Coordination chemistry mononuclear complexes

The complex coordination chemistry of Pb" is also beginning to be actively explored and some unusual stereochemistries are emerging. Thus, the mononuclear ( ) -nitrato)bis(phenanthrolene)(A-thiocyanato) complex [Pb(phen)2(NCS)( ) -NO3)] has 7-coordinate Pb" with a large vacancy... 

The coordination chemistry of tertiary phosphine-functionalized calix[4]arenes have been described.279 Treatment of a bis(diphenylphosphino) or bis(dimethylphosphino) derivative of calix[4]arene with [PtCl2(COD)] leads to the formation of the corresponding dichloroplatinum(II) complex. The related diplatinum(II) species has also been reported with the tetrafunctionalized calix[4]arene.280 The mononuclear derivative is susceptible to oligomerization if the two free phosphine ligands are not oxidized or complexed to another metal center such as gold(I).279 The platinum(II) coordination chemistry of a mono-281 and diphosphite282 derived calix[ ]arene (n = 4 and 6, respectively) has also been described. 

Mononuclear examples are dominant in the simple coordination chemistry of molybdenum(VI). This is due in part to the absence of d electrons in Movl complexes, which precludes the formation of MoVI—Mo 1 metal-metal bonds. However, note must be taken of the very large class of homo- and hetero-polymolybdates which contain polynuclear Mo. These... 

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... 

Solvated transition metal cations containing weakly bonded organic ligands are potentially useful as intermediates in preparative coordination chemistry. The coordinated solvent molecules provide solubility of the compounds in various organic solvents, and they can be replaced readily by other ligands with better donor properties.1, 2 The preparation of mononuclear transition metal complexes with weakly bonded anions has been described previously3 and preparative applications of such complexes have been reviewed.4... 

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