Structure of tris(cyclohexylammonium) phosphoenolpyruvate monohydrate and crystal chemistry of phosphoenolpyruvates

Abstract

The crystal structure of (C6H11NH3 +)3.Pep3−.H2O, where Pep3− = (O−)2P(O)—O—C(CH2)—CO− 2, is reported and the systematic structural variations among 19 crystallographic occurrences of H3Pep, H2Pep−, HPep2− and Pep3− species, which are important phosphate donors in the ATP cycle of bioenergetics, are reviewed. Tris(cyclohexylammonium) phosphoenolpyruvate monohydrate, (C6H11NH3 +)3.[O3POC(CH2)CO2]3−.H2O, Mr = 483.6, m.p. 418–420 K; T = 296 (1) K; orthorhombic, P212121; a = 16.7042 (5), b = 24.4881 (6), c = 6.38910 (10) Å; V = 2613.49 (11) Å3, Z = 4, Dx = 1.23, Dm = 1.22 mg mm−3, μ = 0.14 mm−1 for λ(MoKα) = 0.7107 Å; F = 1056 e; R(|F|) = 0.0608 for 6056 hkl and hk\bar l data with (sin θ)/λ ≤ 0.65 Å−1.