Organotin carboxylates structure

The resulting derivatives, unlike most organotin carboxylates, are hydrolyzed relatively readily in air. An X-ray crystallographic study 399) showed that trimethyltin glycinate has an intermolecularly associated, polymeric structure, with bridging amino groups. 

A large variety of organotin carboxylates have been prepared, and their structures determined by X-ray diffraction. Part of the impetus for this work has been the search for anticancer drugs, and the aim of relating activity to structure. The early work on structure has been thoroughly reviewed,346 as well as recent developments,347 including the structural work on the organotin derivatives of amino acids and peptides.348... 

Structure, Mechanism, and Reactivity of Organotin Carboxylate Polymers... 

The organotin carboxylates may adopt a variety of structural modes depending on the nature of the organic substituent on the tin atom and/or the carboxylate... 

The tin-oxygen interatomic distances present in organotin carboxylates were classified in terms of primary Sn—O covalent bonds ca 2.0 A), slightly longer dative Sn—O bonds (ca 2.2-2.3 A) and Sn- -O secondary interactions (>2.5 A)214. Triorganotin carboxylates can adopt the three idealised structure types 124a-c. 

The development of the hypervalency concept was discussed in general. This model was concerned with the group 14 elements . The ability of the tin atom to expand the coordination sphere in organotin compounds was established in the early 1960s, when an oligomeric structure was suggested for trimethyltin fluoride and trimethyltin carboxylates" on the basis of IR data. It should be pointed out that the trimethyltin chloride-pyridine adduct was the first pentacoordinate organotin compound structurally characterized by X-ray diffraction in 1963". ... 

Organotin carboxylates and sulfonates form an important class among the family of organotin compounds.These compounds possess rich structural diversity. A range of structures from simple mononuclear compounds to complex polynuclear cages and clusters are formed." The structural diversity of these compounds emanates from several features. These include ... 

The theme of this chapter revolves around clusters of organotin carboxylates and sulfonates. For the sake of completion other structural types are mentioned briefly. 

Among organotin carboxylates, clusters and cages are formed mainly in di- and monoorganotin compounds. Among triorganotin carboxylates, the predominant structures are chain and discrete structures, although some macrocycles are also known. ... 

Organotin compounds that are salts of alkyltin oxides with carboxylic acids (e.g., dioctyltin dilaurate) are usually called organotin carboxylates. Organotin compounds with at least one tin-sulfur bond (e.g., dioctyltin octylthioglycolates) are generally called organotin mercaptides. The latter are considered to be the most efficient and most universal heat stabilizers. The important products which are on the market have the following structures ... 

The structural chemistry of organotin carboxylates has been thoroughly reviewed [419, 420] and only a brief survey of self-assembled supramolecular systems will be presented here. 

Some triorganotin carboxylate structures, in particular those containing two RsSn moieties, deserve additional comment because their structures are more varied. For example, rare types of organotin carboxylates include derivatives of carborane-carboxylic acids [ (l,7-C2BioHn-l-COO)Bu2Sn 20]2 (structure of type A) [451]. The bis(triphenyltin) derivative of phenylmaleic acid, 145, contains only four-coordinate tetrahedral tin (Sn O 2.077 and 2.090 A) and is not associated, but in the bis(triphenyltin) citraconate, 146, one tin atom participates in the supramolecular association, 147, and polymer-chain formation and becomes five-coordinate (trigonal pyramidal Sn-O 2.193 A, Sn O 2.397 A) whereas the second remains four-coordinate (Sn-O 2.089 A), as a part of a dangling side chain [441]. 

Some organotin carboxylates have structures totally different from those just discussed. For example, Bu2Sn(OOC6H4Br-2)2 is a weakly bridged dimer [497], whereas di-u-butyltin cyclobutane-dicarboxylate, Bu 2Sn(OOC)2C4H6, forms a zigzag polymer [498]. In both compounds tin is six-coordinate octahedral. 

More similar examples can be found among the structures of other nitrogen-functionalized organotin carboxylates. 

Surprisingly few organoantimony carboxylates have been structurally characterized. One might expect that further examples of self-assembly in this class of compounds will be identified if systematic structure investigation (as performed for organotin carboxylates) were to be conducted. 

Three reviews on aspects of structural chemistry were noted on organomagnesium compounds, on organotin carboxylates, and another of Melnik s systematic studies of bond parameters u g the CX3XI files, of coordination con unds of ihenium.3... 

To date, only a few papers have been published on the structures of organotin(lV) complexes formed with carboxylate compounds containing O S donor sites. 

The complexes of aromatic hydroxy carboxylic acids (salicylic acid and its isomers) with [Bu2Sn(IV)] and [Ph3Sn(IV)] were obtained. The FT-IR and Raman spectra clearly demonstrated that the organotin(IV) moieties react with the O, O) atoms of the ligands. It was found that in most cases the -COO group chelated to the central atoms, but monodentate coordination was also observed. The complexes probably have polymeric structures. 

---