The synthesis of highly porous organic polymers with predefined porosity has attracted considerable attention due to their potential in a wide range of applications. Porous organic polymers (POPs) offer novel properties such as permanent porosity, adjustable chemical nature, and noteworthy thermal and chemical stability. These remarkable properties of the POPs make them promising candidates for use in gas separation and storage. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major cause of global warming. Finding an efficient separation and/or storage material is essential for creating a cleaner environment. Therefore, the importance of the POPs in the field is undeniable. Along these pursuits, several porous polymers have been synthesized with different specifications. The first class of porous polymers are called Covalent Organic Frameworks (COFs). They possess highly ordered structures with very high surface areas and contain light elements. COFs based on B-O, C-N, and B-N bonds have been reported so far. In particular, COFs based on B-O bond formation are well investigated due to the kinetically labile nature of this bond which is essential for overcoming the crystallization problem of covalent networks. Along this line, triptycene-derived covalent organic framework (TDCOF-5) has been synthesized through a condensation reaction between 1, 4-benzenediboronic acid and hexahydroxytriptycene which leads to the formation of boronate ester linkage. TDCOF-5 has the highest H2 uptake under 1 atm at 77K (1.6%) among all known 2D and 3D COFs derived from B–O bond formation and moderate CO2 uptake (2.1 mmol g-1) with Qst values of 6.6 kJ mol-1 and 21.8 kJ mol-1, respectively. The second class of porous structures discussed herein is diazaborole linked polymers (DBLPs). They are constructed based on B-N bond formation and possess amorphous structures due to the lack of the reversible bond formation processes. At this scope, 2, 3, 6, 7, 14, 15-hexaaminotriptycene (HATT) hexahydrocloride was synthesized and reacted with different boronic acid derivatives to produce three different porous polymers under condensation reaction conditions. DBLP-3, -4 and -5 have very high surface areas; 730, 904, and 986 m2 g-1, and offer high CO2 uptake (158.5, 198, and 171.5 mg g-1) at 1 bar and 273 K, respectively. DBLPs have much higher CO2 uptake capacity when compared to almost all reported B-N and B-O containing porous polymers in the field. In addition to high CO2 capacity, DBLPs showed remarkable CO2/N2 and CO2/CH4 selectivity, when the Henry`s law of initial slope selectivity calculations were applied. In general, DBILPs exhibit high selectivities for CO2/N2 (35-51) and CO2/CH4 (5-6) at 298 K which are comparable to those of most porous polymers.

For many applications of industrial relevance, solids providing enhanced porosity such as activated carbons or zeolites have been the key drivers of progress in the past century. Albeit these materials marked an entire era of research, scientists have contributed immense effort to mimic porosity in an artificial way. A rich field to address this challenge is polymer chemistry. Especially covalent triazine frameworks (CTFs), which are exclusively built up from organic matter connected by covalent bonds, have proliferated in the last 10 years and provide remarkable chemical and thermal stability. Within this thesis, a salt templating method for the synthesis of mesoporous CTF materials was developed that applies binary salt mixtures of ZnCl2 (the conventional reaction medium) in combination with alkali halides. In contrast to existing synthetic concepts that induce mesoporosity via high temperature treatment (up to 700 °C), salt templating was conducted at moderate temperatures (300 – 450 °C) and significantly avoided carbonisation as well as nitrogen loss. By applying this new method, salt templated materials with a four-fold increased total pore volume (CTF 1_LiCl: 2.1 cm3 g-1 vs. conventional CTF-1: 0.5 cm3 g-1) and an almost complete retention of the specific surface area (1320 m2 g-1 vs. 1440 m2 g-1) could be synthesised. Another aspect of this thesis dealt with a novel approach to generate CTF materials in a solvent-free, time-efficient and scalable manner. To this end, a mechanochemical synthesis route was developed that makes use of the Friedel-Crafts alkylation to generate CTF materials from cyanuric chloride, serving as triazine node, and electron-rich aromatic compounds as linker molecules. By this method, permanently porous materials (up to 570 m2 g-1) could be synthesised from various monomers with different length and geometry. The syntheses could be conducted within two hours and on a gram scale, thus significantly exceeding known methods in terms of time-efficiency and scalability. Besides these synthetic concepts, three other chapters covered the area of potential applications for CTF materials. To this end, novel CTF materials were synthesised and assessed towards their suitability for use in energy storage systems such as lithium sulfur battery or supercapacitor. In analogy to SPAN, a sulfur containing conductive poly(acrylonitrile) polymer, CTFs containing covalently bound sulfur (S@CTF) were anticipated as promising cathode material in the lithium sulphur battery. Following the synthesis of a variety of different materials, a particular focus was set on determining the impact of sulfur attachment on the porosity and on illustrating the bonding situation of sulfur within the porous host matrix. Elemental analysis revealed that the highest sulfur loadings (33 w%) were obtained for the CTF samples obtained at the lowest synthesis temperature (500 °C). These findings were in agreement with nitrogen adsorption experiments that showed a reduced porosity after sulfur attachment for each material and the largest percental drop of the total pore volume for those samples with the highest sulfur loadings. XPS investigations suggested the presence of C-S species in the sulfur treated materials and supported the formation of covalently bound sulfur. Whereas the synthesis of S@CTF materials was successful, the electrochemical characterisation in a carbonate-based electrolyte revealed a substantial capacity loss after only a few cycles, which was probably due to a loss of active material and underlined that confinement of sulfur might be the key to obtain cathodes with increased cycling stability. In this thesis, a novel pyridine-based CTF material was synthesised, which showed beneficial nitrogen doping and a tuneable porosity by careful choice of the reaction temperature (Scheme 3b). An in-depth characterisation by means of argon physisorption, X-ray photoelectron and Raman spectroscopy was conducted. Thereby, the structural changes upon thermal treatment were carefully investigated and interpreted. The non-purified CTFs – still containing large amounts of ZnCl2 – were directly processed into supercapacitor electrodes. Herein, ZnCl2 was serving two purposes: it acted as a porogen during the CTF synthesis (surface areas up to 3100 m2 g-1 were obtained) and as a precursor for an in situ generated aqueos electrolyte. It was demonstrated that this methodology bypasses extensive washing and more importantly, the findings gained from the electrochemical characterisation matched the structural indications from the XPS experiments. Thus, without purifying the material in advance, this method allowed for estimating the materials’ properties based on its behaviour as supercapacitor. In the last part, a purely CTF-based organocatalyst that benefits from a monomer bearing a catalytically active functionality was synthesised by introducing a charged cationic imidazolium moiety into a microporous covalent triazine framework. A finely adjusted synthetic protocol enabled the structural retention of the thermally labile imidazolium motif, whose successful integration was proven by an in-depth structural characterisation, applying solid-state 1H MAS NMR, XPS and FT-IR spectroscopy. If applied as heterogeneous organocatalyst, the imidazolium-based CTF was active in the carbene-catalysed Umpolung reaction, thus providing clear evidence of an intact structure.

This research presents a new approach to creating large, complex molecules to carry out molecular recognition and catalytic functions mimicking biological proteins. Development of new therapeutics that bind protein surfaces and disrupt protein-protein interactions was first addressed targeting the envelope transmembrane protein in HIV-1, gp41. In this work, spiroligomer inhibitors of gp41 were designed and synthesized, and then the biochemical activity was tested. Rationally designed inhibitors were developed using computational modeling with the Molecular Operating Environment software (MOE). To build the desired molecular shape according to the design, C-2 alkylation of a bis-amino acid monomer was investigated to synthesize the higher degree of bis-amino acids with various reaction conditions for access to all possible diastereomers. Based on this design and synthetic methodology, a spiroligomer targeting gp41 was built by synthesizing each monomer and then linking them together by diketopiperazine (DKP). For the biological evaluation, the gp41-5 gene was transformed into E. coli and the protein was expressed, purified, and refolded for an in vitro binding test. A direct binding, fluorescence polarization assay was used to evaluate the binding affinity of the functionalized spiroligomer to the gp41-5 protein. Its antiviral activity was assessed in collaboration with the Chaiken lab at Drexel University. In addition, investigation into how the unique structures provided by the spiroligomer backbone allow for various uses, such as functionalized struts in porous organic polymers (POPs). In the large internal space of a POP, a nucleophilic, catalytic spiroligomer was installed to increase the reaction rate for the hydrolysis of methyl paraoxon (a neurotoxin G agent stimulant). Spiroligomers were designed and synthesized with backbone DMAP moieties, and the activity of these catalysts was analyzed in collaboration with the Hupp lab at Northwestern University. / Chemistry

Porous organic polymers containing nitrogen-rich building units are among the most promising materials for selective CO2 capture and separation applications that impact the environment and the quality of methane and hydrogen fuels. The work described herein describes post-synthesis modification of Nanoporous Organic Frameworks (NPOFs) and its impact on gas storage and selective CO2 capture. The synthesis of NPOF-4 was accomplished via a catalysed cyclotrimerization reaction of 1,3,5,7-tetrakis(4-acetylphenyl)adamantane in Ethanol/Xylenes mixture using SiCl4 as a catalyst. NPOF-4 is microporous and has high surface area (SABET = 1249 m2 g-1). Post-synthesis modification of NPOF-4 by nitration afforded (NPOF-4-NO2) and subsequent reduction resulted in an amine-functionalized framework (NPOF-4-NH2) that exhibits improved gas storage capacities and high CO2/N2 (139) and CO2/CH4 (15) selectivities compared to NPOF-4 under ambient conditions. These results demonstrate the impact of nitro- and amine- pore decoration on the function of porous organic materials in gas storage and separation application.

Porous organic polymers (POPs) with high physicochemical stability have attracted significant attention from the scientific community as promising platforms for small gas separation adsorbents. Although POPs have amorphous morphology in general, with the help of organic chemistry toolbox, ultrahigh surface area materials can be synthesized. In particular, nitrogen-rich POPs have been studied intensively due to their enhanced framework-CO2 interactions. Postsynthetic modification (PSM) of POPs has been instrumental for incorporating different functional groups into the pores of POPs which would increase the CO2 capture properties. We have shown that functionalizing the surface of POPs with nitro and amine groups increases the CO/N2 and CO2/CH4 selectivity significantly due to selective polarization of CO2 molecule. In addition, controlled postsynthetic nitration of NPOF-1, a nanoporous organic framework constructed by nickel(0)-catalyzed Yamamoto coupling of 1,3,5-tris(4-bromophenyl)benzene, has been performed and is proven to be a promising route to introduce nitro groups and to convert mesopores to micropores without compromising surface area. Reduction of the nitro groups yields aniline-like amine-functionalized NPOF-1-NH2. Adequate basicity of the amine functionalities leads to modest isosteric heats of adsorption for CO2, which allow for high regenerability. The unique combination of high surface area, microporous structure, and amine-functionalized pore walls enables NPOF-1-NH2 to have remarkable CO2 working capacity values for removal from landfill gas and flue gas. Benzimidazole-linked polymers have also been shown to have promising CO2 capture properties. Here, an amine functionalized benzimidazole-linked polymer (BILP-6-NH2) was synthesized via a combination of pre- and postsynthetic modification techniques in two steps. Experimental studies confirm enhanced CO2 uptake in BILP-6-NH2 compared to BILP-6, and DFT calculations were used to understand the interaction modes of CO2 with BILP-6-NH2. Using BILP-6-NH2, higher CO2 uptake and CO2/CH4 selectivity was achieved compared to BILP-6 showing that this material has a very promising working capacity and sorbent selection parameter for landfill gas separation under VSA settings. Additionally, the sorbent evaluation criteria of different classes of organic polymers have been compared in order to reveal structure-property relationships in those materials as solid CO2 adsorbents.