Laser flash photolysis formation and direct kinetic studies of manganese(V)-oxo porphyrin intermediates

Irradiation of porphyrin-manganese(III) perchlorate complexes in acetonitrile with 355 nm laser light gave MnV-oxo intermediates that were characterized by their UV-vis spectra and reactivities. The MnV-oxo species of tetrakis(pentafluorophenyl)porphyrin (2), tetraphenylporphyrin (4), and tetra-(4-(N-methylpyridiniumyl))porphyrin (6) were generated. Second-order rate constants for reactions of 2 with substrates were as follows: 6.1 x 105 M-1 s-1 (cis-stilbene), 1.3 x 105 M-1 s-1 (diphenylmethane), 1.3 x 105 M-1 s-1 (ethylbenzene), and 0.55 x 105 M-1 s-1 (ethylbenzene-d10). In oxidations of cis-stilbene and diphenylmethane, the order of reactivity of the MnV-oxo species was 2 > 6 > 4.     

Esr and electronic absorption spectra of the products of deprotonation of iron arene-cyclopentadienyl complexes

Paramagnetic d⁷ complexes have been obtained by reducing deprotonated arenecyclopentadienyliron borofluorides (arene  diphenylmethane, fluorene, hexamethylbenzene) with sodium. The interaction of deprotonated d⁷ complexes with ethanol leads to neutral d⁷ complexes which are formed by direct reduction of the initial cations with sodium. Hexamethylbenzenecyclopentadienyliron was shown to undergo deprotonation under the action of sodium.The electronic absorption spectra of the deprotonated complexes have been studied. Analysis of the positions and intensifies of the absorption bands made it possible to draw some structural conclusions about deprotonated arene ligands.     

SO42-/ZrO2催化氯化苄与苯烷基化反应的气相色谱-质谱法分析

采用气相色谱-质谱法(GC/MS)对SO42-/ZrO2固体超强酸催化氯化苄与苯烷基化反应产物的组成与结构进行了分析,并对SO42-/ZrO2催化的选择性进行了初步探讨。结果表明:SO42-/ZrO2固体超强酸对氯化苄与苯的烷基化反应具有良好的催化活性,反应产物主要为二苯甲烷、苄基二苯甲烷与氯甲基二苯甲烷等7种苄基化物。SO42-/ZrO2固体超强酸催化的产物选择性与经典Lew is酸催化特征基本一致。     

The role of geometry on regioselectivity and rate of fluorination of fluorene and diphenylmethane with Selectfluor F-TEDA-BF4

Diphenylmethane and fluorene were used as target molecules in an investigation of the effect of the geometry of aromatic molecules on the regioselectivity and rate of fluorination with 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor F-TEDA-BF4). In acetonitrile at 80 degrees C ring fluorination of diphenylmethane was accompanied by oxidation of the saturated carbon atom, while in trifluoroacetic acid only ring fluorination with an ortho-para regioselectivity of 1.8:1 was observed. Fluorene was converted in acetonitrile as well as in trifluoroacetic acid into 2- and 4-fluoro substituted products in the relative ratio of 2:1 and 1.2:1, respectively. The reactions in acetonitrile obey a simple rate equation: v = d[F-TEDA]/dt = k2 x [F-TEDA] x [Substrate] and the second order rate constants for the reactions in acetonitrile at 65 degrees C were determined; values of 0.6 x 10(-4) M-1 s-1 for diphenylmethane and 35.5 x 10(-4) M-1 s-1 for fluorene were obtained. The reaction rates for the various functionalisations of fluorene relative to those for diphenylmethane were found to be considerably influenced by the type of functionalisation. Relative rate factors (k(rel) = k2(fluorene)/k2(diphenylmethane)) with values between 59 for fluorination and 712 for chlorination were determined, while the corresponding data for the biphenyl/diphenylmethane pair were only slightly dependent on the type of functionalisation. A reaction pathway involving electron transfer, thus forming cation radical intermediates, was proposed as the main process in the case of fluorination of fluorene with F-TEDA-BF4.     

The formation of bifurcated charge transfer complexes with molecular iodine

I₂ complexes with triptycene and several di- and triaryl derivatives of methane and ethane were studied. For these complexes the values of λ_CT are virtually identical to those reported for the complexes with the analogous monoaryl donors, while the values of λ for their blue shifted I₂ peaks are significantly lower than those for the monoaryl complexes. Both the equilibrium constants and - ΔH⁰ values for the formation of complexes from the components lead to the conclusion that the complexes with the di- and triaryl compounds are more stable than those with the monoaryl donors. For the diaryl donors, the ΔS⁰₂₉₈ values for complex formation are less favorable than those of the monoaryl donors. The dipole moment for I₂ in diphenylmethane is larger than the moment of I₂ in toluene. All of these observations can be explained by taking into account the transannular effect of one aromatic ring on another and viewing the complexes as bifurcated ones in which the I atom at one end of an I₂ molecule simultaneously interacts with two rings in the donor molecules.     

The synthesis of some complexed ketones or sulfones by oxidation of η-arene-η-cyclopentadienyliron cations or η-arenedi-η-cyclopentadienyliron dications

Di-η⁵-cyclopentadienyliron complexed dications of 9,10-dihydroanthracene, xanthene, thioxanthene and diphenylmethane derived from ligand exchange reactions but without their prior isolation were oxidized with KMnO₄ to give, respectively, the dications of anthraquinone, xanthone, thioxanthone and benzophenone, isolated as their dihexafluorophosphate salts. Cyclopentadienyliron complexes of arenes containing a sulfide function were oxidized by m-chloroperbenzoic acid to the corresponding complexed sulfones, and sulfones prepared in this way include the hexafluorophosphate salt of the η⁶-p-tolysulfonylbenzene, thioxanthene-10,10-dioxide, 9,9-dimethylthioxanthene-10,10-dioxide or dibenzothiophene-9,9-dioxide-η⁵-cyclopentadienyliron cation.     

Synthesis of polyalkylenearyls Communication 2. Polycondensation of 1,2-dichloroethane with diarylalkanes

Summary A study was made of the poly condensation of 1,2-dichloroethane with bibenzyl. It was shown that 1,2-dichloroethane polycondenses with biphenyl, but not with diphenylmethane.     

Synthesis of Isatin Derivatives

Reactions were studied of isatin sodium salt with bromocyclohexane, p-ethoxyphenyl chloroethyl ketone, 4,4'-di(chloromethyl)biphenyl, and 4,4'-(dichloromethyl)diphenylmethane. N-cyclohexylisatin, p-ethoxyphenyl N-isatinoethyl ketone, 4,4'-di(N-isatinomethyl)biphenyl, 4-chloromethyl-4'(N-isatinomethyl)biphenyl, 4,4'-di(N-isatinomethyl)diphenylmethane, 4-chloromethyl-4'(N-isatinomethyl)diphenylmethane, and 4-(N-morpholinomethyl)-4'-(N-isatinomethyl)diphenyl were synthesized.     

Simultaneous Enantioseparation and Rapid Determination of Atenolol and Amlodipine Besylate by Capillary Electrochromatography

Chromatographia - Simultaneous enantioseparation and rapid determination method of atenolol (AN) and amlodipine besylate (AMB) was firstly established using diphenylmethane...     

Synthesis,structure, and solvent-extraction properties of tridentate oxime ligands and their cobalt(II), nickel(II), copper(II), zinc(II) complexes

Synthesis of four different types of ligands Ar[COC(NOH)R] _n (Ar = biphenyl, n = 1, HL¹; Ar = biphenyl, n = 2, H₂L²; Ar = diphenylmethane, n = 1, HL³; Ar = diphenylmethane, n = 2, H₂L⁴; R = furfurylamine in all ligands) and their dinuclear Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ complexes is reported herein. These compounds were characterized by elemental analysis, ICP-OES, FT-IR spectra, and magnetic susceptibility measurements. The ligands were further characterized by ¹H NMR. The results suggest that dinuclear complexes of HL¹ and HL³ have a metal to ligand mole ratio of 2: 2 and dinuclear complexes H₂L² and H₂L⁴ have a metal to ligand mole ratio of 2: 1. Square pyramidal or octahedral structures are proposed for complexes of oxime ligands. Furthermore, extraction abilities of the four ligands were also evaluated in chloroform using selected transition metal picrates such as Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Pb²⁺. The ligands show strong binding ability towards Hg²⁺ and Cu²⁺ ions.     

“Slow exchange” of unpaired electron in diphenylmethane an ion-radical

Conclusions In diethyl ether, containing 10% hexametapol, in the EPR spectra of the anion-radicals obtained by the action of potassium on diphenylmethane, a transition from the spectra, corresponding to a dynamic delocalization of the unpaired electron throughout the entire diphenylmethane molecule, to spectra that testify to its localization in one phenyl ring, is realized when the temperature is lowered.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2370–2371, October, 1973.     

新的二苯并环状溴鎓盐的合成及性质研究

以4,4'-二取代联苯(或4,4'-二取代二苯甲烷)为原料合成了几种新的3,7-二取代二苯并环状溴(鎓)盐.对几种溴(鎓)盐与KBH₄及与NaN₃的反应进行了研究.结果表明,前一反应主产物为2-溴-4,4'-二取代联苯(或2-溴-4,4'-二取代二苯甲烷),后一反应的主产物为2-叠氮基-2'-溴-4,4'-二取代联苯(20a-20d).通过20a-20d的热反应合成几种新的多取代咔唑(21a-21d).     

Photochemical reduction of uranyl ion with aromatic alkanes

Uranyl ion is photochemically reduced to uranium(IV) in the presence of diphenylmethane and triphenylmethane. Quantum yields for uranium(IV) formation are accelerated with time suggesting the free radical formation, which triggers off a secondary reaction. Lower quantum yield and higherK _sv value for photochemical reduction of uranyl ion with triphenylmethane relative to the respective values observed with diphenylmethane reveals the competition between photophysical and photochemical deactivation of excited uranyl ion due to the presence of three and two phenyl groups in respective aromatic hydrocarbons for photophysical deactivation.     

Design and DNA binding of an extended triple-stranded metallo-supramolecular cylinder

A new tetracationic triple-stranded supramolecular cylinder is prepared from a bis(pyridylimine) ligand containing a diphenylmethane and two ketimine groups in the spacer. The cylinder is longer and slightly wider than the corresponding cylinder containing just diphenylmethane spacers. Inter-strand CH...pi interactions are not observed and this affects the relay of the chiral information within the cylinder; a mixture of rac and meso isomers results, with the meso isomer being the dominant solution species and characterised in the solid state by crystallography. This new cylinder does bind to DNA as confirmed by induced circular dichroism signals in both the metal-to-ligand charge transfer (MLCT) and in-ligand bands of the cylinder. Flow linear dichroism demonstrates that the cylinder binds to DNA in a specific orientation(s) and is consistent with (major) groove-binding as seen for the shorter cylinder. Some DNA bending/coiling is observed but the effect is much less dramatic than observed for the cylinder with diphenylmethane spacers confirming that coiling is not solely a consequence of the tetracationic charge, but rather is related to the precise size and shape of the cylinder.     

N-methyl-substituted aromatic polyamides

A series of N-methyl-substituted aromatic polyamides derived from the secondary aromatic diamines 4,4′-bis(methylamino)diphenylmethane, 3,3′-bis(methylamino)diphenylmethane, 4,4′-bis(methylamino)benzophenone or 3,3′-bis(methylamino)benzophenone and isophthaloyl dichloride, and terephthaloyl dichloride or 3,3′-diphenylmethane dicarboxylic acid dichloride was prepared by high-temperature solution polymerization in s-tetrachloroethane. Compared with analogous unsubstituted and partly N-methylated aromatic polyamides, the full N-methylated polyamides exhibited significantly lower glass transition temperatures (T_g), reduced crystallinity, improved thermal stability, and good solubility in chlorinated solvents.     

Highly unsaturated polymers

Conclusions A means of synthesizing soluble polyacetylenic polymers of the diphenylmethane series was discovered.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 900–904, April, 1967.     

One new diphenylmethane glycoside from the leaves of Psidium guajava L

To investigate the chemical constituents of Psidium guajava L, the EtOH/H(2)O extract of the fresh leaves was subjected to various chromatography. One diphenylmethane, one benzophenone, and eight flavonoids were isolated and elucidated as 2,6-dihydroxy-3-formaldehyde-5-methyl-4-O-(6″-O-galloyl-β-D-glucopyranosyl)-diphenylmethane (1), 2,6-dihydroxy-3,5-dimethyl-4-O-(6″-O-galloyl-β-D-glucopyranosyl)-benzophenone (2), kaempferol (3), quercetin (4), quercitrin (5), isoquercitrin (6), guaijaverin (7), avicularin (8), hyperoside (9), reynoutrin (10) by spectroscopic methods, including 1D and 2D NMR and HR-ESI-MS spectrometry as well as by comparison with published data. Compounds 5 and 10 are obtained from P. guajava for the first time, and compound 1 is a new diphenylmethane compound.     

Stereo-selective synthesis of cis-alkenes/halo-alkenes by reaction of diphenylmethane with ethynylbenzenes via sp C-H bond activation promoted by iron salts

A stereo-selective reaction for the synthesis of cis-alkenes/halo-alkenes from diphenylmethane and ethynylbenzenes was developed in the presence of iron(III) bromide or chloride. Alkenyl bromides/chlorides were obtained in comparatively good yields in chlorobenzene under mild reaction conditions.     

Preparation and thermal properties of polyquinazolones: Effect of the chemical structure of bisbenzoxazinones on the thermal properties

Four kinds of polyquinazolones were synthesized from 4,4′-diaminodiphenylether and bisbenzoxazinones having different central aromatic nuclei (benzene, biphenyl, benzophenone, diphenylmethane). All the polymers were prepared by solution polycondensation at 190°C at a concentration of 15% solid in m-cresol, and were obtained with intrinsic viscosities in the range of 0.3–0.8 dL/g in 97–98% yield. Their thermal properties were studied by using dynamic thermogravimetry and isothermal weight loss. All the polymers were found to produce high char yields (55–75%) in nitrogen. Oxidative thermal stability of the polymers was dependent on the chemical structure of bisbenzoxazinone and was governed by the stability of the bonds in the quinazolone units. The following order of oxidative thermal stability of the quinazolone units was determined from this study: diphenylmethane < benzophenone < biphenyl < benzene.     

Selective Photoinduced Oxidation of Benzylic Methylen Groups through UV Irradiation in Presence of Ferric Chloride

Selective oxidation of benzylic methylene groups through UV irradiation in acetone/water/FeCl₃ mixtures is reported. This method applied to a series of model compounds, provides an easy access to the corresponding 1-oxo derivative. Thus, tetralin gives a 100% yield of 1-tetralone, indane leads to 60% of 1-indanone, and diphenylmethane is oxidized to benzophenone with 80% yield. However, under the same conditions, alkyl-substituted aromatic hydrocarbons such as toluene, ethyl- and propylbenzene lead to low yields of aldehydes or ketones. Isochromane furnishes a mixture of two substances which can be interconverted, namely the expected l-isochromanone (9%) and the corresponding hydroxy acid (23%). We failed to apply the method to nitrogen heterocycles containing benzylic groups such as 1,2,3,4- and 5,6,7,8-tetrahydroquinoline as they do not react due to the formation of complexes which precipitate from the solutions.