Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam pl...Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam ple has a6 H modification.The difference between the integrated intensities m easured byω scan in the triple- axis diffraction set- up finds some convincing evidence that the surface is either a Si- terminated face or C- terminated face.The experi- mental ratios of| F( 0 0 0 L) | 2 / | F( 0 0 0 L) | 2 are in good agreem entwith the calculated ones after the dispersion cor- rections to the atomic scattering factors( L=6 ,12 and18,respectively) .Thus,this m easurem ent technique is con- venient for the application of the materials with remarkable surface polarity.展开更多
X-ray diffraction （XRD） was used to study the structure of the organic crystallite unit （La, Lo doo2） in coals collected from Henan and Shanxi Provinces. XRD patterns of coal were collected in a step-scan mode （0...X-ray diffraction （XRD） was used to study the structure of the organic crystallite unit （La, Lo doo2） in coals collected from Henan and Shanxi Provinces. XRD patterns of coal were collected in a step-scan mode （0.1 °/step） over an angular range of 2-90° （20）, allowing 8 s at each step. The structure of the crystallite unit was determined from the Scherrer equation and peak parameters deduced from whole pattern fitting. The results show that the structure of the crystallite unit in coal is mainly controlled by the coal rank. As the coal rank increases the average diameter of a coal crystallite unit （La） increases, the interlayer spacing （doo2） decreases slightly, and the average height of a coal crystallite unit （Lc） increases at first but then decreases. A new diffraction peak from the crystallite unit in coal was found at a low scattering angle in the XRD pattern （2-10~）. This suggests a structure with an inter-layer spacing from 1.9 to 2.8 nm exists in coal crystallites.展开更多
New heteroleptic and homoleptic complexes of the type[Pd（4,5-dmbipy）C12], [Pd（4,5-dmbipy）L2], and [Pd（4,5-dimebipy）2]2＋ （L = Pyridine or 4-methylpyridine（4-picoline）, bipy = 2,2＇-bipyridine, and 4,5-dimebip...New heteroleptic and homoleptic complexes of the type[Pd（4,5-dmbipy）C12], [Pd（4,5-dmbipy）L2], and [Pd（4,5-dimebipy）2]2＋ （L = Pyridine or 4-methylpyridine（4-picoline）, bipy = 2,2＇-bipyridine, and 4,5-dimebipy = 4,5-dimethyl-2,2＇-bipyridine） were synthesized and characterized by IH NMR and elemental analysis. The crystal structure of bis（4-methylpyridine）-4,5- dimethyl-2,2＇-bipyridinepalladium（II）perchlorate [Pd（4,5-dmbipy）（4-pic）2]（CIO4）2 was also determined by single crystal X-ray diffraction. This complex crystallized in the triclinic crystal system and space group PI with a = 9.562 （2）, b = 11.326 （4）, c = 15.0120 （10） A°; α = 70.940°, β= 77.60 （2）, γ= 67.86 （2） and z = 4. The Pd （II） in square planar environment showed a small distortion towards tetrahedral through one coordinated bipyridine ring twisting with respect to the other.展开更多
Two new different Cu(Ⅱ) MOFs with the same 1,3,5-tris(1-imidazolyl) benzene(tib) ligand {[Cu(tib)2]·(H2O)2·Br2}n(1) and {[Cu2(tib)·Br·Cl]·2Br}n(2) were obtained by one pot synthesized of tib ...Two new different Cu(Ⅱ) MOFs with the same 1,3,5-tris(1-imidazolyl) benzene(tib) ligand {[Cu(tib)2]·(H2O)2·Br2}n(1) and {[Cu2(tib)·Br·Cl]·2Br}n(2) were obtained by one pot synthesized of tib with CuBr in the presences of HCl and water. X-ray single crystal diffraction analyses indicate that both complexes 1 and 2 have two dimensional frameworks containing different building blocks. Each Cu(Ⅱ) atom in complex 1 is coordinated by four N atoms from different tib ligands. However, there are two different cryptographic Cu(Ⅱ) atoms in complex 2, one is four coordinated by two bromine atoms and two N atoms from different tib ligands, the other is six coordinated by two chloride atoms and four N atoms from different tib ligands. The thermal gravimetric analysis of complexes 1 and 2 are depicted in the paper.展开更多
Employing unsymmetrical 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,2′-bipyridine as mixed ligands, a new low-dimensional coordination polymer [Zn(MMTA) 2 (2,2′-bipy)] n (MMTA = 2-mercapto-5-methyl-1,3,4-thiadiazole...Employing unsymmetrical 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,2′-bipyridine as mixed ligands, a new low-dimensional coordination polymer [Zn(MMTA) 2 (2,2′-bipy)] n (MMTA = 2-mercapto-5-methyl-1,3,4-thiadiazole, 2,2′-bipy = 2,2′-bipyridine), has been synthesized under solvothermal condition and characterized by single crystal X-ray diffraction. This compound crys- tallizes in the noncentrosymmetric space group Cc, with cell parameters: a = 8.291(4) , b = 15.483(9) , c = 15.620(6) , = 96.00(5)°, V = 1994.1(2) 3 , and Z = 4. The mixed ligands link the zinc center into a mononuclear unit, which is futher linked by weak C-H···N and C-H···S hydrogen bonds into a three-dimensional noncentrosymmetric framework. The compound exhibits intense photoluminescence and distinct NLO properties at room temperature. The intensity of the green light produced by the powder sample of the compound is about 3.2 times that produced by KDP powder. On the basis of the results of TG analysis, the structure is thermally stable up to ～260 °C.展开更多
文摘Structure and polarity of the Si C single crystal have been analyzed with the four- circle X- ray diffraction method by a double- crystal diffractom eter.The hexagonal{ 10 15 } pole figure shows that this Si C sam ple has a6 H modification.The difference between the integrated intensities m easured byω scan in the triple- axis diffraction set- up finds some convincing evidence that the surface is either a Si- terminated face or C- terminated face.The experi- mental ratios of| F( 0 0 0 L) | 2 / | F( 0 0 0 L) | 2 are in good agreem entwith the calculated ones after the dispersion cor- rections to the atomic scattering factors( L=6 ,12 and18,respectively) .Thus,this m easurem ent technique is con- venient for the application of the materials with remarkable surface polarity.
基金supported in part by Program for New Century Excellent Talents in University of China (No. NCET-10-0133)Innovation Scientists and Technicians Troop Construction Projects of Henan Province (No. 114100510004)
文摘X-ray diffraction （XRD） was used to study the structure of the organic crystallite unit （La, Lo doo2） in coals collected from Henan and Shanxi Provinces. XRD patterns of coal were collected in a step-scan mode （0.1 °/step） over an angular range of 2-90° （20）, allowing 8 s at each step. The structure of the crystallite unit was determined from the Scherrer equation and peak parameters deduced from whole pattern fitting. The results show that the structure of the crystallite unit in coal is mainly controlled by the coal rank. As the coal rank increases the average diameter of a coal crystallite unit （La） increases, the interlayer spacing （doo2） decreases slightly, and the average height of a coal crystallite unit （Lc） increases at first but then decreases. A new diffraction peak from the crystallite unit in coal was found at a low scattering angle in the XRD pattern （2-10~）. This suggests a structure with an inter-layer spacing from 1.9 to 2.8 nm exists in coal crystallites.
文摘New heteroleptic and homoleptic complexes of the type[Pd（4,5-dmbipy）C12], [Pd（4,5-dmbipy）L2], and [Pd（4,5-dimebipy）2]2＋ （L = Pyridine or 4-methylpyridine（4-picoline）, bipy = 2,2＇-bipyridine, and 4,5-dimebipy = 4,5-dimethyl-2,2＇-bipyridine） were synthesized and characterized by IH NMR and elemental analysis. The crystal structure of bis（4-methylpyridine）-4,5- dimethyl-2,2＇-bipyridinepalladium（II）perchlorate [Pd（4,5-dmbipy）（4-pic）2]（CIO4）2 was also determined by single crystal X-ray diffraction. This complex crystallized in the triclinic crystal system and space group PI with a = 9.562 （2）, b = 11.326 （4）, c = 15.0120 （10） A°; α = 70.940°, β= 77.60 （2）, γ= 67.86 （2） and z = 4. The Pd （II） in square planar environment showed a small distortion towards tetrahedral through one coordinated bipyridine ring twisting with respect to the other.
基金funded by the National Natural Science Foundation of China(21261009)Young Scientist Foundation of Jiangxi Provincethe Education Fund of Jiangxi Province(GJJ13434)
文摘Two new different Cu(Ⅱ) MOFs with the same 1,3,5-tris(1-imidazolyl) benzene(tib) ligand {[Cu(tib)2]·(H2O)2·Br2}n(1) and {[Cu2(tib)·Br·Cl]·2Br}n(2) were obtained by one pot synthesized of tib with CuBr in the presences of HCl and water. X-ray single crystal diffraction analyses indicate that both complexes 1 and 2 have two dimensional frameworks containing different building blocks. Each Cu(Ⅱ) atom in complex 1 is coordinated by four N atoms from different tib ligands. However, there are two different cryptographic Cu(Ⅱ) atoms in complex 2, one is four coordinated by two bromine atoms and two N atoms from different tib ligands, the other is six coordinated by two chloride atoms and four N atoms from different tib ligands. The thermal gravimetric analysis of complexes 1 and 2 are depicted in the paper.
基金supported by the National Natural Science Foundation of China (20701023 & 51102138)the Natural Science Foundation of Shandong Province, China (BS2010NJ004 &2009ZRB019KH)
文摘Employing unsymmetrical 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,2′-bipyridine as mixed ligands, a new low-dimensional coordination polymer [Zn(MMTA) 2 (2,2′-bipy)] n (MMTA = 2-mercapto-5-methyl-1,3,4-thiadiazole, 2,2′-bipy = 2,2′-bipyridine), has been synthesized under solvothermal condition and characterized by single crystal X-ray diffraction. This compound crys- tallizes in the noncentrosymmetric space group Cc, with cell parameters: a = 8.291(4) , b = 15.483(9) , c = 15.620(6) , = 96.00(5)°, V = 1994.1(2) 3 , and Z = 4. The mixed ligands link the zinc center into a mononuclear unit, which is futher linked by weak C-H···N and C-H···S hydrogen bonds into a three-dimensional noncentrosymmetric framework. The compound exhibits intense photoluminescence and distinct NLO properties at room temperature. The intensity of the green light produced by the powder sample of the compound is about 3.2 times that produced by KDP powder. On the basis of the results of TG analysis, the structure is thermally stable up to ～260 °C.
