Conformational Analysis of the 1,3‐Oxaphosphorinanes Formed from α,β‐Unsaturated Aldehydes and the (Hydroxymethyl)phosphines RP(CH2OH)2 (R = Ph or CH2OH)

Equimolar reactions of cinnamaldehyde or its 3,5‐dimethoxy‐4‐hydroxy derivative (sinapaldehyde) with RP(CH₂OH)₂ (R = Ph or CH₂OH) were studied in MeOH or CD₃OD at room temperature by NMR spectroscopy. In MeOH, nucleophilic attack of the phosphine at the C?C bond, with concomitant loss of CH₂O, affords the tertiary phosphine HOCH₂P(R)CH(Ar)CH₂CHO ( 3 ) that rapidly converts mainly into a 1,3‐oxaphosphorinane derivative ( 5 ) formed as a mixture of four diastereomers. Conformational analysis reveals that the Ar group in these is exclusively in an equatorial position while the OH and R groups can be equatorial‐oriented or axial‐oriented. In CD₃OD, 1,3‐oxaphosphorinanes monodeuterated in the C5 position are obtained as a mixture of eight diastereomers where the dominate diastereomers have an axial D‐atom. Diastereomeric ratios depend on the nature of the Ar and R groups.     

Chemistry and stereochemistry of the interaction of the water-soluble phosphine [HO(CH2)3]3P with cinnamaldehyde in aqueous media

To learn more about the bleaching action of pulps by (hydroxymethyl)phosphines, cinnamaldehyde was reacted with tris(3-hydroxypropyl)phosphine, [HO(CH2)3]3P (THPP), in aqueous solution at room temperature under argon. Self-condensation of the aldehyde into two isomeric products, 2-benzyl-5-phenyl-pent-2,4-dienal and 5-phenyl-2-(phenylmethylene)-4-pentenal, is observed; this implies initial nucleophilic attack of the phosphine at the beta-carbon of the alpha,beta-unsaturated aldehyde. Reaction in D2O gives the same products in which all but the phenyl and CHO protons are replaced by deuterons. NMR studies are consistent with carbanion formation and subsequent condensation of two phosphonium-containing aldehyde moieties to generate the products with concomitant elimination of phosphine oxide. In D2O in the presence of HCl, THPP reversibly attacks the aldehyde-C atom to form the (alpha-hydroxy)phosphonium derivative [PhCH=C(H)CH(OD)PR3]Cl (where R=(CH2)3OD), which slowly converts into the deuterated bisphosphonium salt [R3PCH(Ph)CD(H)CH(OD)PR3]Cl2 via the deuterated monophosphonium salt [R3PCH(Ph)CD(H)CHO]Cl. The phosphonium intermediates and phosphonium products in this chemistry, although having up to three chiral carbon centers, are formed with high stereoselectivity just in enantiomeric forms. In acetone-H2O (1:1 v/v), a cross-condensation of cinnamaldehyde with acetone to give 6-phenyl-3,5-hexadien-2-one is promoted by THPP via generation of OH-.     

Deuterium Isotope Effect on Excess Enthalpies of Methanol or Ethanol and Their Deuterium Derivatives at 298.15 K

Excess enthalpies of six binary mixtures of CH₃ OD+CH₃ OH, CH₃ OD+CD₃ OD, CD₃ OD+CH₃ OH, C₂ D₅ OD+C₂ H₅ OH, C₂ D₅ OD+C₂ H₅ OD, C₂ H₅ OD+C₂ H₅ OH have been determined over the whole range of mole fractions at 298.15 K in order to know the isotopic effect on hydrogen-bonding accurately, although there are many reports on the differences in the strength of hydrogen-bonding between OH and OD. All excess enthalpies measured are very small and endothermic. The mixtures of CH₃ OD+ CH₃ OH, and C₂ D₅ OD+C₂ H₅ OH showed the largest excess enthalpies among each methanol and ethanol mixtures. The difference of intermolecular interaction between OH and OD in methanol and ethanol was almost same value of (1.82±0.04) J mol^-1 Excess enthalpies of 1,4-dimethylbenzene+1,3-dimethylbenzene and 1,4-dimethylbenzene+1,2-methylbenzene were measured by three different principle calorimeters at 298.15 K in order to know the precision of calorimetry for a small enthalpy change. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of isotope substitution on the magnitude of nonequilibrium nuclear polarization in photolysis of acetone in methanol

Polarization of nuclei in both the products of the reactions and in the CHD₂OD proton without polarization in the CH₃OH protons is observed in irradiation of a solution of acetone in CD₃OD in the presence of CHD₂OD and CH₃OH. Polarization of the protons of the products is strongly dependent on the temperature of the solution and arises in radical pairs; polarization of the proton of partially deuterated methyl alcohol is due to a mechanism of optical nuclear polarization. It was hypothesized that the isotope effect is due to a difference in proton and electron relaxation and to a difference in the rates of cross-relaxation transitions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2683–2687, December, 1989.     

A novel water-soluble sulfide cluster of iron: synthesis,properties, and intercalation into molybdenum disulfide

A novel water-soluble sulfide cluster of iron, {Fe₆S₈[P(CH₂OH)₃]₆}²⁺, was obtained from ferrous chloride tetrahydrate, tris(hydroxymethyl)phosphine, and H₂S in methanol. A reaction of the cluster in solution with dispersed molybdenum disulfide gave an inclusion compound, MoS₂({Fe₆S₈[P(CH₂OH)₃]₆}Cl₂)_0.06. The products obtained were characterized by IR, NMR, and ESR spectroscopy, electronic absorption spectroscopy, mass spectrometry, and elemental analysis. The magnetic susceptibility of the cluster was studied in solution and in a molybdenum disulfide matrix.     

Volumetric properties of mixtures of water and methanol H/D-isotopomers between 5 and 45°C

Densities of H/D-isotopomers mixtures of water (H₂O, D₂O) and methanol (CH₃OH, CD₃OH, CH₃OD, and CD₃OD) over the full range of compositions were measured at 5, 15, 25, 35, and 45°C. Results have been used to calculate molar volumes, excess molar volumes, apparent molar volumes, and isotope effects of the mixtures. The volumetric properties are discussed in terms of the structural changes in water-methanol solutions under the influence of isotope substitution.     

Effect of strongly interacting solutes on group rotational correlation functions in ethanol

Proton magnetic relaxation rates of solutions of LiCl and LiI in isotopically labelled ethanols CH₃CD₃OD, CD₃CH₂OD and CD₃CD₂OH have been measured as functions of temperature and concentration mostly at v=30 MHz, where 21. The data were reduced in a way that revealed that CH₃ and CH₂ relaxation curves contained a residuum from the slow motion of the OH group in many cases. Thus, the rotational time correlation function of the CH₃ and CH₂ groups contain a residuum term stemming from the slow motion within the same molecule. The data show a threshold of the rotational energy which has to be exceeded in order to make the effect observable.     

Effets Isotopiques dans la Fragmentation par Impact Électronique de Méthanols Deutériés

The mass spectra of the CH₃OH, CH₂DOH, CD₃OH, CH₃OD and CD₃OD methanols have been recorded at nominal electron energies ranging from 11 to 35 eV. Curves are given for the variation of the isotope effects related to the molecular ion stability and bond cleavage probabilities as a function of the electron energy, and are compared with a priori calculations. A simple distribution function and a value for the number of oscillators equal to half the theoretical figure give fairly satisfactory agreement, except as concerns the molecular ion stability. The form of the curves for the latter could be explained by the existence of an electronic state of the molecular ion other than the ground state.     

Investigation on pyran and related compounds

A convenient method for obtaining 4-aminocoumarins by the reaction of 4-chlorocoumarin with amines in dimethyl sulfoxide is proposed. The reactions of 4-chlorocoumarin with CD₃ONa in CD₃OD and with [N-D₁]piperidine, of [3-D₁]-4-chlorocoumarin with CH₃ONa in CH₃OH and with aniline and n-butylamine and of 4-methoxycoumarin with CD₃ONa in CD₃OD have been studied and the mechanism of nucleophilic and substitution in position 4 of the coumarin system is discussed.For Communication XLI, see [11].Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 8, pp. 1019–1023, August, 1970.     

Kinetics of the reaction of OH radicals with CH3OH and CD3OD studied by laser photolysis coupled to high repetition rate laser induced fluorescence

A new experimental set-up coupling laser photolysis to a 10 kHz dye laser as the excitation source for OH fluorescence has been validated by measuring the rate constant of the reaction CH₃OH + OH. The rate constant of the deuterated homologue CD₃OD + OH has been measured under the same conditions.     

Syntheses and rearrangements of tris(hydroxymethyl)phosphine and tetrakis(hydroxymethyl)phosphonium salts

Abstract

Tetrakis(hydroxymethyl)phosphonium (HOCH₂)₄P⁺ salts, particularly the chloride (THPC) and sulfate (THPS), are among the most accessible organophosphorus compounds that can be made quantitatively from PH₃ and formaldehyde in aqueous media under ambient conditions. These phosphonium salts are air-stable, and are widely used as reactants in organic syntheses, as well as in textile or oil industries. Synthesis of tris(hydroxymethyl)phosphine (THP), an active component of the salts, is more complicated because direct synthesis from PH₃ and CH₂O requires either pressure and high temperature, at which THP rearranges into bis(hydroxymethyl)methylphosphine oxide, CH₃P(O)(CH₂OH)₂, or a metal catalyst that is usually difficult or impossible to recover. Syntheses of THP based on neutralization of the salts are more convenient but require pH control and additional steps to separate THP from CH₂O. This review summarizes literature data on syntheses and purification of the salts and THP, and side reactions such as thermal rearrangement and oxidation.     

Developments in the chemistry of tris(hydroxymethyl)phosphine

Tris(hydroxymethyl)phosphine, P(CH₂OH)₃, a water-soluble compound, has been known for about 50 years but development of its coordination chemistry has been slow and relatively recent. During some collaborative studies with a pulp and paper research institute on testing water-soluble catalysts for hydrogenation of lignin in pulp and the unsaturated functionalities in lignin model compounds, with the aim of bleaching pulps, we discovered new, in situ, Ru-P(CH₂OH)₃ hydrogenation catalysts. Interest in the coordination chemistry of this phosphine thus ensued, and this review covers this topic as well as the coordination chemistry of a diphosphine analogue, bis[bis(hydroxymethyl)phosphino]ethane, (HOCH₂)₂P(CH₂)₂P(CH₂OH)₂. The applications of the water-soluble metal complexes of these two phosphines in the areas of catalysis and medicinal drugs are also described. These phosphines, in the absence of metals, were found serendipitously to be effective bleaching agents for pulps (and also brightness stabilizing agents), and some relevant organo-phosphorus chemistry from our group is also briefly presented, particularly because of its possible significance in hydroformylation and hydrogenation processes catalyzed by metal–phosphine complexes.     

Angular dependence of 1H- and 2H-NMR spectra of water and methanol absorbed in cellulose triacetate film

¹H- and ²H-NMR spectra of water (H₂O and D₂O) and methanol (CH₃OD and CD₃OH) absorbed in cellulose triacetate films have been observed as a function of the angle θ between the film surface and the magnetic field. ¹H-NMR signals of H₂O and CH₃OD are doublets and triplets due to dipole interactions, respectively. ²H-NMR signals of D₂O, CD₃OH, and CH₃OD are doublets due to quadrupole splittings. The magnitudes of these splittings change depending on θ. The analysis of the angle-dependent patterns indicates that the motionally averaged axes of the dipole and the quadrupole moments orient in the direction perpendicular to the film surface. The alignment of water and/or methanol molecules originates from the film morphology, which is anisotropic in the perpendicular direction. From the angle dependence of the chemical shift, the volume diamagnetic susceptibility of the film is estimated to be 0.44 ppm.     

Chromatographic performance of deuterated solvents in reversed phase micro high performance liquid chromatography

The chromatographic performance of the deuterated solvents, CD₃OD and D₂O, has been investigated in reversed-phase micro high performance liquid chromatography. The chromatographic performance of CD₃OD is only slightly superior to that of CH₃OH. However, the performance of D₂ is significantly superior to that of H₂O, separation of aromatics being improved by about 30%. D₂ is a particularly powerful solvent for the separation iof deuterated and non-deuterated compounds.     

Kinetics of the ?OH-radical initiated reactions of acetic acid and its deuterated isomers

Kinetics of the ^•OH-initiated reactions of acetic acid and its deuterated isomers have been investigated performing simulation chamber experiments at T = 300 ± 2 K. The following rate constant values have been obtained (± 1σ, in cm³ molecule⁻¹ s⁻¹): k ₁(CH₃C(O)OH + ^•OH) = (6.3 ± 0.9) × 10⁻¹³, k ₂(CH₃C(O)OD + ^•OH) = (1.5 ± 0.3) × 10⁻¹³, k ₃(CD₃C(O)OH + ^•OH) = (6.3 ± 0.9) × 10⁻¹³, and k ₄(CD₃C(O)OD + ^•OH) = (0.90 ± 0.1) × 10⁻¹³. This study presents the first data on k ₂(CH₃C(O)OD + ^•OH). Glyoxylic acid has been detected among the products confirming the fate of the ^•CH₂C(O)OH radical as suggested by recent theoretical studies.     

Mechanism of noncatalytic synthesis of tris(hydroxymethyl)phosphine. Nonempirical quantum-chemical approach

The gas-phase reaction of the synthesis of tris(hydroxymethyl)phosphine from phosphine and formaldehyde was studied using a calculation scheme based on the density functional theory with hybrid exchange-correlation functional B3LYP in the 6–311++G** basis. The reaction was shown to proceed with the participation of unstable intermediates containing three-membered ring. The transformation into final products includes opening of the three-membered ring and intramolecular proton transfer. The results can be useful at selecting catalysts and for explaining the mechanism of the catalytic reaction of tris(hydroxymethyl)phosphine synthesis.     

Effect of H/D isotope substitution on polarizability of methanol molecules

The electron polarizabilities (α₀·10²⁴/cm³ molec.⁻¹) were estimated from the data on refractive indices and molar volumes of H/D isotopomers of methanol at 25 °C using the Lorentz-Lorentz formula: 3.265 (CH₃OH), 3.260 (CH₃OD), 3.235 (CD₃OH), and 3.231 (CD₃OD). A relationship between the isotope effects for α₀ and volume (packing) changes in the structure of liquid methanol induced by deuterosubstitution in the methanol molecule was proposed. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1927–1928, August, 2005.     

A Solvent Switch for the Stabilization of Multiple Hemiacetals on an Inorganic Platform: Role of Supramolecular Interactions

Reaction of Zn(OAc)₂ ? 2 H₂O with 2,6‐diisopropylphenyl phosphate (dippH₂) in the presence of pyridine‐4‐carboxaldehyde (Py‐4‐CHO) in methanol resulted in the isolation of a tetrameric zinc phosphate cluster [Zn(dipp)(Py‐4‐CH(OH)(OMe))]₄ ? 4 MeOH ( 1 ) with four hemiacetal moieties stabilized on the double‐4‐ring inorganic cubane cluster. The change of solvent from methanol to acetonitrile leads to the formation of [Zn(dipp)(Py‐4‐CHO)]₄ ( 2 ), in which the coordinated Py‐4‐CHO retains its aldehydic form. Dissolution of 1 in CD₃CN readily converts it to the aldehydic form and yields 2 . Similarly 2 , which exists in the aldehyde form in CD₃CN, readily converts to the hemiacetal form in CD₃OD/CH₃OH. Compound 1 is an unprecedented example in which four hemiacetals have been stabilized on a single molecule in the solid state retaining its stability in solution as revealed by its ¹H NMR spectrum in CD₃OD. The solution stability of 1 and 2 has further been confirmed by ESI‐MS studies. To generalize the stabilization of multiple hemiacetals on a single double‐four‐ring platform, pyridine‐2‐carboxaldehyde (Py‐2‐CHO) was used as the auxiliary ligand in the reaction between zinc acetate and dippH₂, leading to isolation of [Zn(dipp)(Py‐2‐CH(OH)(OMe))]₄ ( 3 ). Understandably, recrystallization of 3 from acetonitrile yields the parent aldehydic form, [Zn(dipp)(Py‐2‐CHO)]₄ ( 4 ). Single‐crystal X‐ray diffraction studies reveal that supramolecular bonding, aided by hydrogen‐bonding interactions involving the hemiacetal functionalities (C?OH, C?OMe, and C?H), are responsible for the observed stabilization. The hemiacetal/aldehyde groups in 1 and 2 readily react with p‐toluidine, 2,6‐dimethylaniline, and 4‐bromoaniline to yield the corresponding tetra‐Schiff base ligands, [Zn(dipp)(L)]₄ (L=4‐methyl‐N‐(pyridin‐4‐ylmethylidene)aniline ( 5 ), 2,6‐dimethyl‐N‐(pyridin‐4‐ylmethylene)‐aniline ( 6 ), and 4‐bromo‐N‐(pyridin‐4‐ylmethylene)aniline ( 7 )). Isolation of 5 – 7 opens up further possibilities of using 1 and 2 as new supramolecular synthons and ligands.     

Organic Phosphorus Compounds 52. Preparation and properties of β-hydroxyalkyl-phosphonium salts and tertiary phosphine oxides

The new, tris- (2- hydroxyalkyl) - (hydroxymethyl) - phosphonium salts: [(RCHOHCH₂)₃ PCH₂OH]Cl (I, R = ClCH₂; III, R = CH₃) are formed in high yield by reaction of tetrakis-(hydroxymethyl)-phosphonium chloride (Tetrakis) with epoxides under basic conditions. Under the same conditions, styrene oxide yields only the disubstituted product, [(PhCHOHCH₂)₂ (CH₂OH)₂P]Cl. Optimal pH values for the reactions are 8 to 9; at lower pH the conversion is too slow; at a higher pH, oxidative decomposition of the salts occurs. Conversion of the salts to tertiary phosphine oxides (RCHOHCH₂)₃P ? O (R ? ClCH₂; CH₃) with loss of the hydroxymethyl group is best carried out with chlorine at pH 5 to 7. The yields are usually 60 to 90%.     

Quantum-chemical investigation of thermal transformations of tris(hydroxymethyl)phosphine

In keeping with the calculations of thermodynamic characteristics of possible transformations of tris(hydroxymethyl)phosphine in the framework of DFT-approach using hybrid exchange-correlation functional B3LYP with the basis 6–311++G** the probability of transformation of tris(hydroxymethyl)phosphine at the temperature below 350 K into methylbis(hydroxymethyl)phosphine oxide is higher than the conversion into methyl(hydroxymethyl)phosphine oxide, and at the temperature over 350 K the trend is opposite. The probability of the formation of a heterocyclic dimer at the temperature over 300 K is somewhat lower and of bis(hydroxymethyl)phosphine in the temperature range 250–550 K is significantly lower.