Homo- and heterochiral dimers (PHFX)2, X = Cl, CN, CH3, NC: To what extent do they differ?
Ab initio MP2/aug’-cc-pVTZ calculations have been performed to determine if intermolecular P–P distances, Z–P–P angles, binding energies, 31P chemical shieldings, or EOM–CCSD spin–spin coupling constants can differentiate between corresponding C2 (homochiral) and Ci (heterochiral) dimers (PHFX)2, X = Cl, CN, CH3, NC. With one exception, Ci isomers have shorter P–P distances than corresponding C2 isomers. Neither binding energies, Z–P–P angles, chemical shieldings, nor spin–spin coupling constants 1pJ(P–P) exhibit patterns which distinguish between corresponding C2 and Ci isomers. 1pJ(P–P) values correlate linearly with P–P distances, so that experimental values of 1pJ(P–P) could be used to extract intermolecular P–P distances.