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141.
Two‐electron reduction of 1,1′‐bis(o‐carborane) followed by reaction with [Ru(η‐mes)Cl2]2 affords [8‐(1′‐1′,2′‐closo‐C2B10H11)‐4‐(η‐mes)‐4,1,8‐closo‐RuC2B10H11]. Subsequent two‐electron reduction of this species and treatment with [Ru(η‐arene)Cl2]2 results in the 14‐vertex/12‐vertex species [1‐(η‐mes)‐9‐(1′‐1′,2′‐closo‐C2B10H11)‐13‐(η‐arene)‐1,13,2,9‐closo‐Ru2C2B10H11] by direct electrophilic insertion, promoted by the carborane substituent in the 13‐vertex/12‐vertex precursor. When arene=mesitylene (mes), the diruthenium species is fluxional in solution at room temperature in a process that makes the metal–ligand fragments equivalent. A unique mechanism for this fluxionality is proposed and is shown to be fully consistent with the observed fluxionality or nonfluxionality of a series of previously reported 14‐vertex dicobaltacarboranes.  相似文献   
142.
The first dimesitylboryl substitution of aryl halides with a silylborane bearing a dimesitylboryl group in the presence of alkali‐metal alkoxides is described. The reactions of aryl bromides or iodides with Ph2MeSi?BMes2 and Na(OtBu) afforded the desired aryl dimesitylboranes in good to high yields and with high borylation/silylation ratios. Selective reaction of the sterically less‐hindered C?Br bond of dibromoarenes provided monoborylated products. This reaction was used to rapidly construct a D‐π‐A aryl dimesityl borane with a non‐symmetrical biphenyl spacer.  相似文献   
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2-Phenyl-3-thioformylindolizine and 1,2-dimethyl-3-thioformylindolizine undergo a novel desulfur coupling reaction in the presence of tributylphosphine to give (E)-1,2-bis(3-indolizinyl)ethenes in high yields. The structures of products were confirmed by IR, ^1H NMR, MS, elemental analysis and single crystal X-ray diffraction analysis. The mechanisms involved in various stages of the reaction were discussed.  相似文献   
145.
A study was carried out on the oxidative cyclocondensation of 2-thioxothieno-and 2-thioxopyrido[2,3-d]pyrimidin-4-ones. The thiophene ring with excess π-electron density facilitates the reaction, while the pyridine ring with diminished π-electron density hinders it. 2-Thioxothieno-[2,3-d]pyridimin-4-ones were converted into previously unreported 7H,13H-[1,2,4]thiadiazolo-[3,2-b:5,4-b′]bis(thieno[2,3-d]pyridimine-7,13-diones). __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1424–1427, September, 2007.  相似文献   
146.
The conditions for the thermolysis of furoxans annulated with differently strained five-membered carbocycles (cyclopentafuroxan 1, norbornenofuroxan 2, and acenaphthofuroxan 3) to bis(nitrile oxides) in the presence of various dipolarophiles (diethyl acetylenedicarboxylate, benzoylformonitrile, and ethoxycarbonylformonitrile) were optimized. It was found that the reactivities of the above furoxans as sources of bis(nitrile oxides) decrease in the order 2 > 1 > 3. Among the furoxans studied, only norbornenofuroxan 2 can be recommended as a possible cross-linking reagent for polymers. The formation of di-N-oxides of 3,4-bis(cyanopropyl)-, 3,4-bis(cyanocyclopentyl)-, and 3,4-bis(cyanonaphthyl)furoxans was detected. They resulted from intermolecular cyclodimerization of bis(nitrile oxides) initially formed in the thermolysis of furoxans 13. Dedicated to Academician V. A. Tartakovsky on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1521–1528, August, 2007.  相似文献   
147.
Using 1H NMR spectroscopy and steady-state and time-resolved electronic spectroscopy, the optical properties of mono-and bis(styryl)pyridinium perchlorates and their complexes with Mg2+, Ba2+ cations were studied. The stability constants of the complexes were determined using spectrophotometric titration. The formation of inclusion complexes for Mg2+ and sandwich type complexes for Ba2+ results in fluorescence enhancement and increases the lifetimes of the excited states of the initial bis-styryl ligands. The variation of position of the styryl fragment in the pyridinium aromatic ring gives rise to photochromic crown ethers with different optical and photophysical characteristics and is also an easy route to bis(crown-ethers) of symmetrical and unsymmetrical structure. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2092–2100, November, 2007.  相似文献   
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Coordination polymers (CPs) built by coordination bonds between metal ions/clusters and multidentate organic ligands exhibit fascinating structural topologies and potential applications as functional solid materials. The title coordination polymer, poly[diaquabis(μ4‐biphenyl‐3,4′,5‐tricarboxylato‐κ4O3:O3′:O4′:O5)tris[μ2‐1,4‐bis(1H‐imidazol‐1‐yl)benzene‐κ2N3:N3′]dicopper(II)dicopper(I)], [CuII2CuI2(C15H7O6)2(C12H10N4)3(H2O)2]n, was crystallized from a mixture of biphenyl‐3,4′,5‐tricarboxylic acid (H3bpt), 1,4‐bis(1H‐imidazol‐1‐yl)benzene (1,4‐bib) and copper(II) chloride in a water–CH3CN mixture under solvothermal reaction conditions. The asymmetric unit consists of two crystallographically independent Cu atoms, one of which is CuII, while the other has been reduced to the CuI ion. The CuII centre is pentacoordinated by three O atoms from three bpt3− ligands, one N atom from a 1,4‐bib ligand and one O atom from a coordinated water molecule, and the coordination geometry can be described as distorted trigonal bipyramidal. The CuI atom exhibits a T‐shaped geometry (CuN2O) coordinated by one O atom from a bpt3− ligand and two N atoms from two 1,4‐bib ligands. The CuII atoms are extended by bpt3− and 1,4‐bib linkers to generate a two‐dimensional network, while the CuI atoms are linked by 1,4‐bib ligands, forming one‐dimensional chains along the [20] direction. In addition, the completely deprotonated μ4‐η1111 bpt3− ligands bridge one CuI and three CuII cations along the a (or [100]) direction to form a three‐dimensional framework with a (103)2(10)2(42.6.102.12)2(42.6.82.10)2(8) topology via a 2,2,3,4,4‐connected net. An investigation of the magnetic properties indicated a very weak ferromagnetic behaviour.  相似文献   
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