Nuclear chemical shielding tensors (CSTs) provide valuable information on structural and dynamic properties of molecular fragments in the solid state, and they are often exploited to obtain a detailed character- ization of reorientational or interconformational motions in the kilohertz regime. In this work, we introduce a new combined computational DFT and experimental solid-state NMR approach to investigate the effects of small- amplitude vibrational motions on 13C CSTs. This approach was tested on ibuprofen, for which the influence of reorientational motions on CSTs could be ruled out from a previous detailed investigation of its dynamic properties. The data relative to the carbons belonging to the phenyl moiety were analyzed and discussed in terms of phenyl ring librations and in-plane and out-of-plane CH bendings.
13C Chemical Shielding Tensors: A Combined Solid-State NMR and DFT Study of the Role of Small-Amplitude Motions
BORSACCHI, SILVIA;MENNUCCI, BENEDETTA;GEPPI, MARCO
2011-01-01
Abstract
Nuclear chemical shielding tensors (CSTs) provide valuable information on structural and dynamic properties of molecular fragments in the solid state, and they are often exploited to obtain a detailed character- ization of reorientational or interconformational motions in the kilohertz regime. In this work, we introduce a new combined computational DFT and experimental solid-state NMR approach to investigate the effects of small- amplitude vibrational motions on 13C CSTs. This approach was tested on ibuprofen, for which the influence of reorientational motions on CSTs could be ruled out from a previous detailed investigation of its dynamic properties. The data relative to the carbons belonging to the phenyl moiety were analyzed and discussed in terms of phenyl ring librations and in-plane and out-of-plane CH bendings.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
