Phase Control of Ferromagnetic Copper(II) Carbonate Coordination Polymers through Reagent Concentration

Abstract

A significant degree of control over the dimensionality and magnetic connectivity of Cu II carbonate coordination polymers is achieved through varying the concentration of ammonia in the reactant solution. Higher concentration leads to a two-dimensional ferromagnetic [Cu 3 (2,4′-bipy) 6 (CO 3 ) 2 ] n 2n+ kagome structure while lower concentration develops a ferromagnetic [Cu(2,4′-bipy) 2 (H 2 O) 2 ][Cu(2,4′-bipy) 2 (CO 3 ) 2 ] chain (where 2,4′-bipy = 2,4′-bipyridine). The carbonate anion in the structures arises from the fixation of atmospheric CO 2 by the basic ammonia solution. Modelling the magnetic susceptibility of 1 [a]

Copper(II)-Assisted Ligand Fragmentation Leading to Three Families of Metallamacrocycle

“…Analyses of the hightemperature data (>150 K) using the Curie−Weiss law gave reasonable Curie constants in (emu K per copper atom) of 0.430(2) for SD/Cu6b, 0.434(2) for SD/Cu8b, and 0.434 (1) for SD/Cu16a. 48 These values translate to an average g-value of 2.147, consistent with reported literature values for Cu(II). 49 The Weiss temperatures in Kelvin, −214(2) for SD/Cu6b, −13(1) for SD/Cu8b, and −154(1) for SD/ Cu16a, again show the similarity of magnitude for SD/Cu6b and SD/Cu16a compared to SD/Cu8b.…”

“…This stems from the similar core structures for SD/Cu6b and SD/Cu16a which are quite different to that of SD/Cu8b . Analyses of the high-temperature data (>150 K) using the Curie–Weiss law gave reasonable Curie constants in (emu K per copper atom) of 0.430(2) for SD/Cu6b , 0.434(2) for SD/Cu8b , and 0.434(1) for SD/Cu16a . These values translate to an average g -value of 2.147, consistent with reported literature values for Cu­(II) .…”

“…The comforting result is that the C 2 H 2 O 4 4– ligand, only reported twice before, , is a very good organic connector for making magnets by virtue of the high exchange coupling energies implying it is potentially able to elevate the critical ordering temperature when involved in transition metal networks. It may be compared to other simple organic or inorganic oxo-ligands such as formate, oxalate, carbonate, sulfate, selenite, and phosphate and some transition metal-oxo anions such as molybdate and perrhenate that are commonly used in the area of metal–organic magnets. With these encouraging characteristics, further work using this ligand is highly recommended.…”

All about that base: investigating the role of ligand basicity in pyridyl complexes derived from a copper-Schiff base coordination polymer

“…3 As pyridines are readily functionalised, a wide range of different members of this family exist. 4,5 The size of this family gives coordination chemists a large variety of ligands to explore when constructing pyridyl complexes for catalysis, [6][7][8] spin crossover, 9,10 molecular magnets, 11,12 coordination polymers, [13][14][15] metal-organic frameworks, 16,17 medical imaging and therapeutic agents. 18,19 In our previous work, 20 we investigated the role of solubility of polypyridyl ligands (P) in the construction of coordination polymers and complexes synthesised from a copper Schiff-base starting material, {[Cu(L)]2}n, (compound 1, where L = 2-[(2hydroxybenzylidene)amino]phenol.…”

“…4-nbpy forms a complex similar to 2 (11, figure 2f). A literature report of [Cu(L)(imidazole)] 26 encouraged us to investigate the use of benzimidazole, which was successful and gave [Cu(L)(bnz)] (12), resulting in a structure similar to the [Cu(L)(M)] complexes (figure 1g).A complex was formed with isonicotinamide, but this required a modification to the procedure in that 30 % water was added to the reaction mixture to give [Cu(L)(H2O)(4-inam)].DMSO(13). In this complex, the plane of the isonicotinamde is substantially deviated from planar (figure 4) with the [Cu(L)] unit (66.3(6)°),…”