Phosphole Sulfide Research Articles

Annulation of phosphole sulfides via [3 + 2] cycloaddition with nitrones

We developed a facile pathway for the construction of the phospholene fused isoxazolidine skeleton through the [3 + 2] cycloaddition reaction of phosphole sulfides.

Aggregation-induced emission fluorophore doped phosphate glass: Toward light-emitting electrochemical cells

Light-emitting electrochemical cells (LECs) are an easy-to-fabricate electroluminescent device, which in its simplest manifestation comprises an electroluminescence organic fluorophore and electrolytes as the active layer sandwiched between two electrodes. The LEC exhibits poor operational stability, and the poor thermal stability of the electrolyte is a major cause of the instability. Because most of the electrolytes utilized in LEC are organic electrolytes (polymer and ionic liquids), the thermal stability is difficult to improve on a large scale. Therefore, in this work, we are devoted to preliminarily exploring the possibility of using an inorganic glass electrolyte for LEC application. Following this objective, organic fluorophore (π-extended phosphole sulfide 1) doped inorganic phosphate amorphous matrix was successfully synthesized using spark plasma sintering technology. The optical properties, microstructure, and electrochemical properties of the hybrid glass were investigated, respectively. The ionic conductivity of the glass host can reach 10−7 S/cm at room temperature, and the glass matrix contain aggregates of 1 of around 100 nm. Strong photoluminescence at 600 nm, characteristic of the organic fluorophore, was observed in the hybrid glass. The cyclic voltammetry performed on the hybrid glass shows a redox couple contribution of the organic fluorophore. The result suggests 1 can complete the exchange of electric charges in the inorganic glass electrolyte, which is one of the fingerprints of the transient phenomena of a LEC.

Synthesis of π‐conjugated polymer containing both thiophene and phosphole sulfide in the main chain by simultaneous post‐element transformation of organotitanium polymer

ABSTRACTThe synthesis and unique optoelectronic features of a π‐conjugated polymer containing both thiophene and 1‐phenylphosphole sulfide units (multiple heteroles) in the main chain by the post‐element transformation of a regioregular organometallic polymer possessing titanacyclopentadiene‐2,5‐diyl unit are described. The π‐conjugated polymer containing multiple heteroles was obtained in 73% yield by the simultaneous reaction of the organotitanium polymer with sulfur monochloride and dichlorophenylphosphine (0.6 equiv each), whose number‐average molecular weight (Mn) and the molecular‐weight distribution (Mw/Mn) were estimated to be 11,000 and 3.4, respectively, by the size exclusion chromatography (SEC). The π‐conjugated polymer thus obtained was found to have the high HOMO and the low LUMO energy levels due to the electron‐rich thiophene and electron‐deficient phosphole sulfide units, respectively, as supported by its cyclic voltammetry (CV) analysis. Compared to a mixture of a polymer containing sole thiophene‐unit and that containing sole phosphole sulfide units, the π‐conjugated polymer‐containing multiple heteroles proved to exhibit interesting optical properties. For example, a specific emission peak was observed at 608 nm in the photoluminescence spectrum, which was not observed in the case of the thiophene‐containing polymer, the phosphole‐containing polymer, and their mixture. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2519–2525

Revisiting the Chemistry of Phosphinidene Sulfides

The reaction of triethylamine with the [4 + 2] cycloadducts of phosphole sulfides and 3-bromo-N-phenylmaleimide provides a convenient access to phosphinidene sulfides [RP═S]. These transient species are trapped by 2,3-dimethyl-1,3-butadiene to give the previously unknown trivalent [4 + 2] cycloadducts. One of these (R = Ph) has been characterized as its P-W(CO)5 complex by X-ray crystal structure analysis. With cyclopentadiene, the subsequent insertion of a second molecule of [RP═S] leads to a new type of bicyclic product containing a thiadiphospholane ring.

Synthesis and (Spectro)electrochemical Behavior of 2,5-Diferrocenyl-1-phenyl-1H-phosphole

2,5-Diferrocenyl-1-phenyl-1H-phosphole (3) has successfully been prepared by a cyclization reaction of phenylphosphine with 1,4-diferrocenyl butadiyne. Subsequent reaction with elemental sulfur and selenium, respectively, leads to the formation of the appropriate phosphole sulfide (4) or selenide (5). Molecules 4 and 5 have structurally been characterized by single-crystal X-ray diffraction. Despite the tetrahedral environment at the phosphorus atom, the cC4P ring itself is planar and coplanar with the cyclopentadienyl rings of the ferrocenyl termini. Electrochemical measurements revealed that the two ferrocenyl groups could be oxidized at discrete potentials, with separation of the individual redox waves of 280 (3), 240 (4), and 235 mV (5), respectively. These values agree with other examples of heterocyclic-bridged diferrocenyl compounds such as diferrocenylthiophene (260 mV) and diferrocenylfuran (290 mV). Compounds [3]+–[5]+ exhibit IVCT absorptions of weak to moderate strength, which conforms well to the predictions of the Hush two-state model for weakly coupled mixed-valence systems. These conclusions are supported by DFT and TD-DFT results, which satisfactorily model the observed structural and spectroscopic parameters. The computational work assists in assigning the various low-energy (LF, IVCT) electronic transitions and also highlights the key role of the unsaturated cis-diene-like C4H2 building block of the heterocycle in promoting the Fc → Fc+ electron-transfer transition.

Luminescent P-Benzyl Dithienophospholes – A Joint Experimental and Theoretical Investigation

A series of P-benzyl functionalised dithieno[3,2-b:2′,3′-b]phospholes with different substitution pattern at the phosphorus as well as the conjugated scaffold was synthesised and characterised via optical spectroscopy. Single crystal X-ray crystallography was performed on one species. The experimentally observed data were solidified with density functional theory calculations. In contrast to related benzylated P-phenyl phospholium species, the new systems show pronounced photoluminescence in solution, with the exception of the phosphole sulfide species. The observed photophysics could be explained with dominating π→π* transitions, despite the presence of the benzyl group that had been found to quench the fluorescence in the predecessor benzyl system with P-phenyl substituent.

Bis(azidophenyl)phosphole Building Block for Extended π‐Conjugated Systems

AbstractNovel bis(azidophenyl)phosphole sulfide building block 8 has been developed to give access to a plethora of phosphole‐containing π‐conjugated systems in a simple synthetic step. This was explored for the reaction of the two azido moieties with phenyl‐, pyridyl‐ and thienylacetylenes, to give bis(aryltriazolyl)‐extended π‐systems, having either the phosphole sulfide (9) or the phosphole (10) group as central ring. These conjugated frameworks exhibit intriguing photophysical and electrochemical properties that vary with the nature of the aromatic end‐group. The λ3‐phospholes 10 display blue fluorescence (λem = 460–469 nm) with high quantum yield (ΦF = 0.134–0.309). The radical anion of pyridyl‐substituted phosphole sulfide 9b was observed with UV/Vis spectroscopy. TDDFT calculations on the extended π‐systems showed some variation in the shape of the HOMOs, which was found to have an effect on the extent of charge transfer, depending on the aromatic end‐group. Some fine‐tuning of the emission maxima was observed, albeit subtle, showing a decrease in conjugation in the order thienyl < phenyl < pyridyl. These results show that variations in the distal ends of such π‐systems have a subtle but significant effect on photophysical properties.

ChemInform Abstract: Reaction of Phosphole Sulfides with Diazoalkanes as a New Route to Phosphinines.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

An Unexpected Sequence: From Phosphole Sulfide to Phosphole- and Thiophene-Annulated 1,2-Dithiole-3-thiones

The deprotonation of 1-phenyl-3,4-dimethylphosphole sulfide by a bulky base, followed by the reaction of S2Cl2, unexpectedly yields a phosphole-annulated 1,2-dithiole-3-thione. The complexation of this product by [W(CO)5] takes place at C═S as expected on the basis of theoretical calculations. Another product results from the unprecedented replacement of the P(S)Ph unit by sulfur, giving the corresponding thiophene derivative.

Benzo[b]phosphole sulfides. Highly electron-transporting and thermally stable molecular materials for organic semiconductor devices

A benzo[b]phosphole sulfide derivative DBPSB was found to function as a new class of n-type amorphous organic material, which features high electron drift mobility and high thermal stability, and the utility of this compound was demonstrated in an organic light-emitting diode.

Synthesis and structure of 1‐phospholyl‐ and di(1‐phospholyl)acetylenes and the corresponding sulfides

AbstractThe acetylenes possessing one and two 1‐phospholyl groups were synthesized by reaction of the alkynyl Grignard reagents with the 1‐chlorophosphole and converted to the corresponding phosphole sulfides. Reaction of the 1‐phenylethynylphosphole sulfide with CpCo(CO)2 resulted in η4‐complexation on the phosphole moiety. The structures of the di(1‐phospholyl)acetylene disulfide and the [η4‐(1‐phenylethynylphosphole sulfide)]cobalt(I) complex were characterized by X‐ray crystallography. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:344–349, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20230

Reaction of phosphole sulfides with diazoalkanes as a new route to phosphinines

The reaction of ethyl diazoacetate with 1-(methylthio)-3,4-dimethylphosphole 1-sulfide (6) in refluxing xylene leads to a corresponding diene-carbene [2+1] cycloadduct (7). The stereochemistry of 7 was established by X-ray crystal structure analysis. Compound 7 is converted into 2-(ethoxycarbonyl)-4,5-dimethylphosphinine upon reaction with triphenyl phosphite at 160°C

Electron Impact Stabilities of Phospholes and Related Compounds and their Relative “Aromaticity”

Abstract Electron impact mass spectral fragmentation of a number of phosphole, phosphole oxide, phosphole selenide, and phosphole sulfide derivatives has been used as a probe for part of an on-going examination of the inherent stability, or “aromaticity” of these heterocycles. Ion current measurements and large fragment fragmentation patterns obtained from these compounds as well as from carbocyclic, and other heterocyclic analogs will be presented as one approach to determining the relative stabilities of these systems. The stability patterns obtained appear to be consistent with the relative stabilities established by other methods.

An unusual synthesis of 2,3‐dihydrophosphindole 1‐oxides

AbstractA very simple route to dimeric phosphole oxides is reported as is the pyrolytic decomposition of these phosphorus‐bridged dimers. Like similar dimeric phosphole sulfides, these phosphole oxide dimers readily eliminate the bridging phosphorus grouping upon strong heating but, unlike the analogous sulfides, hydrogen transfer to give a 2,3‐dihydrophosphindole 1‐oxide rather than hydrogen elimination to give the fully unsaturated phosphindole oxide occurs. This hydrogen transfer is shown to be non‐stereospecific and some mechanistic implications of this are briefly discussed.

Reduction—complexation des sulfures de phosphines par les fer-carbonyles

1-Phenyl-3,4-dimethylphosphole (L) yields the classic σ complex LFe(CO) 4 with Fe 2(CO) 9 and the unsual σ,π complex LFe 2(CO) 7 with Fe 3(CO) 12, whereas 1-t-butyl-3,4-dimethylphosphole (L′) with Fe 3(CO) 12 yields L′Fe 2(CO) 6 which belongs to a type already described in the literature. With Fe 2(CO) 9 at 85°C, the phosphole sulfide LS yields the two σ and σ,π complexes directly by reduction—complexation. This Fe 2(CO) 9 reduction—complexation process works only with phosphole and phospholene sulfides. However, with Fe(CO) 5 in great excess at 150°C, a general phosphine sulfide reduction—complexation procedure takes place. A study of the displacement of 1-phenyl-3,4-dimethyl-3-phospholene (L″) from its σ complex L″Fe(CO) 4 by trimethylphosphite has shown that L″ has a greater complexing ability toward iron than the phosphite, contrary to what could be expected from the work of Tolman on nickel complexes.

A new route to the phosphindole system

AbstractA new and possibly general route to the hitherto relatively inaccessible simple substituted phosphindoles, utilizing the extreme readiness of simple phosphole sulfides to undergo Diels‐Alder dimerization, is described. The synthesis reported here is that of 3,6‐dimethyl‐l‐phenylphosphin‐dole sulfide which is prepared in good yield in two simple steps from the readily available 3‐methyl‐l‐phenylphosphole.

Derives α-carbonyles et “aromaticite” des phospholes trivalents

A two-step synthesis of 2-acetyl and 2-carbethoxy-phospholes involves the metalation of monomeric 3,4-dimethyl phosphole sulfides by t-butyl-lithium followed by reaction with ethyl acetate and ethyl carbonate. The phosphole sulfides thus obtained are reduced by PBu 3 or P(CH 2CH 2CN) 3 to the phospholes 20– 24. In the 2-acetyl-phosphole series, variable electron transfer from the dienic system and from the phosphorus atom to the carbonyl group is monitored by 1H and 31P NMR. The main decomposition path of 2-carboxy phosphole 25 in the mass spectrometer involves a PC intracyclic bond cleavage with loss of CO, in sharp contrast with pyrrole and thiophene derivatives 26 and 27. These facts militate against strong 2 p π–3 p π electronic delocalisation in the phosphole nucleus.

Cycloadditions of 3,4-dimethyl-1-thio-1-phenyl phosphole

Phosphole sulfide 1 undergoes cycloaddition to give a new 15-phosphasteroid. The 13C-NMR and 2J PC-coupling constants of several compounds prepared similarly are discussed, permitting structure assignment to one of the 7-phosphabicyclo[2.2.1]heptane adduct 5. Thiophosgene reacts with the PS moiety of 1, giving 12 after hydrolysis, through a PS to PO transformation coupled in case of 1 with a proton migration.

8-Phosphabicyclo[3.2.1]octanes—III 4: The reaction between oxyallyl cations and phosphole derivatives

The reaction of oxyallyl cations with phosphole sulfide as well as phosphole oxides was investigated and was found to give the expected 8-phosphabicyclo[3.2.1]octanic system ( 2, 4 and 7) apart from other unexpected products ( 3 and 5). In the case of the phosphole sulfide ( 1), the oxyallyl cation is believed to react preferentially with the P=S group, rather than the dienic moiety, leading to a P=S to P=O transformation or to a very particular reaction resulting in 5. This occurs through an intermediate ( j) in which a C=S group reacts in a [2 + 4] cycloaddition with the phosphole as a diene. The structure and stereochemistry of the various products were established by the aid of their spectral data in conjunction with spectral data of some related compounds. A formal PhPO elimination is believed to occur through an intermediate phosphinate resulting from Bayer-Villiger like oxidation, which then loses the [PhPO 2] group. Phosphole sulfide ( 1), previously found to react as a dienophile, was shown to enter a [2 + 4] cycloaddition as a diene with powerful dienophiles like 4-methyl-1,2,4-triazoline-3,5-dione ( 10).

Preparation et proprietes de quelques sulfures de phospholes fonctionnels

tBuLi with 1-phenyl 3,4-dimethyl phosphole sulfide 1 in THF, gives a mesomeric anion 4. With aldehydes and ketones, this anion leads to methyl-substituted phospholes ( 6 and 9), 2-substituted phospholes ( 8) or 2-substituted 3-methylene phosphol 4-enes ( 5 and 7). With CO 2 and CH 3COOEt a 2-phosphole carboxylic acid 11 and a 2-acetyl phosphole 10 are obtained, respectively. The spectra of the 2-substituted phospholes are studied in some detail. Some of their chemical properties (dimerization, dissociation and tert-butylation) are also described.