A Broadened Class of Donor-Acceptor Stacked Macrometallacyclic Adducts of Different Coinage Metals.

A yet-outstanding supramolecular chemistry challenge is isolation of novel varieties of stacked complexes with finely-tuned donor-acceptor bonding and optoelectronic properties, as herein reported for binary adducts comprising two different cyclic trinuclear complexes (CTC@CTC'). Most previous attempts focused only on 1-2 factors among metal/ligand/substituent combinations, resulting in heterobimetallic complexes. Instead, here we show that, when all 3 factors are carefully considered, a broadened variety of CTC@CTC' stacked pairs with intuitively-enhanced intertrimer coordinate-covalent bonding strength and ligand-ligand/metal-ligand dispersion are attained (d 2.

A Copper-Based Metal-Organic Framework for Selective Separation of C2 Hydrocarbons from Methane at Ambient Conditions: Experiment and Simulation.

C2 hydrocarbon separation from methane represents a technological challenge for natural gas upgrading. Herein, we report a new metal-organic framework, [CuL(DEF)]·2DEF (; HL = 4,4',4″,4‴-((1,1',1″,1‴)-benzene-1,2,4,5-tetrayltetrakis(ethene-2,1-diyl))tetrabenzoic acid; DEF = ,-diethylformamide; UNT = University of North Texas). The linker design will potentially increase the surface area and adsorption energy owing to π(hydrocarbon)-π(linker)/M interactions, hence increasing C2 hydrocarbon/CH separation.

Naphthodithiophene-Fused Porphyrins: Synthesis, Characterization, and Impact of Extended Conjugation on Aromaticity.

The fusion of tetrapyrroles with aromatic heterocycles constitutes a useful tool for manipulating their opto-electronic properties. In this work, the synthesis of naphthodithiophene-fused porphyrins was achieved through a Heck reaction-based cascade of steps followed by the Scholl reaction. The naphthodithiophene-fused porphyrins display a unique set of optical and electronic properties.

Fluorinated Antimony(V) Tetraarylporphyrins as High-Valent Electron Acceptors with Unparalleled Reduction Potentials.

A series of fluorinated antimony(V) porphyrins, SbTPP(OMe)·PF, SbTPP(OTFE)·PF, SbT(4F)PP(OMe)·PF, SbT(35F)PP(OMe)·PF, SbT(345F)PP(OMe)·PF, SbT(4CF)PP(OMe)·PF, SbT(35CF)PP(OMe)·PF, and SbT(35CF)PP(OTFE)·PF, have been synthesized with phenyl [P], 4-fluorophenyl [(4F)P], 3,5-difluorophenyl [(35F)P], 3,4,5-difluorophenyl [(345F)P], 4-trifluoromethylphenyl [(4CF)P], and 3,5-bis(trifluoromethyl)phenyl [(35CF)P], in the meso-positions. Additionally, the SbTPP(OTFE)·PF and SbT(35CF)PP(OTFE)·PF carry trifluoroethoxy units in their axial-positions. The fluorination on the porphyrin peripherals ranges from zero fluorine atoms in SbTPP(OMe)·PF to 30 fluorine atoms in SbT(35CF)PP(OTFE)·PF.

Unsymmetric Pentacene- and Pentacenequinone-Fused Porphyrins: Understanding the Effect of Cross- and Linear-Conjugation.

Unsymmetric pentacenequinone-fused (cross-conjugated) and pentacene-fused (linear-conjugated) porphyrins were designed and synthesized. The cross-conjugated ( - ) and linear-conjugated ( - ) porphyrins displayed strikingly different sets of optical and electronic properties, both of which are unusual and nontypical of porphyrins. MCD, DFT, and TDDFT calculations suggest that multiple charge transfer states exist in both π-conjugated systems, which contributes to the complex absorption and MCD spectra of these molecular systems.

Three Component Cascade Reaction of Cyclohexanones, Aryl Amines, and Benzoylmethylene Malonates: Cooperative Enamine-Brønsted Acid Approach to Tetrahydroindoles.

A three-component cascade reaction comprising cyclic ketones, arylamines, and benzoylmethylene malonates has been developed to access 4,5,6,7-tetrahydro-1-indoles. The reaction was achieved through cooperative enamine-Brønsted catalysis in high yields with wide substrate scopes. Mechanistic studies identified the role of the Brønsted acid catalyst and revealed the formation of an imine intermediate, which was confirmed by X-ray crystallography.

1-(2-Methyl-phen-yl)-4,4'-bipyridin-1-ium tetra-fluorido-borate.

Crystals of the title compound, CHN ·BF , were unexpectedly grown from crystallization attempts of [Pt(4,4'-bpy)](BF) [Smith (2019 ▸). , 188-215] using toluene and aceto-nitrile. The tetra-fluoro-borate anion and the central pyridinium ring of the cation are disordered, with atomic site occupancies close to ½.

Hypervalent Phosphorus(V) Porphyrins with -Methoxyphenyl Substituents: Significance of the Number and Position of Methoxy Groups in Promoting Intramolecular Charge Transfer.

To study the photophysical and redox properties as a function of -aryl units, a series of hypervalent phosphorus(V) porphyrins, PP(OMe)·PF, PMP(OMe)·PF, PDMP(OMe)·PF, P345TMP(OMe)·PF, and P246TMP(OMe)·PF, with phenyl (P), 4-methoxyphenyl (MP), 3,5-dimethoxyphenyl (DMP), 3,4,5-trimethoxyphenyl (345TMP), and 2,4,6-trimethoxyphenyl (246TMP) units, respectively, have been synthesized. The P(+5) in the cavity makes the porphyrin ring electron-poor, whereas the methoxy groups make the -phenyl rings electron-rich. The presence of electron-rich and electron-poor portions within the porphyrin molecule promoted an intramolecular charge transfer (ICT).

Aromatic heterobicycle-fused porphyrins: impact on aromaticity and excited state electron transfer leading to long-lived charge separation.

A new synthetic method to fuse benzo[4,5]imidazo[2,1-]isoindole to the porphyrin periphery at the β,β-positions has been developed, and its impact on the aromaticity and electronic structures is investigated. Reactivity investigation of the fused benzoimidazo-isoindole component reveals fluorescence quenching of a zinc porphyrin (AMIm-2) upon treatment with a Brønsted acid. The reaction of the zinc porphyrin (AMIm-2) with methyl iodide initiated a new organic transformation, resulting in the ring-opening of isoindole with the formation of an aldehyde and dimethylation of the benzoimidazo component.

Antimony(+5) ion induced tunable intramolecular charge transfer in hypervalent antimony(V) porphyrins.

The +5 oxidation state of antimony induced push-pull style intramolecular charge transfer in an elegantly designed axial dimethoxyantimony(V) porphyrin series: SbP(OMe)·PF, SbMP(OMe)·PF, SbDMP(OMe)·PF, SbTMP(OMe)·PF with phenyl (P), 4-methoxyphenyl (MP), 3,5-dimethoxyphenyl (DMP), and 3,4,5-trimethoxyphenyl (TMP) units, respectively, in its positions. The Sb(+5) made the porphyrin ring electron-poor, whereas the methoxy groups on the phenyl unit produced electron-rich sites within the molecule. The presence of electron-poor and electron-rich parts in the same molecule resulted in a push-pull type intramolecular charge transfer (ICT).

Asymmetric Synthesis of Chromans Through Bifunctional Enamine-Metal Lewis Acid Catalysis.

Cooperative enamine-metal Lewis acid catalysis has emerged as a powerful tool to construct carbon-carbon and carbon-heteroatom bond forming reactions. A concise synthetic method for asymmetric synthesis of chromans from cyclohexanones and salicylaldehydes has been developed to afford tricyclic chromans containing three consecutive stereogenic centers in good yields (up to 87 %) and stereoselectivity (up to 99 % ee and 11 : 1 : 1 dr). This difficult organic transformation was achieved through bifunctional enamine-metal Lewis acid catalysis.

Singlet Oxygen Generation in Peripherally Modified Platinum and Palladium Porphyrins: Effect of Triplet Excited State Lifetimes and meso-Substituents on O Quantum Yields.

A series of meso-substituted with aromatic (=tolyl, pyrenyl, fluorenyl, naphthyl, and triphenylamine) substituents, platinum (Pt), and palladium (Pd) porphyrins have been synthesized and characterized by spectroscopic and single-crystal X-ray diffraction studies to probe structure-reactivity aspects on the electrochemical redox potentials, and phosphorescence quantum yields and lifetimes. In the X-ray structures, the aromatic meso-substituents were rotated to some extent from the planarity of the porphyrin ring to minimize steric hindrance. Both Pt and Pd porphyrins revealed higher electrochemical redox gaps as compared to their free-base porphyrin analogs as a result of the harder oxidation and reduction processes.

Can Primary Arylamines Form Enamine? Evidence, α-Enaminone, and [3+3] Cycloaddition Reaction.

The formation of enamine from primary arylamines was detected and confirmed by nuclear magnetic resonance spectroscopy. The presence of a radical quencher, e.g.

Formal oxo- and aza-[3 + 2] reactions of α-enaminones and quinones: a double divergent process and the roles of chiral phosphoric acid and molecular sieves.

A double divergent process has been developed for the reaction of α-enaminones with quinones through facile manipulation of catalyst and additive, leading to structurally completely different products. The two divergent processes, which involve formal aza- and oxo-[3 + 2] cycloaddition reactions, are mediated by chiral phosphoric acid and molecular sieves, respectively. While inclusion of phosphoric acid in the reaction switched the reaction pathway to favor the efficient formation of a wide range of -substituted indoles, addition of 4 Å molecular sieves to the reaction switched the reaction pathway again, leading to enantioselective synthesis of 2,3-dihydrobenzofurans in excellent yields and enantioselectivities under mild conditions.

Sc(OTf)-Catalyzed Formal [3 + 3] Cycloaddition Reaction of Diaziridines and Quinones for the Synthesis of Benzo[][1,3,4]oxadiazines.

A formal [3 + 3] cyclization reaction of diaziridines and quinones has been developed offering 1,3,4-oxadiazinanes in generally high yields (up to 96%). The reaction was catalyzed by Sc(OTf) with a large substrate scope for both diaziridines and quinones. The synergistic activation of 1,3-dipolar diaziridines and the dipolar quinones was found to be essential to enable this reaction.

Nickel(II) Bisporphyrin-Fused Pentacenes Exhibiting Abnormal High Stability.

A series of largely π-extended multichromophoric molecules including cross-conjugated, half cross-conjugated, conjugation-interrupted and linearly conjugated systems were synthesized and characterized. These multichromophoric molecular systems revealed interesting structural-property relationships. Bisporphyrin-fused pentacenes Pen-1 b and Pen-2 a showed rich redox chemistry with 7 and 8 observable redox states, respectively.

Binary Donor-Acceptor Adducts of Tetrathiafulvalene Donors with Cyclic Trimetallic Monovalent Coinage Metal Acceptors.

Reactions between the π-acidic cyclic trimetallic coinage metal(I) complexes {[Cu(μ-3,5-(CF)pz)], {[Ag(μ-3,5-(CF)pz)], and {[Au(μ-3,5-(CF)pz)] with TTF, DBTTF and BEDT-TTF give rise to a series of coinage metal(I)-based new binary donor-acceptor adducts {[Cu(μ-3,5-(CF)pz)]DBTTF} (), {[Ag(μ-3,5-(CF)pz)]DBTTF} (), {[Au(μ-3,5-(CF)pz)]DBTTF} (), {[Cu(μ-3,5-(CF)pz)]TTF} (), {[Ag(μ-3,5-(CF)pz)]TTF} (), {[Au(μ-3,5-(CF)pz)]TTF} (), {[Cu(μ-3,5-(CF)pz)]BEDT-TTF} (), {[Ag(μ-3,5-(CF)pz)]BEDT-TTF} (), and {[Au(μ-3,5-(CF)pz)]BEDT-TTF} (), where pz = pyrazolate, TTF = tetrathiafulvalene, DBTTF = dibenzotetrathiafulvalene, and BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene. This series of binary donor-acceptor adducts has been found to exhibit remarkable supramolecular structures in both the solid state and solution, whereby they exhibit supramolecular stacked chains and oligomers, respectively. The supramolecular solid-state and solution binary donor-acceptor adducts also exhibit superior shelf stability under ambient laboratory storage conditions.

New molecular architectures containing low-valent cluster centres with di- and trimetalated 2-vinylpyrazine ligands: synthesis and molecular structures of Ru(CO)(μ-CHNCH[double bond, length as m-dash]CH)(μ-H) and Ru(CO)(μ-CHNCH[double bond, length as m-dash]C)(μ-H).

Reaction of 2-vinylpyrazine with Ru(CO) results in multiple C-H bond activations to afford penta- and octa-ruthenium clusters, Ru(CO)(μ-CHNCH[double bond, length as m-dash]CH)(μ-H) (2) and Ru(CO)(μ-CHNCH[double bond, length as m-dash]C)(μ-H) (3), in which a Ru sub-unit is linked to Ru and Ru centres di- and tri-metalated 2-vinylpyrazine ligands, exhibiting novel coordination modes including the loss of ring aromaticity in 2. The bonding of 2 and the mechanism for the fluxional behaviour of the hydrides have been examined by electronic structure calculations.

Asymmetric diosmium sawhorse complexes.

Three asymmetric diosmium(I) carbonyl sawhorse complexes have been prepared by microwave heating. One of these complexes is of the type Os(μ-OCR)(μ-OCR')(CO)L, with two different bridging carboxylate ligands, while the other two complexes are of the type Os(μ-OCR)(CO)L, with one axial CO ligand and one axial phosphane ligand. The mixed carboxylate complex Os(μ-acetate)(μ-propionate)(CO)[P(p-tolyl)], (1), was prepared by heating Os(CO) with a mixture of acetic and propionic acids, isolating Os(μ-acetate)(μ-propionate)(CO), and then replacing two CO ligands with two phosphane ligands.

Convenient framework of poly functionalized (E)-2-benzylideno-(Z)-carbazolylideno cyanoacetamides via rearrangements as an efficient antibiofilm inhibitors with SAR study.

A simple and one-pot approach for the synthesis of highly functionalized novel (E)-2-benzylideno-(Z)-carbazolylideno cyanoacetamide derivatives from different 2-(2',3',4',9'-tetrahydro-carbazol-1'-ylidene)-propanedinitriles and aryl/heteroaryl carbaldehydes via vinylogous aldol reaction. The structures of the molecules were designated by FT-IR, H NMR, C NMR studies, elemental and X-ray crystallographic analysis. The synthesized pure products have been screened for in vitro antibiofilm inhibitory activity towards antibiotic-resistant pathogenic organisms.

Magnetic ordering in a vanadium-organic coordination polymer using a pyrrolo[2,3-:5,4-']bis(thiazole)-based ligand.

Here we present the synthesis and characterization of a hybrid vanadium-organic coordination polymer with robust magnetic order, a Curie temperature of ∼110 K, a coercive field of ∼5 Oe at 5 K, and a maximum mass magnetization of about half that of the benchmark ferrimagnetic vanadium(tetracyanoethylene) (V·(TCNE)). This material was prepared using a new tetracyano-substituted quinoidal organic small molecule 7 based on a tricyclic heterocycle 4-hexyl-4-pyrrolo[2,3-:5,4-']bis(thiazole) (C-PBTz). Single crystal X-ray diffraction of the 2,6-diiodo derivative of the parent C-PBTz, showed a disordered hexyl chain and a nearly linear arrangement of the substituents in positions 2 and 6 of the tricyclic core.

New Coordination Polymers of Copper(I) and Silver(I) with Pyrazine and Piperazine: A Step Toward "Green" Chemistry and Optoelectronic Applications.

Five coordination polymers and one hexanuclear cluster have been obtained, and their crystal structures were determined upon reaction of Cu(I) or Ag(I) precursors with pyrazine (Pyz) or piperazine (Ppz). Five complexes are mixed-imine-ligand with anionic-fluorinated pyrazolate [3,5-(CF)Pz] ([Pz]) besides Pyz or Ppz, whereas the sixth had the neutral diimine as a single chromophore. Complexes 1-3 are isomers of the same Cu/Pz/Pyz composition with the same or different unit cell stoichiometry, namely, {Cu[3,5-(CF)Pz](Pyz)(CHCl)} (1·CHCl), {Cu[3,5-(CF)Pz]}(Pyz)·toluene} (2·toluene), and {Cu[3,5-(CF)Pz](Pyz)·1.

Mixed-valence dimolybdenum complexes containing hard oxo and soft carbonyl ligands: synthesis, structure, and electrochemistry of Mo(O)(CO)(μ-κ-S(CH)S)(κ-diphosphine).

Mixed-valence dimolybdenum complexes Mo2(O)(CO)2{μ-κ2-S(CH2)nS}2(κ2-Ph2P(CH2)mPPh2) (n = 2, 3; m = 1, 2) (1-4) have been synthesized from one-pot reactions of fac-Mo(CO)3(NCMe)3 and dithiols, HS(CH2)nSH, in the presence of diphosphines. The dimolybdenum framework is supported by two thiolate bridges, with one molybdenum carrying a terminal oxo ligand and the second two carbonyls. The dppm (m = 1) products exist as a pair of diastereomers differing in the relative orientation of the two carbonyls (cis and trans) at the Mo(CO)2(dppm) center, while dppe (m = 2) complexes are found solely as the trans isomers.

Crystal structure of bis-(aceto-nitrile-κ)(4,4'-di--butyl-2,2'-bi-pyridine-κ,')platinum(II) bis-(tetra-fluorido-borate) packing as head-to-head dimers.

The crystal structure of a platinum(II) supra-molecular building block, [Pt(dbbpy)(NCCH)](BF) (dbbpy = 4,4'-di--butyl-2,2'-bi-pyridine, CHN) is an example of a rare head-to-head dimer, even with the bulky -butyl groups of the bi-pyridine. This packing motif still enables significant π-π inter-actions between two pyridyl groups, and may result from the close proximity of the tetra-fluorido-borate ions to the platinum(II) complexes, resulting in intra-molecular H⋯F distances between 2.156 and 2.

Design and synthesis of novel pyrrolo[2,3-a]carbazoles: 7-Chloro-2-oxo-3a-(2'-oxo-2',3'-dihydro-1'H-indol-3'-yl)-2,3,3a,4,5,10-hexahydro-pyrrolo[3,2-a]carbazole-1-carbonitrile as an efficient anticancer agent.

Highly efficient poly functionalized pyrrolo[3,2-a]carbazoles via ring contraction through rearrangement and intramolecular Michael addition reaction using one pot multicomponent reaction (MCR) is reported for the first time. Free radical scavenging and anticancer activities were determined by DPPH and MTT assays respectively. Of these, compound 8d exhibited most potent activity against HCT-15 human colon cancer cell lines with an IC value of 9.