The structure of b-diketones related to curcumin determined by X-ray crystallography, NMR (solution and solid state) and theoretical calculations

Abstract

<style type="text/css">p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: "Times New Roman",serif; font-size: 12pt; }p.cjk { font-family: "Times New Roman",serif; font-size: 12pt; }p.ctl { font-family: "Times New Roman",serif; font-size: 12pt; }a:visited { color: rgb(128, 0, 128); }a.western:visited { }a.cjk:visited { }a.ctl:visited { }a:link { color: rgb(0, 0, 255); }Structural data are reported on sixteen ketoenols of β-diketones:solution NMR, solid-state NMR (CPMAS and MAS) and X-raycrystallography (eight compounds, where three are new). The emphasisis on the tautomerism between both ketoenols, in solution and in the solid statep { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: "Times New Roman",serif; font-size: 12pt; }p.cjk { font-family: "Times New Roman",serif; font-size: 12pt; }p.ctl { font-family: "Times New Roman",serif; font-size: 12pt; }a:visited { color: rgb(128, 0, 128); }a.western:visited { }a.cjk:visited { }a.ctl:visited { }a:link { color: rgb(0, 0, 255); }</style>Structural data are reported in sixteen ketoenols of beta diketones, solution NMR, solid-state NMR<br />(CPMAS and MAS) and X-ray crystallography (four compounds, where three are new). The emphasis is on the tautomerist between both ketoenols, both in solution and solid-state. GIAO-B3LYP 6-311g (d,p) and Quantum ESPRESSO (QE) calculations were used and compared. For average values, the GIAO-DMSO-PCM is enough but splittings can only be approached by using QE. A case of rotational disorder has been analyzed. Some anomalies related to C-F bonds and to the C-CF₃ group have been detected.