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DALTON COMMUNICATION J. Chem. Soc., Dalton Trans., 1997, Pages 2381–2382 2381 Gas phase inorganic synthesis: copper sulfide cluster anions react with phosphorus, P4, to generate copper compounds with PmSn ligands Keith Fisher and Ian Dance School of Chemistry, University of New South Wales, Sydney 2052, Australia Anions [CuxSy]2 reacted with P4 (g) to form products which were formally addition of P2 units, but are shown by density functional calculations and collisional induced dissociation to contain PnSm ligands co-ordinated to copper; the reactivities of the [CuxSy]2 ions correlate with their geometrical rather than electronic structures, according to the principles which are described.The scope for syntheses of inorganic compounds in the gas phase is less well developed for negative ion precursors than for positive ions, partly because the lesser general reactivities of negative inorganic ions 1 have limited investigations using them. Recently we revealed 2 that metal sulfide anions are unusually reactive with S8, H2S and thiols, although not with oxygen homologues.We now report that [CuxSy]2 (x = 1–6, y = 2–4) ions also react with P4 (g) to generate copper compounds with PmSn ligands (m = 2, n = 1 or 2), presaging general synthesis of more complex and significant inorganic systems,3 and we describe the relevant principles of structure and reactivity. Table 1 lists the products of reaction of eight [CuxSy]2 ions with P4 (g), and the relative rates of reaction under the same conditions.* The ions [CuS2]2, [CuS3]2 and [Cu2S3]2 react rapidly to add one P2 unit, [Cu4S3]2 rapidly adds one and then a second P2 unit, [Cu2S2]2 adds three P2 units sequentially, the ions [Cu3S3]2 and [Cu5S4]2 add one or two P2 units respectively but very much more slowly than the others, and [Cu6S4]2 does not react.There is no evidence of direct addition of intact P4, and the relative rates of reaction are clearly determined by factors other than size of the anion.This is in contrast to the rates of reaction of Cn 2 ions with P4 (g) which decrease monotonically with n.4 The structures of [CuxSy]2 and of the products of reaction with P4 were investigated using density functional calculations.† The notation x/y and x/y/z is used for ions [CuxSy]2 and [Cux- SyPz]2 respectively, and isomers of each are labelled with letters A, B, C. The most stable isomers for the eight CuxSy anions from [CuS2]2 to [Cu6S4]2 are shown in Fig. 1. While [CuS2]2 is linear (1/2A), the [Cu(S3)]2 isomer 1/3A is 150 kJ mol21 more stable than the trigonal planar [Cu(S)3]2 isomer. For [Cu2S3]2 the best connectivity is S]Cu]S]Cu]S, with the bent isomer 2/3A only 4 kJ mol21 more stable than the fully linear extended isomer: this demonstrates that linear S]Cu]S local coordination is a major factor while Cu]Cu interaction is a minor influence. The anion [Cu3S3]2 is the D3h isomer Cu3(m-S)3, while for [Cu4S3]2 the isomer 4/3A which allows linear local S]Cu]S co-ordination at two Cu but distortions at the other two Cu is 113 kJ mol21 more stable than the next best isomer.[The S- * The uncorrected gauge pressure of P4 (g) was 1 × 1025 Pa. The [CuxSy]2 ions were generated by laser ablation of Cu2S, and the reactions investigated by Fourier-transform ion cyclotron resonance mass spectrometry, following procedures previously described.2 † The Becke–Lee–Yang–Parr functional was used, with numerical basis sets; program DMol, MSI, San Diego, CA, USA.void cubane isomer, Cu4(m3-S)3, converts to 4/3A.] The best [Cu5S4]2 isomer is 5/4A which allows approximately linear coordination at all Cu, and is effectively two fused 3/3A. The high symmetry (Td) isomer 6/4A allows approximately linear S]Cu]S co-ordination at all Cu atoms. The reactivity of the [CuxSy]2 ions with P4 correlates with the geometrical structure of [CuxSy]2, specifically higher reactivity correlates with the occurrence of either (1) terminal CuS coordination (e.g. 1/2A or 2/3A), or (2) Cu atoms without linear SCuS co-ordination (e.g. 2/2A or 4/3A), or (3) undercoordinate

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