微孔配位聚合物的合成与表征

微孔配位聚合物是近年来被广泛研究的领域之一，这类材料在储气材料等领域的应用前景逐步被开发出来。作为良好的储气材料，配位聚合物必须具有规则的孔道结构和良好的稳定性。本论文以合成多维孔道新化合物为目标，成功合成并解析出13个微孔配位聚合物。对化合物的元素分析、红外和TGA等进行了表征，同时对部分化合物的紫外和荧光性质进行了测定。 首先，对微孔配位聚合物的最新研究动态进行了简要介绍，并对一些代表性化合物的结构类型、性能以及应用等进行了归纳总结。然后介绍了合成配位聚合物晶体的实验原理，化合物的表征方法。 本论文在水热条件下，成功合成了13个新化合物分别为：(C19H15N4)2(NO3)2∙3H2O (3-3)，(C19H15N4)2[CdCl4] (3-4)，2Ag(tta)∙AgNO3 (3-5)，Cu8(tta)15(H2O)Cl (3-6)，[Zn(5-CH3-tta)2(isoH)2] (BDC) (3-7)，Pb[(PO3)2C(OH) CH3]•H2O (4-1)，Ni(C5H4NCOO)2∙4H2O (5-2)，Co(C5H4NCOO)2(H2O)2∙2H2O (5-3)，[CdCl2(C13H12N2O)2] (5-4)，{C6H4(COOH)S}2 (5-5)，(Deta)(ClO4)NO3 (5-6)，(NH4)2[-Mo8O26] (6-1) 和 (NH4)2[Mo4O13] (6-2)。其中化合物3-5，3-6和3-7是由四氮唑和金属构筑的纳米孔道三维化合物；化合物3-3，3-4，5-2，5-3，5-4，5-5和5-6均具有超分子网络结构；4-1是有机膦酸为配体的二维层状化合物，是首例(5,5)连接的(47•63) (48•62)拓扑网络。化合物6-1是一维无限链骨架的钼酸盐，6-2是二维层状的钼酸盐，显示了不寻常的(32•4)(32•53•8)(3•42•54•6•82)(34•43•54•64) 拓扑网络。最后对论文进行概括总结，并展望了下一阶段的工作安排。

Ring-opening polymerisation of silver-diphosphine [M2L3] coordination cages to give [M2L3](infinity) coordination polymers

[M2L3] coordination cages and linear [M2L3]infinity polymers of the rigid, bridging diphosphines bis(diphenylphosphino)acetylene (dppa) and trans-1,2-bis(diphenylphosphino)ethylene (dppet) with silver(I) salts have been investigated in the solution and solid states. Unlike flexible diphosphines, 1:1 dppa/AgX mixtures do not selectively form discrete [Ag2(diphos)2(X)2] macrocycles; instead dynamic mixtures of one-, two- and three-coordinate complexes are formed. However, 3:2 dppa/AgX ratios (X = SbF6. BF4, O3SCF3 or NO3) do lead selectively to new [M2L3] triply bridged cage complexes [Ag2(dppa)3(X)2] 1a-d (X = SbF6 a, BF4 b, O3SCF3 c, NO3 d), which do not exhibit Ag-P bond dissociation at room temperature on the NMR time scale (121 MHz). Complexes la-d were characterised by X-ray crystallography and were found to have small internal cavities, helical conformations and multiple intramolecular aromatic interactions. The nucleophilicity of the anion subtly influences the cage shape: Increasing nucleophilicity from SbF6 (1a) through BF4 (1b) and O3SCF3 (1c) to NO3 (1d) increases the pyramidal distortion at the AgP3 centres, stretching the cage framework (with Ag...Ag distances increasing from 5.48 in 1a to 6.21 A in 1d) and giving thinner internal cavities. Crystal packing strongly affected the size of the helical twist angle, and no correlation between this parameter and the Ag-Ag distance was observed. When crystalline 1c was stored in its supernatant for 16 weeks, conversion occured to the isostoichiometric [M2L3]infinity coordination polymer [Ag(dppa)2Ag(dppa)(O3SCF3)2]infinity (1c'). X-ray crystallography revealed a structure with ten-membered Ag2(dppa)2 rings linked into infinite one-dimensional chains by a third dppa unit. The clear structural relationship between this polymer and the precursor cage 1c suggests a novel example of ring-opening polymerisation. With dppet, evidence for discrete [M2L3] cages was also found in solution, although 31P NMR spectroscopy suggested some Ag-P bond dissociation. On crystallisation, only the corresponding ring-opened polymeric structures [M2L3]infinity could be obtained. This may be because the greater steric bulk of dppet versus dppa destabilises the cage and favours the ring-opening polymerisation.

Implication des PPARgamma dans l'effet cardioprotecteur des endocannabinoïdes et du préconditionnement ischémique

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Implication des PPARgamma dans l'effet cardioprotecteur des endocannabinoïdes et du préconditionnement ischémique

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Cannabinoids impact on pregnancy: effects in trophoblast cells

Cannabinoids (CBs) can be classified as: phytocannabinoids, the constituents of the Cannabis sativa plant; synthetic cannabinoids lab-synthesized and the endocannabinoids that are endogenous lipid mediators. Cannabinoid compounds activate cannabinoid receptors – CB1 and CB2. The most prevalent psychoactive phytocannabinoid is Δ9tetrahydrocannabinol (THC), but more than 60 different CBs were already identified in the plant. The best characterized endocannabinoids (eCBs) are anandamide (AEA) and 2arachidonoylglycerol (2-AG), that are involved in several physiological processes including synaptic plasticity, pain modulation, energy homeostasis and reproduction. On the other hand, some synthetic cannabinoids that were initially designed for medical research, are now used as drugs of abuse. During the period of placental development, highly dynamic processes of remodeling occur, involving proliferation, apoptosis, differentiation and invasion of trophoblasts. It is known that a tight control of eCBs levels is required for normal pregnancy progression and that eCBs are involved in trophoblast cells turnover. Therefore, by sharing activation of the same receptors, exposure to exocannabinoids either by recreational or medicinal use may lead to alterations in the eCBs levels and in the endocannabinoid system homeostasis In this work, it was studied the impact of CBs in BeWo trophoblastic cells and in primary cultures of human cytotrophoblasts. Cells were treated for 24 hours with different concentrations of THC, the synthetic cannabinoid WIN‐55,212 (WIN) and 2-AG. Treatment with THC did not affect BeWo cells viability while WIN and 2-AG caused a dose-dependent viability loss. Morphological studies together with biochemical markers indicate that 2-AG is able to induce apoptosis in cytotrophoblasts. On the other hand, morphological studies after acridine orange staining suggest that autophagy may take part in WIN-induced loss of cell viability. All cannabinoids caused a decrease in mitochondrial membrane potential (Δψm) but only 2-AG led to ROS/RNS generation, though no changes in glutathione levels were observed. In addition, ER-stress may be involved in the 2-AG induced-oxidative stress, as preliminary results point to an increase in CCAAT-enhancer-binding protein homologous protein (CHOP) expression. Besides the decrease in cell viability, alterations in cell cycle progression were observed. WIN treatment induced a cell cycle arrest in G0/G1 phase, whereas 2-AG induced a cell cycle arrest in G2/M phase. Here it is reinforced the relevance of cannabinoid signaling in fundamental processes of cell proliferation and cell death in trophoblast cells. Since cannabis-based drugs are the most consumed illicit drugs worldwide and some of the most consumed recreational drugs by pregnant women, this study may contribute to the understanding of the impact of such substances in human reproduction.