288 research outputs found
Synthesis and crystal structure of the first 6a-thiathiophthen metal complex [Mo(CO)_5PPh_(2]2)(µ-C_5H_2S_3)
The first 6a-thiathiophthen metal complex was prepared by treating M(CO_)5[PPh_2CS_2CH_2C≡CH] with a catalytic amount of secondary amine or tertiary amine; the structure of the 6a-thiathiophthen molybdenum complex is confirmed by an X-ray diffraction analysis
Synthesis, structure and electrochemical properties of tris-picolinate complexes of rhodium and iridium
Reaction of picolinic acid (Hpic) with rhodium trichloride or iridium trichloride affords tris-picolinate complexes of the type [M(pic)3] (M = Rh, Ir). The crystal structures of both complexes have been determined by X-ray diffraction. In both complexes, the picolinate ligands are coordinated to the metal center as bidentate N,O-donors forming five-membered chelate rings. There is one molecule of water of crystallization per molecule of each [M(pic)3] complex. The water molecule is hydrogen bonded to the carboxylate fragments of two adjacent [M(pic)3] molecules and thus acts as a bridge between the individual complex molecules. The complexes are diamagnetic (low-spin d6, S = 0) and show intense MLCT transitions in the visible region. Cyclic voltammetry on the [M(pic)3] complexes shows a M(III)-M(IV) oxidation near 1.0 V versus SCE and a ligand-centered reductive response near -1.0 V versus SCE
trans-Bromido(pyrimidinyl-κC 2)bis(triphenylphosphane-κP)palladium(II)
In the title complex, [PdBr(C4H3N2)(C18H15P)2], the geometry around the PdII atom is distorted square-planar with the PdII atom displaced by 0.0150 (5) Å from the least-squares BrP2C plane. Two PPh3 ligands are in trans positions [P—Pd—P = 176.743 (17)°], while the pyrimidinyl ligand and Br atom are trans to one another [C—Pd—Br = 176.56 (5)°]. Structural parameters from NMR, IR and mass spectra are in agreement with the crystal structure of the title compound
[(Pyrrolidin-1-yl)carbothioylsulfanyl]methyl pyrrolidine-1-carbodithioate
The title compound, C11H18N2S4, was unexpectedly obtained during studies on the reactivity of the complex tris(acac-κ2
O,O′)gallium(III) (acac is acetylacetonate) with C4H8NCS2H in dichloromethane. The title compound shows disordered two pyrrolidine rings with major and minor occupancies of 0.546 (4) and 0.454 (4). Two (pyrrolidin-1-yl)carbothioylsulfanyl units are linked together through a methylene C atom and weak C—H⋯S interactions are found
Bis(carbonyl-κC)(N,N-dimethylthiocarbamoyl-κ2 C,S)(pyridine-2-thiolato-κ2 N,S)(triphenylphosphine-κP)molybdenum(II)
There are two independent molecules with similar configurations in the title complex, [Mo(C3H6NS)(C5H4NS)(C18H15P)(CO)2]. The geometry around the metal atom is that of a capped octahedron. The thiocabamoyl and pyridine-2-thiolate ligands coordinate to the molybdenum metal center through the C and S atoms, and N and S atoms, respectively. NMR, IR and MS analyses are in agreement with the structure of the title compound
trans-Bromido(pyrimidinyl-κC 5)bis(triphenylphosphane-κP)palladium(II)
In the title complex, [PdBr(C4H3N2)(C18H15P)2], the geometry around the Pd atom is distorted square-planar with the Pd atom displaced by 0.0334 (14) Å from the BrP2C plane. The two Ph3P ligands are in trans positions, defining a P—Pd—P angle of 171.78 (5)°, while the pyrimidinyl and bromide ligands are trans to each other [C—Pd—Br = 174.63 (14)°]
Role of the Diphosphine Chelate in Emissive, Charge-Neutral Iridium(III) Complexes
A class of neutral tris-bidentate Ir(III) metal complexes incorporating a diphosphine as a chelate is prepared and characterized here for the first time. Treatment of [Ir(dppb)(tht)Cl3] (1) with fppzH afforded the dichloride complexes, trans-(Cl,Cl)[Ir(dppb)(fppz)Cl2] (2) and cis-(Cl,Cl)[Ir(dppb)(fppz)Cl2] (3). The reaction of 3 with the dianionic chelate precursor bipzH2 or mepzH2, in DMF gave the complex [Ir(dppb)(fppz)(bipz)] (4) or [Ir(dppb)(fppz)(mepz)] (5), respectively. In contrast, a hydride complex [Ir(dppb)(fppz)(bipzH)H] (6) was isolated instead of 4 in protic solvent, namely: DGME. All complexes 2 - 6 are luminescent in powder forms and thin films where the dichlorides (2, 3) emit with maxima at 590-627 nm (orange) and quantum yields (Q.Y.s) up to 90% whereas the tris-bidentate (4, 5) and hydride (6) complexes emit at 455-458 nm (blue) with Q.Y.s up to 70%. Hybrid TD-DFT calculations showed considerable MLCT contribution to the orange-emitting 2 and 3 but substantial ligand-centered 3ππ* transition character in the blue-emitting 4 - 6. The dppb does not participate to these radiative transitions in 4 - 6, but it provides the rigidity and steric bulk needed to promote the luminescence by suppressing the self-quenching in the solid state. Fabrication of an OLED with dopant 5 gave a deep blue CIE chromaticity of (0.16, 0.15). Superior blue emitters, which are vital in OLED applications, may be found in other neutral Ir(III) complexes containing phosphine chelates
Correction of rotational distortion for catheter-based en face OCT and OCT angiography
We demonstrate a computationally efficient method for correcting the nonuniform rotational distortion (NURD) in catheter-based imaging systems to improve endoscopic en face optical coherence tomography (OCT) and OCT angiography. The method performs nonrigid registration using fiducial markers on the catheter to correct rotational speed variations. Algorithm performance is investigated with an ultrahigh-speed endoscopic OCT system and micromotor catheter. Scan nonuniformity is quantitatively characterized, and artifacts from rotational speed variations are significantly reduced. Furthermore, we present endoscopic en face OCT and OCT angiography images of human gastrointestinal tract in vivo to demonstrate the image quality improvement using the correction algorithm.National Institutes of Health (U.S.) (R01-EY011289-26)National Institutes of Health (U.S.) (R44-EY022864-01)National Institutes of Health (U.S.) (R01-CA075289-16)National Institutes of Health (U.S.) (R44-CA101067-05)National Institutes of Health (U.S.) (R01-CA178636-02)United States. Air Force Office of Scientific Research (Contract FA9550-10-1-0063)United States. Air Force Office of Scientific Research (Contract FA9550-12-1-0499
Bis(morpholin-4-ium) tetrachloridocobalt(II)
The title compound, (C4H10NO)2[CoCl4], is an ionic compound consisting of two protonated tetrahydro-1,4-oxazine (morpholine) cations and a [CoCl4]2− dianion. The CoII ion is in a tetrahedral coordination geometry. The cations exhibit chair-shaped conformations. A three-dimensional supramolecular architecture is formed through N—H⋯Cl and C—H⋯Cl hydrogen bonds between the dianions and the cations
Dicarbonylchlorido(phenoxythiocarbonyl-κ2 C,S)bis(triphenylphosphane-κP)molybdenum(II)
In the title complex, [Mo(C7H5OS)Cl(C18H15P)2(CO)2], the geometry around the metal atom is a capped octahedron. The phenoxythiocarbonyl ligand coordinates the MoII atom through the C and S atoms. A one-dimensional structure is formed by π–π intermolecular interactions and a supramolecular aggregation is determined by intermolecular C—H⋯O, C—H⋯Cl, C—H⋯π(arene) hydrogen bonds and CO⋯π(arene) interactions [O⋯centroid distances = 3.485 (4) and 3.722 (3) Å]
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