Chemischer InformationsdienstVolume 17, Issue 26 Physical Organic Chemistry ChemInform Abstract: Vibrational Spectra and Assignments of MeMn(CO)5 and MeRe(CO)5 Species, Energy-Factored and A1 Force Fields, and a Further Effect of Free Internal Rotation G. P. MCQUILLAN, G. P. MCQUILLANSearch for more papers by this authorD. C. MCKEAN, D. C. MCKEANSearch for more papers by this authorC. LONG, C. LONGSearch for more papers by this authorA. R. MORRISSON, A. R. MORRISSONSearch for more papers by this authorI. TORTO, I. TORTOSearch for more papers by this author G. P. MCQUILLAN, G. P. MCQUILLANSearch for more papers by this authorD. C. MCKEAN, D. C. MCKEANSearch for more papers by this authorC. LONG, C. LONGSearch for more papers by this authorA. R. MORRISSON, A. R. MORRISSONSearch for more papers by this authorI. TORTO, I. TORTOSearch for more papers by this author First published: July 1, 1986 https://doi.org/10.1002/chin.198626040AboutPDF 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. Volume17, Issue26July 1, 1986 RelatedInformation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVibrational spectra and assignments of MeMn(CO)5 and MeRe(CO)5 species, energy-factored and A1 force fields, and a further effect of free internal rotationG. P. McQuillan, D. C. McKean, C. Long, A. R. Morrisson, and I. TortoCite this: J. Am. Chem. Soc. 1986, 108, 5, 863–871Publication Date (Print):March 1, 1986Publication History Published online1 May 2002Published inissue 1 March 1986https://doi.org/10.1021/ja00265a002RIGHTS & PERMISSIONSArticle Views153Altmetric-Citations25LEARN 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 (1 MB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Recent and current work on spectra in the CH and CD stretching regions of methyl-metal compounds is reviewed. Free internal rotation with CH force constant variation is found in MMe3 (M  Ga, Tl) and MMe(CO)5 (M  Mn, Re) compounds, studied in the gas phase. From solution measurements, no such rotation occurs in CpMMe(CO)3 (M  Cr,Mo,W) and Cp2MMe2 (M  Ti,Zr,Hf), in most of which each methyl group contains two types of CH bond. In each d-subgroup, νisCH decreases with increasing atomic number, while δsCH3 increases. The reverse occurs from Ga to Tl. roCH values are predicted. There is evidence for the breakdown of the νisCH/∠HCH correlation, especially in MeTiCl3 where several features point to an unusual structure of the methyl group.

n-Butane-d9 was synthesized with the hydrogen atom located in one of the methyl groupings. Both CH stretches of the trans conformer and two of the three CH stretches of the gauche conformer were assigned to transitions observed in the gas phase infrared spectrum, using the harmonic rigid rotor approximation. The simulation lends support to the more recent literature values of the trans—gauche relative populations. The assignments agree with those obtained by other authors using different techniques, and, when compared to νisCH values in propane, lead to γ substitution effects of methyl which are very small, except perhaps on the op*g (out-of-plane gauche) bond, where steric interaction is likely.

'Isolated' methyl CH stretching frequencies, ν(CHis), are reported for [M(CHD2)(η5-C5H5)(CO)3](M = Cr, Mo, or W) and are used to predict CH bond lengths, bond-dissociation energies, and mean HCH angles. The methyl groups are subject to appreciable internal rotation energy barriers and each contain two different types of CH bond, with non-equivalent orientations in the molecule and with significantly different bond lengths and strengths. The CH bond strengths decrease in the order Cr > Mo > W, reflecting a corresponding increase in metal–carbon bond strength estimated to be of the order of 55–70% from Cr to W. The methyl groups in [Cr(CHD2)(η5-C5H5)(CO)3] and [Cr(CD3)(η5-C5H5)(CO)3] are affected by extensive H/D exchange, probably with the 1,2-dimethoxyethane solvent used in the preparative reaction.

Isolated SnH stretching frequencies have been obtained from i.r. spectra of SnHD3, MeSnHD2, EtSnHD2, Me2SnHD, Et2SnHD, Me3SnH and Et3SnH. 2νisSnH frequencies are also reported for Me2SnHD and Me3SnH. Two bands separated by 3.6 cm−1 in the case of EtSnHD2 represent the differing β effects of the methyl group. A close comparison of the SnH data with earlier GeH ones indicates that the conformers predominating in both Et2SnH2 and Et3SnH have all methyl groups gauche to the SnH bonds, in contrast to the situation in analogous GeH compounds.

Chemischer InformationsdienstVolume 16, Issue 12 Physical Organic Chemistry ChemInform Abstract: INFRARED SPECTRA OF METHYLMANGANESE PENTACARBONYL AND METHYLRHENIUM PENTACARBONYL SPECIES: METHYL GROUP GEOMETRY AND THE EFFECTS OF INTERNAL ROTATION C. LONG, C. LONGSearch for more papers by this authorA. R. MORRISSON, A. R. MORRISSONSearch for more papers by this authorD. C. MCKEAN, D. C. MCKEANSearch for more papers by this authorG. P. MCQUILLAN, G. P. MCQUILLANSearch for more papers by this author C. LONG, C. LONGSearch for more papers by this authorA. R. MORRISSON, A. R. MORRISSONSearch for more papers by this authorD. C. MCKEAN, D. C. MCKEANSearch for more papers by this authorG. P. MCQUILLAN, G. P. MCQUILLANSearch for more papers by this author First published: March 26, 1985 https://doi.org/10.1002/chin.198512049AboutPDF 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. Volume16, Issue12March 26, 1985 RelatedInformation

Infrared spectra in the SiH stretching region are reported for SiH3CH2Cl, SiHD2CH2Cl, SiH3Et, SiHD2Et, SiHDEtMe, SiHDEt2, SiHEt3, (SiH3)2CH2, (SiHD2)(SiD3)CH2, SiH3CH=CH2 and SiHD2CH=CH2 in the gas phase, and for SiH3CH2Cl, SiH3Et, SiHEt3 and SiHMe3 in hydrocarbon solvents. The presence of several types of SiH bond in the gas phase is diagnosed in all cases except those of disilyl methane and vinyl silane. These reflect the differing β effects of halogen and methyl groups. For the alkyl silanes, νSiH = 2125.8 + 41.0 Σσ*, for selected frequencies.

Infrared and Raman spectra have been obtained from 11 isotopomers of cis and trans but-2-enes in various phases (c- and t-CH3CHCHCH3, CH3CHCDCH3, CD3CHCHCD3, CD3CHCDCD3, CD3CDCDCD3; c-CH3CDCDCH3). Nearly all the fundamentals are securely assigned. Isolated CH stretching frequencies νisCH are observed or deduced from the spectra and used to predict CH bond lengths and dissociation energies. The olefinic CH and methyl CHs bonds are stronger in the cis compound than those in the trans, in keeping with substituent effects previously observed in propene, and with molecular mechanics predictions. Comparison of νisCH values with local mode fifth overtone spectra for cis-CH3CHCHCH3 indicates that the part of the latter associated with the CHa bond cannot be readily interpreted.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfrared spectra of methylmanganese pentacarbonyl and methylrhenium pentacarbonyl species: methyl group geometry and the effects of internal rotationC. Long, A. R. Morrisson, D. C. McKean, and G. P. McQuillanCite this: J. Am. Chem. Soc. 1984, 106, 24, 7418–7427Publication Date (Print):November 1, 1984Publication History Published online1 May 2002Published inissue 1 November 1984https://pubs.acs.org/doi/10.1021/ja00336a021https://doi.org/10.1021/ja00336a021research-articleACS PublicationsRequest reuse permissionsArticle Views126Altmetric-Citations20LEARN 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

SiH stretching overtones have been studied in the infrared spectrum up to Δν = 5 for SiH4, (CH3)2SiH2 and (CH3) 3SiH and for Δν = 3 in CH3SiH3. The data for (CH3)2SiH2 and (CH33SiH necessitate a cubic term in the term value equation whose presence can explain the existing discordance between spectroscopically predicted and experimental values of Do(Si-H) in Methyl silanes. Earlier “local-mode” model predictions for the spectrum Of SiH4 are accurate with respect to frequencies, but not to intensity.

Infrared spectra have been recorded for CHD2GeH3 and CH3GeHD2 at a resolution of 0.06 cm−1. The K structure of four perpendicular-type bands of the former, and one of the latter species, were analysed to give A0 − B0 = 1.2252 (8) and 1.2511 (18) cm−1 respectively. These data are used in conjunction with earlier microwave results to obtain a new ground state geometry for methyl germane: r0CH = 1.0921, r0GeH = 1.5285, r0GeC = 1.9490 Å, ∠HCH = 108.84o, ∠HGeH = 108.78o, whose r0 CH and ∠HCH values are in good agreement with those predicted from “isolated” CH stretching frequencies. The geometries of Me2GeH2, Me3GeH, EtGeH3, CH3GeH2F, CH3GeH2Cl and GeH3CH2Cl are examined critically. The correlation between νisGeH and r0 GeH is improved by a revised r0 GeH for Me3GeH, but CH3GeH2Cl constitutes a further anomaly. Trends in GeC and GeX distances are similar to those of CC and CX.

La constante de force de la vibration CH varie avec l'angle de rotation interne d'un groupe methyle. La barriere de rotation est probablement inferieure a 10 cm −1 . Les principales longueurs de liaison CH sont de 1,095 (pour Mn) et 1,098 (pour Re) avec une variation de 0,004 a 0,006 A lors de la rotation

Infrared gas phase spectra in the SiH and GeH stretching regions are reported for cyclopropyl-SiH3, -SiHD2, -GeHD2, cyclopentyl-SiHD2 and -GeHD2. In each case two bands are seen which indicate the presence of stronger MHa and weaker MHs bonds,the difference in strength being about 5 cm−1. The effect appears to be similar to that found earlier in ethyl and isopropyl germanes and silanes. Values of σ* deduced from νis MH are: cyclopentyl −0.25 (Si), −0.23 (Ge); cyclopropyl −0.14 (Si), −0.08 (Ge), which reflect the decreased +I effect of the cyclopropyl group.

Chemischer InformationsdienstVolume 14, Issue 30 Physical Organic Chemistry ChemInform Abstract: VIBRATIONAL SPECTRA, ISOLATED C-H STRETCHING FREQUENCIES AND C-H BOND LENGTHS IN CH3OCH2X COMPOUNDS (X = F, CL, BR, I) D. C. MCKEAN, Search for more papers by this authorI. TORTO, Search for more papers by this authorA. R. MORRISSON, Search for more papers by this author D. C. MCKEAN, Search for more papers by this authorI. TORTO, Search for more papers by this authorA. R. MORRISSON, Search for more papers by this author First published: July 26, 1983 https://doi.org/10.1002/chin.198330046AboutPDF 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 onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume14, Issue30July 26, 1983 RelatedInformation

Infrared and Raman spectra are reported for CH3OCH2X, CHD2OCD2X, CD3OCHDX (XF, Cl, Br, I) and for CH3OCD2Cl and CD3OCH2Cl, in various phases. νCHis values are obtained which enable CH bond lengths and dissociation energies to be predicted. The changes in bond lengths from Me2O to MeOCH2X and from MeOCH2F to MeOCH2Cl are in good agreement with those calculated ab initio and in radical disagreement with microwave-based values. The effect of halogen is to strengthen all the CH bonds present, especially that lying parallel to the CX one.

Isolated GeH stretching frequencies are reported or derived from earlier work for 51 substituted germanes in the gas phase, the substituents including Me, Et, i-Pr, CF3, Ph, CN, C2H and X = F, Cl, Br, I. In a number of cases, very small positive stretch-stretch interaction force constants are obtained which reflect the virtual decoupling of bond stretching motions in GeH3 or GeH2 groups where the bonds differ but slightly in strength. This may be described as ‘local mode’ behaviour, in the fundamental region. β effects of Me, X and lone pairs of electrons are found which produce conformational variations in νisGeH comparable with those found in carbon analogues. These may be used inter alia to study conformer abundancies. Solid state spectra of GeH3NCO and GeH3NCS suggest that both of these have non-linear skeletons in this phase.

ADVERTISEMENT RETURN TO ISSUEArticleNEXTIsolated MH stretching frequencies, anharmonicities, and dissociation energies in silanes, germanes, phosphines, and arsinesD. C. McKean, I. Torto, and A. R. MorrissonCite this: J. Phys. Chem. 1982, 86, 3, 307–309Publication Date (Print):February 1, 1982Publication History Published online1 May 2002Published inissue 1 February 1982https://pubs.acs.org/doi/10.1021/j100392a001https://doi.org/10.1021/j100392a001research-articleACS PublicationsRequest reuse permissionsArticle Views105Altmetric-Citations54LEARN 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 options Get e-Alerts

IR spectra of the species GeHD2CH2F and GeHD2CH2Cl are reported which show two bands each, assigned to the solitary GeH bond either gauche or trans to the halogen atom, the splittings being 17 cm−1 (F) and 25.5 cm−1 (Cl), respectively. Similar pairs of bands are identified as due to GeHD2CH2Br, SiHD2CH2Cl and SiHD2CH2Br in earlier spectra.