Yellow Needles Research Articles

CRYSTAL CHEMISTRY OF URANYL MOLYBDATES. IV. THE STRUCTURES OF M2[(UO2)6(MoO4)7(H2O)2] (M = Cs, NH4)

Two new uranyl molybdate hydrates, M2[(UO2)6(MoO4)7(H2O)2] (M = Cs, NH4), have been synthesized using hydrothermal methods. The crystals occur as transparent yellow needles and yellow elongate plates for M = Cs and NH4, respectively. Their structures were solved by direct methods and refined on the basis of F 2 for all unique data collected with Mo K X-radiation and a CCD (charge-coupled device) detector. Final R1 values are 4.1 and 3.9% for M = Cs and M = NH4, respectively, calculated for 2178 and 2969 unique observed (|Fo| ≤ 4F) reflections, respectively. The compound Cs 2[(UO2)6(MoO4)7(H2O)2] is orthorhombic, space group Pbcm, a 13.990(2), b 10.808(1), c 25.671(3) A, V 3881.6(9) A 3 , Z = 4. The compound (NH4)2[(UO2)6(MoO4)7(H2O)2] is isostructural with the Cs analogue, a 13.970(1), b 10.747(1), c 25.607(2) A, V 3844.4(6) A 3 , Z = 4. The four symmetrically independent U 6+ cations in M2[(UO2)6(MoO4)7(H2O)2] are part of approximately linear (UO 2) 2+ uranyl ions (Ur) that are further coordinated by five ligands at the equatorial positions of uranyl pentagonal bipyramids that are capped by O Ur atoms. The four symmetrically identical Mo 6+ cations are tetrahedrally coordinated by O atoms. The uranyl and molybdate polyhedra link by vertex sharing to form a framework, with the low-valence M cations located in voids within the framework.

Free radical 4‐nitrophenylation of thieno[2,3‐b]pyridine. Part 2: Isolation and structural studies of three samples of mono (4‐nitrophenyl) products; relative yields of the five possible isomers

AbstractFrom the crude mixtures of isomeric 4‐nitrophenylthieno[2,3‐b]pyridines (3) previously reported [1] were isolated three analytically pure samples, viz. the 2‐isomer (yellow needles, mp 258°, 3a), the 6‐isomer (red prisms, mp 182°, 3e), and a ternary mixture of the 2‐, 3‐, and 4‐isomers (orange needles, mp 213°, 3a:3b:3c = 1.3:1.0:0.5). The 258° compound was identified as either 3a or 3b by its 1H nmr spectrum and definitively as the former by its x‐ray crystallographic analysis. The isomeric identities of the 182° and 213° samples were established from their 1H nmr spectra only. No 5‐isomer (3d) was identified. Semi‐quantitatively, relative isomeric yields fit the pattern 2‐ (64%)>>6‐ (14%)≥3‐ (12%)>4‐ (6%)≥5‐(≤4%). Crystallographic data for 3a are presented.

Physiological changes in Pinus sylvestris needles during early spring under sub-arctic conditions

Physiological condition of yellow and visually green Scots pine ( Pinus sylvestris L.) needles was followed in the Finnish sub-arctic during May and June 1996. The five greenest and five yellowest saplings were chosen for needle sampling at weekly intervals. The chlorophyll fluorescence, chlorophyll and water content, fine structure of the mesophyll cells and frost hardiness were determined at weekly intervals. Intracellular, extracellular and cell-membrane resistance were estimated by impedance spectroscopy and the distribution of free and bound water were determined by magnetic resonance imaging for needle samples collected on June 11, 1996. The chlorophyll a and b contents, the ratio between the maximum variable fluorescence and the maximal fluorescence yield ( F v/ F m) and the thickness of the grana stacks were higher in the green than yellow needles during the first three samplings in May. The yellow needles maintained a higher level of freezing-stress resistance compared to the green needles. The recovery of green color was accompanied by an increase in the chlorophyll a and b content, F v/ F m and the thickening of the grana stacks. The water content was slightly higher in the green than yellow needles in June. The water content still decreased even though the chlorophyll content of yellow needles began to increase and approached that of the green needles. Based on the magnetic resonance imaging, the water was distributed differently and in a more mobile form in the yellow than in the green needles. The extracellular resistance and the cell-membrane resistance were lower in yellow than green needles indicating impaired ability of yellow needles to maintain a high intracellular ion concentration. The results show that the yellow color of needles is an indication of a deeper state of photo-inhibition and slower deacclimation and is not directly related to the desiccation stress.

Solvothermal Synthesis, Crystal Structure Determination, and Properties of the Thioantimonate [Ph4P]2[Sb6S10

The reaction of elemental antimony with elemental sulfur and [Ph4P]Br in an aqueous solution of neopentanediamine under solvothermal conditions yields yellow needles of the new thioantimonate(III) [Ph4P]2[Sb6S10]. The structure consists of [Ph4P]+ cations and infinite one-dimensional anionic (Sb6S102−)n chains running along the crystallographic a axis. The chains are composed of 10-membered Sb5S5 rings with alternating Sb and S atoms and separated by the tetraphenylphosphonium cations. Upon heating the compound decomposes in two distinct steps, starting at about 100°C. The final product was identified by X-ray powder diffractometry as Sb2S3.

Crystal structures of [N(C4H9)4][NbCl4OAlCl3] and [N(C3H7)4][NbCl6

[N(C4H9)4][NbCl4OAlCl3] 1 crystallized after two months in form of yellow needles in a Schlenk-tube from a CH2Cl2/n-hexane solution containing equimolar amounts of [N(C4H9)4]Cl, NbCl5 and AlCl3. Yellow crystals of [N(C3H7)4][NbCl6] 2 yielded from the reaction of equimolar amounts of [N(C3H7)4]Cl and NbCl5 in the same solvent. The oxygen in 1 indicates a reaction of the educts with traces of water. Both compounds crystallize in the space group P21/n. (1: a=10.664(1)Å, b=14.177(1)Å, c=19.429(3)Å, β=90.01(1)°, Z=4; 2: a=11.678(2)Å, b=15.581(2)Å, c=11.769(1)Å, β=91.51(2)°, Z=4). 1 is characterized by [N(C4H9)4]+ cations and [NbCl4OAlCl3] units which are linked by chlorine bridges to dimeric anions. [NbCl4OAlCl3]- has a nearly linear Nb-O-Al bridge (bond angles 178.9(3)°) with a Nb-O bond length of 1.769(4) Å and a Al-O bond length of 1.771(5) Å. The structure of 2 contains [N(C3H7)4]+ cations and [NbCl6]- anions.

Terphenyl Ligand Stabilized Lead(II) Derivatives of Simple Organic Groups: Characterization of Pb(R)C6H3-2,6-Trip2(R = Me, t-Bu, or Ph; Trip = C6H2-2,4,6-i-Pr3), {Pb(μ-Br)C6H3-2,6-Trip2}2, py·Pb(Br)C6H3-2,6-Trip2(py = Pyridine), and the Bridged Plumbylyne Complex [{W(CO)4}2(μ-Br)(μ-PbC6H3-2,6-Trip2)

The reaction between 1 equiv of the sterically encumbered lithium terphenyl Et2O·LiC6H3-2,6-Trip2 and PbBr2 in diethyl ether afforded the organolead(II) halide compound {Pb(μ-Br)C6H3-2,6-Trip2}2 (1) as orange crystals. Treatment of 1 with a stoichiometric amount of pyridine (py) gave the complex py·Pb(Br)C6H3-2,6-Trip2 (2) as yellow needles. The addition of 1 equiv of methylmagnesium bromide, tert-butyllithium, or phenyllithium to 1 resulted in the diorganolead(II) compounds Pb(R)C6H3-2,6-Trip2 (R = Me, 3; t-Bu, 4; or Ph, 5) in good yield. The compounds 3 and 5 are the first stable, monomeric lead(II) derivatives involving the simplest alkyl and aryl groups Me and Ph. Reaction of 1 with W(CO)5THF did not yield the expected plumbylene complex (CO)5W{Pb(Br)C6H3-2,6-Trip2}. Instead, the bridged plumbylyne species [{W(CO)4}2(μ-Br)(μ-Pb-C6H3-2,6-Trip2)] (6) was obtained in low yield. All compounds were characterized by X-ray crystallography, 1H and 13C NMR, IR, and UV−vis spectroscopy. 207Pb NMR spectra of 3−5...

Polyoxomolybdate clusters and tetranuclear copper–organonitrogen complexes as building blocks for the design of three-dimensional oxide frameworks

The hydrothermal reaction of CuCl2·MoO, and 4,4′-bipyridylsulfide at 120 °C for 72 h yields yellow needles of {Cu(S-py2)}4Mo8O26]·2 H2O (MOXI-36). The structure is constructed from {Cu4(S-py2)4}4+ squares and [Mo8O26]4– clusters linked through CuO bonds into a three-dimensional assembly. The framework structure evolves from the linking of each {Cu4(S-py2)4}4+ cluster to four adjacent molybdate clusters, each of which in turn connects to four cationic clusters. Furthermore, the dimensions of the cationic building block, ca. 12.7 Å on an edge, are sufficient to accommodate an interior anionic cluster, as well as the four clusters linked to the exterior surface. This produces a two-fold interpenetrated framework in which each {Cu4(S-py4)}4+ ring acts as a host to a [Mo8O26]4– cluster. © 2000 Académie des sciences / Éditions scientifiques et médicales Elsevier SAShydrothermal synthesis / three-dimensional oxides / polyoxomolybdates / tetranuclear organonitrogen complexes / host–guest relationships / X-ray crystallography

Synthesis and crystal structure of a hexanuclear silver(I) cluster [Ag(Hmna)]6·4H2O (H2mna = 2-mercaptonicotinic acid) and a supramolecular gold(I) complex H[Au(Hmna)2] in the solid state, and their antimicrobial activities

2-Mercaptonicotinic acid (H2mna = 2-HS(C5H3N)CO2H) gave two types of silver(I) complexes by a reaction with Ag2O suspended in aqueous media; one was a water-insoluble, DMSO-soluble yellow powder [Ag(Hmna)]6·4H2O 1 formed under acidic conditions, and the other was a water-soluble, yellow powder {Na[Ag(mna)]·H2O}n 2 formed under alkaline conditions. These two complexes were interconverted on changing the acidity of the solution. Crystallization by vapor diffusion of the DMSO and aqueous solutions with external acetone gave pale yellow cubic crystals for 1 and pale yellow plate crystals for 2, but structure determination was successful only for 1. The molecular structure of 1 consists of a discrete, hexanuclear silver(I) cluster with the two silver(I) triangles linked by the mercaptonicotinate anions, the geometry around each silver(I) atom being constructed by one aromatic nitrogen atom and two μ-S atoms and the two weak silver(I)–silver(I) interactions. The corresponding gold(I) complex as a water-insoluble, DMSO-soluble yellow powder, H[Au(Hmna)2] 3, was prepared by treatment with aqueous HCl of Na3[Au(mna)2]·2H2O 4 which was obtained by a 1∶4∶8 molar ratio reaction of Na[AuCl4]·2H2O∶H2mna∶NaOH in aqueous solution. Complex 3 crystallized as yellow needle crystals by vapor diffusion of the DMSO solution with external acetone. Its crystal structure with a monomeric 2-co-ordinate AuS2 core shows a supramolecular arrangement by a π–π stacking interaction between two pyridine rings (face-to-face separation 3.42(2)–3.52(1) A) and, also, by two different hydrogen-bonding interactions; one formed between the carboxyl proton and aromatic nitrogen, and the other an unusual single-mode hydrogen bond between two twisted carboxyl groups. The complexes were also characterized by elemental analysis, TG/DTA, FT-IR, 1H and 13C NMR for 1–4, as well as 109Ag NMR for 2. Noteworthy antimicrobial activities for 1–4, evaluated by minimum inhibitory concentration, were observed.

InCrBr3: A Ternary Indium Bromide Containing Jahn−Teller Unstable Cr2+ and the Magnetic Structures of InCrBr3 and InFeBr3

Yellow needles of InCrBr3 are synthesized from molten InBr3 and elemental Cr at 450 °C. Its monoclinic crystal structure (a = 412.09(3) pm, b = 1500.6(1) pm, c = 937.65(6) pm, β = 94.386(6)°; P21/c...

Synthesis and Crystal Structure of Ternary SulfidesA3MS4withA=Na, Rb andM=Nb, Ta

The new ternary sulfides Na3MS4and Rb3MS4(M=Nb, Ta) were prepared from tantalum nitride or niobium powder in the respective alkali metal polysulfide melt. Both sodium sulfides crystallize in form of yellow (Nb) or yellow-orange (Ta) needles in the orthorhombic space groupFdd2 withZ=32 anda=27.3034(4) Å,b=28.4662(1) Å, andc=7.9642(1) Å,R/Rw=0.024/0.048 forM=Nb anda=27.2322(2) Å,b=28.4264(2) Å, andc=7.9634(6) Å,R/Rw=0.066/0.177 forM=Ta. The rubidium sulfides were obtained as yellow (Nb) and orange (Ta) crystals with irregular shape. They crystallize in the orthorhombic space groupPnmawithZ=4 anda=9.6109(6) Å,b=11.1013(7) Å, andc=9.6390(6) Å,R/Rw=0.030/0.072 forM=Nb anda=9.6084(5) Å,b=11.1067(6) Å, andc=9.6426(5) Å,R/Rw=0.031/0.070 forM=Ta. The structures of all four compounds are built by stacking isolatedMS3−4units with the alkali metal ions.

A New Isoflavone from Smilax glabra

A new isoflavone, 7,6’-dihydroxy-3’-methoxyisoflavone, has been isolated from the roots of Smilax glabra. The structure was determined by 2D-NMR techniques.

Shoot Feeding and Overwintering Behavior of Tomicus piniperda (Coleoptera: Scolytidae): Implications for Management and Regulation

An accurate and efficient survey method is essential to ensure the proper regulatory and management decisions for Tomicus piniperda (L.), a recent bark beetle invader in the United States. The life cycle and cryptic habits of T. piniperda make its detection difficult. T. piniperda adults feed in shoots in the summer, overwinter in the bark at the base of live pine trees, then oviposit into galleries in the bark of dead or dying trees. In 1992 and 1993, we characterized shoot damage and overwintering behavior of T. piniperda in the Great Lakes region of the United States. Shoot-feeding tunnels of T. piniperda were detectable in 7.4% of the shoots of Scots pine trees, Pinus sylvestris , sampled in northern Ohio in early October 1992. Adults of T. pinipenla fed primarily in the upper third of the tree crowns. Live T. piniperda adults were present in the majority of shoots that exhibited discolored needles and drooping shoots. However, many shoots with T. piniperda adults present exhibited no visible symptoms of attack. In early October, live adults were more common in tunnels constructed in current-year shoots than in 1-yr-old shoots. Scots, white ( P. strobes ), red ( P. resinosa ), and Austrian ( P. nigra ) pines attacked by T. piniperda developed yellow and brown needles, accompanied by drooping shoots only in Scots and white pines. In 1992 and 1993, the departure of T. piniperda adults from Scots pine shoots to their overwintering sites was correlated with subfreezing temperatures during latc October through December. Bolts of Scots, white, and Austrian pines were readily used by T. piniperda for overwintering sites, but bolts of blue spruce were not.

No consistent effects of ozone exposure for one growth season on levels of polyamines in Picea abies

It is well known that ozone is detrimental to plants, due to its action as a strong oxidant. Polyamines have been suggested as protecting against oxidative stress, and have been reported as being induced by ozone in plants. However, there is a paucity of data on tree species exposed to ozone for an extended period under field‐like conditions. In the present investigation, mature spruce clones were exposed to ozone (200 or 400 μg m−3 air) in open‐top chambers for an entire growth season at two localities in Norway, and levels of the polyamines, putrescine, spermidine and spermine were measured. No consistent effects of ozone fumigation were found on levels of any of the polyamines; not for two clones showing visible injury (yellow needles), and not for four apparently healthy clones. Thus, there was no correlation between sensitivity or tolerance to ozone and polyamine content. However, there were significant differences in polyamine contents between clones and the two localities of exposure.

Synthesis and polymerization of 7-alkoxycarbonyl-7,8,8-tricyanoquinodimethanes and 7,7-bis(alkoxycarbonyl)-8,8-dicyanoquinodimethanes

Attempts were made to prepare novel 7-alkoxycarbonyl-7,8,8-tricyanoquinodimethanes (ethoxy( 5a), isopropoxy( 5b), and tert-butoxy( 6c)), 7,7-bis(alkoxycarbonyl)-8,8-dicyanoquinodimethanes (ethoxy( 6a), isopropoxy( 6b), and tert-butoxy( 6c)), and 1-(2,2-dimethyl-1,3-dioxane-4,6-dione-5-ylidene)-4-(dicyanomethylene)-2,5-cyclohexadiene( 6d). 5c and 6d were obtained as yellow and orange needles, respectively, but 5a, 5b and 6a-c could not be isolated as crystals. Homopolymerizations of 5c and 6d and their copolymerizations with styrene were studied.

2-Ethyl-1-hydroxymethyl-4-trifluoromethyl-9H-carbazole

The general part of the experimental section [1] has been presented elsewhere.[...]

32] Chemical synthesis and properties of 7α-hydroxyriboflavin

The 7 α -hydroxyriboflavin (nekoflavin) is prepared from commercially available N -acetyl- o -toluidine. The procedures involving flavins should be performed under the light of a sodium lamp in a dark room to avoid photolysis. A silica gel plate [silica gel 70 plate (Wako) or silica gel 60 plate] and solvent system consisting of isoamyl alcohol–2–butanone–acetic acid–water (40 : 35 : 7:13 by weight) (ABAW) are used to monitor flavins eluted from the column. The spots of flavins are detected by black light. Several compounds involved in the synthesis of 7 α -hydroxyriboflavin are discussed— N -acetyl-4-chloro-2-methylaniline, 4-chloro-2-methylaniline hydrochloride, 4-chloro-2-methylbenzonitrile, 4-chloro-5-nitro-2-methylbenzonitrile, 4- D -ribitylamino-5-nitro-2-methylbenzonitrile, 4- D -ribitylamino-5-amino-2-methylbenzonitrile, 7-cyano-7-demethyl- D -riboflavin, 7-cyano-7-demethyl- D -riboflavin tetraacetate, and 7 α -amino- D -riboflavin. Several properties of 7 α -hydroxyriboflavin are also discussed in the chapter. This compound consists of fine yellow needles. In neutral medium the first and second absorption peaks are blue shifted as much as about 5 nm from those of riboflavin. The neutral solution has a yellow-greenish fluorescence.

Physiological, structural, and nutritional parameters of Norway spruce needles from declining forest stands in Austria

Decline phenomena in two spruce (Piceaabies (L.) Karst.) forests in different locations in Austria are described on a biochemical and ultrastructural level. Needles of declining trees (canopy state class 3 or 4, more than 40% needle loss, and visible needle chlorosis) are characterized by loss in chlorophylls, xanthophylls, and carotenes in older needles, with α-carotene and chlorophyll a showing strongest depressions. Total chlorophyll concentrations in visibly yellowed needles range below 1 mg•g−1 dry weight, whereas green needles contain more chlorophyll. All trees included in this study fit in one common model with respect to the pigment changes, suggesting that needle yellowing is a consequence of secondary reactions rather than an initial state of decline. Depressed α-carotene/β-carotene ratios are associated with electron-microscopically visible thylakoid reductions, and needles with lightened plastoglobuli exhibited higher neoxanthin contents. Apparently healthy trees (canopy state class 1 or 2, less than 40% needle loss) in the declining stands were used to correlate nutrient status and antioxidant responses (glutathione and ascorbic acid concentrations), respectively, versus chlorophyll contents to reveal primary contributors to decline symptoms. At one of the investigated sites chlorophyll concentrations are significantly correlated to nitrogen, calcium, and potassium contents of the needles. At the second site, correlations of glutathione levels to chlorophyll concentrations point to a considerable contribution of oxidative stresses to decline symptoms of the spruce stands in the second location, where nutritional factors do not seem to play a dominant role in the initial stages of the needle yellowing.

Crown ether complexation of PrCl 2+: Synthesis and structural characterisation of [PrCl 2(dibenzo-18-crown-6)(H 2O)][SbCl 6]·0.5MeOH·0.5MeCN

Treatment of PrCl 3(MeCN) 3.5 with antimony(V) chloride in the presence of dibenzo-18-crown-6 provided yellow needle crystals of [PrCl 2(dibenzo-18-crown-6)(H 2)][SbCl 6]·0.5MeOH·0.5MeCN following recrystallisation of the initial reaction product from boiling CH 3OH/CH 3CN (50:50). The ionic formulation was verified by X-ray crystallography. The cations have crystallographic m symmetry and the metal atoms are nine coordinate involving binding to all six crown oxygen atoms PrO crown 2.651(11)–2.668(10) Å, mean 2.658(10) Å, two chlorine atoms 2.740(4), 2.749(4) Å and a water molecule PrO H 2O 2.487(10) Å.

Chemistry of polyfunctional molecules—123 1. Reactions of BiBr 3, SbI 3 and AsI 3 with LiN(PPh 2) 2; X-ray structure of a cyclophosphazene salt containing arsenic(I)

BiBr 3 or SbI 3 react at 20°C with LiN(PPh 2) 2 ( 1) to give elementary Bi or Sb and the PP coupled phosphazene ligand Ph 2PNPPh 2PPh 2NPPh 2 ( 2). The reaction of AsI 3 with 1 at room temperature formed yellow needles of the eight-membered heterocycle ▪ ( 3), whereas AsI 3 interacted at 80°C with 1 in the molar ratio of 1:3 to give elementary arsenic and 2. Treatment of AsI 3 and 1 at 20°C in a 1:2 stoichiometry yielded the seven-membered, cyclic arsenium(I) salt ▪ I·4THF ( 5·4THF), which was characterized by elemental analysis, conductivity, mass, IR and NMR spectroscopy and single-crystal X-ray structural analysis.

Simple and Excellent Preparation of Polymorphic Crystals of 4,5-Bis(4-Methoxyphenyl)-2-(3-Nitrophenyl)-1H-Imidazole

Abstract The title imidazole 1 forms inclusion complexes with ethyl acetate, tert-BuOH, and benzene. The complexes lost their guest molecule to give polymorphic crystals A, B, C and D in a pure state. A is red plates, B is yellow needles, C is pale yellow silky needles and D is light yellow cottony needles. The polymorphic crystal turns to the other one when the crystal contacts with organic vapor. The reactivity decreased with B>D>C>A. Structure and reactivity of the polymorphic crystals are discussed on the type of hydrogen bonding and on molecular arrangements in crystals.