Showing papers on "Double bond published in 2017"

Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

Abstract: Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals in cross-coupling area is expanding the scope of the coupling partners. In the past decade, diazo compounds (or their precursors N-tosylhydrazones) have emerged as nucleophilic cross-coupling partners in C–C single bond or C═C double bond formations in transition-metal-catalyzed reactions. This type of coupling reaction involves the following general steps. First, the organometallic species is generated by various processes, including oxidative addition, transmetalation, cyclization, C–C bond cleavage, and C–H bond activation. Subsequently, the organometallic species reacts with the diazo substrate to generate metal carbene intermediate, which undergoes rapid migratory insertion to form a C–C bond. The new organometallic species generated from migratory insertion may undergo various transformations. This type of carbene-based coupling has proven...

Selectivity of C–H Activation and Competition between C–H and C–F Bond Activation at Fluorocarbons

Abstract: Partially fluorinated alkanes, arenes, and alkenes can be transformed by a variety of transition metal and lanthanide systems. Although the C–H bond is weaker than the C–F bond regardless of the hybridization of the carbon, the reaction of the C–F bond at the metal is usually more exothermic than the corresponding reaction of the C–H bonds. Both bonds are activated by the metal systems, but the preference for activating these bonds depends on the nature of the hydrocarbon and of the metal system, so that the reaction can be directed exclusively toward C–H or C–F bonds or yield a mixture of products. Additionally, the presence of fluorine differentiates between C–H bonds at different positions resulting in regioselective C–H bond activation; paradoxically, the strongest C–H bond reacts preferentially. The purpose of this review is to describe the field of reactions of partially fluorinated substrates with transition metal atoms, ions, and molecular complexes. The controlling physical properties (thermodyna...

Near-infrared photoswitching of azobenzenes under physiological conditions

Abstract: Biological tissue exhibits an absorbance minimum in the near-infrared between 700 and 900 nm that permits deep penetration of light. Molecules that undergo photoisomerization in this bio-optical window are highly desirable as core structures for the development of photopharmaceuticals and as components of chemical-biological tools. We report the systematic design, synthesis, and testing of an azobenzene derivative tailored to undergo single-photon photoswitching with near-infrared light under physiological conditions. A fused dioxane ring and a methoxy substituent were used to place oxygen atoms in all four ortho positions, as well as two meta positions, relative to the azobenzene N═N double bond. This substitution pattern, together with a para pyrrolidine group, raises the pKa of the molecule so that it is protonated at physiological pH and absorbs at wavelengths >700 nm. This azobenzene derivative, termed DOM-azo, is stable for months in neutral aqueous solutions, undergoes trans-to-cis photoswitching w...

Pinpointing Double Bond and sn-Positions in Glycerophospholipids via Hybrid 193 nm Ultraviolet Photodissociation (UVPD) Mass Spectrometry

Abstract: Complete structural characterization of complex lipids, such as glycerophospholipids, by tandem mass spectrometry (MS/MS) continues to present a major challenge. Conventional activation methods do not generate fragmentation patterns that permit the simultaneous discernment of isomers which differ in both the positions of acyl chains on the glycerol backbone and the double bonds within the acyl chains. Herein we describe a hybrid collisional activation/UVPD workflow that yields near-complete structural information for glycerophospholipids. This hybrid MS3 strategy affords the lipid’s sum composition based on the accurate mass measured for the intact lipid as well as highly specific diagnostic product ions that reveal both the acyl chain assignment (i.e., sn-position) and the site-specific location of double bonds in the acyl chains. This approach is demonstrated to differentiate sn-positional and double-bond-positional isomers, such as the regioisomeric phosphatidylcholines PC 16:0/18:1(n-9) and PC 18:1(n-...

Oxidative 1,2-carboamination of alkenes with alkyl nitriles and amines toward γ-amino alkyl nitriles.

Abstract: Difunctionalization of alkenes has become a powerful tool for quickly increasing molecular complexity in synthesis. Despite significant progress in the area of alkene difunctionalization involving the incorporation of a nitrogen atom across the C–C double bonds, approaches for the direct 1,2-carboamination of alkenes to produce linear N-containing molecules are scarce and remain a formidable challenge. Here we describe a radical-mediated oxidative intermolecular 1,2-alkylamination of alkenes with alkyl nitriles and amines involving C(sp3)–H oxidative functionalization catalysed by a combination of Ag2CO3 with iron Lewis acids. This three-component alkene 1,2-alkylamination method is initiated by the C(sp3)–H oxidative radical functionalization, which enables one-step formation of two new chemical bonds, a C–C bond and a C–N bond, to selectively produce γ-amino alkyl nitriles. Difunctionalization of readily available alkenes is a powerful method to quickly build molecular complexity. Here the authors report a three-component, oxidative carboamination between alkenes, alkyl nitriles and amines, producingγ-amino alkyl nitriles.

Manganese(I)-Catalyzed Regio- and Stereoselective 1,2-Diheteroarylation of Allenes: Combination of C−H Activation and Smiles Rearrangement

Abstract: Heteroarenes are important structural motif in functional molecules. Reported herein is a Mn(I)-catalyzed 1,2-diheteroarylation of allenes via a C-H activation/Smiles rearrangement cascade. The reaction occurred under additive-free or even solvent-free conditions which allowed the creation of two C-C and one C-N bonds in a single operation. A series of structurally diverse bicyclic or tricyclic compounds bearing an exocyclic double bond were constructed in good to excellent efficiency. The decarboxylative ring-opening of the products led to the facile synthesis of vicinal biheteroaryls. Synthetic applications were demonstrated and preliminary mechanistic studies were conducted.

A Stable Neutral Compound with an Aluminum-Aluminum Double Bond.

Abstract: Homodinuclear multiple-bonded neutral Al compounds, aluminum analogues of alkenes, have been a notoriously difficult synthetic target over the past several decades. Herein, we report the isolation of a stable neutral compound featuring an Al═Al double bond stabilized by N-heterocyclic carbenes. X-ray crystallographic and spectroscopic analyses demonstrate that the dialuminum entity possesses trans-planar geometry and an Al–Al bond length of 2.3943(16) A, which is the shortest distance reported for a molecular dialuminum species. This new species reacts with ethylene and phenyl acetylene to give the [2+2] cycloaddition products. The structure and bonding were also investigated by detailed density functional theory calculations. These results clearly demonstrate the presence of an Al═Al double bond in this molecule.

Copper-Catalyzed Three-Component Carboazidation of Alkenes with Acetonitrile and Sodium Azide.

Abstract: A copper-catalyzed three-component reaction of alkenes, acetonitrile, and sodium azide afforded γ-azido alkyl nitriles by formation of one C(sp3 )-C(sp3 ) bond and one C(sp3 )-N bond. The transformation allows concomitant introduction of two highly versatile groups (CN and N3 ) across the double bond. A sequence involving the copper-mediated generation of a cyanomethyl radical and its subsequent addition to an alkene, and a C(sp3 )-N bond formation accounted for the reaction outcome. The resulting γ-azido alkyl nitrile can be easily converted into 1,4-diamines, γ-amino nitriles, γ-azido esters, and γ-lactams of significant synthetic value.

Structural Characterization of Phosphatidylcholines Using 193 nm Ultraviolet Photodissociation Mass Spectrometry

Abstract: Advances in mass spectrometry have made it a preferred tool for structural characterization of glycerophospholipids. Collisional activation methods commonly implemented on commercial instruments do not provide fragmentation patterns that allow elucidation of certain structural features, including acyl chain positions on the glycerol backbone and double bond positions within acyl chains. In the present work, 193 nm ultraviolet photodissociation (UVPD) implemented on an Orbitrap mass spectrometer is used to localize double bond positions within phosphatidylcholine (PC) acyl chains. Cleavage of the carbon–carbon bonds adjacent to the double bond provides a diagnostic mass difference of 24 Da and enables differentiation of double-bond positional isomers. The UVPD method was extended to the characterization of PCs in a bovine liver extract via a shotgun strategy. Positive mode higher energy collisional dissociation (HCD) and UVPD, and negative mode HCD were undertaken in a complementary manner to identify spec...

Organotin(IV) complexes derived from proteinogenic amino acid: synthesis, structure and evaluation of larvicidal efficacy on Anopheles stephensi mosquito larvae

Abstract: Five new organotin(IV) complexes of composition [Bz2SnL1]n (), [Bz3SnL1H⋅H2O] (), [Me2SnL2⋅H2O] (), [Me2SnL3] () and [Bz3SnL3H]n () (where L1 = (2S)-2-{[(E)-(4-hydroxypentan-2-ylidene)]amino}-4-methylpentanoate, L2 = (rac)-2-{[(E)-1-(2-hydroxyphenyl)methylidene]amino}-4-methylpentanoate and L3 = (2S)- or (rac)-2-{[(E)-1-(2-hydroxyphenyl)ethylidene]amino}-4-methylpentanoate) were synthesized and characterized using 1H NMR, 13C NMR, 119Sn NMR and infrared spectroscopic techniques. The crystal structure of reveals a distorted trigonal-bipyramidal geometry around the tin atom where the oxygen atoms of the carboxylate ligand and a water ligand occupy the axial positions, while the three benzyl ligands are located at the equatorial positions. On the other hand, the analogous derivative of enantiopure L3H () consists of polymeric chains, in which the ligand-bridged tin atoms adopt the same trans-Bz3SnO2 trigonal-bipyramidal configuration and are now coordinated to a phenolic oxygen atom instead of H2O. In , the OH hydrogen of the ketoimine substituent has moved to the nearby nitrogen atom while in the salicylidene derivative , the OH is located almost midway between the phenolic oxygen atom and the nitrogen atom of the C[DOUBLE BOND]N group. For the dibenzyltin derivative , a polymeric chain structure is observed as a result of a long intermolecular Sn⋅⋅⋅O bond involving the exocyclic carbonyl oxygen atom from the tridentate ligand of a neighbouring tin-complex unit. The tin atom in this complex has distorted octahedral coordination geometry. In contrast, the racemic dimethyltin(IV) complexes and display discrete monomeric structures with a distorted octahedral- and trigonal-bipyramidal geometry, respectively. The structures show that the coordination mode of the Schiff base ligand depends primarily on the number of bulky benzyl ligands (R) at the tin atom, as indeed found in the structures of related complexes where R = phenyl. With three bulky R groups, the tridentate chelating O,N,O coordination mode is preferred, whereas with fewer or less bulky R ligands, only the carboxylate and hydroxy groups are involved, which leads to polymers. Larvicidal efficacies of two of the new tribenzyltin(IV) complexes ( and ) were assessed on the second larval instar of Anopheles stephensi mosquito larvae and compared with two triphenyltin(IV) analogues, [Ph3SnL1H]n and [Ph3SnL3H]n. The results demonstrate that the compounds containing Sn–Ph ligands are more effective than those with Sn–Bz ligands. Copyright © 2016 John Wiley & Sons, Ltd.

Cool white, persistent room-temperature phosphorescence in carbon dots embedded in a silica gel matrix

Abstract: Herein we report the observation of room-temperature phosphorescence from carbon dots (CDs) embedded in a silica gel matrix The precursors used in the synthesis (malonic acid and ethylene diamine) were chosen to have the surface of the CDs rich in C[double bond, length as m-dash]O and C[double bond, length as m-dash]N functionalities The CDs in an aqueous dispersion exhibit an intense blue fluorescence and upon incorporation into silica gel demonstrate a green after-glow, which is visible even to the naked eye The phosphorescence measurements indicated that the life-time of phosphorescence emission is about 18 s, under 380 nm excitation, which is the highest magnitude reported for CDs in solid-state matrices Moreover, the 1931 CIE color parameters corresponding to the phosphorescence emission are in the white gamut region of the chromaticity diagram

Catalytic Carbon-Chlorine Bond Activation by Selenium-Based Chalcogen Bond Donors.

Abstract: Chalcogen bonding is a noncovalent interaction based on electrophilic chalcogen substituents, which shares many similarities with the more well-known hydrogen and halogen bonding. Herein, the first application of selenium-based chalcogen bond donors in organocatalysis is described. Cationic bifunctionalized organoselenium compounds activate the carbon-chlorine bond of 1-chloroisochroman in a benchmark reaction. While imidazolium-based derivatives showed no noticeable activation, benzimidazolium backbones yielded potent catalysts. In all cases, syn-isomers were markedly more active, presumably due to bidentate coordination, which was confirmed by DFT calculations. Comparison experiments with the corresponding non-selenated as well as the non-cationic reference compounds clearly indicate that the catalytic activity can be ascribed to chalcogen bonding. The rate acceleration by the catalyst-compared to the non-selenated derivative-was about 10 fold.

Catalytic Enantioselective Hetero-dimerization of Acrylates and 1,3-Dienes

Abstract: 1,3-Dienes are ubiquitous and easily synthesized starting materials for organic synthesis, and alkyl acrylates are among the most abundant and cheapest feedstock carbon sources. A practical, highly enantioselective union of these two readily available precursors giving valuable, enantio-pure skipped 1,4-diene esters (with two configurationally defined double bonds) is reported. The process uses commercially available cobalt salts and chiral ligands. As illustrated by the use of 20 different substrates, including 17 prochiral 1,3-dienes and 3 acrylates, this hetero-dimerization reaction is tolerant of a number of common organic functional groups (e.g., aromatic substituents, halides, isolated mono- and di-substituted double bonds, esters, silyl ethers, and silyl enol ethers). The novel results including ligand, counterion, and solvent effects uncovered during the course of these investigations show a unique role of a possible cationic Co(I) intermediate in these reactions. The rational evolution of a mecha...

Singlet oxygen-mediated selective C-H bond hydroperoxidation of ethereal hydrocarbons.

Abstract: Singlet O2 is a key reactive oxygen species responsible for photodynamic therapy and is generally recognized to be chemically reactive towards C=C double bonds. Herein, we report the hydroperoxidation/lactonization of α-ethereal C–H bonds by singlet O2 (1Δg) under exceptionally mild conditions, i.e., room temperature and ambient pressure, with modest to high yields (38~90%) and excellent site selectivity. Singlet O2 has been known for > 90 years, but was never reported to be able to react with weakly activated C–H bonds in saturated hydrocarbons. Theoretical calculations indicate that singlet O2 directly inserts into the α-ethereal C–H bond in one step with conservation of steric configuration in products. The current discovery of chemical reaction of singlet oxygen with weakly activated solvent C–H bonds, in addition to physical relaxation pathway, provides an important clue to a 35-year-old unresolved mystery regarding huge variations of solvent dependent lifetime of singlet O2. Singlet oxygen is known to react with carbon–carbon double bonds. Here, the authors show the unusual functionalization of α-ethereal C–H bonds mediated by singlet oxygen under mild conditions to afford lactones and hydroperoxide products.

Control of Selectivity through Synergy between Catalysts, Silanes, and Reaction Conditions in Cobalt-Catalyzed Hydrosilylation of Dienes and Terminal Alkenes

Abstract: Readily accessible (i-PrPDI)CoCl2 [i-PrPDI = 2,6-bis(2,6-diisopropylphenyliminoethyl)pyridine] reacts with 2 equiv of NaEt3BH at −78 °C in toluene to generate a catalyst that effects highly selective anti-Markovnikov hydrosilylation of the terminal double bond in 1,3- and 1,4-dienes. Primary and secondary silanes such as PhSiH3, Ph2SiH2, and PhSi(Me)H2 react with a broad spectrum of terminal dienes without affecting the configuration of the other double bond. When dienes conjugated to an aromatic ring are involved, both Markovnikov and anti-Markovnikov products are formed. The reaction is tolerant of various functional groups such as an aryl bromide, aryl iodide, protected alcohol, and even a silyl enol ether. Reactions of 1-alkene under similar conditions cleanly lead to a mixture of Markovnikov and anti-Markovnikov hydrosilylation products, where the ratio of the products increasingly favors the latter, as the size of the 2,6-substituents in the iminoylaryl group becomes larger. The complex (i-PrPDI)CoC...

Enantioselective Synthesis of (E)-δ-Boryl-Substituted anti-Homoallylic Alcohols Using Palladium and a Chiral Phosphoric Acid

Abstract: (E)-δ-Boryl-substituted anti-homoallylic alcohols are synthesized in a highly diastereo- and enantioselective manner from 1,1-di(boryl)alk-3-enes and aldehydes. Mechanistically, the reaction consists of 1) palladium-catalyzed double-bond transposition of the 1,1-di(boryl)alk-3-enes to 1,1-di(boryl)alk-2-enes, 2) chiral phosphoric acid catalyzed allylation of aldehydes, and 3) palladium-catalyzed geometrical isomerization from the Z to E isomer. As a result, the configurations of two chiral centers and one double bond are all controlled with high selectivity in a single reaction vessel.

Alkene–Carbene Isomerization induced by Borane: Access to an Asymmetrical Diborene

Abstract: A 2,3-dihydro-1H-1,2-azaborole derivative 2 was converted to a cyclic (alkyl) (amino)carbene (cAAC) via 1,2-hydrogen migration triggered by boranes to afford cAAC-borane adducts. This procedure allowed us to develop an asymmetrical diborene cAAC·(Br)B═B(Br)·IDip 6, which was isolated and fully characterized. The 11B NMR spectrum, X-ray diffraction analysis and computational studies indicate that π-electrons on the central B2 moiety in 6 are unequivalently distributed, and thus polarized. A complete scission of the B═B double bond in 6 was achieved by the treatment with an isonitrile, which led to the formation of a base-stabilized B,N-containing methylenecyclopropane 7.

Determination of Double Bond Positions in Polyunsaturated Fatty Acids Using the Photochemical Paternò-Büchi Reaction with Acetone and Tandem Mass Spectrometry.

Abstract: The positions of double bonds along the carbon chain of methylene interrupted polyunsaturated fatty acids are unique identifiers of specific fatty acids derived from biochemical reactions that occur in cells. It is possible to obtain direct structural information as to these double bond positions using tandem mass spectrometry after collisional activation of the carboxylate anions of an acetone adduct at each of the double bond positions formed by the photochemical Paterno-Buchi reaction with acetone. This reaction can be carried out by exposing a small portion of an inline fused silica capillary to UV photons from a mercury vapor lamp as the sample is infused into the electrospray ion source of a mass spectrometer. Collisional activation of [M – H]− yields a series of reverse Paterno-Buchi reaction product ions that essentially are derived from cleavage of the original carbon–carbon double bonds that yield an isopropenyl carboxylate anion corresponding to each double bond location. Aldehydic reverse Pate...

Interfacial Clustering-Triggered Fluorescence-Phosphorescence Dual Solvoluminescence of Metal Nanoclusters

Abstract: The fluorescence–phosphorescence dual solvoluminescence (SL) of water-soluble metal nanoclusters (NCs) at room temperature was successfully achieved by a simple solvent-stimulated strategy. The strong interaction between carboxylate ligands and the metal core at the nanoscale interface not only induces rigid conformations of carbonyl groups but also affords a perfect carbonyl cluster that acts as an exact chromophore of metal NCs for aggregation-induced emission (AIE) mechanics. The clustering of carbonyl groups bearing on the polymer backbone chain is promoted by newly discovered n → π* noncovalent interactions. The efficient delocalization of electrons in overlapped C═O double bonds between neighboring carbonyl groups triggered by strong n → π* interactions in the polymer cluster accounts for its unique SL properties, especially the abnormal phosphorescence. This was further confirmed by controlled experiments for the presence of intersystem crossing (ISC) transitions. The results provide novel insights...

Dehydrogenative desaturation-relay via formation of multicenter-stabilized radical intermediates.

Abstract: In organic molecules, the reactivity at the carbon atom next to the functional group is dramatically different from that at other carbon atoms. Herein, we report that a versatile copper-catalyzed method enables successive dehydrogenation or dehydrogenation of ketones, aldehydes, alcohols, α,β-unsaturated diesters, and N-heterocycles to furnish stereodefined conjugated dienecarbonyls, polyenecarbonyls, and nitrogen-containing heteroarenes. On the basis of mechanistic studies, the copper-catalyzed successive dehydrogenation process proceeds via the initial α,β-desaturation followed by further dehydrogenative desaturation of the resultant enone intermediate, demonstrating that the reactivity at α-carbon is transferred through carbon-carbon double bond or longer π-system to the carbon atoms at the positions γ, e, and η to carbonyl groups. The dehydrogenative desaturation-relay is ascribed to the formation of an unusual radical intermediate stabilized by 5- or 7,- or 9-center π-systems. The discovery of successive dehydrogenation may open the door to functionalizations of the positions distant from functional groups in organic molecules.

Twist of a Silicon–Silicon Double Bond: Selective Anti-Addition of Hydrogen to an Iminodisilene

Abstract: Hydrogenation of alkenes with C═C bonds is a ubiquitous reaction in organic chemistry. However, this transformation remains unknown for heavier counterparts, disilenes with Si═Si bonds. Here we report the isolation of (Z)-diiminodisilyldisilene 2 featuring a highly trans-bent and twisted structure and the longest silicon–silicon double bond reported to date. In silico studies suggested that the Si═Si bond in 2 is described as very weak double donor–acceptor bond. We utilized the remarkable electronic and structural features of this product to achieve the first demonstration of hydrogen activation by a multiply bonded silicon compound under ambient conditions. Interestingly, NMR and X-ray analysis gave exclusively racemic (RR/SS)-1,2-disilane 3a, indicating a stereospecific trans-hydrogenation of the Si═Si bond. In-depth calculations revealed that in strong contrast to the reactivity of C═C bonds, a concerted anti-addition pathway was favored due to the twisted structure of 2.

Theoretical kinetics analysis for Ḣ atom addition to 1,3-Butadiene and related reactions on the Ċ4H7 potential energy surface

Abstract: The oxidation chemistry of the simplest conjugated hydrocarbon, 1,3-butadiene, can provide a first step in understanding the role of polyunsaturated hydrocarbons in combustion and, in particular, an understanding of their contribution toward soot formation. On the basis of our previous work on propene and the butene isomers (1-, 2-, and isobutene), it was found that the reaction kinetics of Ḣ-atom addition to the C═C double bond plays a significant role in fuel consumption kinetics and influences the predictions of high-temperature ignition delay times, product species concentrations, and flame speed measurements. In this study, the rate constants and thermodynamic properties for Ḣ-atom addition to 1,3-butadiene and related reactions on the Ċ4H7 potential energy surface have been calculated using two different series of quantum chemical methods and two different kinetic codes. Excellent agreement is obtained between the two different kinetics codes. The calculated results including zero-point energies, si...

Formal Allylic C(sp3)–H Bond Activation of Alkenes Triggered by a Sodium Amide

Abstract: The catalytic use of a sodium amide has been exploited for formal allylic C(sp3)–H bond activation of alkenes under mild conditions. Subsequent C–C bond formations with imines have proceeded in high yields with complete regioselectivity and excellent geometric selectivity. Aromatic cyano, chloro, and bromo functionalities are tolerated by the transition metal-free catalyst. Complex amines bearing a C═C double bond and distinct heteroaromatic units have been prepared in a single step. The critical importance of sodium versus other s-, p-, d-, and f-block metals as well as metal-free systems has been revealed. In addition, two catalytically active sodium-based intermediates were detected by NMR and HRMS analyses.

NHC-Stabilised Acetylene-How Far Can the Analogy Be Pushed?

Abstract: Experimental studies suggest that the compound (NHCbz )2 C2 H2 can be considered as a complex of a distorted acetylene fragment which is stabilised by benzoannelated N-heterocyclic carbene ligands (NHCbz )→(C2 H2 )←(NHCbz ). A quantum chemical analysis of the electronic structures shows that the description with dative bonds is more favourable than with electron-sharing double bonds (NHCbz )=(C2 H2 )=(NHCbz ).

Insertion of double bond π-bridges of A–D–A acceptors for high performance near-infrared polymer solar cells

Abstract: Double bond π-bridges were introduced into an A–D–A structured n-type organic semiconductor (n-OS) IDT-IC and a new n-OS acceptor SJ-IC was synthesized. In comparison with IDT-IC, the SJ-IC film shows significantly red-shifted absorption, improved electron mobility and tuned crystallinity, which make its blend film with a polymer donor easier to form appropriate phase separation. The polymer solar cells with polymer J61 as a donor and SJ-IC as an acceptor demonstrated a higher PCE of 9.27% with a higher Jsc of 16.99 mA cm−2, while the device based on J61/IDT-IC only delivered a PCE of 6.95% with a Jsc of 13.70 mA cm−2, which should be ascribed to the red-shifted and broadened absorption of SJ-IC. Therefore, inserting double bond π-bridges into n-OS acceptor molecules is a simple and effective way to broaden and red-shift their absorption to improve their photovoltaic performance. In addition, the near-infrared absorption of the SJ-IC acceptor should be beneficial to its future application in semitransparent and tandem PSCs.