Synthesis,Structure and Photoluminescence of Co-crystal of Bis[2-(benz(oxa/imida)zol-2-yl)phenolato-κ2N,O]zinc(Ⅱ) Being Site Occupancy Disorder with a Heteroatom Ratio of NH to O (0.408/0.592)

The zinc(Ⅱ) complex with Hpbx (Hpbx = 2-(benzoxazol-2-yl)phenol) and Hpbm (Hpbm=2-(benzimidazol-2-yl)phenol),namely[Zn(pbm)2]1.633[Zn(bpx)2]2.367·DMF·2H2O1,has been synthesized and characterized by X-ray crystallography,FTIR and elemental analysis.The coordination structures are statistically disordered and can be regarded as a co-crystal of [Zn(pbm)2]and [Zn(pbx)2] with the ratio of ca.0.408/0.592.Solvate water and DMF molecules are also present in the lattice.Crystal data for 1:monoclinic,space group P21/c,Mr= 2049.02,Z = 2,α = 9,7571(6),b = 25.6415(16),c = 19.8675(10)(A),β = 111.342(2)°,V = 4629.7(5) (A)3,Dc = 1.470 g/cm3,μ =1.100 mm-1,F(000) = 2104,R = 0.0575 and wR = 0.1282 for 5528 observed reflections (I＞ 2σ(I)).The photoluminescent spectra for this compound have also been studied.     

Application of the pKa rule to synthesize salts of bezafibrate

ABSTRACT

Co-crystallization frequently employs forces such as hydrogen bonds, halogen bonds, and π-π stacking to assemble molecules in a multi-component crystal. In an effort to increase the strength of the intermolecular interaction between the anti-cholesterol drug bezafibrate (BEZA), a wastewater contaminant, and hydrogen-bond-acceptor molecules, we modified the pK_a values of the acceptors. Here, we describe the first series of salts incorporating BEZA and achieve a variety of supramolecular architectures including discrete assemblies, 1D chains, tapes, and 2D sheets. We discuss exceptions to the pK_a rule, and demonstrate that the presence of hydrogen-bond-donor atoms on the acceptor molecule supports salt formation.     

Synthesis, Structure and Geometrical Calculation of a Novel Co-crystal of {[4-Bromo-2-(benzimidazol-2-yl)phenolato][2- (1-butylbenzimidazol-2-yl)phenolato]zinc(Ⅱ)] and Bis[μ-2- (1- butylbenzimidazol-2-yl)phenolato]- 1κN3: 2κO; 1κO:2κN3-bis{[2-(1-butylbenzimidazol-2-yl)phenolato-κ2N3,O]zinc(Ⅱ)}

The title compound has been synthesized and characterized crystallographically. It is a co-crystal consisting of two different neutral zinc(Ⅱ) complexes with Hbpbm (Hbpbm = 4-bromo-2-(benzimidazol-2-yl)phenol) and Hnpbm (Hnpbm = 2-(1-butylbenzimidazol-2-yl)phenol).One is a monomeric mixed-ligand complex of [Zn(bpbm)(npbm)] 1 and the other a dimer of[Zn2(npbm)4] 2 with their ratio of 2:1. Thus the overall formula for the title compound is 21·2.Adjacent 1 and 2 are connected to each other by intermolecular hydrogen bonding interactions in the lattice. The crystal data: monoclinic, space group P21/c, a= 15.0141(12), b = 20.9941(17), c =18.4686(15) (A), β = 97.445(2)°, V= 5772.4(8) (A)3, Mr= 2429.68, Z = 2, Dc = 1.398 g/cm3,μ = 1.579mm-1, F(000) = 2504, R = 0.0637 and wR = 0.1771 for 6464 observed reflections (I＞ 2σ(Ⅰ)). The geometrical structure for 1 has also been theoretically optimized and compared with the experimental one.     

Dihydrofolate Reductase Inhibitors: The Pharmacophore as a Guide for Co-Crystal Screening

In this work, co-crystal screening was carried out for two important dihydrofolate reductase (DHFR) inhibitors, trimethoprim (TMP) and pyrimethamine (PMA), and for 2,4-diaminopyrimidine (DAP), which is the pharmacophore of these active pharmaceutical ingredients (API). The isomeric pyridinecarboxamides and two xanthines, theophylline (THEO) and caffeine (CAF), were used as co-formers in the same experimental conditions, in order to evaluate the potential for the pharmacophore to be used as a guide in the screening process. In silico co-crystal screening was carried out using BIOVIA COSMOquick and experimental screening was performed by mechanochemistry and supported by (solid + liquid) binary phase diagrams, infrared spectroscopy (FTIR) and X-ray powder diffraction (XRPD). The in silico prediction of low propensities for DAP, TMP and PMA to co-crystallize with pyridinecarboxamides was confirmed: a successful outcome was only observed for DAP + nicotinamide. Successful synthesis of multicomponent solid forms was achieved for all three target molecules with theophylline, with DAP co-crystals revealing a greater variety of stoichiometries. The crystalline structures of a (1:2) TMP:THEO co-crystal and of a (1:2:1) DAP:THEO:ethyl acetate solvate were solved. This work demonstrated the possible use of the pharmacophore of DHFR inhibitors as a guide for co-crystal screening, recognizing some similar trends in the outcome of association in the solid state and in the molecular aggregation in the co-crystals, characterized by the same supramolecular synthons.     

以5-(3-吡啶基)-1H-吡唑-3-羧酸为配体的钴共晶配合物的合成、晶体结构及电化学性质

采用溶剂热法合成了一种新型的钴（Ⅱ）基配合物,即{[Co（Hppc）₂][Co₂（4,4''-bipy）（H₂O）₄]（SO₄）₂·2H₂O}_n （1）,其中H₂ppc=5-（3-吡啶基）-1H-吡唑-3-羧酸,4,4''-bipy=4, 4''-联吡啶。配体H₂ppc是由吡啶环、吡唑环和羧基共同组成,同时兼具了刚性和柔性。通过单晶X射线衍射对配合物1进行了结构测定。结果显示所合成的配合物1结晶在单斜晶系C2/c空间群,包括2个晶体学独立部分：二维层状[Co（Hppc）₂]和一维链状[Co₂（4,4''-bipy）（H₂O）₄]^2-,并形成具有{4⁴·6²}{4}₂拓扑网络结构的共晶化合物。此外,配合物1呈现出良好的电化学发光（ECL）性能以及良好的超级电容器性能。     

Resolution of Halogenated Mandelic Acids through Enantiospecific Co-Crystallization with Levetiracetam

The resolution of halogenated mandelic acids using levetiracetam (LEV) as a resolving agent via forming enantiospecific co-crystal was presented. Five halogenated mandelic acids, 2-chloromandelic acid (2-ClMA), 3-chloromandelic acid (3-ClMA), 4-chloromandelic acid (4-ClMA), 4-bromomandelic acid (4-BrMA), and 4-fluoromandelic acid (4-FMA), were selected as racemic compounds. The effects of the equilibrium time, molar ratio of the resolving agent to racemate, amount of solvent, and crystallization temperature on resolution performance were investigated. Under the optimal conditions, the resolution efficiency reached up to 94% and the enantiomeric excess (%e.e.) of (R)-3-chloromandelic acid was 63%e.e. All five halogenated mandelic acids of interest in this study can be successfully separated by LEV via forming enantiospecific co-crystal, but the resolution performance is significantly different. The results showed that LEV selectively co-crystallized with S enantiomers of 2-ClMA, 3-ClMA, 4-ClMA, and 4-BrMA, while it co-crystallized with R enantiomers of 4-FMA. This indicates that the position and type of substituents of racemic compounds not only affect the co-crystal configuration, but also greatly affect the efficiency of co-crystal resolution.     

Crystal Structures of Bis[aquachlorotriphenyltin(Ⅳ)] dihydrate·1,4,7,10,13,16-hexacyclooctadecane bis[aquachlorotriphenyltin(Ⅳ)]·1,4,7,10,13,16-hexacyclooct-adecane(3/1) and Bis[aquatrifluoroacetatotriphenyltin(Ⅳ)] dihydrate·1,4,7,10,13,16-hexa

1INTRODUCTIONSeveraldiorganotinchloridesformhydrateswhosecoordinatedwatermoleculesinteractviahydrogenbondswiththecrownethers.Thepolyether,18-crown-6,affordscomplexeshavingtheformulationof[RRSnCl2H2O]2C12H24O6(e.g.,R=R?=CH3[1];R=R?=C6H5[2];R=CH3,R?=C6H5[3]);atin-chlorinebridgeraisesthecoordinationnumberofthemetalatomstosix.Withtriphenyltinchlorideinplaceofthediorganotindichlorides,theouter-spherecoordinationcomplexexistsasanaquachlorotriphenyltinentitythatinteractswiththecrownethe…     

Challenges and Progress in Nonsteroidal Anti-Inflammatory Drugs Co-Crystal Development

Co-crystal innovation is an opportunity in drug development for both scientists and industry. In line with the “green pharmacy” concept for obtaining safer methods and advanced pharmaceutical products, co-crystallization is one of the most promising approaches to find novel patent drugs, including non-steroidal anti-inflammatory drugs (NSAID). This kind of multi-component system improves previously poor physicochemical and mechanical properties through non-covalent interactions. Practically, there are many challenges to find commercially viable co-crystal drugs. The difficulty in selecting co-formers becomes the primary problem, followed by unexpected results, such as decreased solubility and dissolution, spring and parachute effect, microenvironment pH effects, changes in instability, and polymorphisms, which can occur during the co-crystal development. However, over time, NSAID co-crystals have been continuously updated regarding co-formers selection and methods development.     

Effect of Alkyl Groups in Pyrene Chromophore on the Mechanical Response of Pyrene‐Octafluoronaphthalene Co‐Crystals

Changes in the photophysical properties of pyrene ( Py )‐octafluoronaphthalene ( OFN ) co‐crystals ( Py ? OFN ) upon mechanical stimuli are described herein. The Py ? OFN co‐crystal showed a mechano‐induced bathochromic shift in emission, and a similar tendency was observed for the 1,3,6,8‐tetramethylpyrene‐ OFN co‐crystal. These shifts are due to disruption of the microscopic molecular orientation in the co‐crystal, which allows for excimer formation. In sharp contrast to the parent Py ? OFN and methyl‐substituted Py ‐ OFN co‐crystals, no mechano‐induced bathochromic shift was observed when longer alkyl chains were introduced to the 1‐, 3‐, 6‐, and 8‐positions of the Py chromophore. This photophysical opposability against mechanical stimuli could be explained by the orthogonally oriented alkyl groups on the Py ring, which existed between two Py cores like pillars. This fixed OFN to maintain the face‐to‐face alternatively stacked structure of the co‐crystal and thus prevented the formation of the Py excimer. The pillar effect demonstrated herein provides a rational design for co‐crystalline systems that are photophysically stable against mechanical stresses.     

CL20/BTF共晶高温热分解ReaxFF/lg分子动力学模拟

用ReaxFF/lg反应力场模拟CL20/BTF共晶在2000~3000 K高温条件下的热分解过程,获得了势能和物种数的演化、初始反应路径及热分解产物等详细信息。通过指数函数对势能的演化曲线进行拟合得到反映特征时间等参数,采用经典的Arrhenius反应速率方程描述总包反应,获得CL20/BTF共晶的活化能E_a=60.8 kcal/mol。研究得到CL20/BTF共晶热分解的初始路径,CL20分子中N-NO₂首先断裂,在热分解起始阶段占主导作用。在不同温度条件下,CL20分子均在BTF分子前完全分解。CL20/BTF共晶的主要产物为NO₂、NO、NO₃、HNO、N₂、H₂O、CO₂、O₂、N₂O、HONO 等。温度对产物均产生一定程度的影响.