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1.
A new chromone-substituted dihydrotriflavonol, (2S,3S)[6-{(3S) 3″,5″-dihydroxy-6″-methoxydihydrochromone}5,3′,4′,5′-tetrahydroxy-7-methoxy-3-O-8-dihydroflavone]2 3-O-8[6-{(3S) 3″,5″-dihydroxy-6″methoxydihydrochromone}3,5,3′,4′,5′-pentahydroxy-7-methoxydihydroflavonol] was isolated from the leaves
of Anogeissus pendula. The structure was determined by UV, 1H NMR, 13C NMR, HMBC, and CD data. 相似文献
2.
Gordana P. Radi? Verica V. Glo?ovi? Goran N. Kalu?erovi? Frank W. Heinemann Sre?ko R. Trifunovi? 《Transition Metal Chemistry》2011,36(4):331-336
The reaction of K2[PdCl4] with [(S,S)-H2(Et)2eddv]Cl2 diester (O,O′-diethyl-(S,S)-ethylenediamine-N,N′-di-2-(3-methyl)butanoate) (1) resulted in [PdCl2{(S,S)-(Et)eddv-κ2
N,N′,κO}] (2) complex with one hydrolyzed ester group. The compound was characterized by spectroscopic methods and it was found that the
reaction is diastereoselective (1H and 13C NMR; one diastereoisomer of four possible). In addition, the structure of 2 was confirmed by X-ray diffraction analysis, indicating that the product is the (R,R)–N,N′-configured isomer. DFT calculations support the formation of one diastereoisomer of 2. 相似文献
3.
Serafino Gladiali Serenella Medici Tamàs Kégl Làszlò Kollàr 《Monatshefte für Chemie / Chemical Monthly》2000,131(12):1351-1361
Summary. The reaction of dinuclear rhodium(I) derivatives of the formula [Rh(DIOL)X]2 with the axially chiral phosphinyl phosphane 2-(diphenylphosphinyl)-2′-(diphenylphosphanyl)-1,1′-binaphthalene ((S)-BINAPO, 1) leads to the formation of cationic complexes [(BINAPO)Rh(DIOL)]+ where the ligand (S)-BINAPO consistently displays a P,O-chelate coordination which is mantained even in solvents of fair polarity. The mononuclear rhodium(I)
complexes (S)-2-diphenylphosphanyl-2′-diphenylphosphinyl-1,1′-binaphthalene-(1,5-cyclooctadiene) rhodium tetrafluoroborate (3b) and (S)-2-diphenylphosphanyl-2′-diphenylphosphinyl-1,1′-binaphthalene-(1,4-norbornadiene) rhodium tetrafluoroborate (3c) with 1,5-cyclooctadiene (COD) and 2,5-norbornadiene (NBD) as the diolefin were isolated and characterized. Both show a fluxional behaviour in solution which is due to the mobility
of the diolefin rather than to a displacement-recombination of the oxygenated arm of the ligand. The mobility of the 1,4-norbornadiene
ligand in 3c is extremely pronounced and the coordinated diolefin flexibility could be frozen only at about 200 K. These complexes are
active but poorly stereoselective catalysts for the hydrogenation, hydroboration, and hydroformylation of alkenes.
Received June 16, 2000. Accepted (revised) July 24, 2000 相似文献
4.
Lutz Preu Wolfgang Kliegel Steven J. Rettig James Trotter 《Monatshefte für Chemie / Chemical Monthly》2001,132(10):1213-1224
Summary. The structure of the dehydrogenation product 1′,3a′-dihydro-3′-((1,3-dioxoindan-2-ylidene)-phenyl-methyl)-5′-phenyl-spiro-(indan-2,1′-pyrrolo[3,4-c]pyrrole)-1,3,4′,6′-(5′H, 6a′H)-tetrone derived from the cycloadducts (±)-(3a′S,6a′R)-1′,3a′-dihydro-3′-((R)-α-(1,3-dioxoindanyl)-benzyl)-5′-phenyl-spiro-(indan-2,1′-pyrrolo[3,4-c]pyrrole)-1,3,4′,6′(5H,6a′H)-tetrone and/or (±)-(3a′S,6a′R)-1′,3a′-dihydro-3′-((S)-α-(1,3-dioxoindanyl)-benzyl)-5′-phenyl-spiro-(indan-2,1′-pyrrolo[3,4-c]pyrrole)-1,3,4′,6′(5H,6a′H)-tetrone, which were synthesized by 1,3-dipolar cycloaddition of N-phenylmaleimide to 2-((2-(1,3-dioxoindan-2-yl)-2-phenyl-ethenyl)-imino)-indan-1,3-dione,
was determined by X-ray analysis. Crystal data (CCD, 180 K): rhombohedral, R&3macr;;, a = 34.0871(7), c = 13.9358(5) ?, Z = 18; the structure was solved by direct methods and refined by full-matrix least-squares procedures to R(F, I ≥ 3σ(I)) = 0.053. The molecule contains a central folded ring system of two cis-fused 5-membered heterocyclic rings; each ring is nearly planar, and the angle between the rings amounts to 59.0°. Dynamic
1H NMR spectroscopy of the product revealed an exchange process caused by restricted rotation of the double bonded 1,3-indandione
moiety and the phenyl group about the Csp2-Csp2 single-bonds. Molecular modeling and complete lineshape analysis indicated a four site exchange process for which free energies
of activation and free energies could be established. ΔG
‡ values for the barriers of rotation are in the range of 57–59 kJ · mol − 1 at 273 K, which is unusually high for an unsubstituted phenyl group.
Received May 3, 2001. Accepted (revised) June 8, 2001 相似文献
5.
Sushanta Saha Prodyut Kumar Sarkar Ambikesh Mahapatra 《Transition Metal Chemistry》2006,31(3):389-395
The reaction between Pd(N,N′)Cl2 [N,N′ ≡ 1-alkyl-2-(arylazo)imidazole (N,N′) and picolinic acid (picH) have been studied spectrophotometrically at λ = 463 nm in MeCN at 298 K. The product is [Pd(pic)2] which has been verified by the synthesis of the pure compound from Na2[PdCl4] and picH. The kinetics of the nucleophilic substitution reaction have been studied under pseudo-first-order conditions.
The reaction proceeds in a two-step-consecutive manner (A → B → C); each step follows first order kinetics with respect to
each complex and picH where the rate equations are: Rate 1 = {k′0 + k′2[picH]0} × [Pd(N,N′)Cl2] and Rate 2 = {k′′0 + k′′2[picH]0}[Pd(N,O)(monodentate N,N′)Cl2] such that the first step second order rate constant (k′2) is greater than the second step second order rate constant (k′′2). External addition of Cl− (as LiCl) suppresses the rate. Increase in π-acidity of the N,N′ ligand, increases the rate. The reaction has been studied
at different temperatures and the activation parameters (Δ‡H° and Δ‡S°) were calculated from the Eyring plot. 相似文献
6.
The reaction of [PtMe3(bpy)(Me2CO)](BF4) (2) (prepared from [PtMe3I(bpy)] (1) plus Ag(BF4)) with MeSSMe resulted in the formation of [PtMe3(bpy)(MeSSMe-κS)](BF4) (3). A single-crystal X-ray diffraction analysis revealed in the octahedral Pt(IV) complex (configuration index: OC-6-33), a conformation of the monodentately κS bound MeSSMe ligand (C–S–S–C 92.7(4)°) being very close to that in non-coordinated MeSSMe, thus allowing some hyperconjugative
interaction stabilizing the S–S bond. The reaction of [K(18C6)][(PtMe3)2(μ-I)(μ-pz)2] (4; 18C6 = 18-crown-6, Hpz = pyrazole) with Ag(BF4) and MeSSMe resulted in the formation of dinuclear complexes [(PtMe3)2(μ-pz)2(μ-MeSSMe)] existing at room temperature in acetone solution as different fast interconverting isomers. At –40 °C, two isomers
with a μ-1κS:2κS (5a) and a μ-1κS:2κS′ (5b) coordinated MeSSMe ligand in the ratio 2:1 could be identified 1H NMR spectroscopically. DFT calculations of type 5 complexes revealed the existence of two conformers with a μ-MeSSMe-1κS:2κS ligand, which differ mainly in the C–S–S–C dihedral angle (66.4 vs. 180.0° 6a/6a′). They have essentially the same energy and a very low activation barrier in acetone as solvent (1.3 kcal/mol) for their
mutual interconversion. A further equilibrium structure was identified to be an isomer having a μ-MeSSMe-1κS:2κS′ ligand (6b) that proved to be only 1.9 kcal/mol higher in energy than 6a/6a′. 相似文献
7.
Zhiping Wu Yu Chen Xu Feng Bing Xia Ming Wang Yunfa Dong 《Chemistry of Natural Compounds》2010,46(2):187-191
From the the bulbs of Zephyranthes candida (Amaryllidaceae), another two novel ceramides have been isolated and identified. The structures of the two novel compounds
were established as (2S,3S,4R,21E,2′R)2-[N-(2′-hydroxynonadecanoyl)-N-(1′′,2′′-dihydroxyethyl)amino]-21-hexacosene-1,3,4-triol, named zephyranamide C (1), and 1,3,4,5,6-pentahydroxy-2-(2′-hydroxyhexacosanoyl-amino)-18-(E)-tetracosene, named zephyranamide D (2). Their structures and stereochemistries were elucidated by spectral techniques including 1H NMR, 13C NMR, as well as HSQC, HMBC, DEPT, and COSY. 相似文献
8.
Yakup Baran Ismet Kaya Murat Turkyılmaz 《Journal of Thermal Analysis and Calorimetry》2012,107(3):869-875
The new tetradentate symmetrical (2R,2′S)-1,1′-piperazine-1,4-diyldipropane-2-thiol) (L1), (2S)-1-[bis(2-aminoethyl)amino]propan-2-ol) (L2), and 2-{(E)-[((1R,2S)-2-{[(1Z)-(2-hydroxy phenyl)methylene]amino}cyclohexyl)imino]methyl}phenol (L3) ligands were synthesized and characterized on the basis of FT-IR, 1H, 13C NMR, EI mass, and elemental analysis. Three commercially available ligands, (2,2′-[ethane-1,2-diylbis(thio)]diethanol (L4), 2,2′-dithiodiethanenamine (L5), and (2,2′-[ethane-1,2-diyldi(imino)] diethanol (L6), were also studied. Pt(II) complexes were characterized by FTIR, elemental analysis and thermal methods. Thermal behaviors
of these complexes were investigated in the range 10–1000 °C. Magnetic properties were also studied, and the all complexes
were found to be diamagnetic. The structures consist of the monomeric units in which the Pt(II) atoms exhibit square planar
geometry. N,N′-bis(salicylidene)-1,2-cyclohexane has been synthesized and characterized by X-ray single crystal diffraction measurement.
The ligand crystallizes in monoclinic crystal system and space group, Cc. 相似文献
9.
Rakesh K. Rath G. A. Nagana Gowda Akhil R. Chakravarty 《Journal of Chemical Sciences》2002,114(5):461-472
2D NMR spectroscopy has been used to determine the metal configuration in solution of three complexes, viz. [(η6-p-cymene)Ru(L*)Cl] (1) and [(η6-p-cymene)Ru(L*)(L′)] (C1O4) (L′ = H2O,2; PPh3,3), where L* is the anion of (S)-(l-phenylethyl)salicylaldimine. The complexes exist in two diastereomeric forms in solution. Both the (RRu,Sc)- and (SRu,Sc)-diastereomers display the presence of attractive CH/π interaction involving the phenyl group attached to the chiral carbon
and the cymene ring hydrogens. This interaction restricts the rotation of the C*-N single bond and, as a result, two structural
types with either the hydrogen atom attached to the chiral carbon (C*) or the methyl group attached to C* in close proximity
of the cymene ring protons get stabilized. Using 2D NMR spectroscopy as a tool, the spatial interaction involving these protons
are studied in order to obtain the metal configuration(s) of the diastereomeric complexes in solution. This technique has
enabled us to determine the metal configuration as (R
Ru,S
c) for the major isomers of 1–3 in solution. 相似文献
10.
[PdCl(terpy)]Clċ3H2O has been synthesized both by interaction of [PdCl4]2− and cis-[Pd(DMSO)2Cl2] with terpy (2,2′:6′,2′′-terpyridine). Complex formation of [PdCl(terpy)]+ with L-cysteine, S-methyl-L-cysteine, and L-methionine was studied as a function of temperature (298–308 K) using of stopped-flow spectrophotometry in methanol-water
(95:5 (v/v)). The ionic strength and acidity of the solutions were adjusted to 0.10 molċdm−3 with CH3SO3H. The second-order rate constant for the reaction of [PdCl (terpy)]+ with L-cysteine amounts to 9.60±0.5 M
−1s−1. L-Methionine and S-methyl-L-cysteine are unreactive under the same experimental conditions. The entropy of activation is strongly negative, which is
compatible with an associative mechanism. 相似文献
11.
Adrian B. Chaplin Zoltán Béni Christian G. Hartinger Hisham Ben Hamidane Andrew D. Phillips Rosario Scopelliti Paul J. Dyson 《Journal of Cluster Science》2008,19(1):295-309
The new mixed-metal complex {anti-[(p-cymene)RuCl]-μ-[κ
2-P,P′;κ
1-P′′-(PPh2CH2)3CMe]-[AuCl]}PF6 and its cluster derivative {anti-[(p-cymene)RuCl]-μ-[κ
2-P,P′;κ
1-P′′-(PPh2CH2)3CMe]-[AuPt3(CO)3(PCy3)3]}(PF6)2 have been prepared and characterized. Notably, NMR spectroscopy and high resolution FT-ICR mass spectrometry, including a
tandem mass spectrometric analysis, demonstrated the formation of these compounds that was also confirmed by single crystal
X-ray diffraction analysis. 相似文献
12.
I. P. Romanova S. G. Fattakhov A. A. Nafikova I. I. Vandyukova R. R. Shagidullin N. M. Azancheev V. S. Reznik O. G. Sinyáshin 《Russian Chemical Bulletin》1998,47(9):1812-1819
The reactions of phosphine derivatives of diallyl isocyanurates with palladium(ii) dichloride lead to the formation of complexes, whose structure, composition, and stability depend on the length of the methylene
chain between the isocyanurate and diphenylphosphine fragments in the ligand. 1,3-Diallyl-5-[5′-(diphenylphosphino)pentyl
and 10′-(diphenyl-phosphino)decyl] isocyanurates with PdCl2 form monomeric L2PdCl2
trans-complexes in which P atoms of the ligands participate in coordination with the metal. 1,3-Diallyl-5-[2′-(diphenylphosphino)ethyl]
isocyanurate with PdCl2 forms a dimeric (LPdCl2)2 complex, which decomposes in a solution to the monomer including solvent molecule into the coordination sphere of the metal.
The reactions of 1,3-diallyl-5-[4′-(diphenylphosphino)butyl] isocyanurate and 1,3-diallyl-5-[6′-(diphenylphosphino)hexyl]
isocyanurate with PdCl2 give monomeric chelate LPdCl2 complexes in which one of the allyl groups of the isocyanurate cycle participates in coordination with the central ion along
with the phosphorus atom.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1859–1865, September, 1998. 相似文献
13.
M. O. Talismanova A. A. Sidorov G. G. Aleksandrov V. N. Charushin S. K. Kotovskaya V. P. Ananikov I. L. Eremenko I. I. Moiseeva 《Russian Chemical Bulletin》2008,57(1):47-55
The reactions of palladium(II) salts with 2-mercaptobenzimidazole (HL) and its 5,6-difluorinated derivative (HLF) were investigated. In the presence of hydrochloric acid, PdCl2 and K2PdCl4 react with HL and HLF in the ethanol—water and acetonitrile—water systems to form the mono-nuclear dicationic complexes [Pd(HL)4]Cl2 (1) and [Pd(LF)4]Cl2 (2). In the absence of HCl, the reactions afford the tetranuclear complex Pd4[(L)2(μ3-S,N-(L))2(μS,N-(L))4] (3). The reaction of triethylamine with an ethanolic solution of 3 leads to degradation of 3 and the formation of the lantern-type dinuclear complex Pd2[(μ2-(L)4] (4), in which the palladium atoms are in the nonequivalent coordination environment, PdN4 and PdS4. The reaction of K2PdCl4 with HL or HLF in the THF—water or acetonitrile—water systems (for the reaction with HLF) in the presence of Et3N produces the lantern-type dinuclear complexes Pd2[(μS,N′-(L3))4] and Pd2[(μ-S,N′-(LF))4] (5), in which the metal atoms are in the equivalent coordination environment (cis-PdN2S2).
Dedicated to Academician G. A. Tolstikov on the occasion of his 75th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 45–52, January, 2008. 相似文献
14.
D. A. Safin M. Bolte M. G. Babashkina A. Klein 《Russian Journal of General Chemistry》2010,80(7):1263-1266
The reaction of N-(diisopropoxyphosphorothioyl)-N′,N′-dimethylthiourea [Me2NC(S)NHP(S)(OPr-i)2, HL) potassium salt with Co(II) cation in aqueous ethanol gave the chelate complex Co(L-S,S′)2(CoL2). The structure of the resulting compound was studied by means of IR spectroscopy, microanalysis, and X-ray analysis. The
metal center was found to occur in a tetrahedral S4 environment formed by the C=S and P=S sulfur atoms of two deprotonated ligands L. Magnetic properties of the complex CoL2 were also studied. 相似文献
15.
A novel one-dimensional dicyanamide bridged lead(II) complex containing nitronyl nitroxide radicals, [Pb(NIT-1′-MeBzIm)(Dca)2]
n
(Dca = dicyanamide anion, NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide),
has been prepared and characterized by magnetic and single-crystal X-ray diffraction studies. In the complex, Pb2+ ion shows seven-coordinate geometry. A chain structure with single, symmetrical, end-to-end Dca bridges is found in the compound.
These units develop as 1D species, where dicyanamide ligands bridge Pb2+ ions. Otherwise, molecules are linked by π-π-piling interactions to form 2D network structure. Magnetic investigation indicates
the existence of intramolecular interactions, wich are ferromagnetic with J = 23.6 cm−1, where the spin Hamitonian is defined as H = −2Σ
i,j
J
i,j
S
i
S within the complex. 相似文献
16.
Giuseppe Tresoldi Santo Di Pietro Dario Drommi Santo Lanza 《Transition Metal Chemistry》2010,35(2):151-158
The solvento species obtained by the treatment of cis-RuCl2(N,N-L)2 [L = di-2-pyridyl sulfide (dps), di-2-pyrimidyl sulfide (dprs)] with AgPF6, reacted with dithioethers L′ [L′ = 2,6-bis(2-pyridylthiomethyl)pyridine (pytmp), 2,6-bis(2-pyrimidylthiomethyl)pyridine (prtmp) and 2,6-bis{2-(4-methyl)pyrimidylthiomethyl}
pyridine (mprtmp)] to afford the compounds [Ru(N,N-L)2(N,S-L′)][PF6]2. The 1H NMR spectra indicate that L′ is chelated through S and N atoms with the formation of a four-membered ring. As a consequence, the ruthenium and sulfur
atoms are stereogenic centers with ∆ and Λ and (R) and (S) configurations, respectively. NMR spectra, at low temperatures, show that two invertomers, of similar abundance, as enantiomeric
couples ∆S, ΛR and ∆R, ΛS are present. In the methylene region, four AB systems are observed that in both the species contain
two non-equivalent methylene groups. Variable-temperature NMR spectra and EXSY experiments show that the sulfur inversion
produces an exchange between the invertomers. The one-dimensional band-shape analysis of the exchanging methylene signals
showed that the energy barriers for the process are in the 43–52 kJ mol−1 range. The possible mechanisms of the sulfur inversion are discussed. 相似文献
17.
Rhony Aufdenblatten Simon Diezi Antonio Togni 《Monatshefte für Chemie / Chemical Monthly》2000,37(5):1345-1350
Starting from the dinuclear chloro-bridged Ir(I) complexes [IrCl(PP)]2 (PP = (R)-(6,6′-dimethylbiphenyl-2,2′-diyl)-1,1′-bis-(diphenylphosphine), (R)-(6,6′-dimethoxy-biphenyl-2,2′-diyl)-1,1′-bis-(diphenylphosphine), and (R)-1-((S)-2-(diphenylphosphino-ferrocenyl))-ethyldicyclohexylphosphine), a new class of cyclopentadienyl Ir(I) complexes containing
a chiral bisphosphine ([IrCp(PP)]) was prepared and characterized. These new complexes are suited precatalysts for the direct hydroarylation of norbornene
with benzamide. 2-(exo-Norbornyl)-benzamide is formed with an enantiomeric excess of up to 94% by the use of 1 mol% iridium, albeit in low yield. 相似文献
18.
Zhiping Wu Yu Chen Xu Feng Bing Xia Ming Wang Yunfa Dong 《Chemistry of Natural Compounds》2009,45(6):829-833
Two new ceramides were isolated from the bulbs of Zephyranthes candida. Their structures were established as (2S,3S,4R,13E)-1,3,4-trihydroxy-2-[(2′R)-2′-hydroxytetracosanoylamino]-13-octadecene, named zephyranamide A (1) and (2S,3S,4R)-1,3,4-trihydroxy-2-octacosanoylaminohexadecene, named zephyranamide B (2). The structures of the new compounds were elucidated by spectral techniques including 1H NMR, 13C NMR, as well as HSQC, HMBC, DEPT, and COSY. 相似文献
19.
The cyclopropylcarbinyl rearrangement of (1R,1′ S,2S)-1-(3-diisopropylamino-3-oxo-propyl)-2-(1-hydroxyethyl)cyclopropane and the participation of the amide moiety in the intramolecular
process smoothly affords the (2′ E,5S)- N,N-diisopropyl-N-[5-(but-2′-enyl)tetra-hydrofuran-2-yridene ] ammonium salt. 相似文献
20.
Rhony Aufdenblatten Simon Diezi Antonio Togni 《Monatshefte für Chemie / Chemical Monthly》2000,131(12):1345-1350
Summary. Starting from the dinuclear chloro-bridged Ir(I) complexes [IrCl(PP)]2 (PP = (R)-(6,6′-dimethylbiphenyl-2,2′-diyl)-1,1′-bis-(diphenylphosphine), (R)-(6,6′-dimethoxy-biphenyl-2,2′-diyl)-1,1′-bis-(diphenylphosphine), and (R)-1-((S)-2-(diphenylphosphino-ferrocenyl))-ethyldicyclohexylphosphine), a new class of cyclopentadienyl Ir(I) complexes containing
a chiral bisphosphine ([IrCp(PP)]) was prepared and characterized. These new complexes are suited precatalysts for the direct hydroarylation of norbornene
with benzamide. 2-(exo-Norbornyl)-benzamide is formed with an enantiomeric excess of up to 94% by the use of 1 mol% iridium, albeit in low yield.
Received July 10, 2000. Accepted August 27, 2000 相似文献