ALKYLAMMONIUM HEXACHLOROMETALLATES .4. SYNTHESIS AND CRYSTAL-STRUCTURE OF BIS(1,4-DIAMMONIOBUTANE) DIAQUAHYDROGEN HEXACHLORORHODATE(III) DICHLORIDE, [H3H-(CH2)(4)-NH3](2)[H5O2][RHCL6]CL-2

Bis(1,4-diammoniobutane) diaquahydrogen hexachlororhodate(III) dichlor ide, [H3N-(CH2)(4)-NH3](2)[H5O2] [RhCl6]Cl-2 (1), was synthesized by t he reaction of rhodium(III) chloride with 1,4-diaminobutane dihydrochl oride in concentrated hydrochloric acid. The red compound slowly decom poses at room temperature, but is stable for months and up to 106 degr ees C (DTA) under hydrogen chloride. Crystals of 1 were obtained by di ffusion-controlled crystallization (space group <(P)over bar 1>). The solid-state structure can be considered as a sequence of layers Linked by hydrophobic interactions between the aliphatic chains of the 1,4-d iammoniobutane ions. Within these layers the hydrophilic building bloc ks (hexachlororhodate and chloride anions, the diaquahydrogen cations and the ammonio groups of the diammoniobutane cations) are connected b y a complex system of O-H ... Cl and N-H ... Cl hydrogen bonds. The H5 O2+ ion has a crystallographically imposed C-i symmetry and shows the typical 1:1 disorder of the central hydrogen atom for a symmetrically strong [O ... O 2.406(10) Angstrom] double-minimum potential O-H-O bon d.