Endo- and Exocyclic Coordination of a 20-Membered N₂O₂S₂-Macrocycle and Cascade Complexation of a 40-Membered N₄O₄S₄-Macrocycle

Abstract

A 20-membered NOS-macrocycle (L) and a 40-membered NOS-macrocycle (L) 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 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 {[(μ-CuI)(HL)](CFCOO)} (1). Meanwhile, the reaction of L with Cu(ClO)·6HO afforded a typical endocyclic mononuclear complex [Cu(L)](ClO)·HO (2). In the reactions of L with CdX (X = Br and I), isostructural sandwich-type complexes [Cd(L)Br] (3) and [Cd(L)I] (4) were isolated. The treatment of L with Hg(ClO) also afforded a sandwich-type complex [Hg(L)](ClO) (5). One-pot reaction of L with a mixture of HgI and CdI afforded a dumbbell-type heteronuclear complex {[Cd(L)](μ-HgI)}[HgI] (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 (μ-HgI) cluster remaining another same cluster separately. The comparative NMR data exhibited a higher affinity of Cd(II) over Hg(II) toward L, in the parallel to the situation occurred in the solid state. Meanwhile, complexations of the extra-large macrocycle L is more challenging to afford some interesting dimercury(II) coordination products including a cascade complex. In solution, the dimercury(II) perchlorato complex of L 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(L)X] (7: X = I, 8: X = ClO) were prepared and characterized. Further, the dimercury(II) perchlorato complex 8 reacts with dabco to forms a cascade complex [Hg(L)(μ-dabco)(ClO)](ClO)·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.

From Short-Bite Ligand Assembled Ribbons to Nanosized Networks in Cu(I) Coordination Polymers Built Upon Bis(benzylthio)alkanes (BzS(CH2)nSBz; n = 1–9)

“…The cubane motif Cu 4 I 4 L 4 (L = thioether) is also well-known for its luminescence properties. − Indeed, many groups reported the emission spectra of Cu 4 I 4 L 4 -containing 0D, 1D, 2D, and 3D species. These species exhibit generally intense and structureless bands spreading from 430 to 730 nm at room temperature. ,,− ,,,,− The photophysical characterization of the thioether-containing cubanes and related species included in 0D–3D materials was extracted from more focused studies from the literature, and includes the emission lifetimes (τ e ) at 298 and 77 K, which generally range from 0.2 to 16 μs. A table containing these reported photophysical data is provided in Table S7. ,,,− ,,,,,,,, The cubane-containing CPs in this series make no exception (Figure ) with the small difference that some bands expand beyond 700 nm (near-IR).…”

Coordinative Networking of Thiacalix[4]-bis-monothiacrown-5 with Hard, Borderline, and Soft Metal Salts via Exo- and Endo/Exo-Coordination

“…As mentioned in Scheme , reactions of CuI with multidentate soft base ligands tend to lead the isolation of infinite coordination species because the CuI can adopt various structural motifs including rhomboid dimer, cubane tetramer, stepped cubane tetramer, 1D chain, and more due to their small energy difference. ,,,− In particular, the Cu n I n clusters can act as secondary building units (SBUs) in constructing low to high dimensional coordination polymers. The structural variations of the Cu n I n clusters are largely influenced by steric/electronic effects induced by the ligand conformation as well as synthetic conditions.…”

“…Structural modifications of calixarene moiety also enable to recognize some metal ions. − In such modifications, incorporation of crown loops onto the calix unit leads the family of calixcrowns. − In this case, controlling the size and/or donor atoms on the crown loop could provide new multitopic host to react a wide range of metal salts in constructing metallosupramolecules and coordination networks. Calix[4]-bis-crowns usually form dimetallic products with hard metal cations in an endocyclic (metal binds inside the cavity) mode, − while calix[4]-bis-thiacrowns often induce soft metal cations outside the cavity to yield exocoordinated complexes because of the electron-rich environment of the sulfur atoms. − Related to the exocoordination of thiamacrocycles, diverse types of coordinative networks showing coordination polymers, cyclic oligomers, and monomer complexes have been reported − and reviewed by us. − …”

Pillar[5]‐bis‐thiacrown: An Adaptive Tricyclic Host Selectively Recognizing an Organic Guest by Dimetalation

“…have reported dinuclear cryptand complexes in which an organic guest incorporates between two metal ions . We recently have reported the cascade complexation of a 40‐membered macrocycle that recognizes an organic guest via dimercury(II) complexation …”

“…[12] We recently have reported the cascade complexation of a4 0-membered macrocycle that recognizes an organic guest via dimercury(II) complexation. [13] Inspired by the dimetalationo fc alix[4]-bis-(thia)crowns [9] and the inclusion of dinitriles [3] into pillar [5]arenes,w ew ere interested in the modification of the pillar [5]arenes caffold to develop acandidate for dimetalation-mediated guest recognition. In the present study,w ew ished to explore on the pillar[5]-biscrown typeh ostb ecause of the followingr easons as depicted in Figure 1.…”