4,5-Dimethoxycyclopent-4-ene-1,2,3-trione

Abstract

The title compound (alternative name dimethyl croconate), C7H6O5, is the first example of a croconate ether. The mol­ecule is essentially planar and exhibits a local symmetry (C2v) that is different from that shown by the croconate dianion (C5h), indicating that the geometry of these compounds is very sensitive to the electric charge state.

Coordination polymers of CdII and PbII with croconate show remarkable differences in coordination patterns: a structural and spectroscopic study

“…the charge-localized C 2v and the charge-delocalized D 5h mode, which have been shown to be stabilized within a crystal structure (Lam et al, 2004). The O atoms of croconate can engage in chemical reactions, whether through addition, creating croconate ethers (Chen et al, 2005), or through substitution reactions (Seitz & Imming, 1992). While this makes croconate quite useful in building large crystal superstructures, the difficulty in synthesizing croconate on a large scale has limited the volume of croconate research (Seitz & Imming, 1992).…”