Syntheses, crystal structures and electrochemical properties of three organic-inorganic hybrid supramolecular compounds based on copper-complex fragments and different polyoxometalates

Abstract

Three new organic-inorganic hybrid compounds H[Cu I (dafo) 2 ] 3 {[Cu I (dafo) 2 ] 2 P 2 W 18 O 62 } Á H 2 O (1), [Cu I (dafo) 2 ] 3 PMo 12 O 40 (2) and [Cu I (dafo) 2 ] 4 SiW 12 O 40 (3) (dafo = 4, 5-diazafluoren-9-one) have been hydrothermally synthesized and characterized by IR, TG and CV. Compound 1 exhibits a 3D supramolecular framework based on weak interactions between bisupported Dawson structure P 2 W 18 O 62 6-units and copper-complex fragments. With the aid of p-p stacking and hydrogen bonding interactions, a 1D supramolecular framework accommodating polyoxometalate (POM) anions is generated in 2. Compound 3 has similar fundamental units as 2, but the units are assembled in a different way. The distinction of their structures indicates that the POMs are the key factor in determining the frameworks of the final products. The electrochemical properties of these compounds have been studied using bulk-modified carbon paste electrodes.

Coordination chemistry and applications of versatile 4,5-diazafluorene derivatives

“…Dafo has been used as a ligand for metals across the periodic table: Mn, 43 Co, 44,45 Ni, [46][47][48] Cu, 44,[48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] Zn, 7 Mo, 63 Ru, 9,[64][65][66][67][68][69][70][71][72][73] Pd, 17,44,[74][75][76][77][78][79][80][81][82][83][84][85][86][87] Ag, [88]…”

“…104 There are several examples in the literature regarding inorganic-organic hybrid polyoxometallates which contain the Keggin-type cluster anions and metal-dafo complex cations (typically Cu, and in a few examples Ag or Cd). 50,51,57,59,60,90,97,105 The metal-dafo cation within these hybrid compounds seems to direct the assembly of other supramolecular interactions within the solid state. The coordination geometry of the metal, how the Keggin cluster is coordinated to the cation, and even the number of metals can play a role.…”