Although zeolites and related materials combine nanoporosity with high thermal stability, they are difficult to modify or derivatize in a systematic way. A highly porous metal coordination polymer [Cu3(TMA)2(H2O)3]n (where TMA is benzene-1,3,5-tricarboxylate) was formed in 80 percent yield. It has interconnected [Cu2(O2CR)4] units (where R is an aromatic ring), which create a three-dimensional system of channels with a pore size of 1 nanometer and an accessible porosity of about 40 percent in the solid. Unlike zeolites, the channel linings can be chemically functionalized; for example, the aqua ligands can be replaced by pyridines. Thermal gravimetric analysis and high-temperature single-crystal diffractometry indicate that the framework is stable up to 240 degreesC.
The synthesis and characterization of a novel series of tetrachlorocuprate salts, based on
N-alkylpyridinium cations ([Cn−Py]+), are described. The [Cn−Py]2[CuCl4] salts (n = 6, 9−18)
were found to be crystalline solids except for the short-chain homologues (n = 6, 9, 10),
which were obtained as viscous liquids. X-ray powder diffraction measurements showed that
in the crystalline state the ionic species give rise to layered structures. An X-ray crystal
structure study of [C15−Py]2[CuCl4] also confirmed the lamellar packing and revealed the
monolayer type of organization with strong interdigitation and canting of N-alkyl chains.
Most solid salts (n ≥ 12) are thermotropic liquid crystals, with hexagonal columnar, cubic,
and smectic phases appearing in the order of increasing chain length and/or temperature.
This unique phase behavior has been undoubtedly proved by optical, calorimetric, and
diffractometric techniques. The details of the structural organization in both the columnar
and cubic phases are not entirely defined yet.
Conditions are reported for the facile, high-yielding coupling of acyl chlorides with terminal alkynes in a reaction involving palladium and copper iodide; the reaction is tolerant of a wide variety of acyl chlorides and terminal alkynes and provides a convenient one-pot route to acetylenic ketones.
The homoleptic high-nuclearity platinum−copper acetylide complex of stoichiometry [PtCu2(C⋮CPh)4] crystallizes in at least three different polymorphic forms. Dark violet-green
crystals with metallic reflectance have been shown by an X-ray diffraction study to be formed
by discrete trimers of an hexanuclear octahedral cluster unit {[Pt2Cu4(C⋮CPh)8]}3 stabilized
by two unsupported Pt−Pt interactions [2.995(1) Å]. The photoluminescence behavior of this
complex which is dramatically influenced by strong axial Pt···Pt interactions either in solid
state or in solution (CH2Cl2 298, 77 K) has been studied.
Angle-dependent magnetoresistance measurements are used to determine the isotropic and anisotropic components of the transport scattering rate in overdoped Tl2Ba2CuO 6+δ for a range of Tc values between 15K and 35K. The size of the anisotropic scattering term is found to scale linearly with Tc, establishing a link between the superconducting and normal state physics. Comparison with results from angle resolved photoemission spectroscopy indicates that the transport and quasiparticle lifetimes are distinct.PACS numbers: 74.72. Jt, Understanding the normal state is regarded as a key step in resolving the problem of high temperature superconductivity (HTSC) yet establishing any clear correlation between the two has proved difficult. Most empirical correlations to date, such as the Uemura plot [1] and the linear scaling of the magnetic resonance mode energy with T c [2], are associated with the superconductivity. Homes' law, linking T c with the product of the superfluid density and the dc conductivity (at T c ) [3], is a rare example of a correlation linking the two states, though this also could be viewed as a consequence of superconducting (SC) gap formation rather than a normal state property [4]. Transport properties, particularly for current in-plane, appear very much tied to the T c parabola (for a review see [4]) but any direct correlation between transport and superconductivity has not yet been found. Finally, the precise doping dependence of the pseudogap and its relation to T c remains a controversy [5].Here we identify a new correlation between the normal and superconducting states using a bulk transport probe, namely interlayer angle-dependent magnetoresistance (ADMR).[6] ADMR have provided detailed Fermi surface (FS) information for a variety of one-and twodimensional (2D) metals [7,8,9]. Recently the technique was extended to incorporate basal-plane anisotropy and to reveal the temperature T -and momentum (k-) dependence of the scattering rate Γ(T ,k) in heavily overdoped (OD) Tl 2 Ba 2 CuO 6+δ (Tl2201) [10]. There Γ(T ,k) was found to consist of two components, one isotropic and quadratic in T , the other anisotropic, maximal near the saddle points at (π, 0) and proportional to T .In this Letter, ADMR measurements at T = 40K and magnetic field µ 0 H = 45Tesla are compared for a number of OD Tl2201 crystals with T c values between 15K and 35K. The strength of the anisotropic scattering extracted from the analysis is found to scale linearly with T c , appearing to extrapolate to zero at the doping level where superconductivity vanishes. This finding implies that the anisotropic scattering mechanism is intimately related to the mechanism of HTSC. In marked contrast to recent results from angle resolved photoemission spectroscopy (ARPES) [11,12], no sign reversal of the anisotropy in the quasiparticle lifetime is inferred. Finally our results shed new light on the doping evolution of both ρ ab (T ) and R H (T ) in OD cuprates.For this study a total of six tetragonal self-flux grown crystals (typical dime...
The reaction between [Co(PMe3)4] and B2(4-Mecat)2 (4-Mecat = 1,2-O2-4-MeC6H3) or between [Co(PMe2Ph)4] and B2(cat)2 (cat = 1,2-O2C6H4) affords the paramagnetic Co(II) bisboryl complexes [Co(PMe3)3[B(4-Mecat)]2] and [Co(PMe2Ph)3{B(cat)]2] respectively, both of which have been structurally characterised. ESR data and preliminary diboration and boryl transfer reactivity studies are also presented. The reaction between [CoMe(PMe3)4] and B2(cat)2 affords the Co(I) monoboryl complex [Co(PMe3)4[B(cat)]].
Crystal tuning: Organic molecules can be xenophobic, preferring to crystallize with their own kind. Though useful for purification, this precludes the tuning of crystal properties by doping or mixing. Nanoporous steroids provide an exception, as their channels can accept a variety of termini (hexagons and spheres). The steroids can be cocrystallized in any ratio to give a wide range of chiral, potentially porous crystalline materials.
The synthesis and properties of two novel platinum-thallium alkynyl complexes, [trans,cis,cis-PtTl 2 (C 6 F 5 ) 2 (CtCPh) 2 ], 1 (X-ray), with two Tl(I)-Pt(II) bonds, and [cis-PtTlLi(C 6 F 5 ) 2 -(CtCPh) 2 ], 2, which is an ionic conductor in the solid state, are presented. Both complexes exhibit a strong yellow luminescence, which is attributed, on the basis of TD-DFT calculations, to charge transfer from Tl-Pt-Tl (1) or Tl-Pt (2) units to the platinum metal fragments.
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