Coordination number seven-coordinated complex

ReCl3(PPh3)(benzil)] reacts with bipy and related ligands or terpy to form a number of rhe-nium(III) and rhenium(II) compounds which are useful precursors for the synthesis of lower-valent rhenium complexes. " Thus, reduction of [Re(bipy)3][PF6]2 with zinc amalgam results in the rhenium(I) compound [Re(bipy)3][PF6] in excellent yields. The corresponding terpyridyl bis-chelate [Re(terpy)2][PF6] has been prepared in a similar manner. " The electrochemistry of the products provides a convenient measure of the chemical reactivity associated with the redox processes. Thus, the one-electron oxidation of [Re(bipy)3]" is reversible at -0.33 V, whereas the Re"/Re" redox couple is irreversible and occurs at relatively low potentials (-1-0.61 V) which is consistent with the instability of [Re(bipy)3] + in solution. However, in the presence of a small coordinating molecule such as CNBu, oxidation to the rhenium(III) state is readily available by the formation of seven-coordinate complexes of the composition [Re(bipy)3(L)]. " ... 

Complexes of 3d Metals with Coordination Number Seven and Macrocyclic 2,6-Diacetylpyridine and Some Related... 

Following Co(II) complexes, the most frequently found hepta-coordinate structures among 3d metals are those of Mn(II) complexes. Based on literature data, 21 X-ray analyses of Mn(II) complexes with coordination number seven have been reported so far. They include... 

Until several years ago, most of the known compounds of Wn were monomeric complexes, which exhibit mainly coordination number seven, and cluster compounds containing the octahedral W6 nucleus with W—W single bonds. The most important advance in the chemistry of W11 has undoubtedly been the preparation and characterization of dinuclear compounds containing W—W quadruple bonds. 

The coordination number for these complexes may be six or seven and extensive X-ray structural studies have been carried out, particularly on the seven-coordinate complexes. The geometry and some other details of a representative selection of these compounds are shown in Table 5. In some cases, e.g. [Mo(CO)2Cl2(dpam)2], one potentially chelating ligand is... 

In the solid state the stereochemistry of copper(I) in its mononuclear complexes, as determined by X-ray crystallography (Figure 4.1), is dominated by four coordination. A significant number of three- and two-coordinate complexes are known, very few five-coordinate complexes exist and six coordination (or above) is unknown. This contrasts with the predominance of six coordination in the chemistry of copper(II) (see Section 53.4.2) and the absence of two or three coordination in the solid state, and with the formation of a significant number of seven- and eight-coordinate geometries.47,48... 

A number of papers describing the synthesis and characterization of six- and seven-coordinate complexes of the types [M(CO)n(SAS)2] (M = Mo, W n = 2,3 SAS = S2CNR2, S2COEt, S2CNC4H4, S2PR2, etc.) have been published. These are not considered here because they do not contain a halo group. 

There are many complexes of lanthanides of coordination number seven [11]. There are many polyhedra for this coordination number, namely pentagonal bipyramid (Dsh) capped octahedron (C3V), tetragonal base trigonal base (Cs), capped trigonal prism (C2V) and capped trigonal prism (C3V). Inter ligand repulsivities have been studied as the function of the form of power law used for energy comparisons between different polyhedra for several coordination numbers [45,46], The order of preference for the different idealized... 

Iridium(III) complexes (d6) are diamagnetic and low-spin ((f,). The coordination number of most known iridium(III) complexes is six, though a few five- and seven-coordinate complexes have been reported. Iridium(III) forms complexes with soft ligands. The [Ir(H20)6]3+ ion is unknown no solid iridium(III) complexes with coordinated H20 groups are known with the exception of a few aquachloro complexes.197... 

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