Synthesis and Structural Characterization of Three Novel Macrocyclic Coordination Complexes Formed by Self‐assembly of Bridged Bi‐ or Tetrapyridine with Transition Metal Salts

Abstract

Self-assembly of a ferrocenyl-bridged bipyridine ligand bpef [bpef＝1,1'-bis(trans-2-pyrid-4'-ylethenyl)ferrocene] with silver triflate in CH 2 Cl 2 /MeOH or mercuric diiodide in MeCN/CH 2 Cl 2 gave the corresponding macrocyclic coordination complexes [bpef] 2 [AgSO 3 CF 3 ] 2 (1) and [bpef] 2 [Hg 3 I 6 ] (2) in 93% and 89% yields, respectively, whereas the pentaerythritolyl-bridged tetrapyridine ligand ptpc [ptpc＝pentaerythritol tetrakis-(4-pyridinecarboxylate)] reacted with cobalt thiocyanate via self-assembly to afford the macrocyclic coordination polymer [Co(NCS) 2 (ptpc)] n (3) in 90% yield. The X-ray diffraction analyses for 1-3 confirmed their novel macrocyclic structures and revealed that (i) the two silver atoms in complex 1 have an essentially linear geometry with N-Ag-N bond angle of 175.7° and 172.9°, (ii) the geometry of the middle mercury atom in complex 2 is square-planar, while the other two mercury atoms in the other two complexes are tetrahedral, and (iii) all the cobalt atoms in complex 3 adopt an octahedral geometry. In addition, the synthetic procedure for the known tetrapyridine ligand ptpc has been improved.