Schiff base derivatives of lanthanons-synthesis of La(III), Pr(III) and Nd(III) derivatives of β-ketoimines derived from 2,4-pentanedione

Reactions of the isopropoxides of some of the lighter lanthanons with bidentate -ketoimines, such asAAH-n-C₄H₉ andAAH-C₆H₅ (donor system: N,OH) and tridentate -ketoimines such asAA(CH₂CH₂)H₂ andAA(CH₂CHCH₃)H₂ (donor system: HO,N.OH) have led to products of the typesLn(O-i-C₃H₇)_3n (AA-R) _n ,Ln(Oi-C₃H₇) (AAR') andLn ₂(AAR')₃ [Ln=La(III), Pr(III) or Nd(III);n=1 or 2;R=-n-C₄H₉ or-C₆H₅ andR'=-CH₂CH₂-or-CH₂CHCH₃-]. Some undergo exchange reactions with an excess oftert-butanol, leading to the corresponding complexesLn(O-tert-C₄H₉)_3n (AA-n-C₄H₉) _n andLn(O-tert-C₄H₉) (AA-CH₂CH₂). All these have been characterised by elemental analysis, molecular weight determinations and their ir spectra. A thermogravimetric analysis of the diisopropoxy derivatives has also been carried out.

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Schiff-Basen Derivate von Lanthaniden-Synthese von La(III), Pr(III) und Nd(III) chelaten mit -Ketoiminen

Zusammenfassung Reaktionen von Lanthanid-Isopropoxiden mit zweizähnigen -Ketoiminen [AAH-n-C₄H₉ undAAH-C₆H₅; Donorsystem: N,OH] und dreizähnigen -Ketoiminen [AA(CH₂CH₂)H₂ undAA(CH₂CHCH₃)H₂; Donorsystem: OH, N,OH] führten zu Produkten vom, TypLn(O-i-C₃H₇)_3-n (AA-R) _n ,Ln(O-i-C₃H₇) (AAR') undLn ₂(AAR')₃ [Ln=La(III), Pr(III) oder Nd(III);n=1 oder 2;R=n-C₄H₉ oder C₆H₅ undR'=CH₂CH₂ oder CH₂CHCH₃]. Einige Komplexe unterliegen bei Behandlung mit einem Überschuß vontert-Butanol einer Austauschreaktion, die zu den entsprechenden Butoxid-Komplexen führt [Ln(O-tert-C₄H₉)_3-n , (AA-n-C₄H₉) _n undLn(O-tert-C₄H₉) (AACH₂CH₂)]. Alle Derivate wurden mittels Elementaranalyse, Molgewichtsbestimmung und IR-Spektroskopie charakterisiert. Eine thermogravimetrische Analyse der Diisopropoxi-Derivate wurde ebenfalls ausgeführt.

     

Polymerization of silylacetylenes by W and Mo catalysts

Polymerization of HC?CSiMe₃ homologues (HC?CSiMe₂R; R = n-C₆H₁₃, CH₂CH₂Ph, CH₂Ph, Ph, and t-Bu) was studied by use of W and Mo catalysts. W catalysts provided polymers in good yields from all these monomers. Mo catalysts gave mainly a polymer from HC?CSiMe₂–t-Bu, but virturally only cyclotrimers from sterically less croweded monomers (R = n-C₆H₁₃, CH₂CH₂Ph, CH₂Ph, and Ph). Polymers with flexible R groups (n-C₆H₁₃, CH₂CH₂Ph, and CH₂Ph) were totally soluble, their number-average molecular weights being 7000–18,000. Polymers with inflexible R groups (Ph and t-Bu) were partly insoluble. Every polymer was a yellow rubber or powder, and had the structure, \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} [{\rm CH} = {\rm C}\left( {{\rm SiMe}_{\rm 2} {\rm R}} \right)\rlap{--} ]_n $\end{document}. The results were compared with the polymerization and polymer of HC?CSiMe₃.     

Proton and 13C NMR spectra of substituted methyl cyanopropionates: Effects of molecular asymmetry

The proton NMR spectra at 220 MHz of two series of substituted cyanopropionates, have been investigated. In addition the ¹³C spectra at 15 MHz of the series I were also studied. In I, where the R groups are diastereotopic, differences are observed in the proton chemical shifts of the CH₃ groups in R for R = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉, n-C₅H₁₁ and n-C₆H₁₃. In II [R′ = n-C₃H₇, CH(CH₃)₂, CH₂CH(CH₃)₂ and C(CH₃)₃] diastereoisomers are found with substantial differences in chemical shifts between corresponding protons. Coupling constants are interpreted in terms of conformational preferences for certain molecules in both series.     

Polymerization of cyclic esters of phosphoric acid. VI. Poly(alkyl ethylene phosphates). Polymerization of 2-alkoxy-2-oxo-1,3,2-dioxaphospholans and structure of polymers

Five-membered cyclic esters of phosphoric acid of the general formula: ? CH₂CH(R)OP(O)-(OR′)O? polymerize readily to solid, soluble polymers of high molecular weight without any rearrangement known for various tri- and pentavalent organophosphorus monomers. ¹H-, ¹³C-, and ³¹P-NMR spectra of polymers confirmed their linear structure: where R is H, with R′ = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇; n-C₄H₉, CCl₃CH₂, or C₆H₅, or R is CH₂Cl and R′ is C₂H₅. The use of n-C₄H₉Li, (C₅H₅)₂Mg, or (i-C₄H₉)₃Al as initiators leads to polymers with M _n = 10⁴–10⁵.     

Organische Phosphorverbindungen XXXVII. Darstellung und Eigenschaften von Bis-(dialkoxyphosphonyl-methyl)-, Bis-(alkoxyphosphinyl-methyl)-und Bis-(oxophosphoranyl-methyl)-phosphinsäureestern sowie der entsprechenden Säuren [1]

Bis-chloromethyl-alkyl-and - aryl-phosphine oxides, (CICH₂₎₂P(O)R, which are obtained by reaction of (CICH₂₎₂P(O)Cl with GRIGNARD reagents, undergo a MICHAELIS -ARBUSOV reaction when heated for several hours with trivalent phosphorus esters (phosphites, phosphonites, or phosphinites) at 170–180°C. The reaction affords bis-(dialkyloxyphosphonyl-methyl)-, bis (alkyloxyphosphinyl-methyl)-, and bis-(oxophosphoranyl-methyl)-, -alkyl- or -aryl-phosphine oxides, R(O)P[CH₂P(O)R′R″]₂ R = CH₃, C₂H₅, n-C₈H₁₇, n-C₁₂H₂₅, C₆H₅; R′ and R″ = C₂H₅O, C₄H₉O, C₆H₅, CH₃ in good yields. Conversion of the compounds containing alkyloxy groups to the free acids is achieved by refluxing with conc. HCl. Bis-(dihydroxyphosphonyl-methyl)-dodecylphosphine oxide, n-C₁₂H₂₅(O)P[CH₂P(O) (OH)_2]2, obtained by hydrolysis of the all-ethyl ester, titrates in aqueous solution as a tetrabasic acid with breaks at pH = 4 (two equivalents), pH = 6,9 (one equivalent) and pH = 9,6 (one equivalent). This acid, its disodium salt (m. p. 405–410°) and its tetrasodium salt (m.p. > 460°) are surface active and are excellent chelating agents. The ¹H- and ³¹P-NMR. spectra of all the compounds prepared are discussed.     

Solid-state chlorodecarboxylation of mono- and dicarboxylic acids with the Pb(OAc)<Subscript>4</Subscript>-MCl system

Solid state reactions of acids RCOOH (R = n-C₇H₁₅, BuC(Et)H, n-C₉H₁₉, PhCH₂, PhCH₂CH₂, H₂C=CH(CH₂)₈, or MeOOC(CH₂)₃) with Pb(OAc)₄ combined with KCl, NaCl, CdCl₂, or NH₄Cl in the absence of a solvent and without mechanical activation afford chlorohydrocarbons RCl. The corresponding reactions of acids HOOC(CH₂)_nCOOH (n = 3–6) give dichloroalkanes Cl(CH₂)_nCl and γ-butyrolactone (n = 3).__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2105–2109, October, 2004.     

Polymerization of 1-methylthio-1-alkynes and polymer properties

Polymerization of 1-methylthio-1-alkynes (MeSC?CR; R = Et, n-Bu, n-C₆H₁₃, and n-C₈H₁₇) was studied by use of transition metal catalysts. A 1 : 2 mixture of MoCl₅ and Ph₃SiH provided polymers having M?_w over 1 × 10⁵ in 30–50% yields from these monomers. The length of the alkyl group hardly affected the polymerization. The monomer, MeSC?C-n-C₆H₁₃, showed low reactivity in homopolymerization, but higher reactivity than that of MeC?C-n-C₅H₁₁ in copolymerization. Poly(1-methylthio-1-alkyne)s were colorless solids, and those with long alkyl pendants (R = n-C₆H₁₃, n-C₈H₁₇) were soluble in various organic solvents. The present polymers were thermally more stable than poly(2-alkyne)s, the corresponding hydrocarbon polymers.     

Reactions of nucleophilic addition of primary amines to the nitrilium derivative of the <Emphasis Type="Italic">closo</Emphasis>-decaborate anion [2-B<Subscript>10</Subscript>H<Subscript>9</Subscript>(N≡CCH<Subscript>3</Subscript>)]<Superscript>−</Superscript>

Compounds (Bu₄N)[2-B₁₀H₉{NH=C(NHR)CH₃}]⁻ are obtained by reactions of the tetrabutylammonium salt of the [2-B₁₀H₉(N≡CCH₃)]⁻ anion with aliphatic and aromatic primary amines RNH₂ (R = n-C₃H₇, n-C₄H₉, cyclo-C₅H₉, C₆H₅, cyclo-C₆H₁₁, n-C₆H₁₃, C₇H₇, C₈H₈NH₂, C₆H₄NO₂, and C₁₈H₃₇) and identified by IR, ESI/MS, and NMR (¹H, ¹¹B, and ¹³C) spectroscopy. The structures of the amidine-type derivatives [2-B₁₀H₉{Z-NH=C(NH-cyclo-C₅H₉)CH₃}]⁻ and [2-B₁₀H₉{Z-NH=C(NH-C₇H₇)CH₃}]⁻ are determined by X-ray diffraction.     

13C n.m.r. studies of organosilanes: II—substituent chemical shift parameters for alkoxysilanes

The ¹³C n.m.r. spectra of forty alkoxysilanes of the general type X_nSi(OR)_4–n (X = CH₃, C₆H₅, H; R = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉, i-C₄H₉, s-C₄H₉, n-C₅H₁₁, CH(CH₃)(C₆H₅), C₆H₅) have been recorded and assigned. The chemical shifts of the α-carbon resonances of the alkoxy groups are shown to depend on both the nature of the alkoxy group and the number and type of substituents on the silicon. Regression analyses of the data give empirical substituent chemical shift (SCS) parameters for the silyl substituents. The β-carbon resonances are shown to be dependent on the presence of the silyl group, but not the specific silyl substituents.     

Segmented liquid crystalline polyesters with allyl group as lateral substituent

The synthesis and a partial characterization of segmented liquid crystalline polymers with 3,3′-diallyl-4,4′-dihydroxybiphenyl unit in the rigid moiety is reported. The general formula of polymers is [-p-C₆H₄-COO-p-C₆H₃(R)-p-C₆H₃(R)-OOC-p-C₆H₄-O-(CH₂)_nO-]_x, with n = 6, 8, 10, 12, and R =  CH₂ CHCH₂. All polymers have nematic liquid-crystalline behavior. At room temperature, annealed fiber samples of polymers show a complex polymorphism. Three phases have been isolated with very large unit cells accommodating 6 or 12 chains. The projection of the molecular packing in a plane perpendicular to the c axis is characterized by the organization of chains in a two-dimensional hexagonal or quasi-hexagonal array. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. B Polym. Phys. 36: 2371–2378, 1998     

Acetyl-containing phosphine oxides as extractants for actinides and lanthanides

Extraction capability and selectivity of acetyl-containing phosphine oxides R₂P(O)CMe₂CH₂C(O)Me (R = Pr, Bu, n-C₅H₁₁, n-C₆H₁₃, n-C₈H₁₇, Ph) toward actinides (U^VI, Th^IV) and trivalent lanthanides (La^III, Nd^III, Ho^III, Yb^III) were studied. The new ligands were shown to be more efficient and selective in the extraction of uranium, thorium, and heavy lanthanides from nitric acid solutions into chloroform as compared to the known extractants such as carbamoylphosphine oxide Ph₂P(O)CH₂C(O)NBu₂, trioctylphosphine oxide (n-C₈H₁₇)₃P(O), and tributyl phosphate (n-BuO)₃P(O).     

Magnetische Untersuchungen an Komplexen von La(III), Pr(III) und Nd(III) mitSchiffschen Basen

Specific magnetic susceptibilities (_s) of several newly synthesized chelates of some of the lanthanons [La(III), Pr(III) and Nd(III)] are reported. These derivatives are of the general type,Ln(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n [where,Ln=La(III), Pr(III) or Nd(III);n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄] and have been prepared by the reaction of the alkoxides of the lanthanons withSchiff bases such as benzylidene-2-hydroxyethylamine (C₆H₅CHNCH₂CH₂OH), benzylidene-2-hydroxy-n-propylamine (C₆H₅CHNCH₂CHOHCH₃) and benzylidene-o-aminophenol (C₆H₅CHNC₆H₄OH) in different molar relations in dry benzene.The resulting crystalline derivatives are non-volatile, light to deep yellow or blackish in colour. These tend to polymerize on keeping as shown by their insoluble nature and higher melting points, the polymerisation possibly occurring by the intermolecular coordination through oxygen atoms as reported earlier¹.UsingGouy method², the bis-isopropoxy mono-Schiff base and mono-isopropoxy bis-Schiff base complexes of La(III) have been shown to be diamagnetic, with _s values being in the range of –0.32 to –0.45×10^–6 and –0.39 to –0.55×10^–6 c.g.s. units at 305 K respectively.In the remaining derivatives, Pr(O-i-C₃H₇)_3–n (C₆H₅CH NRO) _n and Nd(O-i-C₃H₇)_3–n (C₆H₅CHNRO) _n (where,n=1 or 2 and R=CH₂CH₂, CH₂CHCH₃ or C₆H₄) the magnetic moment values range between 3.25 to 3.32 and 3.30 to 3.33 _B respectively indicating their paramagnetic nature.     

Luminescent Amphiphilic 2,6‐Bis(1,2,3‐triazol‐4‐yl)pyridine?Platinum(II) Complexes: Synthesis,Characterization, Electrochemical,Photophysical, and Langmuir–Blodgett Film‐Formation Studies

A new series of platinum(II) complexes with tridentate ligands 2,6‐bis(1‐alkyl‐1,2,3‐triazol‐4‐yl)pyridine and 2,6‐bis(1‐aryl‐1,2,3‐triazol‐4‐yl)pyridine (N7R), [Pt(N7R)Cl]X ( 1 – 7 ) and [Pt(N7R)(C?CR′)]X ( 8 – 17 ; R=n‐C₄H₉, n‐C₈H₁₇, n‐C₁₂H₂₅, n‐C₁₄H₂₉, n‐C₁₈H₃₇, C₆H₅, and CH₂‐C₆H₅; R′=C₆H₅, C₆H₄‐CH₃‐p_, C₆H₄‐CF₃‐p, C₆H₄‐N(CH₃)₂‐p, and cholesteryl 2‐propyn‐1‐yl carbonate; X=OTf^?, PF₆^?, and Cl^?), has been synthesized and characterized. Their electrochemical and photophysical properties have also been studied. Two amphiphilic platinum(II)? 2,6‐bis(1‐dodecyl‐1,2,3‐triazol‐4‐yl)pyridine complexes ( 3‐Cl and 8 ) were found to form stable and reproducible Langmuir–Blodgett (LB) films at the air/water interface. These LB films were characterized by the study of their surface‐pressure–molecular‐area (π–A) isotherms, XRD, and IR and polarized‐IR spectroscopy.     

Practical,stable standards for the reversed phase HPLC analysis of peptidic leukotrienes

The stable glutathione derivatives 1, R = n-C₆H₁₃ and R = n-C₈H₁₇, are useful as reference compounds for the identification and quantitation of leukotrienes C₄, D₄ and E₄ by reversed phase HPLC analysis.     

Copolymers of Maleic Anhydride and Methylene Alkanes: Synthesis,Modification, and Pour Point Depressant Properties

Copolymers with the equimolar composition and presumably alternating microstructure are synthesized by the radical copolymerization of methylene alkanes, the products of dimerization of α-olefins with the general formula RCH₂CH₂C(=CH₂)R (R = n-C₄H₇, n-C₆H₁₃, n-C₈H₁₇, n-C₁₀H₂₁, n-C₁₂H₂₅), with maleic anhydride. The products of reactions between the obtained copolymers and 1-octadecanamine or 1-octadecanol are isolated and spectrally characterized. The depressor efficiency of the copolymers with respect to the solutions of paraffins in n-alkanes is studied. Qualitative differences between the copolymers of maleic anhydride with methylene alkanes and reference copolymers based on 1-octadecene are estimated using vibrational viscometry combined with analysis of the size and morphology of paraffin crystals. It is shown that the copolymers with methylene alkanes more effectively decrease the cold filter plugging point (CFPP) of paraffin solutions in n-decane.     

Massenspektrometrische Untersuchungen an Organophosphorverbindungen. II—Elektronenstoßinduzierte Fragmentierungen von Tetraorganodiphosphandisulfiden

The behaviour under electron impact (70 eV) which includes some rearrangement processes of some tetraorganodiphosphanedisulfides R₂P(S)-P(S)R₂ (R ? CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, C₃H₅, C₆H₅) and CH₃RP(S)–P(S)CH₃R (R ? C₂H₅, n-C₃H₇, n-C₄H₉, C₆H₅, C₆H₅, C₆H₅,CH₂) is reported and discussed. Fragmentation patterns which are consistent with direct analysis of daughter ions and defocusing metastable spectra are given. The atomic composition of many of the fragment ions was determined by precise mass measurements. In contrast to compounds R₃P(S) loss of sulphur is not a common process here. The first step in the fragmentation of these compounds is cleavage of one P–C bond and loss of a substituent R?. The second step is elimination of RPS leading to [R₂PS]⁺ from which the base peaks in nearly all the spectra arise. The phenyl substituted compounds give spectra with very abundant [(C₆H₅)₃P]^+. and [(C₆H₅)₂CH₃P]^+. ions respectively, resulting from [M]^+. by migration of C₆H₅. Rearrangement of [M]^+. to a 4-membered P-S ring system prior to fragmentation is suggested.     

Tin(IV) complexes of schiff bases derived from pentane-2,4-dione or 2-hydroxy-1-naphthaldehyde

The 1∶2 molar reactions of tin(IV) chloride with the Schiff bases, CH₃C(OH):CHC(CH₃):NR and 2 HOC₁₀H₆CH:NR′ (where R=C₂H₅,n-C₃H₇ orn-C₄H₉ and R′=C₆H₅, C₂H₅,n-C₄H₉ ort-C₄H₉) have resulted in the synthesis of SnCl₄·(SBH)₂ type derivatives (whereSBH represents the Schiff base molecule). These have been characterized by elemental analysis, conductivity measurements and IR spectral studies.     

Demercuriation reactions of the complexes [(PPh3)2RPtHgR′] containing platinum-mercury bonds

The compounds [(PPh₃)₂,RPtHgR′] (R = CH₃, R′= 2,5-C₆H₃Cl₂, 2,3,4- and 2,4,6-C₆H₂Cl₃, 2,3,4,5-, 2,3,4,6- and 2,3,5,6-C₆HCl₄, C₆Cl₅; R = Et, R′ = 2,5-C₆H₃Cl₂, 2,4,6-C₆H₂Cl₃; R = 2-C₆H₄Cl, R′=2-C₆H₄(CH₃)) have been prepared by the reactions of RHgR′ with Pt(PPh₃)₃, in order to study their possible use as intermediates in the preparation of diorganoplatinum complexes with different organic ligands. The dependence of J(³¹P-¹⁹⁵Pt) on slight differences in the electronic character of the ligand R′ in the series of compounds [(PPh₃)₂(CH₃)Pt-HgR′] has been studied.     

Study on ketalization reaction of poly(vinyl alcohol) by ketones. VIII. kinetic study on acetalization and ketalization reactions of poly(vinyl alcohol)

The kninetics of acid-catalyzed acetalization and ketalization of poly(vinyl alcohol) (PVA) were systematically studied in completely homogeneous media with carefully selected solvents. Thus the acetalization reaction was run in water with six aldehydes [R₁CHO (R₁ = H, CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, ClCH₂)], whereas the ketalization in dimethylslfoxide with 11 ketones [R₂CH₃CO (R₂ = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉, i-C₄H₉, tert-C₄H₉, C₆H₅CH₂, C₆H₅CH₂CH₂), cyclopentanone, and cyclohexanone]. The latter was difficult to proceed in aqueous media. Both reactions were reversible and bimolecular and, despite the use of different solvents, gave similar heats of reaction (7.5 kcal/mol) and activation energies (ca. 15 kcal/mol) except for the case of formaldehyde and chloroacetaldehyde; however the equilibrium constants at 25°C showed that the acetalization is thermodynamically much more favored than the ketalization (ca. 5000 vs. 0.01–0.9), probably because of steric hindrance of the ketone substrate. The rate constants of hydrolysis (reverse reactions) for the poly(vinyl acetal) and poly(vinyl ketal) followed the Hammett-Taft equation to give a single p* (=3.60) that is very close to that for the hydrolysis of diethyl acetal and ketal. From these and other data, it was concluded that the polymer hydrolysis, as well as PVA acetalization and ketalization, are all electrophilic reaction where the formation of hemiacetal or hemiketal is the rate-determining step. © 1996 John Wiley & Sons, Inc.     

The use of transition-state theory to extrapolate rate coefficients for reactions of oh with alkanes

A method is described for extrapolating existing experimental data on the reactions of OH radicals with alkanes to higher temperatures using conventional transition-state theory. Expressions are developed for the estimation of the structural properties of the activated complex necessary for calculating ΔS^± and ΔH^±. The vibrational frequencies and internal rotations of the activated complex are given by those of the reacting alkane or the analogous alcohol and a set of additional internal modes that is the same for all OH + alkane reactions considered. Differences between primary, secondary, and tertiary hydrogen attack are discussed, and the validity of representing the activated complexes of all OH + alkane reactions by a fixed set of vibrational frequencies and other internal modes is evaluated. Calculations are presented for the reaction of OH with CH₄, C₂H₆, C₃H₈, n-C₄H₁₀, i-C₄H₁₀, c-C₄H₈, c-C₅H₁₀, c-C₆H₁₂, (CH₃)₂CHCH(CH₃)₂, (CH₃)₃CCH(CH₃)₂, (CH₃)₄C, and (CH₃)₃CC(CH₃)₃, and the results are compared with experiments.