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Nucleophilic reactivity constants toward methyl iodide and trans-dichlorodi(pyridine)platinum(II)
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNucleophilic reactivity constants toward methyl iodide and trans-dichlorodi(pyridine)platinum(II)Ralph G. Pearson, Harold R. Sobel, and Jon SongstadCite this: J. Am. Chem. Soc. 1968, 90, 2, 319–326Publication Date (Print):January 1, 1968Publication History Published online1 May 2002Published inissue 1 January 1968https://pubs.acs.org/doi/10.1021/ja01004a021https://doi.org/10.1021/ja01004a021research-articleACS PublicationsRequest reuse permissionsArticle Views2288Altmetric-Citations403LEARN 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
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“Nitrite is a weak nucleophile [40], and in aqueous conditions and at biological pH, it will not easily react with electrophiles, also because of the solvation effects of water molecules.”
From On the chemical biology of the nitrite/sulfide interaction (2015) · cites this paper as [40]
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Vecht, J. R. V. D., Dirks, R. J., Steinberg, H., et al. (1977) · Recueil des Travaux Chimiques des Pays-Bas · doi:10.1002/recl.19770961206 · Cited by 15
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Bentley, T. W. (2010) · Journal of Physical Organic Chemistry · doi:10.1002/poc.1670 · Cited by 14
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Kemmitt, R. D. W., & Russell, D. R. (1982) · Elsevier eBooks · doi:10.1016/b978-008046518-0.00063-5 · Cited by 12
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Kice, J. L. (1972) · Progress in inorganic chemistry · doi:10.1002/9780470166185.ch4 · Cited by 12
Spange, S., Fandrei, D., Simon, F., et al. (1994) · Colloid & Polymer Science · doi:10.1007/bf00653314 · Cited by 12
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Maturano, M., Bongibault, V., Willson, M., Klaébé, A., & Fournier, D. D. (1997) · Tetrahedron · doi:10.1016/s0040-4020(97)10176-4 · Cited by 9
Jacobi, A., Hüttner, G., Winterhalter, U., & Cunskis, S. (1998) · European Journal of Inorganic Chemistry · doi:10.1002/(sici)1099-0682(199806)1998:6 · Cited by 12
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Odiaka, T. I. (1989) · Inorganica Chimica Acta · doi:10.1016/s0020-1693(00)83215-6 · Cited by 11
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Lin, P., Bentz, G., & STAMM, H. (1993) · Journal für praktische Chemie · doi:10.1002/prac.19933350105 · Cited by 10
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Metadata
- Authors
- Pearson, R. G., Sobel, H. R., & Songstad, J.
- Venue
- Journal of the American Chemical Society
- Publisher
- American Chemical Society (ACS)
- Published
- 1968-01
- Volume
- 90
- Issue
- 2
- Pages
- 319-326
- ISSN
- 0002-7863 (ISSN-L)
- 1520-5126
- OpenAlex
- W2036857388
- Semantic Scholar
- 613127c88fc48462094c40dab33dd31235e754c5
- Cited by
- 455
- References
- 0
- Citations by year
- 2026: 2 · 2025: 7 · 2024: 3 · 2023: 8 · 2022: 7 · 2021: 7 · 2020: 1 · 2019: 7 · 2018: 7 · 2017: 5 · 2016: 5 · 2015: 8 · 2014: 19 · 2013: 10 · 2012: 13
- FWCI
- 8.21
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Journal of the American Chemical Society (publishedVersion)
- Topics
- Physical Sciences › Chemistry › Organic Chemistry › Physical Organic Chemistry and Reaction Kinetics
- Physical Sciences › Chemistry › Inorganic Chemistry › Inorganic and Organometallic Chemistry
- Health Sciences › Medicine › Oncology › Metal complexes synthesis and properties
- Keywords
- methyl iodide, nucleophilicity, nucleophilic substitution, platinum(II) complexes, pyridine ligands
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