Preparation and Characterization of <i>N</i>,<i>N′</i>‐Dialkyl‐1,3‐propanedialdiminium Chlorides, <i>N</i>,<i>N′</i>‐Dialkyl‐1,3‐propanedialdimines, and Lithium <i>N</i>,<i>N′</i>‐Dialkyl‐1,3‐propanedialdiminates

We describe convenient preparations of N,N′-dialkyl-1,3-propanedialdiminium chlorides, N,N′-dialkyl-1,3-propanedialdimines, and lithium N,N′-dialkyl-1,3-propanedialdiminates in which the alkyl groups are methyl, ethyl, isopropyl, or tert-butyl. For dialdiminium salts, N2C3 backbone is always trans-s-trans configuration. Three isomers present solution except for tert-butyl compound, only two present; increasing steric bulk N-alkyl substituents shifts equilibrium away from (Z,Z) isomer favor (E,Z), (E,E) isomers. neutral dialdimines, crystal structures show that methyl isopropyl compounds adopt (E,Z) form, whereas compound form. In aprotic solvents all four dialdimines (as well as dialdiminate salts) cis-s-cis conformations there presumably either an intramolecular hydrogen bond (or a cation) between nitrogen atoms.