An approach to creating novel anions: silylated triel compounds with -CH₂- and -O- linkers, [InCl₂{O(HO)Si(t-Bu)₂}]₂ and Li[B(CH₂SiMe₃)₄]

Bis­[[mu]-di-tert-butyl­(hy­droxy)­silanol­ato]­bis­[chlorido­indium(III)], [In₂(C₈H₁₉O₂Si)₂Cl₄], (I), is a centrosymmetric two-centre indium complex featuring a system of three annulated four-membered rings; the structure is the first example of an In₂O₂ ring which is annulated with two Si-O units to form a ring system composed of three rings. The coordination environment of the In centres is a distorted trigonal bipyramid. The crystal packing of (I) is characterized by chains of mol­ecules connected by O-H...Cl hydrogen bonds. The crystal of (I) was a nonmerohedral twin. There is no known example of an In₂O₂ ring in which the In atoms carry any two halogen ligands. The structure of tetra­kis­(tetra­hydro­furan)­lithium tetra­kis­[(tri­methyl­silyl)­methyl]­borate, [Li(C₄H₈O)₄](C₁₆H₄₄BSi₄), (II), is composed of discrete cations and anions. The coordination geometries of the Li and B centres is tetra­hedral. The cations and anions lie in planes parallel to the ab plane. There are no short contacts between the cations and anions. Compound (II) is the first example of a B centre bonded to four -CH₂Si units.