Syntheses, structures and DFT study of [W(CO) 5 (Ph 2 SbX)] X = Cl, Br, I H.J. Breunig a, * , T. Borrmann b , E. Lork a , C.I. Rat ß a a Institut fu ¨ r Anorganische und Physikalische Chemie, Fachbereich 2 der Universita ¨ t Bremen, Postfach 330 440, D-28334 Bremen, Germany b Institut fu ¨ r Organische Chemie, Fachbereich 2 der Universita ¨ t Bremen, Postfach 330 440, D-28334 Bremen, Germany Received 16 January 2007; received in revised form 26 February 2007; accepted 2 March 2007 Available online 12 March 2007 Abstract The complexes [W(CO) 5 (Ph 2 SbX)], X = Cl (1), Br (2) and I (3) were prepared by reaction of [W(CO) 5 (tetrahydrofuran)] with Ph 2 SbX. The structures of 1–3 were studied by X-ray diffraction. In the crystals there are weak contacts between the oxygen atoms of the CO ligands and antimony atoms of neighbouring molecules. DFT calculations were carried out for 1 using gradient corrected functional B3LYP. The bonding between Ph 2 SbCl and the W(CO) 5 fragment in 1 was analysed using charge decomposition analysis. Ó 2007 Elsevier B.V. All rights reserved. Keywords: Antimony; Tungsten; X-ray structure; DFT 1. Introduction Pentacarbonyl metal complexes with diorganoanti- mony halide ligands of the type [M(CO) 5 (R 2 SbX)] possess a functional group at antimony and hence they can be useful as antimony reagents with protection by the metal carbonyl fragment. The inspection of their crystal struc- tures and theoretical calculations allow to study the effect of coordination on the geometry of the R 2 SbX unit. Several complexes of this type have been synthesised [1–5]; none of them was studied by X-ray diffraction. We chose the series [W(CO) 5 (Ph 2 SbX)], X = Cl (1), Br (2) and I (3) for an inspection of the crystal structures and selected 1 for a study at the DFT level. The synthesis and characterisation of 1 [1] and the crystal structures of the free ligands Ph 2 SbX (X = Cl [6], Br [7],I [8]) were reported before. 2. Results and discussion [W(CO) 5 (Ph 2 SbCl)] (1) was prepared by the exchange reaction between [W(CO) 5 (THF)] (THF @ tetrahydrofu- ran) and diphenylantimony chloride as described by Wieber and Graf [1]. An analogous procedure led to [W(CO) 5 (Ph 2 SbX)] [X = Br (2), I (3)]. Yellow green (1) or yellow (2, 3) single crystals were obtained by cooling solu- tions in petroleum ether. The crystals are air stable and well soluble in organic solvents. Also thermally 1–3 are rela- tively stable. They melt without decomposition above 80 °C but become slowly brown after further heating of the liquids. The structures of 1–3 were determined by single crystal X-ray diffraction. The molecules are composed of pyramidal Ph 2 SbX units coordinated through the anti- mony atoms to tetragonal pyramidal W(CO) 5 fragments. The phenyl groups adopt a propeller like arrangement. As a representative example the structure of 3 is depicted in Fig. 1. Relevant bond lengths and bond angles of 1–3 and of the non-coordinated diphenylantimony halides are listed in Table 2. The Sb–W bonds in 1: 2.7184(10), 2: 2.7243(8), 3: 2.7256(7) A ˚ are slightly shorter than the corresponding 0022-328X/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2007.03.007 * Corresponding author. Tel.: +49 421 218 2266; fax: +49 421 218 4042. E-mail address: breunig@chemie.uni-bremen.de (H.J. Breunig). www.elsevier.com/locate/jorganchem Journal of Organometallic Chemistry 692 (2007) 2593–2598