TY - JOUR

T1 - Hypervalency in organic crystals

T2 - A case study of the oxicam sulfonamide group

AU - Tantardini, Christian

AU - Boldyreva, Elena V.

AU - Benassi, Enrico

PY - 2016/12/8

Y1 - 2016/12/8

N2 - The theoretical charge density of the active pharmaceutical ingredient piroxicam (PXM) was evaluated through density functional theory with a localized basis set. To understand the electronic nature of the sulfur atom within the sulfonamide group, a highly ubiquitous functional group in pharmaceutical molecules, a theoretical charge density study was performed on PXM within the framework of Bader theory. Focus is on developing a topological description of the sulfur atom and its bonds within the sulfonamide group. It was found that sulfur d-orbitals do not participate in bonding. Instead, the existence of a strongly polarized ("ionic") bonding structure is found through a combined topological and natural bonding orbital analysis. This finding is in stark contrast to long-held theories of the bonding structure of organic sulfonamide and has important implications for the parametrization of calculations using classical approaches. (Chemical Equation Presented).

AB - The theoretical charge density of the active pharmaceutical ingredient piroxicam (PXM) was evaluated through density functional theory with a localized basis set. To understand the electronic nature of the sulfur atom within the sulfonamide group, a highly ubiquitous functional group in pharmaceutical molecules, a theoretical charge density study was performed on PXM within the framework of Bader theory. Focus is on developing a topological description of the sulfur atom and its bonds within the sulfonamide group. It was found that sulfur d-orbitals do not participate in bonding. Instead, the existence of a strongly polarized ("ionic") bonding structure is found through a combined topological and natural bonding orbital analysis. This finding is in stark contrast to long-held theories of the bonding structure of organic sulfonamide and has important implications for the parametrization of calculations using classical approaches. (Chemical Equation Presented).

UR - http://www.scopus.com/inward/record.url?scp=85018944582&partnerID=8YFLogxK

U2 - 10.1021/acs.jpca.6b10703

DO - 10.1021/acs.jpca.6b10703

M3 - Article

C2 - 27983840

AN - SCOPUS:85018944582

VL - 120

SP - 10289

EP - 10296

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

IS - 51

ER -