Assembling [M(P 4 Mo 6 ) 2 ] (M = Na, Mn, Na/Cu) dimeric clusters via transition metal/sodium ions into 0D to 3D phosphomolybdates

Six phosphomolybdate compounds based on the sandwich-type cluster [M(P 4 Mo 6 X 31 ) 2 ] (M = Na, Mn, Na/Cu; X = O or OH) have been solvothermally synthesized by using various organic/inorganic cations as templates, namely, (H 3 AEP) 4 [Na(P 4 Mo 6 O 31 H 5.5 ) 2 ]·4H 2 O ( 1 ), (Me 2 NH 2 ) 7 [NaMn(H 2 O)][Mn(P 4 Mo 6 O 31 H 6 ) 2 ]·5H 2 O ( 2 ), (H 4 tpc) 0.5 (H 4 tpb) 0.5 (H 0.5 bpp)[Na 2.5 (H 2 O)][Na(P 4 Mo 6 O 31 H 8 ) 2 ]·2H 2 O ( 3 ), (Me 2 NH 2 ) 6.5 [Na 4 (H 2 O) 8 ][Cu 0.25 Na 0.75 (P 4 Mo 6 O 31 H 6.25 ) 2 ] ( 4 ), (Me 2 NH 2 ) 1.5 (NH 4 ) 4 [Mn 1.5 Na 4.5 (H 2 O) 7 ][Mn(P 4 Mo 6 O 31 H 4.5 ) 2 ]·3.5H 2 O ( 5 ), and (DMIm) 4 [Mn 1.5 Na 2 (H 2 O) 8 ][Mn(P 4 Mo 6 O 31 H 6.5 ) 2 ]·1.5H 2 O ( 6 ) (AEP = 1-(2-aminoethyl) piperazine, Me 2 NH = dimethylamine, bpp = 1,3-bis(4-pyridyl)propane, tpb = 1,2,4,5-tetra(4-pyridyl)-benzene, tpc = a , a -1,4-dihydroxy- e , e , e , e -1,2,4,5-tetra-(4-pyridyl)cyclohexane, and [DMIm] = 1,3-dimethylimidazolium). These compounds were characterized by elemental analysis, PXRD, IR, TGA, and single-crystal X-ray diffraction. Compound 1 features a classical zero-dimensional (0D) dimeric cluster [Na(P 4 Mo 6 O 31 H 5.5 ) 2 ]. Compound 2 possesses a 1-D chain constructed from the linkage of [Mn(P 4 Mo 6 O 31 H 6 ) 2 ] dimeric clusters and M (M = Na + , Mn 2+ ) linking metal ions. Compounds 3 and 4 are characteristic of 2-D layers, which are built up by connecting [Na(Mo 6 P 4 O 31 H 8 ) 2 ] and [M(Mo 6 P 4 O 31 H 6.5 ) 2 ] (M = Cu 0.25 /Na 0.75 ) dimeric clusters, respectively, via Na + ions. Compounds 5 and 6 feature 3D frameworks, where the dimeric clusters are interconnected by M (M = Na + , Mn 2+ ) ions. Thus, the application of linking metal ions with different coordination modes and valence states to assemble [M(P 4 Mo 6 X 31 ) 2 ] clusters is promising for harvesting new phosphomolybdates. In particular, compounds 1 and 5 exhibited visible light degradation performance for Rhodamine B.