Anti and gauche conformers of an inorganic butane analogue, NH3BH2NH2BH3Electronic supplementary information (ESI) available: Crystallographic data, bond distances and angles, dihydrogen bond distance, and XRD pattern. CCDC 882868-882869. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2cc33621a

The crystal structures of an inorganic butane analogue, NH 3 BH 2 NH 2 BH 3 (DDAB), were determined using single crystal X-ray diffraction, revealing both anti and gauche conformations. The anti conformation is stabilized by intermolecular dihydrogen bonds in the crystal whereas two gauche conformations of DDAB observed in its 18-crown-6 adducts are stabilized by an intramolecular dihydrogen bond. The two gauche conformations show rotational isomerization but whether they are a pair of enantiomers is yet to be defined. Structural analysis demonstrates intermolecular dihydrogen bonds stabilize anti form and an intramolecular dihydrogen bond stabilizes the gauche conformer of NH 3 BH 2 BH 2 NH 3 .