Anionic structures structural analysis

Surprisingly, X-ray structural analysis of the dark-green, hygroscopic tetrabutylam-monium salt of 5//-dibenz[6,/]azepine reveals that the potentially antiaromatic 5//-dibenz-azepine anion has a less pronounced nonplanar butterfly structure (161° vs. 144 ) than 5H-dibenz[6,/]azepine.243... 

Attempts to prepare related hpp complexes of tantalum were only partially successful. Reaction of 2 equivalents of either (hpplSiMes or in situ generated Li[hpp] with Tads afforded a solid that analyzed correctly for the compound (hpp)2TaCl3. X-ray structural analysis of the crystallized product identified the coordination isomer [Ta(hpp)4][TaCl6], with a distorted dodecahedral cation and a regular octahedral anion (Figure 28). °... 

The cis configuration of 96 was elucidated by X-ray structure analysis. The data suggest that the cyclization reaction of the anion 95 generated from 94 to 91a proceeds stereoselectively in the solid state [16]. 

Structure analysis of 61 [MgBrCthf) ] revealed a Pba trigonal-pyramidal configuration of the molecule with the electron pair occupying the apex position, resulting in the large pyramidalization at the central anionic Pb atom (279°). 

The (EDT-TTF-I)2Br salt described above [36] and the 1 1 (TTFI4)I salt reported by Gompper [51] were the only structurally characterized salts with simple halide anions until Imakubo recently described an extensive series of Cl" and Br" salts from several ortho-diiodo tetrathiafulvalene, tetraselena-fulvalene and dithiadiselenafulvalene derivatives (Scheme 8) [62], The X-ray crystal structure analysis of the nine salts described there show a variety of halogen bonded motifs, demonstrating the adaptability of the supramolecu-lar interactions to other structural requirements imposed by the nature of the heteroatoms (O, S, Se) in the TTF frame. Indeed, in (EDT-TTF-l2)2X-(H20)2 (X = Cl, Br), a bimolecular motif (Fig. 6) associates two partially oxidized EDT-TTF-I2 molecules with one Br" anion and one water molecule. 

The cluster anion, [Os3Ir(CO)i3], was prepared in 50% yield by reaction of Os3(CO)i2 with [Ir(CO)4]. The single-crystal X-ray structure analysis shows it to consist of a tetrahedral metal core with one of the 13 carbonyl ligands bridging. The catalytic activity for carbonylation of... 

The first derivative of carba-nido-tetraboranes(7), 16a, was prepared by reaction of anionic 17 with iodomethane and characterized by NMR spectroscopy and by model computations (Scheme 3.2-10) [28]. The structurally analyzed 16b is obtained by deuteration of the dianion 10a2 [20] mentioned in Section 3.2.2.2. The results of an X-ray structural analysis of its dilithium salt are discussed in Section 3.2.8.3. The lithium cations are coordinated side-on to the B-B 2c2e bonds just as predicted for the aromatic U2B3H3 [6]. Obviously, (Li+)210a2 is a 2e homoaromatic. Since the positions of the lithium cations resemble those of the deuter-... 

A positive evidence for a true cr-bonded organolanthanide complex is presented by Cotton et at. (32) in a crystal structure analysis of the anionic complex [Lu(III)-tetrakis-2,6-dimethylphenyl] . This anion crystaJUizes as [Li(I)-tetrakis-tetra-hydrofuran]+ salt, [Li(C4HgO)4]+ [Lu(C8H9)4] , in orthorhombic space group (P2i2i2i) with a = 15.093, 6 = 15.265 and c = 19.959 A and four formula units per unit cell. 

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