基于叶绿素荧光光谱分析的黄瓜霜霉病害预测模型

为了实现对黄瓜病害的快速无损准确预测,基于激光诱导叶绿素荧光光谱分析技术,建立了温室黄瓜霜霉病害的预测模型.通过测定健康叶片、病菌接种3d叶片和接种6d叶片的光谱曲线,采用一阶导数光谱预处理方法,结合主成分分析数据降维方法对三组光谱数据进行特征信息提取后,建立主成分得分散点图,依据累积贡献率选取10个主成分代替导数光谱...     

A series of multidimensional MOFs incorporating a new N-heterocyclic building block: 5,5′-Di(pyridin-3-yl)-3,3′-bi(1,2,4-triazole)

Using the N-heterocyclic building block 5,5′-di(pyridin-3-yl)-3,3′-bi(1,2,4-triazole) (3,3′-H₂dbpt), four 3-D coordination polymers with diverse connectivity, [M(3,3′-dbpt)]_n, M=Co (1), M=Ni (2), M=Zn (3), and [Cd₂(3,3′-dbpt)Cl₂]_n (4), were constructed. By changing the central metal ions, 3,3′-H₂dbpt had three different coordination modes. Consequently, 1–3, which are isostructural, have a 3-D 4-connected topology with (4².8⁴) Schläfli symbol. 4 has a 3-D (4, 6)-topology, with (4³.6³)₂(4⁶.6⁶.8³) Schläfli symbol. Both 1 and 2 reveal weak antiferromagnetic behavior. In addition, 3 and 4 exhibit purple and blue emission bands, respectively. These results indicate that 3,3′-H₂dbpt is an excellent multi-connection linker to construct MOFs with interesting structures and properties.     

Synthesis,Crystal Structure and Luminescent Properties of a Nd（Ⅲ） Complex Constructed from 2-Pyridyl-4,5-imidazoledicarboxylic Acid

A new Nd(Ⅲ) coordination polymer [Nd(pidc)(H2O)4]·pidc-·7H2O(1,pidc2-= 2-py-ridyl-4,5-imidazoledicarboxylate) has been synthesized by solvothermal reaction at 120 ℃ and structurally characterized.The complex belongs to triclinic,space group P with a = 9.022(2),b = 13.731(3),c = 13.782(3) ,α = 70.87(3),β = 71.71(3),γ = 71.71(3),V = 1488.6(7) 3,Z = 2,Dc = 1.798 g/cm3,S = 1.04,μ = 1.839 mm-1,F(000) = 814,Mr = 805.76,Rint = 0.081 and wR = 0.1644 for 5242 observed reflections(I > 2(I)).Each Nd3+ ion is nine-coordinated by five O atoms from three pidc ligands,and four O atoms from lattice water molecules.Each pidc is coordinated to three Nd3+ ions with a μ3-κO:κO':κO",κO'"-μ2 coordination mode into 1D chains,which can be further built into a 3D framework through intermolecular N-H···O and O-H···O hydrogen bonds.Photolu-minescent studies have shown that 1 exhibits emission at 439 nm(λex = 395 nm).     

Crystal Structure and Luminescent Properties of a Zn(Ⅱ) Coordination Polymer Assembled by Mixed-ligand

A Zn(Ⅱ) coordination polymer [Zn(NIP)(3,3'-bpt)]·H2O(1, NIP = 5-nitroisophthalate, 3,3'-bpt = 1H-3,5-bis(3-pyridyl)-1,2,4-triazolate) has been synthesized by the hydrothermal reaction at 140 ℃ and structurally characterized by IR spectroscopy, X-ray diffraction, thermal analysis, single-crystal X-ray diffraction and luminescent properties. In complex 1, the zinc atom is five-coordinated with three carboxylate oxygen atoms from three H2 NIP and two nitrogen atoms from two 3,3'-bpt, respectively, forming a distorted trigonal bipyramidal geometry and showing a 1D chain structure, which is further bridged by NIP to form a 3D supramolecular network via self-assembly of hydrogen bonds.     

Synthesis and Crystal Structure of a Cu(Ⅱ) Coordination Polymer: [Cu(L)(1,10-phen)]_n

A new complex [Cu(L)(1,10-phen)]n(1, L = N-3-pyridine sulfonyl amino acid) has been synthesized and characterized by IR, elemental analysis and X-ray diffraction analysis, and its crystal belongs to monoclinic, space group P21/c with a = 11.481(2), b = 18.094(4), c = 8.5198(17) , β = 102.26(3)°,V = 1729.5(6) 3, Z = 4, Dc = 1.759 g/cm3, F(000) = 932, μ = 1.422 mm-1, R = 0.0368 and wR = 0.0893. In 1, the Cu(Ⅱ) ion adopts a slightly distorted five-coordinated square pyramidal geometry. The L2- ligand adopts O of the carboxyl bridging adjacent Cu(Ⅱ) units to form an infinite chain structure along the c axis. Also, π-π stacking interactions between the adjacent chains expanded the 1-D structures into a 3-D supramolecular structure.     

Synthesis and Crystal Structure of a Novel 1D Magnesium (Ⅱ) Coordination Polymer Constructed by L-Cysteic Acid

A novel coordination polymer [Mg(L)(H2O)2]·H2O] (LH2=L-cysteic acid) has been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction.The crystal crystallizes in orthorhombic system, space group P212121, with a=5.962(3), b=11.224(6), c=13.664(7)(A), V=914.3(8) (A)3, Z=4, Mr=245.50, Dc=1.783 g/cm3,μ=0.445 mm-1,flack parameter=0.32(16), F(000)=512, the final R=0.0458 and wR=0.1172 for 1578 observed reflections with I ＞ 2σ(Ⅰ). The Mg(Ⅱ) atom shows an octahedral geometry defined by two carboxyl O atoms from two different L-cysteic acid ligands, one carboxyl O atom and one amino N atom from the adjacent ligand, and two aqua ligands. The Mg(Ⅱ) atoms are bridged by L-cysteic acid ligands, leading to a 1D infinite zigzag chain. In the structure there are extensive hydrogen bonds,through which the complex completes its 3D framework structure.     

Synthesis and Crystal Structure of a Novel 1D Magnesium （Ⅱ） Coordination Polymer Constructed by L-Cysteic Acid

A novel coordination polymer [Mg(L)(H2O)2]·H2O] (LH2=L-cysteic acid) has been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction.The crystal crystallizes in orthorhombic system, space group P212121, with a=5.962(3), b=11.224(6), c=13.664(7)(A), V=914.3(8) (A)3, Z=4, Mr=245.50, Dc=1.783 g/cm3,μ=0.445 mm-1,flack parameter=0.32(16), F(000)=512, the final R=0.0458 and wR=0.1172 for 1578 observed reflections with I ＞ 2σ(Ⅰ). The Mg(Ⅱ) atom shows an octahedral geometry defined by two carboxyl O atoms from two different L-cysteic acid ligands, one carboxyl O atom and one amino N atom from the adjacent ligand, and two aqua ligands. The Mg(Ⅱ) atoms are bridged by L-cysteic acid ligands, leading to a 1D infinite zigzag chain. In the structure there are extensive hydrogen bonds,through which the complex completes its 3D framework structure.     

Synthesis,structures, and properties of a family of 3d-based MOFs constructed from mixed ligands

Transition Metal Chemistry - By the use of co-ligands tri(2-carboxyethyl)-isocyanurate) (H3tci) and 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (3,4′-bpt), three coordination complexes,...     

A Self-assembled T4（2）5（2） Water Tape Stabilized by a Nickel（II） Complex with L-cysteic Acid

An interesting T4(2)5(2) water tape formed by fused cyclic water pentamers and tetramer was self-assembled in a new inorganic host [Ni(L)(phen)2]·5H2O (L = L-cysteic acid) and characterized by X-ray diffraction. Each [Ni(L)(phen)2] molecule crystallizes with five water molecules with a molecular formula of [Ni(L)(phen)2]·5H2O. The T4(2)5(2) water tape and [Ni(L)(phen)2] molecules assemble into a network of water tapes sandwiched between [Ni(L)- (phen)2] tapes. The network is stabilized by π-π stacking between [Ni(L)(phen)2] molecules and three types of hydrogen-bonding interactions between [Ni(L)(phen)2] molecules, water molecules, and water and [Ni(L)(phen)2] molecules.