Influence of pH and type of counterion on the formation of bismuth(III) complexes with tropolonato and 5-methyltropolonato ligands: Synthesis, structure, spectroscopic characterization and calculation studies
摘要:
Reactions of tropolone (Htrop) and 5-methyltropolone (5-meHtrop) with bismuth(III) triflate, perchlorate and nitrate in methanol solution at pH below 0 lead to the formation of different complexes with monomeric (Bi(5-metrop)(2)(NO3) (7)), dimeric ([Bi(trop)(2)(CF3SO3)](2) (1)) or polymeric structures ([Bi-2(trop)(4)(ClO4)(2)](n) (2), [Bi-2(trop)(4)(NO3)(2)](n) (3), [Bi-2(5-metrop)(4)(CF3SO3)(2)](n) (5) and {[Bi-2(5-metrop)(4)(ClO4) MeOH]ClO4}(n) (6)). On the other hand, if the syntheses are performed at higher pH the simple homoleptic Bi(trop) 3 (4) and Bi(5-metrop) 3 (8) compounds are obtained independently of the bismuth(III) salt used. The crystal structures of studied compounds have been determined by single-crystal X-ray diffraction. The molecular structure of 7 has been compared with its geometry received from DFT calculations giving a good correlation. The structures of 4 and 8 have been also simulated by means of the DFT method because it was not possible to obtain sufficiently large single crystals. The total coordination number of the bismuth(III) ion is six in 7, seven in 1, eight in 2, 5 and 6 and nine in 3. The optimized geometry for 4 and 8 shows a distorted triangle antiprism of oxygen atoms around metal center with three shorter and three longer Bi-O bond lengths. The compounds were characterized by FT-IR, NMR and UV-Vis techniques. IR and UV-Vis spectra of 4, 7 and 8 were also simulated by DFT methods. TD-DFT predictions demonstrate the frontier HOMOs and LUMOs cover the ligands giving LLCT character of the lowest-lying electronic transitions. NBOs analysis for these three complexes shows low p character of 5.6% (4 and 8) or 7.3% (7) for the 6s(2) lone electron pair on the bismuth(III) ion. (C) 2015 Elsevier B.V. All rights reserved.
Ring-Closing Synthesis of Dibenzothiophene Sulfonium Salts and Their Use as Leaving Groups for Aromatic <sup>18</sup>F-Fluorination
作者:Thibault Gendron、Kerstin Sander、Klaudia Cybulska、Laure Benhamou、Pak Kwan Brian Sin、Aqsa Khan、Michael Wood、Michael J. Porter、Erik Årstad
DOI:10.1021/jacs.8b06730
日期:2018.9.5
Herein, we report a novel intramolecular ring-closing reaction of biaryl thioethers that give access to highly functionalized dibenzothiophene sulfonium salts under mild conditions. The resulting precursors react regioselectively with [18F]fluoride to give [18F]fluoroarenes in predictable radiochemical yields. The strategy expands the available radiochemical space and provides superior labeling efficiency
在此,我们报道了联芳基硫醚的一种新型分子内闭环反应,该反应可以在温和条件下获得高度官能化的二苯并噻吩锍盐。所得前体与[ 18 F]氟化物发生区域选择性反应,以可预测的放射化学产率生成[ 18 F]氟芳烃。该策略扩大了可用的放射化学空间,并为临床相关 PET 示踪剂提供了卓越的标记效率。
Distinction between coordination and phosphine ligand oxidation: interactions of di- and triphosphines with Pn<sup>3+</sup> (Pn = P, As, Sb, Bi)
作者:Saurabh S. Chitnis、Kevin A. Vos、Neil Burford、Robert McDonald、Michael J. Ferguson
DOI:10.1039/c5cc08086j
日期:——
Hard and soft acceptors react differently towards phosphine donors, defining a range of phosphine coordination chemistry outcomes for p-block elements.
硬和软受体对膦供体的反应不同,为p区元素的膦配位化学结果定义了一系列不同的可能性。
Pd-Catalyzed Aerobic Oxidative Biaryl Coupling: Non-Redox Cocatalysis by Cu(OTf)<sub>2</sub> and Discovery of Fe(OTf)<sub>3</sub> as a Highly Effective Cocatalyst
作者:Dian Wang、Shannon S. Stahl
DOI:10.1021/jacs.7b01970
日期:2017.4.26
Pd-catalyzed oxidationreactions, and they are typically used as oxidants or redox-active cocatalysts. Here, we probe the origin of a dramatic acceleration effect of Cu(OTf)2 in the C-H/C-H aerobic oxidative coupling of o-xylene. NMR spectroscopic analysis of the PdII catalyst in the presence of Cu(OTf)2, together with other experimental and DFT computational studies of the catalytic reaction, show that
Tropolone as anionic and neutral ligand in lead(II) and bismuth(III) complexes: Synthesis, structure, characterization and computational studies
作者:Krzysztof Lyczko
DOI:10.1016/j.molstruc.2016.08.005
日期:2017.1
new metal complexes, [Bi(trop)2(Htrop)(CF3SO3)] (1) and [Pb(trop)2(Htrop)] (2), have been synthesized by reaction of the respective metal triflates with an excess of tropolone (Htrop) in the concentrated methanol or dimethylsulfoxide solution. In addition, it was found that complex1 crystallizes through the formation of unstable intermediate methanol solvated tris(tropolonato)bismuth(III) compound
with GaCl3 led to decomposition into bismuth black, TerNH2·GaCl3, and [TerNH3][GaCl4], the reactions of 1 with 1 and 2 equiv of Ag[OTf] resulted in methyl/triflate exchange reactions affording TerN(SiMe2OTf)Bi(Me)Cl (2) and TerN(SiMe2OTf)Bi(Me)OTf (3). To circumvent the methyl/triflate exchange, the diiodide compound TerN(SiMe3)BiI2 (5) and the azide-substituted derivatives TerN(SiMe3)Bi(Cl)N3 (6) and