Clusters zigzag chains

Fig. 5.7 View of the inter-cluster connectivity in the [(Zr6B)Clii xl2+x] structure c and the zigzag chains run horizontally). The Zr-Zr bonds are emphasized, and the inner halides are omitted for clarity.

Fig. 6.7 (a) Perspective of Ti2Nb5Cli404 structure in the [001] direction, (b) Cluster layer in Ti2Nb6Cli404. (c) Zigzag chain of edge-sharing [TiCl402] octahedra in Ti2Nb6Cli404. 

The only non-octahedral hexanuclear cluster units are six-membered ring Rh6 (chair conformation, Figure 3), and open, non-planar zigzag chain Zr6, which are found respectively in Rh3S4 and Zr3Te (Rh-Rh 2.70 and 2.87 A Zr-Zr 3.01-3.15 A). In addition there are strong transannular interactions in the Rh6 ring (3.09 A), and weak contacts between the Zr6 chains.96,97... 

As may be seen from inspection of Eqs. (5) and (6) the two / A(amino)carbene analogues react differently with lCp(CO)2Fe]2. While only one germylene inserts into the iron-iron bond forming 12, two stannylene units are inserted to form 13. In the first case a triatomic heterometal cluster is obtained with an electron count similar to that in compounds 10 and 11 and in the second case (Eq. 6) a tetra-atomic Fe-Sn-Sn-Fe zigzag chain with point symmetry Cj is obtained with Sn-Fe distances of 2.605(2) A and a Sn-Sn bond length of 2.991(2) A the Fe-Sn-Sn angle is 117.9(1)°. In contrast to compound 9, the Sn-N distances are not shortened in 13 and are found to be almost equal to that in the free stannylene (13 Sn-N 2.099(2) A). 

Figure 8.7. Plots of AE (n) and AE (n) versus Ijn for zigzag chains and for cyclic hydrogen fluoride clusters as obtained at the MP2/6-311+ +G(2d,p) level [52]. Open symbols A (n) filled symbols AE (n) circles cyclic structures squares chains.

Figure 8.8. Trends in intramolecular F—H and intermolecular F---F distances in zigzag chain-like (HF) clusters as obtained at the MP2/6-311G-I-- -(2d,p) level [52]. Distances belonging to the same oligomer are marked by identical symbols and connected by lines.

Finally, it is worthwhile to mention that a very similar interconnection of (empty ) clusters is found in the structure of BaMogOjo (Lii et al. 1988) which contains discrete MogOi2 clusters linked via intercluster metal-metal bonds into zigzag chains. 

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