Copper complexes bond lengths

Fig. 12. The variation of the copper-ligand bond-lengths in-plane (R ) and out-ofplane (Rl) for elongated octahedral copper(II) complexes (oxygen and nitrogen donor atoms only) vs. tetragonality (T)...

Thus far, we have only considered the angular geometry of complexes variations in bond lengths also pose challenges. For example, the gross inequality of bond lengths in [NiF ] and many copper(ii) and chromium(iii) complexes requires an explanation. Questions of this kind are also addressed in Chapter 7. 

TPMA ligand typically coordinates to the copper center in a tetradentate fashion, similarly to Me6TREN [117]. However, the role of counterion coordination (in particular Br and Cl ) in these complexes still remains very unclear. Recently, we were able to isolate and structurally characterize neutral CuI(TPMA)Cl [118] and CuI(TPMA)Br [119] complexes. To our surprise, both complexes were pseudopenta-coordinated (Fig. 6). In CuI(TPMA)Cl, the copper ion was coordinated by four nitrogen atoms with bond lengths of 2.0704(11), 2.0833(11), 2.0888(11) A for the equatorial Cu-N, and 2.4366(11) A for the axial Cu-N bonds, and a chlorine atom with a bond length of 2.3976(4) A. The molecular structure of Cu (TPMA)Br was similar to the structure of Cu (TPMA)Cl and the complex was also found to be pseudopentacoordinated in the solid state due to the coordination of TPMA (Cu-N... 

The carbonate group retains planarity and the three copper ions deviate from this plane by 0.05 A. The Cu-0 bond lengths in the complex are typical of five coordinate metal complexes... 

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