Organotin compounds coordination chemistry

Since the dominant higher-coordination chemistry is that of tin, we survey this first. The range of structural studies is so wide that it is possible only to generalize and look at recent and representative examples. Intramolecular coordination in organotin compounds has been extensively reviewed up to 1992113. 

In contrast to the extensively studied doubly bonded systems of silicon and germanium, the chemistry of the corresponding tin compounds, i.e. distannenes and stannenes, has not been fully disclosed yet probably due to the much higher reactivity and instability of such low-coordinated organotin compounds. In the following sections we briefly describe the synthesis and properties of stable distannenes and stannenes. 

In 1951, Solerio reported that compounds with the R2SnO formula could be monomeric as well, when the tin atom carries bulky substituents, such as diorganylstannanones R2Sn=0, R = C12H25. When the substituents R are less bulky, the substrates are still polymers. Thus, Solerio can be considered as the founder of the chemistry of diorganylstannanones R2Sn=0, the first organotin compounds of three-coordinated tin, bonded to one of its substiments by a double bond. 

Hypervalent compounds are common in the case of lead, rather than the tetrahedral ones ". However, the coordination chemistry of hypervalent lead compounds has been much less studied than that of hypervalent organotin compounds, probably due to the well-known high toxicity of organolead derivatives. The progressive lowering of the three-center interaction for the group 14 column of the Periodic Table and the marked drop for lead can be accounted for in terms of the relativistic effect. ... 

Two-dimensional H- Sn Proton Detected Correlation Spectroscopy in Coordination Chemistry of Hypervalent Organotin Compounds... 

Little has been reported yet on the coordination chemistry of mono-organotin compounds. Coordination numbers of five to eight for the tin atom have been reported in such compounds (39,50,51). It has been suggested, however, that in solution a trigonal bipyramidal arrangement at tin is the most favorable one (49). 

The coordination chemistry of divalent organotin compounds is a special case, since the tin atom can act both as an acceptor and as a donor, e.g., as in (CO)3CrSn(f-Bu)2 pyridine (52). 

Organotin compounds with Sn-S bonds can be prepared by substituation at tin by sulfur nucleophile. There are many parallels between the chemistry of compounds containing Sn-S bonds and those containing Sn-0 bonds. An important difference between them is that whereas Sn-0 bonded compounds often self-associate to give oligomers or polymers with 5-coordinate tin, the sulfur compounds show fewer tendencies to associate. The Sn-S bonds also less easily cleaved in substitution (e. g. hydrolysis) and addition reactions [54,56]. 

As part of an ongoing study of dithiolate complexes of main group elements and of the coordination chemistry of tin(lV) compound, we now report the results of synthesis and structural investigation of several organotin complexes with a series of aminodithiocarboxylate ligands in solution and solid state. 

Kayser F, Biesemans M, Gielen M and Willem R (1996) Two dimensional H- Sn proton detected correlation spectroscopy in coordination chemistry of hypervalent organotin compounds. In Gielen M, Willem R and Wrackmeyer B (eds), Advanced Applications of NMR to Organometallic Chemistry, pp 45-86. Chichester Wiley. 

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