Cyano‐stabilized triphenyl­phospho­nium ylids

Crystalline cyano‐stabilized triphenyl­phospho­nium ylids with keto or ester groups give rise to an extended electronic delocalization. In methyl 2‐cyano‐2‐(trimethyl­phospho­nio)­ethenoate, Ph₃P=C(CN)CO₂CH₃ or C₂₂H₁₈NO₂P, (I), and 1‐cyano‐1‐(trimethyl­phospho­nio)prop‐1‐en‐2‐olate, Ph₃P=C(CN)CO—CH₃ or C₂₂H₁₈NOP, (II), the carbonyl groups are oriented toward the cationoid P atom. Bond lengths and angles, torsion angles and P⋯O contact distances are consistent with a dominant coplanar conformation where the mol­ecular structures are the result of a balance between intra‐ and inter­molecular inter­actions. The main inter­actions presented by cyano‐ester (I) and cyano‐keto (II) are intra­molecular inter­actions between the carbonyl O and the P atoms. In addition, both compounds show other less important intra­molecular inter­actions between the carbonyl O and phenyl H atoms, which could contribute to form a preferred conformation in the crystal structure.