Mn5(PO3(OH))2(PO4)2(H2O)4的水热合成和光谱研究

在水热反应条件下合成出具有红磷锰矿结构的Mn5(PO3(OH) ) 2 (PO4 ) 2 (H2 O) 4单晶 ,在X ray单晶结构分析的基础上 ,对其固体紫外可见漫反射光谱、红外光谱、荧光光谱和热重光谱进行了研究。结果表明 ,构成该化合物的PO4 四面体及MnO6 八面体通过共顶点或共棱方式相连接 ,与P ,Mn配位的氧分为 3类 :即端基氧 (Od)、二桥氧 (Ob)和三桥氧 (Oc)。因而在 2 10和 2 5 0nm左右出现了Od→Mn和Ob ,c→Mn的荷移跃迁吸收谱带 ;在 10 0 0～ 110 0cm- 1 处 ,P—O的伸缩振动峰分裂为 3个 ;70 0～ 980cm- 1 处存在 3类Mn—O的伸缩振动。对标题化合物分别采用 2 18和 310nm的光激发 ,分别在 35 4和 4 13nm产生强而尖锐的荧光光谱发射峰 ,表现了很强的光学效应。热重分析表明该化合物在 2 70℃以下结构保持稳定 ,在 2 70～36 0℃范围内失去配位水。量化计算得单点能为 - 4 5 5 8 6 5 95 5 5 1a u ;前线轨道能量HOMO(Alpha) =- 0 2 80 80a u ,LOMO(Alpha) =0 0 15 2 7a u ,能隙为 0 2 96 0 7a u ;HOMO(Beta) =- 0 2 5 919a u ,LOMO(Beta)=0 0 0 10 8a u ,能隙为 0 2 6 0 72a u ;偶极矩为 4 2 0 82Debye。

Hydrothermal Synthesis and Spectra Properties of Compound Mn5 (PO3 (OH))2 (PO4)2 (H2O)4

The title compound Mn5(PO3(OH))2(PO4)2(H2O)4 was synthesized under hydrothermal condition. Its crystal structure was determined by single-crystal X-ray diffraction. DRS, IR, fluorescence and TGA spectra were used to characterize the title compound. As a result, the compound is formed by linking with PO4 and MnO6, and the oxygen in it can be divided to three categories, so in IR spectra the characteristic peaks of Mn-O and P-O are separated in to three, respectively. In DRS there aretwo peaks at 210 and 250 nm coresponding Od-->Mn and Ob,c-->Mn. In fluorescence spectra the emission peaks are located at 354 and 413 nm when excited at 218 and 310 nm. Besides, thermal behavior of the compound is discussed by TGA diagrams. Finally, quantum chemistry calculation is performed to explain the structure characteristic. HF = -4558.6595551 a.u., HOMO(Alpha) = - 0.280 80a. u, LOMO(Alpha) = 0.01527 a.u., deltaE(Alpha) = 0.29607 a.u.; HOMO(Beta) = -0.25919 a.u., LOMO(Beta) = 0.00108 a.u., deltaE(Beta) = 0.260 72 a.u. and Dipole = 4.2082 Debye.