CRCU

Chemical Research in Chinese Universities ›› 2013, Vol. 29 ›› Issue (4): 621-626.doi: 10.1007/s40242-013-2446-7

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One Dimensional Iron Molybdophosphate Anionic Chains with Different Structural Arrangements Reflecting a Flexibility Character

ZHOU Yun-shan, HASSAN ul Sadaf, LI Xian-qi, ZHANG Li-juan, AHMAD Waqar, SHI Zong-hai   

  1. State Key Laboratory of Chemical Resource Engineering, Institute of Science, Beijing University of Chemical Technology, Beijing 100029, P. R. China
  • Received:2012-11-19 Revised:2013-02-06 Online:2013-08-01 Published:2013-07-15
  • Contact: ZHOU Yun-shan, ZHANG Li-juan E-mail:zhouys@mail.buct.edu.cn;ljzhang@mail.buct.edu.cn
  • Supported by:

    Supported by the National Natural Science Foundation of China(Nos.20771012, 20541001).

Abstract:

Structural comparison of a new compound[(bpp)3H6]Fe2IIIFe2IIMo24V(H2PO4)8(HPO4)4(PO4)4O48(OH)12· (H2O)4·2H2O(1)[bpp=1,3-di(4-pyridyl)propane] with our previously reported two compounds[(bpy)3FeII]3· Fe2IIIFe2IIMo24V(H2PO4)8(HPO4)4(PO4)4O48(OH)12(H2O)4·12H2O(2) and[(bpy)3FeII]2FeIIFeIIIMo12V(H2PO4)2(H2-xPO4)·(H1+xPO4)(HPO4)2(PO4)2O24(OH)6(H2O)2·9H2O(x=0―1)(3)(bpy=2,2'-bipyridine), which all exhibit one-dimensional mixed-valence iron molybdophosphate anionic chains constructed by alternating connection of FeIII ions and magic[FeII(Mo6P4O31)2] units, reveals that the non-hydrogen atomic ratios of Mo:Fe:P:O within the polymeric anionic chains are the same for all the three compounds, while the polymeric anionic chains of the different compounds bear different numbers of negative charges. And therefore there exist different numbers of counter cations per {Fe2III[Fe2II(P16Mo24VO124)]} unit found in the titled compounds. It discloses that not only are the spatial assembling of counter cations and polymeric inorganic chains of three compounds quite different, but also the O―FeIII―O bond angles and FeIII―O bond lengths of the three different inorganic chains exhibit small differences. What is more important is that such small changes in bond length and bond angle in the assemblage of FeIII―O bonds lead to the considerable fluctuations of inorganic chains in their structural conformation within the three compounds, reflecting an interesting phenomenon of “flexibility" in the pure inorganic one dimensional mixed-valence iron molybdophosphate chains.

Key words: Flexibility, Conformation, Crystal structure, Inorganic chain, Iron molybdophosphate