3hJ(15N-31P) Spin-Spin Coupling Constants across N-H···O-P Hydrogen Bonds

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• 作者：Janet E. Del Bene ; S. Ajith Perera ; Rodney J. Bartlett ; José ; Elguero ; Ibon Alkorta ; Carmen Ló ; pez-Leonardo ; and Mateo Alajarin
• 刊名：Journal of the American Chemical Society
• 出版年：2002
• 出版时间：June 5, 2002
• 年：2002
• 卷：124
• 期：22
• 页码：6393 - 6397
• 全文大小：59K
• 年卷期：v.124,no.22(June 5, 2002)
• ISSN：1520-5126

文摘

Equation-of-motion coupled cluster singles and doubles (EOM-CCSD) calculations have beenperformed to evaluate three-bond ¹⁵N-³¹P coupling constants (^3hJ_N-P) across N-H···O-P hydrogen bondsin model cationic and anionic complexes including NH₄⁺:OPH, NH₄⁺:OPH₃, NH₃:^-O₂PH₂, NFH₂:^-O₂PH₂,and NF₂H:^-O₂PH₂. Three-bond coupling constants can be appreciable when the phosphorus is P(V), butare negligible with P(III). ^3hJ_N-P values in complexes with cyclic or open structures are less than 1 Hz, aconsequence of the nonlinear arrangement of N, H, O, and P atoms. For complexes with these structures,^3hJ_N-P may not be experimentally measurable. In contrast, complexes in which the N, H, O, and P atomsare collinear or nearly collinear have larger values of ^3hJ_N-P , even though the N-P distances are longerthan N-P distances in cyclic and open structures. In linear complexes, ^3hJ_N-P is dominated by the Fermi-contact term, which is distance dependent. Therefore, N-P (and hydrogen-bonding N-O) distances inthese complexes can be determined from experimentally measured ¹⁵N-³¹P coupling constants.