛/聚苯乙烯(Cp₂TiCl₂/PS)负载型颗粒的表面化学性质,得到了三种不同颗粒的表面元素组成及元素结合状况,发现只有聚苯乙烯(PS)颗粒在喷射过程中吸附CO₂和标记物CH₃CH₂OH,而二氯二茂钛(Cp₂TiCl₂)颗粒和二氯二茂钛/聚苯乙烯(Cp₂TiCl₂/PS)负载型颗粒都不吸附CO₂和CH3CH₂OH,表明通过选择合适的操作条件,超临界溶液快速膨胀法制得的Cp₂TiCl₂/PS颗粒是以PS为内芯、Cp₂TiCl₂为外壳的负载型催化剂,为超临界溶液快速膨胀法制备负载型催化剂的新型工艺的可行性提供了依据。     

Reduction d'alcools allyliques fluores par le borohydrure de sodium

Reduction of 1,1-difluoro 1-alken 3-ols with sodium borohydride in diglyme gives 1,1-difluoro 2-alkenes by SN2' substitution of the hydroxy moiety.