Effects of Anion and Bipyridyl Bridging Ligand Identity on the Co(II) Coordination Networks

Abstract

Five new coordination polymers, {[Co-(OAc) 2 (bpe)(H 2 O)]•0.5(dmf)} n (1), {[Co(bpy) 2 (H 2 O) 4 ]-[Co(tfa)(bpy) 2 (H 2 O) 3 ](tfa) 3 •1.5(bpy)} n (2), [Co-(tfa) 2 (dps) 4 ] n (3), {[Co(tfa) 2 (bpe) 4 ]•H 2 O} n (4), and [Co-(tfa) 2 (bpp) 4 ] n (5) (where AcO − = CH 3 CO 2 − ; tfa − = CF 3 CO 2 − ; bpy = 4,4′-bipyridine; bpe = 1,2-bis(4-pyridyl)ethane; bpp = 1,3-bis(4-pyridyl)propane; dps = 4,4′-dipyridyl sulfide; dmf = N,N′-dimethylformamide) were synthesized by the reactions of Co(OAc) 2 •4H 2 O and Co(tfa) 2 •4H 2 O with different dipyridyl ligands and characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. Compound 1 exhibits extended two-dimensional (2D) networks through the bridging AcO − and bpe ligands. The polymeric motifs in 2−5 are exclusively based on bipyridine-type ligands and results in 1D cationic chains in 2, similar charge-neutral double tapes in 3 and 4, and a 2D polymeric network in 5. In 2−5, the tfa anions coordinate to the Co(II) center in a monodentate mode. An impact of the anion's fluorination on coordination modes and supramolecular architectures is registered. Magnetic measurements reveal almost vanishing exchange interactions in the layered materials 1 and 5. The correlation of mechanical properties and crystal structure has been demonstrated for 1.

Structural versatility driven by the flexible di(4-pyridyl) sulfide ligand: From cobalt(II) single-ion magnets to sheet-like copper(II) weak antiferromagnets

“…The negligible exchange magnetic coupling through the dps ligand was confirmed through magnetic measurements. Other examples also show that the extended double dps bridges are very poor mediators of magnetic interactions between the copper(II) ions [16,18]. The magnetic behavior observed in the [Cu 2 (O 2 CC 8 H 9 ) 4 (dps)] n system is due to the presence of interactions between copper(II) ions through carboxylate groups [1,19].…”

“…Several examples of systems obtained using dps ligand were summarized (compounds published from 2006 to 2018) in Table S1 in the Supporting Information (SI) highlighting the choice of this ligand for this work. These systems include discrete compounds [15,[20][21], one-dimensional (1-D) [1,[14][15][16][17]19,22], two-dimensional (2-D) [7,21,[23][24][25] and three-dimensional (3-D) [26][27][28] coordination polymers in addition to 3D metal-organic frameworks [24,[29][30] and sandwich-like structure [31].…”

New binuclear copper(ii) coordination polymer based on mixed pyrazolic and oxalate ligands: structural characterization and mechanical properties

“…Furthermore, the use of different ligands with similar coordination abilities but different exibilities as building blocks could be considered as a smart procedure for obtaining periodic frameworks. [7][8][9] In contrast to the large number of recent publications describing the synthesis and characterization of MOM structures, studies focusing on understanding the mechanical properties of these hybrid materials are still scarce due to the lack of proper measurement tools. 10 Nonetheless, recent advances in this eld are shedding some light on the fundamental structure-mechanical property relationships, which are needed for optimized design and successful performance in diverse technological applications.…”

Structure and mechanical features of one-dimensional coordination polymer catena-{(μ2-adipato-O,O′)-bis(pyridine-4-aldoxime)-copper(ii)}

“…A similar effect of the oscillation appearance has been observed in our previous studies under NI of the SiO 2 -P 2 O 5 - Nd 2 O 3 glassy film, coated systems of ITO/Si and SnO 2 /Si, and metal-organic materials. 16,[39][40][41][42] The serrating (oscillating) character of the plastic deformation at low peak load was also seen in studies on ionic, covalent, vitreous and other materials, [43][44][45] i.e. it may have a common origin.…”

“…15 Our own recent findings in this area revealed the anisotropy of hardness and plasticity of the layer surface for the laminar structure {[CoIJAc) 2 IJbpe)IJH 2 O)]Ĵ0.5IJdmf)} n , where Ac = acetate, bpe = 4,4′-bipyridine ethane, dmf = N,N′dimethylformamide. 16 For organic crystals on the other hand, the recent reports revealed the different mechanical properties for the polymorphs of sulfathiazole and curcumin, 17 the impact of weak interactions on mechanical properties of caffeine cocrystals, 18 and the deteriorated plasticity of piroxicam-saccharin cocrystals as a function of crystal packing. 19 The mechanically induced molecular migrations reported for the layered homomolecular (thiohydantoin) 20 and heteromolecular (TCNB:pyrene) solids were explained in terms of mobility of the weakly bound arrays, and the nanoindentation technique was suggested as an effective tool to study layered crystal packing.…”