Template synthesis and characterization of a novel three-dimensional open-framework indium phosphate (C6N4H22)1/2[In3(HPO4)6] · H3O

A novel indium phosphate has been prepared hydrothermally using trithylenetetramine as template. The compound (C6N4H22)1/2[In3(HPO4)6] · H3O crystallized in the monoclinic system, space group C2/c (No. 15) with cell parameters a = 18.313(4) Å, b = 8.8229(18) Å, c = 16.221(3) Å, β = 111.70(3)°, V = 2435.1(8) Å3 and Z = 2; the final residual factor were R = 0.0239 and Rw = 0.0662. The structure consists of two similar secondary building units (SBUs), [In3(PO3(OH))6], featured by two [3.3.3] propellane-like chiral motifs with Δ and Λ configuration, respectively. These SBUs construct to 3-D framework containing 1-D straight channels with eight-membered rings along [1 1 0] direction, the fully-protonated organic amine molecules and H3O+ are located in the channels and neutralize the negative charges of the inorganic framework. The further characterizations of the compound have been performed by X-ray powder diffraction, ICP, IR and TG-DTA analyses.