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We report the synthesis and study of trialkylsilylethyne-substituted "oblique" pyrene-fused acenes, carbon nanoribbons demonstrating near-IR absorption with reversible oxidation and reduction, and acene-like evolution of electronic properties upon extension of the aromatic core. Their electronic structures are investigated through DFT studies, which support the more delocalized nature of their frontier molecular orbitals compared to more common "vertical" pyrene systems. Despite a longer aromatic core, the more extended of the two examples demonstrates enhanced photostability compared to the shorter derivative, running counter to the trend in linear acenes. The unusual stability of the longer core is ultimately linked to its relatively low T1 energy inhibiting the generation of reactive O2 species. The byproduct generated upon photooxidation of the shorter nanoribbon appears to catalyze the generation of 1O2 due to its large T1 energy, leading to its relatively decreased stability. [ABSTRACT FROM AUTHOR]

Substituent size and isomerization play an important role in the polymorphism of 2-(naphthalen-n-ylamino)-benzoic acids (n = 1, 2; 2-NBAs) as each of the two previously investigated 2-NBAs was found to be polymorphic, while their parent compound fenamic acid (FA) has only one form discovered. 2-(Naphthalen-1-ylamino)-nicotinic acid (1) and 2-(naphthalen-2-ylamino)-nicotinic acid (2) (2-NNA) are isosteric compounds of 2-NBAs, and 2-(2,3-dimethyl-phenylamino)-nicotinic acid (3) and 2-(3,4-dimethyl-phenylamino)-nicotinic acid (4) are 2-NNA analogues with similar substitution patterns. All four compounds are clonixin analogues. The polymorphism of these four compounds was investigated. One solvent-free form (1-A) and one hydrate (1-H) were discovered for 1, three forms (2-I, 2-II, and 2-III) were obtained for 2, and one form was found for 3 and 4. The four systems were characterized by single-crystal XRD (SCXRD) and powder XRD (PXRD), and structural properties were compared among the crystals of the four compounds, their isosteres, and other related analogues. The phase behavior of the four systems was studied with differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) was used to investigate the dehydration of 1-H. Computational studies such as stable conformer search, π–π interaction energy calculation, and non-covalent interaction (NCI) analysis were performed to shed light on the rise of polymorphism, and the relative contribution of various intermolecular interactions to the overall stability of the crystals. The study confirmed the effect of substituent size, thus the consequent π–π interactions, on the hydrate formation of compound 1 and polymorphism of compound 2. [ABSTRACT FROM AUTHOR]

For more than two decades, the silylethyne functionalization scheme has been used to induce strong π-stacking interactions in linear acenes and heteroacenes. As part of our efforts to better understand the crystal engineering aspects of silylethyne functionalization, along with an interest in studying the impact of ring topology on the electronic and optical properties of heteroacenes, we describe here the integration of thieno[3,2-b]thiophene (a non-linear isomer of the well-known anthradithiophene) into our well established crystal engineering scheme. By utilizing the thienothiophene moiety coupled with an asymmetric solubilizing group (isopropenyldiisopropylsilylethyne), we were able to achieve charge carrier mobilities (l) upwards of 0.22 cm² V-1 s-1. Based on their increased stability and promising initial mobilities, the use of this thienothiophene moiety may offer a new approach to the formation of larger heteroacene analogues with more than 5 aromatic rings. [ABSTRACT FROM AUTHOR]

Emerging synthetic development of chiral gold(III) complexes has prompted new opportunities in catalysis and material science with limited utility in biomedicine. Here, we demonstrate potential chemotherapeutic capability of [C^N]Au(III)Cl(R-DuPhos) (1–7) complexes, containing 1,2-bis[(2R,5R)-2,5-dialkylphospholano]benzene, which shows good stabilty, potent anticancer activity, and tolerability in mice. [ABSTRACT FROM AUTHOR]

To probe the effect of substitution on the benzoic acid ring on the polymorphism of phenylaminobenzoic acids, five 3-methyl-2-(phenylamino)benzoic acids (MPABAs) were synthesized. A preliminary polymorph screen led to one form for compounds 1–4 and three forms and a solvate (5-I, 5-II, 5-III, and 5-S) for compound 5. This observation is similar to that of the structurally related compounds with no substitution on the benzoic acid ring. All crystal forms were characterized by single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), and FT-IR spectroscopy. The polymorphs of compound 5 were investigated in detail experimentally and theoretically. A conformational scan provided insight into the origin of polymorphism of 5. NBO calculations confirmed the composition and nature of the sigma bond character of the two N–C bonds in 5. Hirshfeld analysis accounted for the major intermolecular interactions contributing to the overall stability of the crystals. It is clear that conformational flexibility alone doesn't lead to polymorphism, and substitution position and pattern are the real determinant of polymorphism in the investigated compounds. [ABSTRACT FROM AUTHOR]

2-((2,6-Dichlorophenyl)amino)benzoic acid (2-DCABA), a potential non-steroidal anti-inflammatory drug and an analog of 2-((2,6-dimethylphenyl)amino)benzoic acid (HDMPA) was synthesized and its polymorphism was studied to investigate the effect of double Cl–CH3 exchange. Three forms-two polymorphs (I and II) and one cocrystal salt (S)-were obtained through polymorph screening in a variety of solvents, and the elusive single crystals of form II of HDMPA were harvested through melt crystallization. The crystal forms were characterized by single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), DSC, and FT-IR. Isomorphism and isostructurality were observed between the form I of each system. The polymorphism of 2-DCABA seems to stem from the conformational flexibility of the molecule, similar to that of HDMPA. Hirshfeld analysis revealed different intermolecular interactions contributing to the stability of the crystal form I of 2-DCABA and HDMPA-I, despite their structural similarity. [ABSTRACT FROM AUTHOR]

Addition of methyl group(s) to either or both aromatic rings of fenamic acid (FA) afforded three FA derivatives (1–3), designed to investigate the effect on the polymorphic behavior of these compounds exerted by substitution. A relatively comprehensive polymorph screen led to the discovery of four polymorphs for compound 3, for which substitution took place on both aromatic rings, in contrast to the production of either two or one form(s) for compounds 1 and 2, both of which are mono-substituted. The observation indicated that both substitution position and pattern are important in the polymorphism of these compounds. The thermal properties of each system were investigated by differential scanning calorimetry (DSC). Conformational scans and Hirshfeld surface analyses were performed to study the mechanism of polymorphism and the intermolecular interactions contributing to the stability of each crystal form. [ABSTRACT FROM AUTHOR]

Derived from the lateral fusion of benzene rings, acenes are a class of π-conjugated molecules containing a single aromatic sextet, where system size is inversely correlated with chemical stability. In the pursuit of creating graphene nanoribbons/nanowires, several extended-ring structures have been synthesized through linear combinations of azaacenes and pyrene. Importantly, these extended systems demonstrate enhanced chemical stability and allow for the construction of macromolecular-sized structures. Here, we present a combined quantum-chemical and experimental study to reveal the cost of these improved characteristics in fully carbon-based systems. The results clearly show that pyrene moieties inserted among acene units do not result in long acene-like structures, rather the pyrene-inserted acene is, electronically, a series of (nearly) isolated acenes. The origin of pyrene's electronic blocking effect and implications on oxidized and photoexcited states of these extended-ring systems are detailed. The results of this investigation definitively show that coupling pyrene in an orthogonal orientation (through the 4, 5/9, 10 positions or e/l faces) to acenes should be eschewed if nanographene-/nanowire-like structures are desired. [ABSTRACT FROM AUTHOR]

Highly oxidizing radical cation salts can be used as chemical oxidants in a wide variety of applications. While some are commercial and others can be made, stability has been a problem with many of these organic-based reagents. We sought a method to increase redox potentials of organic compounds, to yield radical cation salts that do not suffer the same instability as their triarylamine counterparts. Using phenothiazines, we (i) blocked the positions para to nitrogen with a substituent containing strong covalent bonds, using an electron-withdrawing group to increase oxidation potential, while at the same time (ii) introduced strain at the positions ortho to nitrogen to further raise the oxidation potential by preventing geometric relaxation of the oxidized state. Here we synthesized the phenothiazine derivative, N-ethyl-1,9-dimethyl-3,7-bis(trifluoromethyl)phenothiazine to test this hypothesis. Indeed, oxidation potentials reflect additive substituent effects, yielding a high-potential redox couple with a stable radical cation. Stability tests in solution and the solid state show that the radical cation form of this phenothiazinium is stable and can be used to oxidize other organic compounds in solution. [ABSTRACT FROM AUTHOR]

Androgen-deprivation therapy (ADT) is only a palliative measure, and prostate cancer invariably recurs in a lethal, castration-resistant form (CRPC). Prostate cancer resists ADT by metabolizing weak, adrenal androgens to growth-promoting 5α-dihydrotestosterone (DHT), the preferred ligand for the androgen receptor (AR). Developing small-molecule inhibitors for the final steps in androgen metabolic pathways that utilize 17-oxidoreductases required probes that possess fluorescent groups at C-3 and intact, naturally occurring functionality at C-17. Application of the Pictet–Spengler condensation to substituted 4-(2-aminoethyl)coumarins and 5α-androstane-3-ones furnished spirocyclic, fluorescent androgens at the desired C-3 position. Condensations required the presence of activating C-7 amino or N,N-dialkylamino groups in the 4-(2-aminoethyl)coumarin component of these condensation reactions. Successful Pictet–Spengler condensation, for example, of DHT with 9-(2-aminoethyl)-2,3,6,7-tetrahydro-1H,5H,11H-pyrano[2,3-f]pyrido[3,2,1-ij]quinolin-11-one led to a spirocyclic androgen, (3R,5S,10S,13S,17S)-17-hydroxy-10,13-dimethyl-1,2,2′,3′,4,5,6,7,8,8′,9,9′,10,11,12,12′,13,13′,14,15,16,17-docosahydro-7′H,11′H-spiro-[cyclopenta[a]phenanthrene-3,4′-pyrido[3,2,1-ij]pyrido[4′,3′:4,5]pyrano[2,3-f]quinolin]-5′(1′H)-one. Computational modeling supported the surrogacy of the C-3 fluorescent DHT analog as a tool to study 17-oxidoreductases for intracrine, androgen metabolism. [ABSTRACT FROM AUTHOR]

N-Ethyl-3,7-bis(trifluoromethyl)phenothiazine is a highly soluble redox shuttle for overcharge protection in lithium-ion batteries with an oxidation potential of ca. 3.8 V vs. Li+/0 in carbonate solvents. This compound has enabled extensive overcharge protection of LiFePO4/graphite cells and does so at high charging rates at high concentrations. Our initial synthesis of this compound suffered from low yields and difficult purifications. Here we report a cleaner, higher-yielding synthesis and additional characterization of the product and its stable radical cation salt. [ABSTRACT FROM AUTHOR]

Flunixin [2-(3-trifluoromethyl-2-methyl-phenylamino)-nicotinic acid, FLX], a potent nonsteroidal anti-inflammatory drug widely used in veterinary medicine, was found to exist in at least two crystal forms (I and II), in contrast to clonixin [2-(3-chloro-2-methyl-phenylamino)-nicotinic acid, CLX], which exists in four solvent-free forms and multiple solvates. Form I was harvested from a variety of solvents and characterized by single-crystal X-ray diffraction, PXRD, FT-IR, and Raman spectroscopy. Its crystal structure is sustained on the strong acid–pyridine hydrogen bond. Form II was generated by thermal treatment of form I. Other aspects of this polymorphic system were investigated both experimentally and theoretically. Quantum chemistry calculations were performed to shed light on the lack of polymorphism from solution-phase crystallization. Conformational scan of the dihedral angle C2–N7–C8–C9 (τ) revealed two stable conformations, one with τ near 170°, and the other near 70°, corresponding to the molecule in the crystal. Hirshfeld analysis accounted for the major intermolecular interactions contributing to the overall stability of the crystal. [ABSTRACT FROM AUTHOR]

The reactivity of bidentate AuIII–Cl species, [(C^N)AuCl2], with a bisphosphine or carbon donor ligands results in reductive elimination. Combined experimental and computational investigations lead to the first evidence of a direct intramolecular C(sp2)–N(sp2) bond formation from a monomeric [(C^N)AuCl2] gold(iii) complex. We show that bidentate ligated Au(iii) systems bypass transmetallation to form C(sp2)–N(sp2) species and NHC–Au–Cl. Mechanistic investigations of the reported transformation reveal a ligand-induced reductive elimination via a key AuIII intermediate. Kinetic studies of the reaction support a second-order rate process. [ABSTRACT FROM AUTHOR]

The reactivity of tetrachloroauric acid (HAuCl4) with readily accessible bidentate N-donor ligands affords N,N-ligated Au(iii) center complexes. These compounds are useful precursors of stable catalysts, anticancer agents, and building blocks for materials. This report provides detailed insight into intermediates, equilibria, the counter anion effect, and structural variability, using spectroscopy, crystallography and computational tools. Novel mixed-valence Au(i) and Au(iii) complexes [Au(o-phen)Cl2]2[AuCl2][AuCl4] and [Au(o-phen)Cl2][AuCl2] having AuCl2− and AuCl4− anions linearly arranged in the axial sites of the square-planar Au(o-phen)Cl2 cation were discovered. Other competing side products of the reaction studied revealed protonated N,N-bidentate ligands with AuCl4− anions. Quantitative variable temperature NMR studies reveal that for a mixture of target Au(iii) salt and the protonated ligand, the reaction favors the irreversible formation of the side product. Using a rapid (30 min) temperature controlled protocol, the desired coordinated species is accessible in respectable yields while avoiding side products. [ABSTRACT FROM AUTHOR]

Coordination complexes can be used to photocage biologically active ligands, providing control over the location, time, and dose of a delivered drug. Dual action agents can be created if both the ligand released and the ligand-deficient metal center effect biological processes. Ruthenium(ii) complexes coordinated to pyridyl ligands generally are only capable of releasing one ligand in H2O, wasting equivalents of drug molecules, and producing a Ru(ii) center that is not cytotoxic. In contrast, Ru(ii) polypyridyl complexes containing diazine ligands eject both monodentate ligands, with the quantum yield (ΦPS) of the second phase varying as a function of ligand pKa and the pH of the medium. This effect is general, as it is effective with different Ru(ii) structures, and demonstrates that diazine-based drugs are the preferred choice for the development of light-activated dual action Ru(ii) agents. [ABSTRACT FROM AUTHOR]

Through structural modification of 2-anilinonicotinic acid by isomerization, the ΔpKa between the carboxylic acid and pyridinium NH increased dramatically over the threshold to form zwitterions in the newly designed 4-anilinonicotinic acids. This in turn led to the formation of a hydrogen bond between carboxylate and pyridinium NH, and the absence of two commonly observed synthons, i.e., the acid–acid homosynthon and acid–pyridine heterosynthon. The new synthon has a stronger hydrogen bond than the acid–acid homosynthon and the acid–pyridine heterosynthon, as suggested by theoretical calculations. This, together with the much larger ΔpKa, explains its formation. [ABSTRACT FROM AUTHOR]

Stable electron-donating organic compounds are of interest for numerous applications that require reversible electron-transfer reactions. Although many organic compounds are stable one-electron donors, removing a second electron from a small molecule to form its dication usually leads to rapid decomposition. For cost-effective electrochemical energy storage utilizing organic charge-storage species, the creation of high-capacity materials requires stabilizing more charge whilst keeping molecular weights low. Here we report the simple modification of N-ethylphenothiazine, which is only stable as a radical cation (not as a dication), and demonstrate that introducing electron-donating methoxy groups para to nitrogen leads to dramatically improved stability of the doubly oxidized (dication) state. Our results reveal that this derivative is more stable than an analogous compound with substituents that do not allow for further charge delocalization, rendering it a promising scaffold for developing atom-efficient, two-electron donors. [ABSTRACT FROM AUTHOR]

Quantitative singlet fission has been observed for a variety of acene derivatives such as tetracene and pentacene, and efforts to extend the library of singlet fission compounds is of current interest. Preliminary calculations suggest anthradithiophenes exhibit significant exothermicity between the first optically-allowed singlet state, S1, and 2 × T1 with an energy difference of ＞5000 cm−1. Given the fulfillment of this ingredient for singlet fission, here we investigate the singlet fission capability of a difluorinated anthradithiophene dimer (2ADT) covalently linked by a (dimethylsilyl)ethane bridge and derivatized by triisobutylsilylethynyl (TIBS) groups. Photophysical characterization of 2ADT and the single functionalized ADT monomer were carried out in toluene and acetone solution via absorption and fluorescence spectroscopy, and their photo-initiated dynamics were investigated with time-resolved fluorescence (TRF) and transient absorption (TA) spectroscopy. In accordance with computational predictions, two conformers of 2ADT were observed via fluorescence spectroscopy and were assigned to structures with the ADT cores trans or cis to one another about the covalent bridge. The two conformers exhibited markedly different excited state deactivation mechanisms, with the minor trans population being representative of the ADT monomer showing primarily radiative decay, while the dominant cis population underwent relaxation into an excimer geometry before internally converting to the ground state. The excimer formation kinetics were found to be solvent dependent, yielding time constants of ∼1.75 ns in toluene, and ∼600 ps in acetone. While the difference in rates elicits a role for the solvent in stabilizing the excimer structure, the rate is still decidedly long compared to most singlet fission rates of analogous dimers, suggesting that the excimer is neither a kinetic nor a thermodynamic trap, yet singlet fission was still not observed. The result highlights the sensitivity of the electronic coupling element between the singlet and correlated triplet pair states, to the dimer conformation in dictating singlet fission efficiency even when the energetic requirements are met. [ABSTRACT FROM AUTHOR]

A series of new polycyclic aromatic hydrocarbon compounds based on (4,10-disubstituted-dibenzo[def,mno]chrysene-6,12-dione) and 4,10 di-substituted 6,12-bis(triisopropylsilylethynyl)dibenzo[def,mno]chrysene are reported with tunable electronic properties through varied molecular architecture. Starting with an inexpensive commercially available textile dye known as Vat Orange #3, (4,10-dibromo-dibenzo[def,mno] chrysene-6,12-dione) we extended the conjugation at the 4- and 10-positions by the attachment of both electron rich and deficient hexylvinylphthalimide, thiophene, hexylthiophene, triphenylamine, and hexylbithiophene aromatic groups, and studied the resultant optoelectronic properties. By applying various synthetic metal-catalyzed reactions, soluble dibenzo[def,mno]chrysene and dibenzo[def,mno]chrysene-6,12-dione derivatives were achieved with optical edge band gaps between 2.30 eV and 1.65 eV. [ABSTRACT FROM AUTHOR]

Chlorine can participate in numerous interactions such as halogen bonding, hydrogen bonding, and London dispersion in the solid state. In this work, we report the influence of a chlorine substituent on the polymorphism of a potential anticancer drug, 4-chloro-phenylanthranilic acid (CPAA). Three polymorphs have been discovered for this compound, and the three forms were characterized by single-crystal X-ray diffraction, power X-ray diffraction (PXRD), FT-IR, and Raman spectroscopy. Both conformational flexibility of the molecule and the sp2CH…Cl hydrogen bond seem to lead to the polymorphism of the system. The phase behavior was investigated by differential scanning calorimetry (DSC), with the conclusion that form II converts to III upon heating. A conformational scan shows the conformational minima corresponds to the conformers existing in the polymorphs. Lattice energy calculations show energies of −106.70, −104.72, and −194.42 kJ mol−1 for forms I to III, providing information on relative stability for each form. Hirshfeld analysis revealed that intermolecular interactions such as H…H, C…H, H…Cl, and H…O contribute to the stability of the crystal forms. [ABSTRACT FROM AUTHOR]

We report substituent effects on conformational preferences and hole mobilities of 2,5-bis-(thiophen-2-yl)thieno[3,2-b]thiophenes (BTTT) monomer and dimer, and hexyl derivatives. We employ single-crystal X-ray diffraction, quantum mechanical calculations, and thin-film transistors to explore the difference between monomer, dimer, and effect of hexyl substitution. The hexyl-substituted molecules show marked differences in solid-state packing compared to the unsubstituted analogs. Most notably, the alkylated monomer crystal structure exhibits terminal thiophenes in the syn conformation. In contrast, the unsubstituted monomer adopts the more common anti conformation. The hexyl-substituted dimer, however, features a mixture of syn and anti thiophenes. Gas phase conformations of oligomers rationalize the intrinsic conformational preferences. We use a multimode simulation to compute hole mobilities and find excellent agreement with experiment. Theoretical results support our hypothesis that alkyl side chains cause these small molecules to adopt orientations that enhance hole mobilities by an order of magnitude upon hexyl substitution of the monomer. [ABSTRACT FROM AUTHOR]

Electron-withdrawing substituents are introduced onto the phenothiazine core to raise its oxidation potential for use as a redox shuttle in high-voltage lithium-ion batteries. A perfluorinated derivative oxidizes at 4.3 V vs. Li+/0, and functions for ca. 500 h of 100% overcharge in LiNi0.8Co0.15Al0.05O2/graphite coin cells at a charging rate of C/10. [ABSTRACT FROM AUTHOR]

Two new small-molecule enzyme mimics of carbonic anhydrase were prepared and characterized. These complexes contain the salen-like ligand bis(hydroxyphenyl)phenanthroline. This ligand is similar to the salen-type ligands previously incorporated into carbonic anhydrase mimics but contains no hydrolyzable imine groups and therefore serves as a promising ligand scaffold for the synthesis of a more robust CO2 hydration catalyst. These homogeneous catalysts were investigated for CO2 hydration in concentrated primary amine solutions through which a dilute CO2 (14%) fluid stream was flowed and showed exceptional activity for increased CO2 absorption rates. [ABSTRACT FROM AUTHOR]

Anthradithiophenes (ADTs) are typically synthesized as inseparable mixtures of regioisomers. In this paper, we describe the synthesis of desymmetrized anthradithiophenes containing one trialkylsilylethyne solubilizing group, which allowed chromatographic separation of the three resulting isomers. Cyclic voltammograms, as well as absorption and emission spectra for all isomers, were nearly identical. However, X-ray crystallography revealed that the positions of the sulfur atoms in each isomer strongly influence crystal packing, corroborating calculations that show the S–π interaction to be less stabilizing than the C–H–π interaction. Isomer 3c packs in a pseudo 1-D fashion while isomers 3a and 3b pack as isolated π-stacked pairs. Isomer 3c shows a field-effect mobility four orders of magnitude higher than isomers 3a and 3b, presumably due to this difference in packing motif. [ABSTRACT FROM AUTHOR]

Understanding the solid-state structure of the bulk heterojunction provides insight into how to improve the performance of nonfullerene acceptors in organic solar cells. We have characterized the self-assembly of three functionalized pentacene acceptors in single crystals, neat films and bulk heterojunctions formed by blending with a diketopyrrolopyrrole-based molecular donor. Atomic force microscopy, grazing incidence wide-angle X-ray scattering and optical spectroscopy indicate that the presence of the donor perturbs the packing and texture of acceptors with smaller substituents. The structural characterization explains the differences in performance among the three acceptors studied and suggests that, unlike fullerenes, disordered domains of molecular acceptors with planar molecular structure have inefficient electron transport in BHJ thin films. [ABSTRACT FROM AUTHOR]

Three polymorphs (I, II, and III) have been discovered for 3-chloroisonicotinic acid. The torsion angle between the aromatic ring and the carboxylic acid in form I differs from that of forms II and III, which are similar. All three polymorphs form hydrogen-bonded chains based on the acid–pyridine heterosynthon. Despite the conformational similarity between forms II and III, the hydrogen-bonded chains in form II alternate in direction while those in form III all point in the same direction. Study of the phase behaviors of the three forms by differential scanning calorimetry, hot-stage microscopy, and thermogravimetric analysis revealed two solid-to-solid phase transitions from the metastable forms II and III to the most stable form I. Sublimation of 3-chloroisonicotinic acid also led to form I. A higher-temperature polymorph seemed to be possible but remained elusive. Lattice energy and hydrogen bonding strength calculations provided further insight into the stability of the polymorphs. A search of conformational space for the molecule suggested possibly additional polymorphs of this simple compound. The system may be valuable for further solid-state structure–property relationship studies. [ABSTRACT FROM AUTHOR]

3,7-Disubstituted N-ethylphenothiazine derivatives were synthesized as redox shuttle candidates for lithium-ion batteries. Battery cycling results show that three derivatives prevent overcharge. [ABSTRACT FROM AUTHOR]

Ru(bpy)2dppz, a well studied “light-switch” metal complex, transforms into a photochemical “light-switch” and DNA damaging agent by incorporating structural strain. This distorted compound is photoreactive and ejects a ligand upon binding duplex and G-quadruplex DNA, producing a reactive metal center that metalates the DNA. [ABSTRACT FROM AUTHOR]

Towards the goal of generating new stabilized gold complexes as potent anticancer agents, we report here a novel class of Au(I) agents from Au(III)-mediated C aryl -P bond formation captured within the same complex by reacting a C^N cyclometalated Au(III) complex with bisphosphines. Cyclometalated Au(III) complexes of the type [Au(C^N)Cl 2 ], where C^N represent different aryl pyridine framework reacted with bis(2-diphenylphosphino)phenyl ether in refluxing methanol to access an unsymmetrical gold complex featuring C-P coupling and Au(I)-phosphine. The complexes were characterized by 1 H-NMR, 13 C-NMR, and 31 P-NMR and mass spectrometry. The structures of the complexes were characterized by X-ray crystallography and purity ascertained by HPLC and elemental analysis. The complexes demonstrate promising anticancer activity in a broad panel of cancer cell lines of different tumor origin. Mechanistically, the complexes induce apoptosis, generate mitochondrial ROS, depolarize mitochondrial membrane potential and modulate mitochondrial respiration in cancer cells. Overall, we developed a new structural class of Au(I) complexes with promising anticancer potential with potential utility in other applications.

Glioblastoma multiforme (GBM) is the most lethal brain cancer subtype, often advanced by the time of initial diagnosis. Existing treatment modalities including surgery, chemotherapy and radiation have been stymied by recurrence, metastasis, drug resistance and brain targetability. Here, we report a geometrically distinct Au(i) complex ligated by N^N-bidentate ligands and supported by a N-heterocyclic ligand that modulates mitochondrial morphology to inhibit GBM in vitro and in vivo . This work benefits from the facile preparation of anti-GBM Au(i)-NHC complexes., Competing Interests: Samuel G. Awuah reports that financial support was provided by University of Kentucky. Samuel G. Awuah reports a relationship with University of Kentucky that includes funding grants. Samuel G. Awuah has patents pending in the University of Kentucky Research Foundation., (This journal is © The Royal Society of Chemistry.)