Portal de Periódicos da CAPES

Struktur und X-X-Elektronendichteverteilung in Diaminoboranen des Typs (RCH 3 N) 2 BCH 3 mit R = H, CH 3

1991; De Gruyter; Volume: 46; Issue: 1 Linguagem: Inglês

10.1515/znb-1991-0117

1865-7117

Norbert Niederprüm, Roland Boese, Günter Schmid,

Hydrogen Storage and Materials

Using a miniature zone melting device with focused infrared light it was possible to grow crystals of bis(dimethylamino)methylborane (1) and bis(monomethylamino)methylborane (2) at temperatures o f 182 K and 177 K, respectively. The crystal structure and the X - X difference electron density have been determined at temperatures o f 120 K (1) and 115 K (2). 1 crystallizes in the orthorhombic space group Pbca with a = 758.87(7), b = 1559.74(12) and c = 1296.73(12) pm. The mean B - N distance is 143.1(3) pm. 2 crystallizes in the monoclinic space group P2 1 /c with a = 775.06(6), b = 1533.94(17), c = 1011.06(10) pm and β = 102.669(7)° with intermolecular N ··· H hydrogen bridges. The mean B - N distance is 141.5(2) pm. It is shown that the variation of torsion angles at small angles has more influence on bond lengths than the same or a greater variation at large angles and that it is necessary to pay more attention to the torsion angles ( C - B - N - C ) rather than to the interplanar angles (plane N ,B,N - plane N ,C,C ).