Anionic dicarbollyl complexes of germanium(II) and tin(II) — missing links in a series of π-complexes with Group 14 elements as central atoms
✍ Scribed by Peter Jutzi; Dirk Wegener; Hans-Georg Stammler; Alexander Karaulov; Michael B. Hursthouse
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 799 KB
- Volume
- 198-200
- Category
- Article
- ISSN
- 0020-1693
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✦ Synopsis
On the basis of the isolobal concept, comparable series of structurally different rr-complexes with Group 14 elements as central atoms and with cyclopentadienyl or dicarbollyl systems as ligands can be organized. We describe for the first time anionic rr-complexes in which one or two dicarbollyl (B,H,&Mq) ligands are coordinated to a divalent germanium or tin centre. Thus, reaction of the phosphonium salt Ph,MeP+TlB&,GMe,-(4) with the element dichlorides GeCl, and SnC12, respectively, in a 1:l ratio leads to the ionic compounds Ph,MeP'ClGeB&~Me,-(5) and Ph,MeP+ClSnB&&Me,-(6), respectively. In a 2:l ratio of the same reactants, the ionic compounds (PhJMeP+)zGe(B,HgQMe2)22-(7) and (Ph,MeP+)2Sn(B,H,&Me2)22-(S), respectively, are formed. Some further chemistry of the starting material Tl+TlB,H,&Me,-is also described. The characterization of the new complexes is based on 'H, 13C, rlB and "'Sn NMR data and on X-ray crystal structure investigations (5 and 7). *Fenske-Hall and MNDO-SCF molecular orbital calculations show that cyclopentadienide and dicarbollide r-systems are not isolobal in a strong sense [7]. **Nearly all r)s-complexes show a distinct dislocation of the apical heteroatom away from the two cage carbon atoms. Calculations [7] have been used to explain the slip distortion.