title: NMR Investigations of Noncovalent Carbon Tetrel Bonds. Computational Assessment and Initial Experimental Observation.
abstract: Group IV tetrel elements may act as tetrel bond donors, whereby a region of positive electrostatic potential (σ-hole) interacts with a Lewis base. The results of calculations of NMR parameters are reported for a series of model compounds exhibiting tetrel bonding from a methyl carbon to the oxygen or nitrogen atoms in various functional groups. The (13)C chemical shift (δiso) and the (1c)J((13)C,Y) coupling (Y = (17)O, (15)N) across the tetrel bond are recorded as a function of geometry. The sensitivity of the NMR parameters to the noncovalent interaction is demonstrated via an increase in δiso and in |(1c)J((13)C,Y)| as the tetrel bond shortens. Gauge-including projector-augmented wave density functional theory (DFT) calculations of δiso are reported for crystals that exhibit tetrel bonding in the solid state. Experimental δiso values for solid sarcosine and its tetrel-bonded salts corroborate the computational findings. This work offers new insights into tetrel bonding and facilitates the incorporation of tetrel bonds as restraints in NMR crystallographic structure refinement.
authors.affiliation: Department of Chemistry and Biomolecular Sciences & Centre for Catalysis Research and Innovation, University of Ottawa , 10 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Southern
authors.affiliation: Department of Chemistry and Biomolecular Sciences & Centre for Catalysis Research and Innovation, University of Ottawa , 10 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: David L
authors.initials: DL
authors.lastname: Bryce