The catalytic properties of DNA G‐quadruplexes rely on their structural integrity

The influence of the G‐quartet structural integrity on the catalytic activity of the G‐quadruplex(G4)was investigated by comparing the G4‐DNAzyme performances of a series of G4s with a G‐vacancy site and a G‐triplex(G‐tri).The results presented herein not only confirm that the structural integrity of the 3'‐end G‐quartet is necessary for G4s to be catalytically competent but also show how to remediate G‐vacancy‐mediated catalytic activity losses via the addition of guanine surrogates in an approach referred to as G‐vacancy complementation strategy that is applicable to parallel G4s only.Furthermore,this study demonstrates that the terminal G‐quartet could act as a proximal coordinating group and cooperate with the flanking nucleotide to activate the hemin cofactor.

Crystallographic Characterization of the Novel Inorganic-organic Hybrid Coordinated Polymer: [(C_(22)H_(50)N_2)(Ag_2I_4)]_n

A novel coordinated polymer [(C22H50N2)(Ag2I4)]n([C22H50N2]2+ = N,N?-1,2- ethylence-bis(N,N?-dimethyl octane ammonium) (EDO)) was synthesized by the reaction of AgI and EDO at room temperature with pH = 6.8, and structurally characterized by means of X-ray single- crystal diffraction. It crystallizes in triclinic, space group P1 with a = 9.6080(1), b = 12.7643(2), c = 7.2157(8) ? a = 100.835(8), ?= 91.030(3), ? = 91.297(9)o, (C21.50H48.50Ag2I4N2), Mr = 1058.46, V = 868.71(19) 3, Z = 1, Dc = 2.023g/cm3, F(000) = 497.5, ?MoKa) = 4.692 mm-1, the final R = 0.0623 and wR = 0.1949 for 2641 observed reflections with I > 2s(I). The title compound consists of cations ([C22H50N2]2+) and anion chain (Ag2I42-)∞ which are combined by static attracting forces in the crystal to form the so-called organic-inorganic hybrid material.

Synthesis,Structure and Reaction of a New BitungstenCompound:(Et_4N)_2W_2S_4 (tdt)_2

The new binuclear tungsten compound (Et4N)2W2S4(tdt)2 (H2tdt=H2S2C6H3CH3) (I) with Mr=1067. 97 has been prepared and characterized by IR andX-ray single crystal analysis. Compound (I) has been synthesized by two routes, ofwhich one was from the reaction of (NH4)WS4 with H2tdt, and the other is from lig-and substitution reaction of W2S4 (dip)2 by H2tdt. The compound contains a typical[W2S4j2+ moiety with a W-W bond of 2. 862(2) A. Its crystallographic data are: or-thorhombic, space group Pbca, a=23. 995 (9), b=31. 496 (7), c=10. 537 (5) A, V=7950(8) A3, Z=8, Dc= 1. 78 g·cm-3, p(MoKa)= 63. 37 cm-1 and R=0. 062 for1926 reflections with I≥3d(I). Synthesis, structure and reaction of the compound arediscussed in this paper.

The Synthesis and Crystallographic Characterization of Heterotrimetallic Linear Complex of [Et_4N][ (Ph_3P)_2{CuS_2WS_2Fe} Br_2]

The complex [Et4N][(Ph3P)2{CuS2WS2Fe} Br2] (1 ), C44, H50NBr2CuFeP2S4W, M4= 1246. 13, has been obtained by reaction of [Et4N]2[WS4] andFeBr2 with Cu (Ph3P )3I in MeCN/CH2Cl2. Crystal data for [Et4N][(Ph3P)2{CuS2WS2Fe) Br2] (1): triclinic, P1, Z = 2, a= 13. 495 (7), b = 15. 322 (5), c =12. 361 (4), a=105. 32(3), β=93. 19(4), γ=101. 35(4) and V=2401. 2 The bond lengths of W-Fe bond and the W-Cu distance are 2. 793(2) A and 2. 823(2), respectively. Three kind metal atoms of the title structure [Et4N][(Ph3P)2{CuS2WS2Fe}Br2] (1) are nearly distributed along a line, and along which three metalatoms (W, Cu, Fe) are approximately tetrahedral coordination.

A new barium-containing alkali metal silicate fluoride NaBa3Si2O7F with deep-UV optical property

A new silicate fluoride,NaBa3 Si207 F,has been successfully synthesized by a high-temperature solution method.It crystallizes in the orthorhombic space group Cmcm(No.63).NaBa3 Si2 O7 F is the first barium-containing alkali metal silicate fluoride with the[NaO6]polyhedra,the[BaO8 F]polyhedra and isolated[Si2 O7]units.The optical characterizations indicate that NaBa3 Si2 O7 F possesses wide transparent window and available luminescence properties.To confirm the coordination surroundings of anionic groups and its thermostability,infrared spectroscopy and thermal behaviors were also analyzed,which proved the existence of tetrahedronly coordinated silicium atoms and the good stability of NaBa3 Si2 O7 F at high temperature.First-principles calculation was also implemented for better understanding the relationship between the structure of NaBa3 Si207 F and its property.Additionally,to further explore the structural novelty of NaBa3 Si2 O7 F,the comparison of the anionic structures was carried out in mixed alkali and alkaline-earth metal silicate fluorides.Interestingly,the result indicates the isolated[Si2 O7]dimer is rare among the above systems,which enriches the structural chemistry of silicate fluorides.