Functionalized sp Carbon-Conjugated Covalent Organic Frameworks for Interfacial Modulation of Inverted Perovskite Solar Cells.

Interfacial modulation utilizing functional materials is proven to be crucial for obtaining high photovoltaic performance in lead halide perovskite solar cells (PSCs). This study investigates, for the first time, the utilization of a pyrene-based sp carbon-conjugated covalent organic framework (spc-COF) as an interfacial layer in inverted PSCs. Functionalized with cyano (-CN) Lewis base groups, the spc-COF exhibits a dual effect, simultaneously passivating both the NiO and the perovskite layers.

Solvent-Templated Methylammonium-Based Ruddlesden-Popper Perovskites with Short Interlayer Distances.

Two-dimensional (2D) halide perovskites are exquisite semiconductors with great structural tunability. They can incorporate a rich variety of organic species that not only template their layered structures but also add new functionalities to their optoelectronic characteristics. Here, we present a series of new methylammonium (CHNH or MA)-based 2D Ruddlesden-Popper perovskites templated by dimethyl carbonate (CHOCOOCH or DMC) solvent molecules.

Chelating Phosphine-N-Heterocyclic Carbene Platinum Complexes via Catalytic Asymmetric Hydrophosphination and Their Cytotoxicity Toward MKN74 and MCF7 Cancer Cell Lines.

A series of activated vinyl azoles was hydrophosphinated in the presence of a chiral palladacycle catalyst under mild conditions to give enantioenriched phosphine azoles with moderate enantioselectivities and yields. The racemic phosphine azoles were transformed into eleven novel chelating phosphine-N-heterocyclic carbene (NHC) platinum complexes. The drug efficacies of nine selected phosphine-NHC platinum(II) chlorides in two cancer cell lines (MKN74 and MCF7) were evaluated, and two were found to exhibit activities comparable to that of cisplatin.

C-As Bond Formation Reactions for the Preparation of Organoarsenic(III) Compounds.

Potential widespread applications of organoarsenic chemistry have been limited by the inherent lack of safe and effective As-C bond formation reactions. Several alternative reagents and methods have been developed in the last few decades to address the hazards and drawbacks associated with traditional arsenic synthetic strategies. Herein, this minireview summarizes the advances made in nucleophilic, electrophilic, radical and metal-mediated As(III)-C bond formations while specifically highlighting the behavior of arsenic synthons with various well-established reagents (eg.

Catalytic Asymmetric Diarylphosphine Addition to α-Diazoesters for the Synthesis of P-Stereogenic Phosphinates via P*-N Bond Formation.

The asymmetric catalytic P-H addition of racemic secondary phosphines to electrophilic α-diazoesters via P*-N bond formation is disclosed for the first time. Interaction between the diazoester and the palladium catalyst resulted in the unusually enhanced electrophilic ability of the terminal nitrogen in the diazo functionality, as opposed to the commonly expected formation of a metal carbene by nitrogen elimination. Further derivatization of the generated phosphinic hydrazones provided access to enantioenriched P-stereogenic diarylphosphinates via a simple transformation.

Catalytic Approach toward Chiral P,N-Chelate Complexes Utilizing the Asymmetric Hydrophosphination Protocol.

A synthetic procedure for obtaining a chiral P,N ligand was developed by exploiting the versatility of the asymmetric hydrophosphination protocol catalyzed by a phosphapalladacycle complex. The addition of the synthesized ligand to various metal sources led to the generation of chiral and enantioenriched chelate complexes, which can be useful prototypes for catalyst design in the future. The resulting coordination compounds were comprehensively characterized by solid-state (X-ray crystallography) and solution-based (one- and two-dimensional NMR spectroscopy) techniques and natural bond orbital (density functional theory) analysis to determine their structural and key electronic features.

Triflic-Acid-Catalyzed Tandem Allylic Substitution-Cyclization Reaction of Alcohols with Thiophenols-Facile Access to Polysubstituted Thiochromans.

Hitherto inaccessible multisubstituted thiochroman derivatives were constructed via the one-pot reaction of thiophenols with allylic alcohols catalyzed by 0.2 equiv triflic acid under metal-free conditions. A variety of thiochroman derivatives can be obtained by this straightforward protocol that allows the introduction of up to four substituents at various locations on the thiochroman skeleton.

Tandem double hydrophosphination of α,β,γ,δ-unsaturated-1,3-indandiones: diphosphine synthesis, mechanistic investigations and coordination chemistry.

A metal-free tandem double hydrophosphination of extended conjugated indandiones has been established. Mechanistic investigations confirmed the consecutive manner of the nucleophilic addition reaction. Complexation of the generated keto-diphosphine resulted in the formation of an unexpected tridentate bridging ligand with an anionic P,O-bidentate and a neutral P-monodentate coordination mode on two palladium units.

Catalytic and Mechanistic Developments of the Nickel(II) Pincer Complex-Catalyzed Hydroarsination Reaction.

Synthetic challenges have significantly slowed the development of the catalytic asymmetric hydroarsination reaction despite it being a highly attractive C-As bond formation methodology. In addition, there is a poor understanding of the main reaction steps in such reactions which limit further development in the field. Herein, key intermediates of the hydroarsination reaction catalyzed by a PCP Ni -Cl pincer complex are presented upon investigating the reaction with DFT calculations, conductivity measurements, NMR spectroscopy, and catalytic screening.

Investigating palladium pincer complexes in catalytic asymmetric hydrophosphination and hydroarsination.

Given the periodic relationship of phosphines and arsines, is remodeling the catalytic asymmetric hydrophosphination reaction an efficient manner to develop the corresponding hydroarsination reaction? Herein, a chiral PCP-Pd(ii) pincer complex adept at generating enantioenriched phosphines was examined in the asymmetric hydroarsination reaction. Under distinct conditions, tertiary phosphines and arsines were generated in excellent yields (P: 96%, As: 91%) and ees (P: 90%, As: 85%). While secondary arsine reagents were not direct substitutes for the analogous phosphines, important parameters were identified which increased yield and ee of the hydroarsination reaction.

Evaluation of ferrocenyl phosphines as potent antimalarials targeting the digestive vacuole function of Plasmodium falciparum.

Owing to their lipophilic nature and chemical stability, ferrocene and its derivatives have been widely explored as antimicrobial agents, in combination with other active chemical 'war heads'. A prime example is ferroquine, an analogue of chloroquine obtained by covalently bonding ferrocene to 4-aminoquinoline, which possesses superior efficacy against multi-drug resistant malaria parasites. Herein, we explored the possibility of combining the ferrocenyl moiety with a phosphine unit and the subsequent inclusion of gold(i) to derive a molecular framework with demonstrated potential in inhibiting parasitic diseases.

Challenges in cyclometalation: steric effects leading to competing pathways and η,η-cyclometalated iridium(iii) complexes.

The iridation of (R)-N,N-dimethyl-1-(1-naphthyl)ethylamine in the presence of a base afforded an assortment of products ranging from organic molecules to coordinated systems and cyclometalated complexes. The transformation affirmed the postulation where steric effects within the coordination sphere favor a β-hydride elimination-like decomposition pathway, competing alongside ortho-metalation, thus leading to iminium intermediates. The same procedure also generated an unprecedented carbocyclic η,η-cycloiridated species that could not be attained from the direct cyclometalation of its organic ligand.

Screening of ferrocenyl-phosphines identifies a gold-coordinated derivative as a novel anticancer agent for hematological malignancies.

The development of new organometallic compounds as anticancer agents is currently an active area of research. Here, we report the design, synthesis and characterization of a panel of 10 new ferrocenyl-phosphine derivatives (FD1-FD10) and the analysis of their anti-proliferative activities in hematolymphoid cells representing non-Hodgkin cutaneous T-cell lymphoma (CTCL). The gold-coordinated ferrocenyl-phosphine complex FD10 exhibited a significant and dose-dependent cytotoxicity in 4 different CTCL cell lines - HuT78, HH, MJ and MyLa.

Desymmetrization of Achiral Heterobicyclic Alkenes through Catalytic Asymmetric Hydrophosphination.

Asymmetric addition of diarylphosphines to oxa- and azabicyclic alkenes proceeded in the presence of a chiral phosphapalladacycle catalyst and a mild acid at room temperature to give exclusively the enantioenriched addition products in excellent yields and good selectivities. Three new chiral carbon centers were generated stereoselectively by the catalytic hydrophosphination reaction.

Low-valent magnesium(i)-catalyzed cyanosilylation of ketones.

The magnesium(i) complex [(Nacnac)Mg] was employed as a highly efficient catalyst for the cyanosilylation of a variety of ketones with trimethylsilyl cyanide under mild conditions. In contrast to the traditional stoichiometric use of magnesium(i) complexes, 1 provides the first example of a truly catalytic application of Mg(i) complexes.

Ytterbium-Catalyzed Hydroboration of Aldehydes and Ketones.

The well-defined heavy rare-earth ytterbium iodide complex 1 (LYbI) has been successfully employed as an efficient catalyst for the hydroboration of a wide range of aldehydes and ketones with pinacolborane (HBpin) at room temperature. The protocol requires low catalyst loadings (0.1-0.

Nickel catalyzed enantioselective hydroarsination of nitrostyrene.

A catalytic asymmetric hydroarsination reaction of an activated alkene viz. (E)-nitrostyrene was developed using chiral PCP Pt-, Pd- and Ni-pincer complexes as catalysts. The corresponding chiral tertiary arsine adduct was obtained in ees of up to 80% under mild reaction conditions using the PCP Ni-Cl pincer catalyst.

Efficient access to a designed phosphapalladacycle catalyst via enantioselective catalytic asymmetric hydrophosphination.

A chiral phosphine auxiliary was generated with excellent ee via catalytic asymmetric hydrophosphination of 3-(naphthalen-1-ylmethylene)pentane-2,4-dione. The subsequent metal complexation of the monophosphine yielded two different coordination complexes depending on the reaction conditions. The ortho-palladation of both coordination complexes resulted in the formation of a single dimeric phosphapalladacycle complex that could be further converted to the monomeric bisacetonitrile derivative.

Mechanistic insights into the role of PC- and PCP-type palladium catalysts in asymmetric hydrophosphination of activated alkenes incorporating potential coordinating heteroatoms.

The impact of the structural attributes of chiral PC- and PCP-palladium catalysts was investigated in the asymmetric hydrophosphination of various heterocycle-functionalized enone substrates. Due to the architecture of the catalysts, they are confronted with potential catalyst deactivation arising from the coordination of the electron-rich heteroatoms (P, O, N and S) to the metal center. A systematic variation of the location and identity of the heteroatoms demonstrated the impact of structural modifications on the substrates, which have a significant influence on both yields (16-99%) and enantioselectivities (0-99%).

The synthesis and efficient one-pot catalytic "self-breeding" of asymmetrical NC(sp(3))E-hybridised pincer complexes.

Cyclopalladation of the pyridyl-substituted chiral phosphine sulfide (N-P=S) and oxide (N-P=O) compounds afforded the asymmetric N-C(sp(3))*-S and N-C(sp(3))*-O pincer complexes. When applied as catalysts in asymmetric hydrophosphination, the newly developed aliphatic pincer catalyst could be recycled over three runs and obtained in large quantities via a one-pot "self-breeding" catalytic protocol.

Computational and carbon-13 NMR studies of Pt-C bonds in P-C-P pincer complexes.

A (13)C{(1)H} NMR based investigation was conducted to examine the electronic properties of C(aryl)-M bonds and their trans influence in P-C(aryl)-P pincer complexes. A series of structurally related platinum pincer complexes were rationally designed and their corresponding (13)C-(195)Pt coupling constants were systematically examined. By methodical substitution of the ligand trans to the organometallic C(aryl)-Pt bond, this study revealed the significant influence of the ligands on the nature of the C(aryl)-M bonds.

Palladacycle promoted base controlled regio- and enantioselective hydrophosphination of 2-pyridylacrylate/amide and the cytotoxicity of their gold complexes.

The regioselective asymmetric hydrophosphination of pyridine-functionalized alkenes can be achieved in the presence of stoichiometric amounts of the chiral palladium complex (R)-1. The presence or absence of base affords the respective β- and α-adducts with excellent regiocontrol. Chiral gold-phosphine complexes incorporating the adducts exhibited good in vitro anticancer activity against the breast cancer cell line MDA-MB-231.

Pd-catalyzed enantiodivergent and regiospecific phospha-Michael addition of diphenylphosphine to 4-oxo-enamides: efficient access to chiral phosphinocarboxamides and their analogues.

The palladacycle-catalyzed asymmetric P-H addition of 4-oxo-enamides has been developed, which provides efficient access to phosphinocarboxamides and their analogues. Solvent-mediated reversal of stereoselectivity (ee from +96% to -92%) was observed, and the underlying mechanism that allows facile access to both enantiomers of the product by judicious choice of solvents is revealed.

Palladium catalyzed asymmetric hydrophosphination of α,β- and α,β,γ,δ-unsaturated malonate esters - efficient control of reactivity, stereo- and regio-selectivity.

Both PC-cyclometalated and PCP-pincer type palladium catalysts have recently been found to be robust and efficacious catalysts for the asymmetric P-H addition reaction involving activated olefins. Our studies on the asymmetric P-H addition of diphenylphosphine to malonate ester and α,β,γ,δ-alkylidenemalonate ester revealed for the first time that the catalyst choice can have a dramatic impact in terms of reactivity as well as regio- and stereo-control for this asymmetric hydrofunctionalization reaction. Besides showing significantly contrasting reactivity and stereoselectivity in the hydrophosphination reaction involving malonate ester, in the case of α,β,γ,δ-alkylidenemalonate ester, a novel regiodivergent method was developed with the 1,4-adduct being obtained exclusively with the PC-catalyst while the pincer catalyst produced only the 1,6-adduct.