화학공학소재연구정보센터
Inorganic Chemistry, Vol.57, No.11, 6289-6299, 2018
Endo- and Exocyclic Coordination of a 20-Membered N2O2S2-Macrocycle and Cascade Complexation of a 40-Membered N4O4S4-Macrocycle
A 20-membered N2O2S2-macrocycle (L-1) and a 40-membered N4O4S4-macrocycle (L-2) were employed as a [1:1] and a [2:2] cyclization product, respectively, for the preparation of diverse types of supramolecular complexes including a cascade complex. Six complexes (1-6) of the smaller macrocycle L-1 including discrete to continuous forms, mono- to heteronuclear, and endo-to exo-and endo/ exocoordination were prepared and their coordination modes were discussed systemically. First, the reaction of L' with CuI in the presence of trifluoroacetic acid afforded an exocyclic 1-D coordination polymer 1[(mu(4)-Cu4I4)(HL1)(2)](cF(3)COO)(2)}(n), (1). Meanwhile, the reaction of L1 with Cu(ClO4)(2).6H(2)O afforded a typical endocyclic mononuclear complex [Cull(L1)](C104)2,-1-120 (2). In the reactions of L' with CdX2 (X = Br and I), isostructural sandwich-type complexes [Cd(L')2Br2] (3) and [Cd(12)(2)I-2] (4) were isolated. The treatment of L' with Hg(C104)2 also afforded a sandwich-type complex [Hg(L-1)(2)](ClO4)(2) (5). One-pot reaction of L' with a mixture of Hg12 and CdI2 afforded a dumbbell-type heteronuclear complex {[Cd(L-1)](2)(j4-Hg2I6)}[Hg2I6] (6), in which, the Cd(II) ion occupies the macrocyclic cavity. Further, such two endocyclic Cd(II) complex units are bridged by a square-type (y-Hg216)2-cluster remaining another same cluster separately. The comparative NMR data exhibited a higher affinity of Cd(II) over Hg(II) toward L1, in the parallel to the situation occurred in the solid state. Meanwhile, complexations of the extra-large macrocycle L2 is more challenging to afford some interesting dimercury(II) coordination products including a cascade complex. In solution, the dimercury(II) perchlorato complex of L2 as a metalloligand shows a preferential binding of dabco (1,4-diazabicyclo[2,2,2]octane), but its dimercury(II) iodo complex has a much smaller affinity for dabco. In order to explain these results, the solid dimercury(II) complexes with different anions [Hg-2(L-2)X-4] (7: X = I, 8: X = ClO4) were prepared and characterized. Further, the dimercury(II) perchlorato complex 8 reacts with dabco to forms a cascade complex [Hg-2(L-2)(mu-dabco)(ClO4)(2)](ClO4)(2).2DMF.2ether (9), exhibiting its formation being metal-driven and coordinated anion-regulated. The observed cascade complexation both in solution and solid states is an example of the adaptive guest binding.