Macrocyclic complexes dithiocarbamates

There have been two books that contain compilations of the electrochemistry of Os (572,573). There have also been reviews that cover the electrochemistry of certain classes of complexes with ligands such as porphyrins (142), dithiocarbamates (463), and macrocyclic complexes (39, 93). The purpose of this section is not to provide a comprehensive review of electrochemical studies over recent years, but rather to give some insight into the factors that affect the redox potentials and their use in obtaining information about 7r bonding and backbonding. Particular emphasis is placed on the similarities and differences between analogous Os and Ru complexes. 

Oxidation of Co111 dithiocarbamates gives [Co(dtc)3]+ complexes which are low-spin d5 with magnetic moments between 2.2 and 2.7 BM. For the macrocyclic complex (17-F-IX) (formally CoIV) square geometry was confirmed by X-ray diffraction the compound has one unpaired electron and slowly oxidizes water, with reduction to H[Com(L)].M... 

Many dithiocarbamate complexes of zinc, silver, cadmium or mercury improve emulsion stability, including bis(dibenzyldithiocarbamato)-zinc(II) or -cadmium(II) and silver(I) diethyldi-thiocarbamate. Cadmium salts, mixed with citric acid or tartaric acid and added to the emulsion, are reported to be effective. Mercury(II) complexes of ethylenediaminetetraacetic acid (EDTA) and related ligands and of solubilized thiols such as (4) can be used. Other coordination compounds reported include EDTA and related ligand complexes of Co and Mn, mixtures of Co salts with penicillamine (5) and macrocyclic complexes of Ag such as (6). The latter compounds may be used in diffusion transfer systems in which transferred maximum densities are stabilized. 

A number of dithiocarbamates derived from diamines have been prepared, including those based on a terphenyl backbone, which have utilized these ligands toward the self-assembly of large metal-containing macrocycles upon addition of metal acetates (1468,1469). For example, macrocyclic complexes (347) have been prepared in this manner. 

Recently, Beer et al. (62) prepared the novel nickel(IV) complex 371, in which two metal centers are linked via three bis(dithiocarbamate) ligands, upon oxidation of the related macrocyclic complex 370 by 7/-bromosuccinimide (NBS) (Fig. 197). The nickel(IV) dication 371 binds both chloride and nitrate anions as shown by cathodic shifts of the Ni(IV)/Ni(III) wave of 70 and 15 mV, respectively. 

In an exciting development. Beer and co-workers prepared a range of novel compounds incorporating copper(ll) bis(dithiocarbamate) units (Fig. 220). These include macrocyclic complexes based on terphenyl diamines (439-442) (326, 1468, 1469) and ferrocenyl amines (443) (1468), pyrrole-based metallo-cryptands (444) (492), cyclic amide complexes (445), and monometallic complexes with crown-ether substituents (446) (492), a number of which have been... 

Coordinated transition metal redox-active macrocycles, 39 108-124 ammonium cation, 39 128-133 crown ether and bis crown ether ligands containing bipyridyl transition metal recognition sites, 39 111 crown ether dithiocarbamate and dithiolene complexes, 39 123-124 metalloporphyrin crown ether compounds, 39 108-109... 

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