PCl3 Research Articles

A quantum chemical perspective on the potency of electron donors and acceptors in pnicogen bonds (AS...N, P...N, N...N).

A quantum chemical perspective of 31 structures contains electron acceptors: ASCl3 (arsenic trichloride), PCl3 (phosphorous trichloride) and NCl3 (nitrogen trichloride); forming non-covalent bond with various nitrogen-based electron donors that resulted in pnicogen bonds, AS...N, P...N and N...N were calculated at M062X/def2-QZVP level of theory. Besides the above method, MP2/def2-QZVP and CCSD(T)/def2-QZVP level of theories have also been analysed to have in depth knowledge about the bonds formed. The nature of the bonds was assumed from the electrostatic potential evaluated for all the monomers, where σ hole is positive for all the monomers. The strongest pnicogen bonds are ASCl3-NF2H, PCl3-NCH3CH3CH3 and NCl3-NCH3CH3CH3 having interaction energies as -4.15, -11.58 and -3.25 kcal/mol, respectively, at MP2/def2-QZVP level of theory. Further at CCSD(T)/def2-QZVP level of theory, ASCl3-NF2H and NCl3-NCH3CH3CH3 are found to be the most stable with interaction energies as -3.53 and -2.45 kcal/mol, respectively. The potential energy surface scan was performed for all the stable complexes in order to confirm the existences of energies are true minima. Moreover to confirm the halogen and pnicogen bonds, AIM analysis was carried out. The results from the above factors of pnicogen bond will help crystal growth, material science and engineering community to explore novel materials, which abide for modernization. Graphical abstract PCl3-NCH3CH3CH3 complex with 2.61 Å and pnicogen angle of 178.54° is strong, and interaction energy is -11.58 kcal/mol. Electron donors - ASCl3, PCl3 and NCl3 and electron acceptors -NCH3CH3CH3, NH3C2 and NHCO have strong electrostatic contribution. High and low values of (ρ) ∇2(ρ) reveal the strong and weak pnicogen bond. Schematic representation of acceptors surrounded by its donors and Electrostatic Potential map.

Features of the Identification of Trialkyl Phosphites in Reaction Mixtures and Their Characterization by Gas Chromatography–Mass Spectrometry

The interaction of aliphatic alcohols ROH with phosphorus trichloride in the absence of bases leads to the formation of exclusively dialkyl phosphonates (RO)2PHO. To obtain trialkyl phosphites (RO)3P, insufficiently described to date, the pH of the reaction mixtures was adjusted by adding N,N-dimethylaniline (pKa 5.1 ± 0.1). The identification of trialkyl phosphites directly in reaction mixtures without preparative isolation implies a joint consideration of their mass spectra and gas chromatographic retention indices, provided that all other components of such mixtures are identified. The need to comply with this condition has led to the identification of several homologues of a previously uncharacterized series of 2-alkoxy-1,3,2-dioxaphospholanes, formed from a random admixture of ethylene glycol. The use of such combined mass spectrometric parameters as homologous increments of retention indices helps to distinguish trialkyl phosphites from isobaric dialkyl phosphonates; the compounds of both series belong to the homologous group of y = 12, y ≡ M(mod14). Despite the absence of molecular ion signals in the electron ionization (EI) mass spectra, the molecular weights of trialkyl phosphites can be estimated. In addition, a comparison of the homologous increments of retention indices shows that, compared with dialkyl phosphonates, trialkyl phosphites are significantly less polar.

Determination of a semi-experimental equilibrium structure of 1-phosphapropyne from millimeter-wave spectroscopy of [formula omitted] and [formula omitted

Trideuterated 1-phosphapropyne (CD3CP) has been produced by co-pyrolysis of phosphorus trichloride and esadeuterated ethane. The rotational spectra of CD3CP in the ground and the low-lying vibrational states v8 (CCP bending mode) and 2 v8 have been investigated in the millimeter-wave region. Very accurate values of the quartic centrifugal distortion constants DJ and DJK and of the sextic distortion constants HJK and HKJ have been obtained for the ground state. l-type resonance effects have been taken into account in the analysis of the spectra of the degenerate bending states, so that the energy difference between the v8|l| = 20, and v8|l| = 22 states could be determined, together with a number of spectroscopic constants involved in the l-type resonance. Moreover, for the parent isotopologue CH3CP a new set of excited-state lines (v8 = 1, 2 and v4 = 1) were recorded up to 330 GHz, and a global analysis including all available rotational and rovibrational transitions related to the ground and v8 = 1, 2 states has been performed. A satisfactory fit could only be obtained by making a reassignment of the few transition wavenumbers previously measured for the 2ν80←ν8±1 hot band [M.K. Bane et al., J. Mol. Spectrosc.275 (2012) 9–14].The experimental work has been combined with quantum-chemical computations. Quadratic and cubic force constants of 1-phosphapropyne have been calculated at MP2 level of theory with a basis set of triple-ζ quality. A semi-experimental equilibrium structure has been derived by correcting experimental ground-state rotational constants by means of theoretical vibration-rotation interaction constants.

Post-synthetic efficient functionalization of polyaniline with phosphorus-containing groups. Effect of phosphorus on electrochemical properties

P-postmodified polyaniline was obtained by reacting phosphorus trichloride (PCl3) and chlorodiphenylphosphine (PPh2Cl) and polyaniline (PANI), under mild conditions. The reaction was found to be very selective, as only the imine groups were involved in the P-functionalization, and efficient as well, affording a P-loading of 3 at.% and 5 at.% for PPh2Cl and PCl3, respectively. All the polymers were characterized by different techniques and the results were endorsed by theoretical calculations. Experimental and Density Functional Theory results proved that the reaction occurs through the imine groups and the phosphorus atoms, generating NP bonds. The electrochemical properties of the NP modified materials were evaluated and the catalytic activity towards oxygen reduction reaction was measured. It was found that a high concentration of phenyl groups from PPh2Cl (about 3 at.%) affected negatively the activity of the catalyst since they prevented the access of the oxygen molecules to the catalytic active sites. However, a lower amount of PPh2 groups (1 at.%) or the use of PCl3 avoided this hindrance and resulted in an improved catalytic activity with respect to pristine PANI.

Synthesis, Identification and Studying Biological Activity of Some Heterocyclic Derivatives from 3, 5-Dinitrosalicylic Acid

The study deals with synthesizing new thiadiazole compound (2-(5-amino-1,3,4-thiadiaz0l-2-yl)-4,6-dinitrophenol)(1) by reaction of 3,5-dinitrosalicylic acid with thiosemicarbazide in Phosphoric chloride, then it is (1) reacted with 2-Bromobenzaldehydeto getting Schiff base (2-(5-((2-bromobenzylidene) amino)-1,3,4-thiadiaz0l-2-yl)-4,6-dinitrophenol)(2). T0he compound (2) will reacted with (chloroacetylchloride, thioglycolic acid, glycine, sodium azide, phthalic anhydride) to give (β-lactam, thiazolidine, imidazolidine, tetrazole, oxazepine) derivatives respectively. The new synthesized compounds have been identified by their melting points, 1H-NMR, 13C-NMR and FT-IR spectra. Then the biological activity studied for all the synthesized derivatives toward two type of bacteria.

Chromium(III) and Chromium(II) Phenolate Complexes with Bulky Alkylcyclopentadienyl Ligands

The chromium(II) tricarbonyl methyl complex [Cp′′′Cr(CO)3CH3] (1, Cp′′′ = η5‐C5H2tBu3‐1,2,4) was obtained from chromium hexacarbonyl, NaCp′′′, and methyl iodide. 1 was found to establish an equilibrium with the dicarbonyl acetyl isomer [Cp′′′Cr(CO)2(COCH3)] in solution via reversible, slightly endothermic methyl migration from chromium to a carbonyl ligand with ΔH ca. 3.6 kJ/mol and Ea ca. 49.5 kJ/mol. Phosphorus pentachloride oxidized 1 to the green, dinuclear tetrachloro complex [Cp′′′CrCl(µ‐Cl)]2 (2), which was crystallized as the blue‐green chromium(III) half sandwich complex [Cp′′′CrCl2(THF)] (3) in the presence of tetrahydrofuran vapor. Attempted sublimation of the known chromium(II) iodo complex [4CpCr(µ‐I)]2 resulted in a redox reaction with formation of the chromium(III) iodo dimer [4CpCrI(µ‐I)]2, whose tri(tert‐butyl)cyclopentadienyl derivative [Cp′′′CrI(µ‐I)]2 (4) could also be prepared by oxidation of [Cp′′′Cr(µ‐I)]2 with iodine. The chromium(III) bis(2,6‐diisopropylphenolate) complex [4CpCr(OC6H3iPr2‐2,6)2] (5) was obtained from chromium trichloride in a one pot reaction with sodium tetraisopropylcyclopentadienide, followed by sodium 2,6‐diisopropylphenolate. The chromium(III) starting compound 2 reacted with 2,6‐diisopropylphenolate to the Cp′′′ derivative [Cp′′′Cr(OC6H3iPr2‐2,6)2] (6). The chromium(II) starting compound [Cp′′′Cr(µ‐Br)]2 afforded the phenolate‐bridged chromium(II) dimer [Cp′′′Cr(µ‐OC6H5)]2 (7) upon treatment with sodium phenolate, while the product of the analogous reaction with 2,6‐di(tert‐butyl)phenolate was the mononuclear tetrahydrofuran adduct [Cp′′′Cr(OC6H3tBu2‐2,6)(THF)] (8).

ANTIMICROBIAL AND CHITINASE INHIBITORY ACTIVITIES OF 7-BENZAMIDOCOUMARINS

Objective: The aim of this study was to examine in vitro antimicrobial activity of a series of 7-benzamidocoumarin derivatives against three Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Bacillus pumilus), three Gram-negative bacteria (Escherichia coli, Klebsiella pneumonia, and Salmonella typhi), and three fungi (Candida albicans, Candida tropicalis, and Aspergillus niger) by 2-fold serial dilution method.
 Materials and Methods: The compounds were synthesized by amide coupling of 7-amino-4-methyl coumarin 5 and 7-amino-4-chloromethyl coumarin 6 with different aromatic acids 7 (a-h) and heteroaromatic acids 8 (i-j) in the presence of phosphorous trichloride as an acid catalyst in acetonitrile. The synthesized compounds were evaluated for antimicrobial and chitinase inhibitory activity.
 Results: Compounds 9, 11, 12, 21, and 23 showed good antibacterial activity with minimum inhibitory concentration (MIC) ranging from 6.25 to 50 μg/mL. Among them, compound 21 was the most active molecule with MIC 6.25 μg/mL against S. aureus and 6.25 μg/mL against, B. pumilus and S. typhi. Compounds 11 and 21 were the most potent antifungal candidates with MIC 6.25–25 μg/mL against C. albicans and C. tropicalis. All the compounds were also evaluated for their chitinase inhibitory property and among them; compound 9 emerged as strong inhibitor of the enzyme.
 Conclusion: Some of the compounds showed very good antimicrobial activities. Among these, compound 21 showing potent antimicrobial activities against five of the nine microbial strains examined in this study, was the most active compound of the series. Some of the compounds also showed chitinase inhibitory properties. This study also provides a starting point for investigating the structure-activity relationships (SARs) of synthetic 7-benzamidocoumarins.

Synthesis and Characterization of Itaconyl Chloride

Itaconyl chloride was synthesised using the bio-based itaconic acid (IA) and phosphorus pentachloride (PCl5) as raw material by a molten method. The effects of various main factors, i.e. The solvent effect on the quality of the product during the purifying process was studied. The ratio of raw materials, the vacuum distillation temperature and vacuum distillation time on itaconyl chloride preparation were investigated. The optimum conditions of synthesis were determined as f ollows: toluene as purified solvent, n(PCl5):n(IA) = 2.15:1, the vacuum distillation temperature 80 °C, the vacuum distillation time 2 h. The yield of itaconyl chloride could reach 90 % and its purity was more than 98 %. The structure of itaconyl chloride was confirmed by means of Fourier Transform Infra-Red (FT-IR) and Nuclear magnetic resonance hydrogen spectrum (1H-NMR).

Controlled polymerization of 3,4-dihydro-2H-1,3-benzoxazine and its properties tailored by Lewis acids

Polymerization reaction of a typical thermosetting benzoxazine monomer, BA-a, is tailored intentionally by particular Lewis acids including aluminium trichloride (AlCl3), phosphorus pentachloride (PCl5) and zinc chloride (ZnCl2), and polybenzoxazines with different crosslinking structures are obtained. Their rheological behaviors, polymerization mechanisms, chemical crosslinking structures and thermal properties are systematically studied. The results suggest that AlCl3 and PCl5 are much more efficient than ZnCl2 to affect the polymerization reaction of BA-a. PCl5 and AlCl3 can promote the generation of more carbocations, thus the polymerization of benzoxazine follows cationic chain polymerization mechanism. However, in the presence of less effective ZnCl2 or in the case of neat benzoxazine, the polymerization follows step polymerization mechanism. It is learned that the Lewis acids can promote crosslinking reaction of dangling arylamine benzene rings and form arylamine Mannich linkages that vary with the catalytic efficiency of the Lewis acids. As a result, the increase of impact strength by 36.4%, the increase of flexural strength by 243.4%, the increase of flexural modulus by 42% and the increase of char yield by 18.6% (absolute value) can be achieved by using different Lewis acids.

Convergent synthesis of phosphonopeptides via phospha-Mannich reactions: Rationale on reactivity and mechanistic insights

Phospha-Mannich reactions of benzyl carbamate, aldehydes, and methyl dichlorophosphite followed by aminolysis with amino acid esters or alcoholysis with hydroxyl acid esters produce N-Cbz(benzyloxycarbonyl)-protected phosphonopeptides or phosphonodepsipeptides. However, similar reactions do not work when Cbz-amino amides are used instead of the carbamate. Phospha-Mannich reactions of N-Cbz-amino amides/2-(Cbz-amino)alkanesulfonamides, aldehydes, and dichloroarylphosphines and subsequent aminolysis with amino acid esters or alcoholysis with hydroxyl acid esters yield phosphinopeptides or phosphinodepsipeptides and hybrid sulfonophosphinopeptides or sulfonophosphinodepsipeptides. The different reactivities and mechanistic insights are rationalized that the α-amino alcohols generated from aldehydes and amides/sulfonamides show weaker nucleophilicity than those generated from aldehydes and benzyl carbamate. They can react with stronger electrophilic dichloroarylphosphines rather than weaker electrophilic methyl dichlorophosphite. The nucleophilicity of α-amino alcohols (amine reagents, carbamates, amides, and sulfonamides) and the electrophilicity of phosphorus reagents (dichloroarylphosphines and ethyl dichlorophosphite) control the reactivity of the phospha-Mannich reactions. Phosphorus trichloride is also efficient phosphorus reagent in the phospha-Mannich reactions because it is stronger electrophile as well.

A Study on the Synthesis of Risedronic Acid: The Role of an Ionic Liquid Additive

Background: The synthesis of high value risedronic acid is not fully resolved, as, for the time being, the best method based on the preparation from 3-pyridylcarboxylic acid by reaction with phosphorus trichloride in methanesulfonic acid gives risedronic acid in a good yield, but in an unpure form. Methods: Alternative protocols realizing the synthesis in sulfolane as the solvent and/or in the presence of suitable IL additive were developed to obtain the target dronic acid in a pure form. Results & Conclusion: Using phosphorus trichloride and phosphorous acid in two equivalents quantities together with 0.6 equivalents of [bmim][BF4] without any solvent, the method afforded the target dronic acid in a yield of 66% in a pure form.

Rational synthesis of α-hydroxyphosphonic derivatives including dronic acids

New, green methods have been elaborated for the syntheses of α-hydroxyphosphonates and α-hydroxymethylenebisphosphonic derivatives (HMBPs, dronates). α-Hydroxyphosphonates were prepared via the Pudovik reaction, while the synthesis of HMBPs has been performed in the three-component reaction of carboxylic acids, phosphorus trichloride and phosphorus acid.

Reaction of lithiated thiophene-derived aminocarbene complexes with inorganic halides: Preparation of a heteroatom containing mono- and multicarbene complexes

The reaction of lithiated pentacarbonyl [(N,N-dimethylamino) (2-thienyl)carbene]chromium (0) or pentacarbonyl [(N,N-dimethylamino) (2-thienyl)carbene]tungsten (0) with SOCl2, COCl2, Me3SiCl, Me2SiCl2, Me3SnCl and SnCl4 afforded the corresponding carbene complexes, in which the chlorine was substituted with a 2-thienyl amino carbene moiety. Reaction with S2Cl2 afforded the corresponding biscarbene sulphide. In contrast, reactions with the phosphorous chlorides PCl3, POCl3, PhPCl2 and Ph2PCl were unsuccessful. The trimethylstannyl derivative was successfully used in Stille coupling with 4-nitroiodobenzene. The molecular structure of the tungsten tetracarbene derived from SnCl4 was obtained.

Challenges and solutions in phosphinate chemistry

Abstract Several major challenges still remain in organophosphorus chemistry. Organophosphorus compounds are currently synthesized from phosphorus trichloride (PCl3), even though the final consumer products (such as pesticides, flame-retardants, extractants) do not contain reactive phosphorus-chlorine bonds. In order to bypass phosphorus trichloride, significant interest has been devoted to functionalizing elemental phosphorus (P4, the precursor to PCl3), red phosphorus (Pred), or phosphine (PH3). Yet, phosphinates (ROP(O)H2) are already available on an industrial scale and are the most environmentally benign, but their use as phosphorus trichloride replacements has been completely overlooked until a few years ago. An overview of some of the methodologies developed in my laboratory for P–C and P–O bond-forming reactions through phosphinate chemistry, as well as some selected applications, are presented. Another significant challenge remains the synthesis of P-stereogenic compounds. My group’s recent progress in this area is also discussed. Based on menthol as an inexpensive chiral auxiliary, various menthyl phosphinates can be synthesized. These phosphinates are precursor to P-stereogenic phosphines through well-established literature transformations.

Practical Deoxygenation of Oxazole N-Oxides by PCl3/Collidine

A new chemoselective method for the synthesis of 2-aryl-1,3-oxazoles by deoxygenation of the corresponding N-oxides has been developed. As the deoxygenation reagent, a previously unknown complex of collidine with phosphorus trichloride in a 2:1 ratio has been used. The developed method enabled the preparation of a wide range of 2-aryl-1,3-oxazoles comprising various functional groups in good yields. The advantage of this reagent is its tolerance to nitro, methyl, hydroxyl, formyl, and acetyl groups, and double bonds. Due to chemoselectivity and availability of reagents, the method may be used for deoxygenation of N-oxides of other heterocyclic compounds (thiazole, pyridine, quinoline, etc.).

2H-Benzo[e]-1,2-oxaphosphorine Related Heterocycles as Precursors for the Synthesis of Unsymmetrical Bicyclic Phosphonates

The reaction of 2-hydroxy-5,7,8-trimethyl-2-oxobenzo[e]-1,2-oxaphosphorine with thionyl chloride yielded the pyrophosphonate product, which was isolated and characterized for the first time. Subsequent treatment of it with phosphorus pentachloride led to the formation of new types of unsymmetrical cage phosphonates.

Bulk Phosphorus-Doped Graphitic Carbon

A direct synthetic route to a tunable range of phosphorus-doped graphitic carbon materials is demonstrated via the reaction of benzene and phosphorus trichloride in a closed reactor at elevated temperatures (800–1050 °C). Graphitic materials of continuously variable composition PCx up to a limit of approximately x = 5 are accessible, where phosphorus is incorporated both substitutionally within the graphite lattice and as stabilized P4 molecules. Higher temperatures result in a more ordered graphitic lattice, while the maximum phosphorus content is not observed to diminish. Lower temperatures and higher initial phosphorus content in the reaction mixture are shown to correlate with higher structural disorder. Phosphorus incorporation within directly synthesized PCx, as both a substitutional dopant and in the form of interstitial, stabilized molecular P4, is demonstrated to occur with little oxygen contamination in the bulk (<4 atom %), motivating promising future applications in fuel cells and alkali metal...

Direct, oxidative halogenation of diaryl- or dialkylphosphine oxides with (dihaloiodo)arenes

The oxidative halogenation of diaryl- or dialkylphosphine oxides with the hypervalent iodine reagents (difluoroiodo)toluene (p-TolIF2, 1) and (dichloroiodo)benzene (PhICl2, 2) is reported. Phosphoric fluorides could be recovered in 32–75% yield, or they could be trapped with EtOH to give the corresponding phosphinate in typically good yield. Phosphoric chlorides were not readily isolable, and were trapped with alcohol and amine nucleophiles, giving diaryl- or dialkylphos-phinates and phosphinamides in up to 90% yield.

Phosphorus Pentachloride Promoted gem-Dichlorination of 2'- and 3'-Deoxynucleosides.

Halogen substitution at various positions of canonical nucleosides has generated a number of bioactive structural variants. Herein, the synthesis of two unique series of sugar modified nucleosides bearing a gem-dichloro group is presented. The synthetic plan entails the controlled addition of phosphorus pentachloride to suitably protected 2′- or 3′-ketodeoxynucleoside intermediates as the key step, facilitating the rapid construction of such functionalized molecules. Under the same reaction conditions, the highest chemoselectivity was observed for the formation of 2′,2′-dichloro-2′,3′-dideoxynucleosides, while a competing 2′,3′-elimination process occurred in the case of the 3′,3′-dichloro counterparts.

Synthesis of Secondary Phosphine Oxides by Substitution at Phosphorus by Grignard Reagents

Secondary phosphine oxides (SPOs) are important starting materials in organophosphorus syntheses, and may be the ligands in transition metal complexes. SPOs are obtained from phosphorus trichloride via double substitution by a Grignard reagent followed by hydrolysis, or from dialkyl phosphites by reaction with two equivalents of a Grignard reagent. The preparation of SPOs with two different substituents is of special importance. This minireview gives useful hints for the synthesis of a variety of SPOs that are useful intermediates. Keywords: Dialkyl phosphites, grignard reagents, P(III)-chlorides, secondary phosphine oxides, substitution, ligand.