3-Bromo- and 6-chloroquinolines or 2-bromo-1-methylbenzimidazole react with red phosphorus in the KOH/DMSO (Н2О) system on heating (100–120°C, 3 h) to form in high yield the products of selective reduction (with retention of the aromatic heterocycle): quinoline or 1-methylbenzimidazole, respectively.

Organophosphorus compounds (OPCs) are used in many areas of human activity. Unique physicochemical properties and high biological activity not only determine the applied value of OPCs but also give them the properties of xenobiotics that are harmful to human health, which largely depend on the state of the endogenous microbiota. The purpose of this work is to assess the effect of pyridyl- and aryl-containing phosphines, their oxides, and sulfides on the growth of Bifidobacterium bifidum and Escherichia coli and to identify possible patterns of biotransformation of OPCs using 31P NMR spectroscopy. Bacteria were cultivated in thioglycollate medium containing the tested phosphorus compounds. At the stationary growth phase was determined the cell concentration and were recorded spectra 31P NMR. It was shown that the most reliable (p<0,05) and opposite effect on the growth dynamics of both species of bacteria was exhibited by phosphine sulfides 1 and 3: PS1 (pyridyl) reduced the population reproduction rate by 35–40%, and PS3 (aryl) increased it by 45–60%. At the same time, OPCs themselves were most likely not metabolized. Phosphine oxides reduced the average titer of bacteria compared to the control, and PO3 caused complete cell elimination after 24 hours cultivation. In the medium with PO2 was identified PS2 appeared, which may be caused by the biologically mediated process of oxide-to-sulfide conversion. All phosphines are chemically labile and they were oxidized abiotically to oxides and sulfides. Formed sulfides could be the reason for a significant increase (to 35%) in the growth rate bacteria population both species. Five new unidentified organophosphorus compounds (UPC) were recorded on medias with B. bifidum, some of which may belong to the products of biotransformation of the original OPCs. Some organic phosphates, homologous to the phosphine oxides tested, have a δp value neighboring to the taken NMR spectra. This may indicate the way of their biological transformation: oxidation of the CP bond in the phosphine oxides to an ester bond of organic phosphates. This ability of bifidobacteria to metabolize OPCs will make it possible to develop a therapeutic strategy based on the use of B. bifidum as a microorganism that degrades phosphorus-containing xenobiotics.

Triton-X-100, a polyethylene glycol 4-(tert-octyl)phenyl ether, has been found to be an active micellar organic catalyst for the one-pot selective synthesis of arylmethyl-H-phosphinic acids in up to 65% yields by the direct phosphinylation of arylmethyl halides with red phosphorus in the KOH/H2O/toluene multiphase superbase system. The catalyst demonstrates a good recyclability. As a result, an expeditious method for the chemoselective synthesis of arylmethyl-H-phosphinic acids-versatile sought-after organophosphorus compounds-has been developed. The synthesis is implemented via direct alkylation/oxidation of red phosphorus with arylmethyl halides, promoted by superbase hydroxide anions using Triton-X-100 (a commercial off-the-shelf organic recyclable micellar catalyst). The reaction comprises the hydroxide anions-assisted disassembly of P-red 3D polymer molecules triggered by the separation from the potassium cation in ordinary crown-like micelles to produce polyphosphide anions in aqueous phase. Further, polyphosphide anions are alkylated with arylmethyl halides in organic phase in the presence of the catalytic Triton-X-100 reverse micelles and alkylated polyphosphide species undergo the double hydroxylation. The advantages of the strategy developed include chemoselectivity, benign and accessible starting reagents, catalyst recyclability, and facile one-pot implementation.

Tertiary phosphine oxides, phosphine sulfides, and phosphine selenides containing pyridine, imidazole, and pyrazole groups have been synthesized via the reaction of elemental phosphorus or secondary phosphine oxides with functional pyridines, imidazoles, and pyrazoles. Alkyl tris(2-pyridylethyl)phosphonium iodide and bromide are also obtained by quaternization of the corresponding phosphine. Antimicrobial activity of the synthesized compounds, including nitrogen-containing heterocycles, phosphorus, selenium, and sulfur, with respect to Enterococcus durans, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa microorganisms is evaluated. It is found that phosphine chalcogenides bearing imidazole (14, 19), pyrazole (13), and pyridine fragments (5, 9) and phosphonium salts (11, 12) can be considered as new promising antibacterial agents. For some synthesized compounds, LC50 is determined. Phosphine oxide with methylpyrazole fragments (13) and phosphonium salts (11, 12) show strong profile of antimicrobial activity, and cytotoxic effect of phosphonium bromide having a long chain radical (12) is by order of magnitude higher than that of cisplatin. We believe that the results obtained may contribute to the development of highly effective agents for the treatment and prevention of bacterial infections and cancers.

Tris(hetaryl)substituted phosphines and their chalcogenides are promising polydentate ligands for the design of metal complexes. An experimental and theoretical conformational analysis of tris[2-(4-pyridyl)ethyl]phosphine, tris[2-(2-pyridyl)ethyl]phosphine, and their chalcogenides was carried out by the methods of dipole moments, IR spectroscopy and DFT B3PW91/6-311++G(df,p) calculations. In solution, these compounds exist as an equilibrium of mainly non-eclipsed (synclinal or antiperiplanar) forms with a predominance of a symmetrical conformer having a gauche-orientation of the Csp3–Csp3 bonds of pyridylethyl substituents relative to the P=X bond (X = lone pair, O, S, Se) and a gauche-orientation of the pyridyl rings relative to the zigzag ethylene bridges. Regardless of the presence and nature of the chalcogen atom (oxygen, sulfur, or selenium) in the studied molecules with many axes of internal rotation, steric factors—the different position of the nitrogen atoms in the pyridyl rings and the configuration of ethylene bridges—determine the realization and spatial structure of preferred conformers.

Tertiary phosphine oxides have been synthesized by the reaction of secondary phosphine oxides with diverse hetarylmethylchlorides (pyridines, imidazoles, pyrazole) in the superbasic systems CsF/NaOH/DMF/4 angstrom MS or NaOH/DMSO/4 angstrom MS at 23-25 degrees C. It is found that a tertiary phosphine oxide bearing the imidazole fragment possess the pronounced antimicrobial activity.

Polyfluoroalkyl dichlorophosphites reacted with propargyl alcohol in Et3N/hexane to give di(2-propynyl) polyfluoroalkyl phosphites, which are transformed into polyfluoroalkyl 2-propynyl allenylphosphonates and isomeric (1-propynyl)phosphonates upon storage.

Alkylphosphinic acids, including long-chain ones, were synthesized in up to 76% yields from red phosphorus and n-AlkBr (Alk = C4–C14) under micellar catalysis conditions. The reaction proceeds efficiently and chemoselectively upon heating (85–90°C, 6 h) in a KOH/H2O/toluene/cetyltrimethylammonium bromide system.

Long-chain n-Alkylphosphonic acids, AlkP(O)(OH)(2), are synthesized in up to 91 % yield (mostly 40-60 %) by straightforward phosphonylation of alkyl bromides (AlkBr, Alk=C-4-C-18) with red phosphorus (P-n) in the multiphase KOH/H2O/toluene system in the presence of 2-10 mol % of cetyltrimethylammonium bromide (CTAB), acting as a micellar/phase transfer catalyst and as a generator/transporter of superbasic hydroxide anions, the intermediate potassium phosphinates being in situ oxidized/neutralized by nitric acid. The key steps of the phosphonylation mechanism are the P-P bond cleavage of P-n polymeric molecules by superbasic -OH anions, dissolved in the CTAB micelles, and phase transfer of polyphosphide anions to the organic phase and their alkylation with AlkBr.

The polarity and structure of tri(1- or 2-naphthyl)phosphines and their chalcogenides were determined by the methods of dipole moments, IR spectroscopy, and DFT quantum-chemical calculations at the B3PW91/6-311++G(df,p) level of theory. In solution, tri(1-naphthyl)phosphine prefers a single conformer with a gauche,gauche,gauche orientation of the substituents at the phosphorus. Tri(2-naphthyl)phosphine, as well as both phosphine chalcogenides exist as equilibrium mixtures of several forms with a propeller arrangement of the substituents and a cis or gauche orientation of the Csp2‒Csp2 and P=X (X = LEP, O, S, Se) bonds.

The first example of a triply bridging (μ 3 -P) phosphine ligand has been discovered in the crown-shaped [Cu 3 (μ 2 -Hal) 3 L] (Hal=Cl, Br, or I) complexes supported by tris[2-(2-pyridyl)ethyl]phosphine (L). Theoretical analysis completely confirms the observed μ 3 -P-bridging pattern, revealing the interaction of the same lone pair of phosphorus with three valence 4s-orbitals of Cu atoms. The presented complexes exhibit outstanding blue phosphorescence ( λ em =442–465 nm) with the quantum efficiency reaching 100 %. The complex [Cu 3 (μ 2 -I) 3 L] also exhibits remarkable thermo- and mechanochromic luminescence resulting in a sharp change in the emission colour upon external stimuli. These findings essentially contribute to coordination chemistry of the pnictine ligands.

The reaction of [Mo3S4(Tu)8(H2O)]Cl4·4H2O (Tu is thiourea) with (PhCH2CH2)2-PCH2CH2SeC5H11) (PSe) followed by purification on a chromatographic column packed with silica gel using a saturated solution of KPF6 in acetone as an eluent results in the formation of [Mo3S4Cl3(PSe)3]PF6 (I) in a yield of 44%. Compound I is characterized by X-ray diffraction analysis, 1H, 31P{1H}, and 77Se NMR spectroscopy, IR spectroscopy, UV-Vis spectroscopy, cyclic voltammetry, and electrospray ionization mass spectrometry. Several species differed in the coordination mode of three PSe ligands, which can bind to molybdenum via one (phosphorus) or two (phosphorus and selenium) donor atoms, are formed in a solution of compound I at room temperature. This behavior is not observed for the compounds similar in structure with PS ligands of an analogous type. Complex I demonstrates a higher catalytic activity than its analogue with the PS ligand in the reduction of nitrobenzene to aniline under the action of diphenylsilane.

Long-chain n-alkyl-H-phosphinic acids (Alk = C4-C18) are chemoselectively synthesized in yields up to 90% via the direct one-pot alkylation/oxidation of red phosphorus (Pn) in the multi-phase alkyl bromide/KOH/H2O/toluene system with alkyl-PEG recyclable micellar catalysts, which demonstrate good recyclability.

Conformational analysis of tris(4-methylphenyl)phosphine and its oxide, sulfide, and selenide has been performed by the dipole moment method and DFT quantum chemical calculations at the B3PW91/ 6-311++G( df , p ) level of theory. The title compounds have been found to exist in solution as a single symmetrical conformer with gauche , gauche , gauche orientation of the substituents on the phosphorus atom with respect to the P=X bond (X = LEP, O, S, Se).

Reactions of [W3S4(tu)(8)(H2O)]Cl-4 center dot 2H(2)O (tu = thiourea) with (PhCH2CH2)(2)PCH2CH2SR (R = Ph (PS1) or n-pentyl (PS2), followed by chromatography on silica gel with a solution of KPF 6 in acetone as eluent, result in [W3S4Cl3(PS1)(3)]PF6([1]PF6) and [W3S4Cl3(PS2)(3)]PF6([2]PF6) in moderate yields. Crystal structures of [1]PF6 and [2]PF6 were determined by X-ray single crystal analysis. All three phosphine-thioether molecules are bidentately coordinated to tungsten atoms in such a way that the phosphorus atoms are in the trans position to the capping mu(3)-S atom. The compounds were characterized by H-1, P-31{H-1} NMR, and UV-vis spectroscopies and electrospray-ionization mass spectrometry. Unlike similar molybdenum complexes, interaction of [1]PF6 or [2] PF6 with Bu4NCl does not lead to the formation of neutral complexes [W3S4Cl4(PS)(2)(PS*)] with the monodentate coordination of one of the PS ligands. This indicates weaker hemilabile properties of phosphino-thioether ligands in the tungsten complexes. Consequently, both [1]PF6 and [2]PF6 exhibit significantly lower catalytic activity than the molybdenum analogues in the benchmark reaction of nitrobenzene reduction into aniline with Ph2SiH2. The DFT calculations were performed to determine the relative stability of possible isomers with the chelate, bridging and monodentate manner of coordination of the PS ligands to {M3S4} (M = Mo, W) clusters, taking (CH3)(2)PCH2CH2SCH3 as a model.