The chemistry of Niobium and Tantalum halides, MX5, with haloacetic acids and their related anhydrides: anhydride C–H bond activation promoted by MF5

Niobium and tantalum pentahalides, MX5 (1), react with acetic acid and halo-substituted acetic acids, in 1:1 ratio, to give the dinuclear complexes [MX4(μ-OOCMe)]2 [M = Nb, X = Cl, 2a; M = Ta, X = Cl, 2b; Br, 2c] and [MCl4(μ-OOCR)]2 [M = Nb, R = CH2Cl, 4a; CHCl2, 4c; CCl3, 4e; CF3, 4g; CHBr2, 4i; CH2I, 4j; M = Ta, R = CH2Cl, 4b; CHCl2, 4d; CCl3, 4f; CF3, 4h]. The solid state structures of 2b and 4e have been ascertained by X-ray diffraction studies. The reactions of 1 with acetic anhydride and halo-substituted acetic anhydrides result in C–O bond activation and afford 2 and 4, respectively, with concomitant formation of acetyl halides. Moreover, the complexes MCl5[OC(Cl)Me] [M = Nb, 3a; M = Ta, 3b] have been detected in significant amounts within the mixtures of the reactions of MCl5 with acetic anhydride. TaI5 is unreactive, at room temperature, towards both MeCOOH and (MeCO)2O. MF5 react with RCOOH (R = Me, CH2Cl) in 1:1 molar ratio, to afford the ionic compounds [MF4(RCOOH)2][MF6], 5a–d, in high yields. The additions of (RCO)2O (R = Me, CH2Cl) to MF5 give 5, suggesting that anhydride C–H and C–O bonds activation is operative during the course of these reactions

Activation reactions of 1,1-dialkoxoalkanes and unsaturated O-donors by titanium tetrafluoride

The reactivity of TiF4 with a variety of non cyclic 1,1-dialkoxoalkanes [CH2(OR)(2), R = Me, Et, Me2C(OMe)(2), MeCH(OEt)(2), ClCH2CH(OEt)(2), CH(OMe)(3), PhC CCH(OEt)(2)], 1,3-dioxolane, N2CHCO2Et and 1,2-epoxybutane has been investigated. Activation, including fragmentation and/or rearrangement of the organic moiety, has been observed at room temperature in some cases; it generally occurs unselectively via C-O bond fission and the formation of new C-O, C-H and C-C bonds. Small differences in the structure of the organic substrate may determine significant differences in the reactivity with TiF4

The reactivity of MoCl5 with molecules containing the alcohol functionality

The 1:1 M reaction of MoCl5 with Cl(CH2)2OH, in dichloromethane at room temperature, proceeded with chlorine–oxygen interchange and HCl release to give MoOCl3 in 65% yield. The analogous reactions involving iPrOH, MeOH, L-menthol and H2O gave impure MoOCl3. MoCl5 reacted with Me2N(CH2)2OH in 1:1 M ratio affording the 2-chloroammonium salt [Me2NH(CH2)2Cl]2[Mo2O2Cl8], 1. The reaction of MoCl5 with MeO(CH2)2OH afforded a mixture of [Mo(O(CH2)2OMe)2Cl2][Mo2O2Cl7], 2a, and [Mo(O(CH2)2OMe)2Cl2][MoOCl4], 2b. The products 1, 2a and 2b were characterized by analytical and spectroscopic techniques, and by X-ray diffractometry. The X-ray structure of 2b shows weak anion–anion interactions, therefore 2b might be alternatively viewed as a [Mo2O2Cl8]2- salt

Arene ruthenium (II) complexes with phosphorous ligands as possible anticancer agents

Ruthenium(II) complexes of formula [Ru(?6-arene)Cl2(PTA)] (RAPTA) are potential anticancer drugs with notable antimetastatic and antiangiogenic activity, which are now pointing to clinical trials. Following the great interest aroused by these compounds, a variety of RAPTA derivatives, obtained by chloride substitution and/or containing functionalized arene ligands, and complexes resembling the RAPTA structure but bearing different phosphorous ligands have been synthesized and evaluated for their anticancer activity. An overview of all of these biologically relevant complexes will be given, with particular reference to the anticancer behaviour exhibited by the compounds and the possible relationship with structural aspects

The reactivity of niobium and tantalum pentahalides with imines

The reactivity of NbCl5, NbF5 and TaCl5 with a selection of commercial imines was investigated for the first time by using dichloromethane as reaction medium. NbCl5 reacted with Ph2C=NH, in 1:2 molar ratio, affording [Ph2C=NH2][NbCl5(N=CPh2)], 1, in 55% yield, as result of imine self-protonation. The iminium salt [PhCH=NHtBu][NbCl6], 2, was isolated in 52% yield from NbCl5 and PhCH=NtBu (1:1 molar ratio), while a low yield of [tBu2C=NH2][NbCl6], 3, was identified from NbCl5/tBu2C=NH. The 1:1 reactions of NbF5 with Ph2C=NH and PhCH=NtBu were accompanied by electron interchange and led to the isolation of the salts [Ph2C=NH2][NbF6], 4, and [PhCH=NHtBu][NbF6], 5, respectively, in ca. 50% yields. Few crystals of [Ph2C=NH2]2[Ta2Cl10O], 6, were recovered from TaCl5/Ph2C=NH, the anion being probably generated by the action of adventitious water. Compounds 1-6 were characterized by elemental analysis, IR and NMR spectroscopy. The structures of 1, 4 and 6 were ascertained by X-ray diffraction studies

Ligand-interchange reactions between M(iv) (M = Ti, V) oxide bis-acetylacetonates and halides of high-valent group 4 and 5 metals. A synthetic and electrochemical study

The reactions of M’O(acac)2[M’ = Ti, V; acac = acetylacetonato anion] with equimolar amounts of MF5 (M = Nb, Ta) in CH2Cl2 afforded Ti(acac)2F2, 1a, and [V(acac)3][MF6] (M = Nb,4a;M=Ta,4b), respectively. MOF3 (M = Nb, 2a; M=Ta,2b) were co-produced from MF5/TiO(acac)2. The intermediate species [TaF4{OTi(acac)2}2][TaF6], 3, was intercepted in the course of the formation of 1a from TiO(acac)2/TaF5. NbCl5 reacted with TiO(acac)2 yielding selectively the previously reported [NbO(acac)Cl2]x, 5, and Ti2(acac)2(μ-Cl)2Cl4, 6. Complex 6 was alternatively obtained from the addition of a two-fold excess of TiCl4 to VO(acac)2. The 1 : 1 reactions of TiX4 (X = F, Cl) with TiO(acac)2 in dichloromethane gave Ti(acac)2X2 (X = F,1a; X = Cl, 1b) and TiOX2 (X = F, 7a; X = Cl, 7b). The 1 : 1 combination of TiX4 (X = F, Cl) with VO(acac)2 led to 1a, band VOX2 (X = F, 8a; X = Cl, 8b). The μ-oxido compounds (C6F5)3B–O–M’(acac)2(M’ = Ti, V) underwent fragmentation by [PF6]- in chlorinated solvent, yielding POF3, 9, and [B(C6F5)3F]-, 10, according to NMR studies; 1a and V(acac)3+, respectively, were detected as the metal-containing species. Electrochemical studies were carried out aiming at the full characterization of the products and the observation of possible degradation pathways

Carbon???Carbon Bond Coupling of Vinyl Molecules with an Allenyl Ligand at a Diruthenium Complex

The room-temperature reactions of the diruthenium μ-allenyl complex [Ru2Cp2(CO)2(NCMe){μ-η1:η2-CH═C═CMe2}]BF4, 3-NCMe, with a series of alkenes, RCH═CH2, afforded the complexes [Ru2Cp2(CO)2{μ-η3:η2-CH(R)CHC(Me)C(Me)CH2}]BF4(R═Ph, 4; 4-C6H4Me, 5; Me, 6; nBu, 7; CO2Me, 8; and H, 9), containing an uncommon pentacarbon alkenyl-allyl ligand. Cross experiments with deuterated reagents, i.e., [Ru2Cp2(CO)2(NCMe){μ-η1:η2-CD═C═CMe2}]BF4(3b-NCMe) and CD2═CD(C6H5) (styrene-d3), revealed that the formation of 4-9 is initiated by an attack of the alkene to the central carbon of the allenyl moiety, triggering two distinct C-H activation processes. Compounds 4-9 were characterized by analytical and spectroscopic methods and by single-crystal X-ray diffraction in the cases of 4, 7, and 8. Reported here is the clean coupling on a metallic scaffold between two C2and C3functions invoked in Fischer-Tropsch mechanistic models

A Crystallographic and Spectroscopic Study of the Reactions of WCl6 with Carbonyl Compounds

WCl6, 1, reacted with two equivalents of HC(O)NR2 (R = Me, Et) in CH2Cl2 to afford the W(VI) oxo-derivatives WOCl4(OCHNR2) (R = Me, 2a; R = Et, 2b) as main products. The hexachlorotungstate(V) salts [{ }2(-H)][WCl6], 3, and [PhNHC(Me)N(Ph)C(O)Me][WCl6], 4, were isolated in moderate yields from the 1:2 molar reactions of 1 with N-methyl-2-pyrrolidone (in CH2Cl2) and acetanilide (in CDCl3), respectively. The additions of two equivalents of ketones/aldehydes to 1/CH2Cl2 yielded the complexes WOCl4[OC(R)(R’)] (R = Me, R′ = Ph, 5a; R = R’ = Ph, 5b; R = R’ = Me, 5c; R = R’ = Et, 5d; R = H, R’ = 2-Me-C6H4, 5e) and equimolar amounts of C(R)(R’)Cl2. Analogously, WOCl3[2-{1,2-C6H4(O)(CHO)}], 5f, and 1,2-C6H4(OH)(CHCl2) were obtained from 1 and salicylaldehyde. The 1:1 reaction of 1 with acetone in CH2Cl2 resulted in the clean formation of WOCl4 and 2,2-dichloropropane. Compounds 5a,b,f were isolated as crystalline solids, whereas 5c,d,e could be detected by solution NMR only. The interaction of 1/CH2Cl2 with isatin, in 1:1 molar ratio, revealed to be a new, convenient route for the synthesis of 3,3-dichloro-2,3-dihydro-1H-indol-2-one, 6. The 1:1 reactions of 1 with R’OCH(R)CO2Me (R = H, R’ = Me; R = Me, R’ = H) in chlorinated solvent afforded the tungsten(V) adducts WCl4[2-OCH(R)CO2Me] (R = H, 7a; R = Me, 7b). 1/CH2Cl2 reacted sluggishly with equimolar quantities of trans-(CO2Et)CH=CH(CO2Et) and CH2(CO2Me)2 to give, respectively, the W(IV) derivatives WCl4[2-CH2(CO2Me)2], 8a, and [WCl4-2-{trans-(CO2Et)CH=CH (CO2Et)}]n, 8b, in about 70% yields. The molecular structures of 2a, 3, 4, 5a, 5f, 7a and 7b were ascertained by X-ray diffraction studies

The versatile chemistry of niobium pentachloride with aliphatic amines: Aminolysis, metal reduction and C–H activation

The reactions of NbCl5 with limited amounts (1-2 molar equivalents) of a series of primary, secondary and tertiary amines were investigated in dichloromethane as solvent. The 1:1 reaction of NbCl5 with NHEt2 cleanly afforded an equimolar mixture of [NbCl4(NEt2)]2, 1, and [NH2Et2][NbCl6], 2a; the former product constitutes the first example of structurally characterized Nb(V) chlorido-amido complex. The ammonium salts [NH3nPr][NbCl6], 2b, and [NH2iPr2][NbCl6], 2c, were isolated in 20-30% yields from the 1:1 reactions of NbCl5 with NH2nPr and NHiPr2, respectively. Cα-H bond activation and Nb(V) to Nb(IV) reduction took place in the reactions of NbCl5 with NR3 (R = Bz, Et; Bz = CH2Ph). The iminium salt [(PhCH2)2N=CHPh][NbCl6], 3, and the ammonium ion [NH(CH2Ph)3]+ were identified as the prevalent species generated from the 1:1 NbCl5/NBz3 interaction. [NHEt3][NbCl6], 4, and [NHEt3]2[NbCl6], 5, were isolated in moderate yields from, respectively, the 1:1 and 1:2 molar reactions of NbCl5 with NEt3. The solid state structures of 1, 2a, 3, 4 and 5 were ascertained by single crystal X-ray studies

Разработка ПО для улучшения качества видео с помощью алгоритмов нейронных сетей

Целью работы является создание программного обеспечения, позволяющего повысить качество видеоматериала. Для достижения цели потребуется выполнить следующие задачи: 1.Выделить критерии качества видеоизображения; 2.Рассмотреть современные алгоритмы нейронных сетей, позволяющих улучшить выбранные критерии; 3.Реализовать программное обеспечение для повышения качества выбранных критериев. В ходе выполнения работы создано приложение, позволяющее увеличить качество видеоматериала. Результаты данной работы могут быть использованы в сфере видеопроизводства.The purpose of the work is to create software to improve the quality of video material. To achieve the purpose, it will need to perform the following tasks: 1. Select video quality criteria; 2. To consider modern algorithms of neural networks that improve the selected criteria; 3. Implement software to improve the quality of selected criteria. In the course of the work, an application was created to increase the quality of video material. The results of this work can be used in the field of video production