2-(Phenylthio)ethyl chloride specifically deuterated alpha to the sulfur atom (i.e. 2-Cl) was employed to study the mechanism of displacement of chloride ion by iodide ion in dry acetone solution. Experimental evidence including rate studies has been accumulated that allows the conclusion to be drawn that iodide ion displaces chloride ion from 2-Cl by a classical S(N)2 mechanism to give 2-I. Under the reaction conditions, however, 2-I is reactive toward anchimerically-assisted ionization which leads to product with the deuterium label scrambled. Reaction of 2-Cl with bromide ion follows a similar course. Our displacement reactions of halide ions by halide ions showed the expected nucleophilicity order of Cl- > Br- > I- and the normal leaving group order of I- > Br- > Cl-. An interesting counterion effect was noted with iodides displacing chloride ion. While potassium iodide in acetone converted 2-Cl to the mixture of iodides 2-I and 3-I, tetrabutylammonium iodide caused conversion but the products reverted completely back to the label-scrambled chlorides. The difference in these results is probably because of differences in the thermodynamics of the two systems.

Polydiacetylenes are a very promising class of polymers for both photonic and electronic applications because of their highly conjugated structures. For these applications, high-quality thin polydiacetylene films are required. We have discovered a novel technique for obtaining such films of a polydiacetylene derivative of 2-methyl-4-nitroaniline using photodeposition from monomer solutions onto UV transparent substrates. This heretofore unreported process yields amorphous polydiacetylene films with thicknesses on the order of 1 mu m that have optical quality superior to that of films grown by standard crystal growth techniques. Furthermore, these films exhibit good third-order nonlinear optical susceptibilities; degenerate four-wave mixing experiments give chi((3)) values on the order of 10(-8)-10(-7) esu. We have conducted masking experiments which demonstrate that photodeposition occurs only where the substrate is directly irradiated, clearly indicating that the reaction occurs at the surface. Additionally, we have also been able to carry out photodeposition using lasers to form thin polymer circuits. In this work, we discuss the photodeposition of polydiacetylene thin films from solution, perform chemical characterization of these films, investigate the role of the substrate, speculate on the mechanism of the reaction, and make a preliminary determination of the third-order optical nonlinearity of the films. This simple, straightforward technique may ultimately make feasible the production of polydiacetylene thin films for technological applications.

A novel technique has been developed for preparing thin amorphous films of a polydiacetylene derivative of 2-methyl-4-nitroaniline (MNA) using photodeposition from monomer solutions. This heretofore unknown process yields films that possess very high optical quality and exhibit large third-order nonlinear optical susceptibilities (10(-8)-10(-7) esu). Photodeposition can also be carried out using lasers to form thin optical circuits. This could eventually make the application of polydiacetylene thin films for nonlinear optical devices such as waveguides and integrated optics more commercially feasible.

We have achieved the synthesis and isolation, without substantial label scrambling, of 2-(phenylthio)-ethyl-2,2-d2 chloride (2-Cl), a compound useful in modeling reactions of mustard and other highly reactive beta-thioethyl chlorides. 2-Cl undergoes slow label scrambling upon dissolution in hot, dry acetonitrile or acetone. Rates of scrambling of the deuterium label in 2-Cl have been measured by following proton NMR changes. Our present work clearly demonstrates that cyclic sulfonium ions are involved in these scrambling reactions. In anhydrous or aqueous acetone, thiourea traps the sulfonium ion intermediate to give stable, label-scrambled thiouronium salts. In anhydrous acetone, in competition with formation of the thiouronium salts, chloride return occurs giving 2-Cl and its label-scrambled isomer, 2-(phenylthio)ethyl-1,1-d2 Chloride (1-Cl). However, no chloride return is observed in 60% aqueous acetone. Mechanistic implications of these results are presented.

A novel diacetylene derivative of 2-methyl-4-nitroaniline (MNA), a well-known material for second-harmonic generation (SHG), is synthesized. This monomer (diacetylene methylnitroaniline, DAMNA) is characterized by means of the Kurtz technique at 1064 nm and is found to have an SHG powder efficiency 62.5 % that of MNA itself. Thin crystalline films of DAMNA are grown onto quartz, Teflon, and Kapton substrates by means of vapor deposition in vacuum. These films are then polymerized in the solid state by exposure to long-wavelength UV radiation to give crystalline polydiacetylene thin films (PDAMNA). The films are next characterized for SHG, using an unpolymerized DAMNA film as a reference. Interestingly, films grown onto Teflon exhibit greater orientation and significantly greater SHG than those grown onto quartz and Kapton. This result is promising in that it demonstrates the potential of PDAMNA as both a crystalline and polymeric material for SHG applications, in which highly oriented thin films are desired. Computational modeling (using AM1) is also carried out on DAMNA and is compared to the experimental results.

In the present work two diacetylene derivatives of pyrrole (compounds 1 and 2), which are predicted by semiempirical AM1 calculations to have very different properties, are synthesized; the polymerizability of these diacetylenes in the solid state is determined; and the results are compared to the computer predictions. Diacetylene 1 is novel in that the monomer is a liquid at room temperature; this may allow for the possibility of polymerization in the liquid state as well as the solid state. Thin poly(diacetylene) film are obtained from compound 1 by growing films of the monomer using vapor deposition and polymerizing with UV light; these films are then characterized. Interestingly, while the poly(diacetylene) from 1 does not possess good nonlinear optical properties, the monomer exhibits very good third-order nonlinear optical effects (e.g., phase conjugation) in solution. Dilute acetone solutions of the monomer 1 give intensity-dependent refractive indices (n2) on the order of 10(-6) esu (chi(3) values on the order of 10(-7) esu); these are 10(6) times better than for CS2.

AM1 and PM3 semiempirical SCF-MO methods have been used to calculate structures and properties of model polysilanes. Bond lengths and molecular orbital energies of poly(hydrosilanes) calculated by both methods are in good agreement with ab initio results, but bond angles deviate slightly. Our studies of molecular geometry and electronic properties of polysilane models show similar behavior for the AM1 and PM3 methods in most cases, but the PM3 method appears to be superior in predicting bandgaps. The PM3 method predicts that the anti conformer of Si4(CH3)10 lies almost-equal-to 1.0 kcal/mol lower in energy than the gauche conformer. Studies evaluating polysilanes bearing substituent groups with different steric requirements and electronic properties (Me, Et, F, Cl, and OCH3) were instructive. Compared to the unsubstituted model, all of the substituted polysilanes have larger Si-Si bond angles, in agreement with experiment. Our calculations suggest that substituents may have a significant effect on Si-Si-Si bond angles pushing them to well above the 120-degrees value estimated for the hexyl derivative from X-ray data. The effect of substitution on electronic properties is predicted to be complicated. For calculation of structure and properties of polysilane models overall, the AM1 and PM3 methods are judged to provide excellent agreement with experimental data and ab initio methods.

The electronic properties of some model poly(diacetylenes) were investigated by using AM1 and, to a limited extent, MNDO and PM3 semiempirical SCF-MO methods. The capped-bond option allowed for simulation of polymer structures but the option has limitations when computing electronic properties of conjugated polymers. With optimized geometries, AM1-computed structures for poly(diacetylene) models favor the enyne structure. The chemical and electronic effects of substituents on the structure of the polymer backbone were investigated, and the Koopman ionization potential and bandgap were computed and discussed. The changes in HOMO and LUMO energies as a function of nonplanarity along the backbone were also calculated. The bandgaps of some diacetylene monomers and several oligomers were computed for comparison with experimental values of diacetylene monomers and polymers. Finally, some AM1 calculations are included showing variations in geometry, atomic charge, and bandgap with chain length in a series of oligomeric diacetylenes.

Studies have been carried out with the tosylate of the monomethyl ether of polyethylene glycol (MeO–PEG–OTs) and with low molecular weight models to assess whether the neighboring oxygen at position 3 or 6 provides the driving force for hydrolytic cleavage of these activated derivatives. Our results reveal that MeO–PEG–OTs undergoes hydrolysis by competitive pathways. Water directly displaces the tosylate group to give the original PEG alcohol and the oxygen at position 6 nucleophilically displaces the tosylate group to give a cyclic oxonium ion as an intermediate. This intermediate can react by three pathways. First, it can lead to the production of the original PEG alcohol by attack of water on a ring carbon; second, dioxane and a lower molecular weight PEG alcohol is produced by water attack at the nonring carbon next to the charged oxygen; and third dioxane can be displaced by the oxygen atom at position 6 in the chain.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEvaluation of nonlinear ethanol-trifluoroethanol correlations for mustard chlorohydrin and other anchimerically assisted alkyl substratesSamuel P. McManus, M. Reza Sedaghat-Herati, Rashid M. Karaman, Nouri Neamati-Mazraeh, Scott M. Cowell, and J. Milton HarrisCite this: J. Org. Chem. 1989, 54, 8, 1911–1918Publication Date (Print):April 1, 1989Publication History Published online1 May 2002Published inissue 1 April 1989https://pubs.acs.org/doi/10.1021/jo00269a030https://doi.org/10.1021/jo00269a030research-articleACS PublicationsRequest reuse permissionsArticle Views71Altmetric-Citations8LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ChemInformVolume 20, Issue 6 Preparative Organic Chemistry ChemInform Abstract: Use of the Broensted Relationship to Detect a Mechanistic Shift for Reaction of 2-(Methylthio)ethyl Chloride with Thiophenoxide Anions. J. M. HARRIS, J. M. HARRIS Dep. Chem., Univ. Ala., Huntsville, AL 35899, USASearch for more papers by this authorM. R. SEDAGHAT-HERATI, M. R. SEDAGHAT-HERATI Dep. Chem., Univ. Ala., Huntsville, AL 35899, USASearch for more papers by this authorS. P. MCMANUS, S. P. MCMANUS Dep. Chem., Univ. Ala., Huntsville, AL 35899, USASearch for more papers by this author J. M. HARRIS, J. M. HARRIS Dep. Chem., Univ. Ala., Huntsville, AL 35899, USASearch for more papers by this authorM. R. SEDAGHAT-HERATI, M. R. SEDAGHAT-HERATI Dep. Chem., Univ. Ala., Huntsville, AL 35899, USASearch for more papers by this authorS. P. MCMANUS, S. P. MCMANUS Dep. Chem., Univ. Ala., Huntsville, AL 35899, USASearch for more papers by this author First published: February 7, 1989 https://doi.org/10.1002/chin.198906079AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue6February 7, 1989 RelatedInformation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelectivity in the solvolysis in binary solvents of 1-adamantyl derivatives bearing leaving groups that depart as neutral moleculesSamuel P. McManus, Terry Crutcher, R. Wendel Naumann, Kerry L. Tate, Steven E. Zutaut, Alan R. Katritzky, and Dennis N. KevillCite this: J. Org. Chem. 1988, 53, 18, 4401–4403Publication Date (Print):September 1, 1988Publication History Published online1 May 2002Published inissue 1 September 1988https://doi.org/10.1021/jo00253a041Request reuse permissionsArticle Views45Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (410 KB) Get e-Alertsclose Get e-Alerts

2-(Methylthio)ethyl tosylate undergoes facile dimerization. Previous OTs/Cl rate ratios were based on reaction of the tosylate dimer. New ratios, which are still low, are reported.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCompetitive RO-6 neighboring group participation and solvent-assisted displacement with 2-(2-methoxyethoxy)ethyl tosylateSamuel P. McManus, Rashid M. Karaman, Bruce A. Hovanes, M. Steven Paley, and J. Milton HarrisCite this: J. Org. Chem. 1988, 53, 3, 681–683Publication Date (Print):February 1, 1988Publication History Published online1 May 2002Published inissue 1 February 1988https://pubs.acs.org/doi/10.1021/jo00238a037https://doi.org/10.1021/jo00238a037research-articleACS PublicationsRequest reuse permissionsArticle Views96Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSN2 Displacement on 2-(alkylthio)ethyl derivativesM. R. Sedaghat-Herati, Samuel P. McManus, and J. Milton HarrisCite this: J. Org. Chem. 1988, 53, 11, 2539–2543Publication Date (Print):May 1, 1988Publication History Published online1 May 2002Published inissue 1 May 1988https://pubs.acs.org/doi/10.1021/jo00246a025https://doi.org/10.1021/jo00246a025research-articleACS PublicationsRequest reuse permissionsArticle Views312Altmetric-Citations23LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts