Compound VI Research Articles

Novel alkyne chromophore of the isophorone derivatives: synthesis, electrochemical evaluation, DFT, and processable bottom contact/top-gate OFET applications

Fused alkyne molecules are important in organic semiconductors due to their desirable properties. Here, we report the design and synthesis of a new series of A–π–D molecules (III–VII) that can serve as mild electron acceptors to generate wide-bandgap p-type small compounds for use in organic field-effect transistors. The incorporation of donor units into fused isophorone frameworks can be used to tune the frontier molecular orbital energies. The electrochemical, optical, and thermal properties of the compounds were characterized. Compound VI, which has a fused phenyl-substituted alkyne moiety, had the highest occupied molecular orbital energy level as determined by optical and electrochemical analysis. Density functional theory calculations revealed that compounds VI and III had lower hole reorganization energy (λh) than the corresponding isophorone extended conjugated-based compounds (I–II). Conversely, compounds I and II had lower electron reorganization energy (λe) than the corresponding fused alkyne compounds. This is in line with the observed adiabatic ionization potential and electron affinity values. Consequently, devices fabricated with compound VI exhibited high mobility and low threshold voltage.

Novel diamide derivatives: Synthesis, characterization, urease inhibition, antioxidant, antibacterial, and molecular docking studies

Novel diamides (I-VI) were synthesized, corroborated by various spectroscopic techniques including IR, 1H NMR, 13C NMR, mass spectrophotometry and elemental analysis. The in vitro screening of the newly synthesized compounds was evaluated for their urease inhibition activity and compound IV was found the most potent derivative with 2.5-fold more enhanced activity (IC50 = 8.17 ± 0.39 mg/mL) than the standard drug thiourea (IC50 = 20.79 ± 0.34 mg/mL). The molecular docking study supported the experimental results and revealed that compound IV has shown a significant dock score and binds within the active site of the target enzyme. Furthermore, these compounds were investigated for their efficacy as antioxidant and antimicrobial agents in vitro. Among all the tested compounds, compound I (IC50 = 45.88±3.99 µg/mL) showed the highest antioxidant activity, whereas compound VI (IC50 = 124.60±2.20 µg/mL) exhibited the lowest activity when compared to standards. Concerning antibacterial activities especially compound III showed superior antimicrobial activity against the bacteria type B. cereus compared to the other compounds. Based on the present research, it was concluded that useful application areas such as the pharmaceutical industry can be investigated by conducting in vivo biochemical tests of effective diamides.

A potent candidate against Zika virus infection: Synthesis, bioactivity, radiolabeling and biodistribution studies

Compound VI exhibits potent activity against Zika virus infection combined with favorable cellular uptake and biodistribution without apparent cytotoxicity in a mouse model.

SYNTHESIS AND BIOLOGICAL EVALUATION OF NOVEL PYRAZOLO[3,4-D]PYRIMIDINE DERIVATIVES OF EXPECTED ANTICANCER ACTIVITY

A series of novel pyrazolo[3,4-d]pyrimidine derivatives have been designed based on chemical modifications on the general features of the reported and clinically used EGFR-TKIs such as repalcing of quinazoline moiety of reported EGFR-TKIs as erlotinib by pyrazolo[3,4-d]pyrimidine nucleus,introducing different hydrophobic moieties including phenyl, aromatic heterocyclic, fused aromatic or aliphatic structures , introducing different linkers which may be one atom , two atoms, three atoms, four atoms and five atoms and introducing of phenyl ring at position-3 of 1H-pyrazolo[3,4-d]pyrimidine nucleus to occupy the hydrophobic region II of ATP binding site. All the new synthesized compounds were biologically screened in vitro for their cytotoxic activities against four cancer cell lines namely, HepG-2, MCF-7, HCT-116, and Hela. The results of cytotoxic evaluation indicated that compound VI was found to be the most prominent broad-spectrum cytotoxic activity and significantly more potent than doxorubicin with IC50 values of 6.18, 6.48, 4.03, and 5.82μM against tested cell lines. In addition, compounds IXa,b displayed promising cytotoxic effect against all tested cell lines with IC50 values less than 30 μM compared with doxorubicin as a control drug. Besides, compound X possessed excellent anti-proliferative activities against the four cell lines with IC50 values ranging from 18 μM to 39.5 μM. Structural pharmacophoric features indicated that pyrazolo[3,4-d]pyrimidine scaffold having a four atoms linker as thiosemicarbazide moiety as compounds IXa,b which substituted with aliphatic moiety at the 4-position was more potent than those possessing one atom, two atoms, three atoms and five atoms linkers which lead to significant decrease in cytotoxic

Pharmacological evaluation and in-silico modeling study of compounds isolated from Ziziphus oxyphylla

Medicines derived from plants are preferred over synthetic therapeutic agents in treating different diseases. Ziziphus oxyphylla (a member of Rhamnaceae family) is a medicinal plant used as a remedy of different diseases in Greek and Ayurveda medical systems. Z. oxyphylla roots were shade dried and then subjected to extraction of bioactive compounds using different solvent systems and silica gel. From ethyl acetate fraction, three compounds viz., p-coumaric acid (V), 3,4-dimethoxy benzoic acid (VI), and 4-heptyloxy benzoic acid (VII) were isolated in pure form. The selection of ethyl acetate fraction for isolation was based on HPLC profiling of crude extract and different fractions. These compounds were characterized by different spectroscopic techniques and evaluated for their in vitro antioxidant, anticholinesterase, α–glucosidase, and α-amylase inhibitory potentials. To find out possible binding interactions of V with AChE and BChE crystals, in-silico docking studies were also carried out. Compound V showed maximum scavenging capabilities of DPPH and ABTS free radicals with IC50 values of 69 and 62 μg/mL respectively. Excellent percent inhibition (83.4 ± 0.5% at highest concentration 1000 μg/mL) of acetylcholinesterase (AChE) was exhibited by compound V (IC50 = 80 μg/mL); whereas, for the mentioned concentration, 83.2 ± 1.1% inhibition (IC50 = 90 μg/mL) of butyrylcholinesterase (BChE) was observed as well. The compound VI exhibited highest % inhibition against α-glucosidase (IC50 = 84 μg/mL) whereas α-amylase was more potently inhibited by compound V (% inhibition = 86.8 % and IC50 = 85 μg/mL). Docking scores of -1.391 Kcal/mol (BChE) and –6.253 Kcal/mol (AChE) were recorded using molecular docking software. Compound V exhibited strong free radical scavenging and anticholinesterase potentials suggesting that it can be effectively used to treat oxidative stress and dementia in human.

µ2-Oxo-Bis[(2,5-Dinitrophenoxo)triarylantimony]: Syntheses, Structures, and Reactions with Pentaarylantimony

Antimony aroxides [Ph3SbOC6H3(NO2)2-2,5]2O (I) and [(4-MeC6H4)3SbOC6H3(NO2)2-2,5]2O (II) were synthesized by the oxidation of triarylantimony with tert-butyl hydroperoxide in the presence of 2,5-dinitrophenol. The SbOSb fragments in compounds I and II are bent (the corresponding angles are 139.70(10)° and 142.32(12)°). The Sb−Оbr bonds (1.973(3), 1.980(3) A in I; 1.975(2), 1.977(2) A in II) are substantially shorter than Sb−Ot (2.211(3), 2.213(3) and 2.191(2), 2.191(2) A in I and II, respectively). Aroxides Ar4SbOC6H3(NO2)2-2,5 (Ar = Ph (III) and 4-MeC6H4 (IV)) and carbonates (Ar4Sb)2CO3 (Ar = Ph (V) and 4-MeC6H4 (VI)) are formed from Ar5Sb and compounds I and II in the presence of oxygen and carbon dioxide, respectively. In the trigonal bipyramidal molecules of compounds III and IV, the СSbO axial angles are 175.80(7)° and 176.86(10)° (Sb−O 2.290(2) and 2.342(2) A, respectively). One of the antimony atoms in compound V and in crystallographically independent molecules of two types of compound VI is pentacoordinated (the Sb−Oax bond is 2.245(6) A in V and is 2.263(3) and 2.263(3) A in VIа and VIb, respectively), whereas the second antimony atom is hexacoordinated (Sb−O 2.249(6) and 2.273(5) A in V; 2.216(2), 2.251(2) A and 2.217(2), 2.251(2) A in VIа and VIb). The crystallographic data are deposited with the Cambridge Crystallographic Data Centre (СIF files ССDС nos. 1890704 (I), 1890706 (II), 1890713 (III), 1890714 (IV), 994519 (V), and 994177 (VI)).

Design, synthesis, and in vitro evaluation of novel 1,3,4-oxadiazolecarbamothioate derivatives of Rivastigmine as selective inhibitors of BuChE

Rivastigmine has been prescribed for the therapy of Alzheimer’s disease (AD) symptoms. This drug is classified in the carbamate derivative group that has dual activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). According to the structure of Rivastigmine and its performance, a new series of 5-aryl-1,3,4-oxadiazole-2-carbamothioate compounds I–XI was synthesized using structure-based drug discovery approaches. For this purpose a set of these compounds were designed with computational docking method and their interactions with amino acid residues in the active sites of AChE and BuChE checked out. The structures of synthesized compounds were established by physicochemical and spectroscopic methods. The carbamoyl moiety of Rivastigmine structure was modified to carbamothioate and the effects of 1,3,4-oxadiazole heterocycle as a pharmacophoric nucleus were investigated. The potential of the synthesized compounds I–XI was evaluated against two most known agents of AD (AChE and BuChE) to determine their IC50 values. The results of the docking showed the range of binding affinity for the best poses of ten individual conformers for any compounds (I–XI) was between −7.81 (VI) and −6.75 (II) kcal/mol. The results of biological experiments displayed that most synthetic compounds (I–VIII) showed moderate to excellent selective activity range against BuChE (0.51–69.44 µM). In vitro cytotoxicity evaluation of these compounds (I–XI) by MTT assay on human dermal fibroblast (HDF) cell line exhibited no activity against HDF. The compound VI [S-(5-(p-tolyl)-1,3,4-oxadiazol-2-yl) ethyl(methyl)carbamothioate] showed the most stable binding affinity (−7.81 kcal/mol) and the lowest IC50 value (0.51 µM) in comparison with Rivastigmine with 7.72 µM and Donepezil with 5.20 µM against BuChE.

<p>Isolation, pharmacological evaluation and molecular docking studies of bioactive compounds from Grewia optiva</p>

BackgroundTraditionally, Grewia optiva is widely used for the treatment of many diseases like dysentery, fever, typhoid, diarrhea, eczema, smallpox, malaria and cough.MethodsShade-dried roots of G. optiva were extracted with methanol. Based on HPLC results, chloroform and ethyl acetate fractions were subjected to silica column isolation and four compounds: glutaric acid (V), 3,5 dihydroxy phenyl acrylic acid (VI), (2,5 dihydroxy phenyl) 3',6',8'-trihydroxyl-4H chromen-4'-one (VII) and hexanedioic acid (VIII) were isolated in pure form. Ellman’s assay was used to determine the anticholinesterase potential of isolated compounds while their antioxidant potential was estimated by DPPH and ABTS scavenging assays.ResultsAmongst the isolated compounds, VI and VII exhibited excellent percent inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) (83.23±1.11, 82.72±2.20 and 82.11±2.11, 82.23±1.21, respectively, at 1000 µg/mL) with IC50 of 76, 90, 78 and 92 µg/mL, respectively. Highest percent radicals scavenging against DPPH and ABTS (87.41±1.20 and 86.13±2.31) with IC50 of 64 and 65 µg/mL, respectively, were observed for compound VII. Molecular docking studies also supported the binding of compound VI and VII with the target enzyme. The para-hydroxyl group of the phenolic moiety is formed hydrogen bonds with the active site water molecule and the side chain carbonyl and hydroxyl residues of enzyme.ConclusionThe isolated compounds inhibited the DPPH and ABTS-free radicals, and AChE and BChE enzymes. It was concluded that these compounds could be used in relieving the oxidative stress and pathological symptoms associated with excessive hydrolysis of acetyl and butyryl choline. The results of the study were supported by docking studies for compounds VI and VII.

The Synthesis and Preliminary Anticancer Evaluation of 6-Mercaptopurine -Methotrexate Conjugate as Possible Mutual Prodrug

Small molecules drug conjugate mutual prodrug design (SMDC) composed of folate &lethal agent conjugate , rigidly bonded via hydrophilic bridge& self immolative disulfide bond ; represent new interesting approaches for cancer treatment , the component of SMDC intended to be as possible suit targeted folate receptor , along with greater conservation of component until reaching targeting tumor tissue . The designing & synthesis of compound VI & IIX derived from 6-MP & MTX conjugate altogether as mutual prodrug were processed forward successfully by multiple steps procedure , and by TLC spectrophotometry preliminary analysis assess in detection of products & their intermediate , along with their purity . The structure of two final compounds & their intermediate were proclaimed by melting point measurement , infrared spectrometry & HNMR analysis given results greatly correspond with theoretical proposed chemical structure of synthesized compounds . Furthermore anticancer evaluation on cell line level had been done for two final compound against MCF-7& SKO-3 types of cancer cell & the result were confirmed which show greater cytotoxic tumor activity of two final compound ,while compound IIX possess optimal activity proportional with increase number of 6-MP residue .

Synthesis and Preliminary Anticancer Evaluation of 6-Mercaptopurine –Methotrexate Conjugate as Possible Mutual Prodrug

Small molecules drug conjugate mutual prodrug design (SMDC) composed of folate and lethal agent conjugate, rigidly bonded via hydrophilic bridge and self immolative disulfide bond ; represent new interesting approaches for cancer treatment , the component of SMDC intended for targeting folate receptor , along with greater conservation of component until reaching the target tumor tissue . The designing and synthesis of compound VI and VIII derived from 6-Mercaptopurine (6-MP) and Methotrexate ( MTX) conjugate altogether as mutual prodrugs were processed forward successfully by multistep reaction procedures , and by Thin Layer Chromatography (TLC) for preliminary detection of products and their intermediates, along with their purity. The structures of two final compounds and their intermediates were proclaimed by melting point measurement, infrared spectrometry and ¹HNMR analysis given results greatly correspond with theoretical proposed chemical structure of synthesized compounds. Furthermore, cytotoxic activity evaluation on cell line level had been done for two final compounds against human breast tumor cell (MCF-7) and human ovarian tumor cell (SKO-3) types of cancer cell line and the results were confirmed which show greater cytotoxic tumor activity of two final compounds, while compound VI possess optimal activity proportional with increased number of 6-MP molecules.

Synthesis and Pharmacological Screening of Pyridopyrimidines as Effective Anti-Diarrheal Agents through the Suppression of Cyclic Nucleotide Accumulation.

The increased levels of cyclic nucleotides (cGMP and cAMP) in enterocytes trigger intracellular mechanisms of ion and fluid secretion into the lumen, causing secretory diarrhea. Twelve novel pyridopyrimidines derived from 5‐(3,5‐bistrifluoromethylphenyl)‐1,3‐dimethyl‐5,11‐dihydro‐1H‐indeno[2,1 : 5,6]pyrido[2,3‐d]pyrimidine‐2,4,6‐trione (FPIPP) were synthesized and evaluated on intracellular cyclic nucleotide accumulation. All compounds had no effect on either cyclic nucleotide basal levels or on pre‐contracted aortic rings. The metabolic activity and viability in T84 cells, assessed by MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide) and the LDH (lactate dehydrogenase) assays, respectively, were not affected by incubation with the compounds (50 μM). Compound VI almost abolished cGMP accumulation (94 % inhibition) induced by STa toxin in T834 cells and significantly reduced (69 %) forskolin‐induced cAMP accumulation in Jurkat cells. Compound VI was active in an in vivo model for diarrhea in rabbits. These results prompted us to perform a microscopic histopathological analysis of intestinal tissues, showing that only compound VI preserves the intestine without significant pathological changes and with a decreased inflammatory pattern in comparison to FPIPP. In vitro stability test revealed that compound VI is resistant to oxidation promoted by atmospheric oxygen.

New perspectives for pharmacological chaperoning treatment in methylmalonic aciduria cblB type

Methylmalonic aciduria cblB type (MMA cblB) is caused by the impairment of ATP:cob(I)alamin adenosyltransferase (ATR), the enzyme responsible for the synthesis of adenosylcobalamin (AdoCbl) from cob(I)alamin. No definitive treatment is available for patients with this condition and novel therapeutic strategies are therefore much needed. Recently, we described a proof-of-concept regarding the use of pharmacological chaperones as a treatment. This work describes the effect of two potential pharmacological chaperones - compound V (N-{[(4-chlorophenyl)carbamothioyl]amino}-2-phenylacetamide) and compound VI (4-(4-(4-fluorophenyl)-5-methyl-1H-pyrazol-3-yl)benzene-1,3-diol) - on six ATR mutants, including the most common, p.Arg186Trp. Comprehensive functional analysis identified destabilizing (p.Arg186Gln, p.Arg190Cys, p.Arg190His, p.Arg191Gln and p.Glu193Lys) and oligomerization (p.Arg186Trp and p.Arg191Gln) mutations. In a cellular model overexpressing the destabilizing/oligomerization mutations, compounds V and VI had a positive effect on the stability and activity of all ATR variants. When provided in combination with hydroxocobalamin a more positive effect was obtained than with the compounds alone, even in mutations previously described as B12 non-responsive. In addition, a normal oligomerization profile was recovered after treatment of the p.Arg186Trp mutant with both compounds. These promising results confirm MMA cblB type as a conformational disorder and hence, pharmacological chaperones as a new therapeutic option alone or in combination with hydroxocobalamin for many patients with MMA cblB.

Synthesis and Evaluation of Some Dibromoquinazoline-sulphonamide Hybrids and some Schiff´s Base Analogs for their Cytotoxic Activity.

Cancer is one of the most dangerous diseases with quite a high mortality rate. Many quinazoline derivatives show potent anticancer activity. In this work our aim is to develop novel, safe and effective anticancer agents. New 6,8-dibromo-2-(4-chlorophenyl)-quinazoline-sulphonamide hybrids and some Schiff´s base analogs were synthesized, and their structures were confirmed by spectral and elemental analysis. Cytotoxicity of all synthesized compounds was evaluated on three cancer cell lines MCF7, HCT116 and HEPG2 using sulpharodamine- B assay method and doxorubicin as a reference drug. All tested compounds show promising cytotoxic activities on the three cell lines. Compound IXd was 2 times more active than doxorubicin on MCF7 cancer cells, while it was 3 times more potent than doxorubicin on HCT116 cancer cells. Compound IV was 2 times more active than doxorubicin while compound VI exhibited similar activity to doxorubicin on HEPG2 cell line. The most active compounds were tested against epidermal growth factor receptor tyrosine kinase (EGFR TK). Compounds IV, IXd, IXf show the most potent inhibitory percent 62.3, 91.1, 91.6 respectively. Compounds IV, V, VII, IXd, IXf caused a significant increase of CASP3 activity with range 86.5-37.6 %. The present work led to the discovery of new cytotoxic compounds having quinazoline pharmacophore.

Synthesis of New 7-bromo-5-(2’-chlorophenyl)-3-arylamino-1,2-dihydro-3H-1,4-benzodiazepine Derivatives and Their Influence on Appetite in Rats

A series of new 7-bromo-5-(2′-chlorophenyl)-3-arylamino-1,2-dihydro-3H-1,4-benzodiazepine derivatives (II-VIII) were synthesized. The series of synthesized compounds included those that had a substantial effect on appetite in rats, exhibiting both orexigenic and anorexigenic effects at low doses (2.07 – 2.21 μM). Compound VI had anorexigenic activity comparable with that of the hormone leptin, which reduces the appetite and food intake. Co-administration of leptin and III, which exhibited a pronounced orexigenic effect, reduced appetite by 73%.

Синтез новых производных 7-бром-5-(2’-хлор)фенил-3-ариламино-1,2-дигидро-3<i>H</i>-1,4-бенздиазепин-2-онов и их влияние на аппетит крыс

Синтезированы новые производные 7-бром-5-(2’-хлор)фенил-3-ариламино-1,2-дигидро-3H-1,4-бенздиазепина (II – VIII). В ряду синтезированных соединений обнаружены вещества, которые в низких дозах (2,07 – 2,21 мкМ) оказывали существенное влияние на аппетит крыс, проявляя как орексигенное, так и анорексигенное действие. Обнаружено соединение VI, которое по анорексигенному действию не уступает гормону лептину, снижающему аппетит и потребление пищи. При сочетанном введении лептина с соединением III, проявляющим выраженный орексигенный эффект, отмечается снижение аппетита на 73 %.

Benzoquinone from Fusarium pigment inhibits the proliferation of estrogen receptor-positive MCF-7 cells through the NF-κB pathway via estrogen receptor signaling

Natural pigments are known for possessing a wide range of pharmacological and health-promoting properties. The pigments, produced by a new strain Fusarium (Fusarium sp. JN158) previously identified in our laboratory, were found to have 6 peaks (representing 6 compounds) by high-performance liquid chromatography with a diode-array detector (HPLC-DAD) separation. The 6th peak compound (compound VI) is a benzoquinone compound. In this study, we examined the effects of compound VI on the proliferation of breast cancer cells and aimed to elucidate the underlying mechamisms. Compound VI exerted anti-proliferative effects on MCF-7 estrogen receptor (ER)+ cells in a dose-dependent manner (IC25, 7 µM; IC50, 11 µM), whereas it had no effect on MDA-MB-231 ER− cells and normal cells. The cell index (CI) began to decrease at 24 h following treatment with benzoquinone. Mechanistically, the results from molecular analysis revealed that compound VI inhibited the expression of ERα, progesterone receptor (PR), vascular endothelial growth factor (VEGF), Bcl-2, cyclin D1 and nuclear factor-κB (NF-κB) p65, while it increased the expression of cleaved caspase-3 and Bax in the MCF-7 cells. Taken together, our findings indicate that compound VI exerts anti-proliferative effects on MCF-7 cells through the NF-κB pathway via the regulation of ER signaling. Our data may indicate that benzoquinone from Fusarium pigment may have potential for use as an anti-proliferative agent in the treatment of breast cancer.

Schiff Bases of Benzothiazol-2-ylamine and Thiazolo[5,4-b] pyridin-2-ylamine as Anticonvulsants: Synthesis, Characterization and Toxicity Profiling.

Schiff bases have a broad spectrum of biological activities like antiinflammatory, analgesic, antimicrobial, anticonvulsant, antitubercular, anticancer, antioxidant, anthelmintic and so forth. Thus, after a thorough perusal of literature, it was decided to conjugate benzothiazol-2-ylamine/thiazolo [5, 4-b] pyridin-2-ylamine with aromatic and heteroaromatic aldehydes to get a series of Schiff bases. Synthesis, characterization, in-silico toxicity profiling and anticonvulsant activity of the Schiff bases of Benzothiazol-2-ylamine and Thiazolo [5, 4-b] pyridin-2-ylamine. Aniline/4-aminopyridine was converted to the corresponding thiourea derivatives, which were cyclized to obtain benzothiazol-2-ylamine/thiazolo [5, 4-b] pyridin-2-ylamine. Finally, these were condensed with various aromatic and heteroaromatic aldehydes to obtain Schiff bases of benzothiazol-2-ylamine and thiazolo [5, 4-b] pyridin-2-ylamine. The synthesized compounds were characterized and screened for their anticonvulsant activity using maximal electroshock (MES) test and isoniazid (INH) induced convulsions test. In-silico toxicity profiling of all the synthesized compounds was done through "Lazar" and "Osiris" properties explorer. Majority of the compounds were more potent against MES induced convulsions than INH induced convulsions. Schiff bases of benzothiazol-2-ylamine were more effective than thiazolo [5, 4-b] pyridin-2-ylamine against MES induced convulsions. The compound benzothiazol-2-yl-(1H-indol-2-ylmethylene)-amine (VI) was the most potent member of the series against both types of convulsions. Compound VI exhibited the most significant activity profile in both the models. The compounds did not exhibit any carcinogenicity or acute toxicity in the in-silico studies. Thus, it may be concluded that the Schiff bases of benzothiazol-2-ylamine exhibit the potential to be promising and non-toxic anticonvulsant agents.

Alkali-metal thiogermanates: sodium channels and variations on the La3CuSiS7 structure type.

Five new isotypic quaternary chalcogenides containing rare-earth metal atoms crystallizing in the hexagonal noncentrosymmetric space group P6(3) (No. 173) with the La(3)CuSiS(7) structure type have been synthesized by reacting the appropriate anhydrous rare-earth trichloride with sodium thiogermanate, Na(2)GeS(3). The reaction between LnCl(3) and Na(2)GeS(3) in an evacuated fused-silica ampule produced high yields of good-quality crystals of NaLn(3)GeS(7) [Ln = Ce (I), Nd (II), Sm (III), Gd (IV), and Yb (V)], while a similar reaction between EuCl(3) and Na(2)GeS(3) yielded a quinary chloride thiogermanate, Na(1.2)Eu(3.4)Cl(2)Ge(3)S(9) (VI), incorporating a cyclic trimeric Ge(3)S(9) building unit and adopting a structure related to La(3)CuSiS(7). The crystal structure of the compounds comprises a complex network of bicapped trigonal-prismatic LnS(8) and GeS(4) tetrahedra, which creates channels along the [001] direction. The Na(+) cations reside in these channels within trigonally distorted octahedral coordination environments, surrounded by six S atoms. For compounds III-V, the temperature dependence of the magnetic susceptibility indicates that these compounds are paramagnetic with μ(eff). = 1.86, 8.01, and 3.87 μ(B), for III-V, respectively. The experimental μ(eff) for IV is close to the theoretical value of 7.94 for free Gd(3+) ions, while μ(eff) values for III and V deviate from their theoretical values of 0.86 and 4.54 μ(B) for Sm(3+) and Yb(3+) ions, respectively. These compounds are semiconductors with optical band gaps of around 1.3 eV for III and V. Extended Hückel calculations suggest that the valence band comprises primarily S 3p and the bottom of the conduction band is dominated by empty rare-earth 5d orbitals. Compound VI exhibits a sharp optical absorption of around 2.18 eV, which is attributed to the f → d transition of Eu(II). The effective magnetic moment of 7.94 μ(B)/Eu is in excellent agreement with the theoretical value of 7.94 μ(B) for the free Eu(2+) ion.

Dicarbonylcyclopentadienyltellurophenyliron complexes as ligands

The reaction of CpFe(CO)2TePh (I) with ferricinium hexafluorophosphate as an oxidant affords ionic complex {[CpFe(CO)2]2(μ-TePh)}+PF6− (II) with the simultaneous formation of diphenylditellurium. The decarbonylation of compound II by Me3NO followed by the addition of complex I affords trinuclear complex {[CpFe(CO)2(μ-TePh)]2Fe(CO)Cp}PF6 (III). The corresponding tetrafluoroborate (IV) is synthesized similarly. The heating of compound I with PPh3 gives CpFe(CO)(PPh3)TePh (V) that reacts with ionic complex [CpMn(CO)2(NO)]PF6 (VI) to form binuclear heterometallic ionic complex [CpFe(CO)(PPh3)(μ-TePh)Mn(CO)(NO)Cp]PF6 (VII). A similar reaction of Cp′Fe(CO)2TePh (Cp′ is methylcyclopentadienyl) with compound VI affords heterometallic [Cp′Fe(CO)2(μ-TePh)Mn(CO)(NO)Cp]PF6 (VIII). The structures of compounds II, IV, VII, and VIII are determined by X-ray diffraction analysis (CIF files CCDC 963285, 963286, 963288, and 963289, respectively).

Chiral separation of six tetralone derivative enantiomers using immobilized cellulose chiral stationary phase

A high performance liquid chromatographic method (HPLC) was developed for the chiral separation of six α-aryl tetralone derivatives, using a Chiralpak IC column. The factors influencing the chiral separation including the type and concentration of organic modifier, column temperature and flow rate were investigated. The results showed that high enantiomeric separation can be obtained with isopropanol as modifier for the six compounds. The thermodynamic study indicated that the enantioseparation was enthalpically driven and showed that low column temperature was beneficial to separation. Complete separation of compound I was achieved with a binary solvent mixture of n-hexane-isopropanol (90 :10, v/v) as the recommended mobile phase. The compounds II , II and IV were separated with the mobile phase of the mixture of n-hexane-isopropanol (99:1, v/v) and the compound V was separated with the mixture of n-hexane-isopropanol (85:15, v/v). The compound VI was separated with the mixture of n-hexane-isopropanol (80:20, v/v). The column temperature was 25 °C, and the flow rate was 1. 0 mL/min. The six tetralone derivative enantiomers were separated on a chiral stationary phase of Chiralpak IC by HPLC. The column has high enantiomeric selectivity to the six tetralone derivative enantiomers.