Complementary Chemistry Research Articles

Accelerating the Curing of Hybrid Poly(Hydroxy Urethane)-Epoxy Adhesives by the Thiol-Epoxy Chemistry.

The polyaddition between dicyclic carbonates and diamines leading to poly(hydroxy urethane)s (PHUs) has emerged as the preferred method for the synthesis of green, non-isocyanate polyurethanes. However, when proposed for use as structural adhesives, the long times for completion of aminolysis of the 5-membered cyclic carbonates under ambient conditions force the use of complementary chemistries to accelerate the curing process. In this work, a system that combines an amino-terminated PHU (NH2-PHU-NH2), an epoxy resin, and a thiol compound was employed to develop high-shear strength PHU-epoxy hybrid adhesives able to cure at room temperature in short times. A NH2-PHU-NH2 prepolymer synthesized by using a sub-stoichiometric quantity of dicyclic carbonates was mixed with a bisphenol A-based epoxy resin for the preparation of the structural adhesive. While this adhesive showed good lap-shear strength and shear resistance under static load and temperature, the curing process was slow. In order to speed up the curing process, a thiol (trimethylolpropane tris(3-mercapto propionate)) was added and its impact on the curing process as well as on the adhesive properties was evaluated. The trifunctional thiol additive allowed for faster curing in the presence of the 1,1,3,3-tetramethylguanidine basic catalyst. Moreover, a combination of NH2-PHU-NH2 and the thiol as curing agents for the epoxy resin resulted in adhesives with superior toughness, without any deterioration of the ultimate lap-shear strength or shear resistance under load and temperature, making these adhesives suitable for high-demand applications in the automotive industry.

Synthesis and Characterization of Novel Isosorbide‐Based Polyester Derivatives Decorated with α‐Acyloxy Amides

Multicomponent Reactions The power of M2: In article number 2100497 Hatice Mutlu and co-workers, by fusing two powerful complementary chemistries, Metathesis and Multicomponent reactions, novel polyester derivatives decorated with α-acyloxy amides and isosorbide moieties are synthesized in a straightforward fashion. Crucially, the potential utility of isosorbide as a building block for polymers with prospective biomedical application (namely, as novel cartilage materials) is illustrated.

Unveiling the Complementary Manganese and Oxygen Redox Chemistry for Stabilizing the Sodium‐Ion Storage Behaviors of Layered Oxide Cathodes

AbstractLayered oxide cathodes for sodium‐ion batteries (SIBs) have drawn increasing attention owing to their fascinating additional capacity contributed by oxygen‐redox chemistry. Unfortunately, excessive oxygen redox incurs an irreversible oxygen release, deteriorating the cyclic stability and compromising the advantage of additional capacity. Significant efforts have been made so far to stabilize lattice oxygen, but the potential advantages associated with oxygen loss have been ignored. Herein, a complementary Mn and O redox mechanism is first revealed in a novel P2‐Na0.75Ca0.04[Li0.1Ni0.2Mn0.67]O2 cathode. The partial oxygen release activates more Mn3+/Mn4+ redox capacities upon cycling, which effectively compensate the capacity loss from O2‐/On‐ redox and thus enable an ultra‐stable cycling performance (capacity retentions of 102.1% and 95.2% over 100 and 200 cycles at 5 C, respectively). The fast Na+ diffusion kinetics of the cathode also ensure an exceptional rate capability (133.1 and 68.8 mAh g‐1 at 0.1 and 20 C, respectively). The electrode crystal/electronic structure evolution and charge compensation mechanism upon sodiation/desodiation have been elucidated via systematic operando measurements and theoretical computations. The complementary chemistry is a universal principle that stabilizes the Na‐storage behaviors of Mn‐based oxide cathodes, providing new opportunities for anionic redox to boost the energy density and cycling life of SIBs simultaneously.

Synthesis of Enantiopure Sulfoxides by Concurrent Photocatalytic Oxidation and Biocatalytic Reduction.

The concurrent operation of chemical and biocatalytic reactions in one pot is still a challenging task, and, in particular for chemical photocatalysts, examples besides simple cofactor recycling systems are rare. However, especially due to the complementary chemistry that the two fields of catalysis promote, their combination in one pot has the potential to unlock intriguing, unprecedented overall reactivities. Herein we demonstrate a concurrent biocatalytic reduction and photocatalytic oxidation process. Specifically, the enantioselective biocatalytic sulfoxide reduction using (S)-selective methionine sulfoxide reductases was coupled to an unselective light-dependent sulfoxidation. Protochlorophyllide was established as a new green photocatalyst for the sulfoxidation. Overall, a cyclic deracemization process to produce nonracemic sulfoxides was achieved and the target compounds were obtained with excellent conversions (up to 91 %) and superb optical purity (>99 % ee).

Chemoadaptive Polymeric Assemblies by Integrated Chemical Feedback in Self-Assembled Synthetic Protocells.

The design and chemical synthesis of artificial material objects which can mimic the functions of living cells is an important ongoing scientific endeavor. A key challenge necessary for fulfilling the criteria for a system to be living currently regards evolution, which is derived from adaptivity. Integrated chemical loops capable of feedback control are required to achieve chemical systems which exhibit adaptivity. To explore this, we present an integrated, two-component orthogonal chemical process involving reversible addition–fragmentation chain transfer (RAFT) based polymerization-induced self-assembly (PISA) and a copper-catalyzed azide–alkyne click (CuAAC) coupling reaction. The chemical processes are linked through electron transfer from the activated chain-transfer agent (CTA) to the dormant Cu(II) precatalyst. We show that combining these complementary chemistries in a single reaction pot resulted in two primary outcomes: (i) simplification of the PISA process to synthesize the macro-CTA in situ from available nonamphiphilic components and (ii) routes to complexity and adaptation involving population dynamics, morphologies, and dissipative phenomena observed during in situ microscopy analysis.

Role of Multivalent Interactions in Dynamic-Template-Directed Assembly of Conjugated Polymers

Dynamic-template-directed assembly is a promising method to enhance molecular ordering and electronic properties of solution-coated polymer semiconductor thin films over large area. In this work, we establish that multicomponent dynamic templates of complimentary chemistries can promote polymer crystallization through cooperative multivalent interactions. We investigate this phenomenon using a combination of templating substrates including a fluoropolymer, a hydrogen-bonded liquid and an ionic liquid. Template-dependent multiscale morphology is studied by a comprehensive set of characterization techniques to understand how introducing diverse chemical moieties modulates polymer assembly. Our results clearly confirm synergistic effect between components of complimentary chemistries constituting the dynamic template. The relative degree of crystallinity is improved by 50-150% for films deposited on multicomponent dynamic templates compared to their neat constituents. In addition, macroscopic alignment is increased significantly (2 to 5 times) compared to single-component templates. As a result, highly anisotropic charge transport is observed with apparent hole mobilities up to 3.6 cm2V-1s-1. In contrast, such synergistic effect is not observed when using multicomponent dynamic template of comparable chemistries (i.e. ionic liquid and polymerized ionic liquid). We elucidate the origin of this synergistic effect through a combination of attenuated total reflectance Fourier transform infrared spectroscopy and isothermal titration calorimetry. When the dynamic template is comprised of two or more components interacting with complementary binding sites on the conjugated polymer (esp. backbone vs. side chain), the template-polymer interactions is significantly enhanced compared to the sum of single component contributions. These results provide valuable insights on surface-directed conjugated polymer crystallization during large-area solution coating. Template dynamics is rarely studied, and represents a new opportunity for guiding assembly of soft functional matter.

Preparation of Stable Branched DNA Nanostructures: Process of Cooperative Self-Assembly.

The construction of functionalizable branched DNA (bDNA) relies on the designing of oligonucleotides and exploitation of their complementary chemistries. The stability of these structures largely depends on the hybridization specificity of the contributing oligonucleotides. However, most of the bDNA structures are not found suitable for in vivo application due to poor yield owing to uncharacterized hybridization efficiency and instability in biological fluids. In this report, our group has explored a mechanistic way for studying the hybridization pathway of genomic sequence derived oligonucleotides that are self-assembled to fabricate robust bDNA structures. The effect of change in nucleotide sequences on bDNA stability was studied by taking oligonucleotides derived from primers of different genes. Additionally, the stability of the bDNA in solutions with different pH, salts, and DNaseI which mimics physiological environment was reported. It was found that genomic sequence derived oligonucleotides self-assembled in a cooperative manner to yield the designed bDNAs, which are stable in physiological environment.

Cross-dehydrogenative coupling and oxidative-amination reactions of ethers and alcohols with aromatics and heteroaromatics.

Cross-dehydrogenative coupling (CDC) is a process in which, typically, a C-C bond is formed at the expense of two C-H bonds, either catalyzed by metals or other organic compounds, or via uncatalyzed processes. In this perspective, we present various modes of C-H bond-activation at sp3 centers adjacent to ether oxygen atoms, followed by C-C bond formation with aromatic systems as well as with heteroaromatic systems. C-N bond-formation with NH-containing heteroaromatics, leading to hemiaminal ethers, is also an event that can occur analogously to C-C bond formation, but at the expense of C-H and N-H bonds. A large variety of hemiaminal ether-forming reactions have recently appeared in the literature and this perspective also includes this complementary chemistry. In addition, the participation of C-H bonds in alcohols in such processes is also described. Facile access to a wide range of compounds can be attained through these processes, rendering such reactions useful for synthetic applications via Csp3 bond activations.

High-Performance Concrete Incorporating Locally Available Industrial By-Products

AbstractThis paper presents the concept of industrial symbiosis in which four industries available locally (steel plant, thermal power plant, aluminum plant, and stone quarry) are connected with the concrete industry. By-products generated by these industries (slag, fly ash, red mud, and quarry dust) were activated with a small amount of clinker to form four concrete mixes. The heat of hydration and the autogenous shrinkage were monitored on the fresh concrete mixes. The chloride migration and electrical resistivity of the concrete were measured at different concrete ages over 91 days. Drying shrinkage was monitored for 56 days, and compressive strength was tested after 28 and 91 days. The concrete prepared with a high volume of fly ash, slag, red mud, and quarry dust had very low chloride migration coefficients and less drying shrinkage compared to concrete prepared with ordinary cement. The synergetic beneficial effect of these by-products is explained by their complementary chemistry and particle-size ...

A Unified Reduced Model for Auto-Ignition and Combustion in Premixed Systems

In this paper, two complementary chemistry model reduction methods for combustion simulations are further developed and combined. A progress variable model (PVM), which follows the idea of trajectory generated manifolds (TGLDM), is tailored for describing auto-ignition in situations where the influence of<br />molecular transport on chemical reaction is weak, like auto-ignition in media with weak scalar gradients. The other model using the reaction diffusion manifold approach (REDIM) is designed for situations where the interaction of chemistry with molecular transport is essential. The formulation of both models is discussed and implementational issues of each single model are given. Also, each model is tested in its respective range of applicability (quasi-homogeneous combustion under steady/unsteady physical boundary conditions for the PVM, combustion in fields with essential scalar gradients for REDIM). The coupling of the two models into a unified model, which covers combustion in both regimes and during the transitions between regimes, is discussed, based on the global quasi-linearization concept (GQL).

ChemInform Abstract: α‐Isocupreine, an Enantiocomplementary Catalyst of β‐Isocupreidine.

Complementary chemistry! α-Isocupreine (-ICPN) was synthesized for the first time in one step from quinine by treatment with CF3SO3H (see scheme). This compound serves as an enantiocomplementary catalyst to β-isocupreidine (β-ICD) in the Morita–Baylis–Hillman reaction.

α‐Isocupreine, an Enantiocomplementary Catalyst of β‐Isocupreidine

Complementary chemistry! α-Isocupreine (-ICPN) was synthesized for the first time in one step from quinine by treatment with CF3SO3H (see scheme). This compound serves as an enantiocomplementary catalyst to β-isocupreidine (β-ICD) in the Morita–Baylis–Hillman reaction.

Engineering Cell Surfaces via Liposome Fusion

In this study, we have rewired cell surfaces with ketone and oxyamine molecules based on liposome fusion for applications in cell-surface engineering. Lipid vesicles, functionalized with ketone and oxyamine molecules, display complementary chemistry and undergo recognition, docking, and subsequent fusion upon covalent oxime bond formation. Liposome fusion was characterized by several techniques including matrix-assisted laser-desorption/ionization mass spectrometry (MALDI-MS), light scattering, fluorescence resonance energy transfer (FRET), and transmission electron microscopy (TEM). When cultured with cells, ketone- and oxyamine-containing liposomes undergo spontaneous membrane fusion to present the respective molecules from cell surfaces. Ketone-functionalized cell surfaces serve as sites for chemoselective ligation with oxyamine-conjugated molecules. We tailored and fluorescently labeled cell surfaces with an oxyamine-conjugated rhodamine dye. As an application of this cell-surface engineering strategy, ketone- and oxyamine-functionalized cells were patterned on oxyamine- and ketone-presenting surfaces, respectively. Cells adhered, spread, and proliferated in the patterned regions via interfacial oxime linkage. The number of ketone molecules on the cell surface was also quantified by flow cytometry.

Programmable Chemical Gradient Patterns by Soft Grayscale Lithography

A method for fabricating chemical gradients on planar and nonplanar substrates using grayscale lithography is reported. Compliant grayscale amplitude masks are fabricated using a vacuum-assisted microfluidic filling protocol that employs dilutions of a carbon-black-containing polydimethylsiloxane emulsion (bPDMS) within traditional clear PDMS (cPDMS) to create planar, fully self-supporting mask elements. The mask is then placed over a surface functionalized with a hydrophobic coumarin-based photocleavable monolayer, which exposes a polar group upon irradiation. The mask serves to modulate the intensity of incident UV light, thereby controlling the density of molecules cleaved. The resulting molecular-level grayscale patterns are characterized by condensation microscopy and imaging mode time-of-flight secondary-ion mass spectrometry (ToF-SIMS). Due to the inherent flexibility of this technique, the photofuse as well as the gradient patterns can be designed for a wide range of applications; in this paper two proof-of-concept demonstrations are shown. The first utilizes the ability to control the resulting contact angle of the surface for the fabrication of a passive pressure-sensitive microfluidic gating system. The second is a model surface modification process that utilizes the functional groups deprotected during the photocleavage to pattern the deposition of moieties with complementary chemistry. The spatial layout, resolution, and concentration of these covalently linked molecules follow the gradient pattern created by the grayscale mask during exposure. The programmable chemical gradient fabrication scheme presented in this work allows explicit engineering of both surface properties that dictate nonspecific interactions (surface energy, charge, etc.) and functional chemistry necessary for covalent bonding.

α-Synuclein and ALPS motifs are membrane curvature sensors whose contrasting chemistry mediates selective vesicle binding

Membrane curvature sensors have diverse structures and chemistries, suggesting that they might have the intrinsic capacity to discriminate between different types of vesicles in cells. In this paper, we compare the in vitro and in vivo membrane-binding properties of two curvature sensors that form very different amphipathic helices: the amphipathic lipid-packing sensor (ALPS) motif of a Golgi vesicle tether and the synaptic vesicle protein α-synuclein, a causative agent of Parkinson's disease. We demonstrate the mechanism by which α-synuclein senses membrane curvature. Unlike ALPS motifs, α-synuclein has a poorly developed hydrophobic face, and this feature explains its dual sensitivity to negatively charged lipids and to membrane curvature. When expressed in yeast cells, these two curvature sensors were targeted to different classes of vesicles, those of the early secretory pathway for ALPS motifs and to negatively charged endocytic/post-Golgi vesicles in the case of α-synuclein. Through structures with complementary chemistries, α-synuclein and ALPS motifs target distinct vesicles in cells by direct interaction with different lipid environments.

Synthesis of a Hemoglobin Polymer Containing Antioxidant Enzymes Using Complementary Chemistry of Maleimides and Sulfhydryls

To increase the overall size of hemoglobin (Hb), we developed a novel system of polymerization based on the complementary chemistry between sulfhydryls and maleimides. The maleimides were introduced onto the protein through N-(-maleimidobutyryloxy) succinimide, while the sulfhydryls were added using 2-iminothiolane hydrochloride (Trauts reagent). Resulting polymers showed SDS-PAGE bands with molecular weights as high as 96 kDa. Size exclusion chromatography has demonstrated species with molecular weight > 700 kDa. The flexibility of the sulfhydryl-maleimide chemistry has also allowed insertion of two antioxidant enzymes, catalase (Cat) and superoxide dismutase (SOD), into the Hb polymer. Cat was incorporated into the heavier fractions of the polymer, while SOD was found throughout the molecular weight range.

On the origin of microrhythmic layering in arfvedsonite lujavrite from the Ilímaussaq alkaline complex, South Greenland

Microrhythmic layering is locally developed in agpaitic arfvedsonite lujavrite from the Ilímaussaq alkaline complex, South Greenland. Three–15-cm-thick laminated dark layers alternate with 1–10-cm-thick, light-coloured granular urtitic layers. Dark layers are uniform (isomodal) but the urtitic layers are enriched in early nepheline and eudialyte in their lower parts and in late analcime and REE phosphate minerals in the upper parts. The layers are separated by sharp contacts; they are draped around rafts from the overlying roof zone and lack structures indicative of current processes or post-cumulus deformation. Compared with the background arfvedsonite lujavrite of the complex, the dark layers are richer in sodalite, microcline and arfvedsonite and poorer in analcime and eudialyte. They have higher K 2O, Cl, FeO ⁎ and S but lower Na 2O, H 2O +, Zr and P contents, the opposite of the light-coloured layers. The complementary chemistry of the two types of layers oscillates about the composition of the background arfvedsonite lujavrite. Layers probably formed in a stagnant bottom layer of the lujavrite magma chamber. Each layer started as a liquid layer which exchanged components with the underlying crystallization front. On cooling, it crystallized primocrysts and exchanged components with the overlying magma which became a new, complementary liquid layer and, during further cooling and burial within the sequence of layers, it underwent largely closed-system interstitial crystallization. Exhaustion of Cl and a sharp decrease in a NaCl relative to a H 2O terminated the crystallization of a sodalite-rich dark layer and initiated abundant crystallization of nepheline in the overlying liquid layer (urtitic layer). The layered sequence represents a local K 2O-, Cl-rich but Na 2O-, H 2O-poor facies of arfvedsonite lujavrite and may have formed by exchanging components with sodalite-bearing rafts from the roof zone.

Assembly of Binary Colloidal Structures via Specific Biological Adhesion

We present a novel approach to the fabrication of binary colloidal materials where specific biomolecular cross-linking drives the self-assembly of bidisperse colloidal suspensions. In particular, we have employed low-affinity immune system carbohydrate-selectin interactions to mediate the heterotypic assembly of binary colloidal structures. Using small (0.94 μm) and larger (5.5 μm) diameter particles coated with complementary chemistry, we show that a progressive series of structures, such as colloidal micelles (a large particle coated with smaller particles), colloidal clusters, rings, and elongated chains, can be made by decreasing the number fraction, NA/NB, of small (A) to large (B) particles (200 ≥ NA/NB ≥ 2) at low total volume fraction (φΤ = 10-4−10-3). The assembly is due to specific molecular interactions, as control experiments in which the molecules are blocked or eliminated do not lead to the assembly of these structures. The size of the structures can be modulated by time or total volume frac...

Efficient Synthesis of Light-Harvesting Arrays Composed of Eight Porphyrins and One Phthalocyanine

Effective light-harvesting arrays require multiple photoactive energy donors that funnel energy to an energy acceptor. Porphyrins and phthalocyanines are attractive components for light-harvesting arrays due to their strong absorption in the blue and red regions, respectively, and because energy transfer can occur from porphyrin to phthalocyanine regardless of their respective metalation states. Star-shaped light-harvesting arrays comprised of eight peripheral porphyrins and one core phthalocyanine have been prepared by a streamlined synthesis involving minimal reliance on protecting groups, a high degree of convergence, and facile chromatographic purification. The synthesis involves three distinct stages of complementary chemistries (porphyrin formation, Pd-mediated porphyrin dimer formation, phthalocyanine formation). Statistical reaction of p-iodobenzaldehyde, a phthalonitrile-linked benzaldehyde, and 5-mesityldipyrromethane afforded the desired trans-iodo/phthalonitrile-substituted porphyrin, which un...

From Oligonucleotides to Phospholipids: Cross-Fertilization Through Complementary Chemistry

From Oligonucleotides to Phospholipids: Cross-Fertilization Through Complementary Chemistry