Indium(III) chloride forms in water with potassium 1,2‐dithiooxalate (dto) and potassium 1,2‐dithiosquarate (dtsq) stable coordination compounds. Due to the higher bridging ability of the 1,2‐dithiooxalate ligand in all cases only thiooxalate bridged binuclear complexes were found. From 1,2‐dithioquadratate with an identical donor atom set mononuclear trischelates could be isolated. Five crystalline complexes, (BzlMe3N)4[(dto)2In(dto)In(dto)2] ( 1 ), (BzlPh3P)4[(dto)2In(dto)In(dto)2] ( 2 ), (BzlMe3N)3[In(dtsq)3] ( 3 ), (Bu4N)3[In(dtsq)3] ( 4 ) and (Ph4P)[In(dtsq)2(DMF)2] ( 5 ), have been isolated and characterized by X‐ray analyses. Due to the type of the complex and the cations involved these compounds crystallize in different space groups with the following parameters: 1 , monoclinic in P21/c with a = 14.4035(5) Å, b = 10.8141(5) Å, c = 23.3698(9) Å, β = 124.664(2)°, and Z = 2; 2 , triclinic in P with a = 11.3872(7) Å, b = 13.6669(9) Å, c = 17.4296(10) Å, α = 88.883(5)°, β = 96.763(1)°, γ = 74.587(5)°, and Z = 1; 3 , hexagonal in R3 with a = 20.6501(16) Å, b = 20.6501(16) Å, c = 19.0706(13) Å and Z = 6; 4 , monoclinic in P21/c with a = 22.7650(15) Å, b = 20.4656(10) Å, c = 14.4770(9) Å, β = 101.095(5)°, and Z = 4; 5 , triclinic in P with a = 9.2227(6) Å, b = 15.3876(9) Å, c = 15.5298(9) Å, α = 110.526(1)°, β = 100.138(1)°, γ = 101.003(1)°, and Z = 2. 相似文献
In the present investigation, the first incorporation of both ferrocene scaffold and 1,2‐dihydro‐2‐oxopyridine‐3‐carbonitrile pharmacophore leading to a series of structurally novel ferrocene‐based hybrids has been achieved, involving the condensation reaction of ferrocenyl substituted chalcones with 2‐cyanoacetamide in a freshly prepared EtONa solution at 70°. The molecular structures of these newly synthesized products were confirmed by IR, and 1H‐ and 13C‐NMR analyses. 相似文献
(E)‐ and (Z)‐1,2‐bis(trifluoromethyl)ethene‐1,2‐dicarbonitrile ((E)‐ and (Z)‐BTE, resp., =(E)‐ and (Z)‐2,3‐bis(trifluoromethyl)but‐2‐enedinitrile) were used as a stereochemical probe in studying (2+2) cycloadditions of acceptor with donor alkenes. The additions to methyl (E)‐ and (Z)‐propenyl ether gave rise to the eight conceivable cyclobutanes 8 , although in different ratios in reactions of (E)‐ and (Z)‐BTE. The 19F‐NMR data served the structural assignment and the quantitative analysis. The mechanistic discussion is based on rotations and ring closures of the assumed 1,4‐zwitterionic intermediates. Dimethylketene dimethyl acetal, methylketene dimethyl acetal, and ketene diethyl acetal show an increasing rate in their reactions with BTE as well as in the equilibration of the cycloadducts. 相似文献
Engineering the surface of the metal clusters with the core structure maintained and tuning their luminescence in a wide range is still a challenge in the nanomaterial research. We modified six mono‐pyridyl ligands with different electronic effects (conjugation effect or induction effect) on a superatomic silver cluster [Ag14(C2B10H10S2)6(CH3CN)8] (denoted as Ag14) through in situ site‐specific surface engineering, and obtained the corresponding clusters [Ag14(C2B10H10S2)6(CH3CN)6(L1/L2)2] (denoted as NC‐1, 2, L1/L2 = 4‐acetylpyridine/ 4‐carboxypyridine) and [Ag14(C2B10H10S2)6(L3/L4/L5/L6)8] (denoted as NC‐3, 4, 5, 6, L3/L4/L5/L6 = 4‐phenylpyridine/4‐(1‐naphthyl)pyridine/9‐(4‐pyridine)anthracene/9‐(4‐pyridine)pyrene). Through the modification of the Ag14 cluster, a wide‐range luminescence from blue to red was realized. This work might provide a practical guide for improving the emission performance of metal clusters via surface engineering. 相似文献
The title compounds, 3,5,7‐triphenyl‐1,2‐diazacyclohepta‐1(7),2‐diene, C23H20N2, (I), and 3,7‐bis(2‐hydroxyphenyl)‐5‐phenyl‐1,2‐diazacyclohepta‐1(7),2‐diene, C23H20N2O2, (II), constitute the first structurally characterized examples of seven‐membered heterocycles with 1,2‐diaza ring N atoms. Compound (I) crystallizes in the space group P, with two independent molecules in the asymmetric unit that differ in the conformation of one of the phenyl rings, while (II) crystallizes in the space group C2/c. The C5N2 ring in each of (I) and (II) adopts a twist‐boat conformation. Compound (I) exhibits neither C—H...π interactions nor π–π stacking interactions, whereas (II) shows both intramolecular O—H...N hydrogen bonds and a C—H...π interaction that joins the molecules into an infinite chain in the [010] direction. 相似文献
The crystal structures of 1,2‐dimethyl‐3‐nitrobenzene, C8H9NO2, and 2,4‐dimethyl‐1‐nitrobenzene, C8H9NO2, which are liquids at room temperature, have been obtained through in‐situ cryocrystallization. Weak C—H...O and also π–π interactions are present in both crystal structures. 相似文献
The dehydrogenation reaction of a mixture of heptalene‐1,2‐ and heptalene‐4,5‐dimethanols 4a and 4b with basic MnO2 in AcOEt at room temperature led to the formation of the corresponding heptaleno[1,2‐c]furan‐1‐one 6a and heptaleno[1,2‐c]furan‐3‐one 7a (Scheme 2). Both products can be isolated by chromatography on silica gel. The methylenation of the furan‐3‐one 7a with 1 mol‐equiv. of Tebbe's reagent at ?25 to ?30° afforded the 2‐isopropenyl‐5‐methylheptalene‐1‐methanol 9a , instead of the expected 3,6‐dimethylheptaleno[1,2‐c]furan 8 (Scheme 3). Also, the treatment of 7a with Takai's reagent did not lead to the formation of 8 . On standing in solution at room temperature, or more rapidly on heating at 60°, heptalene 9a undergoes a reversible double‐bond shift (DBS) to 9b with an equilibrium ratio of 1 : 1. 相似文献
2,5‐Bis(chloromethyl)‐1,3,4‐oxadiazole was synthesized and dehydrohalogenation of this model compound was investigated under various base conditions. The formation of an intermediate with quinodimethane‐type structure is suggested for reaction in EtONa/EtOH. Polymerization of this intermediate proceeds via an anionic mechanism to form poly(1,3,4‐oxadiazole‐2,5‐diyl‐1,2‐vinylene). Polymerization at a toluene/water interface results in shorter polymerization times, milder conditions, higher molecular weights, higher yields and fewer defects in the polymer as compared to the corresponding polycondensation route.
A selective synthesis of 4‐methylthiosemicarbazide (=N‐methylhydrazinecarbothioamide; 4a ) derivatives by reaction with benzil (=1,2‐diphenylethane‐1,2‐dione; 3 ) is described. The reaction conditions determined the condensation product formed. The most important factor was the acid used: in the presence of conc. HCl solution, the open‐chain 2 : 1 compound 1a was exclusively obtained, whereas in the presence of 2M HCl, the cyclic 1 : 1 condensation product 2a was formed. The alcohol used, the presence of H2O, and the time of heating were additional crucial factors. The new cyclic compound 2a with a MeO group was exclusively formed when working under high‐dilution conditions. The reaction with the 4‐phenyl derivative 4b gave new cyclic compounds as the major products under all conditions used (Scheme). 相似文献
Crystals of hexa‐tert‐butyldisilane, C24H54Si2, undergo a reversible phase transition at 179 (2) K. The space group changes from Ibca (high temperature) to Pbca (low temperature), but the lattice constants a, b and c do not change significantly during the phase transition. The crystallographic twofold axis of the molecule in the high‐temperature phase is replaced by a noncrystallographic twofold axis in the low‐temperature phase. The angle between the two axes is 2.36 (4)°. The centre of the molecule undergoes a translation of 0.123 (1) Å during the phase transition, but the conformation angles of the molecule remain unchanged. Between the two tri‐tert‐butylsilyl subunits there are six short repulsive intramolecular C—H...H—C contacts, with H...H distances between 2.02 and 2.04 Å, resulting in a significant lengthening of the Si—Si and Si—C bonds. The Si—Si bond length is 2.6863 (5) Å and the Si—C bond lengths are between 1.9860 (14) and 1.9933 (14) Å. Torsion angles about the Si—Si and Si—C bonds deviate by approximately 15° from the values expected for staggered conformations due to intramolecular steric H...H repulsions. A new polymorph is reported for the crystal structure of 1,1,2,2‐tetra‐tert‐butyl‐1,2‐diphenyldisilane, C28H46Si2. It has two independent molecules with rather similar conformations. The Si—Si bond lengths are 2.4869 (8) and 2.4944 (8) Å. The C—Si—Si—C torsion angles deviate by between −3.4 (1) and −18.5 (1)° from the values expected for a staggered conformation. These deviations result from steric interactions. Four Si—C(t‐Bu) bonds are almost staggered, while the other four Si—C(t‐Bu) bonds are intermediate between a staggered and an eclipsed conformation. The latter Si—C(t‐Bu) bonds are about 0.019 (2) Å longer than the staggered Si—C(t‐Bu) bonds. 相似文献
A new class of poly(benzyl ether) dendrimers, decorated in their cores with N‐Boc‐protected 1,2‐diphenylethylenediamine groups, were synthesized and fully characterized. It was found that the gelation capability of these dendrimers was highly dependent on dendrimer generation, and the second‐generation dendrimer (R,R)‐G2DPENBoc proved to be a highly efficient organogelator. A number of experiments (SEM, TEM, FTIR spectroscopy, 1H NMR spectroscopy, rheological measurements, UV/Vis absorption spectroscopy, CD, and XRD) revealed that these dendritic molecules self‐assembled into elastically interpenetrating one‐dimensional nanostructures in organogels. The hydrogen bonding, π–π, and solvophobic interactions were found to be the main driving forces for formation of the gels. Most interestingly, these dendritic organogels exhibited smart multiple‐stimulus‐responsive behavior upon exposure to environmental stimuli such as temperature, anions, and mechanical stress. 相似文献
A one‐pot method for the synthesis of 3‐amino‐7‐nitro‐1,2‐dihydroisoquinoline‐4‐carbonitriles from 2‐chloro‐5‐nitrobenzylamines and malononitrile has been developed. 相似文献
A series of pyrimido[1,2‐a]benzimidazoles were obtained from aldehydes, 2‐aminobenzimidazole and ethyl acetoacetate in good‐to‐excellent yields by a simple, mild, and efficient procedure utilizing N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide (TBBDA) and poly(N‐bromo‐N‐ethylbenzene‐1,3‐disulfonamide) (PBBS) as catalysts. 相似文献