Citric acid is an important organic substance whose marketing concerns various fields. Nevertheless, until 1997 the scientific literature reported little information about the process of crystallization by cooling thr...Citric acid is an important organic substance whose marketing concerns various fields. Nevertheless, until 1997 the scientific literature reported little information about the process of crystallization by cooling through which the commercial product is obtained. In particular, the available studies were aimed to investigate only the kinetics of nucleation and crystal growth neglecting some effective aspects of the industrial crystallization in mechanically stirred apparatus. In order to fill that sci-tech gap, the Department of Chemical Engineering at the University ＂La Sapienza＂ of Rome decided to lead a long and meticulous experimental research on the crystallization in discontinuous （batch） of CAM （citric acid monohydrate） in the allotropic form that is stable at room temperature. Due to the number of people involved in that pioneering work, carried out in the historic laboratories of＂La Sapienza＂ （Faculty of Engineering）, and motivated by the publication of related M.Sc. dissertations and research papers, such collective effort was called ＂School of Industrial Crystallization＂. Among the graduate students in Chemical Engineering that 17 years ago participated in that fruitful experience there was also the author who, under the supervision of Prof. Barbara Mazzarotta, had the specific task of assessing the effects on CAM of changing the crystallization operating conditions until their optimization; the achievements are briefly illustrated in this paper.展开更多
We herein report two crystals based on 2-（imidazo[1,2-a]pyridin-2-yl）-2-oxoacetic acid rad- ical and its perchlorate, and investigate the relationship between magnetic properties and crystal stacking structures or s...We herein report two crystals based on 2-（imidazo[1,2-a]pyridin-2-yl）-2-oxoacetic acid rad- ical and its perchlorate, and investigate the relationship between magnetic properties and crystal stacking structures or supramolecular interactions. 2-（imidazo[1,2-a]pyridin-2-yl）- 2-oxoaeetic acid radical in two crystals mainly exist as diamagnetic dimer formed via short atomic contacts or supramolecular interactions （hydrogen bonds, anion-Tr or lone- pair-~r interactions）, leading to low magnetic susceptibilities. 2-（imidazo[1,2-a]pyridin-2-yl）- 2-oxoaeetic acid radical crystal exhibits quasi-one-dimensional columnar stacking chain and weak antiferromagnetism. However, its perchlorate crystal possesses one-dimensional double- stranded chain structure assembled through double hydrogen bonds and anion-To interactions, and reveals weak ferromagnetism.展开更多
The title compound (C30H32NO4PGe), O,O-dimethyl-N-(β-triphenylgermanyl) propionyl-α-aminobenzylphosphonates was synthesized by a convenient method, and its crystal structure was determined by single-crystal X-ray di...The title compound (C30H32NO4PGe), O,O-dimethyl-N-(β-triphenylgermanyl) propionyl-α-aminobenzylphosphonates was synthesized by a convenient method, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal is triclinic, space group P-1 with parameters: a=9.7753(5), b=11.5773(5), c=13.5059(6) ?, α=104.185(1),β= 95.971(1), γ =96.727(1)°, V=1457.63(12) ?3, Z=2, Mr=574.13, Dc=1.308 g/cm3, λ=0.71073 ?, μ = 1.139mm-1, and F(000)=596. The structure was solved by direct methods. The structure was refined to R=0.0257, wR=0.0705 for 5080 observed reflections with I >2σ(I).The result of structure analysis indicates that atom Ge is sp3 hydridized because the arrangement of the four carbon atoms bonded to it is a distorted tetrahedron. The geometry of the three phenyl groups linking with the Ge atom looks like a propeller form.展开更多
Molybdenum(I) -compound [Mo2(SC6H11)2(CO)8]1,crystallizes in monoclinic,space group P21/c with a=9.5863(9),b=9.4469(9),c=13.869(1)A,β=99.697(2)°,V=1238.1(2)A^3,Z=2,Dc=1.734g/cm^3 ,μ=12.23cm^-1 and F(000)=644.Th...Molybdenum(I) -compound [Mo2(SC6H11)2(CO)8]1,crystallizes in monoclinic,space group P21/c with a=9.5863(9),b=9.4469(9),c=13.869(1)A,β=99.697(2)°,V=1238.1(2)A^3,Z=2,Dc=1.734g/cm^3 ,μ=12.23cm^-1 and F(000)=644.The final R=0.0455 and wR=0.1159 for 1590 observed reflections with I>2ó(I).1 possesses a rhombic bimetallic core MoS2Mo with the Mo-Mo bond length of 2.975(1) and Mo-S of 2.485(2)A。展开更多
The reaction of bis(dibromophenylstannyl)methane with 1, 3-bis(3, 5-dimethyl- pyrazol-1-yl)propane in a 1:1 or 1:2 ratio yields only 1:1 adduct which partly hydrolyzes to the title complex (C26H38Br6N4O2Sn2, Mr = 1155...The reaction of bis(dibromophenylstannyl)methane with 1, 3-bis(3, 5-dimethyl- pyrazol-1-yl)propane in a 1:1 or 1:2 ratio yields only 1:1 adduct which partly hydrolyzes to the title complex (C26H38Br6N4O2Sn2, Mr = 1155.42) during crystal growing. The title complex is of triclinic, space group P with a = 10.886(1), b = 12.508(1), c = 13.879(1) ? = 85.762(2), = 85.159(2), = 84.020(2)? V = 1868.8(4) ?, Z = 2, Dc = 2.046 g/cm3, (MoK) = 0.71073 ? = 7.778 mm-1, F(000) = 1088, R = 0.0488 and wR = 0.1157 for 7560 observed reflections with I ≥ 2(I). The crystal structure analysis indicates that there is no direct interaction between the ligand and bis(dibromophenylstannyl)methane, and two tin atoms are bridged by two bromide atoms from the partial hydrolysis of this adduct.展开更多
The Diels-Alder reaction of bis(diphenylphosphine oxide)butadiyne (BDPPOB) with spiro[2.4]hepta-4,6-diene affords the title compound, 2-(diphenylphosphine oxide)-3-(diphen- ylphosphine oxide ethynyl)spiro[bicyclo[2.2....The Diels-Alder reaction of bis(diphenylphosphine oxide)butadiyne (BDPPOB) with spiro[2.4]hepta-4,6-diene affords the title compound, 2-(diphenylphosphine oxide)-3-(diphen- ylphosphine oxide ethynyl)spiro[bicyclo[2.2.1] hepta-2,5-diene-7,1-cyclopropane] (DDSHC, C35H28O2P2, Mr = 542). Its crystal structure belongs to monoclinic system, space group P21/n with a =12.708(3), b = 14.666(4), c = 15.048(4) ? = 93.903(5) ? V = 2798.1(13) ?, Z = 4, Dc = 1.288g/cm3, F(000)=1136, (MoK? = 0.187mm-1, final R = 0.0626 and wR= 0.1422 for 4685 independent reflections with I > 2(I). Structural analyses reveal that the title compound is nonplanar and the dihedral angles between two phenyl rings around each phosphorus atom are 71.7(2) and 70.7(3)? respectively.展开更多
The influence of solvent (in its gaseous state) on the stability of crystallized organic compounds was investigated. Through two examples of studies on the solid/vapour equilibria made in our lab, several behaviors we...The influence of solvent (in its gaseous state) on the stability of crystallized organic compounds was investigated. Through two examples of studies on the solid/vapour equilibria made in our lab, several behaviors were highlighted: (i) a new hydrated phase (thermodynamically stable) of an active pharmaceutical ingredient (API) was detected after the recrystallization starting from a deliquescent state, (ii) a spontaneous resolution of a hydrated racemic compound towards an anhydrous conglomerate can occur during the desolvation under the precise conditions of temperature and humidity. This study illustrates that knowledge about solid/vapour equilibrium is a crucial step during the complete characterization of solid organic compounds.展开更多
A novel ionic organotin complex{[Ph_(2)Sn]_(2)[2,6-(O_(2)C)_(2)]C_(5)H_(3)N}_(3)H_(2)O}^(2-)[HNEt_(3)]^(2+)has been unexpectedly obtained by the reaction of Ph_(3)SnCl and 2,6-pyridine dicarboxylic acid in 1:1 molar r...A novel ionic organotin complex{[Ph_(2)Sn]_(2)[2,6-(O_(2)C)_(2)]C_(5)H_(3)N}_(3)H_(2)O}^(2-)[HNEt_(3)]^(2+)has been unexpectedly obtained by the reaction of Ph_(3)SnCl and 2,6-pyridine dicarboxylic acid in 1:1 molar ratio in the presence of organic base Et_(3)N.Possible dephenylation mechanism was illustrated.The X-ray diffraction study has shown that the title complex consists of cation moiety[HNEt_(3)]^(+)and anion moiety{[Ph_(2)Sn]_(2)[2,6-(O_(2)C_(2))C_(5)H_(3)N]_(3)H_(2)O}^(2-)with tin(IV)in a pengonal bipyramidal coordination geometry.展开更多
This paper reports a new donor-acceptor copolymer semiconductor, PTBTh, comprising bithiophene and bithiazole where the regular coplanar structure and the intramolecular charge transfer are expected to increase the op...This paper reports a new donor-acceptor copolymer semiconductor, PTBTh, comprising bithiophene and bithiazole where the regular coplanar structure and the intramolecular charge transfer are expected to increase the opportunity for --- stacking and charge transport. The AFM image shows lamellar stacking of the polymer on the surface. The field-effect transistor (FET) properties of PTBTh have been evaluated by a bottom-contact/bottom-gate TFT configuration. The device showed a high hole mobility of 1.14×10-2 cm2 V-1 s-1 and a current on/off ratio of 3×105 with the polymer thin film annealed at a mild temperature of 120 ℃ when measured under ambient conditions.展开更多
文摘Citric acid is an important organic substance whose marketing concerns various fields. Nevertheless, until 1997 the scientific literature reported little information about the process of crystallization by cooling through which the commercial product is obtained. In particular, the available studies were aimed to investigate only the kinetics of nucleation and crystal growth neglecting some effective aspects of the industrial crystallization in mechanically stirred apparatus. In order to fill that sci-tech gap, the Department of Chemical Engineering at the University ＂La Sapienza＂ of Rome decided to lead a long and meticulous experimental research on the crystallization in discontinuous （batch） of CAM （citric acid monohydrate） in the allotropic form that is stable at room temperature. Due to the number of people involved in that pioneering work, carried out in the historic laboratories of＂La Sapienza＂ （Faculty of Engineering）, and motivated by the publication of related M.Sc. dissertations and research papers, such collective effort was called ＂School of Industrial Crystallization＂. Among the graduate students in Chemical Engineering that 17 years ago participated in that fruitful experience there was also the author who, under the supervision of Prof. Barbara Mazzarotta, had the specific task of assessing the effects on CAM of changing the crystallization operating conditions until their optimization; the achievements are briefly illustrated in this paper.
基金This work was supported by the National Natural Science Foundation of China （No.21172210）.
文摘We herein report two crystals based on 2-（imidazo[1,2-a]pyridin-2-yl）-2-oxoacetic acid rad- ical and its perchlorate, and investigate the relationship between magnetic properties and crystal stacking structures or supramolecular interactions. 2-（imidazo[1,2-a]pyridin-2-yl）- 2-oxoaeetic acid radical in two crystals mainly exist as diamagnetic dimer formed via short atomic contacts or supramolecular interactions （hydrogen bonds, anion-Tr or lone- pair-~r interactions）, leading to low magnetic susceptibilities. 2-（imidazo[1,2-a]pyridin-2-yl）- 2-oxoaeetic acid radical crystal exhibits quasi-one-dimensional columnar stacking chain and weak antiferromagnetism. However, its perchlorate crystal possesses one-dimensional double- stranded chain structure assembled through double hydrogen bonds and anion-To interactions, and reveals weak ferromagnetism.
文摘The title compound (C30H32NO4PGe), O,O-dimethyl-N-(β-triphenylgermanyl) propionyl-α-aminobenzylphosphonates was synthesized by a convenient method, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal is triclinic, space group P-1 with parameters: a=9.7753(5), b=11.5773(5), c=13.5059(6) ?, α=104.185(1),β= 95.971(1), γ =96.727(1)°, V=1457.63(12) ?3, Z=2, Mr=574.13, Dc=1.308 g/cm3, λ=0.71073 ?, μ = 1.139mm-1, and F(000)=596. The structure was solved by direct methods. The structure was refined to R=0.0257, wR=0.0705 for 5080 observed reflections with I >2σ(I).The result of structure analysis indicates that atom Ge is sp3 hydridized because the arrangement of the four carbon atoms bonded to it is a distorted tetrahedron. The geometry of the three phenyl groups linking with the Ge atom looks like a propeller form.
基金This research was supported by grants from the NNSFC SKLSC(No.01008 and No.980148-2)
文摘Molybdenum(I) -compound [Mo2(SC6H11)2(CO)8]1,crystallizes in monoclinic,space group P21/c with a=9.5863(9),b=9.4469(9),c=13.869(1)A,β=99.697(2)°,V=1238.1(2)A^3,Z=2,Dc=1.734g/cm^3 ,μ=12.23cm^-1 and F(000)=644.The final R=0.0455 and wR=0.1159 for 1590 observed reflections with I>2ó(I).1 possesses a rhombic bimetallic core MoS2Mo with the Mo-Mo bond length of 2.975(1) and Mo-S of 2.485(2)A。
基金Supported by National Natural Science Foundation of China (No. 29902002) the Research Fund for the Doctoral Program of Higher Education
文摘The reaction of bis(dibromophenylstannyl)methane with 1, 3-bis(3, 5-dimethyl- pyrazol-1-yl)propane in a 1:1 or 1:2 ratio yields only 1:1 adduct which partly hydrolyzes to the title complex (C26H38Br6N4O2Sn2, Mr = 1155.42) during crystal growing. The title complex is of triclinic, space group P with a = 10.886(1), b = 12.508(1), c = 13.879(1) ? = 85.762(2), = 85.159(2), = 84.020(2)? V = 1868.8(4) ?, Z = 2, Dc = 2.046 g/cm3, (MoK) = 0.71073 ? = 7.778 mm-1, F(000) = 1088, R = 0.0488 and wR = 0.1157 for 7560 observed reflections with I ≥ 2(I). The crystal structure analysis indicates that there is no direct interaction between the ligand and bis(dibromophenylstannyl)methane, and two tin atoms are bridged by two bromide atoms from the partial hydrolysis of this adduct.
基金This work was supported by the NNSFC (No. 29832030 and 20072018)
文摘The Diels-Alder reaction of bis(diphenylphosphine oxide)butadiyne (BDPPOB) with spiro[2.4]hepta-4,6-diene affords the title compound, 2-(diphenylphosphine oxide)-3-(diphen- ylphosphine oxide ethynyl)spiro[bicyclo[2.2.1] hepta-2,5-diene-7,1-cyclopropane] (DDSHC, C35H28O2P2, Mr = 542). Its crystal structure belongs to monoclinic system, space group P21/n with a =12.708(3), b = 14.666(4), c = 15.048(4) ? = 93.903(5) ? V = 2798.1(13) ?, Z = 4, Dc = 1.288g/cm3, F(000)=1136, (MoK? = 0.187mm-1, final R = 0.0626 and wR= 0.1422 for 4685 independent reflections with I > 2(I). Structural analyses reveal that the title compound is nonplanar and the dihedral angles between two phenyl rings around each phosphorus atom are 71.7(2) and 70.7(3)? respectively.
文摘The influence of solvent (in its gaseous state) on the stability of crystallized organic compounds was investigated. Through two examples of studies on the solid/vapour equilibria made in our lab, several behaviors were highlighted: (i) a new hydrated phase (thermodynamically stable) of an active pharmaceutical ingredient (API) was detected after the recrystallization starting from a deliquescent state, (ii) a spontaneous resolution of a hydrated racemic compound towards an anhydrous conglomerate can occur during the desolvation under the precise conditions of temperature and humidity. This study illustrates that knowledge about solid/vapour equilibrium is a crucial step during the complete characterization of solid organic compounds.
文摘A novel ionic organotin complex{[Ph_(2)Sn]_(2)[2,6-(O_(2)C)_(2)]C_(5)H_(3)N}_(3)H_(2)O}^(2-)[HNEt_(3)]^(2+)has been unexpectedly obtained by the reaction of Ph_(3)SnCl and 2,6-pyridine dicarboxylic acid in 1:1 molar ratio in the presence of organic base Et_(3)N.Possible dephenylation mechanism was illustrated.The X-ray diffraction study has shown that the title complex consists of cation moiety[HNEt_(3)]^(+)and anion moiety{[Ph_(2)Sn]_(2)[2,6-(O_(2)C_(2))C_(5)H_(3)N]_(3)H_(2)O}^(2-)with tin(IV)in a pengonal bipyramidal coordination geometry.
基金supported by the National Natural Science Foundation of China (20772094)
文摘This paper reports a new donor-acceptor copolymer semiconductor, PTBTh, comprising bithiophene and bithiazole where the regular coplanar structure and the intramolecular charge transfer are expected to increase the opportunity for --- stacking and charge transport. The AFM image shows lamellar stacking of the polymer on the surface. The field-effect transistor (FET) properties of PTBTh have been evaluated by a bottom-contact/bottom-gate TFT configuration. The device showed a high hole mobility of 1.14×10-2 cm2 V-1 s-1 and a current on/off ratio of 3×105 with the polymer thin film annealed at a mild temperature of 120 ℃ when measured under ambient conditions.
