Synthesis and Structural Characterization of a Cobalt Coordination Polymer with Formate and Bis(4-(1H-imidazol-1-yl)phenyl)methanone Ligands

Crystallography Reports - A cobalt coordination polymer, {[Co(L1)2(H2O)2] · (HCOO)2 · H2O}n, where L1 is a bis(4-(1H-imidazol-1-yl)phenyl)methanone, has been synthesized and characterized...     

Boundary value problems for first order impulsive delay differential equations with a parameter

In this paper, by means of the method of upper and lower solutions and monotone iterative technique, the existence of maximal and minimal solutions of the boundary value problems for first order impulsive delay differential equations is established.     

一类具无穷时滞泛函微分方程的周期解

讨论具有无穷时滞中立型泛函微分方程$ \frac{\rm d}{{\rm d}t}\left(x(t)-\int_{-\infty}^{0}g(s,x(t+s)){\rm d}s\right) =A(t,x(t))x(t)+f(t,x_t)$的周期解问题,利用重合度理论中的延拓定理得到了周期解的存在性和唯一性条件;特别地,当$g(s,x)\equiv 0, A(t,x)=A(t)$时, 给出了存在唯一稳定周期解的条件.     

颜色可区分的氰桥五边形带经亲铜作用聚集的异金属多形体

水热条件下,环境友好的K₂[Ni(CN)₄]能缓慢水解形成cis-[Ni(CN)₂(H₂O)₄]单元和氰基配体,并进一步与金属铜(Ⅰ)原子组装形成异金属的五边形带。这些五边形带通过亲铜聚集作用形成二维有色的超分子多形体[(CuCN)₂Ni(CN)₂(H₂O)₄](1和2)。研究发现,低温条件下形成了密集态的深蓝色的化合物1,然而高温反应条件形成疏松态的紫色化合物2,这一现象与高温高压的反应条件形成密集态的物质这一规律相违背。结构的进一步分析发现五边形环尺寸的微小改变和二维超分子层间距离的差异是引起这一反常的原因。除此之外,这两个新的化合物也是少见的由亲铜性聚集作用诱导的着色异常的多形体的例子,显示了从深蓝色到紫色的颜色改变。磁性研究证实了平面正方形的[Ni(CN)₄]^2-中的金属镍(Ⅱ)转换成了有着基态自旋S=1的八面体配位几何中心。     

Effects of Coverage,Water, and Defects on Catechol/TiO2 Interface

Catechol adsorbed on TiO₂ is one of the simplest models to explore the relevant properties of dye-sensitized solar cells. However, the effects of water and defects on the electronic levels and the excitonic properties of the catechol/TiO₂ interface have been rarely explored. Here, we investigate four catechol/TiO₂ interfaces aiming to study the influence of coverage, water, and defects on the electronic levels and the excitonic properties of the catechol/TiO₂ interface through the first-principles many-body Green's function theory. We find that the adsorption of catechol on the rutile (110) surface increases the energies of both the TiO₂ valence band maximum and conduction band minimum by approximately 0.7 eV. The increasing coverage and the presence of water can reduce the optical absorption of charge-transfer excitons with maximum oscillator strength. Regarding the reduced hydroxylated TiO₂ substrate, the conduction band minimum decreases greatly, resulting in a sub-bandgap of 2.51 eV. The exciton distributions in the four investigated interfaces can spread across several unit cells, especially for the hydroxylated TiO₂ substrate. Although the hydroxylated TiO₂ substrate leads to a lower open-circuit voltage, it may increase the separation between photogenerated electrons and holes and may therefore be beneficial for improving the photovoltaic efficiency by controlling its concentration. Our results may provide guidance for the design of highly efficient solar cells in future.     

Syntheses,Structural Characterization of Two Cobalt Coordination Polymers Composed of Isophthalate and Bis(4-(1H-imidazol-1-YL)phenyl)methanone Ligands

Russian Journal of Coordination Chemistry - Two 2D cobalt complexes, namely {[(Bipmo)2Co2(Ipa)2](DMF)]·2.25H2O}n (I), {[(Bipmo)-Co(Ipa)]·2H2O}n (II), have been constructed solvothermally...     

Structure and Adsorption Properties to TVOC of Orange Peel Modified with KOH

Food waste orange peel was employed as a raw material to prepare biomass adsorbent to solve the indoor Total Volatile Organic Compounds(TVOC). The preparation process of orange peel treated with KOH was optimized by the quadratic regression orthogonal rotation, and the regression model and optimal processing conditions were obtained. The structure of the adsorbent was characterized by BET, SEM, TEM, EDS, XRD and FTIR analysis. The adsorption properties and desorption regeneration were discussed. The results showed the maximal removal rate Ymax was 9.4824% when KOH concentration was 0.3 mol/L, the soaking time of KOH was 26 h and that of HCl was 2.89 h. The best single factor condition was the adsorbent with 40 mesh size and 6.0 g. The adsorption of modified orange peel on TVOC conformed to the Freundlich models, which was more inclined to multi-layer active site adsorption. The adsorption law followed the quasi-second-order kinetic model(R~2 = 0.955), indicating the adsorption was a physico-chemical mixture but controlled by physical adsorption and it was a spontaneous endothermic process. The modified orange peel exposed more sites and had stronger chemical groups, which were beneficial to adsorption. The adsorbent has a significantly better TVOC removal rate than other materials at 1% level, that is, modified orange peel diatomite activated carbon bamboo charcoal macroporous resin. In addition, it had good recycling and regeneration capacity.