Novel nonionic siloxane surfactants

A new method for ethoxylation without application of pressure is described. Butynediololigo(oxyethylene) [H(OCH₂CH₂)_n? OCH₂? C?C? CH₂O(CH₂CH₂O)_nH with n=1–16] has been prepared in the presence of an electrophilic catalyst in a specially developed reciruculating apparatus. The products have been characterized by NMR and IR spectroscopy. New nonionic silicone surfactants have been synthesized by hydrosilylation of these butynediololigo(oxyethylenes) with defined siloxanes and polysiloxanes. Protection of the hydroxyl group before hydrosilylation was not necessary. Hydrosilylation was carried out in the presence of a solvent. It has been possible to obtain surfactants with a surface tension of about 21-22 mN m^?1 and an interfacial tension of 2 mN m^?1.     

Ab initio studies of structural features not easily amenable to experiment. 25. Conformational analysis of methyl propanoate and comparison with the methyl ester of glycine

The molecular geometries of three conformations of methyl propanoate (MEP) (C? C? C?O torsions of 0°, 120°, and 180°) and the potential-energy surfaces of MEP (C? C? C?O torsions) and of the methyl ester of glycine (MEG) (N? C? C?O torsions) have been determined by ab initio gradient calculations at the 4-21G level. MEP has conformational energy minima at 0° and 120° of the C? C? C?O torsion, while the 60–90° range and 180° are energy maxima. For MEG there are two minima (at 0° and 180°) and one barrier to N? C? C?O rotation in the 60–90° range. The N? C? C?O barrier height is about twice as high (4 kcal/mol) as the C? C? C?O barrier. The 180° N? C? C?O minimum is characteristically wide and flat allowing for considerable flexibility of the N? C? C?O torsion in the 150–210° range. This flexibility could be of potential importance for polypeptide systems, since the N? C? C?O angles of helical forms are usually found in this region. The molecular structures of the methyl ester group CH₃OC(?O)CHRR′ in several systems are compared and found to be rather constant when R ? H and R′ ? H, CH₃, CH₃CH₂; or when R ? NH₂ and R′ ? H, CH₃, or CH(CH₃)₂.     

Synthesis of polyphosphazenes bearing alkoxyethoxy and trifluoroethoxy groups

The synthesis of various phosphoranimines including (CH₃OCH₂CH₂O) (CF₃CH₂O)₂P?N? Si(CH₃)₃, (CH₃OCH₂CH₂OCH₂CH₂O) (CF₃CH₂O)₂P?N? Si (CH₃)₃, (CH₃OCH₂CH₂O)₂(CF₃CH₂O) P?N? Si(CH₃)₃, and (CH₃OCH₂CH₂OCH₂CH₂O)(CF₃CH₂O) P?N? Si(CH₃)₃ via the Staudinger reaction of (CH₃)₃SiN₃ with the suitably substituted phosphite is reported. These monomers were polymerized using tetra-n-butylammonium fluoride and N-methylimidazole in various solvents at several temperatures. In situ ³¹P-NMR kinetic studies and M_n versus time studies were also performed for the monomers to understand the propagation mechanism. © 1994 John Wiley & Sons, Inc.     

Molecular mechanics assessment of the configurational statistics of polyoxyethylene

Previous investigators have shown that statistical mechanical averages for configuration-dependent physical properties of long unperturbed polyoxyethylene chains are sensitive to the gauche–trans energy difference for rotation about C? C bonds. Agreement between theory and experiment could be obtained only by significant adjustment of this energy away from values predicted by semiempirical conformational energy computations. The present work examines the success of MM 2 in evaluating conformational properties of long unperturbed polyoxyethylene chains. Calculations are performed which identify the rotational isomers, and their energies, for the indicated bonds in CH₃OCH₂CH₂O? CH₂? CH₂? OCH₂CH₂OCH₃. These energies are used to assign statistical weights utilized in the configuration partition function for a rotational isomeric state chain with symmetric threefold interdependent rotations. The customary generator matrix scheme is employed to evaluate the mean-square unperturbed end-to-end distance, mean-square unperturbed dipole moment, and their temperature coefficients. Contrary to computational schemes employed previously, MM 2 is found to provide an estimate of the gauche–trans energy difference for rotation about C? C which is in harmony with the known dimensions and dipole moments of the unperturbed polymer. MM 2 also provides good estimates for most of the other parameters required in the rotational isomeric state treatment. A notable exception is provided by the gauche–trans energy difference for rotation about the C? O bond. This energy difference is overestimated by MM 2.     

Conformational analysis of poly(oxyethylene) chain in aqueous solution as a hydrophilic moiety of nonionic surfactants

Conformational states of poly(oxyethylene) chain in aqueous solution are examined in connection with hydrophilic property of nonionic surfactants. The Raman spectra in various states are analyzed on the basis of comprehensive normal coordinate treatment. The poly(oxyethylene) chain is more ordered in more dilute aqueous solution. This conformational ordering is further promoted by lowering temperature. The ordered structure, which is similar, at least in part, to that in the solid state, is substantiated by the hydrogen bonds making the gauche conformation of the OCH₂-CH₂O group more favorable. The hydration has no significant effect on the conformation of the CH₂O-CH₂CH₂ group.     

Easily available niobium(V) mixed chloro‐alkoxide complexes as catalytic precursors for ethylene polymerization

The dinuclear [NbCl_n(OR)_(5‐n)]₂ (n = 4, R = Et, 1 ; n = 4, R = CH₂Ph, 2 ; n = 3, R = Et, 3 ; n = 2, R = Et, 4 ; n = 2, R = , 5 ), and [Nb(OEt)₅]₂, 6 , and the mononuclear niobium compounds NbCl₄[κ²? OCH₂CH(R′)OR] (R = Me, R′ = H, 7 ; R = Et, R′ = H, 8 ; R = CH₂Cl, R′ = H, 9 ; R = CH₂CH₂OMe, R′ = H, 10 ; R = R′ = Me, 11 ), NbBr₄[κ²? OCH₂CH₂OMe], 12 , and NbCl₃(κ²? OCH₂CH₂OMe)(κ¹? OCH₂CH₂OMe), 13 , were tested in ethylene polymerization. Optimized reaction conditions included the use of D‐MAO as co‐catalyst and chlorobenzene as solvent at 50 °C. Complex 7 , whose X‐Ray structure is described here for the first time, exhibited the highest activity ever reported for a niobium catalyst in alkene polymerization [151 kg_polymer × mol_Nb^?1 × h^?1 × bar^?1]. Compounds 1 , 3‐5 , 8 , 13 showed activities similar to that of 7 . Linear polyethylenes (characterized by FT‐IR, NMR, GPC, and DSC analyses) with a broad polydispersivity were obtained. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Conformational preferences of some substituted methyl groups in cyclohexanes as studied by carbon-13 nuclear magnetic resonance

Low temperature ¹³C NMR spectra of 80:20 mixtures of cis and trans-4? CH₃? CH₃? C₆H₁₀CH₂X, where ? C₆H₁₀-is 1, 4-disubtituted cyclohexyl and X=Br, CN, OH, OCH₃, Si(CH₃)₃, Sn(CH₃)₃, Pb(CH₃)₃ and HgOCOCH₃ have been recorded. The signals of the trans (e, e) components were assigned from the ambient temperature spectra of C₆H₁₁CH₂X and the established substituent effects of an equatorial methyl group in cyclohexane. Conformational equilibria of the cis (e, a?a, e) components were then computed from the intensities of the (remaining) signals (～180 K) of the two conformational isomers. From these equilibria A values of CH₂X were calculated, assuming additivity of conformational energies of CH₃ and CH₂X (the counter-poise approach). In general, these values are very similar to the value of the CH₃, although some trends do emerge. This study provides α, β, γ, and δ effects for a wide range of axial and equatorial ? CH₂X groups.     

Anionic ring opening polymerization of cyclotetrasiloxanes with large substituents

Cyclotetrasiloxanes with large substituents were synthesized by hydrosilylation of 1,3,5,7-tetramethylcyclotetrasiloxane with CH₂=CHCH₂X, X being (CH₂)₂CH₃, O(CH₂CH₂O)₃CH₃, OCH₂epoxy and OCH₂- benzo-18-crown-6. The tetrasubstituted cycles were homo-polymerized or copolymerized with octamethylcyclotetrasiloxane in the presence of potassium silanolate to yield polysiloxanes with side chains containing oxirane rings, crown ethers or oxyethylene ligands. In addition to a complex mixture of cycles, about 50 to 80% polymer can be recovered. The copolymer generally contains less of the substituted monomer than the starting monomer feed, but the bulky substituents do not appear to prevent formation of homo- or copolymer.     

Density functional theory investigation of the binding interactions between phosphoryl,carbonyl, imino,and thiocarbonyl ligands and the pentaaqua nickel(II) complex: Coordination affinity and associated parameters

Density Functional Theory (UB3LYP/6‐311++G(d,p)) calculations of the affinity of the pentaaqua nickel(II) complex for a set of phosphoryl [O?P(H)(CH₃)(PhR)], imino [HN?C(CH₃)(PhR)], thiocarbonyl [S?C(CH₃)(PhR)] and carbonyl [O?C(CH₃)(PhR)] ligands were performed, where R?NH₂, OCH₃, OH, CH₃, H, Cl, CN, and NO₂ is a substituent at the para‐position of a phenyl ring.The affinity of the pentaaqua nickel(II) complex for these ligands was analized and quantified in terms of interaction enthalpy (ΔH), Gibbs free energy (ΔG²⁹⁸), geometric and electronic parameters of the resultant octahedral complexes. The ΔH and ΔG²⁹⁸ results show that the ligand coordination strength increases in the following order: carbonyl < thiocarbonyl < imino < phosphoryl. This coordination strength order is also observed in the analysis of the metal‐ligand distances and charges on the ligand atom that interacts with the Ni(II) cation. The electronic character of the substituent R is the main parameter that affects the strength of the metal‐ligand coordination. Ligands containing electron‐donating groups (NH₂, OCH₃, OH) have more exothermic ΔH and ΔG²⁹⁸ than ligands with electron‐withdrawing groups (Cl, CN, NO₂). The metal‐ligand interaction decomposed by means of the energy decomposition analysis (EDA) method shows that the electronic character of the ligand modulates all the components of the metal‐ligand interaction. The absolute softness of the free ligands is correlated with the covalent contribution to the instantaneous interaction energy calculated using the EDA method. © 2013 Wiley Periodicals, Inc.     

Analysis of the intermolecular interaction between CH(3)OCH(3), CF(3)OCH(3), CF(3)OCF(3), and CH(4): high level ab initio calculations

The intermolecular interaction energies of the CH₃OCH₃? CH₄, CF₃OCH₃? CH₄, and CF₃OCF₃? CH₄ systems were calculated by ab initio molecular orbital method with the electron correlation correction at the second order Møller–Plesset perturbation (MP2) method. The interaction energies of 10 orientations of complexes were calculated for each system. The largest interaction energies calculated for the three systems are ?1.06, ?0.70, and ?0.80 kcal/mol, respectively. The inclusion of electron correlation increases the attraction significantly. It gains the attraction ?1.47, ?1.19, and ?1.27 kcal/mol, respectively. The dispersion interaction is found to be the major source of the attraction in these systems. In the CH₃OCH₃? CH₄ system, the electrostatic interaction (?0.34 kcal/mol) increases the attraction substantially, while the electrostatic energies in the other systems are not large. Fluorine substitution of the ether decreases the electrostatic interaction, and therefore, decreases the attraction. In addition the orientation dependence of the interaction energy is decreased by the substitution. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1472–1479, 2002     

Organic Phosphorus Compounds 56. The addition of hypophosphite esters to activated olefins,a new method for preparing 2-substituted ethyl phosphinates

The addition of methylhypophosphite, H₂P(O)OCH₃, to acrylic acid derivatives, CH₂?CHX (X ? CONH₂, CN, CO₂R), is described and the physical properties of three new 2-substituted ethylphosphinates are reported.     

Novel Copolymers of Alkyl and Alkoxy Ring‐Substituted Ethyl 2‐Cyano‐3‐phenyl‐2‐propenoates and Styrene

Abstract

Electrophilic trisubstituted ethylenes, ring‐substituted ethyl 2‐cyano‐3‐phenyl‐2‐propenoates, RC₆H₄CH?C(CN)CO₂C₂H₅ (where R is 2‐CH₃, 3‐CH₃, 4‐CH₃, 2‐OCH₃, 3‐OCH₃, and 4‐OCH₃) were prepared and copolymerized with styrene (ST). The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and ethyl cyanoacetate, and characterized by CHN analysis, IR, ¹H and ¹³C NMR. All the ethylenes were copolymerized with ST (M₁) in solution with radical initiation (AIBN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, ¹H and ¹³C NMR. The order of relative reactivity (1/r ₁) for the monomers is 3‐OCH₃ (0.88)?>?4‐CH₃ (0.71)?>?2‐OCH₃ (0.68)?>?3‐CH₃ (0.55)?>?2‐CH₃ (0.47)?>?4‐OCH₃ (0.40). Higher T _g of the copolymers in comparison with that of polystyrene indicates a decrease in chain mobility of the copolymer due to the high dipolar character of the TSE structural unit. Gravimetric analysis indicated that the copolymers decompose in the 257–287°C range.     

Multifunctional coupling agents for living cationic polymerization. IV. Synthesis of end-functionalized multiarmed poly(vinyl ethers) with multifunctional silyl enol ethers

Telechelic ( 8 ) and end-functionalized four-arm star polymers ( 9 ) were synthesized through the coupling reactions of end-functionalized living poly(isobutyl vinyl ether) ( 5; DP _n ～ 10) with the bi-and tetrafunctional silyl enol ethers, H_4-nC? [CH₂OC₆H₄C(OSiMe₃) = CH₂]_n ( 3: n = 2; 4: n = 4). The precursor polymers 5 were prepared by living cationic polymerization with functionalized initiators, CH₃CH(Cl)OCH₂CH₂X(6), in conjunction with zinc chloride in methylene chloride at ?15°C. The initiators 6 were obtained by the addition of hydrogen chloride gas to vinyl ethers bearing pendant functional groups X , including acetoxy [? OC(O)CH₃], styryl (? OCH₂C₆H₄-p-CH = CH₂), and methacryloyl [? OC(O)C(CH₃) = CH₂]. The coupling reactions with 3 and 4 in methylene chloride at ?15°C for 24 h afforded the end-functionalized multiarmed polymers ( 8 and 9 ) in high yield (>91%), where those with styryl or methacryloyl groups are new multifunctional macromonomers. © 1994 John Wiley & Sons, Inc.     

Preparation and properties of triorganostannylmethyl 2,3:5,6-di-O-isopropylidene-α-D-mannofuranosides; pesticidal and fungicidal activities of triphenylstannyl-carbohydrate derivates

The synthesis of trioganostannylmethyl 2,3:5,6-di-O-isopropylidene-α-D-mannofuranoside (compound 3, R*OCH₂SnR₂R′:R?R′?Me or Ph) from D-mannose is reported. The compound 3 (R?R′?Ph) is transmetallated by PhLi to compound 5, R*OCH₂Li, Which can be trapped by HgCl₂ [as (R*OCH₂)₂Hg] and by ketones, R³COMe [as compound 7, R*OCH₂CR³MeOH]. Two stereoisomers of this compound (7a, R³?Ph) were formed in a ratio of 40:60, indicating some asymmetric induction, arising from the chiral R* moiety. Reactions of compound 3, (R?R′?Ph), with I₂, HO₂CCF₃ and Cl₂PtCOD result in Ph–Sn bond cleavage and formation of compound 3 with R?Ph; R′?I, OCOCF₃ and Cl respectively. Reactions of compound 3 (R?R′?Me) with electrophiles can lead to cleavage of either of both types of C–Sn bonds present (e.g. by I₂, Br₂, Cl₂PtCOD or SnCl₄) or to attack at the C₅–C₆ protecting group with release of acetone (e.g. by CF₃CO₂H, SO₂ or CH₃COCl). Pesticidal and fungicidal activities of compound 3(R?R′?Ph) as well as of 1,2:5,6-di-O-isopropylidene-3-O(triphenylstannylmethyl)-α-D-glucofuranose (compound 2, R?Ph) and methyl 4, 6-O-benzylidene-2-deoxy-2-triphenylstannyl-α-D-altropyranoside (compound 1, R?Ph) are reported.     

The [CH5NO]+ ˙ potential energy surface: Distonic ions,lon-dipole complexes and hydrogen-bridged radical cations

By combining results from a variety of mass spectrometric techniques (metastable ion, collisional activation, collision-induced dissociative ionization, neutralization-reionization spectrometry, ²H, ¹³C and ¹⁸O isotopic labelling and appearance energy measurements) and high-level ab initio molecular orbital calculations, the potential energy surface of the [CH₅NO]^{+ ˙} system has been explored. The calculations show that at least nine stable isomers exist. These include the conventional species [CH₃ONH₂]^{+ ˙} and [HO? CH₂? NH₂]^{+ ˙}, the distonic ions [O? CH₂? NH₃]^{+ ˙}, [O? NH₂? CH₃]^{+ ˙}, [CH₂? O(H)? NH₂]^{+ ˙}, [HO? NH₂? CH₂]^{+ ˙}, and the ion-dipole complex CH₂?NH₂⁺ …? OH˙. Surprisingly the distonic ion [CH₂? O? NH₃]^{+ ˙} was found not to be a stable species but to dissociate spontaneously to CH₂?O + NH₃^{+ ˙}. The most stable isomer is the hydrogen-bridged radical cation [H? C?O …? H …? NH₃]^{+ ˙} which is best viewed as an immonium cation interacting with the formyl dipole. The related species [CH₂?O …? H …? NH₂]^{+ ˙}, in which an ammonium radical cation interacts with the formaldehyde dipole is also a very stable ion. It is generated by loss of CO from ionized methyl carbamate, H₂N? C(?O)? OCH₃ and the proposed mechanism involves a 1,4-H shift followed by intramolecular ‘dictation’ and CO extrusion. The [CH₂?O …? H …? NH₂]^{+ ˙} product ions fragment exothermically, but via a barrier, to NH₄^{+ ˙} HCO^…? and to H₃N? C(H)?O^{+ ˙} H˙. Metastable ions [CH₃ONH₂]^+…? dissociate, via a large barrier, to CH₂?O + NH₃⁺ + and to [CH₂NH₂]⁺ + OH˙ but not to CH₂?O^{+ ˙} + NH₃. The former reaction proceeds via a 1,3-H shift after which dissociation takes place immediately. Loss of OH˙ proceeds formally via a 1,2-CH₃ shift to produce excited [O? NH₂? CH₃]^{+ ˙}, which rearranges to excited [HO? NH₂? CH₂]^{+ ˙} via a 1,3-H shift after which dissociation follows.     

Trifluoroethylene Sultone: Structure and Chemistry

The gas phase structure of trifluoroethylene sultone, ( 1 ) (3,4,4-trifluoro-1,2-oxathietane-2,2-dioxide) was determined by gas electron diffraction, and the four-membered ring was found to be planar. The following ring parameters (r_a distances and ∠_α angles with 3σ uncertainties) were derived in the electron diffraction analysis: C? O = 1.41 Å (ass.), C? C = 1.541(18) Å, S? O = 1.652(5) Å, S? C = 1.822(8) Å, S? C? C = 86.2(15)°, C? C? O = 97.1(28)°, C? O? S = 97.5(21)°, and O? S? C = 79.1(8)°. New spectral data (IR, NMR) of 1 , its acyclic isomer FSO₂CFHC(O)F ( 2 ), and the related anhydride, FSO₂OSO₂CFHC(O)F ( 3 ), are reported. New esters containing the fluorosulfonyl function, FSO₂CFHC(O)OCH₂CF₃ ( 4 ), FSO₂CFHC(O)OCH₂CH = CH₂ ( 5 ), and (FSO₂CFHC(O)OCH₂CH? CH₂? )_n ( 6 ) have been prepared and characterized.     

Theoretical study of the effects of substitution,solvation, and structure on the interaction between nitriles and methanol

We report an investigation on intermolecular interactions in R? CN ··· H? OCH₃ (R = H, CH₃, F, Cl, NO₂, OH, SH, SCH₃, CHO, COCH₃, CH₂Cl, CH₂F, CH₂OH, CH₂COOH, CF₃, SCOCH₃, SCF₃, OCHF₂, CH₂CF₃, CH₂OCH₃, and CH₂CH₂OH) complexes using density functional theory. The calculations were conducted on B3LYP/6‐311++G** level of theory for optimization of geometries of complexes and monomers. An improper hydrogen bonding (HB) in the H₃CO? H ··· NC? R complexes was observed in that N atom of the nitriles functions acts as a proton acceptor. Furthermore, quantum theory of “Atoms in Molecules” (AIM) and natural bond orbital (NBO) method were applied to analyze H‐bond interactions in respective complexes. The electron density (ρ) and Laplacian (?²ρ) properties, estimated by atoms in molecules calculations, indicate that H ··· N bond possesses low ρ and positive ?²ρ values, which are in agreement with partially covalent character of the HBs, whereas O? H bonds have negative ?²ρ values. In addition, the weak intermolecular force due to dipole–dipole interaction (U) is also considered for analysis. The examination of HB in these complexes by quantum theory of NBO method fairly supports the ab initio results. Natural population analysis data, the electron density, and Laplacian properties, as well as, the ν(O? H) and γ(O? H) frequencies of complexes, calculated at the B3LYP/6‐311++G** level of theory, are used to evaluate the HB interactions. The calculated geometrical parameters and conformational analysis in water phase solution show that the H₃CO? H ··· NC? R complexes in water are more stable than that in gas phase. The obtained results demonstrated a strong influence of the R substituent on the properties of complexes. Numerous correlations between topological, geometrical, thermodynamic properties, and energetic parameters were also found. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

Solvent effects on the polymerization of multi-armed vinyl biphenyl derivatives containing pendant oligo(oxyethylene)cyclotriphosphazenes

Polymerization of vinyl biphenyl derivatives containing a pendant oligo(oxyethylene)cyclotriphosphazene (VBMEP, ? (OCH₂CH₂)nOCH₃, n = 1; VBDEP, n = 2; VBTEP, n = 3) was carried out in various solvents. The conversions of these monomers increased with increasing β values, solvent hydrogen bond acceptor abilities, indicating that the hydrogen bond formation is the most important factor in the polymerization. ¹³CNMR study showed that the reactivity of the monomer is influenced by the hydrogen bond interaction. In ethanol, the kinetic orders of monomer and initiator concentrations for the polymerization of VBDEP were different from those in 1,2-dichloroethane (DCE), which suggest the predominant occurrence of primary radical termination. The intrinsic viscosity of poly(VBDEP) with M?_n = 22 000 in DCE was two times higher than that in ethanol, and plots of intrinsic viscosity versus conversion of VBDEP gave a straight line. The results suggest that the polymer chains in ethanol are in a coiled conformation, whereas in DCE they are in a relatively extended structure, and that the propagation is affected by the conformational change. These behaviors originated from the hydrogen bond formation between polymers and solvents are discussed. The copolymerization of styrene with multiarmed monomers and the properties of polycascade polymers obtained are also described. © 1993 John Wiley & Sons, Inc.     

Conformational properties of polar polymers. II. Poly(vinylidene chloride)

A recently developed polarization model for representing polar bond effects in conformational energy calculations is applied to poly(vinylidene chloride) (PVDC). The geometries and conformational energies of a number of conformers of 2,2,4,4,6,6-hexachloroheptane were calculated. The geometries were found to be similar to the hydrocarbon analog polyisobutylene (PIB) in that steric crowding results in the usual T, G, G′ states being split into + or ? distortions of the torsional angles away from the traditional values. Only distortions of the same sign occur in the same pair of bonds interior to CCl₂ groups. Distortions of G states towards eclipsed were found to be much more stable than those away. The interior skeletal valence angle is also distorted to an unusually large value, ca. 121°. The calculated dipole moments were used to infer a group moment for CCl₂ of 1.56 D. The calculated conformational energies were fitted by linear combinations of interaction parameters representing the stabilities of G₊, G_? bonds (relative to T₊, T_?) and the interactions between bonds across intervening CCl₂ groups. These parameters were used in statistical mechanical calculations of the characteristic and dipole-moment ratios. In order to make comparison with experiment, the dipole-moment/repeat unit of a 90% (by weight) PVDC copolymer with PVC was measured and found to be 1.42 ± 0.05 D. From this, the dipole-moment ratio for PVDC homopolymer is inferred to be ca. 0.8. The characteristic and dipole-moment ratios calculated from the interaction parameter set were somewhat too high but adjustment of the gauche energies downward brings the calculated ratios into agreement with experiment. The same statistical model along with energy parameters previously calculated also gives agreement with experiment for the characteristic ratio of PIB. The calculated geometries are in agreement with the conformation in the crystal being ? (T₊G′₊T_?G_?)? .     

Synthesis,Characterization, and Structures of α-Substituted Selenenyl-Acetophenones

Abstract

A series of α-substituted selenenyl acetophenone derivatives of the types, [PhC(OCH₂CH₂O)CH₂Se]₂, [PhC(OCH₂CH₂O)CH₂SeR], (PhCOCH₂Se)_2, and [PhCOCH₂SeR] have been prepared. These compounds have been characterized by elemental analyses, IR and NMR (¹H, ¹³C, ⁷⁷Se) spectroscopy. The compounds, [PhC(OCH₂CH₂)CH₂Se]₂ and (PhCOCH₂Se)₂ have been structurally characterized by single crystal X-ray diffraction analyses. The former shows intra-molecular Se‐?‐?‐O interaction, while the latter exhibits inter-molecular nonbonding Se‐?‐?‐O interaction.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]