氯化二(羟胺根)·(羟胺—O)·水合氧钒(Ⅴ)[VO·(NH_2O)_2·(NH_3O)·H_2O]Cl的晶体结构

CRYSTAL STRUCTURE OF HYDRATED (BIS-HYDROXYLAMINO)(HYDROXYLAMINE) OXOVANADIUM(V)CHLORIDE [VO·(NH_2O)_2(NH_3O)·H_2O]Cl

调节硫酸氧钒与盐酸羟胺溶液至pH～4制得的题目晶体属空间群P2_1/n,晶胞参数a=8.201,b=8.597,c=9.947A,β=93.00°,Z=4.结构解出精修后R因子为0.069.结果表明,不对称单位中二个羟胺根以侧接态与VO^(3+)配位,另一羟胺取端接态以O占据V的第五赤道配位位置,配位水处于氧钒基强键反位,Cl^-则在配阳离子界外以平衡电荷,晶体对的化学式确证为[(VO^(3+))(NH_2O~_)_2(NH_3O)(H_2O)][Cl^-]

Using KOH to control pH- 4, the title complex has been prepared by reaction of VOSO4 with NH2OH · HC1 in aqueous solution. The complex crystallizes in space group C2h5-P 21/n with unit cell constants a = 8.201(5),A = 8.597(5),c = 9.947(6)A,β= 93.00(5)°,Z=4 and dm = 2.05,d, = 2.06 g·cm-3. The structure was solved by direct method and Fourier difference techniques using SHELXTL software. The least-squares refinement for 100 structure parameters gave a final discrepency factor R = 0.069. The structural analysis shows that the vanadyl ion VO2+ has already been oxidized and converted to VO3+ group which forms a seven-coordinated cation in crystal with four ligands of three hydroxyamino groups and one water. The coexistence phenomenon of both side-on and end-on binding mode between vanadium atom and hydroxyamino groups is very interesting. Carefully considering all the information of bond parameters, calculate results got from quantum chemical EH MO program as well as the theoretical analyses using Bond-Valence Theory, we have identified that the two side-on hydroxyamino groups as -ONH2 species while the end-on one as the -ONH3+ species.