Selective binding of open frameworks assembled from nickel(II) macrocyclic complexes with organic and inorganic guests

Inclusion studies for metal-organic open-frameworks. [Ni(C10H24N4)(H2O)(2)](3)[BTC](2).24H(2)O (1) and [Ni(C10H26N6)](3) [BTC](2).18H(2)O (2) (BTC3- = 1,3,5-benzenetricarboxylate) with various organic and inorganic guest molecules have been carried out. 1 is the previously reported molecular floral lace with I-D channels, where positively charged macrocyclic layers and negatively charged BTC3- layers are alternately packed by hydrogen bonding interactions. 2 is assembled in this study from nickel(II) hexaazamacrocyclic complex containing methyl pendant arms and BTC3-. The X-ray structure of 2 shows that the nickel(II) complex and BTC3- form a 2-D coordination polymer. The XRPD patterns of 2 indicate that framework of 2 is slightly deformed upon removal of water guest molecules but restored upon rebinding of water. The host solid 1 binds MeOH in toluene, and 1,3,5-trihydroxybenzene (THB) and 4-hydroxyacetophenone (HAP) in EtOH/toluene (v/v = 1/4) solutions. The binding constants (K-f) of 1 for MeOH, THB, and HAP are 66.4 M-1. 259 M-1, and 13,9 M-1, respectively. In the range of high concentration of the guest, however, the host shows various binding curves depending upon the types of guest. It binds PhOH in toluene, showing a sigmoid curve. It also binds transition metal complexes such as [Cu(NH3)(4)](ClO4)(2), [Cu(ethylenediamine)(2)](ClO4)(2), [Cu(histamin)(2)](ClO4)(2), and [Cu(N,N'-bis(3-aminopropyl)ethylenediamine)](ClO4)(2) in MeCN. with K-f values of 645 M-1, 9.52 M-1, 37.2 M-1, and 6.00 M-1, respectively. The host solid 2 binds selectively PhOH over PhCl and PhBr, showing that hydrogen bonding interaction between the host and guest plays an important role in the selectivity.