Synthesis of Novel Orthorhombic Mo and V Based Complex Oxides Coordinating Alkylammonium Cation in Its Heptagonal Channel and Their Application as a Catalyst

The effects of several alkylammonium cations on the synthesis of orthorhombic Mo 3 VO 11.2 complex oxides (MoVO) were investigated. First, we synthesized various alkylammonium isopolymolybdates as precursors for the synthesis of MoVO. Methylammonium heptamolybdate, dimethylammonium trimolybdate, ethylammonium trimolybdate, and ethylenediammonium trimolybdate were obtained as pure materials in new crystalline structures. Orthorhombic MoVO complex oxides were synthesized under hydrothermal conditions when (CH 3 NH 3 ) 6 Mo 7 O 24 and ((CH 3 ) 2 NH 2 ) 2 Mo 3 O 10 ·H 2 O were used. It was found for the first case that methylammonium cations and dimethylammonium cations were incorporated into the orthorhombic MoVO structure, forming compounds of Mo 32.3 V 7.7 O 112 (CH 3 NH 3 ) 4.0 ·9.7H 2 O and Mo 30.2 V 9.8 O 112 ((CH 3 ) 2 NH 2 ) 2.5 ·8.5H 2 O, respectively. These alkylammonium cations play an important role as a stabilizer in the synthesis of MoVO and act as a structure-directing agent for the orthorhombic phase.