{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,23]],"date-time":"2025-10-23T16:31:45Z","timestamp":1761237105974,"version":"build-2065373602"},"reference-count":37,"publisher":"Wiley","issue":"16","license":[{"start":{"date-parts":[[2004,7,5]],"date-time":"2004-07-05T00:00:00Z","timestamp":1088985600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Chemistry A European J"],"published-print":{"date-parts":[[2004,8,20]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>EPR spectra show that one\u2010electron reduction of bis(3\u2010phenyl\u20106,6\u2010(trimethylsilyl)phosphinine\u20102\u2010yl)dimethylsilane (<jats:bold>1<\/jats:bold>) on an alkali mirror leads to a radical anion that is localized on a single phosphinine ring, whereas the radical anion formed from the same reaction in the presence of cryptand or from an electron transfer with sodium naphthalenide is delocalized on the two phosphinine rings. Density functional theory (DFT) calculations show that in the last species the unpaired electron is mainly confined in a loose P\uf8ffP bond (3.479 \u00c5), which results from the overlap of two phosphorus p orbitals. In contrast, as attested by X\u2010ray spectroscopy, the P\uf8ffP distance in neutral <jats:bold>1<\/jats:bold> is large (5.8 \u00c5). As shown by crystal structure analysis, addition of a second electron leads to the formation of a classical P\uf8ffP single bond (P\uf8ffP 2.389 \u00c5). Spectral modifications induced by the presence of cryptand or by a change in the reaction temperature are consistent with the formation of a tight ion pair that stabilizes the radical structure localized on a single phosphinine ring. It is suggested that the structure of this pair hinders internal rotation around the C\uf8ffSi bonds and prevents <jats:bold>1<\/jats:bold> from adopting a conformation that shortens the intramolecular P\uf8ffP distance. The ability of the phosphinine radical anion to reversibly form weak P\uf8ffP bonds with neutral phosphinines in the absence of steric hindrance is confirmed by EPR spectra obtained for 2,6\u2010bis(trimethylsilyl)\u20103\u2010phenylphosphinine (<jats:bold>2<\/jats:bold>). Moreover, as shown by NMR spectroscopy, in this system, which contains only one phosphinine ring, further reduction leads to an intermolecular reaction with the formation of a classical P\uf8ffP bond.<\/jats:p>","DOI":"10.1002\/chem.200400073","type":"journal-article","created":{"date-parts":[[2004,7,5]],"date-time":"2004-07-05T14:36:28Z","timestamp":1089038188000},"page":"4080-4090","source":"Crossref","is-referenced-by-count":27,"title":["Effect of Conformational Changes on a One\u2010Electron Reduction Process: Evidence of a One\u2010Electron P\uf8ffP Bond Formation in a Bis(phosphinine)"],"prefix":"10.1002","volume":"10","author":[{"given":"Sylvie","family":"Choua","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cosmina","family":"Dutan","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Laurent","family":"Cataldo","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Th\u00e9o","family":"Berclaz","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michel","family":"Geoffroy","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicolas","family":"M\u00e9zailles","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Audrey","family":"Moores","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Louis","family":"Ricard","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pascal","family":"Le Floch","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2004,8,12]]},"reference":[{"key":"e_1_2_7_1_2","unstructured":"\u00a0"},{"volume-title":"Electron Transfer and Radical Processes in Transition\u2010Metal Chemistry","year":"1995","author":"Astruc D.","key":"e_1_2_7_2_2"},{"volume-title":"Organic Ion Radicals","year":"2003","author":"Todres Z. V.","key":"e_1_2_7_3_2"},{"key":"e_1_2_7_4_2","unstructured":"\u00a0"},{"key":"e_1_2_7_5_2","doi-asserted-by":"publisher","DOI":"10.1002\/9783527613601"},{"key":"e_1_2_7_6_2","doi-asserted-by":"publisher","DOI":"10.1007\/3-540-44421-1"},{"key":"e_1_2_7_7_2","unstructured":"\u00a0"},{"key":"e_1_2_7_8_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar50015a004"},{"key":"e_1_2_7_9_2","doi-asserted-by":"publisher","DOI":"10.1021\/ar50053a002"},{"key":"e_1_2_7_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/0022-328X(95)00309-E"},{"key":"e_1_2_7_11_2","doi-asserted-by":"publisher","DOI":"10.1021\/om970610g"},{"key":"e_1_2_7_12_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja0346431"},{"key":"e_1_2_7_13_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja005580e"},{"key":"e_1_2_7_14_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja0209060"},{"key":"e_1_2_7_15_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja010331r"},{"key":"e_1_2_7_16_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.279.5359.2080"},{"key":"e_1_2_7_16_3","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3757(20021104)114:21<4178::AID-ANGE4178>3.0.CO;2-2"},{"key":"e_1_2_7_16_4","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3773(20021104)41:21<4006::AID-ANIE4006>3.0.CO;2-I"},{"key":"e_1_2_7_17_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja001739b"},{"key":"e_1_2_7_18_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja962736v"},{"key":"e_1_2_7_19_2","doi-asserted-by":"publisher","DOI":"10.1021\/om970414"},{"key":"e_1_2_7_20_2","unstructured":"See Supporting Information."},{"key":"e_1_2_7_21_2","unstructured":"Additional experiments showed that the intensity ratio (A\/B) measured on the frozen solution spectra was sensitive to additional factors such as the concentration ratio of sodium naphthalenide\/phosphinine2."},{"key":"e_1_2_7_22_2","unstructured":"At 100 K only the B lines in Figure 3\u2009a were observed after reduction was carried out with sodium naphthalenide in the absence of cryptand. Although a frozen solution spectrum could not be clearly recorded upon reduction of2with a sodium mirror a broad doublet (40 G) was observed at 200 K. The signals observed upon reduction with naphthalenide or alkali metal were also detected after in situ electrolysis of a THF solution of2in the EPR cavity. However with this method additional lines were observed that can tentatively be attributed to protonation of the radical anion by traces of water in the electrolytic cell."},{"key":"e_1_2_7_23_2","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4613-0075-5_10"},{"key":"e_1_2_7_24_2","unstructured":"The drastic diminution of the central part of the frozen solution spectrum as a result of an overlap of the \u201cperpendicular\u201d transitions of an axial31P tensor is reminiscent of previous observation made for phosphinyl radicals."},{"key":"e_1_2_7_25_2","first-page":"577","volume":"30","author":"Preston J. Morton and K.","year":"1978","journal-title":"J. Magn. Reson."},{"key":"e_1_2_7_26_2","unstructured":"We cannot exclude that an intermolecular one\u2010electron P\uf8ffP bond is not formed in the frozen solution. Such a reaction between a localized radical anion and a neutral phosphinine would decrease the amount of localized radical anions responsible for signals of type A1 and A2."},{"key":"e_1_2_7_27_2","unstructured":"E. D. Glendening A. E. Reed J. E. Carpenter F. Weinhold. Natural Bond Orbital Analysis NBO 3.1;"},{"key":"e_1_2_7_27_3","unstructured":"Theoretical Chemistry Institute University of Wisconsin Madison WI"},{"key":"e_1_2_7_28_2","unstructured":"Although the calculated isotropic coupling with theparaprotons is around 4 G the corresponding splitting is not detected in the spectrum. This can arise either because of a slight difference between the real and calculated geometries (absence of phenyl in the model system) or because of molecular motion which alters the line shape. When couplings are calculated with a triple zeta basis set the31P isotropic couplings increase while the1H isotropic couplings decrease."},{"key":"e_1_2_7_29_2","unstructured":"Gaussian 03 Revision B.03 M. J. Frisch G. W. Trucks H. B. Schlegel G. E. Scuseria M. A. Robb J. R. Cheeseman J. A. Montgomery Jr. T. Vreven K. N. Kudin J. C. Burant J. M. Millam S. S. Iyengar J. Tomasi V. Barone B. Mennucci M. Cossi G. Scalmani N. Rega G. A. Petersson H. Nakatsuji M. Hada M. Ehara K. Toyota R. Fukuda J. Hasegawa M. Ishida T. Nakajima Y. Honda O. Kitao H. Nakai M. Klene X. Li J. E. Knox H. P. Hratchian J. B. Cross C. Adamo J. Jaramillo R. Gomperts R. E. Stratmann O. Yazyev A. J. Austin R. Cammi C. Pomelli J. W. Ochterski P. Y. Ayala K. Morokuma G. A. Voth P. Salvador J. J. Dannenberg V. G. Zakrzewski S. Dapprich A. D. Daniels M. C. Strain O. Farkas D. K. Malick A. D. Rabuck K. Raghavachari J. B. Foresman J. V. Ortiz Q. Cui A. G. Baboul S. Clifford J. Cioslowski B. B. Stefanov G. Liu A. Liashenko P. Piskorz I. Komaromi R. L. Martin D. J. Fox T. Keith M. A. Al\u2010Laham C. Y. Peng A. Nanayakkara M. Challacombe P. M. W. Gill B. Johnson W. Chen M. W. Wong C. Gonzalez J. A. Pople Gaussian Inc. Pittsburgh PA 2003."},{"key":"e_1_2_7_30_2","unstructured":"\u00a0"},{"key":"e_1_2_7_31_2","doi-asserted-by":"publisher","DOI":"10.1063\/1.464913"},{"key":"e_1_2_7_32_2","doi-asserted-by":"crossref","first-page":"785","DOI":"10.1103\/PhysRevB.37.785","volume":"54","author":"Lee C.","year":"1988","journal-title":"Phys. Rev."},{"key":"e_1_2_7_33_2","doi-asserted-by":"publisher","DOI":"10.1139\/v92-079"},{"key":"e_1_2_7_34_2","unstructured":"Flukiger P. Development of Molecular Graphics Package MOLEKEL Ph. D. 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