CHAPTER 1 Genesis and evolution in the chemistry of organogermanium, organotin and organolead compounds MIKHAIL G. VORONKOV and KLAVDIYA A. ABZAEVA A. E. Favorsky Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russia e-mail: [email protected] The task of science is to induce the future from the past Heinrich Herz I. INTRODUCTION ..................................... 2 II. ORGANOGERMANIUM COMPOUNDS ...................... 5 A. Re-flowering after Half a Century of Oblivion ................. 5 B. Organometallic Approaches to a CGe and GeGe Bond ......... 6 C. Nonorganometallic Approaches to a CGe Bond ............... 11 D. CGe Bond Cleavage. Organylhalogermanes ................. 13 E. Compounds having a GeH Bond ........................ 14 F. Organogermanium Chalcogen Derivatives .................... 17 G. Organogermanium Pnicogen Derivatives ..................... 26 H. Compounds having a Hypovalent and Hypervalent Germanium Atom .................................... 29 I. Biological Activity ................................... 32 III. ORGANOTIN COMPOUNDS ............................. 33 A. How it All Began ................................... 33 B. Direct Synthesis ..................................... 36 C. Organometallic Synthesis from Inorganic and Organic Tin Halides ... 39 D. Organotin Hydrides .................................. 41 E. Organylhalostannanes. The CSn Bond Cleavage .............. 43 The chemistry of organic germanium, tin and lead compounds —Vol.2 Edited by Z. Rappoport 2002 John Wiley & Sons, Ltd 1 2 Mikhail G. Voronkov and Klavdiya A. Abzaeva F. Compounds Containing an SnO Bond ..................... 49 G. Compounds Containing a SnE Bond (E D S, Se, N, P) .......... 55 H. Compounds Containing SnSn or SnM Bond ................ 58 I. Compounds of Nontetracoordinated Tin ..................... 62 J. Biological Activity ................................... 65 K. Practical Use ....................................... 66 IV. ORGANOLEAD COMPOUNDS ............................ 67 A. Introduction ....................................... 67 B. Synthesis from Metallic Lead and its Alloys .................. 68 C. Metallorganic Approaches to Organolead Compounds ............ 68 D. Nonorganometallic Approaches to the Formation of a CPb Bond ... 71 E. Cleavage of the CPb and PbPb Bond .................... 72 F. Compounds having a PbO Bond ......................... 78 G. Compounds having a PbS, PbSe and PbTe Bond ........... 84 H. Compounds having a PbN Bond ......................... 85 I. Organolead Hydrides ................................. 87 J. Compounds Containing a PbPb Bond ..................... 89 K. Biological Activity and Application of Organolead Compounds ..... 95 V. CONCLUSION ....................................... 97 VI. REFERENCES ........................................ 98 I. INTRODUCTION Germanium, tin and lead are members of one family, called the silicon subgroup. Some- times these elements are called mesoids as well, due both to their central position in the short version of Mendeleev’s Periodic Table and to their valence shells, which occupy an intermediate place among the I–VII Group elements1. They can also be called the heavy elements of Group 14 of the Periodic Table. The history of the silicon prototype of this family and its organic derivatives is eluci- dated in detail in the literature2–5. In contrast, we could not find any special accounts dealing with the history of organic germanium, tin and lead compounds. The only excep- tion is a very brief sketch on the early history of the chemistry of organotin compounds6. Some scattered information on the organic compounds of germanium, tin and lead can be found in some monographs and surveys. In this chapter we try to fill the gaps in this field. Humanity first encountered the heavy elements of Group 14 at different times; with germanium, it happened quite unusually in the middle of the 19th century. As with the discovery of the planet Neptune7, which was first predicted by astronomers and almost immediately discovered, Mendeleev, who predicted the existence of three hither to unknown elements, reported at the Russian Chemical Society session on December 10, 1870 on the discovery of one of these elements as follows: ‘...to my mind, the most inter- esting among undoubtedly missing metals will be one that belongs to Group IV and the third row of the Periodic Table, an analog of carbon. It will be a metal, following silicon, sowecallit‘eca-silicon’8. Moreover, Mendeleev even predicted the physical and chem- ical properties of the virtual element9–12. Having no conclusive proof of the existence of eca-silicon, Mendeleev himself began experimental investigations aimed at finding it in different minerals13. It is noteworthy that as early as 1864 Newlands14 and Meyer15 suggested the possible existence of an element like eca-silicon and predicted its atomic weight. However, Mendeleev was the first to predict properties of the element in detail. Fifteen years later the German chemist Winkler16,17, working at the Freiberg Academy of Mines, was able to isolate during the investigation of a recently discovered min- eral argirodit (Ag6GeS5) a new element in its free state. Initially, Winkler wanted to 1. Genesis and evolution in the organic chemistry of Ge, Sn, and Pb compounds 3 name the new element neptunium, after the newly discovered planet Neptune. However, this name seemed to be given for another falsely discovered element, so he called the new element germanium in honor of his motherland18–21. At the time several scien- tists sharply objected to this name. For example, one of them indicated that the name sounded like that of the flower Geranium while another proposed for fun to call the new element Angularium, i.e. angular (causing debates). Nevertheless, in a letter to Win- kler, Mendeleev encouraged the use of the name germanium. It took same time until the identity of eca-silicon and germanium was established18–22. Polemics, as to which element germanium is analogous flared up ardently. At first, Winkler thought that the newly discovered element filled the gap between antimony and bismuth. Having learned about Winkler’s discovery, almost simultaneously in 1886 Richter (on February 25, 1886) and Meyer (on February 27, 1886) wrote him that the discovered element appeared to be eca-silicon. Mendeleev first suggested that germanium is eca-cadmium, the analog of cadmium. He was surprised by the origin of the new element, since he thought that eca- silicon would be found in titanium–zirconium ores. However, very soon, he rejected his own suggestion and on March 2, 1886, he wired Winkler about the identity of germanium and eca-silicon. Apparently, this information raised doubts in Winkler’s mind about the position of germanium in the Periodic Table. In his reply to Mendeleev’s congratulation he wrote: ‘...at first I was of the opinion that the element had to fill up the gap between antimony and bismuth and coincide with eca-stibium in accordance with your wonderful, perfectly developed Periodic Table. Nevertheless, everything showed us we dealt with a perfectly well developed Periodic Table. But everything implied that we are dealing with eca-silicon23. The letter was read at the Russian Physical and Chemical Society section on March 7. Winkler reported that the properties of the element and its common derivatives corresponded closely to those predicted for eca-silicon. A second letter by Winkler was read in a Chemical Section meeting of the Russian Physical and Chemi- cal Society on May 1,1886. Winkler reported that the properties of germanium and its simpler derivatives were surprisingly very similar to those predicted for eca-silicon22,24. This is reported in Winkler’s paper in the Journal of the Russian Physical and Chemi- cal Society entitled ‘New metalloid Germanium’, translated into Russian at the author’s request25,26. An inspection of Table 1 impresses one by the precise way in which Mendeleev pre- dicted the properties of germanium and its elementary derivatives. In 1966, Rochow27 somewhat criticized the accuracy of Mendeleev’s predictions of the properties of eca-silicon (germanium). He stated: ‘Mendeleev predicted that eca-silicon would decompose steam with difficulty, whereas germanium does not decompose it at TABLE 1. The properties of eca-silicon (Es) and its derivatives predicted by Mendeleev9– 12,19,20 in com- parison with the properties of germanium and several germanium derivatives24– 30 Properties M D Es M D Ge Atomic weight 72.0 72.3 Specific weight 5.5 5.469 Atomic volume 13.0 13.2 Specific weight of MO2 4.7 4.703 ° ° B.p. of MCl4 ca 90 88 Specific weight of MCl4 1.9 1.887 ° ° B.p. of M(C2H5)4 ca 160 160 Specific weight of M(C2H5)4 0.96 1.0 4 Mikhail G. Voronkov and Klavdiya A. Abzaeva all. This is to say that germanium is less metallic than was predicted. Mendeleev also said that acids would have a slight action on the element, but they have none; again it is a more negative element than was predicted. There are many more chemical facts31 which point in the same direction: germanium is more electronegative than was expected by interpolation, and it actually behaves a great deal like arsenic’. Rochow was right to some extent. It is known32,33 that in accordance with Mendeleev’s predictions germanium has more metallic characteristics than silicon; in a thin layer or under high temperatures germanium reacts with steam, and it reacts very slowly with concentrated H2SO4, HNO3, HF and Aqua Regia.