Silica-supported cyclopentadienyl-rhodium(I), -cobalt(I), and -titanium(IV) complexes

The silylated cyclopentadiene derivative, (MeO)₃Si(CH₂)₃C₅H₅, synthesised from commerically-available (MeO)₃Si(CH₂)₃Cl, has been used to prepare the complexes [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]Rh(CO)₂, [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]Rh(COD) (COD = cyclo-octa-1,5-diene), and [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]₂TiCl₂. The complex [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]TiCl₃, prepared by reaction of NaC₅H₄(CH₂)₃Si(OMe)₃ with TiCl₄ (1/1 molar ratio) and also by reaction of [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]Ti(OEt)₃ with CH₃COCl, proved to be very unstable. Attempts to synthesise the complex [η⁵-(MeO)₃Si(CH₂)₃C₅H₄](η⁵-C₅H₅)TiCl₂, either by reaction of [η⁵-(MeO)₃Si(CH₂)₃C₅H₄]TiCl₃ with NaC₅H₄ or reaction of (η⁵-C₅H₅)TiCl₃ with NaC₅H₄(CH₂)₃Si(OMe)₃, gave none of the expected product and only (η⁵-C₅H₅)₂TiCl₂ could be isolated from these reactions. The cyclo-octadiene rhodium complex supported on silica has been shown to be an efficient cyclotrimerization catalyst, and the silica-supported titanium complex (SIL-(CH₂)₃C₅H₄)₂TiCl₂ is, after reduction with butyllithium, an efficient and selective catalyst for the hydrogenation of alk-1-enes.     

Electron transfer reactions of V(IV) with Cl(I), Br(I) and I(I). A kinetic study

A kinetic study on the oxidation of V(IV) by chloramine-T (CAT) at pH 6.85 by N-bromo succinimide (NBS) in aqueous acetic acid–perchloric acid media and by N-iodo succinimide (NIS) in aqueous perchloric acid medium has been carried out. In all the systems studied the order with respect to the oxidant is unity. NBS and CAT oxidation reactions exhibited Michaelis–Menten type kinetics, and the NIS study indicated unit dependence on [substrate]. Independence on acidity has been observed in the case of CAT and NBS reactions, but NIS reactions exhibited inverse unit dependence on [acid]. Novel solvent influences have been noticed in the case of CAT reactions, but with NIS and NBS reactions retardation in the rate has been observed with an increase in the percentage of acetic acid. Plausible mechanisms consistent with the results have been postulated, and suitable rate laws in consonance with the postulated mechanisms have been derived.     

Die oxydimetrische Titration von Quecksilber(I) mit Cer(IV)-sulfat

Ohne Zusammenfassung     

Die Extraktion von Zirkonium(IV)- und Hafnium(IV)-Nitraten in Amylacetat (I), Isoamylalkohol (II) und Butylacetat (III)

Ohne Zusammenfassung     

Phenalenones. IV. Heterocycles from 3-hydroxyphenalenone (I)

3-Hydroxyphenalenone reacts with o-disubstituted benzenes (substituents: NH₂, OH, CH₂OH and SH), aliphatic and aromatic aldehydes to give the various heterocyclic compounds which are fused with phenalene ring. These reactions resemble those of 1,3-cyclohexanediones in many respects.     

Mandelazo I As A Reagent For Zr(IV) Determination

Abstract

A spectromeric study of the reaction of the Zr(IV) ions with Mandelazo I was carried out. Absorption spectra revealed that the maximum absorption of the zirconium compound appears at a wavelength (316 nm) different from the maxima of the reagent (253 and 390 nm). Beer-Lambert law is followed for zirconium concentrations of the order of 8.8x 10^?5 M (i.e. 8 μg Zr (IV)/mL). Possible interferences of ions such as Be(II), Cu(II), Zn(II), Al(III), Th(IV), U(VI), Mn(II), Fe(III), Co(II) and Ni(II) were investigated in connection with some masking agents such as SO₄ ^2- and C₂O₄ ^2-. Also, the solid state Zr(IV)-Mandelazo I compound was prepared and characterized by nitrogen and thermogravimetric analyses.     

Enantioselective Cyanosilylation of Ketones with Lithium(I) Dicyanotrimethylsilicate(IV) Catalyzed by a Chiral Lithium(I) Phosphoryl Phenoxide

A highly enantioselective cyanosilylation of ketones was developed by using a chiral lithium(I) phosphoryl phenoxide aqua complex as an acid/base cooperative catalyst. The pentacoordinate silicate generated in situ from Me₃SiCN/LiCN acts as an extremely reactive cyano reagent. Described is a 30 gram scale reaction and the synthesis of the key precursor to (+)‐13‐hydroxyisocyclocelabenzine.     

Oxopentacyano-complexes of molybdenum(IV) and tungsten(IV) in photolysis of octacyanometalates(IV)

Summary Ligand-field (LF) photolysis of aqueous alkaline solutions of K₄[M(CN)₈] (M = Mo or W) containing KCN produces [MO(CN)₅]^3– species. NaCs₂]MO(CN)₅] was isolated and characterised by u.v.-vis., i.r. and Raman spectroscopy. In addition, the reactions of [MO(OH)(CN)₄]^3– with free CN^– are described and the relations between octa-, penta- and tetra-cyanocomplexes are summarised.     

Thallium(I)-thiometallate(II,IV) vom Typ TI2MeMeIVS6

Thallium(I) Thiometallates(II, IV), Tl₂MeMe^IVS₆ The preparation and some properties of the compounds Tl₂MeMe^IVS₆ are reported, where Me^II = Pt, Pd, Ni; Me^IV = Pt, Zr, Sn, Ta. Their structure is discussed in relation to the structure of the alkali compounds A₂MeMe^IVS₆.     

Cu(I)-Ce(IV)-Y吸附剂的制备及其脱硫性能研究

采用液相离子交换Cu、Ce离子制备了Cu(I)-Y、Ce(IV)-Y和Cu(I)-Ce(IV)-Y吸附剂,利用XRD、BET等技术对吸附剂进行了表征。通过静态实验考察了制备条件对Cu(I)-Ce(IV)-Y吸附剂脱硫性能的影响,通过固定床实验研究了吸附剂的穿透硫容,同时,在含噻吩与苯并噻吩的正辛烷模拟油中,分别加入甲苯、环己烯、吡啶配成新的模拟油,探究了吸附剂的脱硫选择性。结果表明,离子交换时间48 h,焙烧温度550℃,Cu/Ce物质的量比1∶1下制备的Cu(I)-Ce(IV)-Y吸附剂具有适宜的脱硫活性。在含甲苯、环己烯模拟油中,Cu(I)-Ce(IV)-Y吸附剂具有最好的脱硫性能,相同浓度的甲苯、环己烯和吡啶对各吸附剂脱硫性能的影响顺序为吡啶环己烯甲苯。引入Cu+可改善吸附剂的脱硫活性,引入Ce4+可改善吸附剂对硫化物的选择性,Cu+和Ce4+的协同作用使Cu(I)-Ce(IV)-Y兼具有高的硫容和抗芳烃、烯烃能力。     

Photoelectron spectroscopy of actinide organometallic compounds I. Bis(cyclooctatetraene)actinide(IV) complexes

The He(I) photoelectron spectra of the antinocene species Th(cot)₂ and U(cot)₂ (cot = cyclooctatetraene) have been determined. The 5f metal ionization has been detected at the onset of the uranocene spectrum. The low ionization energy region of both spectra is discussed in terms of simple qualitative molecular orbital scheme.