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1.
Prof. Dr. Francesc Teixidor Prof. Dr. Reijo Sillanpää Dr. Ariadna Pepiol Marius Lupu Prof. Dr. Clara Viñas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(36):12778-12786
o‐Carborane (C2B10H12) was adapted to perform as the core of globular macromolecules, dendrons or dendrimers. To meet this objective, precisely defined substitution patterns of terminal olefin groups on the carborane framework were subjected to Heck cross‐coupling reactions or hydroboration leading to hydroxyl terminated arms. These led to new terminal groups (chloro, bromo, and tosyl leaving groups, organic acid, and azide) that permitted ester production, click chemistry, and oxonium ring opening to be performed as examples of reactions that demonstrate the wide possibilities of the globular icosahedral carboranes to produce new dendritic or dendrimer‐like structures. Polyanionic species were obtained in high yield through the ring‐opening reaction of cyclic oxonium compound [3,3′‐Co(8‐C4H8O2‐1,2‐C2B9H10)(1′,2′‐C2B9H11)] by using terminal hydroxyl groups as nucleophiles. These new polyanionic compounds that contain multiple metallacarborane clusters at their periphery may prove useful as new classes of compounds for boron neutron capture therapy with enhanced water solubility and as cores to make a new class of high‐boron globular macromolecules. 相似文献
2.
Á. Gyömöre 《Journal of organometallic chemistry》2011,696(8):1626-1631
A series of planar chiral ferroceno[d]pyridazinones was prepared by hydrazine-mediated cyclisations of (Sp)-2-formylferrocenoyl fluoride obtained in two steps from (2S,4S)-4-(methoxymethyl)-2-ferrocenyl-1,3-dioxane. Further derivatives based on the novel heterocyclic scaffold were resulted by means of the facile N-alkylation reactions carried out on the easily accessible fused product derived from the hydrazine-mediated cyclisation. Upon treatment with hydrazine (Sp)-2-formylferroce carboxylic acid, the precursor of the acid fluoride with enhanced reactivity, afforded a dimeric azine avoiding cyclisation. The spectacular difference between the experimentally observed reactivity of the bifunctional formylferrocenes was disclosed by comparative DFT analysis of the assumed hydrazone- and hydrazide intermediates with different values of LUMO energy associated with different conformation. The structures of the new compounds were established by IR and NMR spectroscopy, including HMQC, HMBC and DNOE measurements. 相似文献
3.
Wrackmeyer B Klimkina EV Milius W Bauer T Kempe R 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(11):3238-3251
The reaction of the 1,2-diselenolato-1,2-dicarba-closo-dodecaborane(12) dianion [1,2-(1,2-C(2)B(10)H(10))Se(2)](2-) with dichloromethane (CH(2)Cl(2) or CD(2)Cl(2)) in the presence of donor solvents gave 4,5-[1,2-dicarba-closo-dodecaborano(12)]-1,3-diselenacyclopentane, the title compound, which was characterized by X-ray structural analysis and NMR spectroscopy ((1)H, (11)B, (13)C, and (77)Se). In the presence of pyridine, opening of the icosahedron took place, and a zwitterionic intermediate was isolated and fully characterized in the solid state by X-ray diffraction and in solution by multinuclear magnetic resonance techniques. Although such types of intermediates, prior to deboronation of the ortho-carborane cage, have been proposed several times, this is first example for which the structure has been confirmed unambiguously. This intermediate possesses a nido structure and contains a 7,8-dicarba-nido-undecaborate(1-) anion and a boronium cation, the latter with two pyridine rings linked to the boron atom, which has been extruded from the cage. It was shown that this process is reversible as long as the deboronation is not complete. The formation of the intermediate is accompanied by deboronation, which leads to the 7,8-dicarba-nido-undecaborate(1-) anion. The latter was prepared independently by conventional routes from the title compound, isolated as crystalline material as the tetrabutyl ammonium salt, and characterized by X-ray structural analysis and multinuclear magnetic resonance spectroscopy ((1)H, (11)B, (13)C, and (77)Se). 相似文献
4.
Organoaluminum alkyls L1AlMe2 ( 1 ), L2AlMe2 ( 2 ) and L2AliBu2 ( 3 ) with O,C,O‐chelating ligands L1 and L2 [L1 = 2, 6‐(MeOCH2)2C6H3 and L2 = 2, 6‐(tBuOCH2)2C6H3] were prepared. The compounds have been characterized by elemental analysis, 1H, 13C, 27Al NMR spectroscopy and X‐ray diffraction analysis ( 3 ). Solution NMR studies indicated the four coordinated aluminum atom and dissociation/association dynamic process in solution of 1 – 3 . The X‐ray diffraction analysis of 3 showed that the aluminum atom is [4 + 1] coordinated with the trans‐trigonal bipyramidal geometry. The reactivity of 2 was investigated. Reactions of 2 with MeOH and I2 resulted in aluminum alkoxide [L2Al(OMe)2 ( 4 )] and iodides [L2AlI2· THF ( 5 ) and L2AlI2 ( 6 )], respectively, characterized by elemental analysis, IR and 1H, 13C and 27Al NMR spectroscopy. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
5.
Gönül Yenilmez Çiftçi Hakan Dal Esra Tanrıverdi Eçik Tuncer Hökelek Adem Kılıç Elif Şenkuytu 《Polyhedron》2010
In this study, the crystal structures of the dispiroansa spermine derivatives of cyclotriphosphazene are characterised for the first time. The reaction of spiro-, gem-disubstituted cyclotriphosphazene derivatives, N3P3Cl4R2 [R = NHPh, (HN(CH2)3NH)0.5, (OCH2C(CH3)2CH2O)0.5], (1–3), with spermine (4), in aprotic solvents such as CH2Cl2 results in a series of dispirobino spermine derivatives of cyclotriphosphazene (5a, 6a, 7), namely spermine bridged compounds. Whereas, in protic solvents such as CHCl3 give, dispiroansa derivatives (8–10) namely tetracyclic cyclotriphosphazene. The new series of dispirobino and dispiroansa spermine derivatives of cyclotriphosphazene (5a, 6a, 7–10) have been characterised by elemental analysis, mass spectrometry, X-ray (for 5a, 8, 10) and 1H, 31P NMR spectroscopies. 相似文献
6.
《Magnetic resonance in chemistry : MRC》2003,41(3):183-192
1H and 13C NMR spectra of symmetrically substituted cyclotriphosphazenes exhibit second‐order effects. The influence of the 31P,31P coupling constants between ring phosphorus atoms on these effects was studied. Some values of this coupling constant between phosphorus bearing identical substituents were measured using 13C satellites of the 31P signals or by introduction of a chiral substituent on the third phosphorus atom. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
7.
O. V. Alebastrov V. A. Raldugin I. Yu. Bagryanskaya Yu. V. Gatilov M. M. Shakirov A. T. Kulyjasov S. M. Adekenov 《Russian Chemical Bulletin》2003,52(6):1449-1451
A new trichlorometoxy derivative of achillin was isolated from the mixture of chlorination products of achillin in MeOH. The structure of this product was established by X-ray diffraction analysis. This confirmed the previously proposed stereochemistry for the molecules of other two products of this reaction. 相似文献
8.
A density functional study at the BP86/AE1 level is presented for the cobalt bis(dicarbollide) ion [3-Co-(1,2-C2B9H11)2]- (1) and selected isomers and rotamers thereof. Rotation of the two dicarbollide moieties with respect to each other is facile, as judged by the small energetic separation of the three rotamers located (within 11 kJ mol(-1)) and by the low barriers for their interconversion (at most 41 kJ mol(-1)). Among the isomers differing in carbon atom positions that contain two equivalent dicarbollide ligands, the 1,7 ("carbon apart") form [2-Co-(1,7-C2B9H11)2]- is the most stable, 121 kJ mol(-1) below 1. The electronic structure of 1 is characterized in terms of molecular orbitals, population analysis, and excitation energies from time-dependent density functional theory, relevant to UV/Vis spectroscopy. Experimental 11B NMR chemical shifts of 1 are reproduced to better than 5 ppm at the GIAO-B3LYP/II' level, and the computed delta(11B) values are only little affected by rotational averaging or the presence of a polarizable continuum. Larger such effects are found for the as-yet unknown 59Co chemical shift, for which a value in the range between -1800 and -2400 ppm is predicted. Even though the accuracy achieved for the theoretical delta(11B) values is somewhat lower than that for heteroboranes at conventional ab initio levels, the level of density functional employed can afford qualitatively reliable chemical shifts, which can be useful in assignments and structural refinements of heteroboranes containing transition metal. 相似文献
9.
M. Yu. Lezhneva E. E. Schultz I. Yu. Bagryanskaya Yu. V. Gatilov M. M. Shakirov G. A. Tolstikov S. M. Adekenov 《Chemistry of Natural Compounds》2006,42(2):186-188
The bromination of betulin with bromine was descibed. The reaction in chloroform proceeded smoothly to form 29,30-dibromoallobetulin
in 80% yield.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 153–155, March–April, 2006. 相似文献
10.
Dr. Ahmad Masarwa Dr. Dennis Gerbig Liron Oskar Prof. Dr. Aharon Loewenstein Dr. Hans Peter Reisenauer Prof. Dr. Philippe Lesot Prof. Dr. Peter R. Schreiner Prof. Dr. Ilan Marek 《Angewandte Chemie (International ed. in English)》2015,54(44):13106-13109
The determination of the absolute configuration of chiral molecules is at the heart of asymmetric synthesis. Here we probe the spectroscopic limits for chiral discrimination with NMR spectroscopy in chiral aligned media and with vibrational circular dichroism spectroscopy of the sixfold‐deuterated chiral neopentane. The study of this compound presents formidable challenges since its stereogenicity is only due to small mass differences. For this purpose, we selectively prepared both enantiomers of 2H6‐ 1 through a concise synthesis utilizing multifunctional intermediates. While NMR spectroscopy in chiral aligned media could be used to characterize the precursors to 2H6‐ 1 , the final assignment could only be accomplished with VCD spectroscopy, despite the fleetingly small dichroic properties of 1 . Both enantiomers were assigned by matching the VCD spectra with those computed with density functional theory. 相似文献
11.
2‐Styrylchromones, although scarce in nature, constitute a group of oxygen heterocyclic compounds which have shown significant biological activities. New nitro‐2‐styrylchromones have been synthesised by the Baker–Venkataraman method, and the structure elucidation was accomplished using extensive 1D (1H, 13C) and 2D NMR spectroscopic studies (COSY, HSQC and HMBC experiments). Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
12.
Fabiana De C. Fim Tiago Machado Denise Santos De Sá Paolo R. Livotto Zênis N. Da Rocha Nara R. De S. Basso Griselda Barrera Galland 《Journal of polymer science. Part A, Polymer chemistry》2008,46(11):3830-3841
A novel complex dichlorobis(2‐ethyl‐3‐hydroxy‐4‐pyrone)zirconium(IV) (ZrCl2(ethylpyrone)2) was synthesized. Complexation of the pyrone ligand to the zirconium was confirmed by UV, 1H and 13C‐NMR, and electrochemical studies. NMR showed the presence of four isomers and density functional theory calculations indicated that the main isomer had a cis configuration. The catalyst was shown to be active in ethylene polymerization in the presence of the cocatalyst methylaluminoxane. The highest catalyst activity for the zirconium complex was achieved at Al/Zr = 2500, 70 °C and when a small concentration of catalyst was used (1 μmol). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3830–3841, 2008 相似文献
13.
Pascal Palmas Coralie Nyffenegger Eric Pasquinet Gérald Guillaumet 《Magnetic resonance in chemistry : MRC》2009,47(9):752-756
Mesomeric heteropentalene betaines are conjugated fused polyheterocyclic structures that represent interesting intermediates for organic synthesis. Five such structures, containing at least four nitrogen atoms and various substituents, have been characterized by 1H, 13C and 15N NMR. We report, apparently for the first time, nitrogen NMR data and coupling information on such systems. Inter‐ring long‐range correlations across five bonds with 15N (5JHN) and up to seven bonds with 13C (6JHC and 7JHC) were observed in HSQC experiments. The incorporation of an electron‐withdrawing substituent such as NO2 was observed to cause an increase in the magnitude of the remote couplings and deshielding of nearby protons, carbons and on all nitrogen atoms of the structure, including remote ones situated on other cycles. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
14.
Long‐Lived Excited States of Zwitterionic Copper(I) Complexes for Photoinduced Cross‐Dehydrogenative Coupling Reactions
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Dr. Bin Wang Dr. Deepak Prakash Shelar Xian‐Zhu Han Ting‐Ting Li Dr. Xiangguo Guan Prof. Dr. Wei Lu Dr. Kun Liu Prof. Dr. Yong Chen Prof. Dr. Wen‐Fu Fu Prof. Dr. Chi‐Ming Che 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(3):1184-1190
Four heteroleptic copper(I) complexes containing phenanthroline and monoanionic nido‐carborane‐diphosphine ligands have been prepared and structurally characterized by various spectroscopic techniques and X‐ray diffraction. These complexes exhibit intense absorptions in the visible range and excited‐state lifetimes on the microsecond scale. Their application in visible‐light‐induced cross‐dehydrogenative coupling reactions was investigated. Preliminary studies showed that one of the four copper(I) complexes is an efficient catalyst for photoinduced oxidative C?H functionalization using oxygen as oxidant. Furthermore, α‐functionalized tertiary amines were obtained in good‐to‐excellent yields by light irradiation (λ>420 nm) of a mixture of our CuI complex, tertiary amines, and a variety of nucleophiles (nitroalkane, acetone, or indoles) under aerobic conditions. Electron paramagnetic resonance measurements provided evidence for the formation of superoxide radical anions (O2??) rather than singlet oxygen (1O2) during these photocatalytic reactions. 相似文献
15.
Unique Stereocontrol in Carborane Chemistry: Skeletal Alkylcarbonation (SAC) versus Exoskeletal Alkylmethylation (EAM) Reactions
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Dr. Mario Bakardjiev Dr. Josef Holub Dr. Jan Macháček Dr. Drahomír Hnyk Prof. Dr. Bohumil Štíbr Dr. Zdeňka Růžičková Prof. Dr. Aleš Růžička 《Angewandte Chemie (International ed. in English)》2015,54(16):4937-4940
Reactions between the arachno‐6,9‐C2B8H14 ( 1 ) dicarbaborane and acyl chlorides, RCOCl ( 2 ), are subject to stereocontrol that completely changes the nature of the reaction products. While most chlorides produce the 8‐R‐nido‐7,8,9‐C3B8H11 ( 3 ) tricarbollides (by skeletal alkylcarbonation=SAC), bulky RCOCls ( 2 ; where R=1‐adamantyl, 2 a ; 1‐mesityl, 2 b ; 9‐anthranyl, 2 c ; 1‐naphthyl, 2 d ) in 1,2‐dichloroethane (DCE) in the presence of triethylamine at 40–60 °C gave a series of entirely different 1‐R‐2‐CH3‐closo‐1,6‐C2B8H8 ( 4 ) dicarbaboranes upon acidification with conc. H2SO4 (by exosleletal alkylmehylation=EAM). Both types of reactions seem to proceed via a common [8‐R‐nido‐7,8,9‐C3B8H10]? ( 3? ) anion which in the EAM case is unstable because of steric crowd and undergoes rearrangement via the isomeric [R‐nido‐7,8,10‐C3B8H10]? tricarbollide structures which, on protonation, undergo reductive extraction of one CH vertex to generate the 2‐CH3 substituent in structure 4 . 相似文献
16.
Yoshihiro Matano Prof. Tomonori Shinokura Kazuaki Matsumoto Hiroshi Imahori Prof. Haruyuki Nakano Prof. 《化学:亚洲杂志》2007,2(11):1417-1429
The synthesis and aggregation behavior of meso‐sulfinylporphyrins are described. The copper‐catalyzed C–S cross‐coupling reaction of a meso‐iodoporphyrin with benzenethiol and n‐octanethiol has proved to be an efficient method for the synthesis of meso‐sulfanylporphyrins, which are oxygenated by m‐chloroperbenzoic acid to produce the corresponding meso‐sulfinylporphyrins. Optically active zinc meso‐sulfinylporphyrins were successfully isolated by means of optical resolution of the racemates on a chiral HPLC column. Zinc sulfinylporphyrins readily undergo self‐organization through S–oxo–zinc coordination to form cofacial porphyrin dimers in solution, in which the hetero‐ and homodimers are present as a diastereomeric mixture. The aggregation modes of the S–oxo‐tethered porphyrin dimers were fully characterized by 1H NMR, IR, and UV/Vis spectroscopy as well as DFT calculations on their model compounds, thus revealing that the self‐aggregation behavior depends on the combination of S chirality. The absolute configurations at the sulfur center can be determined by the exciton‐coupled CD method. The observed self‐association constant for the S–oxo‐tethered dimerization of (S)‐phenylsulfinylporphyrin in toluene is larger than that in dichloromethane, which reflects the difference in dipole moments between the homodimer and the monomer. In cyclic and differential pulse voltammetry, the first oxidation process of the cofacial dimers is split into two reversible steps, which indicates that the initially produced π radical cations are delocalized efficiently between the two porphyrin rings. The present findings demonstrate the potential utility of meso‐sulfinyl groups as promising ligands for investigating the effects of peripheral chirality on the structures and optical and electrochemical properties of metal‐assisted porphyrin self‐assemblies. 相似文献
17.
Built-up macromolecules are acyclic molecules with molecular weights of several thousand daltons, which are synthesized by connecting small molecular units using stepwise methods. The chemical study of built-up macromolecules reveals some noteworthy properties that are different from those of conventional biological and synthetic macromolecules. A characteristic feature of built-up organic macromolecules is that their structures and properties are discontinuous at a certain molecular weight. For such macromolecules, variation in the small molecular units and the formation of cyclic structures substantially affect the structure and properties. The built-up organic macromolecules obtained by connecting helicenes with amide, acetylene, and amine groups are discussed in this paper. Some chiral built-up macromolecules are linked by covalent bonds, and the effects of linking on the structure are compared. 相似文献
18.
Rabinovich E Goldberg I Gross Z 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(44):12294-12301
Corrole complexes with gold(I) and gold(III) were synthesized and their structural, photophysical, and electrochemical properties investigated. This work includes the X-ray crystallography characterization of gold(I) and gold(III) complexes, both chelated by a corrole with fully brominated β-pyrrole carbon atoms. The mononuclear and chiral gold(I) corrole appears to be the first of its kind within the porphyrinoid family, while the most unique property of the gold(III) corrole is that it displays phosphorescence at ambient temperatures. 相似文献
19.
Diastereomeric mixtures of tricyclic 3-styrylpyrazolines have been prepared by the reaction of 3-cynnamylidenechroman-4-ones and their 1-thio analogs with hydrazine in hot acetic acid or propionic acid solutions. The diastereomeric mixtures were separated by column chromatography to obtain the pure diastereomers. The elucidation of their structure and stereochemistry and complete (1)H and (13)C assignments have been performed by a combination of various one- and two-dimensional NMR experiments. 相似文献
20.
D. A. Rudakov V. I. Potkin E. A. Dikusar P. V. Petrovskii I. B. Sivaev V. I. Bregadze 《Russian Chemical Bulletin》2007,56(5):922-925
Treatment of potassium 7,8-dimethyldecahydro-7,8-dicarba-nido-undecaborate with N-chloro-and N-bromosuccinimides in acetonitrile or with an excess of iodine in methanol gave the corresponding dihalo derivatives [9,11-X2-7,8-Me2-7,8-C2B9H8]− (X = Cl, Br, or I), which were isolated as alkylammonium salts. The compound (Me3NH)+[9,11-I2-7-Me-7,8-C2B9H9]− was synthesized by a reaction of K+[7-Me-7,8-C2B9H11]− with an excess of iodine in methanol. The compounds obtained were characterized by IR and NMR (1H, 11B, and 11B-11B COSY) spectroscopy.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 888–891, May, 2007. 相似文献