A Six-Coordinate Picrate Nickel(II) Complex Based on the V-Shaped Ligand 1,3-Bis (1-Benzylbenzimidazol-2-yl)-2-Thiapropane: Synthesis,Crystal Structure,Biological Activities

Abstract

A six-coordinate picrate nickel(II) complex based on the V-shaped ligand 1,3-bis(1-benzylbenzimidazol-2-yl)-2-thiapropane (L), with the composition [Ni(L)₂](pic)₂, has been synthesized and characterized systematically. The crystal structure of the Ni(II) complex is a six-coordinated octahedron, which is considerably close to ideal octahedral geometry with N₄S₂ donors of the two ligands. Biological activities of compounds were investigated using electronic absorption spectroscopy, fluorescence spectroscopy, and viscosity measurements. The results suggested that both ligand L and Ni(II) complex bind to DNA in an intercalative binding mode, and DNA-binding affinity of the Ni(II) complex is stronger than that of ligand L.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional figures.]     

A bio‐safe cyclophosphazene derivative flame retardant for polylactic acid composites: Flammability and cytotoxicity

An efficient bio‐safe cyclophosphazene flame retardant, 1,5,9,13,16,20‐Hexaoxa‐7,14,21‐triaza‐6λ⁴,8λ⁴,5λ⁴‐triphosphatrispiro[5.1.5.1.5.1]heneicosa‐6,8(14),15(21)‐triene (HCPO), was synthesized, and then was incorporated into polylactic acid (PLA) to improve the fire safety. The chemical structure of HCPO was confirmed by Fourier‐transformed infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance spectroscopy. The thermal stability of the compound was characterized by thermogravimetric (TG) analyzer. The cytotoxic effects of HCPO to cells were evaluated. Fire behavior and thermal stability of PLA composites were investigated by vertical burning, limiting oxygen index (LOI), TG analysis, and cone calorimeter. The morphology of residual charring was observed by scanning electron microscope. The results showed HCPO was bio‐safe, and highly effective to enhance the flame retardancy of PLA composites. The LOI value was increased from 18.4 to 27.5 and UL‐94 grade achieved V‐0 for the PLA composite containing only 2% HCPO and 2% pentaerythrotol. It was demonstrated that intermolecular cross‐linking reaction between pentaerythrotol and HCPO in high temperature range could accelerate the formation of compact char layers.     

Theoretical studies on electronic spectroscopy and dynamics with the real-time time-dependent density functional theory

Time-dependent density functional theory (TDDFT) has evolved into a general routine to extract the energies of low-lying excited states over the last decades. Driven by the remarkable progress of laser technology, the study of the interaction between matter and intense laser fields with ultrashort pulse duration develops rapidly. A great number of new strong field phenomena emerge. The requirement of a theoretical tool to study the intense field phenomena and dynamical processes of polyatomic systems is urgent. To extend the power of the TDDFT beyond the linear responses, an alternative scheme has been developed by numerically solving the time-dependent Kohn-Sham equations directly in real-time domain. In this article, we summarize the algorithms and capabilities of the real-time TDDFTon studying electron spectroscopy and dynamics of polyatomic systems. The failure of TDDFT with the adiabatic localdensity approximation on some dynamical processes and the possible solutions are synopsized as well. The numerical implementation of algorithms and applications of RT-TDDFT on the linear and nonlinear spectroscopies and electronic dynamics of nano-size nonmetal clusters are displayed.     

巡游出租车运价动态调整系统动力学模型

合理的巡游出租车运价体系是缓解行业矛盾和促进行业良性发展的重要保障.为了充分体现运价在供需调节中的杠杆作用,运用系统动力学构建了巡游出租车运价动态调整模型.以宁波市巡游车和网约车运营数据对模型参数进行标定,验证了模型的有效性;以市场供需平衡为目标,分别模拟了高峰、低峰不同需求水平下动态加价、减价对市场供需平衡状态的影响分析以及不同网约车吸引度水平下巡游出租车运价动态调整策略.模型结果表明:(1)当运价增加0.6元km~(-1)时,可使高峰时段供需接近平衡状态,有效地抑制了高峰需求水平,且保证了巡游车运营总体收益增加;(2)当巡游车和网约车市场业务量之比约为10:4.5和10:8时,巡游车加价分别为0.6和-0.4元km~(-1),当巡游车处于竞争优势时,适度加价可期获得更大收益;处于劣势时,适度降价以提高自身竞争能力.     

Synthesis and crystal structure of a molybdenum complex of fullerene, [Mo(η 2–C60)(CO)2(dpphen)(dbf)·0.63CS2] (dpphen = 4,7-diphenyl-1,10-phenanthroline; dbf = dibutyl fumarate)

The molybdenum complex [Mo( ²-C₆₀)(CO)₂(dpphen)(dbf)] (1) [dpphen = 4,7-diphenyl-1,10-phenanthroline; dbf = dibutyl fumarate] has been prepared and structurally characterized by X-ray diffraction analysis. In the molecule of (1), the coordination geometry of the Mo atom is distorted octahedral with the phen (1,10-phenanthroline) group of dpphen and two CO groups in the equatorial plane. The Mo atom binds in an ²-fashion to the C—C bonds of C₆₀and dbf. The two C—C bonds are almost mutually orthogonal.     

Solving the 3-SAT problem based on DNA computing

The 3-SAT problem is an NP-complete problem, and many algorithms based on DNA computing have been proposed for solving it since Adleman's pioneering work. This paper presents a new algorithm based on the literal string strategy proposed by Sakamoto et al. Simulation results show that the maximal number of literal strings produced during the computing process is greatly reduced. Moreover, the length of the literal strings is also reduced from m to n at most.     

Determination of catecholamines as their N-hydroxy-succinimidyl-3-indolylacetate derivatives by pre-column derivatization HPLC separation and fluorescent detection

N-Hydroxysuccinimidyl-3-indolylacetate (SIIA) is a new fluorescent derivatizing reagent with an indole ring and ?an N-hydroxysuccinimide ester functionality. It can react with catecholamines under mild conditions to form corresponding amides, which have strong fluorescence at λ_ex/λ_em = 301 nm/?365 nm. This paper covers the RP-HPLC separation and fluorescent determination of derivatized catecholamines with SIIA. In a mobile phase of methanol-water (36/64, v/v) containing H₃cit-Na₂HPO₄ buffer (pH = 4.00, 10 mmol/L), the derivatives of norepinephrine (NE), epinephrine (E) and dopamine (DA) were eluted within 15 min on a C₁₈ column. The detection limits were 0.043, 0.13 and 0.18 pmol, respectively, when the ratio of signal to noise (S/N) was 3. The excessive reagent is rapidly hydrolyzed to 3-indolylacetic acid (IA) that can be easily separated from derivatives. Received: 16 April 1999 / Revised: 13 July 1999 / /Accepted: 15 July 1999     

Influence of neodymium on mitochondrial metabolism: a thermokinetic perspective

Journal of Thermal Analysis and Calorimetry - Nd compounds have been widely used for the promotion of growth of plant due to their excellent biophysical and biochemical properties. Mitochondria are...     

Development of New Thiophene-Containing Triaryl Pyrazoline Derivatives as PI3Kγ Inhibitors

A series of new thiophene-containing triaryl pyrazoline derivatives, 3a–3t, were synthesized and evaluated regarding PI3K inhibition activity and anti-tumor potency based on a trial of introducing significant moieties, including pyrazoline and thiophene, and simplifying the parallel ring structures. Most of the tested compounds indicated potent PI3K inhibitory potency, with this series of compounds showing more potency for PI3Kγ than PI3Kα. The top hit 3s seemed more potent than the positive control LY294002 on inhibiting PI3Kγ (IC₅₀ values: 0.066 μM versus 0.777 μM) and more selective from PI3Kα (Index values: 645 versus 1.74). It could be inferred that the combination of para- and meta-, as well as the modification of the electron-donating moieties, led to the improvement in potency. The anti-proliferation inhibitory activity and the enzymatic inhibition potency indicated consistent tendencies. The top hit 3s could inhibit the phosphorylation of Akt by inhibiting PI3K through the PI3K-Akt-mTOR pathway. The molecular docking simulation indicated that the binding pattern of 3s into PI3Kγ was preferable than that of PI3Kα, with more hydrogen bond, more π-involved interactions, and fewer π-sulfur interactions. The information in this work is referable for the further development of selective inhibitors for specific isoforms of PI3K.     

Hyperacmosin R,a New Decarbonyl Prenylphloroglucinol with Unusual Spiroketal Subunit from Hypericum acmosepalum

Two previously undescribed polycyclic polyprenylated acylphloroglucinols, hyperacmosins R-S (1–2), were obtained from the aerial parts of Hypericum acmosepalum. Their structures were elucidated by extensive spectroscopic analysis and electronic circular dichroism calculation (ECD). Compound 1 featured an unprecedented 5,8-spiroketal subunit as well as the loss of C-2′ carbonyl in the phloroglucinol ring. In addition, compounds 1 and 4 showed weak hepatoprotective activity against paracetamol-induced HepG2 cell damage at 10 μm. The plausible biosynthetic pathway of 1 was proposed via a retro-Clasisen reaction and decarboxylation.