• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Infrared spectroscopy of divalent zinc and cadmium crown ether systems
【24h】

Infrared spectroscopy of divalent zinc and cadmium crown ether systems

机译：二价锌和镉冠醚系统的红外光谱

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The gas-phase structures of transition-metal dication (Zn~(2+) and Cd~(2+)) complexes with varying sized crown ethers, 12-crown-4 (12c4), 15-crown-5 (15c5), and 18-crown-6 (18c6), are investigated using infrared multiple photon dissociation (IRMPD) spectroscopy and quantum mechanical calculations. The measured spectra span the 750-1600 cm~(-1) infrared range, utilizing light generated by a free electron laser, and are compared to predicted spectra calculated at the B3LYP/6-311+G(d,p) or B3LYP/Def2TZVP levels of theory. Spectra with the largest and most flexible crown ether, 18c6, indicate that the crown is highly distorted, wrapping in a tight cage-like structure around both dications studied. The 15c5 adopts a folded orientation for the Zn~(2+) complex yet is almost planar when complexed with the larger Cd~(2+) ion. The Zn~(2+)(12c4) spectrum has bands appearing at lower frequencies than the other systems, consistent with an open conformation such that the metal is exposed, lying above the center of mass of the crown ether ring. The open structures of the Zn~(2+)(12c4) and Cd~(2+)(15c5) complexes have implications for solvent interactions in the condensed phase. The conformation of each metal-crown complex is highly dependent on metal size, charge, and crown ether flexibility, such that a delicate balance of minimizing the metal-oxygen bond lengths but maximizing the oxygen-oxygen distances arises. These competing influences are reflected in both the spectra and lowest-energy conformations.
机译：过渡金属指示剂（Zn〜（2+）和Cd〜（2+））配合物的气相结构，所述配合物具有不同的冠醚，12冠4（12c4），15冠5（15c5），和18-crown-6（18c6），使用红外多光子离解（IRMPD）光谱和量子力学计算进行了研究。利用自由电子激光产生的光，测得的光谱跨度在750-1600 cm〜（-1）红外范围内，并与在B3LYP / 6-311 + G（d，p）或B3LYP / Def2TZVP的理论水平。带有最大和最灵活的冠醚18c6的光谱表明，冠高度扭曲，包裹在研究的两种药物周围，呈密闭的笼状结构。 15c5对Zn〜（2+）络合物采用折叠方向，但与较大的Cd〜（2+）离子络合时几乎为平面。 Zn〜（2 +）（12c4）光谱的频带出现在比其他系统更低的频率上，这与开放构象一致，使得金属暴露在冠醚环质心上方。 Zn〜（2 +）（12c4）和Cd〜（2 +）（15c5）配合物的开放结构对缩合相中的溶剂相互作用有影响。每个金属-冠状配合物的构型高度依赖于金属的尺寸，电荷和冠醚的柔韧性，从而产生了最小化金属-氧键长度但最大化氧-氧距离的微妙平衡。这些竞争影响反映在光谱和最低能量构象中。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号