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1.
The review concerns the synthesis, structure, and chemical transformations of mercury derivatives of various polyhedral boron hydrides (carboranes, metallacarboranes, and boranes) and covers a period of time since the pioneering studies of Prof. V. I. Bregadze on chemistry of C- and B-substituted derivatives of icosahedral carboranes C2B10H12 up to date. The emphasis is placed on recent results obtained in this field, in particular, Hg-promoted substitution in nido-carboranes as well as the synthesis and properties of mercury derivatives of monocarbon carborane anion [CB11H12]–.
相似文献2.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(30):8768-8772
Direct nucleophilic substitution reaction of cage B−H bonds of o ‐carboranes by Grignard reagents in the absence of any transition metals has been achieved for the first time, and leads to the regioselective synthesis of a series of 4‐alkyl‐1,2‐diaryl‐o ‐carboranes in very high yields. The presence of two electron‐withdrawing aryl groups on the cage carbon atoms is crucial to realizing the reaction. The regioselectivity is controlled by both electronic and steric factors. This work represents a new strategy for the development of methods for carborane functionalization. 相似文献
3.
The chemistry of boron clusters has been dominated by icosahedral carboranes for over half a century. Only in recent years has significant progress been made in the chemistry of supercarboranes (carboranes with more than 12 vertices). A number of CAd (carbon‐atoms‐adjacent) 13‐ and 14‐vertex carboranes, and CAp (carbon‐atoms‐apart) 13‐vertex carboranes as well as their corresponding 14‐ and 15‐vertex metallacarboranes have been successfully prepared and structurally characterized. This breakthrough relied on the use of CAd nido‐carborane dianions as starting materials. These supercarboranes can undergo single‐electron reduction to give stable supercarborane radical monoanions with [2n+3] framework electrons, and electrophilic substitution reaction to afford hexasubstituted supercarboranes. They can react with nucleophiles to offer monocarba‐closo‐dodecaborate monoanions from cage‐carbon extrusion reactions. Their unique chemical properties make the chemistry of supercarboranes distinct from that of their 12‐vertex analogues. These studies open up new possibilities for the development of polyhedral clusters of extraordinary size. This focus review offers an overview of recent advances in this growing research field. 相似文献
4.
Based on general principles of quantum theory of chemical transformations for polyatomic molecules, the notion of the reaction
center (RC) was revised. The presence of RCs is a necessary condition for occurrence of all types of chemical transformations
in complex systems. The physical picture of processes in RCs, conditions for maximum probability of transformations, the local
character of a chemical reaction and its relation to the characteristic vibrations, and the methods of a priori search for RCs based on normal coordinate analysis of coupled states and on calculations of overlap integrals between vibrational
wave functions were studied. Specific features of manifestation of characteristic vibrations in vibrational and vibronic spectra
were investigated and the possibility of search for RCs using optical spectroscopy was considered.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1267–1273, August, 2006. 相似文献
5.
Valentina Uivarosi Mihaela Badea Rodica Olar Dana Marinescu Teodor Octavian Nicolescu George Mihai Nitulescu 《Journal of Thermal Analysis and Calorimetry》2011,105(2):645-650
Three new complexes with ligands belong to the fluoroquinolone class having the general formula [RuL2Cl2]Cl nH2O ((1) L: norfloxacin (nf), n = 4; (2) L: ciprofloxacin (cp), n = 3; (3) L: enrofloxacin (enro), n = 5) were synthesized and characterized by chemical analysis UV–Vis and IR spectroscopy. In all complexes fluoroquinolone
derivative acts as bidentate chelate ligand. The thermal behavior steps were investigated in synthetic air flow. The thermal
transformations are complex processes according to TG and DTG curves including dehydration, quinolone derivative degradation,
as well as RuCl3 conversion in RuO2. 相似文献
6.
Mihaela Badea Rodica Olar Dana Marinescu Valentina Uivarosi Daniela Iacob 《Journal of Thermal Analysis and Calorimetry》2009,97(2):735-739
A series of new complexes with mixed ligands of the type RuL2(DMSO)
m
Cl3·nH2O ((1) L: norfloxacin (nf), m = 1, n = 1; (2) L: ciprofloxacin (cp), m = 2, n = 2; (3) L: ofloxacin (of), m = 1, n = 1; (4) L: enrofloxacin (enro), m = 0.5, n = 4; DMSO: dimethylsulfoxide) were synthesised and characterised by chemical analysis and IR data. In all complexes both
fluoroquinolone derivative and DMSO act as unidentate. The thermal behaviour steps were investigated in synthetic air flow.
The thermal transformations are complex processes according to TG and DTG curves including dehydration, quinolone derivative
and DMSO degradation respectively. The final product of decomposition is ruthenium (IV) oxide. 相似文献
7.
Junxia Li Ronglin Pang Zhifang Li Guoqiao Lai Xu‐Qiong Xiao Thomas Müller 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(5):1411-1415
The synthesis of a series of 1,2‐diamino‐o‐carboranes ( 1 – 4 ) is reported. The molecular structures of these diamino‐o‐carboranes are remarkable as the inner‐cluster C?C bonds are all ultra‐long (162.7–193.1 pm) and vary substantially with small variations in the substituents. The results of quantum mechanical investigations suggest that the origin of the bond elongation is significant in‐plane negative hyperconjugation of lone pairs of the nitrogen substituents with the σ* orbitals of the C?C bonds in o‐carboranes. 相似文献
8.
The molecular and electronic structures and thermodynamic parameters of 1,2-, 1,7-, and 1,12-dicarba-closo-dodecaborane(12) molecules in the singlet ground state were calculated by the Hartree-Fock, DFT, and MP2 (including B3LYP/6-311G(2d,2p)
and MP2/6-311+G(d,2p) methods). The energies and character of spatial localization of the frontier MOs in o-, m-, p-carboranes(12) correlate with the changes in the configuration stabilities and reactivities in the reactions of carboranes
with electrophilic and nucleophilic agents and bases. The electrostatic potential distributions in the molecules and the atomic
charge distribution of hydrogen atoms correlate with the known chemical properties of carboranes(12). The thermodynamic parameters
of two isomerization reactions, o-C2B10H12 ⇌ m-C2B10H12 and m-C2B10H12 ⇌ p-C2B10H12, calculated for the temperature range 298–1000 K agree with experimental data within the limits of measuring error. The values
of the electron density and the Laplacian of the electron density at the (3, −1) critical points of the B-H and C-H bonds
correlate with the reactivities of the title compounds.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2074–2080, December, 2006. 相似文献
9.
Crystal Structures of the Carborane Dianions [1,4‐(PhCB10H10C)2C6H4]2− and [1,4‐(PhCB10H10C)2C6F4]2− and the Stabilizing Role of the para‐Phenylene Unit on 2 n+3 Skeletal Electron Clusters 下载免费PDF全文
Dr. Jan Kahlert Dr. Hans‐Georg Stammler Beate Neumann Dr. Rachel A. Harder Prof. Dr. Lothar Weber Dr. Mark A. Fox 《Angewandte Chemie (International ed. in English)》2014,53(14):3702-3705
While carboranes with 2 n+2 and 2 n+4 (n=number of skeletal atoms) skeletal electrons (SE) are widely known, little has been reported on carboranes with odd SE numbers. Electrochemical measurements on two‐cage assemblies, where two C‐phenyl‐ortho‐carboranyl groups are linked by a para‐phenylene or a para‐tetrafluorophenylene bridge, revealed two well separated and reversible two‐electron reduction waves indicating formation of stable dianions and tetraanions. The salts of the dianions were isolated by reduction with sodium metal and their unusual structures were determined by X‐ray crystallography. The diamagnetic dianions contain two 2 n+3 SE clusters where each cluster has a notably long carborane C–carborane C distance of ca 2.4 Å. The π conjugation within the phenylene bridge plays an important role in the stabilization of these carboranes with odd SE counts. 相似文献
10.
Yasuyuki Endo Kiminori Ohta Tomohiro Yoshimi Kentaro Yamaguchi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4-5):799-802
The inorganic cage compounds, dicarba-closo-dodecaboranes (carboranes), are chemical building blocks of remarkable thermal and chemical stability, with spherical geometry and exceptional hydrophobic character. We have focused on medicinal drug design using carboranes as a hydrophobic pharmacophore and have developed a potent estrogen agonist, BE120. We also have applied carboranes for structural chemistry, utilizing their specific three-dimensional character to obtain multilayer aromatic structures. 相似文献
11.
Miroslav Janata Petr Vlček Petra Látalová Romana Svitáková Jiří Kaleta Michal Valášek Victoria Volkis Josef Michl 《Journal of polymer science. Part A, Polymer chemistry》2011,49(9):2018-2023
Radical polymerization of selected 1‐alkenes, (1‐hexene, 1‐octene and 2‐methyl‐1‐heptene), initiated with classical radical initiators and catalyzed by lithium salts of selected carboranes was studied. In accordance with recently published results it was found that the use of radical initiators under catalysis by “naked” lithium cation of carboranes promotes the radical polymerization of 1‐alkenes, otherwise nonpolymerizable by the radical mechanism. However, although in our experiments relatively high monomers conversions are reached for some of the thermal initiators used, only low‐molecular‐weight oligomers with Mn < 1000 are formed, regardless of the initiator and carborane anion used. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
12.
13.
Vincent Terrasson Dr. José Giner Planas Dr. Damien Prim Prof. Francesc Teixidor Prof. Dr. Clara Viñas Prof. Dr. Mark E. Light Dr. Michael B. Hursthouse Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(44):12030-12042
The convenient synthesis of original aminobenzyl‐o‐carboranes, which represent a new class of nitrogenated carborane derivatives, is described. These novel compounds have been efficiently prepared starting from commercially available aromatic aldehydes and monosubstituted o‐carboranes via carboranyl alcohols and chlorides as intermediates. The key step of this methodology is a selective nucleophilic amination under mild conditions that allows the formation of the expected amines while limiting the partial deboronation of the carborane cluster. This general strategy has been applied to the preparation of a wide variety of aminobenzyl‐o‐carboranes. The extension of this pathway to the synthesis of enantiopure carborane–amine combinations is also described. 相似文献
14.
Facial Synthesis of o‐Carborane‐Substituted Alkenes and Allenes by a Regioselective Ene Reaction of 1,3‐Dehydro‐o‐carborane 下载免费PDF全文
Da Zhao Jiji Zhang Prof.Dr. Zuowei Xie 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10334-10337
1,3‐Dehydro‐o‐carborane is a useful synthon for selective cage boron functionalization of o‐carboranes. It reacts readily with alkenes or alkynes to give a variety of cage B(3)‐alkenyl/allenyl o‐carboranes by ene reactions in very high yields and excellent regioselectivity. This can be ascribed to the highly polarized cage C?B multiple bond, which lowers the activation barriers of the ene reaction. 相似文献
15.
《Solid State Sciences》2012,14(6):730-734
Zircon ore carbothermal reduction with yttria addition has been carried out. The influences of heating temperature and yttria addition on the phase transformations of zirconia from zircon ore by carbothermal reduction have been investigated in detail. The phase transformations of zirconia from zircon ore by carbothermal reduction were monitored by X-ray diffraction. The microstructure and micro-area chemical analysis of the products were characterized by scanning electron microscopy and energy dispersive spectrometer. The chemical states of Zr 3d, Y 3d and O 1s presented in the products of zircon carbothermal reduction with 10 wt% yttria addition were investigated by X-ray photoelectron spectroscopy. The results showed that the optimized heating temperature of zircon carbothermal reduction with no addition was 1600 °C, and the main phase of the products consists of m-ZrO2, c-ZrO2, ZrC and β-SiC. Yttria addition could be introduced into zirconia lattice and caused it to form Y2O3 stabilized zirconia. Zirconia in the products would be turned into partially stabilized zirconia with yttria addition from 1 wt% to 5 wt% while it would exist in the form of fully stabilized zirconia with over 8 wt% yttria addition. 相似文献
16.
Orazio Nicolotti Ilenia Giangreco Teresa Fabiola Miscioscia Marino Convertino Francesco Leonetti Leonardo Pisani Angelo Carotti 《Journal of computer-aided molecular design》2010,24(2):117-129
Abstract
A series of 27 benzamidine inhibitors covering a wide range of biological activity and chemical diversity was analysed to derive a Linear Interaction Energy in Continuum Electrostatics (LIECE) model for analysing the thrombin inhibitory activity. The main interactions occurring at the thrombin binding site and the preferred binding conformations of inhibitors were explicitly biased by including into the LIECE model 10 compounds extracted from X-ray solved thrombin-inhibitor complexes available from the Protein Data Bank (PDB). Supported by a robust statistics (r 2 = 0.698; q 2 = 0.662), the LIECE model was successful in predicting the inhibitory activity for about 76% of compounds (r ext2 ≥ 0.600) from a larger external test set encompassing 88 known thrombin inhibitors and, more importantly, in retrieving, at high sensitivity and with better performance than docking and shape-based methods, active compounds from a thrombin combinatorial library of 10240 mimetic chemical products. The herein proposed LIECE model has the potential for successfully driving the design of novel thrombin inhibitors with benzamidine and/or benzamidine-like chemical structure. 相似文献17.
Rhodium‐Catalyzed Regioselective Hydroxylation of Cage B−H Bonds of o‐Carboranes with O2 or Air 下载免费PDF全文
Hairong Lyu Dr. Yangjian Quan Prof. Dr. Zuowei Xie 《Angewandte Chemie (International ed. in English)》2016,55(39):11840-11844
A rhodium‐catalyzed hydroxylation of a cage B4?H bond in o‐carboranes with either O2 or air as the oxygen source is described, and serves as a new methodology for the regioselective generation of a series of 4‐OH‐o‐carboranes in a one‐pot process. The use of either O2 or air as both the oxidant and the oxygen source makes this protocol very environmentally friendly and practical. 相似文献
18.
Rizwan Shukat Claudie Bourgaux Perla Relkin 《Journal of Thermal Analysis and Calorimetry》2012,108(1):153-161
Four emulsions were prepared using high pressure homogenisation at 300 or 1200 bar and aqueous phases containing 4.5 wt% whey
proteins in mixture with 20 wt% palm oil (PO), alone (E300 and E1200), or in which 20 wt% PO was replaced by vitamin (EV300,
EV1200). Thermal behaviour of bulk fat and emulsions in the absence or presence of vitamin, as monitored by differential scanning
calorimetry (DSC), indicated that fat crystallisation in supercooled melt was delayed in bulk fat in the presence of vitamin
and more delayed in emulsions with lower droplet sizes and containing vitamin. These results were supported by (i) isothermal
DSC experiments where exothermic peaks occurred at higher holding times and (ii) dynamic DSC experiments which showed lower
melting reactions in emulsions with lower droplet sizes and containing vitamin. Synchrotron X-ray scattering measurements
performed simultaneously at small and wide angles on fat samples stored at 4 °C for 12 h showed co-existence of 2L and 3L longitudinal stacking in bulk fat without vitamin, and only 2L organisation of TAGs in the presence of vitamin. Trends in the proportions of α,
β′, β lateral packing in lipid droplets were also observed to be more affected by the presence of vitamin rather than their size,
indicating a higher rate of α → β′ → β polymorphic transformations in the presence of vitamin. Combining data obtained from DSC and X-Ray signals showed that lipid
droplets with lower solid fat content, of which a higher proportion of β polymporphs, were those presenting lower size and
lower ability for vitamin protection against chemical degradation, which is of great interest for formulation of lipid nanoparticles
as bioactive matrix carriers. 相似文献
19.
Nickel‐Catalyzed Cross‐Coupling Reactions of o‐Carboranyl with Aryl Iodides: Facile Synthesis of 1‐Aryl‐o‐Carboranes and 1,2‐Diaryl‐o‐Carboranes 下载免费PDF全文
Cen Tang Prof. Dr. Zuowei Xie 《Angewandte Chemie (International ed. in English)》2015,54(26):7662-7665
A nickel‐catalyzed arylation at the carbon center of o‐carborane cages has been developed, thus leading to the preparation of a series of 1‐aryl‐o‐carboranes and 1,2‐diaryl‐o‐carboranes in high yields upon isolation. This method represents the first example of transition metal catalyzed C,C′‐diarylation by cross‐coupling reactions of o‐carboranyl with aryl iodides. 相似文献
20.
Alberto V. Puga Dr. Francesc Teixidor Prof. Dr. Reijo Sillanpää Prof. Dr. Raikko Kivekäs Dr. Massimiliano Arca Dr. Gemma Barberà Dr. Clara Viñas Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(38):9755-9763
The incorporation of iodine atoms onto the boron vertices of the o‐carborane framework causes, according to spectroscopic data, a uniform increase in the acidic character of the Cc? H (Cc= cluster carbon) vertices, whereas the incorporation of methyl groups onto the boron vertices of the o‐carborane framework reduces their acidity. Methyl groups when attached to boron are electron‐withdrawing in boron clusters, whereas iodine atoms bonded to boron act as electron donors. This has been proven on B‐methyl and B‐iodinated o‐carboranes with NMR spectroscopy measurements and DFT calculations of natural bond orbital (NBO) charges, which show a cumulative buildup of positive cluster‐only total charge (CTC) on B‐methyl o‐carboranes and a cumulative buildup of negative cluster‐only total charge for B‐iodinated o‐carboranes. 相似文献