China
Africa
Explore chapters and articles related to this topic
Light-Emitting Polymers
Published in Zhigang Rick Li, Organic Light-Emitting Materials and Devices, 2017
Shidi Xun, Dmitrii F. Perepichka, Igor F. Perepichka, Hong Meng, Fred Wudl
Makioka and coworkers [723] prepared phosphorus-containing polymers (2,7-(9-oxo-9-phosphafluorenylene)-alt-co-(1,4-arylene))s 644, which emit blue light in solution (413–433 nm) with rather high ΦPL (68%–81%), similar to PFs. In films, however, their emission is red shifted by 32–44 nm becoming green–blue, which is at a much higher wavelength than that for fluorene-alt-co-phenylene analogs [280,281,294,295] (Chart 2.149). The introduction of phosphorus-containing moieties into conjugated thiophene polymers has been investigated since the first polymeric system containing a phosphole unit (645) was reported [724]. The maximum emission peak of 645 is located at 470 nm with a quantum yield of 0.092 [724]. Baumgartner’s group has investigated the dithieno[3,2-b:2′,3′-d] phosphole systems and explored their optoelectronic properties [725–727]. Copolymer 646 containing dithieno[3,2-b:2′,3′-d]phosphole was synthesized and exhibits a very strong blue photoluminescence (λem = 424) due to the great distance between the emitting centers, reducing the potential for quenching processes that could occur at higher densities [725].
Perspective on the Advancements in Conjugated Polymer Synthesis, Design, and Functionality over the Past Ten Years
Published in John R. Reynolds, Barry C. Thompson, Terje A. Skotheim, Conjugated Polymers, 2019
Brian Schmatz, Robert M. Pankow, Barry C. Thompson, John R. Reynolds
Of the Group 13 elements, boron has garnered the most attention with the incorporation of boron-dipyrromethene (BODIPY, 80)-based repeat units into conjugated polymer architectures. These are highly emissive materials and have found extensive use in OLED applications.[46] However, other elements from this group have also been incorporated, such as gallium (79).[47] Moving away from carbon, Group 14 atoms have largely been well studied and extensively incorporated into conjugated polymers, specifically silicon and germanium, which are exemplified by polymers 81 and 82.[48] From Group 15, phosphorous is the most studied, particularly when arranged in various phosphole architectures with one illustrated as 83.[49] The tunability of the phosphorous, i.e. the modification of its oxidation state or the reactivity of its lone-pair electrons, allows for a variety of different materials and derivatives to be made. Quite often, the phosphorus is incorporated into a phosphole architecture with the phosphorus center either oxidized or coordinated to a metal. Oxidation of the phosphorus center will occur over time if the material is left under ambient conditions. Bismuth has also been incorporated into a heterocyclic format to yield bismole, 84. Akin to phospholes, synthesis of these materials remains challenging relative to other heterocycles due to the high reactivity of various synthetic intermediates.[50] Selenium and tellurium are some of the most well studied heteroatoms incorporated into conjugated polymers, such as 85 and 86, outside of the typically employed chalcogens oxygen and sulfur, and for a detailed discussion the reader is referred to Chapter 7.
31P NMR Data of Alkali Metal Phosphides
Published in John C. Tebby, CRC Handbook of Phosphorus-31 Nuclear Magnetic Resonance Data, 2017
is upfield when R1 and R2 are alkyl or hydrogen but downfield if either group is aryl, though the latter effect may be very small (<1 ppm). Phosphines with sterically demanding sub-stituents also show downfield shifts (2 to 20 ppm) on conversion to their phosphides. When the phosphorus atom forms part of an aromatic system, e.g., in a phosphole, then the downfield shift is very large (ca. 200 ppm).
Synthesis, characterization, and photophysical properties of a new 2,5-di(aryl)phosphole derivative and their trigonal copper–phosphole complexes
Published in Journal of Coordination Chemistry, 2021
Neskarlys Rios, Franmerly Fuentes, Deivi Oliveros, José R. Mora, Juan M. Garcia-Garfido, Yomaira Otero
Phosphole 1 showed a low quantum yield (Φf=0.04) due to chromophores that have σ3-P centers generally exhibit almost no fluorescence as a result of quenching by the lone pair of the phosphorus [32, 36, 66–69]. However, coordination of the phosphole ligands to metal center impacts the quantum yields [31, 32, 70]. Thus, we observed that 2a-b has values higher than those of the corresponding free phosphole (Φf=0.07 (2a); 0.11 (2b)) which is associated with the effect of the d10 metal ions on the fluorescence [26–29]. Values of fluorescence quantum yield of these complexes are the highest found in d10 trigonal Cu(I)-phosphine halide complexes [26, 29]. The fluorescence quantum yield of 2b is considerably higher than that of the free phosphole.
Molecular design of supramolecular polymers with chelated units and their application as functional materials
Published in Journal of Coordination Chemistry, 2018
Igor E. Uflyand, Gulzhian I. Dzhardimalieva
A chelating ligand consisting of a substituted phosphole ring surrounded by two thiophene rings with tpy end-groups was reacted with metal ions (Co2+, Cu2+, Fe2+, Ni2+, and Zn2+) to obtain MSPs [80]. A clear red shift of the UV/vis band by 60–100 nm indicates a decrease in the energy of the band gap due to substitution of thiophene-2,5-diyl for the phosphole-2,5-diyl central unit, which is due to the decreased aromaticity of the phosphole ring as compared to aromaticity of the thiophene ring. The metallosupramolecular polymerization yields oligomeric chains containing up to 10 monomeric units in dilute solutions. Interestingly, Fe2+- and Ni2+-based MSPs demonstrate very slow constitutional dynamics, while Cu2+- and Zn2+-based MSPs have rather rapid constitutional dynamics. MLCT is observed only for Fe2+-based MSPs, whereas luminescence is observed only for Zn2+-based MSPs, mainly with an excess of Zn2+ ions, indicating a positive effect of the end-capping of the MSP chains by these ions.
Effect of phosphorus on the electronic and optical properties of naphthoxaphospholes: theoretical investigation
Published in Molecular Physics, 2018
Jiwon Moon, Minbi Kim, Jeong Sik Lim, Joonghan Kim
As shown in Figure 1, the CPC and PCO bond angles of (b) and (d) as calculated by CAM-B3LYP/6-311+G(d) are in excellent agreement with the experimental values. The CPC bond angles of all R-NOPs are ∼88.0°, which is close to 90°. Geometry optimisation of an analogue of (c) where P atom was substituted with N atom ((c)-N) was performed to identify the effect of P atom (the relevant optimised molecular structure is shown in Figure S2(a) in the Supplemental Material (Online)). The CNC bond angle is 105.0°, which significantly differs from the CPC bond angle (88.1°). In addition, the NPA charge of P atom is +0.535, which drastically differs from that of N (–0.511), indicating a difference in electronic structure. Indeed, the natural electron configurations of P and N atom are P: 3s1.553p2.883d0.02 and N: 2s1.352p4.113d0.01, respectively. It is noted that the natural electron configuration of P atom is reduced from that of a bare P atom (3s23p3), resulting in a positive NPA charge for P atom (Table 1). However, in the case of N atom, the excess electron occupies 2s12p4 configuration to make the sp2 hybrid orbitals rather than that of a bare N atom (2s22p3). These results indicate that P atom in R-NOPs has considerable ionic character rather than covalent character (π bonding), leading to a CPC bond angle close to 90°. Similar results can be found in phosphole compounds, which can be regarded as a phosphorus atom bridged to a 1,3-diene unit [33].