Synthesis And Characterization Of New Open-framework Gallicm/Indium Phosphites

Inorganic materials are of considerable interest due to their rich structural chemistry and wide applications in the areas of catalysis, adsorption, and separations. The possibilities of replacing the tetrahedral phosphate group by a pseudo- pyramidal [HPO3]2- unit was first demonstrated by Clearfield and co-workers several years ago. Compared to phosphate, the phosphite group can only make three P-O-M bonds, which might be expected to lead to a new class of compounds with interesting architectures. With the several years development, a lot of metal phosphites with novel topologies and lower framework densities have been prepared. The metal has related to most main group metal and transition metal, part of lanthanide and actinouranium elements.Compared to transition metal phosphites, the reports of main group metal phosphites are rare. Up to now, only about twenty main group metal phosphites have been reported, but they possess interesting architectures. All of them are prepared under mild hydrothermal/solvothermal conditions in the presence of organic amines.With the aim of searching novel organically templated metal phosphites, we conducted our study on the hydrothermal/solvothermal synthesis in gallium/indium-phosphite-amine systems. Finally, seven gallium phosphites, three indium phosphites and two gallium phosphite-oxalate compounds have been prepared.In Ga2O3—H3PO3—amine systems, we synthesize seven gallium phosphites(1-7) by changing the amines and solvents. In the presence of 2,2'-bipyridine acting as a ligand, a new layed fluorinated gallium phosphite, Ga3F2(2,2'-bipy)2 (HPO3)2 (H1.5PO3)2 (1) with 10-membered ring windows viewed along the a-axis, has been hydrothermally synthesized. The adjacent layers are stably packed together and exhibit interesting three dimensional (3D) supramolecular array viaπ-πinteractions of the 2,2'-bipy groups. Additionally, compound 1 shows strong fluorescent property in solid state at room temperature. In the presence of 1,2-diaminocyclohexane (DACH) as a structure-directing agent, a new 2D layered gallium phosphite Ga(HPO3)F3·(trans-C6N2H16) (2), possessing left- and right- handed helical chains, has been solvothermally synthesized. The chirality of the racemic trans isomers of DACH can be transferred into the inorganic framework by hydrogen-bond. This reflects a chiral recognition phenomenon between the chiral organic templates and the chiral helical chains.Using diethylenetriamine (DETA) as template, a new open-framework gallium phosphite Ga5(OH)2(HPO3)8(C4N3H16)5H2O (3) is synthesized solvothermally. It is noted that compound 3 is the first gallium phosphite containing 5-coordinate gallium atom. In the presence of N, N-dimethyl piperazine and 2-methylpiperazine as template, respectively, two new 3D open-framework gallium phosphites Ga(HPO3) F2-(C6N2H16)0.5 (4) and Ga(HP03)F2(C5N2H14)o.5 (5) possessing left-and right-handed helical chains have been solvothermally synthesized, which show a low framework density value of 9.66. Use 1,4-butanediamine as template, two novel gallium phosphites Ga2F(HP03)3·(C4N2H14)0.5(6) and (7) have been prepared in solvothermal conditions. Compound 6 is the first gallium phosphite containing 4- coordinate gallium atom. Compound 7 contains 10-MR channels.In In2O3—H3PO3—amine systems, using different amines, we synthesize three indium phosphites (8-10) under hydrothermal conditions. Using achiral diethylenetriamine (DETA) as template, a new chiral open-framework indium phosphite In3(HPO3)6(H3DETA)-2H2O (8) has been synthesized under hydrothermal conditions. Interestingly, the host helical chain are presented in the 3D open-framework while fascinating hydrogen-bonded helices are self-assembled under hydrothermal conditions between organic template molecules and H2O molecules. It is worth noting that the guest hydrogen-bonded helical chain and the host helical ribbon of inorganic framework show the same chirality and intertwine with each other along the b axis. using 1,2-diaminocyclohexane (1,2-DACH) and 1,3-diaminopropane (1,3-DAP) as structure directing agents, respectively, two new three-dimensional indium phosphite and indium phosphite-phosphate [In3(H2PO3)3(HPO3)4]·(trans-C6N2H16) (9) and [In6(HPO3)8(H2PO3)5 (H2PO4)]'(C3N2H12)2 (10) have been synthesized under hydrothermal conditions. These two compounds have the similar 3D inorganic framework structures with the intersecting 8-membered ring (8-MR) channels. Compound 9 has the potential molecule recognition ability for the trans-isomers of the 1,2-DACH molecules. Moreover, it is noted that the chirality of trans-1,2-DACH alternates along the channels. Compound 10 is the first indium phosphite-phosphate compound.In Ga2O3—H3PO3—H2C2O4 systems, using imidazole as ligang or template, we synthesize two gallium phosphite-oxalate by the different solvents. Using the mixture of DMF and DOA as solvent, we get a 1D chain compound Ga(HPO3)(C2O4) (C3N2H4)(C3N2H5) (11). The oxalate group and imidazole molecule cap the ladder chain. Through the H-bond between N from imidazole molecule and O from oxalate group, the structure of compound 11 exhabits the interesting three dimensional (3D) supramolecular framework. Using the mixture of H2O and EG as solvent, we get a 3D open-framework structure constructed by 1D ladder chain and oxalate groups.In this paper, we describe the synthesis, crystal structures and characterizations of the twelve compounds. We hope the resultes can help to synthesize more metal phosphites with novel structure. The discussion of H-bonds interaction between organic amines and inorganic framework may conduce to the formation of specifical framework.