RESUMEN
BACKGROUND: Conclusive evidence supports the importance of fundamental movement skills (FMS) proficiency in promoting physical activity and countering obesity. In children with Down Syndrome (DS), FMS development is delayed, which has been suggested to be associated with balance deficits. This study therefore examined the relationship between FMS proficiency and balance ability in children with DS, with the aim of contributing evidence to programmes that address FMS delay. METHODS: Participants consisted of 20 children with DS (7.1 ± 2.9 years old) and an age-matched control group of children with typical development (7.25 ± 2.5 years). In the first part of the study, FMS (i.e. locomotor and object control) proficiency of the children was tested using the Test of Gross Motor Development-2. Balance ability was assessed using a force platform to measure centre of pressure average velocity (AV; mm/sec), path length (mm), medio-lateral standard deviation (mm) and antero-posterior standard deviation (mm). In the second part of the study, children with DS participated in 5 weeks of FMS training. FMS proficiency and balance ability were tested post-training and compared to pre-training scores. Verbal and visuo-spatial short-term memory capacities were measured at pre-training to verify the role of working memory in skill learning. RESULTS: FMS proficiency was associated with centre of pressure parameters in children with DS but not in children with typical development. After controlling for age, AV was found to predict significant variance in locomotor (R2 = 0.61, P < 0.001) and object control (R2 = 0.69, P < 0.001) scores. FMS proficiency and mastery improved after FMS training, as did AV, path length and antero-posterior standard deviation (all P < 0.05). Verbal and visuo-spatial short-term memory did not interact with the effects of training. CONCLUSIONS: Children with DS who have better balance ability tend to have more proficient FMS. Skill-specific training improved not only FMS sub-skills but static balance stability as well. Working memory did not play a role in the changes caused by skills training. Future research should examine the causal relationship between balance and FMS.
Asunto(s)
Desarrollo Infantil/fisiología , Síndrome de Down/fisiopatología , Locomoción/fisiología , Destreza Motora/fisiología , Equilibrio Postural/fisiología , Niño , Femenino , Humanos , Masculino , Memoria a Corto Plazo/fisiologíaRESUMEN
The C5O5(2-) and relatively unstable C6O6(2-) dianions, each serving as a hub for binding with a set of convergent NH donor groups of four phenylurea molecules, have been generated in situ and stabilized in nearly isostructural hydrogen-bonded host lattices.
RESUMEN
A novel luminescent acetylenediide-bridged tetranuclear copper(I) complex [Cu4(mu-Ph2Ppypz)4(mu 4-eta 1,eta 2-C identical to C)]-(ClO4)2 [Ph2Ppypz = 2-(diphenylphosphino-6-pyrazol-1-yl)pyridine] has been synthesized and structurally characterized by X-ray crystallography.
RESUMEN
Two furanoditerpenoid lactones, were isolated from the seeds of Caesalpinia minax Hance. Their structures and stereochemistry have been established by spectral data and single crystal X-ray analysis.
Asunto(s)
Diterpenos/química , Diterpenos/aislamiento & purificación , Medicamentos Herbarios Chinos/aislamiento & purificación , Lactonas/química , Lactonas/aislamiento & purificación , Plantas Medicinales/química , Cristalografía por Rayos X , Medicamentos Herbarios Chinos/química , Semillas/químicaRESUMEN
A new labdane diterpene, heteronone B (1), together with a known labdane diterpene, heteronone A (2), have been isolated from the aerial part of Leonurus heterophyllus. Their structures were established mainly by 1D and 2D NMR analysis and the stereochemistry of 2 was confirmed by single-crystal X-ray diffraction analysis.
Asunto(s)
Diterpenos/química , Leonurus/química , Componentes Aéreos de las Plantas/química , Plantas Medicinales/química , China , Cromatografía , Diterpenos/aislamiento & purificación , Estructura Molecular , Espectrofotometría , Difracción de Rayos XRESUMEN
A series of novel double salts of silver(I) were isolated by dissolving Ag(2)C(2) in a concentrated aqueous solution of R(F)CO(2)Ag (R(F) = CF(3), C(2)F(5)) and AgBF(4). Different ancillary solvento ligands such as H(2)O, CH(3)CN, and C(2)H(5)CN were found to affect the crystallization process that led to the assembly of various silver(I) cages with embedded C(2)(2-) ions. 2Ag(2)C(2) x 12CF(3)CO(2)Ag x 5H(2)O (1) consists of two independent C(2)@Ag(7) cages, each having the shape of a basket with a square base. Ag(2)C(2) x 6CF(3)CO(2)Ag x 3CH(3)CN (2) contains a zigzag chain of edge-sharing triangulated dodecahedra, and 4Ag(2)C(2) x 23CF(3)CO(2)Ag x 7C(2)H(5)CN x 2.5H(2)O (3) features an unusual double-walled silver column constructed from the fusion of four different kinds of irregular polyhedra. Ag(2)C(2) x 10C(2)F(5)CO(2)Ag x 9.5H(2)O (4), Ag(2)C(2) x 9C(2)F(5)CO(2)Ag x 3CH(3)CN x H(2)O (5), and Ag(2)C(2) x 6C(2)F(5)CO(2)Ag x 2C(2)H(5)CN (6) all contain an edge-sharing double cage with each single cage in the shape of a square antiprism, a capped square antiprism, and a triangulated dodecahedron, respectively.
RESUMEN
The bridging phosphine ligand 2,6-bis(diphenylphosphino)pyridine (L) was used to synthesize a new, neutral organometallic ligand [Fe(CO)(4)](2)(micro-L) 1, which exhibits eclipsed and staggered conformations in two crystalline forms. This Fe,N,Fe-tridentate ligand reacts with silver perchlorate to form the hetero-trinuclear complex [[Fe(CO)(4)](2)Ag(micro-L)](ClO(4)) 2, in which the central silver(I) atom bridges a pair of iron(0) atoms at Fe-Ag distances of 2.627(3) and 2.652(3) A; the Fe-Ag-Fe angle is 170.98(9) degrees. The reaction of 1 with mercury(II) chloride gives [Fe(CO)(4)](2)Hg(2)Cl(4)(micro-L), 3. The ligand also reacts with mercury(II) acetate to form a hetero-octanuclear complex [[Fe(CO)(3)Hg](2)(micro-L)](2) 4 and a novel hetero-heptanuclear complex Fe(3)(CO)(8)Hg(4)(micro-L)(2)(MeCO(2))(2) 5. Complex 4 displays a square metallic core in which the iron and mercury atoms occupy the corners and the centers of the edges, respectively. The metal atoms in 5 are linked to form a kinky line with bends at the iron atoms.
RESUMEN
From ABRUS PRECATORIUS Abl. triterpenoids abruslactone, methyl abrusgenate and abrusgenic acid were isolated and elucidated by spectroscopic and X-ray techniques.
RESUMEN
C8H9N3OS, monoclinic, C2/c, a = 14.206 (3), b = 14.244 (4), c = 10.457 (4) A, beta = 116.18(2) degrees, V = 1898.9 (8) A3, Z = 8, Dm = 1.387, D chi = 1.366 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 2.90 cm-1, F(000) = 816.0, T = 298 K, final R = 0.0429 for 1322 observed reflections. The S and hydrazinic N atoms lie trans. The lowering of antibacterial activity compared to that of 4-phenylthiosemicarbazide may be correlated with the decrease in negative charge on the hydrazinic N atom. The crystal structure is stabilized by hydrogen bonding, stacking interactions and van der Waals forces.
Asunto(s)
Aldehídos , Antiinfecciosos , Tiosemicarbazonas , Modelos Moleculares , Conformación Molecular , Programas Informáticos , Difracción de Rayos X/métodosRESUMEN
Tetrakis(4-nitrophenyl)methane is a new host material with considerable structural adaptability over a range of solvents. The crystal structures of 14 of these solvates have been determined and classified into three groups. The diamondoid group, wherein the host molecules form a 2-fold interpenetrated diamondoid network structure, is unprecedented in that network connections are made exclusively with weak C-H...O and pi...pi interactions. This group consists of the solvates of THF, dioxane, nitrobenzene, 4-bromoanisole, anisole, phenetole, p-xylene, and chlorobenzene. The rhombohedral group, which is characterized by specific host.guest interactions of the C-H...O and halogen...O2N type, consists of the solvates of CHCl3 and CHBr3 and somewhat surprisingly DMF, which shows an unusual 3-fold disorder mimicking in part the shape and size of the haloform molecules though not their orientation. The third group comprises solvent-rich solvates of the host with mesitylene, collidine, and o-xylene with quite different crystal structures. The THF solvate was found to lose solvent over limited temperature ranges transforming reversibly from the diamondoid structure to the rhombohedral structure. A mechanism for this process is outlined. Material from which solvent has been removed by heating was also found to resolvate upon soaking in appropriate solvents. In summary, the title compound forms a host network that is partially robust and in part flexible. It is possible that this fluxional nature of the host network derives from the weakness of the connecting interactions.
RESUMEN
A bioassay-guided study led to the isolation of five new cassane furanoditerpenes, designated as caesalmin C (1), D (2), E (3), F (4), and G (5), along with stigmasterol (6) from the seeds of Caesalpinia minax. The (1)H and (13)C NMR spectra were completely assigned by using a combination of 2D NMR analyses. The structures of all five furanoditerpenes were confirmed by X-ray analyses. The structure of 6 was verified by X-ray analysis for the first time. The bioassay results showed that the anti-Para3 virus activity of tetracyclic furanoditerpenoids 1-4 is more potent than that of the furanoditerpenoid lactone 5, which is in turn better than 6. As the major components of the plant possess significant potent activity, it may be feasible to develop new antiviral agents from this source.
Asunto(s)
Antivirales/aislamiento & purificación , Diterpenos/aislamiento & purificación , Medicamentos Herbarios Chinos/aislamiento & purificación , Fabaceae/química , Furanos/aislamiento & purificación , Plantas Medicinales/química , Antivirales/química , Antivirales/farmacología , Células Cultivadas/efectos de los fármacos , Cromatografía en Capa Delgada , Cristalografía por Rayos X , Efecto Citopatogénico Viral , Diterpenos/química , Diterpenos/farmacología , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Medicamentos Herbarios Chinos/química , Medicamentos Herbarios Chinos/farmacología , Furanos/química , Furanos/farmacología , Concentración 50 Inhibidora , Espectroscopía de Resonancia Magnética , Conformación Molecular , Estructura Molecular , Virus de la Parainfluenza 3 Humana/efectos de los fármacos , Ribavirina/farmacología , Semillas/química , Espectrofotometría Infrarroja , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier , EstereoisomerismoRESUMEN
A combined use of alpha-lithiation and nucleophilic substitutions of N,N-dimethyl 3,4-bis(trimethylsilyl)-1H-pyrrole-1-sulfonamide 8c led to several 2-substituted 3, 4-bis(trimethylsilyl)-1H-pyrrole-1-sulfonamides. Utilizing the beta-effect of a trimethylsilyl group, a highly regioselective synthesis of 2,3,4-trisubstituted 1H-pyrroles 23 and 34 was accomplished. The marine natural product lukianol A (3) was prepared utilizing this strategy.
Asunto(s)
Antineoplásicos/síntesis química , Pirazoles/síntesis química , Pirroles , Antineoplásicos/química , Indicadores y Reactivos , Espectroscopía de Resonancia Magnética , Conformación Molecular , Estructura Molecular , Pirazoles/químicaRESUMEN
Mixed halocarborane anions, 1-H-CB11Y5X6- (X, Y = Cl, Br, I), have been prepared by treatment of [Me3NH][1-H-CB11H5X6] (X = Cl, Br, I) with proper halogenating reagents at 180-220 degrees C in a sealed tube in high yield. These new anions are fully characterized by 1H, 13C, and 11B NMR, IR, and negative-ion MALDI MS spectroscopy. Some are further confirmed by single-crystal X-ray analyses. The weakly coordinating nature of these anions is probed by 29Si chemical shifts of the resulting Pri3Si(1-H-CB11Y5X6) compounds. The results suggest that the coordinating ability of these anions is mainly dependent on the substituents at 7-12 positions (namely, X atoms), and the contribution from the upper belt substituents Y is relatively small. These suggestions are consistent with the results obtained from the structural study of silver salts of mixed halo- and perhalocarborane anions.
RESUMEN
The highly chlorinated, brominated, and iodinated carborane anions 1-R-CB9X9- (R = H, NH2; X = Cl, Br, I) were prepared in high yields by treatment of [Me3NH][1-R-CB9H9] with excess ICl, Br2/triflic acid, and I2/triflic acid, respectively, in sealed tubes at 180-240 degrees C. With the aid of a Pd catalyst, B-I bonds could be converted into the B-Me bonds by treatment with excess MeMgBr, which led to the preparation of the permethylated species 1-H-CB9Me9- in good yield. These new anions were fully characterized by 1H, 13C, and 11B NMR, IR, and negative-ion MALDI MS spectroscopy. Some were further characterized by single-crystal X-ray analyses. The weakly coordinating nature of these new anions was probed by 29Si chemical shifts.
RESUMEN
The C3-symmetric tripodal ligand tris(2-benzimidazolylmethyl)amine (ntb) and its alkyl-substituted derivatives tris(N-R-benzimidazol-2-ylmethyl)amine (R = methyl, Mentb; R = ethyl, Etntb; R = propyl, Prntb) react with various silver(I) salts to afford mononuclear [Ag(Prntb)(CF3SO3)].0.25H2O, 1, binuclear [Ag2(Mentb)2](CF3SO3)2.H2O, 2, trinuclear [Ag3(Etntb)2](ClO4)3.CH3OH, 3, and tetranuclear [Ag4(ntb)2(CH3CN)2(CF3CO2)2](CF3CO2)2.2H2O, 4. All four complexes have been characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. The Ag(I) ion in 1 is coordinated to the three imine nitrogen atoms of the Prntb ligand and one oxygen atom of the trifluoromethanesulfonate anion in a distorted tetrahedral environment. Dinuclear 2 has C2 symmetry with each Ag(I) atom trigonally coordinated by two arms of one Mentb and one arm of another. Trinuclear 3 has C3 symmetry with a Ag3 regular triangle sandwiched between a pair of Etntb ligands such that one arm of each ligand is involved in linear coordination about an Ag(I) atom. In the tetranuclear complex 4, two linearly coordinated Ag(I) atoms lying on the molecular C2 axis are bridged by a pair of ntb ligands and the remaining pendant arm of each ntb ligand is attached to another Ag(I) atom whose tetrahedral coordination sphere is completed by an acetonitrile molecule and a chelating trifluoroacetate anion. Complexes 2 and 3 may be regarded as an aggregation of two tridentate ligands by a silver dimer and a trinuclear cluster with weak Ag...Ag interactions, respectively, while in 4 the aggregation of two tripodal ligands by four Ag(I) ions affords a multicomponent internal cavity. The packing modes of complexes 1-3 are dominated by weak supramolecular pi...pi and CH...pi interactions. Hexagonal or square channels are generated in 1 and 2, and a honeycomb layer structure is formed in 3 with solvate molecules and counteranions occupying the voids. The crystal structure of 4 consists of a three-dimensional network consolidated by NH...O and OH...O hydrogen bonds.
RESUMEN
Mikanin-3-O-sulfate (1), in the form of its potassium salt, together with mikanin (2) and alpinetin (3) were isolated from Mikania micrantha. The crystal structures of K(1) x CH3OH, 2 and 3 x H2O were established by X-ray crystallography. The potassium ions in K(1) x CHO3H are bridged by O5, O7 and O8 to form a chain of face-sharing KO8 coordination polyhedra, from which the aglycon units are outstretched to form a polymeric molecular column. Adjacent molecular columns are linked by pi-pi stacking between parallel, intercalating aglycon units to form layers matching the (101) family of planes, which are further interconnected into a three-dimensional supramolecular assembly. Sulfation at 3-OH induced better co-planarity and conjugation of the rings.
Asunto(s)
Flavonoides/química , Metanol/química , Asteraceae/química , Cristalografía por Rayos X , Modelos Moleculares , Conformación Molecular , Hojas de la Planta/químicaRESUMEN
The binuclear cobalt(II) amide complex [(CoL2)2-(TMEDA)] (1) [L = N(Si(t)BuMe2)(2-C5H3N-6-Me); TMEDA = Me2NCH2CH2NMe2] has been synthesized by the reaction of anhydrous CoCl2 with 2 equiv of [Li(L)(TMEDA)]. X-ray crystallography revealed that complex 1 consists of two [CoL2] units linked by one TMEDA ligand molecule, which binds in an unusual N,N'-bridging mode. Protolysis of 1 with the bulky phenol Ar(Me)OH (Ar(Me) = 2,6-(t)Bu2-4-MeC6H2) and thiophenol ArSH (Ar = 2,4,6-(t)Bu3C6H2) gives the neutral monomeric cobalt(II) bis(aryloxide) [Co(OAr(Me))2(TMEDA)] (2) and dithiolate [Co(SAr)2(TMEDA)] (3), respectively. Complexes 1-3 have been characterized by mass spectrometry, microanalysis, magnetic moment, and melting-point measurements, in addition to X-ray crystallography.
Asunto(s)
Aminopiridinas/química , Compuestos Organometálicos/química , Compuestos Organometálicos/síntesis química , Fenómenos Químicos , Química Física , Cristalografía por Rayos X , Indicadores y Reactivos , Modelos Moleculares , Estructura MolecularRESUMEN
A series of 14 heteroleptic rare earth sandwich complexes [M(III)-(nc)(oep)] (M=Y, La-Lu except Ce and Pm; nc=2,3-naphthalocyaninate; oep = octaethylporphyrinate) have been prepared by a one-pot procedure from corresponding [M(acac)3] . nH2O (acac = acetylacetonate), metal-free porphyrin H2(oep), and naphthalonitrile the presence of 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) in n-octanol. The molecular structures of four of these complexes (M = Sm, Gd, Y, Lu) are isostructural, exhibiting a slightly distorted square antiprismatic geometry with two domed ligands. The interplanar distance decreases from 2.823 to 2.646 A along the series as a result of lanthanide contraction. The whole series of complexes have also been characterized spectroscopically. All the electronic absorptions, except the two B-bands due to nc and the oep rings, are metal-dependent, indicating that there are substantial pi-pi interactions. The hole or the unpaired electron in these double-deckers is delocalized over both macrocyclic ligands, as evidenced by the co-appearance of the IR marker bands for the nc*- (1315-1325 cm(-1)) and oep*- (1510-1531 cm(-1)) T radical ions. Three one-electron oxidation couples and up to three one-electron reduction couples have been revealed by electrochemical methods. All the potentials are linearly dependent on the size of the metal center. The changes in absorption spectra during the first electro-oxidation and reduction of the La(III), Eu(III), and Y(III) double-deckers have also been studied spectroelectrochemically. The spectral data recorded for [M(III)(nc)(oep)]-(M = Y, La-Lu except Ce and Pm) reduced chemically with hydrazine hydrate are in accord with those obtained by spectroelectrochemical methods. The first heteroleptic naphthalocyaninate-containing triple-deckers [M(III)2(nc)-(oep)2] (M = Nd, Eu) have also been prepared by a raise-by-one-story method by using [M(III)(nc)(oep)] (M = Nd, Eu), [M(acac)3] . nH2O (M = Nd, Eu), and H2(oep) as starting materials. The compounds adopt a symmetrical triple-decker structure with two outer oep rings and one inner nc ring, which has been confirmed by 'H NMR spectroscopy and X-ray structural determination of the Nd complex. Both compounds give a near-IR absorption at 1021 nm (for M=Nd) or 1101 nm (for M = Eu), which has rarely been observed for neutral (or hole-free) triple-decker complexes and can be ascribed to the lowest-energy Q'(0, 0) transition. Similarly to the double-decker analogues. these triple-decker complexes undergo a series of one-electron transfer processes with a relatively small potential gap (1.1 -1.2 V) between the first oxidation and the first reduction.