Novel Type Of Compound Research Articles

Pd8 Nanocluster with Nonmetal‐to‐Metal‐ Ring Coordination and Promising Photothermal Conversion Efficiency

AbstractConstructing ambient‐stable, single‐atom‐layered metal‐based materials with atomic precision and understanding their underlying stability mechanisms are challenging. Here, stable single‐atom‐layered nanoclusters of Pd were synthesized and precisely characterized through electrospray ionization mass spectrometry and single‐crystal X‐ray crystallography. A pseudo‐pentalene‐like Pd8 unit was found in the nanocluster, interacting with two syn PPh units through nonmetal‐to‐metal ‐ring coordination. The unexpected coordination, which is distinctly different from the typical organoring‐to‐metal coordination in half‐sandwich‐type organometallic compounds, contributes to the ambient stability of the as‐obtained single‐atom‐layered nanocluster as revealed through theoretical and experimental analyses. Furthermore, quantum chemical calculations revealed dominant electron transition along the horizontal x‐direction of the Pd8 plane, indicating high photothermal conversion efficiency (PCE) of the nanocluster, which was verified by the experimental PCE of 73.3 %. Therefore, this study unveils the birth of a novel type of compound and the finding of the unusual nonmetal‐to‐metal ‐ring coordination and has important implications for future syntheses, structures, properties, and structure–property correlations of single‐atom‐layered metal‐based materials.

Pd8 Nanocluster with Nonmetal-to-Metal- Ring Coordination and Promising Photothermal Conversion Efficiency.

Constructing ambient-stable, single-atom-layered metal-based materials with atomic precision and understanding their underlying stability mechanisms are challenging. Here, stable single-atom-layered nanoclusters of Pd were synthesized and precisely characterized through electrospray ionization mass spectrometry and single-crystal X-ray crystallography. A pseudo-pentalene-like Pd8 unit was found in the nanocluster, interacting with two syn PPh units through nonmetal-to-metal -ring coordination. The unexpected coordination, which is distinctly different from the typical organoring-to-metal coordination in half-sandwich-type organometallic compounds, contributes to the ambient stability of the as-obtained single-atom-layered nanocluster as revealed through theoretical and experimental analyses. Furthermore, quantum chemical calculations revealed dominant electron transition along the horizontal x-direction of the Pd8 plane, indicating high photothermal conversion efficiency (PCE) of the nanocluster, which was verified by the experimental PCE of 73.3 %. Therefore, this study unveils the birth of a novel type of compound and the finding of the unusual nonmetal-to-metal -ring coordination and has important implications for future syntheses, structures, properties, and structure-property correlations of single-atom-layered metal-based materials.

Alkali metals doping into open-cage fullerenes: Novel alkalides (M+@C50N5H5)Mʹ− with large nonlinear optical responses

Based on open-cage fullerenes C50N5H5, a novel type of compounds (M+@C50N5H5)Mʹ− (M = Li, Na; Mʹ = Li, Na and K) was designed and studied. Firstly, their alkalides’ properties are confirmed by their FMO and NPA charges analysis. In particular, the proposed alkalides exhibited considerable first hyperpolarizability (β0) up to 1.91 × 105 a.u., which indicated that they could be regarded as high-performance novel NLO molecules. These alkalides will pave the way for further exploration of electronic-stable, high-performance NLO materials.

Discovery of novel heterocyclic derivatives as potential glycogen phosphorylase inhibitors with a cardioprotective effect

The purpose of this study was to evaluate the effect of GP inhibitor as a potential pharmaceutical target on MI/R injury. Four different structural types of novel compounds (I, II, III, and IV) were designed and synthesized, obtaining 31 novel GP inhibitors. SAR studies revealed that the conjugates of 5-chloroindole with benzo six-membered heterocyclic were found to elevate the activity. In particular, compound IIIh (IC50 = 0.21 ± 0.03 µM) emerged as a potent derivative against RMGPa, being approximately 2-fold less potent than that of PSN-357. In order to screen out a compound for in vivo activity test, we further conducted an experiment of inhibition against three different subtypes of GPa (HLGPa, HMGPa and HBGPa) and the corresponding affinity experiment. As a result, compound IIIh showed strong inhibitory activity against the above three subtypes of GP, especially on HBGPa (IC50 = 0.09 ± 0.002 µM), which was relatively close to that of positive control ingliforib (IC50 = 0.16 ± 0.02 µM). The affinity of compound IIIh to HBGPa was 4.3 times higher than that of HLGPa, and 1.1 times higher than that of HMGPa. This fact further proved that compound IIIh has a higher inhibitory effect on HMGPa than the other two subtypes. Besides, in vivo activity evaluation demonstrated that compound IIIh exhibited obviously cardioprotective effect on MI/R injury mice. The discovery of compound IIIh provides a new strategy for developing novel GP inhibitors with myocardial ischemia protection.

High-rate synthesis of SiCN films using single-source silicon precursor with high-density helicon plasma

A novel type of compound, namely Si-guanidinate, where the Si center of alkylsilyl is linked with pyrrolyl-guanidinate ligand, has been synthesized as potential chemical vapor deposition (CVD) precursor and characterized by 1H, 13C, EI-MS, and elemental analysis. The thermal properties of the Si-guanidinate, including vapor pressure and thermal stabilities which were investigated by simultaneous thermal analyses (STA) exhibit a promising precursor in CVD process. The Si-guanidinate was used as a single-source liquid organosilicone precursor to deposit silicon carbon nitride (SiCN) films with the helicon plasma-enhanced chemical vapor deposition (HWP-CVD) method. The effect of the substrate pules negative bias voltage (-Vs) on the microstructure, morphology, composition and optical properties (including refractive index) of the SiCN films has been studied. The deposition rate of the films exhibits a maximum of 15.3 μm/min, which is contributed by the high-density plasma generation of HWP. By X-ray photoelectron spectroscopy (XPS) analysis, the film is mainly composed of Si–C–N. The SiCN films deposited at -VS of 1500 V appear to be high N content of 30.0% (k = 1.83) materials with quite small surface roughness (Root mean square (RMS)~0.7 nm).

Syntheses of Bis(N-heterocyclic carbene)s and their application in main-group chemistry

Since the first isolation of an N-heterocyclic carbene (NHC) in the early 1990s, these species have been identified as valuable tools for the stabilization of main-group elements in unusual oxidation states and allowed for the isolation of novel types of compounds. While bis(NHC)s, i.e., compounds in which two NHC units are framed within one molecule by using suitable linker groups, found numerous application in rare-earth and transition-metal chemistry, this does not hold true for main-group elements. Although examples are found throughout the s- and p-block, their potential still needs to be realized. This review summarizes the syntheses of the related bis(NHC)s and gives an overview of mono-, di- and polynuclear complexes incorporating main-group elements and bis(NHC)s.

Types of novel compounds in Danish

Types of novel compounds in Danish

Stimuli-responsive organic chromic materials with near-infrared emission

Organic chromic materials that respond to external stimuli, especially in the solid state, have sparked extensive interest owing to their potential use as smart materials. In particular, the availability of chromic materials, which emit fluorescence or phosphorescence in the deep penetrating, near-infrared (NIR) region, has led to great improvements in imaging. Various methods that were commonly applied to construct chromic materials, have been reformed to develop the novel type of compounds, and some have received rewards with excellent fingdings. Relevant research achievements of practical applications have showed their potential with the changes that locate in the NIR region, while further in-depth explorations about the inherent chromic chromism are underway. In this review, several representative studies, which have led the development of responsive organic chromic materials with near-infrared emission, will be discussed.

NHCs in Main Group Chemistry

Since the discovery of the first stable N-heterocyclic carbene (NHC) in the beginning of the 1990s, these divalent carbon species have become a common and available class of compounds, which have found numerous applications in academic and industrial research. Their important role as two-electron donor ligands, especially in transition metal chemistry and catalysis, is difficult to overestimate. In the past decade, there has been tremendous research attention given to the chemistry of low-coordinate main group element compounds. Significant progress has been achieved in stabilization and isolation of such species as Lewis acid/base adducts with highly tunable NHC ligands. This has allowed investigation of numerous novel types of compounds with unique electronic structures and opened new opportunities in the rational design of novel organic catalysts and materials. This Review gives a general overview of this research, basic synthetic approaches, key features of NHC-main group element adducts, and might be useful for the broad research community.

On-line comprehensive two-dimensional liquid chromatography tandem mass spectrometry for the analysis of Curcuma kwangsiensis

A novel online comprehensive two-dimensional liquid chromatography (2DLC) coupled with quadrupole time-of-flight (Q-TOF) mass spectrometry (MS) method is developed for the analysis of Curcuma kwangsiensis (C. kwangsiensis) extract. In this system, a newly developed phenyl/tetrazole sulfoether (PTAS) bonded stationary phase was introduced to construct RPLC×RPLC combined with C18. The unique structure endowed PTAS with very different selectivity from C18, reaching a high orthogonality of 93.2%. Moreover, such a combination settled compatibility issues because of the weaker hydrophobic retaining property of PTAS, thus allowing direct interfacing in online configuration. As a result of coupling with the mass spectrometry, a four-dimensional (4D) data plot was presented, in which 439 peaks (containing positive mode and negative mode) were counted, and 105 compounds were grouped and tentatively identified in C. kwangsiensis extract, including 73 unreported ones. Some novel types of compounds with masses exceeding 500 were discovered for the first time. Besides, compared to one-dimensional liquid chromatography (1DLC), the great resolution power of this system allowed separation of more isomers. These results provide supplementary to the material basis of C. Kwangsiensis and in-depth research should be conducted. The configuration of RPLC×RPLC-Q-TOF MS can be a powerful and efficient tool for separation and characterization of chemical substances in complicated herbal extracts.

Synthesis and evaluation of the antitumor activity of highly functionalised pyridin-2-ones and pyrimidin-4-ones

The methods for selective synthesis of two novel types of compounds including pyridin-2-ones 3 and pyrimidin-4-ones 4 were developed. The antitumor bioactivity screening showed that certain compounds had potent antitumor activity.

Antifungal activity of 1′-homo-N-1,2,3-triazol-bicyclic carbonucleosides: A novel type of compound afforded by azide-enolate (3+2) cycloaddition

The first report of 1′-homo-N-1,2,3-triazol-bicyclic carbonucleosides (7a and 7b) is described herein. Azide-enolate (3+2) cycloaddition afforded the synthesis of this novel type of compound. Antifungal activity was evaluated in vitro against four filamentous fungi (Aspergillus fumigatus, Trichosporon cutaneum, Rhizopus oryzae and Mucor hiemalis) as well as nine species of Candida spp. as yeast specimens. These pre-clinical studies suggest that compounds 7a and 7b are promising candidates for complementary biological studies due to their good activity against Candida spp.

Prediction of carbon dioxide solubility in ionic liquids using MLP and radial basis function (RBF) neural networks

Elimination of carbon dioxide from gas mixtures is a common commercial step in natural gas refineries. Nowadays, room-temperature ionic liquids, which are a relatively novel type of compounds have gained attention in recent years and have potential to be considered as a substitution for conventional volatile organic solvents in reaction and separation processes. No flammability, high thermal stability, a wide liquid range, and electric conductivity are some properties of ILs, which make them interesting more and more.Information about the solubility and the rate of solubility is a crucial factor for consideration of ILs for potential industrial processes. Because of some difficulties associated with experimental measurements and expenses spent on ILs, developing predictive methods for prognostication of the phase behavior of such types of systems are more favorable. Thermodynamic models are relatively complex and require complicated mathematical operations.Due to such difficulties there is a need to develop general models capable to predict phase behavior of systems such as CO2 with various kinds of ILs. In this study, four different methods based on artificial intelligence are proposed to predict CO2 solubility in different ionic liquids. The results showed that the predicted values are in great agreement with the experimental data and the maximum absolute error deviation for the best predictor is no more than 3.5%. A comparison between developed models and previously published ones reveals the superiority of the proposed models in this study.

Synthesis and anticancer activity evaluation of 2(4-alkoxyphenyl)cyclopropyl hydrazides and triazolo phthalazines

A series of new 2(4-alkoxyphenyl)cyclopropyl hydrazide- and triazolo-derivatives were synthesized starting from 4-hydroxycinnamic acid (1) in a clean, mild, efficient and straightforward synthetic protocol. These compounds consisting of different alkoxy substitution, phenylcyclopropyl backbone and different heterocyclic groups were evaluated for in vitro anticancer activity against 4 cell lines displaying certain levels of resistance to pro-apoptotic stimuli and 2 cell lines sensitive to pro-apoptotic compounds. Compounds 7f and 8e were most active and displaying moderate in vitro cytostatic effect through different mechanisms. Significantly, chemically modified derivatives could be obtained in order to develop novel types of compounds aiming to combat apoptosis-resistant cancers, for example, those cancers associated with dismal prognoses.

Inhibitors of Protein Geranylgeranyltransferase I and Rab Geranylgeranyltransferase Identified from a Library of Allenoate-derived Compounds

Protein geranylgeranylation is critical for the function of a number of proteins such as RhoA, Rac, and Rab. Protein geranylgeranyltransferase I (GGTase-I) and Rab geranylgeranyltransferase (RabGGTase) catalyze these modifications. In this work, we first describe the identification and characterization of small molecule inhibitors of GGTase-I (GGTI) with two novel scaffolds from a library consisting of allenoate-derived compounds. These compounds exhibit specific inhibition of GGTase-I and act by competing with a substrate protein. Derivatization of a carboxylic acid emanating from the core ring of one of the GGTI compounds dramatically improves their cellular activity. The improved GGTI compounds inhibit proliferation of a variety of human cancer cell lines and cause G(1) cell cycle arrest and induction of p21(CIP1/WAF1). We also report the identification of novel small molecule inhibitors of RabGGTase. These compounds were identified first by screening our GGTI compounds for those that also exhibited RabGGTase inhibition. This led to the discovery of a common structural feature for RabGGTase inhibitors: the presence of a characteristic six-atom aliphatic tail attached to the penta-substituted pyrrolidine core. Further screening led to the identification of compounds with preferential inhibition of RabGGTase. These compounds inhibit RabGGTase activity by competing with the substrate protein. These novel compounds may provide valuable reagents to study protein geranylgeranylation.

Novel Beltlike and Tubular Structures of Boron and Carbon Clusters Containing the Planar Tetracoordinate Carbon: A Theoretical Study of (C3B2)nH4 (n = 2−6) and (C3B2)n (n = 4−8)

By use of the most stable structure of C3B2H4 as a basic block, we construct two types of novel compounds containing the planar tetracoordinate carbon (ptC), beltlike compounds (C3B2)nH4 (n = 2−6) and tubular compounds (C3B2)n (n = 4−8). Equilibrium geometries, vibrational frequencies, and electronic spectra of both series of compounds have been determined by the density functional theory. The results reveal that the same direction arrangement of C2CB2 units with ptC will result in the most stable isomers of (C3B2)nH4 (n = 2−6). Predicted nucleus-independent chemical shift values show that the three-membered rings have aromaticity, whereas the six-membered rings have antiaromaticity. Calculations show that these compounds containing ptC atoms exhibit remarkable size dependence of their highest-occupied molecular orbital−lowest-unoccupied molecular orbital energy gaps and the first excitation energies.

Characterization of a Byproduct in the Alkylation of DMIT: Alkylation on the Least Nucleophilic Sulfur Atom

AbstractIt is generally accepted that the alkylation of (Et4N)2[Zn(DMIT)2] (1) is a very clean reaction that produces 4,5‐bis(alkylthio)‐1,3‐dithiole‐2‐thiones 4 in very high yields. Although this procedure has been widely used, we have found that, in addition to the 4,5‐bis(alkylthio)‐1,3‐dithiole‐2‐thione products 4, highly unexpected byproducts are formed during the alkylation reaction in which the thione functionalities of DMIT in (Et4N)2[Zn(DMIT)2] (1) are alkylated instead of the more reactive thiolate groups. These byproducts were identified as a novel type of compounds, namely bis(2‐alkylthio‐1,3‐dithiol‐1‐ium‐4,5‐dithiolato)zinc compounds 3, being composed of two identical 2‐alkylthio‐1,3‐dithiol‐1‐ium‐4,5‐dithiolate moieties coordinated to a single zinc(II) atom and were characterized by elemental analyses and different spectroscopic techniques as well as single‐crystal X‐ray structure analyses. A comparison of the physical properties of compounds 3 and (Et4N)2[Zn(DMIT)2] (1) has been carried out. The outcome of these investigations revealed significant differences in the physical properties of these two systems. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Resorcarenes: Hollow Building Blocks for the Host-Guest Chemistry

The continuous search for new qualities and the desirability of controlling the size, shape and the chemical features had led to the successful synthesis of various molecular containers and their complexes starting from resorcarene skeleton. The rigidified cavitands have been extended to capture in their round hug bigger and bigger molecules. By covalent synthesis many kinds of new hosts have been built, that maintain guests in their prison for more and more long time. Self assembly, driven by metal-ligand interaction, van der Waals forces, hydrophobicity and, mainly, hydrogen bonds, is at the base of capsules, a novel type of compounds with a peculiar inner phase, stereochemistry and reactivity. The amazing variety of hollow buildings with a resorcarene-based framework and often unique properties is reviewed. Keywords: ionophores, cyclodextrins, host-guest chemistry, calixarenes, distorted octahedral coordination, co-crystallisation, cavitands, solvent effects, capped porphyrins

Plasma LDL cholesterol lowering by plant phytosterols in a hamster model

A series of new 2(4-alkoxyphenyl)cyclopropyl hydrazide- and triazolo-derivatives were synthesized starting from 4-hydroxycinnamic acid (1) in a clean, mild, efficient and straightforward synthetic protocol. These compounds consisting of different alkoxy substitution, phenylcyclopropyl backbone and different heterocyclic groups were evaluated for in vitro anticancer activity against 4 cell lines displaying certain levels of resistance to pro-apoptotic stimuli and 2 cell lines sensitive to pro-apoptotic compounds. Compounds 7f and 8e were most active and displaying moderate in vitro cytostatic effect through different mechanisms. Significantly, chemically modified derivatives could be obtained in order to develop novel types of compounds aiming to combat apoptosis-resistant cancers, for example, those cancers associated with dismal prognoses.

Virol A, a toxic trans-polyacetylenic alcohol of Cicuta virosa, selectively inhibits the GABA-induced Cl − current in acutely dissociated rat hippocampal CA1 neurons

The effects of virol A (VA), a toxic component of Cicuta virosa (water hemlock), on the GABA-induced Cl − current ( I GABA) in acutely dissociated rat hippocampal CA1 neurons were investigated using whole-cell patch-clamp techniques. VA reversibly reduced I GABA and the muscimol (Mus)-induced current ( I Mus) in a concentration-dependent manner. The IC 50 values for VA against I GABA and I Mus were 9.6×10 −7 and 9.8×10 −7 M, respectively. VA shifted the EC 50 value of I GABA from 6.5×10 −6 to 2.1×10 −5 M, whereas it had no effect on the maximum response, thereby suggesting that VA inhibited I GABA in a competitive manner. VA had no apparent effect on current–voltage relationships for I GABA, thus indicating the lack of voltage-dependency. On the other hand, application of VA (10 −6 M) did not additionally reduce the I GABA suppressed by >10 −5 M picrotoxin. VA but not bicuculline accelerated the decay phase of I GABA, as was seen with picrotoxin. Moreover, pre-application of 10 −5 M VA reduced I GABA. VA did not inhibit that induced by glycine (10 −4 M). These results indicate that VA inhibits I GABA by acting both on the GABA agonist site and on the Cl − channel of the GABA A receptor–channel complex. VA is a structurally novel type of compound that selectively inhibits the GABA A receptor–Cl − channel complexes in mammalian central nervous system neurons.