Polymerization of 4-phenyl-1-butyne catalyzed by metathesis and Ziegler–Natta catalysts

The polymerization of 4-phenyl-1-butyne was carried out using metathesis and Ziegler-Natta catalysts. Especially, the Fe(acac)₃-AlEt₃ catalyst with toluene as a solvent produced an extremely high molecular weight polymer of M_w ≈ 10⁶. Solubility of the polymers at room temperature in organic solvents such as benzene, toluene, dichloromethane, chloroform, and THF was excellent despite their high molecular weights. It has been indicated that the polymer prepared by the Fe(acac)₃-AlEt₃ catalyst is of cis form with a high stereoregularity. © 1993 John Wiley & Sons, Inc.     

Vibrational spectroscopy and intramolecular dynamics of 1-butyne

Photodissociation of jet-cooled vibrationally excited 1-butyne, C(2)H(5)C[Triple Bond]C[Single Bond]H, coupled with mass spectrometric detection of H photofragments, facilitated measurements of action spectra and Doppler profiles, expressing the yield of the ensuing fragments versus the vibrational excitation and UV probe lasers, respectively. Both the action spectra and the simultaneously measured room temperature photoacoustic spectra in the 2nu(1), 3nu(1), and 4nu(1) C[Single Bond]H acetylenic stretch regions exhibit unresolved rotational envelopes with significant narrowing of the former due to temperature-related change in the rotational structure. The narrowing of the action spectrum in the 3nu(1) region exposed a resonance splitting, implying intramolecular vibrational energy redistribution (IVR) time of approximately 1 ps. Asymmetric rotor simulation of the band contours provided the rotational constants and estimates for the homogeneous broadening arising from IVR to the bath vibrational states. The homogenous linewidth of 4nu(1) is anomalously narrower than that of 2nu(1) and 3nu(1), indicating a longer lived 4nu(1) state despite the increasing background state density, suggestive of a lack of low-order resonances or of mode-specific coupling with the bath states. The Doppler profiles indicate that the H photofragments are released with low average translational energies, pointing to an indirect dissociation process occurring after internal conversion (IC) to the ground electronic state or after IC and isomerization to butadiene.     

Synthesis and optical limiting in copolymers of C_(60) and 1-phenyl-1-butyne

Since the discovery of the methods for mass production of fullerenes', there has beengreat interest in the development of fullerene-containing polymeric materials'-' becausesuitably designed fullerene polymers not only possess good processability but also exhibitinteresting materials properties'-'. We have also attached C,o to polyphenylacetylenechains by a WCI,~catalyzed copolymerization reaction'-'. In this letter, we chose anacetylene monomer, that is, l-phenyl-butyne (PB), which can not …     

Overtone spectroscopy of C-H ethyl stretches of 1-butyne

Room-temperature photoacoustic (PA) spectra and jet-cooled action spectra of the first to third overtone regions of the ethyl C-H stretches in vapor phase 1-butyne, CH3CH2C[Triple Bond]C-H, were measured. Both the PA and action spectra exhibit a complex multiple peak structure being better resolved and more pronounced in the latter, due to inhomogeneous structure reduction. The observed manifolds were analyzed in terms of a simplified joint local-/normal-mode (LM/NM) model accounting for two types of C-H stretches (methyl and methylene) and for Fermi resonances between stretches and deformations. The retrieved parameters, used for calculation of the eigenstates, come from the best-fit parameters based on the diagonalization of the vibrational Hamiltonian in the LM/NM basis. The parameters were obtained by comparing the eigenvalues and the sum of the squares of the expansion coefficients of the eigenvectors of the C-H stretches of methyl and methylene to the action spectra peak positions and intensities, respectively. This approximate model vibrational Hamiltonian is proposed to explain most observed spectral features, corresponding to C-H stretch bands and to combinations of C-H stretches and deformations, indicating the importance of the Fermi resonance. The model was also applied to calculate the dynamics of the C-H stretching modes resulting from coupling with the deformations, implying rapid initial state decay on subpicosecond time scale. Decays of several picoseconds were found for complete transfer of probability from the initially prepared state of methylene and methyl to the counterpart LM states.     

Living Polymerization of 1-Trimethylsilyl-1-propyne and 4-Methyl-2-pentyne by NbCl5-Based Catalysts

Sequential homopolymerization of disubstituted acetylenes 1-trimethylsilyl-1-propyne and 4-methyl-2-pentyne by NbCl₅–Ph₃SiH was investigated and the main evidence of living polymerization, namely, continuation of chain propagation after addition of a new portion of monomer was observed. AB and BA type block copolymers of 1-trimethylsilyl-1-propyne and 4-methyl-2-pentyne were synthesized by sequential polymerization of these monomers in presence of NbCl₅–based catalytic systems.     

Living polymerization of 4-methyl-2-pentyne and 1-trimethylsilyl-1-propyne initiated by NbCl5-Ph4Sn catalyst

The polymerization of 4-methyl-2-pentyne and 1-trimethylsilyl-1-propyne initiated by catalytic systems based on niobium pentachloride and Et₃SiH, Bu₄Sn, Ph₄Sn, and Ph₃SiH as cocatalysts has been investigated. Direct evidence for the living polymerization of 4-methyl-2-pentyne and 1-trimethylsilyl-1-propyne with the NbCl₅-Ph₄Sn catalytic system is derived. These are the linear molecular mass dependence on conversion and the continuation of chain propagation after introduction of a new monomer portion.     

Conformation-specific spectroscopy of 3-benzyl-1,5-hexadiyne

3-Benzyl-1,5-hexadiyne (BHD) was studied by a combination of methods, including resonance-enhanced-two-photon ionization, UV-UV hole-burning spectroscopy, resonant ion-dip infrared spectroscopy, and rotational band contour analysis. There are five conformations of BHD observed in the expansion with their 1<-- S0 origins occurring at 37520, 37565, 37599, 37605, and 37631 cm(-1). DFT calculations predict six low energy conformations. Conformational assignments have been made by comparison of the experimental infrared spectra in the alkyl and acetylenic CH stretch region to DFT vibrational frequency and infrared intensity calculations. Rotational band contours provided further confirmation of these assignments. The electronic origin shifts of BHD compare favorably to the electronic origin shifts of 5-phenyl-1-pentyne with the exception of one conformation. This conformation is unique in that it is the only structure with both acetylenic groups in the gauche position over the ring. This gauche-gauche conformation exhibits a perpendicular (b-type) transition and produces extensive vibronic coupling reminiscent of symmetric monosubstituted benzenes.     

Formation and structure of 1-Amino-4-methyl-4-(4-methyl-5-phenyl-1H-pyrazol-3-ylamino)-3-phenyl-4,5-dihydro-1H-pyrazol-5-one

The title compound 3 was obtained during the rearrangement of isoxazol-5-yl hydrazine 1 to 1-aminopyrazolone 2 at 115°. X-ray analysis of the corresponding benzylidene derivative allowed us to achieve the structure assignment.     

Conformation-specific infrared and ultraviolet spectroscopy of tyrosine-based protonated dipeptides

We present the spectroscopy and photofragmentation dynamics of two isomeric protonated dipeptides, H+AlaTyr and H+TyrAla, in a cold ion trap. By a combination of infrared-ultraviolet double resonance experiments and density functional theory calculations, we establish the conformations present at low temperature. Interaction of the charge at the N-terminus with the carbonyl group and the tyrosine pi-cloud seems to be critical in stabilizing the low-energy conformations. H+AlaTyr has the flexibility to allow a stronger interaction between the charge and the aromatic ring than in H+TyrAla, and this interaction may be responsible for many of the differences we observe in the former: a significant redshift in the ultraviolet spectrum, a much larger photofragmentation yield, fewer stable conformations, and the absence of fragmentation in excited electronic states.     

Vibrational assignments and theoretical calculations of 1-phenyl-5-mercaptotetrazole and 1-phenyl-5-mercaptotetrazolate

The infrared and Raman spectra of 1-phenyl-5-mercaptotetrazole (PMT) and 1-phenyl-5-mercaptotetrazole sodium salt in the solid state and in solution have been measured. Detailed vibrational assignments of PMT and 1-phenyl-5-mercaptotetrazolate (PMTA) have been performed. In order to give a firmer basis to the interpretation of the vibrational spectra, harmonic wavenumbers of PMT and PMTA have been calculated by means of MP2 and DFT/BPW91 calculations. The DFT calculations provide a satisfactory agreement between the calculated and observed wavenumbers without using scaling factors. Experimental evidence shows that PMT is present in the thione tautomer both in the solid state and in solution of polar solvents.     

Ultraviolet spectra of 2-phenyl-4- and 2-phenyl-5-azaindan-1, 3-diones

The UV spectra of 2-phenyl-4-azaindan-1, 3-dione (I), 2-phenyl-5-azaindan-1, 3-dione (II), and their N-methylbetaines are investigated. 2×10^–5 M aqueous alcoholic solutions of 2-phenyl-4-azaindan-1, 3-dione (I) contain the anionic form (IA), and in solutions of 2-phenyl-5-azaindan-1, 3-dione (II) the betaine form (IIB) is also in equilibrium with the anion (IIA). Solutions of I and II in 0.1 M sulfuric acid are characterized by a wide and rather intense absorption band at about 500 m, indicating the presence of a betaine form (IB and IIB). In 2M hydrochloric acid solution 2-phenylazaindan-1, 3-diones and their N-methylbetaines (III and IV) are protonated at the oxygen atom, giving the enol forms of the N-protonated or corresponding N-methylated 2-phenylazaindandiones.     

Tautomerism of 1-phenyl-3-methyl-4-benzyl-5-pyrazolone

The tautomerism of 1-phenyl-3-methyl-4-benzyl-5-pyrazolone —a side product in the reaction of acetoacetic ester with benzaldehyde phenylhydrazone — was studied by IR and PMR spectroscopy, and its thermodynamic characteristics were determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 355–359, March, 1991.     

Synthesis of 1-alkyl-5-phenyl-4(1H)pyrimidinones

1-Alkyl-5-phenyl-4(1H)pyrimidinones are readily synthesized by condensing β-(dimethylamino)-N-[(dimethylamino)methylene] atropamides with methyl or ethyl amine. The latter compounds are prepared from phenylacetamides and dimethylformamide dimethyl acetal.     

5-{[(4′-正戊基氧-4-联苯基基)羰基]氧}-1-戊炔的相转变与相结构

采用差示扫描量热(DSC)、一维(1D)广角X射线衍射(WAXD)、热台偏光显微镜(PLM-hotstage)等研究手段对含联苯液晶基元的侧链液晶聚炔单体5-{[(4′-正戊基氧-4-联苯基基)羰基]氧}-1-戊炔(A3EO5)的本体相转变和相结构进行了研究.DSC和1D-WAXD实验结果表明,A3EO5在升温和降温过程中均呈现四个相转变过程,形成双向性液晶.样品从各向同性态降温至室温过程中,首先形成近晶A相,随后进入层内排列具有准长程有序的近晶B相,继续降温将形成层内为正交排列的近晶E相,在此之后样品进入晶相.PLM结果指出样品在各向同性态降温过程中分别形成球状织构、角锥织构和同心圆弧织构.     

Synthesis of 3-R-Sulfanyl-5-amino-1-phenyl-1H-pyrazole-4-Carbonitriles

Russian Journal of Organic Chemistry - Previously unknown 3-R-sulfanyl-5-amino-1-phenyl-1H-pyrazole-4-carbonitriles were synthesized by reactions of 2-[bis(alkylsulfanyl)methylidene]malononitriles...     

Preparation of 3(5)-phenyl-1-hydroxypyrazole 2-oxide and 4-methyl-3(5)-phenyl-1-hydroxypyrazole 2-oxide

Nitrosation of acrylophenone oxime or of methacrylophenone oxime with n-butyl nitrite in the presence of pyridine and copper(II) sulfate gives the copper complexes of the title compounds. The free 1-hydroxypyrazole 2 -oxides are isolated by treating the copper complexes with dilute sodium hydroxide, filtration, and acidification of the basic filtrates. The title compounds are the first examples of 1-hydroxypyrazole 2 -oxides in which the C3(5) ring position is unsubstituted.