Halides of the Heavier Group 14 Homologues Germanium, Tin, and Lead—A Journey through Unusual Compounds and Oxidation States

Abstract

Classical halides of the heavier Group 14 homologues germanium, tin, and lead are common precursors for the synthesis of exciting compounds, such as polyhedral clusters. To get access to larger metalloid cluster compounds of Group 14, the disproportionation reaction of metastable monohalide solutions, accessible through a preparative co‐condensation reaction, proved to be quite successful. As the identity of the subvalent halides within the metastable solutions were yet unknown the reaction course from a monohalide precursor to a metalloid cluster was mostly unidentified. This might change now, as a first subhalide cluster [Ge14Br8(Et3P)4] could be characterized, being the first trapped intermediate of the disproportionation reaction of Group 14 subhalides. All these aspects are included within this Minireview, together with a short historical overview, dealing with the development of the preparative co‐condensation technique out of the matrix isolation technique, being the essential first step of the synthesis of metastable monohalide solutions of the heavier Group 14 elements Ge and Sn.

Reactions of GeCl2 with the Thiolate LiSC(SiMe3)3: From thf Activation to Insertion of GeCl2 Molecules into C−S Bonds

“…Scheme5.Synthesis of [ClGeSTsi] 2 (5). ;C l1-Ge1-S1 95.65(10), Ge1-S1-C1 116.3(3), Ge1-S1-Ge1' 91.79(9), S1-Ge1-S1' 78.81 (8);G e1-S1-Ge1'-S1' 33.031 (8).…”

“…[7] To synthesizeg ermylenes, the GeCl 2 ·dioxane complex is widely used as ap recursorf or substitution reactions. [8] In addition, GeCl 2 can undergo oxidative insertion reactions into different kinds of bonds. In this respect, Filippoua nd co-workers and then Schmidbaur andc o-workerss howed that GeCl 2 can insert into metal-chlorine and metal-hydrogen bonds of transition-metal complexes to give [CpR 5 M(CO) 3 GeCl 3 ]( M = Mo, W; R = H, Me), [Au 2 (Ph 2 P(CH 2 ) n PPh 2 ) 2 ][Au(GeCl 3 ) 2 ] 2 (n = 1, 2), and CpMo(-CO) 3 GeCl 2 H. [9] An insertion of GeCl 2 into the GeÀCl bond of the Ge II adduct IPrGeCl 2 (IPr = [(HCNDipp) 2 C:]; Dipp = 2,6-iPr 2 C 6 H 3 ) to form new GeÀGe bonds is also possible, as was shown by Rivard and co-workers.…”

“…In 2013, Power and co‐workers presented a number of stable acyclic, monomeric tetrylene dichalcogenates of the formula M(ChAr) 2 (M=Si, Ge, Sn, Pb; Ch=O, S, Se, Ar=bulky m ‐terphenyl ligand), which display acute interligand bond angles . To synthesize germylenes, the GeCl 2 ⋅dioxane complex is widely used as a precursor for substitution reactions . In addition, GeCl 2 can undergo oxidative insertion reactions into different kinds of bonds.…”

On the instability of iodides of heavy main group atoms in their higher oxidation state

“…Why does Pb form stable tetravalent compounds with organic substituents but not with inorganic ones? 1 This question was addressed by Prof. Schleyer and Prof. Martin Kaupp in 1993. 2 They proposed that electronegative substituents tend to destabilize the bonds in tetravalent Pb.…”

On the Instability of Iodides of Heavy Main Group Atoms in their Higher Oxidation State

“…Why Pb forms stable tetravalent compounds with organic substituents but not with inorganic? 1 This question was addressed by Prof. Schleyer and Prof. Martin Kaupp in 1993. 2 They proposed that the electronegative substituents tend to destabilize the bonds in tetravalent Pb.…”