Organotin Activities

there is legislation that prohibits use of monomeric organotin compounds for many applications, thus there is an increased emphasis on the synthesis and application of bound organotin compounds (i.e., organotin moieties that are part of a polymer). The polymer can be part of the polymer backbone or as an appendage draping from the polymer backbone. 

We have been involved in the synthesis and characterization of organotin polymers for over 30 years. The synthesis of organotin polymers was recently reviewed [2]. Much of our interest in organotin polymers is related to their antibacterial, anticancer, and antiviral activity [2-32], The antibacterial and anticancer activity of these polymers has been recently reviewed [2,3]. 

The general toxicity of organotins seems to follow no general rules. Toxic effects are often highly species-specific [36,37] (Table 17.1). 

Little is known about the effects of organotins in humans. There are no epidemiological smdies available on the chronic low-level exposure. However, some case reports have described various health effects after acute exposure to tributyltin and triphenyltin conpounds. The patients developed acute nephropathy and mainly CNS disorders [45 7]. Some reports described the neurotoxicity of trimethyltin, triethyltin, and triphenyltin compounds in humans [48,49]. There are even some reports about cases of tributyltin, triphenyltin, and TBTO induced tumors [50-52]. However, the precise mechanism of tumor induction is not known. 

The polymers studied here have inhibited a wide variety of bacteria, fungi, and yeast. The following is a list of agents successfully inhibited by the compunds discussed in this chapter [2]. 

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Photoresists. Three-dimensional relief images which can function as photoresists for circuit board fabrication were demonstrated using organotin activators (65). 

Here we will look at some findings that highhght potential modes of activity as well as problems associated with looking at organotin activity. Further, essentially no mechanistic studies have been carried out on tin polymers, so results from studies of small molecule-containing organotin agents will be examined. 

In the direct coupling reaction (Scheme 30), it is presumed that a coordinatively unsaturated 14-electron palladium(o) complex such as bis(triphenylphosphine)palladium(o) serves as the catalytically active species. An oxidative addition of the organic electrophile, RX, to the palladium catalyst generates a 16-electron palladium(n) complex A, which then participates in a transmetalation with the organotin reagent (see A—>B). After facile trans- cis isomerization (see B— C), a reductive elimination releases the primary organic product D and regenerates the catalytically active palladium ) complex. 

Equilibrium, Structural and Biological Activity Studies on [Organotin(IV)]" Complexes... 

Organotin(rV) compounds are characterized by the presence of at least one covalent C-Sn bond. The compounds contain tetravalent Sn centers and are classified as mono-, di-, tri-, and tetraorganotin(IV), depending on the number of alkyl (R) or aryl (Ar) moieties bound. The anions are usually CP, F , 0 , OH , -COO , or -S . It seems that the nature of the anionic group has only secondary importance in biological activity. 

The aim of the present work is to survey the results obtained by means of different equilibrium and structural measurements on the complexes formed with the various organotin(IV) cations. The biological activities of parent organotin(IV) and some of the complexes in object are also discussed. In the rest of the chapter, complexes of the organotin(IV) cations will be discussed — in most cases — in the following order ... 

The most widely studied interactions between biologically active ligands and organotin(lV) cations relate to the amino acids and their derivatives (N- or S-protected amino acids and peptides), though new data on several of the most commonly occurring amino acids are still being published. This is specially true for aqueous speciation studies. Nice and very detailed reviews were published in this area by Molloy and Nath. ... 

In contrast to this view, but in analogy with the behavior of several antitumor metal complexes, some authors proposed that the DNA is the probable target for cytotoxic activity of organotin(IV) compounds. In this section we survey and compare the most important literature data published to date on this subject. 

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