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Strong N (strong + n)

Distribution by Scientific Domains
Chemistry87%

Selected Abstracts

Naphthalene-1,5-diammonium bis[trifluoridostannate(II)]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2007
Sihem Boufas
The structure of the title compound, (C10H12N2)[SnF3]2, is made up of alternating layers of cations and anions, where the anion layers form extended polymeric sheets through a series of secondary Sn...F bonds. Strong N,H...F hydrogen bonds crosslink adjacent cation and anion layers, thereby building a three-dimensional network. [source]

Theoretical Studies on Metal,Metal Interaction and Intrinsic 1,3[,*(d),(s/p)] Excited States of Dinuclear d10 Complexes with Bridging Phosphane Ligands

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2006
Qing-Jiang Pan
Abstract To explore the metal,metal interaction and spectroscopic properties, the ground- and excited-state structures of [M2(dpm)2]2+ [M = Ag (2), Cu (3), dpm = bis(diphosphanyl)methane] and their solvated species [M2(dpm)2]2+·(MeCN)2 were optimized by the MP2 and CIS methods, respectively. In the ground states, the calculated M,M distances and their corresponding M,M stretching frequencies for 2 and 3 indicate the presence of metallophilic attraction; there is strong N,Cu/Ag coordination in acetonitrile, which is different from the case in previous studies of [Au2(dpm)2]2+ (1). CIS calculations show that 2 and 3 have 1,3[,*(d),(s/p)] as their lowest-energy excited state, as is also the case for 1, confirmed by unrestricted MP2 calculations. On the basis of the CIS-optimized structures, the TD-DFT (B3LYP) method was employed to calculate the emission spectra of such complexes. For 3, the phosphorescent emissions were calculated at 424 and 514 nm in the solid state and acetonitrile, which is comparable to the experimental data of 475 and 480 nm, respectively. The comparison between the gas-phase and solution emissions for 1,3 reveals that the N,M coordination results in a large red-shift of the emission wavelength. Taking previous studies into account , we found that the M,M distances are linearly correlated with the M,M stretching frequencies for the dinuclear d10 complexes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Poly[bis(,-benzene-1,4-dicarboxylato)bis[,-6-(4-pyridyl)-5H -imidazolo[4,5- f][1,10]phenanthroline]dilead(II)]: an interpenetrating ,-Po net

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2010
Zhan-Lin Xu
The asymmetric unit of the title compound, [Pb2(C8H4O4)2(C18H11N5)2]n, contains two PbII atoms, two benzene-1,4-dicarboxylate (1,4-bdc) dianions and two 6-(4-pyridyl)-5H -imidazolo[4,5- f][1,10]phenanthroline (L) ligands. Each PbII atom is eight-coordinated by three N atoms from two different L ligands and five carboxylate O atoms from three different 1,4-bdc dianions. The two 1,4-bdc dianions (1,4-bdc1 and 1,4-bdc2) show different coordination modes. Each 1,4-bdc1 coordinates to two PbII atoms in a chelating bis-bidentate mode. Each carboxylate group of the 1,4-bdc2 anion connects two PbII atoms in a chelating,bridging tridentate mode to form a dinuclear unit. Neighbouring dinuclear units are connected together by the aromatic backbone of the 1,4-bdc dianions and the L ligands into a three-dimensional six-connected ,-polonium framework. The most striking feature is that two identical three-dimensional single ,-polonium nets are interlocked with each other, thus leading directly to the formation of a twofold interpenetrated three-dimensional ,-polonium architecture. The framework is held together in part by strong N,H...O hydrogen bonds between the imidazole NH groups of the L ligands and the carboxylate O atoms of 1,4-bdc dianions within different ,-polonium nets. [source]

Dihydrogen phosphate mediated supramolecular frameworks in 2- and 4-chloroanilinium dihydrogen phosphate salts

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010
P. Balamurugan
The title compounds, 2-chloroanilinium dihydrogen phosphate (2CADHP) and 4-chloroanilinium dihydrogen phosphate (4CADHP), both C6H7NCl+·H2PO4,, form two-dimensional supramolecular organic,inorganic hybrid frameworks. In 2CADHP, the dihydrogen phosphate anions form a double-stranded anionic chain generated parallel to the [010] direction through O,H...O hydrogen bonds, whereas in 4CADHP they form a two-dimensional supramolecular net extending parallel to the crystallographic (001) plane into which the cations are linked through strong N,H...O hydrogen bonds. [source]

Hydrogen-bonded frameworks of bis(2-carboxypyridinium) hexafluorosilicate and bis(2-carboxyquinolinium) hexafluorosilicate dihydrate

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2007
Vladimir O. Gelmboldt
In bis(2-carboxypyridinium) hexafluorosilicate, 2C6H6NO2+·SiF62,, (I), and bis(2-carboxyquinolinium) hexafluorosilicate dihydrate, 2C10H8NO2+·SiF62,·2H2O, (II), the Si atoms of the anions reside on crystallographic centres of inversion. Primary inter-ion interactions in (I) occur via strong N,H...F and O,H...F hydrogen bonds, generating corrugated layers incorporating [SiF6]2, anions as four-connected net nodes and organic cations as simple links in between. In (II), a set of strong N,H...F, O,H...O and O,H...F hydrogen bonds, involving water molecules, gives a three-dimensional heterocoordinated rutile-like framework that integrates [SiF6]2, anions as six-connected and water molecules as three-connected nodes. The carboxyl groups of the cation are hydrogen bonded to the water molecule [O...O = 2.5533,(13),Å], while the N,H group supports direct bonding to the anion [N...F = 2.7061,(12),Å]. [source]

(S)- trans -Cyclohexane-1,2-dicarboximide

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2002
Maria Gdaniec
The molecule of the title compound, C8H11NO2, contains a strained bicyclic system with a significantly twisted imide chromophore. The five-membered ring fragment containing the imide function is strongly puckered and adopts a half-chair conformation. The six-membered ring has a slightly distorted chair conformation. The mol­ecules are joined by strong N,H,O and weak C,H,O hydrogen bonds into infinite chains. [source]

[(2E)-2-Benzyl­idene­hydrazino]­tri­cyclo­hexyl­phospho­nium chloride

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2001
Andrei S. Batsanov
In the title compound, C25H40N2P+·Cl,, the cation structure (at 150,K) is intermediate between those of the imino­phospho­rane and the yl­ide, consistent with delocalization of the positive charge between the P and the adjacent N atoms. The cation and anion are linked by a strong N,H,Cl hydrogen bond. [source]

Nutrient Limitation to Primary Productivity in a Secondary Savanna in Venezuela1

BIOTROPICA, Issue 4 2002
Nichole N. Barger
ABSTRACT We examined nutrient limitation to primary productivity in a secondary savanna in the interior branch of the Coastal Range of Venezuela, which was converted from forest to savanna more than 100 years ago. We manipulated soil nutrients by adding nitrogen (+N), phosphorus and potassium (+PK), and nitrogen, phosphorus, and potassium (+NPK) to intact savanna. Eleven months after fertilization, we measured aboveground biomass and belowground biomass as live fine roots in the top 20 cm of soil, and species and functional group composition in response to nutrient additions. Aboveground biomass was highest in the NPK treatment ([mean g/m2]; control = 402, +N = 718, +PK = 490, +NPK = 949). Aboveground production, however, appeared to be limited primarily by N. Aboveground biomass increased 78 percent when N was added alone but did not significantly respond to PK additions when compared to controls. In contrast to aboveground biomass, belowground biomass increased with PK additions but showed no significant increase with N (depth 0,20 cm; [mean g/m2]; control = 685, +N = 443, +PK = 827, +NPK = 832). There was also a 36 percent increase in root length with PK additions when compared to controls. Whole savanna shoot:root ratios were similar for control and +PK (0.6), while those for +N or +NPK fertilization were significantly higher (1.7 and 1.2, respectively). Total biomass response (above + belowground) to nutrient additions showed a strong N and PK co-limitation ([mean g/m2]; control = 1073, +N = 1111, +PK = 1258, +NPK = 1713). Aboveground biomass of all monocots increased with N additions, whereas dicots showed no response to nutrient additions. Trachypogon spp. (T. plumosus+T. vestitus) and Axonopus canescens, the two dominant grasses, made up more than 89 percent of the total aboveground biomass in these sites. Trachypogon spp. responded to NPK, whereas A. canescens, sedges, and the remaining monocots only responded to N. Even though nutrient additions resulted in higher aboveground biomass in N and NPK fertilized plots, this had little effect on plant community composition. With the exception of sedges, which responded positively to N additions and increased from 4 to 8 percent of die plant community, no changes were observed in plant community composition after 11 months. RESUMEN En este estudio se examinaron las limitaciones nutricionales en la productividad primatia de una sabana secundaria de más de 100 años localizada en el brazo interior de la Cordillera de la Costa de Venezuela. Se manipularon los nutrientes del suelo mediante la adición de nitrógeno (+N), fósforo y potasio (+PK), y nitrógeno, fósforo, y potasio (+NPK) al suelo de la sabana. Después de once meses de iniciarse los experimentos se midió la respuesta a la adición de nutrientes en términos de producción de biomasa aérea, biomasa de raíces finas vivas en los primeros 20 cm de suelo, y cambios en la composición de especies y grupos funcionales. La biomasa aérea fue mayor en las parcelas fertilizadas con N o en combinación de NPK ([promedio g/m2]; control = 402, +N = 718, +PK = 490, +NPK = 949) indicando que la producción aéiea está limitada principalmente por N. No hubo respuesta estadísticamente significativa a la adición de PK con respecto a los controles. La biomasa de raíces finas aumentó con la adición de PK y NPK mientras que no hubo aumento significativo con N (Profundidad 0,20 cm; [promedio g/m2]; control=685, +N=443, +PK=827, +NPK=832). La adición de PK modificó la arquitectura radical con un anmento de 36 por ciento en la longitud de las raíces con respecto al control. La relación vástago/raíz fue similar en los tratmientos controly + PK (0.6), pero significativamente mayor en +N (1.7)y +NPK(1.2) indicando nuevamente una limitación principal por N. La respuesta de la biomasa total (vástago +raíces vivas) a la adición de nutrientes refleja una colimitación de N y PK ([promedio g/m2]; control=1073, +N=1111, +PK+1258,+NPK=1713). La biomasa aérea de las monocotiledóneas aumentó de N, mientras que no hubo respuesta significativa a la adición de nutrientes en las dicotiledóneas. Trachypogon spp (T. Plumosus+T. vestitus) and Axonopus canescens, las dos gramíneas dominantes, representaron más del 89 por ciento de la biomasa total en las parcelas. Trachypogon spp respondieron a NPK, mientras que A. canescens, cuoeráceas, y las otras monocotiledóneas sólo respondieron a N. No hubo cambios significativos en la composición de especies como respuesta a la adición de nutrientes, con la excepción de las ciperáceas que respondieron significativamente a la adición de N con un aumento de 4 a 8 por ciento. [source]