Crystal Synthesis of Organic−Inorganic Hybrid Salts Based on Tetrachloroplatinate and -palladate Salts of Organic Cations: Formation of Linear, Two-, and Three-Dimensional NH···Cl Hydrogen Bond Networks

A series of new crystal structures of salts containing [PtCl4]2- or [PdCl4]2- with organic cations containing pyridinium
and piperidinium groups have been prepared:  [4,4‘-H2bpe][PtCl4] (2), [4,4‘-H2bpethane][PtCl4] (3), [HNC5H4CO2H-4]2[PtCl4] (6a),
[HNC5H4CONH2-3]2[PtCl4] (8), [H2NC5H9CO2H-4]2[PtCl4] (9), [H2NC5H9CO2H-3]2[PtCl4] (10), [H2NC5H9CO2H-4]Cl (11), [HNC5H4CO2H-4]Cl (12), [4,4‘-H2bpe][PdCl4] (13), [4,4‘-H2bipip][PdCl4] (14a, 14b, 14c), [piperazinium][PdCl4]·2H2O (15), and [HNC5H4CO2H-4]2[PdCl4]·2H2O (16). The molecular recognition motifs formed in these and related structures are identified and discussed.
The robustness of these supramolecular synthons and their applicability in synthetic crystallography are analyzed. Cases of structural
mimicry of a molecule by a supramolecular dication (1 and 6a), isomorphism (2 and 3; 4 and 14a; 6 and 16), polymorphism
(14a−c), and “latent” polymorphism (2 and 13) are identified.