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Racemic Compound Formation versus Conglomerate Formation with [M(bpy) 3 ](PF 6 ) 2 (M = Ni, Zn, Ru); Lattice Energy Minimisations and Implications for Structure Prediction
Author(s) -
Breu Josef,
Domel Holger,
Norrby PerOla
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200011)2000:11<2409::aid-ejic2409>3.0.co;2-t
Subject(s) - intermolecular force , chemistry , lattice energy , crystal structure , crystal structure prediction , molecular mechanics , chemical physics , lattice (music) , molecular dynamics , computational chemistry , crystallography , molecule , molecular geometry , organic chemistry , physics , acoustics
Polymorphism observed with [M(bpy) 3 ](PF 6 ) 2 (M = Ru, Ni, Zn) offers a unique opportunity to study the impact of different intermolecular packing motifs on lattice energies. Additionally, it allows us to test the accuracy of empirical intermolecular potentials, because these compounds represent an example of a system where a small change in molecular geometry already induces a qualitatively different crystal packing. Lattice energy minimisations for these three compounds applying both, rigid body and flexible body approaches, are reported. The calculations quite reasonably reproduce the crystallisation behaviour observed in this heteropolymorphic series. We conclude that the state‐of‐the‐art approach and all four tested empirical intermolecular potentials are adequate for these organometallic compounds. However, it is crucial to input the most accurate molecular structures. Molecular structures determined by X‐ray analysis need to be corrected for the apparent bond shrinkage due to librational motion. When these molecular structures are to be obtained by Molecular Mechanics or Quantum Mechanics methods the highest possible accuracy is required. Our results suggest that routine polymorph prediction may be more severely hampered by inaccuracies in molecular structures than by inadequacies in the intermolecular potentials. The key to a successful structure prediction is therefore the input of reliable molecular structures.