Understanding <sup>125</sup>Te NMR chemical shifts in disymmetric organo-telluride compounds from natural chemical shift analysis
Ewa Pietrasiak, Christopher P. Gordon, Christophe Copéret, Antonio Togni
Abstract
Te chemical shifts in molecules 1-13 is mainly due to the magnetic coupling of the tellurium p-character lone pair with antibonding orbitals perpendicular to it {σ*(Te-X) and σ*(Te-C(Ar))} upon action of an external magnetic field. The strength of the coupling is affected by electronic properties of the X-substituents, polarization of the antibonding orbitals and presence of secondary interactions perturbing the energy of these orbitals. The lower in energy and the more polarized towards tellurium the antibonding orbitals are, the stronger is the coupling and the more deshielded the tellurium nucleus.
Topics & Concepts
Chemical shiftTellurideChemistryLone pairComputational chemistryPhysical chemistryCrystallographyNuclear magnetic resonanceMoleculePhysicsOrganic chemistryOrganoselenium and organotellurium chemistryMolecular spectroscopy and chiralityCrystallography and molecular interactions