The title compound of karounidiol (C30H48O2), a main active triterpene component of snakegourd seed, was isolated from unsaponifiable matter of the seed oil of Trichosanthes kirilowii Maxim., and characterized by X-ra...The title compound of karounidiol (C30H48O2), a main active triterpene component of snakegourd seed, was isolated from unsaponifiable matter of the seed oil of Trichosanthes kirilowii Maxim., and characterized by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with C30H48O2CH3OHH2O (C31H54O4), a = 7.515(1), b = 14.407(1), c = 27.799(2) , V = 3009.8(5) 3, Z = 4, Dx = 1.087 g/cm3, Mr = 490.77, F(000) = 1088 and = 0.086 mm-1. The final R = 0.0840 and wR = 0.2289 for 2752 observed reflections (|F|2 ≥ 2|F|2). The molecular crystal structure of karounidiol shows relative stereochemistry of (3,13,14, 20)-3,29-dihydroxy-13-methyl-26-norolean-7,9(11)-diene. The molecule is composed of five six- membered rings with ring junctures of A/B trans, C/D trans and D/E cis.展开更多
A novel compound [(CH 3CH 2) 4N] 4[(La 12 (OH) 12 MoO 29 )] was synthesized by hydrothermal reaction. The single crystal X ray diffraction shows that the compound crystallized in the monoclinic space group C2/c ; a =2...A novel compound [(CH 3CH 2) 4N] 4[(La 12 (OH) 12 MoO 29 )] was synthesized by hydrothermal reaction. The single crystal X ray diffraction shows that the compound crystallized in the monoclinic space group C2/c ; a =2 5729(4) nm, b =1 4318(1) nm, c =2 1217(4) nm, β =111 56(1)°, V =6 8235(7) nm 3, Z =4, R =0 0751. The basic building blocks of the crystal structure included one MoO 5 hexahedron and twelve LaO 6 octahedra which shared a common edge to form a [(La 12 (OH) 12 MoO 29 )] 4- unit. These units were held together by the [(CH 3CH 2) 4N] + ions.展开更多
Based on some necessary conditions for double pyramidal central configurations with a concave pentagonal base, for any given ratio of masses, the existence and uniqueness of a class of double pyramidal central configu...Based on some necessary conditions for double pyramidal central configurations with a concave pentagonal base, for any given ratio of masses, the existence and uniqueness of a class of double pyramidal central configurations with a concave pentagonal base in 7-body problems are proved and the range of the ratio between radius and half-height is obtained, within which the 7 bodies involved form a central configuration or form uniquely a central configuration.展开更多
The title complex [Yb2Cu3 （O2CCH2CI ）12 （H2O）8]·2H2O（Mr=1838. 73） crystallized in monoclinic space group P21/c, with a=10. 424 （6 ）, b= 17.953（4）, c=15. 193（4）A, β=100. 18（1）, V=2798（2） A3, Z=2, ...The title complex [Yb2Cu3 （O2CCH2CI ）12 （H2O）8]·2H2O（Mr=1838. 73） crystallized in monoclinic space group P21/c, with a=10. 424 （6 ）, b= 17.953（4）, c=15. 193（4）A, β=100. 18（1）, V=2798（2） A3, Z=2, Dc=2.18 g/cm3, R=0. 066, Rw=0. 081 for 3653 unique reflections with I＞ 3（I）, u=50. 9cm-1, F （000）=1782, in which the Cu and Yb atoms are bridged uniquely bychloroacetate groups. The Cu atoms display two types of coordination spheres, a fourcoordinate distorted square and a five-coordinate square pyramid, and the coordinationgeometry of each Yb atom is a square antiprism.展开更多
基金the State Science and Technology Commission (No. 96-903-02-02)
文摘The title compound of karounidiol (C30H48O2), a main active triterpene component of snakegourd seed, was isolated from unsaponifiable matter of the seed oil of Trichosanthes kirilowii Maxim., and characterized by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with C30H48O2CH3OHH2O (C31H54O4), a = 7.515(1), b = 14.407(1), c = 27.799(2) , V = 3009.8(5) 3, Z = 4, Dx = 1.087 g/cm3, Mr = 490.77, F(000) = 1088 and = 0.086 mm-1. The final R = 0.0840 and wR = 0.2289 for 2752 observed reflections (|F|2 ≥ 2|F|2). The molecular crystal structure of karounidiol shows relative stereochemistry of (3,13,14, 20)-3,29-dihydroxy-13-methyl-26-norolean-7,9(11)-diene. The molecule is composed of five six- membered rings with ring junctures of A/B trans, C/D trans and D/E cis.
基金Supported by the National Natural Science Foundation of China(No.2 0 1710 10 )
文摘A novel compound [(CH 3CH 2) 4N] 4[(La 12 (OH) 12 MoO 29 )] was synthesized by hydrothermal reaction. The single crystal X ray diffraction shows that the compound crystallized in the monoclinic space group C2/c ; a =2 5729(4) nm, b =1 4318(1) nm, c =2 1217(4) nm, β =111 56(1)°, V =6 8235(7) nm 3, Z =4, R =0 0751. The basic building blocks of the crystal structure included one MoO 5 hexahedron and twelve LaO 6 octahedra which shared a common edge to form a [(La 12 (OH) 12 MoO 29 )] 4- unit. These units were held together by the [(CH 3CH 2) 4N] + ions.
基金Natural Science Foundation of China (No.19871096)
文摘Based on some necessary conditions for double pyramidal central configurations with a concave pentagonal base, for any given ratio of masses, the existence and uniqueness of a class of double pyramidal central configurations with a concave pentagonal base in 7-body problems are proved and the range of the ratio between radius and half-height is obtained, within which the 7 bodies involved form a central configuration or form uniquely a central configuration.
文摘The title complex [Yb2Cu3 （O2CCH2CI ）12 （H2O）8]·2H2O（Mr=1838. 73） crystallized in monoclinic space group P21/c, with a=10. 424 （6 ）, b= 17.953（4）, c=15. 193（4）A, β=100. 18（1）, V=2798（2） A3, Z=2, Dc=2.18 g/cm3, R=0. 066, Rw=0. 081 for 3653 unique reflections with I＞ 3（I）, u=50. 9cm-1, F （000）=1782, in which the Cu and Yb atoms are bridged uniquely bychloroacetate groups. The Cu atoms display two types of coordination spheres, a fourcoordinate distorted square and a five-coordinate square pyramid, and the coordinationgeometry of each Yb atom is a square antiprism.
