The Structural Systematics of Protonation of Some Important Nitrogen‐base Ligands. IV. Some Ethane‐1,2‐diaminium Univalent Anion Salt/1,10‐Phenanthroline (Hydrate) Arrays

Abstract

Abstract Syntheses and single crystal X‐ray structure characterisations are recorded for some novel series of crystalline complexes formed between salts of univalent anions of the ethane‐1,2‐diaminium cation, [enH 2 ]X 2 , and 1,10‐phenanthroline (‘phen’), variously hydrated, thus: [enH 2 ]X 2 · m phen(· n H 2 O), for m = 2, 4 and 10 (one example), n various. In all cases, the motifs constituting the arrays comprise columns of [enH 2 ] 2+ cations, carrying the protonic array but linked in a second dimension by hydrogen‐bonding to associated anions and water molecules (where present), expanding the column in some cases to form a sheet, different degrees of hydration compensating for changing anion bulk. In a third dimension the protonic hydrogen complement also links to the nitrogenous component of phen stacks which surround the column. Thus, for the m = 2 array, in a triclinic $P{\bar 1}$ cell, a , b , c broadly 10‐11 (x2), 7Å, α, β, γ 80, 70° (x2), the cation and phen columns lie parallel to c ; in the unsolvated trichloroacetate compound, the cation column is associated with anions to either side, these linking into a sheet with water molecules in the more highly hydrated trifluoroacetate (‘tfa’) and nitrate ( n = 2), and chloride and bromide ( n = 4) arrays (the tfa adduct a superlattice doubled in c ). In the m = 4 arrays, an additional phen stack is inserted, forming a sheet with the first in the second dimension for the perchlorate tetrahydrate array, the iodide pentahydrate counterpart being a 2 x c superlattice. A second nitrate salt, m = 10, n = 4, is also described, a complex array of multiple networks of the above type. Single crystal X‐ray structure determinations are also recorded for salts [phenH](PF 6 )·phen and [2,9‐Me 2 phenH](PF 6 ). In the phen adduct, the protonic hydrogen atom is closely associated (N···H 0.90(4) Å) with one of the two independent phen moieties, these disposed alternately in a stack up b close to the 2 1 screw axis, so that the hydrogen bridges to the unprotonated moiety (H···N′ 2.36(4) Å) pitched at an angle of 47° to it in the screw‐related stack. In the Me 2 phen salt, the phen moieties lie in crystallographic mirror planes, normal to and stacked up b , with the protonic hydrogen atom contacting a PF 6 fluorine atom (H···F 1.96(3) Å). The structure of unsolvated Me 2 phen is also recorded.