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2.
ACS Nano ; 13(6): 7091-7099, 2019 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-31145589

RESUMEN

A single-step, direct silicon-substrate growth of black phosphorus (BP) crystals is achieved in a self-contained short-way transport technique under low-pressure conditions (<1.5 MPa). A 115 nm-thick BP hero single crystal is formed with lateral dimensions of 10 × 85 µm. The synthesis proceeds with Sn, SnI4, and red phosphorus and has a well-defined phosphorus phase dependency on the SnI4 concentration. Furthermore, in situ Sn passivation of BP occurs. This allows long-term stability with no sign of any degradation after 4 months of exposure to ambient conditions. Single-crystal BP flakes and multigrain flakes with high- and low-angle grain boundaries are achieved. Electron backscatter diffraction determined crystal growth to be independent of the substrate, which is further supported by successful growth on various substrates, including sapphire, silicon nitride, silicon, and silicon oxide. Cross-sectional transmission electron microscopy of a single crystal flake provides valuable insight into the growth mechanism. Elemental Sn encapsulates BP crystals, and crystalline SnI x inclusions are found to be scattered throughout the BP crystal. It is suggested that SnI x inclusions may provide the dominant mechanism for seeding vertical growth. IR absorption measurements for thin and bulk BP recipes show an equal response below Eg dominated by free carrier absorption. FET devices fabricated from thin-film and bulk BP recipes show improved device performance compared to unpassivated BP films of equal thickness with an on/off current ratio >102.

3.
Spectrochim Acta A Mol Biomol Spectrosc ; 180: 127-137, 2017 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-28284158

RESUMEN

Vanadium(III) tris(dithiocarbonates), [(ROCS2)3V] (R=o-, m-, p-CH3C6H4 and 4-Cl-3-CH3C6H3) and donor stabilized addition complexes [(ROCS2)2V(Cl)·L] [L=NC5H5 or P(C6H5)3] were synthesized and characterized by elemental analyses, IR, mass, TGA/DTA, SEM magnetic susceptibility and heteronuclear NMR (1H, 13C and 31P) spectroscopic studies. The cytotoxicity of the complexes was measured in vitro using the cultivated human cell lines. In addition, the antioxidant activities of the ligands and its vanadium complexes were also investigated through their scavenging effect on DPPH radicals. The antimicrobial activity of ligands and some complexes has been conducted against three bacterial strains and fungus. The density functional theory (DFT) calculations of ligands and vanadium complexes were performed by the DFT/B3LYP/LANL2DZ method to obtain the optimized molecular geometry, vibrational frequencies, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), thermodynamic properties and various other quantum-mechanical parameters.


Asunto(s)
Carbonatos , Compuestos de Azufre , Vanadio , Antiinfecciosos/química , Antiinfecciosos/toxicidad , Bacterias/efectos de los fármacos , Carbonatos/química , Carbonatos/toxicidad , Línea Celular , Supervivencia Celular/efectos de los fármacos , Complejos de Coordinación/síntesis química , Complejos de Coordinación/química , Complejos de Coordinación/toxicidad , Hongos/efectos de los fármacos , Humanos , Espectroscopía de Resonancia Magnética , Compuestos de Azufre/química , Compuestos de Azufre/toxicidad , Termogravimetría , Vanadio/química , Vanadio/toxicidad
4.
Artículo en Inglés | MEDLINE | ID: mdl-25827375

RESUMEN

A new series of donor-stabilized addition complexes of cobalt(II) with disubstituted diphenyldithiophosphates [{(ArO)2PS2}2CoL2] {Ar = 2,4-(CH3)2C6H3 [(1)-(3)] and 3,5-(CH3)2C6H3 [(4)-(6)]; L = C5H5N [(1), (4)], 3,4-(CH3)2C5H3N [(2), (5)] and 4-(C2H5)C5H4N [(3), (6)]} were successfully isolated and characterized by elemental analyses, magnetic moment measurements, IR and single-crystal X-ray analysis. Complexes (3), (4) and (5) crystallize in the monoclinic space groups P2(1)/n, P2(1)/n and P2(1)/c, respectively, whereas complex (6) crystallizes in the triclinic space group P1¯. X-ray diffraction analysis of complexes (3)-(6) reveals a six-coordinated distorted octahedral geometry for the CoS4N2 chromophore defined by two chelating diphenyldithiophosphate anions as well as two N-donor ligands. Two diphenyldithiophosphate ligands are coordinated to the cobalt ion as a bidentate ligand chelating via the two thiolate S atoms. Each of them forms a four-membered chelate ring in the equatorial plane. The N atoms from two donor ligands are axially coordinated to the Co atom in a mutually trans position.

5.
Chempluschem ; 80(3): 583-590, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31973404

RESUMEN

Aromatic organic molecules serve as optoelectronic materials owing to their intrinsic optical and electronic properties. Herein, self-assembled lamellar nanostructures as photoconductor hybrids, which are obtained from naphthalene-2-methoxycarbonyl (Nmoc)-capped peptide amphiphiles, are described. Hybrid nanostructures are constructed in a controlled manner by an electrochemical deposition technique in combination with the inorganic Zn(OH)2 phase. Inorganic Zn(OH)2 layers turn into semiconductor ZnO layers upon annealing at 150 °C and lamellar nanostructures are formed in a periodic manner. Synergistic effects of hydrogen bonding and π-π stacking interactions of aromatic peptide amphiphiles are the driving force for the formation of self-assembled lamellar nanostructures. Morphological, structural, and optical studies of such lamellar hybrid nanostructures are reported. Photoconduction of these hybrid nanostructures is also examined in detail.

6.
Artículo en Inglés | MEDLINE | ID: mdl-25080255

RESUMEN

Donor-stabilized addition complexes of nickel(II) with disubstituted diphenyldithiophosphates, [{(ArO)2PS2}2NiL2] {Ar = 2,4-(CH3)2C6H3 [(1), (5)], 2,5-(CH3)2C6H3 [(2), (6)], 3,4-(CH3)2C6H3 [(3), (7)] and 3,5-(CH3)2C6H3 [(4), (8)]; L = C5H5N [(1)-(4)] and C7H9N [(5)-(8)]}, were successfully isolated and characterized by elemental analysis, magnetic moment, IR spectroscopy and single-crystal X-ray analysis. Compound (4) crystallizes in the monoclinic space group P2(1)/n whereas compounds (7) and (8) crystallize in the triclinic space group P1. The single-crystal X-ray diffraction analysis of (4), (7) and (8) reveals a six-coordinated octahedral geometry for the NiS4N2 chromophore. Two diphenyldithiophosphate ions act as bidentate ligands with their S atoms coordinated to the Ni centre. Each of them forms a four-membered chelate ring in the equatorial plane. The N atoms from two donor ligands are axially coordinated to the Ni atom.

7.
Bioinorg Chem Appl ; 2014: 780631, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24817836

RESUMEN

Lanthanum(III) tris(O-tolyl/benzyldithiocarbonates), [La(ROCS2)] (R = o-, m-, p-CH3C6H4 and C6H5CH2), were isolated as yellow solid by the reaction of LaCl3 ·7H2O with sodium salt of tolyl/benzyldithiocarbonates, ROCS2Na (R = o-, m-, p-CH3C6H4 and C6H5CH2), in methanol under anhydrous conditions in 1 : 3 molar ratio. These complexes have formed adducts with nitrogen and phosphorus donor molecules by straightforward reaction of these complexes with donor ligands, which have the composition of the type [La(ROCS2)3 ·nL] (where n = 2, L = NC5H5 or P(C6H5)3 and n = 1, L = N2C12H8 or N2C10H8). Elemental analyses, mass, IR, TGA, and heteronuclear NMR ((1)H, (13)C and (31)P) spectroscopic studies indicated bidentate mode of bonding by dithiocarbonate ligands leading to hexacoordinated and octacoordinated geometry around the lanthanum atom. Antimicrobial (antifungal and antibacterial) activity of the free ligands and some of the complexes have also been investigated which exhibited significantly more activity for the complexes than the free ligands.

8.
Commun Dis Intell Q Rep ; 38(4): E369-75, 2014 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-25631600

RESUMEN

The Australian Mycobacterium Reference Laboratory Network collects and analyses laboratory data on new cases of disease caused by the Mycobacterium tuberculosis complex. In 2011, a total of 1,057 cases were identified bacteriologically; an annual reporting rate of 4.6 cases per 100,000 population. Eighteen children aged less than 15 years plus an additional 11 children from the Torres Strait Protected Zone had bacteriologically-confirmed tuberculosis. Results of in vitro drug susceptibility testing were available for 1,056 isolates for isoniazid, rifampicin, ethambutol, and pyrazinamide. A total of 107 (10.0%) isolates of M. tuberculosis were resistant to at least one of these anti-tuberculosis agents. Resistance to at least isoniazid and rifampicin (defined as multi-drug resistance, MDR) was detected in 25 (2.4%) isolates; 18 were from the respiratory tract (sputum n=14, bronchoscopy n=3, tissue n=1). Ten (55.6%) of the MDR-TB-positive sputum specimens were smear-positive, as was a single sample from a lymph node. Ten patients with MDR-TB were Papua New Guinea (PNG) nationals in the Torres Strait Protected Zone. If these PNG nationals are excluded from the analysis, the underlying MDR-TB rate in Australia was 1.4%. No cases of extensively drug-resistant TB (defined as MDR-TB with additional resistance to a fluoroquinolone and an injectable agent) were detected in 2011.


Asunto(s)
Farmacorresistencia Bacteriana Múltiple , Mycobacterium tuberculosis/aislamiento & purificación , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Pulmonar/epidemiología , Adolescente , Adulto , Distribución por Edad , Anciano , Informes Anuales como Asunto , Antituberculosos/uso terapéutico , Australia/epidemiología , Niño , Preescolar , Notificación de Enfermedades/estadística & datos numéricos , Emigración e Inmigración , Monitoreo Epidemiológico , Femenino , Humanos , Incidencia , Laboratorios , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/crecimiento & desarrollo , Estudios Retrospectivos , Distribución por Sexo , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/etnología , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/etnología , Tuberculosis Pulmonar/microbiología , Población Blanca
9.
Acta Chim Slov ; 61(4): 866-74, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25551728

RESUMEN

Diaryldithiophosphate complexes of mono- and dibutyltin(IV) corresponding to [(ArO)(2)PS(2)(n)Sn(nBu)xCl(4-x-n)] (Ar = o-CH(3)C(6)H(4), m-CH(3)C(6)H(4), p-CH(3)C(6)H(4), 4-Cl-3-CH(3)C(6)H(3), (3,5-CH(3))(2)C(6)H(3); n = 1, 2 for x = 1 and n = 2 for x = 2) were successfully isolated and characterized by elemental analyses, IR, multinuclear NMR ((1)H, (13)C, (31)P and (119)Sn) spectroscopy and X-ray analysis. The thermal properties of the complex [(3,5-CH(3))(2)C(6)H(3)O(2)PS(2)](2)Sn(nBu)(2) (12) have been examined by combined DTA/ DTG thermal analyses. Single crystal X-ray analysis of [(3,5-CH(3))(2)C(6)H(3)O(2)PS(2)](2)S(n)(nBu)(2) (12) revealed that two diaryldithiophosphate ions are coordinated to tin atom in an anisobidentate fashion through the sulfur atoms of each dithiophosphate moiety leading to distorted skew-trapezoidal bipyramidal geometry. The antifungal activity depicts that these complexes are active against fungus Penicillium chrysogenium.


Asunto(s)
Antifúngicos/química , Organofosfatos/química , Compuestos Orgánicos de Estaño/química , Penicillium chrysogenum/efectos de los fármacos , Antifúngicos/síntesis química , Cristalografía por Rayos X , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Organofosfatos/síntesis química , Compuestos Orgánicos de Estaño/síntesis química
10.
Bioinorg Chem Appl ; 2013: 261731, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23983670

RESUMEN

New complexes of manganese(II) corresponding to [{(ArO)2PS2}2Mn] and [{(ArO)2PS2}2Mn.nL] (Ar = o-, m-, p-CH3C6H4 and p-Cl-m-CH3C6H3; n = 1, L = N2C12H8, N2C10H8; n = 2, L = NC5H5, P(C6H5)3) have been synthesized and characterized by microelemental analyses (C, H, and N), magnetic susceptibility, molar conductance, thermogravimetric, cyclic voltammetry, and spectral analyses including ESI mass spectrometry, IR, and UV-visible. The presence of a four-and-six coordinated Mn atoms has been established in the complexes and adducts, respectively. Antimicrobial screening of the complexes against gram negative bacteria E. coli, K. pneumonia, and P. aeruginosa and fungus S. rolfsii has shown potential bioactivity.

11.
Anaerobe ; 18(3): 366-8, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22710415

RESUMEN

Catabacter hongkongensis is a recently recognised anaerobic gram positive bacillus. We report the isolation of a C. hongkongensis strain that does not utilise mannose, a novel phenotype, from the blood cultures of a patient with a perforated appendix. The isolate was identified by 16s rRNA gene sequencing. This case highlights the difficulties with phenotypic identification of rare anaerobic isolates. It also illustrates the association of C. hongkongensis bacteraemia with a gastrointestinal source and intestinal perforation.


Asunto(s)
Apendicitis/diagnóstico por imagen , Bacteriemia/diagnóstico , Bacterias Grampositivas/aislamiento & purificación , Infecciones por Bacterias Grampositivas/diagnóstico , Apendicitis/complicaciones , Apendicitis/microbiología , Bacteriemia/microbiología , Medios de Cultivo , Bacterias Grampositivas/metabolismo , Infecciones por Bacterias Grampositivas/microbiología , Humanos , Masculino , Manosa/metabolismo , Persona de Mediana Edad , Fenotipo , Radiografía
12.
J Org Chem ; 77(12): 5286-96, 2012 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-22551444

RESUMEN

An efficient synthesis of (-)-kainic acid, through a high-pressure-promoted Diels-Alder cycloaddition of a vinylogous malonate derived from 4-hydroxyproline, is described. The bicyclic adduct could be converted into the natural product with complete stereocontrol.


Asunto(s)
Ácido Kaínico/síntesis química , Ciclización , Hidroxiprolina/química , Ácido Kaínico/química , Malonatos/química , Estructura Molecular , Estereoisomerismo
13.
J Am Chem Soc ; 134(2): 1344-51, 2012 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-22148234

RESUMEN

Various 2-thienyllithium derivatives were investigated in the solid state by X-ray diffraction and in solution by 2D NMR experiments. The determined structures of [(Et(2)O)Li(C(4)H(3)S)](4) (1), [(THF)(2)Li(C(4)H(3)S)](2) (2), [(DME)Li(C(4)H(3)S)](2) (3), [(TMEDA)Li(C(4)H(3)S)](2) (4), and [(PMDETA)Li(C(4)H(3)S)] (5) (DME = 1,2-dimethoxyethane, TMEDA = N,N,N',N'-tetramethylethylene-1,2-diamine, and PMDETA = N,N,N',N",N"-pentamethyldiethylenetriamine) were solved in nondonating toluene and provide firm ground for diffusion-ordered NMR spectroscopy as well as heteronuclear Overhauser enhancement NMR spectroscopy. The distance relation of nuclear Overhauser effects with a factor of r(-6) is employed to gain further insight into the aggregation degree of 1-5 in solution. Comparison of the slope provided by the linear region of the buildup curves and of the ∑r(-6) calculated distances from the crystal structures offers a handle to judge the structure retention versus conversion in solution. The structures of 3-5 are maintained in toluene solution. The data of 2, however, indicate a partial dissociation or a rapid exchange between the vertices of a tetrameric core and free THF molecules. Auxiliary exchange spectroscopy investigations showed that the signals of the nitrogen donor base containing compounds 4 and 5 exchange with the signals of nonlithiated thiophene. This is explained by exchange of the deuterium by a hydrogen atom via lithiation of toluene molecules.

14.
Dalton Trans ; 40(8): 1662-71, 2011 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-21203623

RESUMEN

Reactions of lithium dialkyl/phenyl phosphanylmethylides, RR'PCH(X)Li (R, R' = Me, Et, Ph and R = Me, R' = Ph; X = H or Me), with sulfur diimides S(NR'')2 (R'' = (t)Bu or SiMe3) in an equimolar ratio yielded Janus head complexes with the structural motif [Li{RR'PCH(X)S(NR'')2}]2 (R'' = (t)Bu, SiMe3). The basic core of these dimeric complexes is composed of a (LiN)(2) four-membered ring containing two four-coordinated lithium atoms. A lithium complex of the new Janus head ligand with another structural motif [TMEDA·Li{Ph(2)PCH(2)S(NSiMe3)2}] (6) could be isolated from the reaction of [Ph2PCH2Li·TMEDA] with S(NSiMe3)2. Two monomeric complexes [Mg{Me2PCH2S(NR'')2}2] (7, 8) were synthesised by a straightforward reaction of [Li{Me2PCH2S(NR'')2}2] with MgCl2 in pentane. The magnesium atom is chelated by one phosphorus atom and two nitrogen atoms of each unit of the hemilabile ligand in a tripodal manner, leading to octahedral geometry around the magnesium cation. A complete analysis of [Ph2PCH2(SNSiMe3)(HNSiMe3)] (9) is also described in which one nitrogen atom of the imido moiety is protonated.

15.
J Clin Microbiol ; 47(1): 268-70, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19020056

RESUMEN

Mycobacterium heckeshornense is a slow-growing nontuberculous mycobacterium first characterized in 2000. It is reported to cause lung disease and tenosynovitis. We report a case of isolated massive axillary lymphadenopathy in an elderly woman, where histology showed necrotizing granulomata and M. heckeshornense was isolated as the causative organism.


Asunto(s)
Linfadenitis/microbiología , Infecciones por Mycobacterium/diagnóstico , Mycobacterium/aislamiento & purificación , Anciano de 80 o más Años , Axila/patología , Femenino , Granuloma/microbiología , Granuloma/patología , Humanos , Mycobacterium/clasificación , Infecciones por Mycobacterium/microbiología , Necrosis/microbiología , Necrosis/patología
16.
J Org Chem ; 72(20): 7769-70, 2007 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-17824714

RESUMEN

The transformation of aldehydes into terminal olefins through reduction of the corresponding enol triflates is described. The method is effective with both linear and alpha-branched aldehydes.

17.
Chemistry ; 13(13): 3636-42, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17266157

RESUMEN

Starting from tris(benzothiazol-2-yl)phosphane (1) an advanced Janus-head ligand, di(benzothiazol-2-yl)phosphane (2), was synthesised and structurally characterised. The heteroaryl substituents of this ligand provide both hard and soft donor sites. Surprisingly, the phosphorus atom in 2 is divalent and the hydrogen atom is directly bonded to one ring nitrogen atom and hydrogen bonded to the second. Compound 2 decomposes in any common solvent other than diethyl ether and a new preparation to improve the yields of 2 is presented. A coordination polymer, [{Cs(bth)(2)P}8] (3) (bth=benzothiazol-2-yl), was obtained when the sec-phosphane 2 was allowed to react with elemental caesium in a 1:1 ratio in diethyl ether at -78 degrees C. In 3 each anion is coordinated to four caesium cations and vice versa. The central phosphorus atom is coordinated to two metal atoms above and below the mean plane of the anion in positions in which the two lone pairs of a four-electron donor are anticipated. Two additional cations micro-bridge both ring nitrogen atoms. Hence both faces of the Janus-head ligand are coordinated to the same number of metal cations but in a different way.

18.
Org Lett ; 8(24): 5665-8, 2006 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-17107098

RESUMEN

The first Diels-Alder based synthesis of (-)-kainic acid is described. Danishefsky's diene and a vinylogous malonate derived from 4-hydroxyproline combine under high pressure to afford a key bicyclic intermediate with virtually no loss of enantiopurity. This adduct can be converted into the natural product with complete stereocontrol. [reaction: see text].


Asunto(s)
Ácido Kaínico/síntesis química , Compuestos Bicíclicos con Puentes/síntesis química , Hidroxiprolina/química , Indicadores y Reactivos , Toxinas Marinas/química , Conformación Molecular , Presión , Estereoisomerismo
19.
J Vet Diagn Invest ; 18(6): 619-22, 2006 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-17121097

RESUMEN

A 7-year-old dairy cow presented with clinical signs of neurologic disease. Despite treatment with penicillin, the cow died 36 hours after initial presentation. Necropsy examination revealed multiple foci of hemorrhage within the cerebrum and thickened meninges. Additionally, endometritis and consolidation of approximately 30% of both lungs was observed. Histology revealed necrotizing vasculitis, infarction, and hemorrhage within sections of the brain, uterus, and lung. Large numbers of intralesional fungal hyphae were visible. Because only formalin-fixed tissue was available, polymerase chain reaction was used to make an etiologic diagnosis of Mortierella wolfii.


Asunto(s)
Enfermedades de los Bovinos/microbiología , Meningoencefalitis/veterinaria , Mortierella/aislamiento & purificación , Mucormicosis/veterinaria , Animales , Autopsia/veterinaria , Bovinos , Enfermedades de los Bovinos/patología , Cerebro/microbiología , Cerebro/patología , Resultado Fatal , Femenino , Meningoencefalitis/microbiología , Meningoencefalitis/patología , Mortierella/genética , Mucormicosis/diagnóstico , Mucormicosis/patología , Reacción en Cadena de la Polimerasa
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