From Metallacyclophanes to 1-D Coordination Polymers:  Role of Anions in Self-Assembly Processes of Copper(II) and 2,5-Bis(3-pyridyl)-1,3,4-oxadiazole

Abstract

The reaction of various CuII salts with 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L) in CH3CN-H2O medium affords different complexes, the solid structures of which are controlled only by the choice of the counteranions. Reaction of Cu-(ClO4)2.6H2O or Cu(NO3)2.3H2O and L yields the novel bimetallic macrocyclic complex [Cu2L2(H2O)6](ClO4)4(H2O)4 (1) [monoclinic, space group P21/m, a = 8.745(5) A, b = 16.179(10) A, c = 14.930(8) A, beta = 93.253(10) degrees, Z = 2] or [CuL(NO3)2]2(CH3CN)2 (2) [triclinic, space group P1, a = 7.863(3) A, b = 8.679(3) A, c = 13.375(5) A, alpha = 74.121(5) degrees, beta = 78.407(6) degrees, gamma = 86.307(6) degrees, Z = 1]. However, with the replacement of CuII perchlorate or nitrate salts with CuSO4.5H2O or Cu(OAc)2.H2O in the above reaction, two different one-dimensional (1-D) coordination polymers [[Cu2L2(H2O)6(SO4)2](H2O)6]n (3) [triclinic, space group P1, a = 7.078(3) A, b = 11.565(4) A, c = 12.561(5) A, alpha = 109.511(6) degrees, beta = 105.265(6) degrees, gamma = 94.042(6) degrees, Z = 1] or [[Cu2L(mu-OAc)4]]n (4) [monoclinic, space group C2/c, a = 20.007(7) A, b = 7.506(2) A, c = 16.062(5) A, beta = 108.912(5) degrees, Z = 4] were obtained. These results unequivocally indicate that the nature of the counteranions, which play different roles in each complex, is the key factor governing the structural topologies of them. The magnetic properties of these CuII complexes have been investigated by variable-temperature magnetic susceptibility and magnetization measurements, and the magneto-structural correlation has been analyzed in detail.

Self‐assembly process of copper cation and 2,5‐bis(3‐pyridyl)‐1,3,4‐oxadiazole under electrospray ionization conditions

“…7 The ESI mass spectrum shown in Fig. 1 17 We also found that formation of this complex in the gas phase does not take place when another copper salt ( Fig. 2(a)) or another solvent is used ( Fig.…”

“…[1][2][3][4][5][6][7][8] Because of the wide spectrum of biological activity of 1,3,4-oxadiazoles, their copper complexes have attracted much attention. [9][10][11][12][13][14][15][16][17] It has been shown that 2,5-bis(2-pyridyl)-1,3,4-oxadiazole forms 2:1 copper complexes 9,11 and that 2,5-bis(3- (Fig. 1).…”

“…For the condensed phase the above complex was formed for the solution containing 1 and Cu(ClO 4 ) 2 at equimolar concentration. 17 The ESI mass spectra were obtained on a Waters/Micromass (Manchester, UK) ZQ2000 mass spectrometer (single quadrupole type instrument, Z-spray, software MassLynx V3.5). The sample solutions were prepared in methanol or in acetonitrile/water (1/1 v/v).…”

Anion-Controlled Architecture and Photochromism of Naphthalene Diimide-Based Coordination Polymers

“…As we know, anions play important roles in the formation of coordination polymers. For example, some anions, such as X − , NO 3 − , and CH 3 COO − with strong coordination ability can coordinate to metal ions or bridge metal centers to generate multi-nuclear units or high-dimensional frameworks [15][16][17][18], but some other anions, such as PF 6 − , ClO 4 − , BF 4 − , and CF 3 SO 3 − possess very weak coordination ability and usually act as counterions and templates in the formation of the products [19][20][21]. Although many studies on anion-controlled formation of coordination polymers have been reported, very few examples of anion effect on the photochromic properties of coordination polymers have been involved so far because it is usually difficult to create appropriate coordination polymers with photochemical activity, but also containing different anions [22][23][24].…”

{[CuI(bpo)2(CH3CN)]ClO4·CH3CN·(H2O)1.5}n: a novel three-dimensional open framework with large rectangular channels assembled from copper(I) perchlorate and 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (bpo)

“…Aromatic-aromatic or p-p stacking interaction is one of the important types of non-covalent intermolecular forces similar to hydrogen bonding and has been recognized to play a key role in the stabilization and regulatory functions of both biological systems and supramolecular construction, where it contributes significantly to self-assembly and molecular recognition processes [11][12][13]. However, in contrast to the wellunderstood hydrogen bonding interaction, the nature and utilization of p-p interaction, mainly for further development of supramolecular chemistry and prediction of crystal structures, is still not well documented [14].Recently, we have initiated a research program for the construction of various supramolecular architectures with interesting extended frameworks based on a designed angular dipyridyl ligand, 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (bpo) and its 3-pyridyl isomer [15][16][17][18]. The role of subtle controlling factors, especially the use of counter anions, of the self-assembly processes in the formation of these novel coordination polymers or supermolecules was investigated in detail.…”