Generation and Characterization of Diphosphene and Triphosphene Radical Anions. Computational Studies on the Structure and Stability of P3H3g src="http://pubs.acs.org/ima

详细信息    查看全文

• 作者：Herbert Binder ; Bernhard Riegel ; Gernot Heckmann ; Michael Moscherosch ; Wolfgang Kaim ; Hans-Georg von Schnering ; W. Hö ; nle ; Heinz-Jü ; rgen Flad ; and Andreas Savin
• 刊名：Inorganic Chemistry
• 出版年：1996
• 出版时间：March 27, 1996
• 年：1996
• 卷：35
• 期：7
• 页码：2119 - 2126
• 全文大小：240K
• 年卷期：v.35,no.7(March 27, 1996)
• ISSN：1520-510X

文摘

Complexation of the K⁺ ions of little solubleK₂[^tBuP]₂·¹/₂THF(THF = tetrahydrofuran) with 18-crown-6 or[2.2.2]cryptand in THF leads to brown-red solutions whichexhibit limited stability at room temperature. The³¹PNMR spectrum consists of two singlets (1:1) which are assigned to thetrans and gauche rotamers of thedianion[^tBuP-P^tBu]^2-.That dianion undergoes a protonation by the solvent forming themonoanion[(^tBu)(H)P-P^tBu]^-,which has been characterized by ³¹P NMR spectroscopy.In addition, the brown-red solutions contain aparamagnetic species, for which the EPR spectrum revealed a 1:2:1triplet caused by the hitherto unknowndiphosphene radical anion[^tBuP=P^tBu]^{ges/entities/bull.gif">-}(g_iso = 2.0103). These reactions of thedianion[^tBuP-P^tBu]^2-oncomplexation of the K⁺ ions occur also at -40 ges/entities/deg.gif">C andcan be attributed to a tendency to reduce the Coulombicrepulsion between the adjacent negative charges. The homologoustriphosphene radical anion[^tBuP-(^tBu)P-P^tBu]^{ges/entities/bull.gif">-} couldbe generated by reduction of the cyclic triphosphane(^tBuP)₃ on a potassium mirror.The newtriphosphene radical anion was identified by its EPR spectrum whichshowed a triplet of doublets (g_iso =2.0098).Finally, reduction of the neutral valence isoelectronic cyclicdiphosphirane(CH₃)₂C(^tBuP)₂on a potassium mirroryields the radical anion[(CH₃)₂C(^tBuP)₂]^{ges/entities/bull.gif">-},which exhibits a 1:2:1 triplet in the EPR spectrum(g_iso = 2.0060).The triphosphene radical anion[^tBuP-(^tBu)P-P^tBu]^{ges/entities/bull.gif">-}is related to the radical anionsO₃^{ges/entities/bull.gif">-},S₃^{ges/entities/bull.gif">-} andP₃^{ges/entities/bull.gif">4-},butin contrast to O₃^{ges/entities/bull.gif">-} andS₃^{ges/entities/bull.gif">-}, the pattern of hyperfinecoupling constants is "reversed".Quantum-chemicalcalculations of[P₃H₃]^{ges/entities/bull.gif">-} suggestan open-chain structure for[^tBuP-(^tBu)P-P^tBu]^{ges/entities/bull.gif">-}.A possible explanation isgiven for the reversion of the hyperfine coupling pattern due to theshape of the highest occupied orbital. Theadiabatic electron affinities are calculated for two possiblestructures of[P₃H₃]^{ges/entities/bull.gif">-}.