31 research outputs found
A solvent-free regioselective iodination route of ortho-carboranes
No full textTetraiodo-ortho-carborane based X-ray contrast agents can be readily prepared in a high yield, fast, clean, regioselective fashion by a solvent-free reaction of ortho-carboranes with iodine in sealed tubes.Vaca Puga, A.; Teixidor, F.; Kivekas, R.; Sillanpaa, R.; Viñas, C. (2006). A solvent-free regioselective iodination route of ortho-carboranes. Dalton Transactions. (41):4884-4885. doi:10.1039/b612465hS488448854
Synthesis of quadruped-shaped polyfunctionalized o-carborane synthons
No full text[EN] o-Carborane derivatives with precisely defined patterns of substitution have been prepared from 8,9,10,12-I-4-1,2-closo-C2B10H8 by replacing the iodine atoms, bonded to four adjacent boron vertices in the cluster, with allyl, and subsequently 3-hydroxypropyl groups. The resulting structures, comprising four pendant arms and two reactive vertices located on opposite sides of a central o-carborane core, can be envisaged as versatile precursors for dendritic growthThis work was supported by Generalitat de Catalunya 209/SGR/00279 and Spanish Ministerio de Ciencia e Innovacion by CTQ2010-16237.Puga, AV.; Teixidor, F.; Sillanpaa, R.; Kivekas, R.; Viñas, C. (2011). Synthesis of quadruped-shaped polyfunctionalized o-carborane synthons. Chemical Communications. 47(8):2252-2254. https://doi.org/10.1039/c0cc05151aS2252225447
The Crystal and Molecular structure of trans-Dichlorobis(1,3-Diaminopropan-2-ol)cobalt(III) Chloride
No full textA single-crystal X-ray structure determination of the title compound is reported. The compound crystallizes in the space group P1 with a 7.273(1), b 8.525(2), c 12.358(3) �, α 80.03(3),β 75.38(2), γ 65.06(2)� and Z 2. The final R value for 3318 reflections was 0.041. The structure consists of two independent trans- dichlorobis (l,3-diaminopropan-2-ol)cobalt(III) cations and chloride ions interconnected by a hydrogen bonding network. The axial Co-Cl bonds in the pseudo-octahedral coordination sphere are shorter than those in the coordination sphere of the copper(II) analogue. The compression is clearly related to the simultaneous flattening of the rings.</jats:p
Synthesis, reactivity and structural studies of selenide bridged carboranyl compounds
No full textReaction of the lithium salt Li[1-R-1,2-closo-C2B10H10] with selenium under mild conditions, followed by hydrolysis gave the diselenide compound (1-Se-2-R-1,2-closo-C2B10H10)2 in contrast to the well-reported mercapto compounds 1-SH-2-R-1,2-closo-C2B10H10 obtained using a similar synthetic procedure. Details for the preparation and X-ray structural characterisation of the new compounds (2-Me-1,2-closo-C2B10H10)2Se (1), (1-Se-2-R-1,2-closo-C2B10H10)2 (R = Me,2, Ph, 3) are specified. To further explore the mechanism of the dimerization reaction, the complex [Au(1-Se-2-Me-1,2-closo- C2B10H10)(PPh3)] 4 was synthesized, confirming the existence of the intermediate Li[1-Se-2-R-1,2-closo-C2B10H10] at the early stages of the reaction before selenium oxidation. Theoretical calculations and cyclic voltammetry (CV) studies were carried out to compare the bonding nature of the sulfur and the selenium analog compounds. It was determined that diselenides have a higher tendency to reduce with respect to the disulfides and all chalcogen atoms were found to be positively charged
Iodinated ortho-Carboranes as Versatile Building Blocks to Design Intermolecular Interactions in Crystal Lattices
No full text[EN] The crystal structures of numerous iodinated ortho-carboranes have been studied, which has revealed the diversity of intermolecular interactions that these substances can adopt in the solid state. The nature-mostly as it relates to hydrogen and/or halogen bonds-and relative strength of such interactions can be adjusted by selectively introducing substituents onto the cluster, thus enabling the rational design of crystal lattices. In this work we present the newly determined crystal structures of the following iodinated ortho-carboranes: 9-I-1,2-closo-C2B10H11, 4,5,7,8,9,10,11,12-I-8-1,2-closo-C2B10H4, 3,4,5,6,7,8,9,10,11,12-I-10,-1,2-closo-C2B10H2, 1-Me-8,9,10,12-I-4-1,2-closo-C2B10H7, 1,2-Me-2-8,9,10,12-I-4-1,2-closo-C2B10H6, and 1,2-Ph-2-8,9,10,12-I-4-1,2-c1oso-C2B10H6. Their 3D supramolecular organization has been thoroughly investigated and compared to similar previously published crystal structures. Such a systematic survey has allowed us to draw some general trends. C-c-H center dot center dot center dot I-B hydrogen bonds (C-c = cluster carbon atoms) appear to be significant in the growth of the crystal lattices of these compounds, given the acidity of hydrogen atoms bonded to C-c, and the polarization of B-I bonds. These hydrogen bonds can be disrupted by selectively blocking the positions next to C-c that is, B(3) and B(6), with bulky substituents that prevent iodine atoms from approaching as hydrogen acceptors. Halogen bonds of the type B-I center dot center dot center dot I-B are frequently observed in most cases, thus suggesting that these interactions could be attractive in boron clusters. In addition, different substituents can be grafted onto the ortho-carborane surface, thereby providing further possibilities for homomeric or heteromeric molecular assembly.This work was supported by CICYT (project MAT2006-05339), Generalitat de Catalunya (2005/SGR/00709).Puga, AV.; Teixidor, F.; Sillanpaa, R.; Kivekas, R.; Viñas, C. (2009). Iodinated ortho-Carboranes as Versatile Building Blocks to Design Intermolecular Interactions in Crystal Lattices. Chemistry - A European Journal. 15(38):9764-9772. https://doi.org/10.1002/chem.200900926S97649772153
Wideband planar slotted radiating ground plane antenna for portable devices
No full textA method for exciting currents in a radiating ground plane over a wide frequency bandwidth is presented. Using a complementary slot in the ground plane excited by a closely spaced monopole (0.008-0.05¿) with 50 Ω input impedance, a wide frequency bandwidth can be achieved to cover multiple radio interfaces. © 2011 Wiley Periodicals, Inc.This work was supported by Finnish Funding Agency for Technology and Innovation, Nokia Devices Oulu, Pulse Finland, and Spanish Ministerio de Ciencia y Tecnologia under project TEC2007-66698-C04-03/TCM. M. Sonkki thanks Universidad Politecnica de Valencia and COST IC0603 ASSIST for financially supporting his research exchange in Valencia.Tapani Sonkki, M.; Antonino Daviu, E.; Ferrando Bataller, M.; Salonen, ET. (2011). Wideband planar slotted radiating ground plane antenna for portable devices. Microwave and Optical Technology Letters. 53(12):2854-2858. https://doi.org/10.1002/mop.26408S285428585312Vainikainen, P., Ollikainen, J., Kivekas, O., & Kelander, K. (2002). Resonator-based analysis of the combination of mobile handset antenna and chassis. IEEE Transactions on Antennas and Propagation, 50(10), 1433-1444. doi:10.1109/tap.2002.802085E. Antonino M. Cabedo M. Ferrando J.I. Herranz Analysis of the coupled chassis-antenna modes in mobile handsets 2004Cabedo, A., Anguera, J., Picher, C., Ribo, M., & Puente, C. (2009). Multiband Handset Antenna Combining a PIFA, Slots, and Ground Plane Modes. IEEE Transactions on Antennas and Propagation, 57(9), 2526-2533. doi:10.1109/tap.2009.2027039A. Zhao J. Rahola Numerical and experimental study of a quarter-wavelength wideband slot antenna for mobile applications 2005A. Muscat J. A. Zammit Reconfigurable antenna structure for a wideband cognitive radio 2008 1 5L. Lui R. Langley Frequency-tunable mobile phone antennas with matching circuitry 2010 1 4Digital Video Broadcasting (DVB)Mushiake, Y. (1992). Self-complementary antennas. IEEE Antennas and Propagation Magazine, 34(6), 23-29. doi:10.1109/74.180638CST-Computer Simulation Technology http://www.cst.comHolopainen, J., Kivekas, O., Icheln, C., & Vainikainen, P. (2010). Internal Broadband Antennas for Digital Television Receiver in Mobile Terminals. IEEE Transactions on Antennas and Propagation, 58(10), 3363-3374. doi:10.1109/tap.2010.2055786Satimo http://www.satimo.co
Complexes of Cu(II) with mixed-donor phenanthroline-containing macrocycles: analysis of their structural, redox and spectral properties in the context of Type-1 blue copper proteins biomimetic models
No full textThe macrocycles L1–L3 having N2S2O-, N2S2-, and N2S3-donor sets, respectively, and incorporating the 1,10-phenanthroline unit interact in EtOH and MeCN solutions with CuII to give 1:1 [M(L)]2+ complex species. The compounds [Cu(L1)(ClO4)]ClO4 (1), [Cu(L2)(ClO4)]ClO4.12H2O (2) and [Cu(L3)](ClO4)2 (3) were isolated at the solid state and the first two also characterised by X- ray diffraction studies. The conformation adopted by L1 and L2 in the cation complexes reveals the aliphatic portion of the rings folded over the plane containing the heteroaromatic moiety with the ligands encapsulating the metal centre within their cavity by imposing, respectively, a square-based pyramidal and a square planar geometry. In both complexes, the metal ion completes its coordination sphere by interacting with a ClO4 ligand. The compound [Cu(L3)2](PF6)2 (4) containing a 1:2 cation complex was also isolated at the solid state: EPR spectroscopy measurements suggest the presence of a CuN4 chromophore in this complex. The EPR and electronic spectral features of 1–4 have been studied and their redox properties examined in comparison with those observed for Type-1 blue copper proteins.
The reactivity of L1–L3 has also been tested toward stoichiometric amounts of the CuI salt [CuCl(PPh3)3]
Stereospecific synthesis and crystal structure of the racemate of 1-thia-2-tellura-1(1-allyl-4-chloro)cyclopentane 2,2,2-trichloride
No full textReducing the interaction between user and mobile terminal antenna based on antenna shielding
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