Unusual chalcogen-boron ring compounds: the gas-phase structures of 1,4-B4S2(NMe2)4 and related molecules

Abstract

The structure of 1,4-B 4 S 2 (NMe 2 ) 4 has been determined by gas-phase electron diffraction and quantum chemical calculations and is compared with the known solid-state structure. While these structures are similar, with a twisted ring geometry [the dihedral angle S-B-B-S from electron diffraction is 75.4 (16) • ], they are strikingly different to the solid-state structure of 1,4-B 4 O 2 (OH) 4 , which is planar.

Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse

“…The Lewis acid binds to the N atom on the backbone of the diboron compound, with both mono- and diadducts of the diamino compound observed, depending on the equivalents of EX 3 used. Furthermore, it is noteworthy that B 2 (NMe 2 ) 4 also reacted with H 2 S to form heterocycles containing B 2 (NMe 2 ) 2 fragments bridged by two sulfur atoms. , An interesting use for these compounds was investigated by Patton and co-workers, who discovered a novel synthetic pathway to various diboron-bridged bis­(amide)–base complexes, starting from tetrakis­(dimethylamino)­diboron(4) (Scheme ). This was initially reacted with HCl to form the mixed diamino–dichloro diboron compound, before reaction with the respective lithium anilinide to form the predicted diboron(4).…”

Oxygen, sulfur, selenium, tellurium and polonium

“…The amido-substituted heterocycle 1,4-B 4 S 2 (NMe 2 ) 4 has been shown to adopt a twisted ring geometry in both the solid state and gas phases [t S-B-B-S = 66.61 (solid), t S-B-B-S = 75.4(16)1 (gas)], in contrast to the oxygen analogue which is planar in both the solid and gas phases. 39 Group 16 donor ligands have been used to coordinate to a range of hard and soft Group 13 metals; 4,5-(P(E)Ph 2 ) 2 tzH (E = O, S, Se) exhibits a versatile range of coordination geometries (k 2 -O,O-k 2 -N,S-and k 2 -N,Se-) with AlR 2 (R = Me, i Bu) 40 and the soft donor RECH 2 CH 2 ER (RE = MeS, MeSe, n BuSe, i PrS) chelates to In III . Reaction of the indium(I) cluster In 4 [C(SiMe 3 ) 3 ] 4 with Ph 2 E 2 (E = S, Se and Te) and (tolyl) 2 Te 2 results in oxidative insertion of a (C(SiMe 3 ) 3 )In unit into the E-E bond generating ArEIn(C(SiMe 3 ) 3 )EAr.…”

Boron, aluminium, gallium, indium and thallium

“…100 The structure of 1,4-B 4 S 2 (NMe 2 ) 4 has been determined by gas-phase electron diffraction and quantum chemical calculations. 101 The silylaminofluoroboranes (Me 3 Si) 2 N-B(F)-N(R)SiMe 3 when reacted with a range of Lewis acids (AlClMe 2 , AlBr 3 and GaCl 3 ) have been shown to afford corresponding silylaminoborenes [Me 3 SiNQB-N(SiMe 3 ) 2 ] as adducts, e.g. [Me 3 Si(Cl 3 Ga)NBN(SiMe 3 )], the molecular structures of which has been determined by single crystal X-ray diffraction studies.…”