Noble Gas Elements

ChemInform Abstract: The closo‐[Sn9M(CO)3]4‐ Zintl Ion Clusters where M: Cr, Mo, W: Two Structural Isomers and Their Dynamic Behavior.

“…This conclusion is based on the following results and observations: 1) Crystalline samples containing approximately 1:2 mixtures of the h 4 and h 5 isomers of 3 (solid-state IR analysis, see Figure 5 later) dissolve to give one set of 119 3) The chemical shifts and, more importantly, the SnÀSn coupling constants show temperature and solvent dependencies consistent with equilibrium mixtures of isomers. [29] The spectroscopic data supporting these conclusions are given below.…”

“…A detailed evaluation of the first-and second-order components of this complex will be reported by Schrobilgen et al in a subsequent publication. [29] The 119 Sn NMR spectrum of [Sn 9 W(CO) 3 ] 4À (3), shown in Figure 4, also has three resonances, at d 2279, À 443 and À 662 with relative intensities 1:4:4, respectively (DMF, 25 8C). However, the general appearance of these resonances and their coupling constants differ from those of 1.…”

“…Immediately prior to the submission of this manuscript, we learned that Schrobilgen et al had also characterized the Mo and W closo-[Sn 9 M(CO) 3 ] 4À ions, which will be described in a subsequent publication. [29] Results Synthesis: Solutions of K 4 Sn 9 in ethylenediamine (en) react with solutions of LM(CO) 3 (3) ions form dark red-brown blocks. The three complexes are very air and moisture sensitive in solution and the solid state.…”

“…The h 4 complex crystallizes preferentially (but not exclusively) from the THF/en solvent mixtures. [29] To date, all samples of crystalline [K(2,2,2-crypt)] 4 [Sn 9 W(CO) 3 ] isolated in our laboratories have been mixtures of the h 4 and h 5 isomers (solidstate IR analysis).…”

“…[32] Schrobilgen et al have characterized a different polymorph of the same cluster and will describe the details of its structure in a subsequent publication. [29] The [K(2,2,2-crypt)] 4 [Sn 9 W(CO) 3 ] ¥ 1.5 en salt is triclinic, space group P1 ≈ , and contains a disordered en solvate molecule in the crystal lattice. A summary of the crystal data is given in Table 1 and selected bond lengths and angles are given in Table 3.…”