Correlating Structural Features and 207Pb NMR Parameters with the Stereochemical Activity of PbII Lone Pairs in Birefringent Pb[2,6-bis(benzimidazol-2-yl)pyridine] Complexes
详细信息 查看全文
- 作者：John R. Thompson ; David Snider ; John E. C. Wren ; Scott Kroeker ; Vance E. Williams and Daniel B. Leznoff
- 刊名：European Journal of Inorganic Chemistry
- 出版年：2017
- 出版时间：January 3, 2017
- 年：2017
- 卷：2017
- 期：1
- 页码：88-98
- 全文大小：2394K
- ISSN：1099-0682c
文摘
A series of PbII materials containing the highly anisotropic tridentate ligand 2,6-bis(benzimidazol-2-yl)pyridine (bbp) and [Au(CN)2]–, Hg(CN)2 or halide bridging units, [Pb(bbp)Br2]·2H2O, Pb(bbp)I2, [Pb(bbp)I]2(µ-I)[Au(CN)2], [Pb(bbp)Br]2(µ-Br)[Au(CN)2], [Pb(bbp)Br2][Hg(CN)2], Pb(bbp)Cl[Au(CN)2]·0.25H2O and Pb(H2O)(bbp)2[Au(CN)2]2, have been prepared, structurally characterised and investigated spectroscopically by 207Pb solid-state NMR spectroscopy. Of these, five possess similar coordination geometries, providing an ideal series to investigate structural parameters as indicators for stereochemical activity by correlation with the 207Pb chemical shift span parameter (Ω). The bond length of the substituent opposite to the stereochemically active lone pair and the angle between axial ligands were found to correlate weakly with Ω for these compounds (R2 = 0.85 and 0.66, respectively) and an expanded set of compounds with varying components and structures (R2 = 0.60 and 0.67, respectively), which indicates that these (or similar) structural parameters or Ω can be used to estimate the degree of lone-pair activity. Compounds were also found to be highly birefringent with values ranging from 0.31(5) for Pb(H2O)(bbp)2[Au(CN)2]2 to 0.660(4) for [Pb(bbp)Br2]·2H2O, the latter being amongst the most birefringent compounds reported.