Exploring the salt-cocrystal continuum with solid-state NMR using natural-abundance samples: implications for crystal engineering.

ABSTRACT: There has been significant recent interest in differentiating multicomponent solid forms, such as salts and cocrystals, and, where appropriate, in determining the position of the proton in the X-H⋯A-YX^-⋯H-A⁺-Y continuum in these systems, owing to the direct relationship of this property to the clinical, regulatory and legal requirements for an active pharmaceutical ingredient (API). In the present study, solid forms of simple cocrystals/salts were investigated by high-field (700 MHz) solid-state NMR (ssNMR) using samples with naturally abundant ¹⁵N nuclei. Four model compounds in a series of prototypical salt/cocrystal/continuum systems exhibiting {PyN⋯H-O-}/{PyN⁺-H⋯O^-} hydrogen bonds (Py is py

SUBMITTER: Rajput L 

PROVIDER: S-EPMC5571809 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature