Through-Space Spin-Spin Coupling In Acetylenic Systems. Ab Initio and DFT Calculations

International Journal of Molecular Sciences

Alessandro Bagnoa¹  Girolamo Casellab²  Giacomo Saiellia³ 

[1] Dipartimento di Chimica Inorganica e Analitica "Stanislao Cannizzaro", Università di Palermo, Viale delle Scienze Parco d'Orleans II, 90128 Palermo (Italy);aIstituto per la Tecnologia delle Membrane del CNR, Sezione di Padova, Dipartimento di Chimica Organica, Università di Padova, Via Marzolo 1, 35131 Padova (Italy)

关键词: Through-space coupling;    NMR;    ab initio;    DFT;   

DOI  :  10.3390/i4040193

来源: mdpi

【 摘 要 】

We have investigated, by means of ab initio and DFT calculations, the magnitude of through-space spin-spin couplings (J_CH and J_HH) in CH/π bonded van der Waals dimers involving acetylene, and in a structurally related covalent compound (4-ethynylphenanthrene). Within regions where the interaction is stabilizing J_HH couplings are very small (< 0.1 Hz) for all complexes. In the acetylene-methane complex J_CH is also very small, whereas in the acetylene-benzene complex and the acetylene dimer it shows a relatively large dependence on the tilt angle from the T-shaped arrangement, for which the smallest values are calculated, to a parallel slipped arrangement where J_CH is ca. 0.5 Hz. The relative magnitude of through-space couplings in 4-ethynylphenanthrene and a tilted acetylene-benzene dimer, featuring the same internuclear arrangement as in model dimers, are compared.

【 授权许可】

Unknown   
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