meso-四(对烷氧苯基)卟啉金属配合物的合成和性能研究(II)

合成了Zn、Pb两个系列卟啉金属配合物12个,其中6个为未见文献报道的新化合物,用元素分析、IR、UV、^1HNMR、MS确证了其结构。总结了Zn、Pb与卟啉类配体配合的IR、UV、^1HNMR判据。研究了这两个系列化合物的液晶性能,发现9个化合物具有液晶性。

Synthesis and properties of metallic complexes of Meso-tetrakis(4- alkoxyphenyl)porphyrins(II)

Meso - tetrakis (4 - alkoxyphenyl) porphyrins synthesized by condensation of 4 - alkoxybenzaldehydes with pyrrole, reacted with metal acetates to form corresponding complexes. Twelve complexes of porphyrins with Zn2 or Pb2 have been obtained by this approach. Among them there are six new compounds. Zinc series complexes are purple crystals, formed in 80% - 90% yieid. Lead complexes are green crystals with yields ranging from 52% to 58% . The solubility differences of target porphyrins and impurities in petroleum ether (naphtha) were exploited to improve the separation process and enhance recovery efficiency. Satisfactory purity of the porphyrins as achieved by one recrystal-ization. Compared with those of previous method, porphyrin complexes of approximately equal yields were obtained within shorter time and without need for inert atmosphere protection. Molecular structures of all synthesized compounds were confirmed by IR, UV, :H NMR, MS and elemental analysis . Characteristic spectrometric data of IR, UV, 1H NMR related to their structures have been systematically analyzed. The N - H 3385 cm-1 IR peak of porphyrins disappears when porphyrins combine with Zn2 or Pb2 ion. Compared with those in UV spectrum of porphyrin, the peaks of the complex shift to lower wave numbers.1 H NMR spectrums of porphyrins complexes do not show the peak at = - 2.75 as the porphyrin precursors. Differential scanning calorimetry (DSC) and polarizing microscope were used to probe the liquid crystal properties of the two series complexes. Nine of the two series complexes were found to exhibit liquid crystal properties. Only one synthesized substituted porphyrin which has as alkoxy chain with 16 carbon atoms shows liquid crystal properties. However, Zn2 , Pb2 complexes of substituted porphyrins which have alkoxy chain with 10, 12, 14, 16 or 18 carbon atoms possess liquid crystal properties and wide temperature range of liquid crystal phase transition.