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Spontaneous Phosphorus‐Halogen Bond Cleavage in N‐Heterocyclic Halogenophosphanes Revisited: The Case of P–Br and P–I Bonds |
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| Authors: | Sebastian Burck Dietrich Gudat Prof Dr Martin Nieger Zoltan Benkö Lászlo Nyulászi Denes Szieberth |
| Institution: | 1. Institut für Anorganische Chemie, Universit?t Stuttgart, D‐70560 Stuttgart, Germany;2. Current address: Section Organic and Inorganic Chemistry, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands;3. Laboratory of Inorganic Chemistry, University of Helsinki, A.I. Virtasen aukio 1, Helsinki, Finland;4. Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, H‐1111 Budapest, Fax: +36‐1‐463‐36‐42 |
| Abstract: | P‐bromo‐ and P‐Iodo‐substituted N‐heterocyclic phosphanes (NHP) were synthesized by halogen exchange starting from the P‐chloro compound and characterized by spectroscopic data and X‐ray diffraction studies. Whereas the Br‐NHP still forms a molecular crystal, the solid‐state structure of the I‐derivative consists of ion‐pairs which assemble via secondary P···I interactions to form one‐dimensional coordination polymers. Computational studies indicate that the bond dissociation is due to a combination of intramolecular stabilisation (aromatisation of the phosphenium cation formed) and intermolecular Lewis‐acid/base interactions. Reaction of the I‐NHP with I2 proceeded under complete P–I bond cleavage to give an ionic phosphenium triiodide whose single‐crystal X‐ray diffraction study revealed a unique supramolecular structure. |
| Keywords: | Phosphanes Halides Bond dissociation X‐ray Diffraction DFT Studies |