Novel Single‐Crystal‐to‐Single‐Crystal Anion Exchange and Self‐Assembly of Luminescent d¹⁰ Metal (Cd^II, Zn^II, and Cu^I) Complexes Containing C₃‐Symmetrical Ligands

Abstract

Ligands L1 and L2' (L1=N,N',N''-tris(4-pyridyl)trimesic amide, L2'=N,N',N''-tris(3-pyridinyl)-1,3,5-benzenetricarboxamide) belonging to an interesting family of tripyridyltriamides with C(3)-symmetry have been utilized to construct 3D porous or hydrogen-bonded frameworks. Through a novel single-crystal-to-single-crystal anion-exchange process, [Cd(L1)(2)(ClO(4))(2)](n) (1c) can be obtained from [Cd(L1)(2)Cl(2)](n) (1b) in the presence of ClO(4)(-) anions. This anion-exchange process is highly selective and only the substitution of Cl(-) by ClO(4)(-) or PF(6)(-) could be realized; Cl(-) was found not to be substituted by BPh(4)(-). This demonstrates that the exchange process depends on the size of the anions in relation to the size of the cavities in the host material (ca. 7.5 A). In addition, the anion-exchange properties of 1 b have also been investigated by means of powder X-ray diffraction (PXRD), elemental analysis (EA), and infrared absorption spectroscopy (IR). Structurally, [Zn(L1)(NO(3))(2)](n)(2) consists of a 2D coordination network with five-coordinate Zn(II) ions. Surprisingly, different trigonal-bipyramidal Zn(II) ions propagate to form distinct respective sheet structures, A and B, which are packed in an A-B-A-B manner in the crystal lattice, and these are hydrogen-bonded to give a 3D extended framework. The molecular structure of [CuI(L2')](n)(3) shows that the Cu(I) ion adopts a distorted tetrahedral geometry, and 3 also forms a 2D coordination network. Significantly, this 2D coordination network is further assembled into a remarkable 3D homochiral framework through triple hydrogen bonding and pi...pi interactions. All of these 3D coordination polymers and/or hydrogen-bonded frameworks are luminescent in the solid state, and their solid-state luminescent properties have been investigated at room temperature and/or at 77 K.

Dynamic Equilibria in Solvent‐Mediated Anion, Cation and Ligand Exchange in Transition‐Metal Coordination Polymers: Solid‐State Transfer or Recrystallisation?

“…[2, 41,51,52] For example, smaller ions would enter the crystalline lattice of a coordination polymer more readily than larger ions. However, the above experiment demonstrates that [Ag(4,4'-bipy)ClO 4 ] 1 is selectively formed in preference to the analogous NO 3 À or BF 4 À salts and as it is the least soluble of all the complexes in water, the whole process is governed by the solubility difference between complex products.…”

Diversified architectures of one-dimensional zinc(II) and cadmium(II) coordination polymers incorporating bipyridyl ligands: Syntheses, structures, theoretical studies, fluorescent and nonlinear optical properties

“…12) when excited at 367 nm and 384 nm, respectively. The emission of CP 3 could be assigned to the intraligand p-p ⁄ fluorescence emission, since the corresponding ligand 3,3 0 -pytz shows a similar emission at around 437 nm [59,60]. The emission spectrum of CP 4 (k ex = 355 nm) shown in Fig.…”

Sonochemical synthesis of a nano-structured zinc(II) amidic pillar metal–organic framework

“…These multifunctional moieties of amide groups tend to form hydrogen bonds among themselves and interact negligibly with guest molecules after construction of MOFs [13]. These structural frameworks have been utilized in applications such as chemical sieving, sensing, and catalysis, and much progress has been made in all of these areas [14]. By decreasing the size of metal-organic frameworks in nano-size, surface area would be increased.…”