Covalent Bonds Research Articles

Supramolecular Assembly Frameworks(SAFs): Shaping the Future of Functional Materials

Supramolecular assembly frameworks (SAFs) represent a new category of porous materials, utilizing non‐covalent interactions, setting them apart from metal‐organic frameworks (MOFs) and covalent organic frameworks (COFs). This category includes but is not restricted to hydrogen‐bonded organic frameworks and supramolecular organic frameworks. SAFs stand out for their outstanding porosity, crystallinity, and stability, alongside unique dissolution‐recrystallization dynamics that enable significant structural and functional modifications. Crucially, their non‐covalent assembly strategies allow for a balanced manipulation of porosity, symmetry, crystallinity, and dimensions, facilitating the creation of advanced crystalline porous materials unattainable through conventional covalent or coordination bond synthesis. Despite their considerable promise in overcoming several limitations inherent to MOFs and COFs, particularly in terms of solution‐processability, SAFs have received relatively little attention in recent literature. This Minireview aims to shed light on standout SAFs, exploring their design principles, synthesis strategies, and characterization methods. It emphasizes their distinctive features and the broad spectrum of potential applications across various domains, aiming to catalyze further development and practical application within the scientific community.

Polyurethane combining preeminent toughness, puncture-resistance, and self-healing capabilities by multiple repair options based on dual dynamic covalent bonds

The development of self-healing materials has enabled the production of more reliable and intelligent materials. However, resolving the conflict between mechanical strength and self-healing efficiency as well as limited repair options of the self-healing materials is still the most pressing scientific challenge. In this study, a self-healing polyurethane with multiple repair methods is prepared by introducing disulfide bonds into thermo-reversible imine bonds-based polyurethane. The resultant polyurethane exhibits impressive comprehensive mechanical properties and preeminent repair capabilities. More importantly, damages can be repaired through various routes such as room temperature, moderate temperature, hair dryer blowing, and ethylenediamine assistance treatments. The superior mechanical properties, repetitive self-healing performance, and multiple options for repair is attributed to the cooperation of thermally reversible imine and disulfide exchanges, thermal motion of molecular chains, and dissociation/regeneration of hydrogen bonds. So this research provides numerous ideal options for repairing cracks and other damages in materials used in construction industry under different usage environments. Consequently, high-quality repairs, improved efficiency, and extended service life of construction engineering materials can be ensured.

An innovative ionic liquid-aqueous biphasic system for simultaneously highly efficient dechroming and collagen recovery from chrome-tanned leather shavings at room temperature

Chrome-tanned leather shavings (CTLS) with abundant collagen of 70–90 wt% but high Cr content of 2–4 wt% are considered as hazardous wastes. Due to the stable covalent bond between Cr and collagen, current processes for collagen recovery from CTLS face challenges including low dechroming efficiency, collagen disruption, high energy and chemical consumption and secondary pollution. In this paper, an innovative IL-targeted homogeneous isolation (IL-THI) process based on the reusable ionic liquid-aqueous biphasic system (IL-ABS) was established for the simultaneous resource recovery and complete dechroming of CTLS at room temperature, with the recovery rate of collagen reached 72.4 % while Cr content in collagen is reduced from 35.65 × 103 mg/kg to 1.78 mg/kg. This IL-ABS enriched TBAH in the upper phase and potassium tartrate in the lower phase. Moreover, TBAH demonstrated excellent reproducibility across five cycles, achieving consistently low Cr content of 2.65 mg/kg in collagen, far below the 50 mg/kg limit in national standards. The triple helix conformation and the molecular weight of the collagen product were confirmed via Fourier-transform infrared spectroscopy, X-ray diffraction analyses, circular dichroism spectra analysis and SDS-PAGE. Moreover, economic calculations demonstrated the suitability of this novel process for sustainable CTLS recovery. The superior dechroming ability of IL-ABS is attributed to the formation of Cr(III)-Tartrate complexes, which preferentially migrate to the lower phase due to the solvophobic effect, while dissolved collagen is recovered from the upper phase, as disclosed by UV–Vis spectra, ICP-OES, and all-atom molecular dynamics simulations. Additionally, IL-THI process demonstrates considerable potential for the isolation of Cr(III) and collagen in solid waste, with low energy consumption, improved separation efficiency, and increased design flexibility.

DFT-D3 and TD-DFT Studies of the Adsorption and Sensing Behavior of Mn-Phthalocyanine toward NH3, PH3, and AsH3 Molecules.

This study employs density functional theory (DFT) calculations at the B3LYP/6-311+g(d,p) level to investigate the interaction of XH3 gases (X = N, P, As) with the Mn-phthalocyanine molecule (MnPc). Grimme's D3 dispersion correction is applied to consider long-range interactions. The adsorption behavior is explored under the influence of an external static electric field (EF) ranging from -0.514 to 0.514 V/Å. Chemical adsorption of XH3 molecules onto the MnPc molecule is confirmed. The adsorption results in a significant decrease in the energy gap (Eg) of MnPc, indicating the potential alteration of its optical properties. Quantum theory of atoms in molecules (QTAIM) analysis reveals partially covalent bonds between XH3 and MnPc, and the charge density differenc (Δρ) calculations suggest a charge donation-back donation mechanism. The UV-vis spectrum of MnPc experiences a blue shift upon XH3 adsorption, highlighting MnPc's potential as a naked-eye sensor for XH3 molecules. Thermodynamic calculations indicate exothermic interactions, with NH3/MnPc being the most stable complex. The stability of NH3/MnPc decreases with increasing temperature. The direction and magnitude of the applied electric field (EF) play a crucial role in determining the adsorption energy (Eads) for XH3/MnPc complexes. The Eg values decrease with an increasing negative EF, which suggests that the electrical conductivity (σ) and the electrical sensitivity (ΔEg) of the XH3/MnPc complexes are influenced by the magnitude and direction of the applied EF. Overall, this study provides valuable insights into the suggested promising prospects for the utilization of MnPc in sensing applications of XH3 gases.

Functionalized γ-Boehmite Covalent Grafting Modified Polyethylene for Lithium-Ion Battery Separator.

In the field of lithium-ion batteries, the challenges posed by the low melting point and inadequate wettability of conventional polyolefin separators have increased the focus on ceramic-coated separators. This study introduces a highly efficient and stable boehmite/polydopamine/polyethylene (AlOOH-PDA-PE) separator. It is crafted by covalently attaching functionalized nanosized boehmite (γ-AlOOH) whiskers onto polyethylene (PE) surfaces. The presence of a covalent bond increases the stability at the interface, while amino groups on the surface of the separator enhance the infiltration of the electrolyte and facilitate the diffusion of lithium ions. The PE-PDA-AlOOH separator, when used in lithium-ion batteries, achieves a discharge capacity of 126 mAh g-1 at 5 C and retains 97.1% capacity after 400 cycles, indicating superior cycling stability due to its covalently bonded ceramic surface. Thus, covalent interface modification is a promising strategy to prevent delamination of ceramic coatings in separators.

Potential Utilization of Loess in Grouting Materials: Effects of Grinding Time and Calcination Temperature

Potential Utilization of Loess in Grouting Materials: Effects of Grinding Time and Calcination Temperature

Emerging and Re-emerging Warheads for Targeted Covalent Inhibitors: An Update.

Covalent inhibitors and other types of covalent modalities have seen a revival in the past two decades, with a variety of new targeted covalent drugs having been approved in recent years. A key feature of such molecules is an intrinsically reactive group, typically a weak electrophile, which enables the irreversible or reversible formation of a covalent bond with a specific amino acid of the target protein. This reactive group, often called the "warhead", is a critical determinant of the ligand's activity, selectivity, and general biological properties. In 2019, we summarized emerging and re-emerging warhead chemistries to target cysteine and other amino acids (Gehringer, M.; Laufer, S. A. J. Med. Chem. 2019, 62, 5673-5724; DOI: 10.1021/acs.jmedchem.8b01153). Since then, the field has rapidly evolved. Here we discuss the progress on covalent warheads made since our last Perspective and their application in medicinal chemistry and chemical biology.

Preparation and tribological properties of porous polyimide modified by graphene

PurposeThe purpose of this article is to prepare graphene/polyimide composite materials for use as bearing cage materials, improving the friction and wear performance of bearing cages.Design/methodology/approachThe oil absorption and discharge tests were conducted to evaluate the oil content properties of the materials, while the mechanical properties were analyzed through cross-sectional morphology examination. Investigation into the tribological behavior and wear mechanisms encompassed characterization and analysis of wear trace morphology in PPI-based materials. Consequently, the influence of varied graphene nanoplatelets (GN) concentrations on the oil content, mechanical and tribological properties of PPI-based materials was elucidated.FindingsThe composites exhibit excellent oil-containing properties due to the increased porosity of PPI-GN composites. The robust formation of covalent bonds between GN and PPI amplifies the adhesive potency of the PPI-GN composites, thereby inducing a substantial enhancement in impact strength. Notably, the PPI-GN composites showed enhanced lubrication properties compared to PPI, which was particularly evident at a GN content of 0.5 Wt.%, as evidenced by the minimization of the average coefficient of friction and the width of the abrasion marks.Practical implicationsThis paper includes implications for elucidating the wear mechanism of the polyimide composites under frictional wear conditions and then to guide the optimization of oil content and tribological properties of polyimide bearing cage materials.Originality/valueIn this paper, homogeneously dispersed PPI-GN composites were effectively synthesized by introducing GN into a polyimide matrix through in situ polymerization, and the lubrication mechanism of the PPI composites was compared with that of the PPI-GN composites to illustrate the composites’ superiority.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2023-0415

Higher-Order Structural Analysis of a Transparent and Flexible High Thermal Conductive Liquid Crystalline Elastomer Sheet and Its Composite.

Transparency, flexibility, and high thermal conductivity are trade-offs. Specifically, we have investigated a cross-linked acrylic liquid crystal elastomer (LCE) that exhibits both transparency and flexibility while maintaining a high level of thermal conductivity. The transparent monodomain LCE sheet was achieved through a process of stretching an initially opaque polydomain sheet to 80% elongation and subsequently subjecting it to photocuring. The thermal conductivity in the stretching direction (x) of the monodomain LCE sheet was found to be 1.8 times higher than that of the prestretched polydomain sheet, consistent with findings from previous studies. However, in the orthogonal direction (y) to the stretching (x) direction, the thermal conductivity exhibited an even higher value, being 1.7 times greater than in the x-direction, with a value of 3.0 W/(m·K). This unique observation prompted us to conduct further investigation through higher-order structural analysis of these LCE sheets using 2D wide-angle X-ray scattering (WAXS) analysis. In the transparent sheet, the LCE molecules were aligned in the sheet in the stretching x-direction (monodomain structure) for the out-of-plane direction. However, in the in-plane x-direction, the molecular plane spacing exhibited random orientation at a period of 0.45 nm. In contrast, within the y-direction of the inner layer, the molecular plane spacing exhibited a uniaxial horizontal orientation at the same period length as in the x-direction. The heat energy entering into the y-direction once spreads to the x-direction, but it was considered that the reason for the higher thermal conductivity to the y-direction would be forming covalent bonds that function as new heat transmission paths, in the direction intersecting to the x-direction during photocuring. Therefore, we concluded that the synergistic effect of the high level of the ordered inner structure and covalent bonding structure due to cross-linking in the y-direction contributes to its higher thermal conductivity compared to that in the x-direction, which exhibits a random in-plane structure. Additionally, we have fabricated an LCE composite sheet filled with 75 vol % of alumina particles using a polydomain-type LCE as the base material. The composite sheet exhibits remarkable thermal conductivity in the thickness direction, measuring at 9.8 W/(m·K), while maintaining a flexibility characterized by an elastic modulus of 70 MPa. This thermal conductivity surpasses that of a nonmesogenic acrylic composite sheet with identical alumina particle filling, which measured at 3.9 W/(m·K), more than twice as much. The presence of the mesogen skeleton has been demonstrated to enhance heat transfer, even within soft composites, by facilitating the formation of an ordered structure.

Sulfite ion and gold (111) surface interaction mechanism

The interaction of a sulfite ion (SO32−) with the Au (111) surface has been studied using density functional theory. The results of the geometry optimization, the charge density distribution, and the density of states showed that sulfite ions exhibit a strong interaction with the Au (111) surface atoms, and they are adsorbed by forming a strong ionic bond that leads to the rearrangement of Au surface atoms. Consequently, this interaction leads to a charge transfer from the sulfite ion to Au surface atoms. The results proved a change in the geometry of the adsorbed sulfite ion, but it is not degraded on the gold surface because of the covalent bonds between sulfur and oxygen atoms.

Oligonucleotide-Based Photoaffinity Probes: Chemical Tools and Applications for Protein Labeling.

A variety of proteins interact with DNA and RNA, including polymerases, histones, ribosomes, transcription factors, and repair enzymes. However, the transient non-covalent nature of these interactions poses challenges for analysis. Introducing a covalent bond between proteins and DNA via photochemical activation of a photosensitive functional group introduced onto nucleic acids offers a means to stabilize these often weak interactions without significantly altering the binding interface. Consequently, photoactivatable oligonucleotides are powerful tools for investigating nucleic acid-protein interactions involved in numerous biological and pathological processes. In this review, we provide a comprehensive overview of the chemical tools developed so far and the different strategies used for incorporating the most commonly used photoreactive reagents into oligonucleotides probes or nucleic acids. Furthermore, we illustrate their application with several examples including protein binding site mapping, identification of protein binding partners, and in cell studies.

Synergistic Outcomes in Drug Delivery: Exploring Harmonious Architectures of Interpenetrating Polymer Networks.

Pharmaceutical excipients play a crucial role in determining the outcome of delivered therapeutic cargo density. By far, polymers have captured the biggest share in the excipients market. This surge in demand motivated researchers to look for newer and novel polymeric platforms. Interpenetrating polymeric networks (IPN) are a class of polymer in the same polymer blend league, where two different polymer chains penetrate; and align with each other without any sustainable covalent bond. The novel agreement between the polymer chains equips the IPN with the characteristic features of each participating polymer unit, thus making IPN superior to its predecessors. IPN has crossed a long path, especially in the pharmaceutical medicine field, from the mere coinage of the term to widespread usage, especially in drug delivery, where they increased the bioavailability and efficacy of the co-delivered drugs. The current review will highlight the major studies that have led to the current face of the IPN in various pharmaceutical domains. The present review was conducted by comprehensively reviewing published reports within the recent period using multiple keywords related to IPN and its role in drug delivery. Moving forward, continued exploration and innovation in IPN technologies promise to further enhance their applications, offering novel solutions for the challenges in drug delivery and therapeutic cargo density.

N-Heterocyclic Carbene Monolayers on Metal-Oxide Films: Correlations between Adsorption Mode and Surface Functionality.

N-Heterocyclic carbene (NHC) ligands have been self-assembled on various metal and semimetal surfaces, creating a covalent bond with surface metal atoms that led to high thermal and chemical stability of the self-assembled monolayer. This study explores the self-assembly of NHCs on metal-oxide films (CuOx, FeOx, and TiOx) and reveals that the properties of these metal-oxide substrates play a pivotal role in dictating the adsorption behavior of NHCs, influencing the decomposition route of the monolayer and its impact on work function values. While the attachment of NHCs onto CuOx is via coordination with surface oxygen atoms, NHCs interact with TiOx through coordination with surface metal atoms and with FeOx via coordination with both metal and oxygen surface atoms. These distinct binding modes arise due to variances in the electronic properties of the metal atoms within the investigated metal-oxide films. Contact angle and ultraviolet photoelectron spectroscopy measurements have shown a significantly higher impact of F-NHC adsorption on CuOx than on TiOx and FeOx , correlated to a preferred, averaged upright orientation of F-NHC on CuOx.

Adaptive and Robust Vitrimers Fabricated by Synergy of Traditional and Supramolecular Polymers

AbstractVitrimers offer a unique combination of mechanical performance, reprocessability, and recyclability that makes them highly promising for a wide range of applications. However, achieving dynamic behavior in vitrimeric materials at their intended usage temperatures, thus combining reprocessability with adaptivity through associative dynamic covalent bonds, represents an attractive but formidable objective. Herein, we couple boron‐nitrogen (B−N) dative bonds and B−O covalent bonds to generate a new class of vitrimers, boron‐nitrogen vitrimers (BNVs), to endow them with dynamic features at usage temperatures. Compared with boron‐ester vitrimers (BEVs) without B−N dative bonds, the BNVs with B−N dative bonds showcase enhanced mechanical performance. The excellent mechanical properties come from the synergistic effect of the dative B−N supramolecular polymer and covalent boron‐ester networks. Moreover, benefiting from the associative exchange of B−O dynamic covalent bonds above their topological freezing temperature (Tv), the resultant BNVs also possess the processability. This study leveraged the structural characteristics of a boron‐based vitrimer to achieve material reinforcement and toughness enhancement, simultaneously providing novel design concepts for the construction of new vitrimeric materials.

Robust mechanical strength and high colorfastness of amorphous photonic crystals on fabrics with durable antibacterial and anti-static properties

The technique of utilizing structural color dyeing presents a sustainable and energy-conserving approach to textile dyeing. However, the coating with structural coloration always exhibited cracks and inadequate colorfastness attributed to the presence of capillary tension. In this study, we employed a hydrophilic silane called 3-aminopropyltriethoxysilane (KH550) to chemically modify the fabric. This method endowed the fabric with reactive amino groups, thereby augmenting the interfacial bonding strength between polydopamine (PDA)@SiO2@Ag+/Ag NPs and the fabric substrate through metal coordination and covalent bonds. Additionally, by utilizing catechol complexation, we successfully loaded Ag ions onto the PDA coating of composite microspheres. These Ag ions acted as linkers during self-assembly of microspheres. The active amino groups on the surface of chemically modified cotton fabric reacted with PDA at a specific temperature, resulting in the formation of robust covalent bonds simultaneously. The resulting fabric demonstrated excellent water resistance as well as efficient antibacterial and anti-static properties, which were confirmed through various mechanical tests such as washing, folding, and rubbing experiments. This research presents an innovative approach for creating durable structural colored fabrics with multifunctional properties based on metal coordination and covalent bonds that can be effectively applied in textile printing and dyeing.

A Spontaneous In Situ Thiol-Ene Crosslinking Hydrogel with Thermo-Responsive Mechanical Properties.

The thermo-responsive behavior of Poly(N-isopropylacrylamide) makes it an ideal candidate to easily embed cells and allows the polymer mixture to be injected. However, P(NiPAAm) hydrogels possess minor mechanical properties. To increase the mechanical properties, a covalent bond is introduced into the P(NIPAAm) network through a biocompatible thiol-ene click-reaction by mixing two polymer solutions. Co-polymers with variable thiol or acrylate groups to thermo-responsive co-monomer ratios, ranging from 1% to 10%, were synthesized. Precise control of the crosslink density allowed customization of the hydrogel's mechanical properties to match different tissue stiffness levels. Increasing the temperature of the hydrogel above its transition temperature of 31 °C induced the formation of additional physical interactions. These additional interactions both further increased the stiffness of the material and impacted its relaxation behavior. The developed optimized hydrogels reach stiffnesses more than ten times higher compared to the state of the art using similar polymers. Furthermore, when adding cells to the precursor polymer solutions, homogeneous thermo-responsive hydrogels with good cell viability were created upon mixing. In future work, the influence of the mechanical micro-environment on the cell's behavior can be studied in vitro in a continuous manner by changing the incubation temperature.

Effect of Epoxy Macromolecules as Interfacial Mediators on the Microstructure and Physical Properties of Styrene Butadiene Rubber/ Talcum Powder Composites

Poly(isoprene-co-glycidyl methacrylate) epoxy macromolecules were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization to act as interfacial mediators between talcum powder (Talc) and styrene-butadiene rubber (SBR) with the aim of improving the properties of SBR/Talc composites. The epoxy macromolecules were uniformly dispersed on the surface of Talc using the spray-drying method. Subsequently, the modified Talc was utilized in the preparation of SBR composites. During hot vulcanization, isoprene double bonds could directly graft onto the rubber skeleton. Simultaneously, the epoxy groups opened the ring and formed covalent bonds with silanol. The interfacial covalent bonds were found to significantly enhance the dispersion of Talc and the interfacial interactions between SBR and Talc, as evidenced by scanning electron microscopy, cross-linking density measurements, and rubber processing analyzer tests. Differential scanning calorimetry results indicated that the number of interfacial covalent bonds and the content of glassy layers in the composites increased with the rise in GMA content and modified Talc. At equivalent filler loadings, epoxy macromolecules with 20 wt% and 34 wt% GMA increased the tensile strength by 31% and 49%, respectively. Concerning viscoelastic properties, composites containing interfacial covalent bonds exhibited superior stress relaxation and stress softening properties.

Electronic and magnetic properties of Mn-doped and Mn-X (F, Cl, Br, I) co-doped modulated monolayer SnSe2

The density functional theory is employed for learning the modulation of the electronic structure and magnetic properties of monolayer SnSe2 by an Mn atom and by co-doping an Mn atom with a halogen atom. It is found that intrinsic SnSe2 is nonmagnetic, which is consistent with the properties of semiconductors. Following Mn atom doping, the doped system is magnetic and the magnetic moments are primarily responsible for the Mn atom. After co-doping the Mn atom with halogen atoms, the doped system's total magnetic moments are decreased. The examination of the electronic structure demonstrates that the doping of the Mn atom and the co-doping of the Mn atom with halogen atoms lead to the introduction of impurity energy levels into the doped system, which appear only in the spin-up part and do not cross the Fermi energy level. There is asymmetry between the spin-up and spin-down energy bands and the doped system exhibits magnetic semiconductor properties. The hybridization of the p-orbitals of the halogen atoms and the 3d orbitals of the Mn atom is primarily responsible for the introduction of impurity energy levels in the energy bands of the doped system. In the Mn-doped system, ionic bonds were shaped between Mn and Se. In the co-doped system, strong ionic bonds were shaped between the Mn atom and F, Cl atoms, and covalent bonds were shaped between the Mn atom and Br, I atoms.

Systematic identification and analysis of immune-related circRNAs of Pelteobagrus fulvidraco involved in Aeromonas veronii infection

Circular RNA (circRNA) represents a type of newly discovered non-coding RNA, distinguished by its closed loop structure formed through covalent bonds. Recent studies have revealed that circRNAs have crucial influences on host anti-pathogen responses. Yellow catfish (Pelteobagrus fulvidraco), an important aquaculture fish with great economic value, is susceptible to Aeromonas veronii, a common aquatic pathogen that can cause acute death. Here, we reported the first systematic investigation of circRNAs in yellow catfish, especially those associated with A. veronii infection at different time points. A total of 1205 circRNAs were identified, which were generated from 875 parental genes. After infection, 47 circRNAs exhibited differential expression patterns (named DEcirs). The parental genes of these DEcirs were functionally engaged in immune-related processes. Accordingly, seven DEcirs (novel_circ_000226, 278, 401, 522, 736, 843, and 975) and six corresponding parental genes (ADAMTS13, HAMP1, ANG3, APOA1, FGB, and RALGPS1) associated with immunity were obtained, and their expression was confirmed by RT-qPCR. Moreover, we found that these DEcir-gene pairs likely acted through pathways, such as platelet activation, antimicrobial humoral response, and regulation of Ral protein signal transduction, to influence host immune defenses. Additionally, integrated analysis showed that, of the 7 immune-related DEcirs, three targeted 16 miRNAs, which intertwined into circRNA-miRNA networks. These findings revealed that circRNAs, by targeting genes or miRNAs are highly involved in anti-bacterial responses in yellow catfish. Our study comprehensively illustrates the roles of circRNAs in yellow catfish immune defenses. The identified DEcirs and the circRNA-miRNA network will contribute to the further investigations on the molecular mechanisms underlying yellow catfish immune responses.

Predictive modeling of novel GaAgX2 (X = S, Se) chalcogenides: First-principles study of electronic, optical, and thermoelectric properties

The most prominent aspects of ternary-type chalcogenides are their tunable optical abilities and outstanding thermoelectric stability. Here the advanced density functional theory is used to examine the complicated interaction of the electronic structure, optical, thermodynamic, and thermoelectric properties of novel GaAgX2 (X = S, Se) chalcogenides. The total energies vs volume of the two materials were computed to formulate ground state characteristics. Both the materials confirmed to have direct band gap nature with an energy gap of 0.8 eV, and 2.2 eV, using TB-mBJ potential, respectively. As compared to GaAgS2, the crystal structure of GaAgSe2 have more covalent bonds that enlarged the covalency and results in wider energy gap of GaAgSe2 as compared to GaAgS2. For the negative value of ε1(ω), these materials display metallic nature, resulting to show a total reflection of the incoming photons. The GaAgS2 displays better absorption than GaAgSe2 materials with higher energy photons. With a few high peaks of refractive index in (2.8–5.5) eV energy range, suggesting these materials appropriate to be used in optical devices. These materials have positive Seebeck coefficients and are confirmed to have a p-type nature. At ambient temperature, GaAgS2 has lower thermal conductivity than GaAgSe2.