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4. Medicinal Chemistry of Nucleic Acids

Author

Lihe Zhang, Zhen Xi, Jyoti Chattopadhyaya, Li-He Zhang, Zhen Xi, Jyoti Chattopadhyaya and Lihe Zhang, Zhen Xi, Jyoti Chattopadhyaya, Li-He Zhang, Zhen Xi, Jyoti Chattopadhyaya

Published
2011

7. BaM(BS3)S (M = Sb, Bi): Two New Thioborate Compounds with One-Dimensional Polymeric Chain Structure

Author

Geng, Lei, Cheng, Wen-Dan, Zhang, Wei-Long, Lin, Chen-Sheng, Zhang, Hao, Li, Ye-Yu, and He, Zhang-Zhen

Abstract

Two new quaternary thioborate compounds with strongly one-dimensional growth, BaSb(BS3)S and BaBi(BS3)S, have been synthesized using the conventional solid state reaction method in closed tubes at 1100 K. The single crystal X-ray diffraction analysis has shown that compound BaSb(BS3)S crystallizes in space group Pnmaof the orthorhombic system with unit cell parameters of a= 9.6898(15) Å, b= 6.2293(13) Å, c= 11.670(2) Å, V= 704.4(2) Å3, and Z= 4, while compound BaBi(BS3)S crystallizes in space group C2/mwith unit cell parameters of a= 14.9890(17) Å, b= 6.2457(6) Å, c= 7.5591(9) Å, β = 101.604(5)°, V= 693.19(13) Å3, and Z= 4. The two compounds both crystallize in the structure of infinite one-dimensional chains with [BS3]3−trigonal plane coordination alternately bridged by [MS3]3−(M = Sb, Bi) trigonal pyramids through sharing two sulfur atoms along the crystallographic baxis. First-principles electronic structure calculations performed with the density functional theory (DFT) method show that the calculated band gaps of BaSb(BS3)S and BaBi(BS3)S are 2.29 and 2.16 eV, respectively, which are in good agreement with the experimental values estimated from UV−vis absorption spectra using the Kubelka−Munk equation, and the observed absorption peak is assigned as charge transfers from S-3p states to Sb-5p (Bi6p) states.

Published
2024
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9. Two spin-canted antiferromagnetic orderings and a field-induced metamagnetic transition in SrMn2(VO4)2(H2O)2.

Author

Zhang, Su-Yun, Guo, Wen-Bin, and He, Zhang-Zhen

Subjects
METAMAGNETISM, ANTIFERROMAGNETIC materials, SPACE groups
Abstract

A new vanadate SrMn2(VO4)2(H2O)2 was synthesized and characterized by single-crystal X-ray analysis. It crystallizes in the monoclinic system with space group C2/m, and exhibits a quasi-one-dimensional (1D) structure. The Mn2+ ions form infinite linear-chains along the b-axis through edge-sharing oxygen atoms and further the linear-chains are connected by VO4 polyhedra into a layer in the ab-plane with Sr2+ ions residing in the space between the layers. Magnetic measurement results show that SrMn2(VO4)2(H2O)2 possesses two spin-canted antiferromagnetic orderings at ∼45 K and ∼7 K. The first ordering at ∼45 K possibly corresponds to a small deviation of spins from a strictly antiparallel arrangement. As the temperature decreases, further spin rotations occur leading to a steadier noncollinear antiferromagnetic phase, leading to the second ordering at ∼7 K. Also, a field-induced transition is observed at a critical field (0.4 T) below ∼7 K. [ABSTRACT FROM AUTHOR]

Published
2019
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11. PbGa2MSe6 (M = Si, Ge) : Two Exceptional Infrared Nonlinear Optical Crystals

Author

Luo, Zhong-Zhen, Lin, Chen-Sheng, Cui, Hong-Hua, Zhang, Wei-Long, Zhang, Hao, Chen, Hong, He, Zhang-Zhen, Cheng, Wen-Dan, Luo, Zhong-Zhen, Lin, Chen-Sheng, Cui, Hong-Hua, Zhang, Wei-Long, Zhang, Hao, Chen, Hong, He, Zhang-Zhen, and Cheng, Wen-Dan

Abstract

Two noncentrosymmetric (NCS) quaternary selenides, PbGa2SiSe6 (1) and PbGa2GeSe6 (2), with second-order nonlinear optical (NLO) responses, were synthesized by a conventional high-temperature solid-state reaction method. Compounds 1 and 2 are constructed by three NCS chromophores, [PbSe4], [GaSe4], and [Ga/SiSe4] or [Ga/GeSe4], with the covalent interactions between the X and Se atoms (X = Pb, Ga, Ga/Si, or Ga/Ge). They crystallize in the polar space groups Cc and Fdd2, respectively. Inspiringly, compound 2 is phase-matchable (PM) and shows high laser-induced damage threshold (LIDT) of 3.7 x AgGaS2 and wide transparent region (0.6325 mu m) in the mid-infrared (MIR) region. Most importantly, it presents extraordinary strong second harmonic generation (SHG) at 2.05 mu m radiation of about 12 x AgGaS2 at the particle size of 2545 mu m, which represents the strongest SHG among PM chalcogenides to date. The calculated major SHG tensor elements of compounds 1 and 2 are d31 = 224.7 and d12 = 222.1 pm/V, respectively, while the calculated d36 of AgGaS2 is only 21.2 pm/V., AuthorCount:8

Published
2015
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19. Magnetic Tuning of an Anionic CoII-MOF through Deionization of the Framework: Spin-Canting, Spin-Flop, and Easy-Plane Magnetic Anisotropy.

Author

Tian, Chong ‐ Bin, Han, Yun ‐ Hu, He, Zhang ‐ Zhen, and Du, Shao ‐ Wu

Subjects
MOLECULAR structure of metal-organic frameworks, COBALT, MAGNETIC properties of metals, DIMETHYLAMINE, MAGNETIC anisotropy, MORIN transition
Abstract

An anionic CoII-MOF, (Me2NH2)[Co3(Me2NH)3(OH)(SDBA)3] ( 1) (H2SDBA=4,4′-sulfonyldibenzoic acid) consisting of highly symmetric CoII3(μ3-OH) triangles exhibits spin-canting, spin-flop, and easy-plane magnetic anisotropy. Measurement on a single crystal shows that the ab plane of 1 is the easy magnetization plane. After structural modification through simultaneous removal of the coordinated dimethylamine (DMA) molecule at the Co center and the ionic groups DMA+ and OH−, the resulting neutral amorphous framework 2 displays an enhanced spin frustration effect. The deionization of 1 does not result in the collapse of the framework, showing the high stability of the backbone structure. [ABSTRACT FROM AUTHOR]

Published
2017
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31. A frustrated ferrimagnet Cu5(VO4)2(OH)4 with a 1/5 magnetization plateau on a new spin-lattice of alternating triangular and honeycomb strips.

Author

Zhang, Su-Yun, Guo, Wen-Bin, Yang, Ming, Tang, Ying-Ying, Cui, Mei-Yan, Wang, Nan-Nan, and He, Zhang-Zhen

Subjects
FERRIMAGNETIC materials, HONEYCOMB structures, ANTIFERROMAGNETIC materials, X-ray diffraction, SCANNING electron microscopes, ENERGY dispersive X-ray spectroscopy
Abstract

Cu5(VO4)2(OH)4 (turanite) is a layered compound, exhibiting a copper(ii) oxide layer in the [0 1 1] plane composed of edge-sharing CuO6 octahedra. Each Cu–O layer is further separated by VO4 tetrahedra. Closer scrutiny found that the copper(ii) oxide layer in the compound represents a totally new geometrically-frustrated lattice, a 1/6 depleted triangular lattice. More specifically, the spin network in the [0 1 1] plane is formed by the alternate ranking of triangular and honeycomb strips. Magnetic measurements show that the Cu5(VO4)2(OH)4 behaves as a spin-1/2 ferrimagnet with a Tc = ∼4.5 K. It exhibits an unusual 1/5 magnetization plateau arising from the competition between antiferromagnetic and ferromagnetic interactions caused by the strong frustration. The possible spin-arrangements are also suggested. [ABSTRACT FROM AUTHOR]

Published
2015
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