ISSN:
1572-901X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Summary The complexes [MoL*(NO)Cl(YC6H4YH-m)] (Y = O or NH), [MoL*(NO)Cl(YC10H6YH-1,5)], (Y = O or NH), [MoL*(NO)Cl(OC10H6OH-2,7)], [{MoL*(NO)Cl}2(XC6H4Y-m)] (X=Y=O, NH or S; X=O, Y=NH), [{MoL*(NO)-C1}2(YC10H6Y-1,5)] (Y=O or NH) and [{MoL*(NO)Cl2-(OC10H6-2,7)] have been prepared and studied by cyclic voltammetry. The monometallic species undergo a reversible oneelectron reduction, whereas the bimetallics undergo two oneelectron reductions. A comparison of ΔE1/2 (E1/2(1)-E1/2(2)) values for those new species with those obtained frompara- substituted analogues and bimetallics containing extended bridges YC6H4ZC6H4Y (e.g. Z = S or CH2CH2) established that the interaction between the redox centres in these new species is intermediate (YC6H4Y-m; NHC10H6NH-1,5) or weak (OC10H6O). In earlier papers1,2 we have described the synthesis and electrochemical properties of a series of mono- and bi-metallic complexes of the type [MoL*(NO)X(YC6H4YH)], [MoL*(NO)X}2(YC6H4Y)] and [{MoL*(NO)X}2(YC6H4-ZC6H4Y)] [L*=tris(3,5-dimethylpyrazolyl)borate, HB(Me2C3HN2)3] where the arene ring ispara-substituted (X=Cl or I while Y=O, S or NH and Z = nothing, CH2, CH2CH2, S, SO2 or O). We have shown that the E1/2-values of these species are dependent on X and Y, and that the bimetallic species undergo two one-electron reduction processes. We have established that there is strong interaction between the redox centres in bimetallics bridged byp-YC6H4Y, but that weak-to-negligible interaction occurs in those species containing YC6H4ZC6H4Y bridges. In this paper we describe our investigations ofmete-substituted bridging systems,m-YC6H4Y, and comparable systems containing naphthalene bridges,e.g. 1,5- or 2,7-YC10H2Y. From these studies we hoped to establish the extent of interaction between the two redox centres and how this compared to thepara-substituted arene counterparts.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00621516
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