Does Hydrogen Bonding Matter in Crystal Engineering? Crystal Structures of Salts of Isomeric Ions

Abstract

The preparation and structure determinations of the crystalline salts [3,3'-H(2)bipy][PtCl(4)] (2), [2,2'-H(2)bipy][PtCl(4)] (3) and [1,4'-Hbipy][PtCl(4)] (4) and [3,3'-H(2)bipy][SbCl(5)] (6) and [1,4'-Hbipy][SbCl(5)] (8) are reported. In addition a redetermination of the structure of the metastable salt [4,4'-H(2)bipy][SbCl(5)] (5 b) in the corrected space group Pbcm is described. These structures are compared to those of the known salt [4,4'-H(2)bipy][PtCl(4)] (1), the stable triclinic form of [4,4'-H(2)bipy][SbCl(5)] (5 a) and [2,2'-H(2)bipy][SbCl(5)] (7). In the case of the salts of the rigid [PtCl(4)](2-) ion, structures 2, 3 and 4 are essentially isostructural despite the differing hydrogen-bonding capability of the cations. Similarly, among the salts of [SbCl(5)](2-) ions, structures 7 and 8 are essentially isostructural. Structure 6 differs from these in having a differing pattern of aggregation of the [SbCl(5)](2-) ions to form polymeric rather than tetrameric units. It is evident that local hydrogen-bonding interactions, although significant, are not the only or even the decisive influence on the crystal structures formed by these salts. These observations are not in good accord with the heuristic "sticky tecton" or supramolecular synthon models for synthetic crystallography or crystal engineering.

Crystal Engineering: A Holistic View

“…[59,60,64] What is largely unexplored is the use of some of the more exotic varieties (organometallic, [65,66] charge-assisted, [67] blue-shifted [68] ) in routine crystal engineering. Molecular inorganic systems have also been studied; [69] the well-known aurophilic Au···Au interaction is described in a crystal engineering context. [70] The uranyl group has also been mentioned.…”

Crystal structure of 2,2’-bipyridindiium (2,2’-bipyridyl-κ2N,N’)- tetrabromidorhodate(III) bromide, (C10H10N2)[RhBr4(C10H8N2)]Br, C20H18Br5N4Rh

“…Among them the particularly important role is played by 4,4'-and 2,2'-bipyridines that belong to the most frequently used oligopyridine organic components in crystal engineering of inorganic-organic hybrids [1,2]. We have recently reported structural, spectroscopic and thermoanalytical properties of the hybrid material [4,4' ,astrategythatwas successfully applied before using flexible a,w-diammonio ions of medium chain lengthso rs emiflexible 1,4-diazoniacycloheptane ions [4][5][6].…”

Kristall‐Engineering: eine holistische Darstellung

“…[59,60,64] Allerdings ist die Verwendung einiger der exotischeren Spielarten (metallorganisch, [65,66] ladungsunterstützt, [67] blauverschoben [68] ) für ein routinemäßiges Kristall-Engineering wenig erforscht. Es sind auch molekulare anorganische Systeme untersucht worden, [69] und die gut bekannte aurophile Au···Au-Wechselwirkung wird im Zusammenhang des Kristall-Engineerings beschrieben. [70] Auch die Uranylgruppe ist erwähnt worden.…”