Reaction Of Cis Research Articles

Reactivity of cis-[RuCl 2(TMSO) 4] towards carbon monoxide: synthesis, structure, and reactivity of tetramethylene sulfoxide complexes [RuCl 2(CO) x(TMSO) 4− x] ( x=1–3)

The reactivity of cis-[RuCl 2(TMSO) 4] (TMSO=tetramethylene sulfoxide) towards carbon monoxide has been systematically investigated. The reaction of cis-[RuCl 2(TMSO) 4] with CO at various temperatures and ambient pressure leads to substitution of either one, two, or three TMSO ligands with CO, depending on the choice of reaction conditions. Thus, we have been able to isolate cis-[RuCl 2(TMSO) 3(CO)] ( 1), cis-[RuCl 2(TMSO) 2(CO) 2] ( 2), and fac-[RuCl 2(TMSO)(CO) 3] ( 3). Crystal of 1 is colorless, orthorhombic, space group Pca2 1, a=18.4574(2) Å, b=8.2509(3) Å, c=12.5757(4) Å. Crystal of 2 is yellow, triclinic, space group P 1 ̄ , a=8.4480(10) Å, b=9.223(2) Å, c=10.768(2) Å, α=74.157(7)°, β=73.399(7)°, γ=83.775(8)°. Crystal of 3 is a colorless prism, monoclinic, space group P2 1/ n, a=10.134(5) Å, b=9.056(4) Å, c=13.274(9) Å, β=100.67(2)°. These complexes represent the first example of well-characterized Ru(II)-chloride-TMSO-carbonyl complexes. The most salient feature is that substitution of more than one TMSO ligand with carbon monoxide induces the selective isomerization of TMSO mutually trans to it from S- to O-bonding TMSO ( 2 and 3). However, in contrast to Ru(II, III)-chloro-DMSO-carbonyl and Ru(III)-chloro-TMSO-carbonyl complexes, no isomerization was observed on coordination of carbon monoxide in compound 1. Complex 1 is the versatile precursor for the synthesis of Ru(II)CO species in which TMSO ligands are partially or entirely replaced by N-donor ligands. Reaction of 1 with pyridine produces two different compounds, trans-[RuCl 2(TMSO)(CO)(py) 2] ( 4) and trans-[RuCl 2(py) 4] ( 5). The crystal of 4 is yellow, monoclinic, space group C2/ c, a=12.807(2) Å, b=10.561(2) Å, c=25.809(5) Å, β=94.320(6)°. Attempted reaction of 1 with TMSO resulted in no new compound.

Synthesis of a Water Soluble, Monosubstituted C60 Polymeric Derivative and Its Photoconductive Properties

Atom transfer radical polymerization (ATRP) catalyzed by N,N‘,N‘,N‘ ‘,N‘ ‘-pentamethyldiethylenetriamine (PMDETA)/CuBr was performed to synthesize poly(tert-butyl acrylate) with predictable molecular weight, low polydispersities, and well-defined bromine end groups. The bromine end groups have been substituted by azides. Then C60 end-capped poly(tert-butyl acrylate) was synthesized by the reaction of C60 with PtBA−N3 in DMF. GPC measurement showed that C60 was chemically bonded to the end chain of poly(tert-butyl acrylate); i.e., the final products (PtBA−C60) were monosubstituted. 1H NMR, FTIR, and UV−vis measurements confirmed that the water-soluble, monosubstituted C60 derivatives of poly(acrylic acid) (PAA−C60) have been obtained by hydrolysis of PtBA−C60. The photoconductivities of PtBA−C60 and PAA−C60 were measured by photoinduced xerographic discharge technique. Experimental results showed that C60 bonded in the polymers is the headstream of the photoconductivity, and an increase of the C60 content ...

Reactivity of Functionally Substituted Azoles Towards Electrophiles. Novel Synthesis of Thienylazoles and Phenylazoles.

Abstract Phenacyl bromide reacted with imidazole 1a and 1,2,4-triazole 1b to yield the respective azolylacetophenones 1c,d. These reacted with phenyl isothiocyanate and phenacyl bromide yielding thienylazoles 4a,b. Reaction of 1c,d with dimethylformamide dimethylacetal followed by treating of the product with thiourea afforded the azolylpyrimidines 10a,b. Azolylpyrans 8a,b were obtained from reaction of 1c,d with acrylonitrile. The reaction of azoles 1a,b with chloroacetylacetone in acetone solution in the presence of base afforded the phenylazoles 13a,b.

Selective Reduction of Fullerene C60 by Metals in Neutral and Alkaline Media. Interaction of C60 with KOH

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reactivity of Functionally Substituted Azoles Towards Electrophiles. Novel Synthesis of Thienylazoles and Phenylazoles

Phenacyl bromide reacted with imidazole 1a and 1,2,4-triazole 1b to yield the respective azolylacetophenones 1c,d. These reacted with phenyl isothiocyanate and phenacyl bromide yielding thienylazoles 4a,b. Reaction of 1c,d with dimethylformamide dimethylacetal followed by treating of the product with thiourea afforded the azolylpyrimidines 10a,b. Azolylpyrans 8a,b were obtained from reaction of 1c,d with acrylonitrile. The reaction of azoles 1a,b with chloroacetylacetone in acetone solution in the presence of base afforded the phenylazoles 13a,b.

Preparation and characterization of rhodium(iii), iridium(iii) and ruthenium(ii) bearing 1,3- or 1,4-dithianesElectronic supplementary information (ESI) available: Crystal data and ORTEP figures for 2b, 2ab and 3c and further experimental details. See http://www.rsc.org/suppdata/dt/b3/b306496d/

Reactions of [Cp*MCl2]2 (1a: M = Rh, 1b: M = Ir) or [(arene)RuCl2]2 (1c: arene = p-cymene; 1d: arene = C6Me6) with 1,3-dithiane (1,3-S2C4H8) gave [{LMCl2}2(1,3-S2C4H8)] 2 and [(LMCl2)( 1,3-S2C4H8)] 3 (LM = Cp*Rh, Cp*Ir, or (p-cymene)Ru, (C6Me6)Ru), depending on molar ratios between 1 and 1,3-dithiane. The reaction in the presence of KPF6 afforded the corresponding ionic complexes [LMCl(1,3-S2C4H8)2](PF6) 4. Complex 3a was treated with 1b, affording the heterobinuclear complex [Cp*RhCl2(1,3-S2C4H8)IrCl2Cp*] 2ab. Complex 2ab was obtained by a similar reaction of 3b with 1a, whereas reactions of 1c with 3a or 3b gave homonuclear complexes 2c and 2a (or 2b). Ionic complexes 4 were treated with 1, generating homo- or hetero-trinuclear complexes [{LMCl(1,3-S2C4H8)2}(L′MCl2)2](PF6) 5 (LM = Cp*Ir, L′M = Cp*Rh, Cp*Ir, or (p-cymene)Ru: LM = Cp*Rh, L′M = (p-cymene)Ru). Reactions of 1 with 1,4-dithiane (1,4-S2C4H8) were carried out in a 1 ∶ 1 molar ratio, generating binuclear complexes [(Cp*MCl2)2(1,4-S2C4H8)] (6a: M = Rh; 6b: M = Ir) or [{(arene)RuCl2}2(1,4-S2C4H8)] (arene = p-cymene (6c), C6Me6 (6d)). Reaction of 1a with an excess of 1,4-dithiane afforded a neutral mononuclear complex [Cp*RhCl2(1,4-S2C4H8)] 7a, whereas the reactions of 1b or 1c generated the corresponding ionic complexes [Cp*IrCl(1,4-S2C4H8)](Cl) 8b and [(p-cymene)RuCl(1,4-S2C4H8)](Cl) 8c. Treatment in the presence of KPF6 gave ionic complexes [LM(1,4-S2C4H8)](PF6) (LM = Cp*Rh (9a), Cp*Ir (9b), (p-cymene)Ru (9c)) Structures of 2a, 2ab, 3a, 3c, 4a, 8b and 9c were confirmed by X-ray analyses.

Study of the Reactivity of 2-Acetyl-, 2-Cyano-, 2-Formyl-, and 2-Vinylphenyl Palladium(II) Complexes. Mono- and Triinsertion of an Isocyanide into the Pd−C Bond. A 2-Cyanophenyl Palladium Complex as a Ligand

We have studied the reactivity of the complexes [Pd(C6H4X-2)Br(bpy)] (bpy = 2,2‘-bipyridine; X = C(O)Me (1a), CN (1b), CHO (1c)), [Pd{C6H4CHCH2-2}(PPh3)(bpy)](TfO) (TfO = CF3SO3; 2d), trans-[Pd(C6H4X-2)Br(PPh3)2] (X = C(O)Me (3a), CN (3b), CHCH2 (3d)), and [Pd(μ-Br)(C6H4X-2)(PPh3)]2(X = C(O)Me (4a), CN (4b)). Their reactions with XyNC (Xy = 2,6-dimethylphenyl) depend on the nature of X and the other ligands and on the reaction conditions. The products of these reactions are mono- and triinserted complexes. Among the former are [Pd{C(NXy)C6H4X-2}Br(L2)] (L2 = bpy, X = C(O)Me (5a), CN (5b); L = CNXy, X = C(O)Me (6a), CN (6b), CHCH2 (6d)) and trans-[Pd{C(NXy)C6H4CHCH2-2}(CNXy)2(PPh3)](TfO) (7d). The reaction of 1c with XyNC (1:5 molar ratio) gives 10, a product resulting after substitution of bpy, coordination of two molecules of XyNC, triinsertion of XyNC, and a cyclization resulting after the attack of the nitrogen of the first inserted molecule at the carbon atom of the formyl group. The complexes [Pd{κ2C...

Synthesis of [1,3]dithiole and spiro[1,3]dithiole thiopyran derivatives of the [1,2]dithiolo[1,4]thiazine ring system.

We report the synthesis of some new polysulfur-nitrogen heterocycles by cycloaddition reactions to readily available tricyclic condensed 1,2-dithiole-3-thiones. Thus, treatment of bis[1,2]dithiolopyrrole ketothione 1 with diacyl acetylenes gave the bis-aducts 2a-d. On the other hand, cycloaddition of bis[1,2]dithiolo[1,4]thiazine ketothione 3 with 1 equiv of acyl or diacyl acetylenes gave [1,3]dithiolylidenyl[1,2]dithiolo[1,4]thiazines 4a-f in fair to high yields. Catalysis by scandium triflate was used in the reactions that implied the less reactive dipolarophiles. Treatment of 3 with 2 equiv of DBA gave the bis-aduct 5a, and reaction of 4c with DMAD gave the mixed bis-adduct 5b. Cyclic voltammetry of selected examples showed irreversible processes that were influenced by the electrochemical activity of peripheral groups bonded to the heterocyclic system.

Synthesis, X-ray structure, and properties of the singly bonded C60 dimer having diethoxyphosphorylmethyl groups utilizing the chemistry of C60(2-).

[reaction: see text] A singly bonded C60 dimer having a diethoxyphosphorylmethyl group on each C60 cage was obtained by the reaction of C60(2-) dianion with diethyl iodomethylphosphonate followed by the treatment with iodine. The precise structure of the dimer was determined for the first time by X-ray crystallography, and its homolytic dissociation as well as spectroscopic and electrochemical properties were clarified.

Substrate specificity of thermostable farnesyl diphosphate synthase with respect to 4-alkyl group homologs of isopentenyl diphosphate

In order to investigate substrate spcificity of Bacillus stearothermophilus farnesyl diphosphate synthase (FPS), we examined the reactivity of 4-alkyl group homologs of isopentenyl diphosphate (IPP). The enzymatic reactions of the 4-methyl homologs, ( E)-3-methylpent-3-enyl diphophates ( 1a) and ( Z)-3-methylpent-3-enyl diphophates ( 1b) with geranyl diphosphate (GPP) gave 4-methylfarnesyl diphosphates ( 2a and 2b), respectively. The stereochemistry of each aldehyde derived from 2a or 2b was determined by CD spectrometry to be ( S)-4-methylfarnesal or ( R)-4-methylfarnesal, respectively. Similarly, 1a reacted with dimethylallyl diphosphate (DMAPP) to give a mixture of (4 S)-4-methylgeranyl diphosphates ( 3a) and (4 S,8 S)-4,8-dimethylfarnesyl diphosphates ( 4a). The ( Z)-isomer 1b also reacted with DMAPP to give the corresponding enantiomers with (4 R)- and (4 R,8 R)-configurations. On the other hand, reactions of the 4-ethyl homologs, ( E)-3-methylhex-3-enyl diphosphates ( 1c) and ( Z)-3-methylhex-3-enyl diphosphates ( 1d) with GPP gave two types of 4-ethylfarnesyl diphosphates. Reactions of 1c or 1d with DMAPP also gave two types of 4-ethylgeranyl- and 4,8-diethylfarnesyl diphosphates. Meanwhile, reaction of the 4-propyl homologs, ( E)-3-methylhept-3-enyl diphosphates ( 1e) and ( Z)-3-methylhept-3-enyl diphosphates ( 1f) with GPP gave two types of 4-propylfarnesyl diphosphates. Reactions of 1e or 1f with DMAPP gave only two types of the 4-propyl GPPs. However, neither ( E)-3-methyloct-3-enyl diphosphates ( 1g) or ( Z)-3-methyloct-3-enyl diphosphates ( 1h), nor ( E)-4-bromo-3-methylbut-3-enyl diphosphate ( 1i) or ( Z)-4-bromo-3-methylbut-3-enyl diphosphate ( 1j) was acceptable as a substrate for the thermophilic FPS at all.

The oxidation of fullerenes (C60, C70) with various oxidants under ultrasonication

The reaction of C60, under ultrasonication, with various oxidants, such as 3-chloroperoxy benzoic acid (Fluka 99%), 4-methyl morpholine N-oxide (Aldrich 97%), chromium (VI) oxide (Aldrich 99.9%), and the oxone® monopersulfate compound, causes the oxidation of fullerenes at room temperature. The FAB-MS spectra and HPLC profile confirmed that the products of fullerene oxidation were [C60(O)n] (n=1∼3 or n=1). C70 also reacted, under ultrasonication, with various oxidants, but the reaction rate of C70 was lower than that of C60.

Selective reduction of fullerene C60 by metals in neutral and alkaline media. Interaction of C60 with KOH

The reduction of fullerene C60 by Zn and Mg in DMF was studied both in the presence and absence of KOH. Fullerene C60 was reduced in these systems to form the C60 n– (n = 1, 2, and 3) anions. The anions were detected by optical and ESR spectroscopies. It was found that Mg reduced C60 to the monoanion, Mg/KOH and Zn reduced C60 to the dianion, and Zn/KOH reduced C60 to the trianion. Like KCN, potassium hydroxide adds to fullerene upon interaction with C60 in DMF. The reaction of C60 with KOH in benzonitrile was accompanied by the generation of the fullerene monoanion. A possible mechanism of the formation of fullerene monoanions in the presence of KOH is discussed. The degradation of the C60 n– anions in air was studied.

Absolute stereochemistry of chiral C60 fullerene bis-adducts.

To determine the absolute configuration of chiral fullerene bis-adducts, we have studied the double Bingel reaction of C60 with chiral tether (2S,3S)-(-)-9 derived from (R,R)-(+)-tartaric acid, and have succeeded in isolating two possible chiral bis-adducts 10a (5%) and 10b (2%) in addition to the Cs-symmetrically added derivative 10c (40%). The CD spectra of chiral bis-adducts [CD(+)281]-10a and [CD(-)281]-10b show very intense Cotton effects, which are almost of mirror image, indicating that their chiral C60 pi-electron systems are enantiomeric each other. The 1H and 13C NMR spectra of 10a and 10b indicate that they have C2-symmetrical structures, and the vicinal coupling constants between two equivalent protons H-2 and H-2' were determined as 1.2 Hz for 10a and 1.8 Hz for 10b, respectively by the 13C satellite band method. From the conformational analyses, the absolute configurations of these chiral C60 fullerene bis-adducts were unambiguously determined as [CD(+)281]-(S,S,fC)-10a and [CD(-)281]-(S,S,fA)-10b, respectively.

Gas-Phase Ion—molecule Reactions of C60 with the Plasma of Methyl Acrylate

The gas-phase ion–molecule reactions of C60 with the plasma generated from methyl acrylate under self-chemical ionization conditions were studied by use of a triple-quadrupole mass spectrometer. The adduct cation [C60C3H3O]+ and protonated molecular ion [C60H]+ were observed as the major product ions. The former adduct ion is formed by electrophilic reaction of C60 with the ion [CH2=CHCO]+, a main fragment ion resulting from the methyl acrylate molecular ion [CH2=CHCOOCH3]+ through alpha cleavage. The latter ion is generated by proton transfer from protonated methyl acrylate to C60. Semi-empirical quantum chemical calculations have been performed for the eight possible isomers of [C60C3H3O]+ at the Hartree–Fock level by use of the AM1 method. The results show three types of cycloadducts as the most stable structures among the possible isomers.

Fe(II)-mediated fragmentation of 1,4-diaryl-2,3-dioxabicyclo[2.2.2]octanes through competitive single electron transfer pathway and Lewis acid pathway

Reactions of 1,4-diaryl-2,3-dioxabicyclo[2.2.2]octanes 1a– d ( 1a : Ar= p-FC 6H 4, 1b : Ar=Ph, 1c : Ar= p-MeC 6H 4, 1d : Ar= p-MeOC 6H 4) with FeBr 2 in THF afforded 1,4-diarylbutan-1,4-diones 2a– d and 1,4-diaryl-7-oxabicyclo[2.2.1]heptanes 3a– d . On the other hand, 4-aryl-3-cyclohexenones 4c– d and p-substituted phenols 5c– d were obtained in the reactions of 1c– d with FeBr 2 in CH 2Cl 2. A new fragmentation mechanism involving an electrophilic oxyl radical 1,5-substitution and a nucleophilic O-1,2-aryl shift is proposed based on the product analysis. In addition, the in vitro antimalarial activities of 1a– d were tested.

Alkali metal reduction of 2-halogeno- and 2-thiolato-2,3-dihydro-1H-1,3,2-diazaboroles

The reduction of 2-bromo-1,3,2-diazaborole tBuNCHCH(tBu)BBr (4c) with a potassium mirror in 1,2-dimethoxyethane afforded a non-separable 1 ∶ 2 ∶ 1 mixture of the compounds tBuNCHCHN(tBu)BH (5), tBuNCHCHN(tBu)BOCH3 (6) and {tBuNCHCHN(tBu)B}2O (7). Reaction of 4c with a potassium–sodium alloy in N,N,N′,N′-tetramethylethylenediamine led to 5 as the major product. 1,3,2-Diazaboroles tBuNCHCHN(tBu)BNMe2 (8) and {tBuNCHCHN(tBu)B}2 (9) were spectroscopically identified as minor products. The treatment of 4c with potassium–sodium alloy in toluene solution in the presence of [15]crown-5 yielded a 1 ∶ 1 mixture of 5 and the benzyl derivative tBuNCHCHN(tBu)BCH2Ph (12). The same reaction in toluene-d8 produced the deuterated species 5-d1 and 12-d7. tBuNCHCHN(tBu)BCH3 (17) and 1,4-diazabutadiene (tBuNCH)2 (18) resulted from the treatment of tBuNCHCHN(tBu)BSCH3 (15) with potassium–sodium alloy in n-hexane. In contrast to this, compound 9 was obtained as the main product of the reduction of tBuNCHCHN(tBu)BStBu (16) under similar conditions. The reduction of the 1-bromo-2-tert-butyl-1,2-dihydro[1,3,2]diazaborolo[1,5-a]pyridine (19) smoothly produced the respective diborane(4) derivative (20) which was subjected to X-ray diffraction analysis.

Synthesis of 1,2-Dihydro-1,2-azaborines and Their Conversion to Tricarbonyl Chromium and Molybdenum Complexes

1,2-Dihydro-1,2-azaborines (1c, 1d, and 1e) have been prepared by the reaction of the corresponding 2,3-dihydro-1H-1,2-azaborol-3-yllithium reagents (1c, 1d, and 1e). The reaction of 1e with Py3Mo(CO)3 and BF3·OEt2 affords Mo(CO)3 complex 5e, while the reaction of 1c with Cr(CH3CN)3(CO)3 affords Cr(CO)3 complex 6c. X-ray structures of 5e and 6c show that the metals are η6-bound to the 1,2-dihydro-1,2-azaborine rings.

1-Substituted 3-dimethylaminoprop-2-en-1-ones as building blocks in heterocyclic synthesis: New routes to 6-aroylpyridazin-3-ones, 4,6-diaroylpyridazin-3-imines and 3-aroylpyrazolo[5,1-c][1,2,4]triazines

The Wittig reaction of 3-aryl/heteroaryl-2-arylhydrazono-3-oxopropanals 2c,d with ethyl triphenylphosphonioacetate in the presence of methanesulfinylmethyl carbanion affords 2-substituted 6-aroylpyridazin-3(2H)-ones (5a,b) in moderate yields. Compounds 5a,b were also obtained from the reaction of 2c,d with acetic anhydride in presence of potassium acetate. 1-Substituted-3-dimethylaminoprop-2-ene-1-ones 1b,d couple with 5-methylisoxazole-3-diazonium chloride to yield isoxazolylhydrazonopropanals 2g,h. Compounds 1a,b couple with 5-methylpyrazole-3-diazonium chloride to yield pyrazolylhydrazonopropanals that readily cyclise to the corresponding pyrazolo[5,1-c][1,2,4]triazines. The reactivity of 2-arylhydrazono-3-oxopropanals 2a–f towards a variety of active methylene reagents was investigated.

Synthesis and Characterization of μ3-η2,η2,η2-C60 Trirhenium Hydrido Cluster Complexes

The reaction of C60 with Re3(μ-H)3(CO)11(NCMe) in refluxing chlorobenzene produces Re3(μ-H)3(CO)9(μ3-η2,η2,η2-C60) (1) in 50% yield. Initial decarbonylation of 1 with Me3NO/MeCN followed by reactio...

RAPID ASSESSMENT OF THE FREE RADICAL SCAVENGING PROPERTY OF FULLERENES

The free radical scavenging property of fullerenes and their derivatives is demonstrated by a facile color reaction of C60 with the 1,1-diphenyl-2-picryl hydrazyl radical. A rapid test by simply monitoring the reaction using ultraviolet-visible spectroscopy is suggested.