Benzenoid-metal complexes

For a monograph, see Zeiss, H. Wheatley, P.J. Winkler, H.J.S. Benzenoid-Metal Complexes Ronald Press NY, 1966. 

Zeiss, H., Wheatley, P. J., Winkler, H. J. S. Benzenoid-metal complexes, New York Ronald Press 1966. 

For a monograph, sec Zeiss Wheatley Winkler Benzenoid-Metal Complexes Ronald Press New York. 1966. 

H. H. Zeiss, P. J. Wheatley and H. J. S. Winkler, Benzenoid-Metal Complexes , Ronald Press, New York, 1966. 

Most of the neutral DA crystals have been prepared from an uncharge transition-metal complex and a benzenoid or quinoid organic acceptor. One class of these donors involves the complex [M(qnl)2], where M = Cu or Pd24 32). There is one example where a metal-containing subunit acts as the acceptor M(tfd)2 reacts with the organic donors perylene and pyrene to afford a complex with neutral DA stacks33,34. ... 

S. Rosea Stud. Cercet. Chim. 17, 613 (1969) Benzenoid-metal aromatic 77-complexes 24 (78) Rom. 

In 1970, the synthesis of the orange-red sandwich cation 1 from cobaltocene and PhBCl2 (1) marked a further starting point in the chemistry of boron metal compounds. The presence of a planar benzenoid C5H5B ligand moiety in 1 was deduced from XH and UB NMR data (1). This was made ironclad by two X-ray structure determinations which revealed typical centrosymmetric sandwich structures for the 19-e complexes Co(C5H5BOMe)2 (6) (21,22) and Co(C5H5BMe)2 (7) (22) as shown in Fig. 1. 

Nitro dyes exhibit benzenoid-quinonoid tautomerism (1.25) and their colour is attributed mainly to the o-quinonoid form, since this can be stabilised by hydrogen bonding. The tautomeric o-nitrosonaphthols (1.26) readily form chelate complexes with metals. A few yellow nitro disperse dyes, including Cl Disperse Yellow 1 (1.25), and brown acid dyes remain of significance. The remaining nitro and nitroso colorants, such as (1.26) and its 1 3 iron (II) complex (1.27), are no longer of commercial interest. 

The protonation studies are of interest in another connection. If protonation of metallocenes can be considered to be a simple form of electrophilic attack, it is possible that other types of electrophilic substitution reactions may proceed through initial coordination of the electrophile with the central metal atom (14, 93). The mechanism of acylation of metallocenes may therefore be more complex than might be expected by analogy to similar reactions of benzenoid compounds. Clearly more studies are needed along these lines, better to define specific metal effects on the properties and reactions of these remarkable compounds. 

Figure 8.1 illustrates the structure of a series of metallized azo reds that are of considerable commercial importance and that some use within the plastics industry. Each structure features a molecule based on the coupling of a naphthalene ring structure to a benzenoid structure. Further each molecule contains at least one anionic group, namely sulfonic acid, S03H—, capable of complexing with a metal cation. A brief description each of the more common metallized azo reds follows. 

Selective transport of Hg(II) over Cu(II) through chloroform from a solution of these metal ions to an aqueous HCl solution was demonstrated for the troponoid dithiocrown ether (19). The benzenoid dithiocrown ether (20) was a much less effective transporter in spite of similar cavity size, suggesting protonation of the tropone ring assisted release of the Hg(II) from the complex. 

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