1,4-Diazabuta-1,3-dien-N-Sulfinylamin-Nickel(0)-Komplexe

1,4-Diazabuta-1,3-Diene-N-Sulfinylamin Nickel(0) Complexes Synthesis, properties, and reactions of 1,4-diazabuta-1,3-diene-N-sulfinylamine nickel(0) complexes are described. The highly coloured and extremely air and moisture sensitive nickel(0) complexes have been characterized by means of i.r. and ¹H n.m.r.spectroscopy. The N-sulfinylamine ligands are η²-(S,N)-side on coordinated.     

Electrooxdation of Tricarbonyl(N,N-Diphenylcyclohexadienecarboxamide)Iron Complexes. Reversibility of Electron Transfer and Free Energy Change

Qualitative and quantitative criteria of irreversibility of electron transfer in cyclic voltammetry (CV) of tricarbonyl(N,N-diphenylcyclohexadienecarboxamide)iron complexes were investigated. The measurement of the heterogeneous rate constants for electron transfer according to CV data over an extended range of free energy change ( ΔG) for these complexes are described. Kinetic analyses of the electrochemical technique demonstrates that when the applied potential exceeds the standard potential E°, the experimental rate constant k_e represents an accurate measurement of the intrinsic rate constant k₁ for electron transfer. However, as the applied potential is less than E°, the reversibility of the electron-transfer process becomes increasingly more important, and the rate constants for reverse electron transfer k_-t and decomposition k₂ of the electrogenerated intermediate have to be taken into account.     

Expanding the Chemical Space of Tetracyanobuta-1,3-diene (TCBD) through a Cyano-Diels-Alder Reaction: Synthesis,Structure, and Physicochemical Properties of an Anthryl-fused-TCBD Derivative

Tetracyanobuta-1,3-diene (TCBD) is a powerful and versatile electron-acceptor moiety widely used for the preparation of electroactive conjugates. While many reports addressing its electron-accepting capability have appeared in the literature, significantly scarcer are those dealing with its chemical modification, a relevant topic which allows to broaden the chemical space of this interesting functional unit. Here, we report on the first example of a high-yielding cyano-Diels-Alder (CDA) reaction between TCBD, that is, where a nitrile group acts as a dienophile, and an anthryl moiety, that is, acting as a diene. The resulting anthryl-fused-TCBD derivative, which structure was unambiguously identified by X-ray diffraction, shows high thermal stability, remarkable electron-accepting capability, and interesting electronic ground- and excited-state features, as characterized by a thorough theoretical, electrochemical, and photophysical investigation. Moreover, a detailed kinetic analysis of the intramolecular CDA reaction transforming the anthryl-TCBD-based reactant into the anthryl-fused-TCBD product was carried out at different temperatures.     

Predictive abilities of scaled quantum-mechanical molecular force fields: application to 2-methylbuta-1,3-diene (isoprene)

The ab initio-based, scaled quantum-mechanical molecular force field (SQM-FF) analysis of the vibrational spectra of the s-trans and s-gauche conformers of 2-methylbuta-1,3-diene (isoprene), reported previously at the HF/6-31G//HF/6-31G computational level [Bock, et al. J Mol Struct 160: 337, 1987], has been updated in this article using a more complete set of experimental data on the s-gauche conformer along with revised results for the s-trans conformer obtained in the gas phase, in a low-temperature matrix, and in neat crystals. Geometrical parameters and the calculated wavenumbers derived from the SQM-FF at the MP2(FC)/aug-cc-pVDZ//MP2(FC)/aug-cc-pVDZ level are compared to experiment. The analyses performed are consistent with the presence of a twisted high-energy s-gauche conformer of isoprene.     

Reaction of Tricarbonyl(η3-allyl)iron(0) Anions with Bromine

The addition of reactive carbanions to tricarbonyl(η⁴-1,3-diene)iron(0) complexes proceeded at 23°C to give putative tricarbonyl(η³-allyl)iron(0) anion complexes. Trapping of the reactive intermediates with bromine produced nucleophilic-substituted tricarbonyl(η⁴-1,3-diene)iron(0) complexes.     

Synthesis of Drim-7,9(11)-diene and Its Hydroxylated Derivatives

This article describes a new efficient synthesis of drim-7,9(11)-diene and its hydroxylated derivates from drim-8-en-7-one. Reduction of this ketone with NaBO₄ in the presence of CeCl₃ · 7H₂O afforded regio- and stereoselectively drim-8-en-7β-ol in a high yield. Its dehydration with H₂SO₄ under mild conditions led to drim-7,9(11)-diene. Noncatalytic oxidation of drim-7,9(11)-diene with OsO₄ and the catalytic oxidation with the pair OsO₄–NMO gave, in a high yield, depending on conditions, driman-7β,8β,9α,11-tetraol or its mixture with drim-7-en-9α,11-diol and drim-9(11)-en-7α,8α-diol. Under optimal conditions the total yield of these diols reached 89%. The separate, noncatalytic oxidation of drim-7-en-9α,11-diol and of drim-9(11)-en-7α,8α-diol with OsO₄ afforded driman-7α,8α,9α,11-tetraol.     

NBO,NMR Analysis,and Hybrid DFT Study of Structural and Configurational Properties of Di-tert-butyl-, bis(trimethysilyl)-, Bis(trimethgermyl)-, and Bis(trimethylstannyl)- cyclopenta-1,3-dienes

Abstract

The alkyl 1,2-shift in di-tert-butylcyclopenta-1,3-diene (1) and the metallotropic 1,2-shifts in bis(trimethylsilyl)cyclopenta-1,3-diene (2), bis(trimethylgermyl)cyclopenta-1,3-diene (3), and bis(trimethylstannyl)cyclopenta-1,3-diene (4) have been investigated by means of natural bond orbital (NBO), nuclear magnetic resonance (NMR) analysis, and hybrid density functional theory based methods. The B3LYP/DZVP results showed that the M(CH₃)₃ group [M = C (1), Si (2), Ge (3), and Sn (4)] migration barrier heights around cyclopentadienyl rings decrease from di-tert-butylcyclopenta-1,3-diene to its stannane derivative. Also, based on the results obtained, the stabilities of the 5,5-isomers in comparison to the 1,5- and 2,5-isomers increase from di-tert-butylcyclopenta-1,3-diene to its stannane derivative. The results suggest that in these compounds the metallotropic shifts are controlled by the stabilization energies associated with σ→π* electron delocalizations and the increase of the σ_C5-M→π*_C1-C2 electron delocalizations facilitates the M(CH₃)₃ group migrations around cyclopentadienyl rings. Based on the aromatic stabilization energy (ASE) values calculated, the aromaticity increases from the 5,5-isomers of di-tert-butylcyclopenta-1,3-diene to its stannane derivative but the variation of the nucleus-independent chemical shift, NICS(0) and NICS(1), values calculated are not in accordance with the ASE values calculated and the σ_C5-M→π*_C1-C2

electron delocalizations. The correlations between the sigmatropic shift barrier heights, σ→π* electron delocalizations, ASE, and NICS values were investigated.

GRAPHICAL ABSTRACT     

Predictive abilities of scaled quantum mechanical molecular force fields: application to 2,3-dimethylbuta-1,3-diene

In connection with the appearance of new experimental vibrational data on the high-energy rotational isomer of 2,3-dimethylbuta-1,3-diene (I) in a low-temperature matrix and in neat crystals, the ab initio-based vibrational analysis of this molecule has been re-evaluated. Calculated wavenumbers derived from a scaled quantum-mechanical force field analysis at the MP2(FC)/aug-cc-pVDZ//MP2(FC)/aug-cc-pVDZ computational level are compared with experimental data. Several reassignments of the fundamental wavenumbers for I have been suggested in the course of the current analysis, and the existence of a high-energy non-planar s-gauche conformer of 2,3-dimethylbuta-1,3-diene has been confirmed.     

Synthesis of new 1,3-bis（phenylethynyl）disilazanes

Three new 1,3-bis(phenylethynyl)disilazanes were synthesized from the reaction of 1,3-dichlorodisilazanes with (phenylethy- nyl)lithium,and characterized by infrared (IR) spectra,nuclear magnetic resonance (NMR) and mass spectrometry (MS).     

Preparation of 4-trifluoroethylidene-1,3-dioxolane derivatives via new stable (trifluoromethyl)ethynylation reagent

Perfluoroalkylated 4-trifluoroethylidene-1,3-dioxolane derivatives 2a-q were prepared in excellent yields from the reaction of new stable (trifluoromethyl)ethynylation reagent 1a with 1.3 equiv. of TBAF at −15°C for 10 min, followed by treatment with 2 equiv. of phenyl perfluoroalkylated ketone derivatives at room temperature. The reaction of 1a with 1.3 equiv. of TBAF, followed by treatment with 1 equiv. of aldehyde or ketone at −15°C for 10 min and then with trifluoroacetophenone (1 equiv.) at room temperature afforded perfluoroalkylated 4-trifluoroethylidene-1,3-dioxolane derivatives 2t-u in moderate yields.     

A Convenient and Efficient Route to 1,4-Bis（heteroaryl）-buta-1,3-diene and 4-Heteroarylbut-1-en-3-yne from 1,4-Dichlorobut-2-yne

A convenient and practical route to functionalized conjugated 1,3-enynes and 1,3-dienes is described. 1,4-Bis（heteroaryl）- 1,3-diene and 1-heteroarylbut- 1-en-3-yne derivatives were prepared from 1,4-dichloro-2-butyne and corresponding N-heteroarenes such as imidazole, pyrrole, pyrazole and indole derivatives in the presence of bases in good to high yields.     

η6-苊烯三羰基铬配合物的合成、结构及光谱性质研究

采用苊烯配体与三胺基三羰基铬在四氢呋喃中回流反应,合成了η6-苊烯三羰基铬配合物.通过元素分析、IR、1HNMR、13CNMR、MS和X射线单晶衍射对其结构进行了表征,比较了标题配合物与其自由配体的光物理行为.晶体结构分析表明,标题配合物属单斜晶系,空间群P21/c,Z=4,a=0.8719(7)nm,b=1.2436(10)nm,c=1.1504(9)nm,β=111.835(13)°,Cr(CO)3基团可与苊烯配体中的2个苯环中的任意一个配位,形成2个异构体(R,S),并以1:1的比例在其晶胞单元中反向面对面堆积,这种异构体共存于晶体中归属于Cr(CO)3基团在配体芳环之间的配位移动重排(IRHRs).     

Reaction of halides with tricarbonylcyclohexadienyliron cation: Preparation of tricarbonyl(5exo-Fluorocyclohexa-1,3-diene)iron

Tricarbonyl(5-exo-fluorocyclohexa-1,3-diene)iron has been prepared by reaction of tricarbonyl(cyclohexadienyl)iron cation with KF in the presence of 18-crown-6. Reactions of chloride and bromide salts of potassium also give unstable 5-substituted compounds while the iodo salt reacts to form a mixture of the ring and metal substituted products.     

Reaction of bicyclo[2.2.1]hepta-2,5-diene with the arenesulfenamide—phosphorus(v) oxohalide system: chemo-, regio-, and steroselectivity

The chemo-, regio- and stereoselectivities of electrophilic sulfenylation of bicyclo[2.2.1]hepta-2,5-diene with arenesulfenamides activated by phosphorus(v) oxohalides were studied. The ratio of the products of endo- to exo-attack of the diene by the electrophilic species depends on the solvent nature. The proportions of the products formed upon addition to one double bond and upon homoallylic participation of the second double bond depend on solvent polarity, the nature of the halogen, the substituents in the sulfenamide benzene ring, and on the reaction time. In addition, the formation of mixed adducts was proven for the reaction carried out in acetonitrile and the formation of disulfenylation products was found in the reaction with excess sulfenylating reagent. Isomerization of exo-3-arylthio-endo-2-halobicyclo[2.2.1]hept-5-enes to the products formed with homoallylic participation of the second double bond, exo-5-arylthio-endo-3-halotricyclo[2.2.1.0^2,6]heptanes, was shown to be possible.     

DFT calculation and AIM-analysis of the substituent influence on the structure of (1-azabuta-1,3-diene)tetracarbonyliron(0) complexes

1-Azabuta-1,3-dienes can coordinate to the tetracarbonyliron(0) moiety in four ways, to form (1-azabuta-1,3-diene)tetracarbonyliron(0) complexes with the ligand bonded in an η² fashion through the alkene, η² coordinated through its CN bond, σ-bonded to the lone pair of the nitrogen atom, or η³ coordinated through the CC-C moiety under concomitant coupling of the imine nitrogen with one of the carbonyl ligands to a carbamoyl species. In the experiment, the equilibrium between these species strongly depends on factors such as the nature of the substituents at the ligand, the solvent and the temperature. In this work, DFT calculations (B3LYP/LANL2DZ/6-31G* and 6-311++G**) and an AIM-analysis of the topology of the charge density were used to investigate the influence of the substituents at the 1-azabuta-1,3-diene ligand on the structural, electronic and energetic properties of these constitutional isomers. In most cases, the calculations correctly predict the observed structure, even in situations where the energy differences between related species are rather small. Substituents larger than CH₃ at N and H at C2 disfavour the structures with an η² coordination to the CN bond to such an extent that they cease to exist as minimum energy structures. Also the σ-N forms distort significantly with the introduction of substituents at N or C2 and become energetically less favourable. The geometries of the η²-alkene form do not change much upon substitution, whereas the η³ form tolerates steric strain best and becomes most favourable when the substituent at C2 is large. The activation barrier between the η²-alkene and the η³-allyl form is low (7.5-1.4 kcal/mol) and allows for an equilibration between these species. The conversion of the η²-alkene into the σ-N form requires almost complete dissociation of the ligand from the Fe(CO)₄ moiety. Accordingly, its activation barrier is higher (approx. 14 kcal/mol) and fairly independent of the nature of the substituents at the azabutadiene ligand.     

1,3-Thiazepines. 5. Study of 2-Phenyl(benzyl)iminohexahydro-1,3-thiazepines and Their Derivatives by 13C Spectroscopy

We have studied the ¹³C NMR spectra of 2-phenyl- and 2-benzyliminohexahydro-1,3-thiazepines, and also their alkyl, acyl, carbamoyl, and thiocarbamoyl derivatives. We have shown that introducing substiuents both into the 2 position and into the 3 position of the thiazepine ring mainly affects the chemical shifts for the C(4) of the heterocycle.     

The electronic states of buta-1,3-diene studied by ab initio configuration interaction and DFT methods,and electron energy loss spectroscopy

The electronic vertical excitation energies for singlet and triplet valence, and Rydberg states of trans-buta-1,3-diene have been computed using ab initio multi-reference multi-root CI procedures with a [4s3p3d3f] set of Rydberg functions. Close numerical agreement between theory and experiment was found for a number of low-lying electronic states.     

Acetals and ethers,XVII. One- or two-step syntheses of 2-(2-alkoxyethyl)-1,3-dioxacyclanes

2-(2-Alkoxyethyl)-1,3-dioxanes (1) were prepared by ap-toluenesulfonic acid-catalyzed, one-step reaction of propenal with a mixture of aliphatic alcohol and trimethylene glycol in good yields. The transacetalization reaction of 1,1,3-trialkoxypropanes (3) with ethylene glycol or propylene-(1,2)glycol afforded good yields of pure 2-(2-alkoxyethyl)-1,3-dioxolanes (5 or6), respectively. This reaction proceeds through an intermediate 1,3-dialkoxy-1-(2-hydroxyalkoxy)-propane.

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Ein- oder Zweistufensynthese von 2-(2-Alkoxyethyl)-1,3-dioxacyclanen

Zusammenfassung In der durchp-Toluolsulfonsäure — katalysierten, direkten Reaktion von Propenal mit einem Gemisch von aliphatischem Alkohol und Trimethylenglykol wurden die entsprechenden 2-(2-Alkoxyethyl)-1,3-dioxane (1) in guten Ausbeuten erhalten. Die Umacetalisierung von 1,1,3-Trialkoxypropanen (3) mit Ethylenglykol oder 1,2-Propylenglykol lieferte 2-(2-Alkoxyethyl)-1,3-dioxolane (5 oder6) in guten Ausbeuten. Die Umacetalisierungsreaktion von 1,1,3-Trialkoxypropanen verläuft über 1,3-Dialkoxy-1-(2-hydroxyalkoxy)-propane als Zwischenprodukte.

     

Syntheses,Structures, and Photoluminescent Properties of Two 2D Coordination Polymers Based on 1,3-Di(2,4-dicarboxyphenyl) Benzene and 1,3-Di(4-pyridyl)propane

Two new 2D coordination polymers, [Zn(HL)(Hbpp)]n(1) and [Cd(HL)(Hbpp)(H2O)]n(2)(H4L = 1,3-di(2,4-dicarboxyphenyl) benzene, bpp = 1,3-di(4-pyridyl)propane), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TGA and IR spectroscopy. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 13.1031(6), b = 14.7315(7), c = 15.0041(7) A, β = 91.202(1)°, V = 2895.6(2) A3, Dc = 1.532g/cm3, Mr = 667.97, F(000) = 1376.0, μ = 0.909 mm–1, Z = 4, the final R = 0.0481 and wR = 0.1304 for 7027 observed reflections with I 2σ(I). Complex 2 also belongs to the monoclinic space group P21/n, with a = 13.6326(4), b = 14.6432(4), c = 14.9395(5) A, β = 93.132(1)o, V = 2977.84(16) A3,Dc = 1.613 g/cm3, Mr = 1445.98, F(000) = 733.0, μ = 0.794 mm–1, Z = 2, the final R = 0.0283 and w R = 0.0784 for 7230 observed reflections with I 2σ(I). Both complexes 1 and 2 form 2D net structures, which are further linked to form 3D supramolecular net structures via intermolecular hydrogen bonds and aromatic π-π stacking interactions.     

α-Ureidoalkylation of 1,3-bis(hydroxymethyl)-imidazolidin-2-one

The α-ureidoalkylation of imidazolidine-2,4-dione, urea, carboxylic acid amides, and sulfonamides has been studied using 1,3-bis(hydroxymethyl)-imidazolidin-2-one as ureidoalkylating agent. Methods have been developed for the synthesis of 1,3-bis(2,4-dioxoimidazolidin-1-ylmethyl)-, 1,3-bis(acetylaminomethyl)-, 1,3-bis(benzoylaminomethyl)-, 1,3-bis(phenylsulfonylaminomethyl)-, and 1,3-bis(p-toluenesulfonylaminomethyl)imidazolidin-2-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1655–1659, November, 2007.