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1.
Synthesis and Structure Analysis of (i-Pr)2NB(t-BuP)3 and (i-Pr)2NB(t-BuP)4 The diphosphide K(t-Bu)P-(t-BuP)2-P(t-Bu)K obtained by the cleavage reaction of the 3-membered ring system (i-Pr)2BN(t-BuP)2 with potassium reacts with t-BuPCl2 at ?78°C under ring expansion to form the P3B ring system (i-Pr)2NB(t-BuP)3 – 1,2,3-tri-t-butyl-tri-phospha-4-diisopropyl-aminoboretane ( 1 ). – The 5-membered P4B ring system (i-Pr)2NB(t-BuP)4 – 1,2,3,4-tetra-t-butyl-tetraphospha-5-diisopropylaminoborolidine, ( 2 ) – is formed from K(t-Bu)P? (t-BuP)2? P(t-Bu)K and (i-Pr)2NBCl2 analogous to the above reaction. 1 and 2 could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analysis. 1 shows at 200 K two conformation isomers; for 2 31P-10,11B-isotopic shifts could be identified. 相似文献
2.
JPC – Journal of Planar Chromatography – Modern TLC - Quinolones, because of their hydrophilic (amphiionic) character, are strongly adsorbed by silica even from polar solvents. It has... 相似文献
3.
Synthesis and Characterization of Bis(2‐iminopyrrolyl) Iron(II) Complexes by N–H Bond Activation
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The reactions of 2‐iminopyrroles 1 – 3 with Fe(PMe3)4 afforded the N–H activated bis(2‐iminopyrrolyl) iron(II) complexes 4 – 6 . The structures of compounds 4 – 6 were determined by single‐crystal X‐ray diffraction. The formation mechanism of complexes 4 – 6 was discussed. 相似文献
4.
Paul Margaretha 《Helvetica chimica acta》1979,62(6):1978-1979
The bis(methylthio)benzenes 3a – 3c are oxidized to the methylsulfinyl-methylthiobenzenes 4a – 4c on a Pt-anode in good yields. 相似文献
5.
Beatriz Ballesteros Dr. Gema de la Torre Dr. Axel Shearer Anita Hausmann M. Ángeles Herranz Dr. Dirk M. Guldi Prof. Tomás Torres Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(1):114-125
A novel series of double‐decker lanthanide(III) bis(phthalocyaninato)–C60 dyads [LnIII(Pc)(Pc′)]–C60 (M=Sm, Eu, Lu; Pc=phthalocyanine) ( 1 a – c ) have been synthesized from unsymmetrically functionalized heteroleptic sandwich complexes [LnIII(Pc)(Pc′)] (Ln=Sm, Eu, Lu) 3 a – c and fulleropyrrolidine carboxylic acid 2 . The sandwich complexes 3 a – c were obtained by means of a stepwise procedure from unsymmetrically substituted free‐base phthalocyanine 5 , which was first transformed into the monophthalocyaninato intermediate [LnIII(acac)(Pc)] and further reacted with 1,2‐dicyanobenzene in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU). 1H NMR spectra of the bis(phthalocyaninato) complexes 3 a – c and dyads 1 a – c were obtained by adding hydrazine hydrate to solutions of the complexes in [D7]DMF, a treatment that converts the free radical double‐deckers into the protonated species, that is, [LnIII(Pc)(Pc′)H] and [LnIII(Pc)(Pc′)H]–C60. The electronic absorption spectra of 3 a – c and 1 a – c in THF exhibit typical transitions of free‐radical sandwich complexes. In the case of dyads 1 a – c , the spectra display the absorption bands of both constituents, but no evidence of ground‐state interactions could be appreciated. When the UV/Vis spectra of 3 a – c and 1 a – c were recorded in DMF, typical features of the reduced forms were observed. Cyclic voltammetry studies for 3 a – c and 1 a – c were performed in THF. The electrochemical behavior of dyads 1 a – c is almost the exact sum of the behavior of the components, namely the double‐decker [LnIII(Pc)(Pc′)] and the C60 fullerene, thus confirming the lack of ground‐state interactions between the electroactive units. Photophysical studies on dyads 1 a – c indicate that only after irradiation at 387 nm, which excites both C60 and [LnIII(Pc)(Pc′)] components, a photoinduced electron transfer from the [LnIII(Pc)(Pc′)] to C60 occurs. 相似文献
6.
Xing‐Cai Huang Jia‐Xin Li Yong‐Zhi Chen Wen‐Yan Wang Rui Xu Jin‐Xia Tao Dong Shao Yi‐Quan Zhang 《化学:亚洲杂志》2020,15(9):1469-1477
Tuning the magnetic anisotropy of metal ions remains highly interesting in the design of improved single‐molecule magnets (SMMs). We herein report synthetic, structural, magnetic, and computational studies of four mononuclear CoII complexes, namely [Co(hfac)2(MeCN)2] ( 1 ), [Co(hfac)2(Spy)2] ( 2 ), [Co(hfac)2(MBIm)2] ( 3 ), and [Co(hfac)2(DMF)2] ( 4 ) (MeCN=acetonitrile, hfac=hexafluoroacetylacetone, Spy=4‐styrylpyridine, MbIm=5,6‐dimethylbenzimidazole, DMF=N,N‐dimethylformamide), with distorted octahedral geometry constructed from hexafluoroacetylacetone (hfac) and various axial ligands. By a building block approach, complexes 2 – 4 were synthesized by recrystallization of the starting material of 1 from various ligands containing solution. Magnetic and theoretical studies reveal that 1 – 4 possess large positive D values and relative small E parameters, indicating easy‐plane magnetic anisotropy with significant rhombic anisotropy in 1 – 4 . Dynamic alternative current (ac) magnetic susceptibility measurements indicate that these complexes exhibit slow magnetic relaxation under external fields, suggesting field‐induced single‐ion magnets (SIMs) of 1 – 4 . These results provide a promising platform to achieve fine tuning of magnetic anisotropy through varying the axial ligands based on Co(II) bis(hexafluoroacetylacetonate) complexes. 相似文献
7.
JPC – Journal of Planar Chromatography – Modern TLC - Adsorption of Zn(II) and Cd(II) ions on soil TLC plates was studied using aqueous solutions of surfactants as mobile phases. The... 相似文献
8.
W.-D. Hergeth I. Alig J. Lange J. R. Lochmann T. Scherzer S. Wartewig 《Macromolecular Symposia》1991,52(1):289-296
The physical aspects of the clouding phenomenon in the aqueous solution of a poly(oxyethylene)(POE) – poly(oxypropylene)(POP) – poly(oxyethylene)(POE) triblock copolymer were investigated by applying various experimental methods: viscometry, ultrasonic technique, light scattering, infrared and Raman spectroscopy. The ultrasonic absorption studies hint at a critical behaviour. In order to understand the spectroscopic findings, conformational energies of model POE molecules as well as interaction energies between oxyethylene (OE) units and water molecules were calculated by the use of the quantum chemical PCILO method. It is suggested that the clouding is connected with conformational changes of POE segments. 相似文献
9.
Dr. Nithin Suryadevara Dr. Asato Mizuno Lea Spieker Dr. Soma Salamon Stephan Sleziona André Maas Dr. Erik Pollmann Dr. Benoît Heinrich Prof. Dr. Marika Schleberger Prof. Dr. Heiko Wende Dr. Senthil Kumar Kuppusamy Prof. Dr. Mario Ruben 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(6):e202103853
Bistable spin-crossover (SCO) complexes that undergo abrupt and hysteretic (ΔT1/2) spin-state switching are desirable for molecule-based switching and memory applications. In this study, we report on structural facets governing hysteretic SCO in a set of iron(II)-2,6-bis(1H-pyrazol-1-yl)pyridine) (bpp) complexes – [Fe(bpp−COOEt)2](X)2 ⋅ CH3NO2 (X=ClO4, 1 ; X=BF4, 2 ). Stable spin-state switching – T1/2=288 K; ΔT1/2=62 K – is observed for 1 , whereas 2 undergoes above-room-temperature lattice-solvent content-dependent SCO – T1/2=331 K; ΔT1/2=43 K. Variable-temperature single-crystal X-ray diffraction studies of the complexes revealed pronounced molecular reorganizations – from the Jahn-Teller-distorted HS state to the less distorted LS state – and conformation switching of the ethyl group of the COOEt substituent upon SCO. Consequently, we propose that the large structural reorganizations rendered SCO hysteretic in 1 and 2 . Such insights shedding light on the molecular origin of thermal hysteresis might enable the design of technologically relevant molecule-based switching and memory elements. 相似文献
10.
JPC – Journal of Planar Chromatography – Modern TLC - Enantioseparation of (RS)-etodolac was achieved by an indirect approach. Extraction of the drug (RS)-etodolac (Etd) was done from... 相似文献
11.
Gimranov Dmitriy R. Abdullina Aisylu F. Sevast’yanova Ekaterina V. Petrova Yuliya Yu. 《平面色谱法杂志一现代薄层色谱法》2015,28(5):343-351
JPC – Journal of Planar Chromatography – Modern TLC - The thin-layer chromatography (TLC) procedures of metal cations, modified with amines and cationic surfactant micelles, followed by... 相似文献
12.
Holger Lang Margarete Gottlieb Michael Schwarz Silke Farkas BerndS. Schulz Frank Himmelsbach Ramamurthy Charubala Wolfgang Pfleiderer 《Helvetica chimica acta》1999,82(12):2172-2185
A series of new base-protected and 5′-O-(4-monomethoxytrityl)- or 5′-O-(4,4′-dimethoxytrityl)-substituted 3′-(2-cyanoethyl diisopropylphosphoramidites) and 3′-[2-(4-nitrophenyl)ethyl diisopropylphosphoramidites] 52 – 66 and 67 – 82 , respectively, are prepared as potential building blocks for oligonucleotide synthesis (see Scheme). Thus, 3′,5′-di-O-acyl- and N 2,3′-O,5′-O-triacyl-2′-deoxyguanosines can easily be converted into the corresponding O6-alkyl derivatives 6 , 8 , 10 , 12 , 14 , and 16 by a Mitsunobu reaction using the appropriate alcohol. Mild hydrolysis removes the acyl groups from the sugar moiety (→ 9 , 11 , 13 , 15 , and 19 (via 18 ), resp.) which can then be tritylated (→ 38 – 42 ) and phosphitylated (→ 57 – 61 ) in the usual manner. N 2-[2-(4-nitrophenyl)ethoxycarbonyl]-substituted and N 2-[2-(4-nitrophenyl)ethoxycarbonyl]-O6-[2-(4-nitrophenyl)ethyl]-substituted 2′-deoxyguanosines 5 and 7 , respectively, are synthesized as new starting materials for tritylation (→ 28 , 35 , and 37 ) and phosphitylation (→ 54 , 56 , 70 , and 78 ). Various O4-alkylthymidines (see 20 – 24 ) are also converted to their 5′-O-dimethoxytrityl derivatives (see 43 – 47) and the corresponding phosphoramidites (see 62 – 66 and 79 – 82 ). 相似文献
13.
Charge decay properties at 90°C have been studied for four poly(propylene) (PP) samples of different content of isotactic (mm), syndiotactic (rr) and heterotactic (mr, rm) triads. Comparing the charge decay properties with the previously measured space charge distribution and taking into account the specific stereochemical sequences which characterize each of the samples, it is apparent that mmrm and rrrm sequences furnish better storage properties. In contrast, mmrr and short heterotactic sequences would both exhibit worse retention power of negative and positive charge. Correlations – although still tentative – justify those specific stereochemical sequences as being well defined factors for determining the electrical properties of PP. 相似文献
14.
Novel Transition‐Metal (M=Cr,Mo, W,Fe) Carbonyl Complexes with Bis(guanidinato)silicon(II) Ligands
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Felix M. Mück Dorit Kloß Johannes A. Baus Dr. Christian Burschka Prof. Dr. Reinhold Tacke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(31):9620-9626
The donor‐stabilized silylene 2 (the first bis(guanidinato)silicon(II ) complex) reacts with the transition‐metal carbonyl complexes [M(CO)6] (M=Cr, Mo, W) to form the respective silylene complexes 7 – 10 . In the reactions with [M(CO)6] (M=Cr, Mo, W), the bis(guanidinato)silicon(II ) complex 2 behaves totally different compared with the analogous bis(amidinato)silicon(II ) complex 1 , which reacts with [M(CO)6] as a nucleophile to replace only one of the six carbonyl groups. In contrast, the reaction of 2 leads to the novel spirocyclic compounds 7 – 9 that contain a four‐membered SiN2C ring and a five‐membered MSiN2C ring with a M?Si and M?N bond (nucleophilic substitution of two carbonyl groups). Compounds 7 – 10 were characterized by elemental analyses (C, H, N), crystal structure analyses, and NMR spectroscopic studies in the solid state and in solution. 相似文献
15.
Bastian Theis Dipl.‐Chem. Stefan Metz Dr. Christian Burschka Dr. Rüdiger Bertermann Dr. Stefan Maisch Reinhold Tacke Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(30):7329-7338
The neutral pentacoordinate silicon(IV) complexes 1 (SiS2ONC skeleton), 2 (SiSeSONC), 3 (SiTeSONC), 6 / 9 (SiSe2O2C), 7 (SiSe2S2C), and 8 / 10 (SiSe4C) were synthesized and structurally characterized by using single‐crystal X‐ray diffraction and multinuclear solid‐state and solution‐state (except for 6 – 9 ) NMR spectroscopy. With the synthesis of compounds 1 – 3 and 6 – 10 , it has been demonstrated that pentacoordinate silicon compounds with soft chalcogen ligand atoms (S, Se, Te) can be stable in the solid state and in solution. 相似文献
16.
Baošić Rada M. Milojković-Opsenica Dušanka M. Tešić Živoslav Lj. 《平面色谱法杂志一现代薄层色谱法》2003,16(6):412-416
JPC – Journal of Planar Chromatography – Modern TLC - The effect of substituents of the β-ketoiminato ligand of 24 cop-per(H) and nickel(H) complexes on hRF values obtained by TLC... 相似文献
17.
《Analytical letters》2012,45(10):1557-1565
Abstract A spectrometric study of the reaction between Pd(II), Fe(III) and Pt(IV) ions, and Mandelazo I was carried out. The optimum conditions favouring the formation of the complexes are extensively investigated. The stoichiometry of the complexes formed in solution (1:2, 1:1, 1:1), their apparent stability constants (5.45 × 109, 2.39 × 106, 4.12 × 105) and the ranges for obedience to beer's law (0.2 – 6.4, 0.25 – 7.0, 1.5 – 42.0 μg/mL) are reported for Pd(II), Fe(III) and Pt(IV), respectively. The effect of some metal ions including Cu(II), Zn(II), Mn(II), Cd(II), Hg(II), Co(II), Ni(II), Be(II), Al(III), Th(IV) and U(VI), on the maximum absorbance of the formed complexes was also investigated. 相似文献
18.
Vibrational Spectra and Force Constants of the Series OP(N(CH3)2)3 – OP(CH3)3 and SP(N(CH3)2)3 – SP(CH3)3 The vibrational spectra (IR and Raman) of the compounds of the title series are recorded and assigned to the normal vibrations. By a simplified force field the valence force constants are calculated and discussed. The results are compared with those of the NMR spectroscopy. 相似文献
19.
The starting substrate 3‐(3‐(1‐naphthyl)acryloyl)tropolone ( 3 ) was achieved by the aldol condensation reaction of 3‐acetyltropolone with 1‐naphthaldehyde. Compound 3 reacted with bromine to afford 7‐bromo‐3‐ (3‐(1‐naphthyl)acryloyl)tropolone ( 4 ), 5,7‐dibromo‐3‐(3‐(1‐naphthyl)acryloyl)tropolone (5) according to the molar ratio of the reactants. Iodination of 3 gave 7‐iodo‐3‐(3‐(1‐naphthyl)acryloyl)tropolone ( 6 ). Azo‐coupling reactions of 3 gave the 5‐arylazo‐3‐(3‐(1‐naphthyl)acryloyl)tropolones ( 7 – 8 ). Compounds 3 , 4 , 6 reacted respectively with hydroxyamine to give the corresponding 3‐[2‐(1‐naphthyl)vinyl]‐8H‐cyclohepta[d]isoxazol‐8‐ones ( 9 – 11 ). The reactions of 3 , 5 with phenylhydrazine and substituted phenylhydrazines gave 3‐[2‐(1‐naphthyl)vinyl]‐1‐phenylcyclohepta[c]pyrazol‐8(1H)‐ones ( 12 – 18 ). 相似文献
20.
Fernanda M. de Oliveira Affonso C. Gonçalves Jr Douglas C. Dragunski Mariana G. Segatelli 《International journal of environmental analytical chemistry》2013,93(10):1061-1071
The present paper describes the feasibility of on-line preconcentration of nickel ions from aqueous medium on Ni(II)-imprinted cross-linked poly(methacrylic acid) (IIP) synthesised through a double-imprinting method and their subsequent determination by FAAS. The proposed method consisted in loading the sample (20.0 mL, pH 7.25) through a mini-column packed with 50 mg of the IIP for 2 min. The elution step was performed with 1.0 mol L?1 HNO3 at a flow rate of 7.0 mL min?1. The following parameters were obtained: quantification limit (QL) – 3.74 µg L?1, preconcentration factor (PF) – 36, consumption index (CI) – 0.55 mL, concentration efficiency (CE) – 18 min?1, and sample throughput – 25 h?1. The precision of the procedure assessed in terms of repeatability for ten determinations was 5.6% and 2.5% for respective concentrations of 5.0 and 110.0 µg L?1. Moreover, the analytical curve was obtained in the range of 5.0–180.0 µg L?1 (r = 0.9973), and a 1.64-fold increase in the method sensitivity was observed when compared with the analytical curve constructed for the NIP (non-imprinted polymer), thus suggesting a synergistic effect of the Ni(II) ions and CTAB on the adsorption properties of the IIP. The practical application of the adsorbent was evaluated from an analysis of tap, mineral, lake and river water. Considering the results of addition and recovery experiments (90.2–100 %), the efficiency of this adsorbent can be ensured for the interference-free preconcentration of the Ni(II) ions. 相似文献