Bicyclo[2.1.1]hexanes(BCHs) are structurally unique C(sp^(3))-rich bicyclic hydrocarbons that are gaining prominence in the field of medicinal chemistry as bioisosteres of benzenoids.The nitrile is an important functi...Bicyclo[2.1.1]hexanes(BCHs) are structurally unique C(sp^(3))-rich bicyclic hydrocarbons that are gaining prominence in the field of medicinal chemistry as bioisosteres of benzenoids.The nitrile is an important functionality in drug development due to its ability to improve physicochemical and pharmacokinetic properties and facilitate potential noncovalent interactions with drug targets.Consequently,cyanoarene motifs are commonly found in drug development.The introduction of cyano-BCHs as potential bioisosteres of cyano-arenes shows great promise;however,there are currently no catalytic methods available for their synthesis.Herein,we report a palladium-catalyzed enantioselective [2σ+2π] cycloadditions of bicyclo[1.1.0]butanes with arylidenemalononitriles for the preparation of chiral cyano-BCHs.This method accommodated a wide range of substrates and tolerated various functional groups.The cyano-BCH products could be transformed to molecules with diverse functionality.Control experiments suggest that the reaction proceeds via a zwitterionic intermediate generated by palladium-mediated ring opening of vinyl-carbonyl bicyclo[1.1.0]butanes followed by stereoselective 1,2-addition and intramolecular allylic substitution reactions.展开更多
The effects of rare earth（RE）on the structure,acidity,and catalytic performance of HZSM-5 zeolite were investigated.A series of RE/HZSM-5 catalysts,containing 7.54% RE（RE=La,Ce,Pr,Nd,Sm,Eu or Gd）,were prepared by ...The effects of rare earth（RE）on the structure,acidity,and catalytic performance of HZSM-5 zeolite were investigated.A series of RE/HZSM-5 catalysts,containing 7.54% RE（RE=La,Ce,Pr,Nd,Sm,Eu or Gd）,were prepared by the impregnation of the ZSM-5 type zeolites（Si/Al=64：1）with the corresponding RE nitrate aqueous solutions.The catalysts were characterized by means of FT-IR,UV-Vis,NH3-TPD,and IR spectroscopy of adsorbed pyridine.The catalytic performances of the RE/HZSM-5 for the catalytic cracking of mixed butane to light olefins were also measured with a fixed bed microreactor.The results revealed that the addition of light rare earth metal on the HZSM-5 catalyst greatly enhanced the selectivity to olefins,especially to propylene,thus increasing the total yield of olefins in the catalytic cracking of butane.Among the RE-modified HZSM-5 samples,Ce/HZSM-5 gave the highest yield of total olefins,and Nd/HZSM-5 gave the highest yield of propene at a reaction temperature of 600℃.The presence of rare earth metal on the HZSM-5 sample,not only modified the acidic properties of HZSM-5 including the amount of acid sites and acid type,that is,the ratio of L/B（Lewis acid/Brnsted acid）,but also altered the basic properties of it,which in turn promoted the catalytic performance of HZSM-5 for the catalytic cracking of butane.展开更多
Te-promoted （1%） vanadium phosphate catalyst （VPDTe） was prepared via VOPO4·2H2O by calcining its precursor VOHPO4·0.5H2O in a flow of n-butane/air.VPDTe catalyst has resulted a higher existence of V5＋ ...Te-promoted （1%） vanadium phosphate catalyst （VPDTe） was prepared via VOPO4·2H2O by calcining its precursor VOHPO4·0.5H2O in a flow of n-butane/air.VPDTe catalyst has resulted a higher existence of V5＋ phase with V5＋/V4＋ ratio of 0.23.SEM micrographs show that Te addition altered the arrangement of the platelets from ＂rose-like＂ clusters to layer with irregular shape.Te addition has also markedly lowered the reduction activation energies of the vanadium phosphate catalyst as revealed by TPR profile.The amount of active oxygen species associated with V4＋ phase of the Te promoted catalyst was significantly higher than those of the unpromoted catalyst.These observations suggest that high mobility and availability of reactive oxygen species contributed to the enhancement of n-butane conversion up to 80% at 673 K,while only 47% over unpromoted catalyst （2400 h^-1,1.7% n-butane in air）.展开更多
The title coordination polymer 1,{[Cu8（btb）2（CN）8].3H2O}n（btb = 1,4-bis（1,2,4-triazol-1-yl）butane）,has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex...The title coordination polymer 1,{[Cu8（btb）2（CN）8].3H2O}n（btb = 1,4-bis（1,2,4-triazol-1-yl）butane）,has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group C2/c with a = 1.2938（3）,b = 1.9422（5）,c = 0.9406（2） nm,β = 121.891（4）°,V = 2.0066（9） nm3,C24H30Cu8N20O3,Mr = 1155.00,Dc = 1.912 g/cm3,μ（MoKα） = 4.209 mm？1,F（000） = 1140,GOF = 1.184,Z = 2,the final R = 0.0634 and wR = 0.1503 for I 2σ（I）.In complex 1,one-dimensional CuCN zigzag chains are linked by triazolyl groups of btb ligands to form two-dimensional networks,which are further bridged by 1,4-butyl moieties of btb ligands to fabricate a three-dimensional order framework,in which one-dimensional ellipsoid-like channels are observed.展开更多
An efficient technology of impregnation of carbonate crushed stone by oil-product based on SCF-impregnation process usage with propane/butane solvent was developed. Regular impregnation throughout the volume of crushe...An efficient technology of impregnation of carbonate crushed stone by oil-product based on SCF-impregnation process usage with propane/butane solvent was developed. Regular impregnation throughout the volume of crushed stone sample is achieved. As a result of the appliance of proposed technology, the humidity of the treated crushed stone samples decreased down to 0.54%.展开更多
The oxidative dehydrogenation of butane to butadiene and butene was studied using a conventional fixed-bed ractor (FBR), inert membrane reactor (IMR) and mixed inert membrane reactor (MIMR). When IMR and MIMR were emp...The oxidative dehydrogenation of butane to butadiene and butene was studied using a conventional fixed-bed ractor (FBR), inert membrane reactor (IMR) and mixed inert membrane reactor (MIMR). When IMR and MIMR were employed, a ceramic membrane modified by partially coating with glaze was used to distribute oxygen to a fixed-bed of 24-V-Mg-O catalyst. The oxygen partial pressure in the catalyst bed could be decreased. The effect of feeding modes and operation conditions were investigated. The selectivity of C4 dehydrogenation products (butene and butadiene) was found to be higher in IMR than in FBR. The feeding mode with 20% of air mixing with butane in MIMR was found to be more efficient than the feeding mode with all air permeating through ceramic membrane. The MIMR gave the most smooth temperature profile along the bed.展开更多
Eight new macrocyclic complexes were synthesized by template reaction of 1,4-bis（3-aminopropoxy）butane with metal nitrate and 1,3-bis（2-formylphenyl）propane or 1,4-bis（2-formylphenyl）butane and their structures ...Eight new macrocyclic complexes were synthesized by template reaction of 1,4-bis（3-aminopropoxy）butane with metal nitrate and 1,3-bis（2-formylphenyl）propane or 1,4-bis（2-formylphenyl）butane and their structures were proposed on the basis of elemental analysis, FTIR, UV-vis, molar conductivity measurements, ^1H NMR and mass spectra. The metals to ligand molar ratios of the complexes were found to be 1： 1. The complexes are 1：2 electrolytes for Pb（II）, Zn（II） and Cd（II） complexes and 1：3 electrolytes for La（III） as shown by their molar conductivities （Am） in DMSO at 10^-3 mol L^-1. Due to the existence of free ions in these complexes, such complexes are electrically conductive. The configurations of La（III） and Pb（II） were proposed to probably octahedral and Zn（II） and Cd（II） complexes were proposed to probably tetrahedral.展开更多
The new ligand bis-（1,4-sodium thiolactate） butane （L）-O2CCH3S-（CH2）4SCHCH3CO2- has been prepared from the reaction of disodium salt of thiolactic acid and 1,4-dichlorobutane, while the disodium thiolactate was ...The new ligand bis-（1,4-sodium thiolactate） butane （L）-O2CCH3S-（CH2）4SCHCH3CO2- has been prepared from the reaction of disodium salt of thiolactic acid and 1,4-dichlorobutane, while the disodium thiolactate was prepared instanteously through the reaction of thiolactic acid with NaOH. Mono and dinuclear complexes were obtained by direct reaction of the above ligands with H[AuCI4] in 1 ： 1, 2：1, 1：2, 2：2 and 3：1 ligands to metal molar ratio. The prepared complexes were characterized by elemental analysis, spectral studies FTIR （Fourier transform Infrared） and UV-Vis, magnetic measurement, conductivity measurement and IHNMR for the ligand （L） and some of the complexes. The conductance data indicate that the complexes of the formulas Na[Au（SCH3CHCOO）2], Na[Au（SCH3CHCOO）（OOCCHCH3SH）2] and [Au（L）]Cl are 1：1 electrolyte. Electronic spectra and magnetic moment values indicate the presence of square planner geometry around Au（III） ions.展开更多
As the smallest fused hydrocarbon and one of the most strained carbocycles,bicyclo[1.1.0]butane(BCB)undergoes a wide array of strain-releasing transformations,thereby exhibiting a rich and varied chemical profile.Alth...As the smallest fused hydrocarbon and one of the most strained carbocycles,bicyclo[1.1.0]butane(BCB)undergoes a wide array of strain-releasing transformations,thereby exhibiting a rich and varied chemical profile.Although BCBs have been synthesized and studied for over 60 years,its potential as a versatile building block for expanding chemical space has remained largely underexplored.Recently,the emergence of diverse activation strategies,such as photocatalysis,boryl radical catalysis,Lewis/Bronsted acid catalysis,palladium catalysis,Lewis base catalysis,and radical relay strategies,has revolutionized BCB chemistry into a powerful toolbox for expanding the chemical space of scaffold-diverse molecules,with a particular focus on cyclobutane,cyclobutene,and bicyclo[n.1.1]alkane scaffolds.In this review,we highlight the latest advancements in the divergent transformations of BCBs to construct cyclobutyl-decorated architectures from common precursors,with a particular emphasis on elucidating the reaction mechanisms.The content is organized based on key regulatory factors for product divergent formation.It is anticipated that this review will stimulate increased interest among researchers in integrating the concept of controllable divergent synthesis into BCB chemistry.By doing so,it is expected to further unlock the potential of BCBs in expanding molecular space and to extend the reach of BCB chemistry into a wider array of synthetic applications.展开更多
Transition-metal-catalyzed radical-mediated four-component carbonylation reactions offer a sustainable and efficient strategy for modular synthesis of complex carbonyl compounds from simple feedstocks.However,current ...Transition-metal-catalyzed radical-mediated four-component carbonylation reactions offer a sustainable and efficient strategy for modular synthesis of complex carbonyl compounds from simple feedstocks.However,current studies have primarily focused on the alkylcarbonylation ofπ-bonds in unsaturated hydrocarbons,including alkenes,alkynes and 1,3-enynes.In this study,we report a nickel-catalyzed 1,3-alkylcarbonylation ofσ-bonds in bicyclo[1.1.0]butanes(BCBs)using CO as an economical carbonyl source.展开更多
Strain-release ring-opening trifluoromethylthiolation to construct SCF3-substituted cyclic motifs was under-explored,and di-trifluoromethylthiolation is unachieved.Herein,we present the first trifluoromethylthiolation...Strain-release ring-opening trifluoromethylthiolation to construct SCF3-substituted cyclic motifs was under-explored,and di-trifluoromethylthiolation is unachieved.Herein,we present the first trifluoromethylthiolation of bicyclo[1.1.0]butane(BCB)and bicyclo[2.1.0]pentane.By employing different activators,both mono-and di-trifluoromethylthio substituted cyclobutane and cyclopentane derivatives were successfully obtained.展开更多
Dearomative photocycloaddition of heteroarenes is an efficient method for replacing planar arenes with three-dimensional(3D)scaffolds,such as bicyclo[2.1.1]-hexane(BCH)containing heterocycles.Herein,we report intramol...Dearomative photocycloaddition of heteroarenes is an efficient method for replacing planar arenes with three-dimensional(3D)scaffolds,such as bicyclo[2.1.1]-hexane(BCH)containing heterocycles.Herein,we report intramolecular dearomative[2π+2σ]photocycloadditions of bicyclo[1.1.0]butanes(BCBs)with(benzo)furans and(benzo)thiophenes.These photocycloadditions are initiated through an energy transfer pathway(EnT)or single electron transfer pathway(SET),efficiently yielding unique BCHpyrrolidinone-fused heterocyclic scaffolds.Moreover,the synthetic utility of this photochemical reaction was demonstrated on the basis of large-scale synthesis and diversified transformations.Mechanistic investigations,in conjunction with density functional theory(DFT)calculations,were taken to support the proposed reaction mechanisms.展开更多
Herein,we report the synthesis of multifunctionalized trans-and cis-cyclobutane-basedγ-aminobutyric acid derivatives via diastereodivergent Cu(OTf)_(2)-catalyzed strain-release reactions of bicyclo[1.1.0]butanes with...Herein,we report the synthesis of multifunctionalized trans-and cis-cyclobutane-basedγ-aminobutyric acid derivatives via diastereodivergent Cu(OTf)_(2)-catalyzed strain-release reactions of bicyclo[1.1.0]butanes with amines.This protocol enables precise control of product configuration via ligand selection,providing a powerful tool for modulating the stereochemistry of the resulting compounds.In addition,the synthesized cyclobutane-basedγ-aminobutyric acid derivatives significantly expand substituent diversity,thereby greatly enhancing molecular complexity.The method proceeds under mild conditions and exhibits excellent tolerance toward a broad range of functional groups,making it a versatile platform for the development of novel drug candidates.展开更多
Background and Originality Content Cyclobutane moieties are an important class of motifs since they are frequently found in the medicinally relevant compounds such as alkaloids and pharmaceuticals.[1] Therefore,the de...Background and Originality Content Cyclobutane moieties are an important class of motifs since they are frequently found in the medicinally relevant compounds such as alkaloids and pharmaceuticals.[1] Therefore,the development of efficient synthetic strategies for the construction of cyclobutanes and their derivatives has always been a focus of inter-est.[2a] Photochemical reactions are powerful tools for synthesizing compounds with high complexity and diversity.[2b-h] Among them,photochemical[2+2]cycloaddition is a widely used protocol for the preparation of such compounds.[2h]However,this kind of reaction always suffers from the challenges of controlling the resulting products of the intermolecular[2+2]photodimerization.In principle,to achieve cyclobutanes via[2+2]cycloaddition,the two olefins should be oriented in a parallel fashion keeping the distance less than 4.2 A apart from each other.展开更多
A copper catalyzed stereoselective[2+2]cyclization has been developed,providing a concise protocol to the direct construction of diaryl-substituted cyclobutanes in up to 99%yield with up to>95/5 dr.Meanwhile,the en...A copper catalyzed stereoselective[2+2]cyclization has been developed,providing a concise protocol to the direct construction of diaryl-substituted cyclobutanes in up to 99%yield with up to>95/5 dr.Meanwhile,the enantioselective version of this reaction has also been achieved,leading to a series of optically active diaryl-substituted cyclobutanes with up to 94%ee.展开更多
of main observation and conclusion We herein report the first example of iridium-catalyzed enantioselective C(sp^3)-H borylation of cyclobutanes using benzoxazoline as the directing group.The combination of a chiral b...of main observation and conclusion We herein report the first example of iridium-catalyzed enantioselective C(sp^3)-H borylation of cyclobutanes using benzoxazoline as the directing group.The combination of a chiral bidentate boryl ligand and an iridium precursor has found to effectively catalyze C(sp)-H borylation to afford a variety of cyclobutylboronates with good to excellent enantioselectivities.We also demonstrate the synthetic utility of the current method by converting the stereogenic C—B bond to other functionalities.展开更多
The permeation properties of n-butane, i-butane and n-butane/i-butane mixture （n-butane 24.3% （molar ratio）, i-butane 75.7%） through a tubular silicalite1 zeolite membrane were studied at 298 and 473 K respectivel...The permeation properties of n-butane, i-butane and n-butane/i-butane mixture （n-butane 24.3% （molar ratio）, i-butane 75.7%） through a tubular silicalite1 zeolite membrane were studied at 298 and 473 K respectively. The permselectivities of n-butane and i-butane under pressure difference of 0.06 MPa at 298 and 473 K were 16.3 and 7.4 respectively. The separation factors of n-butane/i-butane mixture were between 2.0 and 2.5 at 298 and 473 K. At 298 K, the permeances of n-butane in the mixture were lower than those of single component while the permeances of i-butane in the mixture were almost the same as those of single component. At 473 K, the permeances of n-butane and i-butane in the mxiture were decreased compared with those of the single component, and the permeance of n-butane decreased more rapidly than that of i-butane.展开更多
A N,N＇-bisferrocenesulfonyl bisbenzimidazole compound 1,4-bis（1-ferrocenesulfonyl-2-benzimidazolyl） butane was prepared. Its crystal structure was determined. The crystal belongs to triclinic with space group P-1 a...A N,N＇-bisferrocenesulfonyl bisbenzimidazole compound 1,4-bis（1-ferrocenesulfonyl-2-benzimidazolyl） butane was prepared. Its crystal structure was determined. The crystal belongs to triclinic with space group P-1 and a= 0.87241（13） nm, b=0.97553（15） nm, c= 1.4120（2） rim, and α= 83.041（2）°, β= 72.454（2）°,γy= 69.732（2）°, the unit cell volume V= 1.0746（3） nm3, the molecule number in one unit cell Z= 1, the absorption coefficient u= 1.191 mm 1, the calculated density Dc= 1.584 g/cm3. The theoretical investigation of the compound as a structure unit was fully optimized by B3LYP/6-31G method in Gaussian 03 package, and the most stable structure of the compound in theory was obtained. The two results were compared. The optimized structure was in accordance with the crystal structure in the main, suggesting that the molecular geometry optimization of the structures was reliable and the calculation method used was reliable. The distribution of atomic charges and the energy, and composition of frontier molecular orbits were analyzed. Thermal analysis indicated that it is stable before melting.展开更多
On September 26,2016 Algerian Space Agency launched AlSat-1B,the second in a series of medium resolution earth observation satellites mission.AlSat-1B electro-thermal propulsion system follows the classic design princ...On September 26,2016 Algerian Space Agency launched AlSat-1B,the second in a series of medium resolution earth observation satellites mission.AlSat-1B electro-thermal propulsion system follows the classic design principle that has been used on previous SSTL-100 missions.With a total dry weight of 5.17 kg,the system is filled with 2.35 L selfpressurized butane.The thruster assembly is designed to use 15 W(at 28 V)redundant heater elements,it is designed to have an average mission thrust of 50 mN.With a warm up time of 10 min,the temperature of the butane will be increased by over 250℃.This is the equivalent of about 35%gain in specific impulse over ambient temperature butane.The spacecraft dry weigh at launch site was 107 kg,the propulsion system is designed to provide at least 19 m/s Delta-v to meet the spacecraft’s mission requirement.To investigate the system readiness for flight,a series of performance tests have been completed at the Surrey Satellite Technology Ltd laboratories(United Kingdom),Satellite Development Centre(Algeria)and Satish Dhawan Space Centre rocket launch site(India),the results of these tests as well as initial flight test results are presented in this paper.展开更多
Six new macrocyclic complexes were synthesized by a template reaction of 1,4-bis（2-formylphenoxy）butane with diamines and Cu（NO3）2·3H2O and their structures were proposed on the basis of elemental analysis, F...Six new macrocyclic complexes were synthesized by a template reaction of 1,4-bis（2-formylphenoxy）butane with diamines and Cu（NO3）2·3H2O and their structures were proposed on the basis of elemental analysis, FT-IR, UV-Vis, magnetic susceptibility measurements, molar conductivity measurements and mass spectra. The metal to ligand molar ratios of the Cu（Ⅱ） complexes were found to be 1 ： 1. The Cu（Ⅱ） complexes are 1 ： 2 electrolytes as shown by their molar conductivities （∧m） in DMF at 10^-3 mol·L^-1. Due to the existence of free ions the Cu（Ⅱ） complexes are electrically conductive. Their configurations were proposed to be probably distorted octahedral.展开更多
基金funding support from the National Key R&D Program of China (Nos.2022YFA1503703,2023YFA1506700)the National Natural Science Foundation of China (Nos.22071118,22271162)the Haihe Laboratory of Sustainable Chemical Transformations and the Fundamental Research Funds for the Central Universities for financial support。
文摘Bicyclo[2.1.1]hexanes(BCHs) are structurally unique C(sp^(3))-rich bicyclic hydrocarbons that are gaining prominence in the field of medicinal chemistry as bioisosteres of benzenoids.The nitrile is an important functionality in drug development due to its ability to improve physicochemical and pharmacokinetic properties and facilitate potential noncovalent interactions with drug targets.Consequently,cyanoarene motifs are commonly found in drug development.The introduction of cyano-BCHs as potential bioisosteres of cyano-arenes shows great promise;however,there are currently no catalytic methods available for their synthesis.Herein,we report a palladium-catalyzed enantioselective [2σ+2π] cycloadditions of bicyclo[1.1.0]butanes with arylidenemalononitriles for the preparation of chiral cyano-BCHs.This method accommodated a wide range of substrates and tolerated various functional groups.The cyano-BCH products could be transformed to molecules with diverse functionality.Control experiments suggest that the reaction proceeds via a zwitterionic intermediate generated by palladium-mediated ring opening of vinyl-carbonyl bicyclo[1.1.0]butanes followed by stereoselective 1,2-addition and intramolecular allylic substitution reactions.
基金Project supported by the National Basic Research Program of China(2004CB2178062005CB221402)+1 种基金the National NaturalScience Foundation of China(20373043)Young Scientists Innovation Foundation of CNPC(04E7025)
文摘The effects of rare earth（RE）on the structure,acidity,and catalytic performance of HZSM-5 zeolite were investigated.A series of RE/HZSM-5 catalysts,containing 7.54% RE（RE=La,Ce,Pr,Nd,Sm,Eu or Gd）,were prepared by the impregnation of the ZSM-5 type zeolites（Si/Al=64：1）with the corresponding RE nitrate aqueous solutions.The catalysts were characterized by means of FT-IR,UV-Vis,NH3-TPD,and IR spectroscopy of adsorbed pyridine.The catalytic performances of the RE/HZSM-5 for the catalytic cracking of mixed butane to light olefins were also measured with a fixed bed microreactor.The results revealed that the addition of light rare earth metal on the HZSM-5 catalyst greatly enhanced the selectivity to olefins,especially to propylene,thus increasing the total yield of olefins in the catalytic cracking of butane.Among the RE-modified HZSM-5 samples,Ce/HZSM-5 gave the highest yield of total olefins,and Nd/HZSM-5 gave the highest yield of propene at a reaction temperature of 600℃.The presence of rare earth metal on the HZSM-5 sample,not only modified the acidic properties of HZSM-5 including the amount of acid sites and acid type,that is,the ratio of L/B（Lewis acid/Brnsted acid）,but also altered the basic properties of it,which in turn promoted the catalytic performance of HZSM-5 for the catalytic cracking of butane.
文摘Te-promoted （1%） vanadium phosphate catalyst （VPDTe） was prepared via VOPO4·2H2O by calcining its precursor VOHPO4·0.5H2O in a flow of n-butane/air.VPDTe catalyst has resulted a higher existence of V5＋ phase with V5＋/V4＋ ratio of 0.23.SEM micrographs show that Te addition altered the arrangement of the platelets from ＂rose-like＂ clusters to layer with irregular shape.Te addition has also markedly lowered the reduction activation energies of the vanadium phosphate catalyst as revealed by TPR profile.The amount of active oxygen species associated with V4＋ phase of the Te promoted catalyst was significantly higher than those of the unpromoted catalyst.These observations suggest that high mobility and availability of reactive oxygen species contributed to the enhancement of n-butane conversion up to 80% at 673 K,while only 47% over unpromoted catalyst （2400 h^-1,1.7% n-butane in air）.
基金Supported by Nanjing University of Posts and Telecommunications (No. NY209032)the National Natural Science Foundation of China (No. 21001065)the Major State Basic Research Development Program of China (973 Program,No. 2009CB930600)
文摘The title coordination polymer 1,{[Cu8（btb）2（CN）8].3H2O}n（btb = 1,4-bis（1,2,4-triazol-1-yl）butane）,has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group C2/c with a = 1.2938（3）,b = 1.9422（5）,c = 0.9406（2） nm,β = 121.891（4）°,V = 2.0066（9） nm3,C24H30Cu8N20O3,Mr = 1155.00,Dc = 1.912 g/cm3,μ（MoKα） = 4.209 mm？1,F（000） = 1140,GOF = 1.184,Z = 2,the final R = 0.0634 and wR = 0.1503 for I 2σ（I）.In complex 1,one-dimensional CuCN zigzag chains are linked by triazolyl groups of btb ligands to form two-dimensional networks,which are further bridged by 1,4-butyl moieties of btb ligands to fabricate a three-dimensional order framework,in which one-dimensional ellipsoid-like channels are observed.
文摘An efficient technology of impregnation of carbonate crushed stone by oil-product based on SCF-impregnation process usage with propane/butane solvent was developed. Regular impregnation throughout the volume of crushed stone sample is achieved. As a result of the appliance of proposed technology, the humidity of the treated crushed stone samples decreased down to 0.54%.
基金Supported by the National Natural Science Foundation of China(No.29776005).
文摘The oxidative dehydrogenation of butane to butadiene and butene was studied using a conventional fixed-bed ractor (FBR), inert membrane reactor (IMR) and mixed inert membrane reactor (MIMR). When IMR and MIMR were employed, a ceramic membrane modified by partially coating with glaze was used to distribute oxygen to a fixed-bed of 24-V-Mg-O catalyst. The oxygen partial pressure in the catalyst bed could be decreased. The effect of feeding modes and operation conditions were investigated. The selectivity of C4 dehydrogenation products (butene and butadiene) was found to be higher in IMR than in FBR. The feeding mode with 20% of air mixing with butane in MIMR was found to be more efficient than the feeding mode with all air permeating through ceramic membrane. The MIMR gave the most smooth temperature profile along the bed.
文摘Eight new macrocyclic complexes were synthesized by template reaction of 1,4-bis（3-aminopropoxy）butane with metal nitrate and 1,3-bis（2-formylphenyl）propane or 1,4-bis（2-formylphenyl）butane and their structures were proposed on the basis of elemental analysis, FTIR, UV-vis, molar conductivity measurements, ^1H NMR and mass spectra. The metals to ligand molar ratios of the complexes were found to be 1： 1. The complexes are 1：2 electrolytes for Pb（II）, Zn（II） and Cd（II） complexes and 1：3 electrolytes for La（III） as shown by their molar conductivities （Am） in DMSO at 10^-3 mol L^-1. Due to the existence of free ions in these complexes, such complexes are electrically conductive. The configurations of La（III） and Pb（II） were proposed to probably octahedral and Zn（II） and Cd（II） complexes were proposed to probably tetrahedral.
文摘The new ligand bis-（1,4-sodium thiolactate） butane （L）-O2CCH3S-（CH2）4SCHCH3CO2- has been prepared from the reaction of disodium salt of thiolactic acid and 1,4-dichlorobutane, while the disodium thiolactate was prepared instanteously through the reaction of thiolactic acid with NaOH. Mono and dinuclear complexes were obtained by direct reaction of the above ligands with H[AuCI4] in 1 ： 1, 2：1, 1：2, 2：2 and 3：1 ligands to metal molar ratio. The prepared complexes were characterized by elemental analysis, spectral studies FTIR （Fourier transform Infrared） and UV-Vis, magnetic measurement, conductivity measurement and IHNMR for the ligand （L） and some of the complexes. The conductance data indicate that the complexes of the formulas Na[Au（SCH3CHCOO）2], Na[Au（SCH3CHCOO）（OOCCHCH3SH）2] and [Au（L）]Cl are 1：1 electrolyte. Electronic spectra and magnetic moment values indicate the presence of square planner geometry around Au（III） ions.
基金supported by the National Natural Science Foundation of China(22471068)。
文摘As the smallest fused hydrocarbon and one of the most strained carbocycles,bicyclo[1.1.0]butane(BCB)undergoes a wide array of strain-releasing transformations,thereby exhibiting a rich and varied chemical profile.Although BCBs have been synthesized and studied for over 60 years,its potential as a versatile building block for expanding chemical space has remained largely underexplored.Recently,the emergence of diverse activation strategies,such as photocatalysis,boryl radical catalysis,Lewis/Bronsted acid catalysis,palladium catalysis,Lewis base catalysis,and radical relay strategies,has revolutionized BCB chemistry into a powerful toolbox for expanding the chemical space of scaffold-diverse molecules,with a particular focus on cyclobutane,cyclobutene,and bicyclo[n.1.1]alkane scaffolds.In this review,we highlight the latest advancements in the divergent transformations of BCBs to construct cyclobutyl-decorated architectures from common precursors,with a particular emphasis on elucidating the reaction mechanisms.The content is organized based on key regulatory factors for product divergent formation.It is anticipated that this review will stimulate increased interest among researchers in integrating the concept of controllable divergent synthesis into BCB chemistry.By doing so,it is expected to further unlock the potential of BCBs in expanding molecular space and to extend the reach of BCB chemistry into a wider array of synthetic applications.
基金support from the National Natural Science Foundation of China(No.22171220)the XJTU Research Fund for Al Science is greatly appreciated.
文摘Transition-metal-catalyzed radical-mediated four-component carbonylation reactions offer a sustainable and efficient strategy for modular synthesis of complex carbonyl compounds from simple feedstocks.However,current studies have primarily focused on the alkylcarbonylation ofπ-bonds in unsaturated hydrocarbons,including alkenes,alkynes and 1,3-enynes.In this study,we report a nickel-catalyzed 1,3-alkylcarbonylation ofσ-bonds in bicyclo[1.1.0]butanes(BCBs)using CO as an economical carbonyl source.
基金supported by the National Key Research and Development Program of China(2021YFF0701700)the NFSC(21925105 and 92156001)+1 种基金the Natural Science Foundation of Tianjin(grant no.24JCZDJC00700)the Haihe Laboratory of Sustainable Chemical Transformations,and the Fundamental Research Funds for the Central Universities.
文摘Strain-release ring-opening trifluoromethylthiolation to construct SCF3-substituted cyclic motifs was under-explored,and di-trifluoromethylthiolation is unachieved.Herein,we present the first trifluoromethylthiolation of bicyclo[1.1.0]butane(BCB)and bicyclo[2.1.0]pentane.By employing different activators,both mono-and di-trifluoromethylthio substituted cyclobutane and cyclopentane derivatives were successfully obtained.
基金supported by the National Key R&D Program of China(2022YFC2303100)the National Natural Science Foundation of China(22305261,21372250,21121062,21302203,20732008,21772037,21772226,21861132014,91956115,22171078)+1 种基金the Shanghai Municipal Science and Technology Major Project(2018SHZDZX03)the Fundamental Research Funds for the Central Universities(222201717003)。
文摘Dearomative photocycloaddition of heteroarenes is an efficient method for replacing planar arenes with three-dimensional(3D)scaffolds,such as bicyclo[2.1.1]-hexane(BCH)containing heterocycles.Herein,we report intramolecular dearomative[2π+2σ]photocycloadditions of bicyclo[1.1.0]butanes(BCBs)with(benzo)furans and(benzo)thiophenes.These photocycloadditions are initiated through an energy transfer pathway(EnT)or single electron transfer pathway(SET),efficiently yielding unique BCHpyrrolidinone-fused heterocyclic scaffolds.Moreover,the synthetic utility of this photochemical reaction was demonstrated on the basis of large-scale synthesis and diversified transformations.Mechanistic investigations,in conjunction with density functional theory(DFT)calculations,were taken to support the proposed reaction mechanisms.
基金financial support from the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2022R01007)the Start-up Research Grant from Zhejiang Normal University.
文摘Herein,we report the synthesis of multifunctionalized trans-and cis-cyclobutane-basedγ-aminobutyric acid derivatives via diastereodivergent Cu(OTf)_(2)-catalyzed strain-release reactions of bicyclo[1.1.0]butanes with amines.This protocol enables precise control of product configuration via ligand selection,providing a powerful tool for modulating the stereochemistry of the resulting compounds.In addition,the synthesized cyclobutane-basedγ-aminobutyric acid derivatives significantly expand substituent diversity,thereby greatly enhancing molecular complexity.The method proceeds under mild conditions and exhibits excellent tolerance toward a broad range of functional groups,making it a versatile platform for the development of novel drug candidates.
文摘Background and Originality Content Cyclobutane moieties are an important class of motifs since they are frequently found in the medicinally relevant compounds such as alkaloids and pharmaceuticals.[1] Therefore,the development of efficient synthetic strategies for the construction of cyclobutanes and their derivatives has always been a focus of inter-est.[2a] Photochemical reactions are powerful tools for synthesizing compounds with high complexity and diversity.[2b-h] Among them,photochemical[2+2]cycloaddition is a widely used protocol for the preparation of such compounds.[2h]However,this kind of reaction always suffers from the challenges of controlling the resulting products of the intermolecular[2+2]photodimerization.In principle,to achieve cyclobutanes via[2+2]cycloaddition,the two olefins should be oriented in a parallel fashion keeping the distance less than 4.2 A apart from each other.
基金We thank the NSFC(Nos.21432011,21772224)the CAS(Nos.QYZDY-SSW-SLH016,XDB20000000,2017301)the STCSM(Nos.17JC1401200,17ZR1436900)for the financial support.We also thank Dr.Xue-Bing Leng(SIOC)for X-ray crystal analysis.
文摘A copper catalyzed stereoselective[2+2]cyclization has been developed,providing a concise protocol to the direct construction of diaryl-substituted cyclobutanes in up to 99%yield with up to>95/5 dr.Meanwhile,the enantioselective version of this reaction has also been achieved,leading to a series of optically active diaryl-substituted cyclobutanes with up to 94%ee.
基金We thank the National Natural Science Foundation of China(21573262,21776260,21873261,and 91956116)the Natural Science Foundation of Jiangsu Province(BK20170422)for thegenerous support.
文摘of main observation and conclusion We herein report the first example of iridium-catalyzed enantioselective C(sp^3)-H borylation of cyclobutanes using benzoxazoline as the directing group.The combination of a chiral bidentate boryl ligand and an iridium precursor has found to effectively catalyze C(sp)-H borylation to afford a variety of cyclobutylboronates with good to excellent enantioselectivities.We also demonstrate the synthetic utility of the current method by converting the stereogenic C—B bond to other functionalities.
文摘The permeation properties of n-butane, i-butane and n-butane/i-butane mixture （n-butane 24.3% （molar ratio）, i-butane 75.7%） through a tubular silicalite1 zeolite membrane were studied at 298 and 473 K respectively. The permselectivities of n-butane and i-butane under pressure difference of 0.06 MPa at 298 and 473 K were 16.3 and 7.4 respectively. The separation factors of n-butane/i-butane mixture were between 2.0 and 2.5 at 298 and 473 K. At 298 K, the permeances of n-butane in the mixture were lower than those of single component while the permeances of i-butane in the mixture were almost the same as those of single component. At 473 K, the permeances of n-butane and i-butane in the mxiture were decreased compared with those of the single component, and the permeance of n-butane decreased more rapidly than that of i-butane.
基金Project supported by the Natural Science Foundation of Shaanxi Province （No. 2010JM2019）, the Postdoctoral Science Foundation of Northwest University （No. BK08008）, the National Science Fund for Fostering Talents in Basic Science （No. J0830417）, and the State Key Program of National Natural Science of China （No. 20931005）.
文摘A N,N＇-bisferrocenesulfonyl bisbenzimidazole compound 1,4-bis（1-ferrocenesulfonyl-2-benzimidazolyl） butane was prepared. Its crystal structure was determined. The crystal belongs to triclinic with space group P-1 and a= 0.87241（13） nm, b=0.97553（15） nm, c= 1.4120（2） rim, and α= 83.041（2）°, β= 72.454（2）°,γy= 69.732（2）°, the unit cell volume V= 1.0746（3） nm3, the molecule number in one unit cell Z= 1, the absorption coefficient u= 1.191 mm 1, the calculated density Dc= 1.584 g/cm3. The theoretical investigation of the compound as a structure unit was fully optimized by B3LYP/6-31G method in Gaussian 03 package, and the most stable structure of the compound in theory was obtained. The two results were compared. The optimized structure was in accordance with the crystal structure in the main, suggesting that the molecular geometry optimization of the structures was reliable and the calculation method used was reliable. The distribution of atomic charges and the energy, and composition of frontier molecular orbits were analyzed. Thermal analysis indicated that it is stable before melting.
文摘On September 26,2016 Algerian Space Agency launched AlSat-1B,the second in a series of medium resolution earth observation satellites mission.AlSat-1B electro-thermal propulsion system follows the classic design principle that has been used on previous SSTL-100 missions.With a total dry weight of 5.17 kg,the system is filled with 2.35 L selfpressurized butane.The thruster assembly is designed to use 15 W(at 28 V)redundant heater elements,it is designed to have an average mission thrust of 50 mN.With a warm up time of 10 min,the temperature of the butane will be increased by over 250℃.This is the equivalent of about 35%gain in specific impulse over ambient temperature butane.The spacecraft dry weigh at launch site was 107 kg,the propulsion system is designed to provide at least 19 m/s Delta-v to meet the spacecraft’s mission requirement.To investigate the system readiness for flight,a series of performance tests have been completed at the Surrey Satellite Technology Ltd laboratories(United Kingdom),Satellite Development Centre(Algeria)and Satish Dhawan Space Centre rocket launch site(India),the results of these tests as well as initial flight test results are presented in this paper.
文摘Six new macrocyclic complexes were synthesized by a template reaction of 1,4-bis（2-formylphenoxy）butane with diamines and Cu（NO3）2·3H2O and their structures were proposed on the basis of elemental analysis, FT-IR, UV-Vis, magnetic susceptibility measurements, molar conductivity measurements and mass spectra. The metal to ligand molar ratios of the Cu（Ⅱ） complexes were found to be 1 ： 1. The Cu（Ⅱ） complexes are 1 ： 2 electrolytes as shown by their molar conductivities （∧m） in DMF at 10^-3 mol·L^-1. Due to the existence of free ions the Cu（Ⅱ） complexes are electrically conductive. Their configurations were proposed to be probably distorted octahedral.
