- Tuning the Optoelectronic Properties of Stannoles by the Judicious Choice of the Organic Substituents
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Stannoles are organometallic rings in which the heteroatom is involved in a form of conjugation that is called σ?-π? conjugation. Only very little is known about how the substituents on the Sn atom or substituents on the stannole ring determine the optoelectronic properties of these heterocycles. In this work, this question has been studied experimentally and theoretically. Calculations of optimized equilibrium geometries, energy gaps between the highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs), and of the absorption spectra of a wide range of compounds were performed. The computational data showed that the substituents on the Sn atom influence the optoelectronic properties to a lower extent than the substituents in the 2 and 5 positions of the ring. These substituents in the 2 and 5 positions of the stannole ring can also have a strong influence on the overall planarity of the structure, in which mesomeric effects can play a substantial role only if the structure is planar. Thus, only structures with a planar backbone are of interest in the context of tuning the optoelectronic properties. These were selected for the experimental studies. On the basis of this information, a series of six novel stannoles was synthesized by the formation of a zirconium intermediate and subsequent transmetalation to obtain the tin compound. The calculated electronic HOMO-LUMO energy gaps varied between 2.94 and 2.68 eV. The measured absorption maxima were located between 415 and 448 nm compared to theoretically calculated values ranging from 447 nm (2.77 eV) to 482 nm (2.57 eV). In addition to these optical measurements, cyclic voltammetry data could be obtained, which show two reversible oxidation processes for three of the six stannoles. With this study, it could be demonstrated how the judicious choice of the substituents can lead to large and predictable bathochromic shifts in the absorption spectra.
- Ramirez Y Medina, Isabel-Maria,Rohdenburg, Markus,Mostaghimi, Farzin,Grabowsky, Simon,Swiderek, Petra,Beckmann, Jens,Hoffmann, Jonas,Dorcet, Vincent,Hissler, Muriel,Staubitz, Anne
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- Dopants for a perfluorinated graded index polymer optical fiber
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A perftuorinated graded index polymer optical fiber (PFGI-POF) has been developed and manufactured for data communication to provide a high bandwidth with easy termination and cabling. In the PFGI-POF technology, the graded refractive index profile using
- Naritomi, Masaki,Murofushi, Hidenobu,Nakashima, Naotoshi
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- Synthesis and characterization of perhalophenyltin derivatives. Study of their reactivity toward phosphine gold(I) chlorides
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The (perhalophenyl)tin derivatives [SnR4] (1-3) and [SnR 3Cl] (4-6) (R = C6F5, C6F 3Cl2, C6Cl5) were prepared from SnCl4 and LiR or [SnR4] in the appropriate molar ratio, while the dinuclear complexes [SnR3]2 (7-9) were obtained by treatment of [SnR3Cl] with potassium under toluene reflux. Complexes 2, 6·0.5toluene and 7 were structurally characterized, the latter displaying a Sn-Sn bond of 2.808(7) , which indicates a strong tin-tin bond with covalent character in solid state. The hexaaryldistannanes 7-9 undergo transmetallation reactions with gold(I) derivatives, such as [AuCl(PPh 3)] or [(AuCl)2(μ-dppm)], affording the neutral species [AuR(PPh3)] (10-12) or [(AuR)2(μ-dppm)] (13-15) or the ionic product [Au3Cl2(μ-dppm)2][Sn(C 6F5)3Cl2] (16). The crystal structures of 14·CH2Cl2, 15 and 16·2CH 2Cl2 were determined by X-ray diffraction, the latter showing a Au3 nearly equilateral triangular core in the cation with gold-gold contacts of 3.128(7) and 3.227(12) . The main difference between the molecular structures of 14·CH2Cl2 and 15 (both of them displaying intramolecular gold-gold contacts of 3.142(6) and 3.160(4) , respectively) is the presence of an intermolecular Au?Au interaction of 3.2126(8) in the case of the C6F3Cl2 complex that gives rise to a tetranuclear unit.
- Bojan, R. Vilma,López-De-Luzuriaga, José M.,Monge, Miguel,Olmos, M. Elena
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p. 2385 - 2393
(2010/11/03)
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- Silver compounds in synthetic chemistry. 1. A facile preparative route for pentafluorophenylsilver, AgC6F5 and its use as an oxidative pentafluorophenyl group transfer reagent in reactions with group 12 to 16 elements
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AgC6F5 is directly and quantitatively formed from room temperature reactions of AgF and Me3SiC6F5 in N-donor solvents, particularly EtCN. Solutions of AgC6F5 prepared by this method exhibit excellent oxidative properties in reactions with a variety of groups 12 to 16 elements giving the corresponding pentafluorophenyl element compounds in moderate to excellent yields. AgC6F5·EtCN crystallises with monoclinic symmetry (C2/c, Z = 8, a = 2301.4(5)pm, b = 1078.8(4)pm, c = 948.0(2)pm, β = 113.19(1)°) and exhibits chains of silver atoms with bridging C6F5 groups.
- Tyrra, Wieland,Wickleder, Mathias S.
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p. 1841 - 1847
(2008/10/08)
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- Organothallium compounds. VI. Reactions of bromobis(pentafluorophenyl)thallium(III) with main group elements
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Bromobis(pentafluorophenyl)thallium(IlI) reacts with many main group elements on heating in the absence of a solvent to give pentafluorophenyl derivatsves of these elements. The compounds C6F5M (M = Cl, Br, or I), (C6F5)2M (M = Zn, Cd, Hg, S, Se or Te), (C6F5)3M (M = In, P, As, or Sb), and (C6F5)M (M = Ge or Sn) have been prepared by this method. Substantial decomposition of (C6F5)2TlBr occurs on reaction with aluminium, gallium, lead and bismuth, but pcntafluorophenyl derivatives of these elements are not obtained.
- Deacon,Parrott
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p. 287 - 295
(2008/10/08)
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