University of Oulu

Štěpánek, P., & Lantto, P. (2022). Unexpected NMR shieldings of sp- and sp 2 -hybridized carbon atoms in graphyne systems. Physical Chemistry Chemical Physics, 24(41), 25513–25521.

Unexpected NMR shieldings of sp- and sp²-hybridized carbon atoms in graphyne systems

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Author: Štěpánek, Petr1; Lantto, Perttu1
Organizations: 1NMR Research unit, Faculty of Science, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.7 MB)
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Language: English
Published: Royal Society of Chemistry, 2022
Publish Date: 2022-11-02


Graphynes (GYs) are two-dimensional alloptropic forms of carbon consisting of periodically arranged sp- and sp2-hybridized carbon atoms in a planar structure. Graphynes can be formally created from graphene by inserting sp-hybridized carbon links into selected points of the graphene lattice. Depending on where the links are introduced, several forms of graphynes have been proposed with properties that make them potential candidates for new generation electronics or for applications in chemical processes. Since the applications of each form of GY depend on its structure, it is of interest to experimentally distinguish different forms of graphynes. In this paper we propose nuclear magnetic resonance (NMR) as a potential method of choice for such distinction. We computationally investigate on the DFT level the ¹³C-NMR chemical shifts for α-, β-, γ-, rhombic, and 6,6,12-graphynes, and α- and γ-graphdiynes. We perform the calculations both in periodic systems and with approximate finite models. The results show that NMR chemical shifts in graphynes are dependent on the structure and reflect the local bonding around the carbon nucleus. Interestingly, NMR shifts of several graphynes show anomalous values, differing significantly from shifts found in typical sp²-hybridized systems. We analyze these results in terms of local structural parameters and qualitatively investigate the possible origins of these anomalous NMR shifts. The results show that NMR is a viable method for determining the structure of graphynes and their finite precursor molecules.

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Series: PCCP. Physical chemistry chemical physics
ISSN: 1463-9076
ISSN-E: 1463-9084
ISSN-L: 1463-9076
Volume: 24
Issue: 41
Pages: 25513 - 25521
DOI: 10.1039/D2CP03837D
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
114 Physical sciences
Funding: The authors acknowledge the financial support from the Academy of Finland (Grant 316180). The computational resources were provided by CSC – IT Center for Science (Espoo, Finland) and the Finnish Grid and Cloud Infrastructure project (persistent identifier urn:nbn:fi:research-infras-2016072533).
Academy of Finland Grant Number: 316180
Detailed Information: 316180 (Academy of Finland Funding decision)
Copyright information: This journal is © the Owner Societies 2022. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.