A Turn-on Fluorescent Chemosensor for Zn(2+) Based on Quinoline in Aqueous Media.

A simple "off-on fluorescence type" chemosensor 1 3-((2-(dimethylamino)ethyl)amino)-N-(quinolin-8-yl)propanamide has been synthesized for Zn(2+). The receptor 1 comprises the quinoline moiety as fluorophore and the N,N(')-dimethylethane-1,2-diamine as a binding site. 1 showed a remarkable fluorescence enhancement in the presence of Zn(2+) in aqueous solution. Importantly, the chemosensor 1 could be used to detect and quantify Zn(2+) in water samples. In particular, this chemosensor could clearly distinguish Zn(2+) from Cd(2+). The binding properties of 1 with Zn(2+) ions were investigated by UV-vis, fluorescence, electrospray ionization mass spectroscopy and (1)H NMR titration.

Bis(µ-3-carb-oxy-2-hy-droxy-propane-1,2-dicarboxyl-ato)bis(diaquazinc)-1,2-bis-(pyridin-4-yl)ethene-water (1/1/2).

The asymmetric unit of the title compound, [Zn(2)(C(6)H(6)O(7))(2)(H(2)O)(4)]·C(12)H(10)N(2)·2H(2)O, comprises half of a centrosymmetric complex dimer, half of a 1,2-bis-(pyridin-4-yl)ethene mol-ecule, which lies across an inversion centre, and one lattice water mol-ecule. Carboxyl-ate groups of two dianionic citrate ligands bridge two Zn(II) ions to give the cyclic dimer, with each Zn(II) ion coordinated by four O atoms from the chelating citrate ligand (one hy-droxy and three carboxyl-ate, with one bridging) and two water O atoms, forming a distorted octa-hedral environment [Zn-O = 2.040 (3)-2.244 (3) Å]. In the crystal, O-H⋯O and O-H⋯N hydrogen bonds involving hy-droxy groups and both coordinating and lattice water mol-ecules link the dimers to give a three-dimensional framework structure.

Bis(µ-2-carboxymethyl-2-hydroxy-butane-dioato)bis-[diaqua-manganese(II)]-1,2-bis-(pyridin-4-yl)ethane-water (1/1/2).

The asymmetric unit of the title compound, [Mn(2)(C(6)H(6)O(7))(2)(H(2)O)(4)]·C(12)H(12)N(2)·2H(2)O, comprises half of a centrosymmetric dimer, half of a 1,2-bis-(pyridin-4-yl)ethane and one water mol-ecule. Two citrate ligands bridge two Mn(II) ions, the Mn(II) ion being coordinated by four O atoms from the citrate(2-) ligands and two water O atoms, forming a distorted octa-hedral environment. In the crystal, O-H⋯O hydrogen bonds link the centrosymmetric dimers and lattice water mol-ecules into a three-dimensional structure which is further stabilized by inter-molecular π-π inter-actions [centroid-centroid distance = 3.792 (2) Å].

Bis(µ-2-carb-oxy-methyl-2-hy-droxy-butane-dioato)bis-[diaqua-manganese(II)]-1,2-bis-(pyridin-4-yl)ethene-water (1/1/2).

The asymmetric unit of the title compound, [Mn2(C6H6O7)2(H2O)4]·C12H10N2·2H2O, contains half of the centrosymmetric Mn complex dimer, half of a 1,2-bis-(pyridin-4-yl)ethene mol-ecule, which lies across an inversion center, and one water mol-ecule. Two citrate ligands bridge two Mn(II) ions, and each Mn(II) atom is coordinated by four O atoms from the citrate ligands (one from hy-droxy and three from carboxyl-ate groups) and two water O atoms, forming a distorted octa-hedral environment. In the crystal, O-H⋯O and O-H⋯N hydrogen bonds link the centrosymmetric dimers and lattice water mol-ecules into a three-dimensional structure which is further stabilized by inter-molecular π-π inter-actions [centroid-centroid distance = 3.959 (2) Å]. Weak C-H⋯O hydrogen bonding interactions are also observed.

Morphology of foliar trichomes of the Chinese cork oak Quercus variabilis by electron microscopy and three-dimensional surface profiling.

Morphology of foliar trichomes was analyzed in Quercus variabilis by electron microscopy and three-dimensional surface profiling. Leaves from suppressed or dominant sprouts of the oak species were collected after a forest fire to unravel the effects of the disturbance factor on sprouting of the oak species. Scanning electron microscopy revealed two types of trichomes depending on the leaf surface. The trichomes on the adaxial surface were branched and constricted, and possessed a single row of thin-walled cells with a collapsed morphology (glandular branched uniseriate trichomes). Meanwhile, the trichomes on the abaxial surface were star-shaped, unfused with each other, and had 6 to 10 rays (nonglandular simple stellate trichomes). An apparent proliferation of trichomes was evident on the adaxial surface of the dominant sprouts. Uniseriate trichomes could be discernable as an elevation from the surface by white light scanning interferometry. By transmission electron microscopy, thin and convoluted cell wall, degenerated cytoplasm, and a single row of cells were characteristic of the trichomes on the adaxial surface. The thick cell walls of the mature trichomes on the abaxial surface represented the nonglandular nature. This is the first report on the morphological and ultrastructural characterization of foliar trichomes of the oak species.

catena-Poly[[tetra-aqua-[trans-1,2-bis-(4-pyrid-yl)ethene-κN:N']nickel(II)] dinitrate].

In the title compound, {[Ni(C(12)H(10)N(2))(H(2)O)(4)](NO(3))(2)}(n), the Ni(II) ion, lying on a crystallographic inversion center, has a distorted octa-hedral coordination sphere comprising four water ligands and two N-atom donors from the trans-related 1,2-bis-(4-pyrid-yl)ethene ligands, which also have crystallographic inversion symmetry. These ligands bridge the Ni(II) complex units, forming chains extending along the [110] and [[Formula: see text]10] directions. The nitrate counter-anions stabilize the crystal structure through water-nitrate O-H⋯O hydrogen bonds.

catena-Poly[[bis-(2,4-dichloro-benzoato)bis-(methanol-κO)cobalt(II)]-µ-4,4'-bipyridine-κN:N'].

In the title compound, [Co(C(7)H(3)Cl(2)O(2))(2)(C(10)H(8)N(2))(CH(3)OH)(2)](n), the Co(II) ion lies on a twofold rotation axis and is in a slightly distorted octa-hedral CdO(4)N(2) environment, formed by two O atoms from monodentate dichloro-benzoate ligands, two O atoms from methanol ligands, and two N atoms from trans-related 4,4'-bipyridine ligands. The bipyridine ligands also lies on a twofold rotation axis and bridge the Co(II) ions, forming chains extending along [010]. An intra-chain O-H⋯O hydrogen bond is observed.

Bis(methanol-κO)bis-(quinoline-2-carboxyl-ato-κN,O)nickel(II).

In the title complex, [Ni(C(10)H(6)NO(2))(2)(CH(3)OH)(2)], the Ni(II) ion lies on an inversion center and is coordinated by two quinoline-2-carboxyl-ate ligands in the equatorial sites and two axial methanol ligands, forming a distorted octa-hedral environment. In the crystal, mol-ecules are linked via O-H⋯O hydrogen bonds into a two-dimensional network parallel to (10[Formula: see text]).

Bis(di-2-pyridyl-methane-diol-κN,O,N')nickel(II) dibenzoate.

The title compound, [Ni(C(11)H(10)N(2)O(2))(2)](C(7)H(5)O(2))(2), consists of an Ni(II) ion coordinated by two tridentate chelating (2-py)(2)C(OH)(2) ligands (py is pyrid-yl) and two benzoate anions. The Ni(II) ion is located on a twofold rotation axis, and its geometry is distorted octa-hedral. The gem-diol ligand (2-py)(2)C(OH)(2) adopts an η(1):η(1):η(1) coordination mode. There are O-H⋯O hydrogen bonds between the gem-diol ligands and benzoate anions.

Dibenzoatobis[3-(pyrrol-1-ylmeth-yl)pyridine]-zinc(II).

In the title compound, [Zn(C(7)H(5)O(2))(2)(C(10)H(10)N(2))(2)], the Zn(II) ion, located on a twofold axis, is coordinated by two N atoms from two 3-(pyrrol-1-ylmeth-yl)pyridine ligands and two O atoms from two benzoate ligands in a distorted tetra-hedral geometry. The pyridine and the pyrrole rings are nearly perpendicular to each other, making a dihedral angle of 84.83 (7)°.

catena-Poly[[bis-(2-hydr-oxy-2-phenyl-acetato-κO,O)zinc(II)]-µ-1,2-di-4-pyridylethane-κN:N'].

The title compound, [Zn(C(8)H(6)O(3))(2)(C(12)H(12)N(2))](n), consists of [Zn(Hopa)(2)] (H(2)opa = 2-hydr-oxy-2-phenyl-acetic acid or mandelic acid) units bridged by 1,2-di-4-pyridylethane (bpe) ligands, forming a polymeric chain developing parallel to the b axis. The bridging bpe ligand is arranged around a twofold axis passing through the middle of the ethane C-C bond. The geometry around the Zn(II) ion is distorted octa-hedral, constructed by four O atoms from two Hopa(-) ligands and two N atoms from two bridging bpe ligands. O-H⋯O hydrogen bonds link the chains, forming a three-dimensional network.

Tetra-µ-benzoato-bis-{[4-(pyrrolidin-1-yl)pyridine]zinc(II)}.

The central part of the title centrosymmetric dinuclear complex, [Zn(2)(C(7)H(5)O(2))(4)(C(9)H(12)N(2))(2)], has a paddle-wheel conformation with four benzoate ligands bridging two symmetry-related Zn(II) ions. The distorted square-pyramidal coordination environment around the Zn(II) ion is completed by an N atom from a 4-(pyrrolidin-1-yl)pyridine ligand. The Zn⋯Zn separation of 2.9826 (12) Šdoes not represent a formal direct metal-metal bond. The Zn(II) ion is displaced by 0.381 (1) Šfrom the mean plane of the four basal O atoms. Two of the C atoms of the pyrrolidine ring are disordered over two sites with refined occupancies of 0.53 (2) and 0.47 (2).

A neutral cubane with a Zn(4)O(4) core: tetra-benzoato-tetra-kis(µ(3)-hydroxydi-2-pyridylmethano-lato)tetra-zinc(II)-acetone-methanol (1/2/1).

In the title compound, [Zn(4)(C(11)H(9)N(2)O(2))(4)(C(7)H(5)O(2))(4)]·2(CH(3))(2)CO·CH(3)OH, the tetra-nuclear mol-ecule lies on a fourfold inversion axis. Zn(II) ions and µ(3)-O atoms in the cubane core occupy alternating vertices, forming two inter-penetrating tetra-hedra. Each Zn(II) ion is further coordinated by two N atoms from two different (py)(2)C(OH)O ligands (py is pyrid-yl) and one O atom from a monodentate benzoate ligand, forming a distorted octa-hedral environment. The (py)(2)C(OH)O ligand acts in an η(1):η(3):η(1):µ(3) manner, forming two five-membered ZnNCCO chelating rings with two different Zn(II) atoms sharing a common C-O bond, and an alkoxide-type bond to a third Zn(II) ion. There are four symmetry-related intra-molecular O-H⋯O hydrogen bonds between the two types of ligands. In the asymmetric unit, there is a half-occupancy acetone solvent mol-ecule and a half-occupancy methanol solvent molecule that lies on a twofold rotation axis.

Tetra-µ-benzoato-bis-[(3-methyl-quinoline)copper(II)](Cu-Cu).

In the title compound, [Cu(2)(C(7)H(5)O(2))(4)(C(10)H(9)N)(2)], the paddle-wheel-type dinuclear complex mol-ecule contains four bridging benzoate groups and two terminal 3-methyl-quinoline ligands. The asymmetric unit contains one and a half mol-ecules with a total of three independent Cu atoms; there is an inversion center at the mid-point of the Cu⋯Cu bond in one molecule. The octa-hedral coordination of each Cu atom, with four O atoms in the equatorial plane, is completed by an N atom of a 3-methyl-quinoline ligand [Cu-N = 2.190 (4)-2.203 (3) Å] and by another Cu atom [Cu⋯Cu = 2.667 (1) and 2.6703 (7) Å]. The Cu atoms are all ca 0.22 Šout of the plane of the four bonded O atoms.

Bis(2,6-dimethyl-pyrazine-κN)diiodidozinc(II).

In the title compound, [ZnI(2)(C(6)H(8)N(2))(2)], the Zn(II) ion is coordinated by two iodide anions and two N atoms from 2,6-dimethyl-pyrazine in a distorted tetra-hedral geometry.

Tetra-µ-benzoato-bis-[(6-methyl-quino-line)-copper(II)].

In the title compound, [Cu(2)(C(7)H(5)O(2))(4)(C(10)H(9)N)(2)], the paddle-wheel-type dinuclear complex is constructed by four bridging benzoate groups and two terminal 6-methyl-quinoline ligands. The asymmetric unit contains one-half of the whole mol-ecule, and there is an inversion center at the mid-point of the Cu⋯Cu bond. The octa-hedral coordination of each Cu atom, with four O atoms in the equatorial plane, is completed by the N atom of the 6-methyl-quinoline mol-ecule [Cu-N = 2.212 (2) Å] and by another Cu atom [Cu⋯Cu = 2.6939 (13) Å]. The Cu atom lies 0.234 Šout of the plane of the four O atoms. The molecular packing is stabilized by one intramolecular C-H⋯O as well as C-H⋯π and π-π interactions.

Alleviation of Cd toxicity by composted sewage sludge in Cd-treated Schmidt birch (Betula schmidtii) seedlings.

We investigated alleviation of Cd toxicity and changes in the physiological characteristics of Betula schmidtii seedlings following application of composted sewage sludge to Cd-treated plants. Plants were grown under four test conditions: control, Cd treatment, sludge amendment, and Cd treatment with sludge amendment. B. schmidtii treated with Cd only accumulated the greatest amount of Cd in the leaves, but absorbed Cd was also highly concentrated in the roots. In contrast, Cd concentrations in the Cd and sludge amendment treated seedlings were the lowest in the roots. Since sludge amendment increased the growth of seedlings, it may have alleviated toxicity by dilution of Cd. Additionally, the absorbed Cd was more widely distributed since it was transported from the roots and accumulated in the stems and leaves of Cd and sludge treated plants. Cd treatment inhibited the growth and physiological functions of B. schmidtii seedlings, but sludge amendment compensated for these effects and improved growth and physiological functions in both Cd-treated and control plants. SOD activity in the leaves of seedlings was increased in the Cd-treated plants, but not in the Cd and sludge amendment treated seedlings. In conclusion, alleviation of Cd toxicity in response to sludge amendment may be related to a dilution effect, in which the Cd concentration in the tissues was effectively lowered by the improved growth performance of the seedlings.

Seawater spray injury to Quercus acutissima leaves: crystal deposition, stomatal clogging, and chloroplast degeneration.

Effects of seawater spray on leaf structure were investigated in Quercus acutissima by electron microscopy and X-ray microanalysis. Two-year-old seedlings of Q. acutissima were sprayed with seawater and kept in a greenhouse maintained at 25°C. The most recognizable symptoms of seawater-sprayed seedlings included leaf necrosis, crystal deposition, stomatal clogging, and chloroplast degeneration. Field emission scanning electron microscopy revealed that the leaf surface was covered with additional layers of remnants of seawater spray. Composed of sodium and chloride, cube-shaped crystals (halite) were prevalently found on trichomes and epidermis, and formed aggregates. Meanwhile, wedge-shaped crystals were deposited on epidermis and consisted of calcium and sulfur. As a result of stomatal clogging by crystal deposition on the abaxial surface, it was conceivable that plant respiration became severely hampered. Transmission electron microscopy showed degenerated cytoplasm of seawater-sprayed leaves. It was common to observe severe plasmolysis and disrupted chloroplasts with a reduced number of thylakoids in grana. These results indicate that foliar applications of seawater were sufficient to induce necrosis of Q. acutissima seedlings as an abiotic disturbance factor.

3D surface profiling and high resolution imaging for refining the florin rings and epicuticular wax crystals of Pinus koraiensis needles.

3D surface profiling and high resolution imaging were performed to refine the Florin rings and epicuticular wax crystals of Pinus koraiensis needles. Needles were collected from four-year-old seedlings and air-dried for surface observations. Field emission scanning electron microscopy revealed that stomata were found on the abaxial (lower) surface of needles. Measured as ca. 40 µm long, they were largely elliptical or oval-shaped. Epicuticular wax crystals were present in the epistomatal chambers as well as on the surrounding epidermis. Rodlets were prevalently found on the stomatal bands and furrows as well as within the epistomatal chambers. The presence of wax tubules was ascertained by the distinct terminal openings at their ends. The occurrence of wax ridges was evident on the epidermis near the saw-tooth margins (nonstomatal areas). No distinct wax ridges were detected on the dewaxed needles. Raised Florin rings were distinct on the stomata. White light scanning interferometry showed that the diameter and width of stomata were ca. 44.02 ± 3.33 µm and 32.10 ± 3.30 µm, respectively. Measured from the neighboring epidermis to the stomatal aperture, the mean height of the stoma reached ca. 6.23 ± 1.28 µm. Focus variation metrology allowed measuring the mean elevation angle of the stoma, reaching ca. 41.41 ± 11.25°. This is the first report on a novel approach to the establishment of quantitative criteria of Florin ring classification by nontactile 3D surface profiling beyond the previous qualitative descriptions of Florin rings of coniferous species.

Three-dimensional surface topography of the needle stomatal complexes of Pinus rigida and its hybrid species by complementary microscopy.

Three-dimensional surface topography of needle stomatal complexes was investigated in Pinus rigida, Pinus taeda, and their interspecific hybrid Pinus rigitaeda. The stomatal complexes of P. rigida appeared to be sunken and ca. 15 microm deep by white light scanning interferometry. Stomatal grooves were evident in P. taeda along the stomata and amounted to ca. 5 microm deep. The centers of stomata maintained the similar height to the stomatal apertures. Meanwhile, the stomatal complexes of P. rigitaeda (ca. 15 microm deep) were characterized by distinct stomatal grooves and sunken stomatal chambers. In addition, field emission scanning electron microscopy revealed the stomatal complexes of P. rigida partially filled with epicuticular waxes. It was common to observe distinct stomatal grooves and chamber-filled stomata on P. taeda needles. The stomatal complexes of P. rigitaeda had the distinct stomatal grooves and were partially filled with wax tubules and rodlets. Surface roughness measurements of stomatal complexes showed higher levels of roughness from P. rigida and P. rigitaeda than that from P. taeda. These results indicate that the hybrid species P. rigitaeda showed intermediacy in surface characteristics between the parent species, suggesting the genetic control of needle stomatal complexes in the hybrid species.