A two-dimensional layered manganese(II) pyrophosphate, 2[Mn3(P2O7)2(H2O)2] (1), has been synthesized hydrothermally. Its structure is determined by single-crystal X-ray diffraction analysis. Its structure is built up by MnO6 octahedra and P2O7 units, with ammonium NH4+ cations residing in the interlayer regions. The manganese pyrophosphate layer consists of infinite chains of cis and trans edge sharing MnO6 octahedra linked by P2O7 units. Magnetic susceptibility measurements show that this compound exhibits ferrimagnetic-like ordering below 3.2 K. Further study shows that there are two possible superexchange pathways via the oxygen anions in Mn2+ ions. Owing to the different bridging modes of O2-, the competition between ferromagnetic interactions and antiferromagnetic interactions in Mn2+ ions results in the ferrimagnetic behavior of 1.
A new metal-organic polymer Mn3（BTC）2(H2O)9·(H2O) was synthesized by reaction of the metal ions Mn（Ⅱ） with 1,3,5-benzenetricarboxylic acid(H3BTC) in a mixed solution of DMF/C2H5OH/(H2O) and crystallized.The crystal belongs to monoclinic system,space group C2/c with a=1.901 4（4） nm,b=0.740 23（15） nm,c=2.044 9（4） nm,β=97.18（3）°,V=2.855 5（10） nm3,Z=4,Dc=1.766（g/cm3）,μ（Mo Kα）=1.401 mm-1,R[I>2σ（I）]=0.072 7,wR=0.235 1 for 2 419 independent reflections with goodness-of-fit 1.046. Its structure possesses bilayer architectures constructed from Mn ions linked infinite Mn（BTC） chains which were build up from BTC ligand as the "T-shape" module and Mn as the linear module.The hydrogen-bond and π-π stacking interactions between bilayers make them three-dimensional channel-like interpenetrated frameworks.
Silica mesoporous materials were synthesized and used as the supporting materials for immobilization of enzyme.Penicillin G acylase,an enzyme which was used to produce 6-APA in pharmaceutical industry,was immobilized in the mesoporous materials by the immersion method.The stabilities of the immobilized penicillin G acylase were studied.After incubation at 60 ℃ for 2 h,the activity of immobilized penicillin G acylase remained 80% in the best case.At higher or lower pH,the free enzyme was deactivated quickly,while the immobilized enzyme still retained active.The result of operational stability showed that the immobilized(enzyme) retained 70% of its initial activity after operating for 6 times.These results showed that the stabilities of immobilized penicillin G acylase,related to the pore size of mesoporous materials,were increased significantly compared with those of free enzyme.The improvement of stabilities of immobilized enzyme was significant when the pore size of the mesoporous materials matched the enzyme molecule size.
The title compound Mn 3(BTC) 2(DMF) 4 (BTC=1,3,5-benzenetricarboxylic acid,DMF=dimethyl formamide) was synthesized under the mild conditions and its crystal structure was determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic system and belongs to space group P2 1/c with a =1.787 6(4) nm, b =1.179 7(2) nm, c =1.884 8(4) nm, β =116.35(3)°, V = 3.561 9(12) nm 3, Z =4, D c=7.413 Mg/m 3, M r=871.43, μ =5.081 mm -1 , F (000)=8 082, R = 0.045 6 , wR =0.106 3. Its structure reveals that each asymmetric unit of the title polymer contains three Mn(Ⅱ) ions,six BTC and four DMF ligands. The coordination of BTC ligands with Mn(Ⅱ) ions forms a 3D infinite framework having helical chains composed with 2 1 axes and about 0.6 nm× 0.8 nm channels along the [100] direction.
