Copper coordination polymers from cavitand ligands: hierarchical spaces from cage and capsule motifs, and other topologies

The cyclotriveratrylene-type ligands (±)-tris(iso-nicotinoyl)cyclotriguaiacylene L1 (±)-tris(4-pyridylmethyl)cyclotriguaiacylene L2 and (±)-tris{4-(4-pyridyl)benzyl}cyclotriguaiacylene L3 all feature 4-pyridyl donor groups and all form coordination polymers with CuI and/or CuII cations that show a remarkable range of framework topologies and structures. Complex [CuI4CuII1.5(L1)3(CN)6]·CN·n(DMF) 1 features a novel 3,4-connected framework of cyano-linked hexagonal metallo-cages. In complexes [Cu3(L2)4(H2O)3]·6(OTf)·n(DMSO) 2 and [Cu2(L3)2Br2(H2O)(DMSO)]·2Br·n(DMSO) 3 capsule-like metallo-cryptophane motifs are formed which linked through their metal vertices into a hexagonal 2D network of (43.123)(42.122) topology or a coordination chain. Complex [Cu2(L1)2(OTf)2(NMP)2(H2O)2]·2(OTf)·2NMP 4 has an interpenetrating 2D 3,4-connected framework of (4.62.8)(62.8)(4.62.82) topology with tubular channels. Complex [Cu(L1)(NCMe)]·BF4·2(CH3CN)·H2O 5 features a 2D network of 63 topology while the CuII analogue [Cu2(L1)2(NMP)(H2O)]·4BF4·12NMP·1.5H2O 6 has an interpenetrating (10,3)-b type structure and complex [Cu2(L2)2Br3(DMSO)]·Br·n(DMSO) 7 has a 2D network of 4.82 topology. Strategies for formation of coordination polymers with hierarchical spaces emerge in this work and complex 2 is shown to absorb fullerene-C60 through soaking the crystals in a toluene solution

Metabolic profiling reveals coordinated switches in primary carbohydrate metabolism in grape berry (Vitis vinifera L.), a non-climacteric fleshy fruit

Changes in carbohydrate metabolism during grape berry development play a central role in shaping the final composition of the fruit. The present work aimed to identify metabolic switches during grape development and to provide insights into the timing of developmental regulation of carbohydrate metabolism. Metabolites from central carbon metabolism were measured using high-pressure anion-exchange chromatography coupled to tandem mass spectrometry and enzymatic assays during the development of grape berries from either field-grown vines or fruiting cuttings grown in the greenhouse. Principal component analysis readily discriminated the various stages of berry development, with similar trajectories for field-grown and greenhouse samples. This showed that each stage of fruit development had a characteristic metabolic profile and provided compelling evidence that the fruit-bearing cuttings are a useful model system to investigate regulation of central carbon metabolism in grape berry. The metabolites measured showed tight coordination within their respective pathways, clustering into sugars and sugar-phosphate metabolism, glycolysis, and the tricarboxylic acid cycle. In addition, there was a pronounced shift in metabolism around veraison, characterized by rapidly increasing sugar levels and decreasing organic acids. In contrast, glycolytic intermediates and sugar phosphates declined before veraison but remained fairly stable post-veraison. In summary, these detailed and comprehensive metabolite analyses revealed the timing of important switches in primary carbohydrate metabolism, which could be related to transcriptional and developmental changes within the berry to achieve an integrated understanding of grape berry development. The results are discussed in a meta-analysis comparing metabolic changes in climacteric versus non-climacteric fleshy fruits

Linear and macrocyclic water soluble polyacylhydrazones and their utilisation in coatings

© 2018 Elsevier B.V. Water soluble polyacylhydrazones have been generated that contain a high proportion of renewable materials. The polyacylhydrazones were found to be present simultaneously as linear and macrocyclic species, the latter being favoured at higher concentrations and in certain combinations of levulinoyl ester/acyldihydrazide. Levulinoyl esters with multiple ketone reactive sites were targeted as building blocks for the backbone. Reaction of these species in aqueous media with commercially available acyldihydrazides afforded a series of high solids-content water soluble polyacylhydrazone solutions. Evaporation of the water from the solutions reproducibly generated films with differing and useful characteristics. One of the polyhydrazones was successfully formulated into two different types of resin bases of commercial coating systems, producing paint products with renewable content

Study of 3,3\u27 vs. 4,4\u27 DDS Isomer Curatives on Physical Properties and Phenyl Ring Motions of DGEBA Epoxy via Molecular Dynamics, Deuterium NMR, and Dielectric Spectroscopy

The purpose of this research is to develop a multiscale understanding of crosslinked amorphous matrices, connecting molecular level events to macroscopic properties. To accomplish this goal, our methodology was to identify network architectures that influence molecular level energy dissipation through mechanisms such as bond rotations, torsions, and ring flips and then relate those molecular motions to macroscopic properties. Studies were accomplished on two aerospace grade matrices: the epoxy, diglycidyl ether of bisphenol A (DGEBA) cured with two amines, 3,3’- diaminodiphenyl sulfone (33DDS) and 4,4’-diaminodiphenyl sulfone (44DDS). The 33DDS/DGEBA and 44DDS/DGEBA served both to provide a baseline for experimental testing of aerospace matrices and to enable the comparison of a meta-substituted vs. parasubstituted diamine in chemically isotropic systems. The results presented in the first seven chapters of the dissertation focus on these two matrices. Molecular Dynamics (MD) simulations provide a tool to quickly create networks with alterations in network architectures, such as crosslink density, aromaticity, sulfone content, pendant bulky groups, etc. MD can then be used to predict thermomechanical properties of these matrices and determine the effect of network architecture on properties. In this work, molecular dynamics simulations were used to accurately predict thermomechanical properties of 33DDS/DGEBA and 44DDS/DGEBA. Additionally, modifications to these baseline matrices were made in order to study the effect of network architecture and chemical composition of matrices. To bridge the gap in understanding between network architecture and ultimate matrix performance, molecular motions resulting from the network architecture and responsible for ultimate properties, must be understood. To analyze these molecular motions, various solid state Nuclear Magnetic Resonance (NMR) spectroscopic techniques, Dielectric Spectroscopy (DES), and Dynamic Mechanical Analysis (DMA) are employed. Deuterium (2H) NMR spin-lattice relaxation studies and lineshape analyses are powerful tools in determining the motional behavior of targeted chemical moieties within the glassy state. Solid state deuterium NMR studies were used to selectively study the phenyl ring motions of 33DDS, 44DDS, and DGEBA in 33DDS/DGEBA and 44DDS/DGEBA networks. Phenyl ring deuterated diglycidyl ether of bisphenol A (d8- DGEBA), 3,3’-diaminodiphenyl sulfone (d8-33DDS), and 4,4’-diaminodiphenyl sulfone (d8-44DDS) were all synthesized. Deuterated DGEBA was reacted with non-deuterated 33DDS and 44DDS to study the effect of the amine on the motions of the epoxy rings. Deuterated 33DDS and 44DDS were reacted with non-deuterated DGEBA to study the phenyl ring motions of the amines. Carbon NMR spectroscopy was also used to provide additional information about phenyl ring motions of the epoxies. While solid state NMR techniques can be used to elucidate the motions of specific chemistries and architectures within the network, secondary, or sub-Tg, relaxations seen in dielectric spectroscopy and dynamic mechanical analysis are often associated with mechanical properties, including modulus, toughness, and strength. The association of the chemistries responsible for specific motions and the contributions of these motions to secondary relaxations help connect the molecular scale to the macroscale. In this work, phenyl ring motions have been correlated with sub-Tg transitions observed with DES and DMA, furthering understanding of the relationship between chemical composition and mechanical properties in polymers. DES and DMA have also shown distinct differences in 33DDS/DGEBA and 44DDS/DGEBA. Solid state NMR techniques were used to study the kinetics of reaction of 33DDS and 44DDS with DGEBA. The reaction of most primary amines before reaction of secondary amines was observed in 33DDS/DGEBA and 44DDS/DGEBA. This provides information on network architecture by showing that DDS/DGEBA systems form linear oligomers prior to crosslinking. The effect of modification with an octafunctional polyhedral oligomeric silsesquioxane (POSS) on network properties of on an ambient cure epoxy was studied. The results show that POSS modification provides substantial increases in mechanical properties at ambient conditions and elevated temperatures. Finally, the surface chemistry of industrially manufactured aerospace composites was analyzed to gain insight on preparing proper surfaces for bonding. Release agents used in the fabrication process were found in trace quantities on the surfaces. The presence of low surface energy release agents on surfaces is counterproductive to the bonding of those surfaces

Polyisobutylene Telechelic Prepolymers by In Situ End-Quenching and Post-Polymerization Modifications

This volume focuses on the development of telechelic polyisobutylene (PIB) prepolymers by combining end-capping of living carbocationic polymerization of isobutylene (IB) with suitable reactants and post-polymerization modifications. Alkylation kinetics of PIB tert-chloride with alkoxybenzenes using either TiCl4 or AlCl3 were investigated. Quantitative para-position end-capped products were only achieved if the alkoxybenzene/AlCl3 molar ratio was greater than unity; while no such molar ratio is required for TiCl4, but the alkylation rate was slower than AlCl3 under the same conditions. Photopolymerization kinetics analysis of PIB triphenol tri(meth)acrylates with low and high Mns, and control aliphatic PIB triol triacrylate with similar high Mn showed that Darocur 1173 afforded the highest photopolymerization rate and conversion. Kinetics analysis also indicated despite of end-funtionality and acrylate structure, photopolymerization rate for PIB prepolymers with high Mns, attributed to reduced diffusional mobility, resulting in decreased rate of termination and autoacceleration. Structure-property relationships indicated the Tg of PIB networks decreased as the Mn of PIB macromer increased regardless of end-group type, and thermal stability remained constant regardless of end-group type. Tensile properties were characteristic of weak rubbery networks. Quantitative synthesis of PIB telechelic prepolymers with various types of epoxides, including aliphatic and phenyl glycidol ether, exo-olefin epoxide, and cyclohexene epoxide have been developed through post modifications. A novel method for PIB chain end functionalization was developed whereby living PIB is end-capped with the bulky comonomer, 4-(4-allyloxyphenyl)-2-methyl-1-butene (AMB) at full IB conversion. Addition is readily limited to one or two comonomer units per chain end at a low [AMB]/[chain end] ratio. The mechanism suggested that upon addition of AMB, the resulting carbocation tends to undergo terminative chain transfer consisting of alkylation of the 4-allyloxyphenyl ring at C2, via a five-membered cyclic intermediate. Grubbs 3rd generation mediated ROMP of PIB (oxa)norbornene macromonomers via a grafting “through” methodology were conducted successfully, producing PIB bottlebrush polymers with controlled molecular weight and low dispersities. Both 1H NMR and SEC kinetics analyses showed pseudo first-order kinetic behavior for these macromonomers. Besides, both kinetic studies demonstrated that the ROMP propagation rate of PIB norbornene is at least 2.2 times greater than that of PIB oxanorborne macromonomer