Survival of the Fittest Nanojar: Stepwise Breakdown of Polydisperse Cu₂₇−Cu₃₁ Nanojar Mixtures into Monodisperse Cu₂₇(CO₃) and Cu₃₁(SO₄) Nanojars

Abstract

In one word,h ow would you describe your research? Spectacular!Did serendipity play apart in this work?Serendipity plays ac ontinuous role in our research, from the initial discovery of this novel class of extremely efficient anion incarcerating agents, which we termed nanojars, to the current results presented here.What was the biggest surprise (on the way to the results presented in this paper)?Given the structural complexity and novelty of nanojars, certainly nobody could have predicted the effect of ammonia on an anojar mixture. It was indeed ah uge surprise to find that one of the five homologous nanojars in the mixture is totally resistant to the action of NH 3 in solution, while the other four break down and rearrange into the NH 3 -resistant one.What was the biggest challenge( on the way to the results presented in this paper)?Although nanojars are readily synthesized, they always form as am ixture of nanojars of different sizes. Apart from crystallization that occasionally results in af ew small crystals, all common separation methods failed to provide larger samples of pure, individual nanojars. What aspects of this project do you find most exciting?This project involves ac omplex array of techniques, including covalent synthesis of new organic ligands, supramolecular/coordination self-assembly,X -ray crystallography,m ass spectrometry and nuclear magnetic resonance techniques, which all unveil unique, intriguing results about nanojars, and point to potential applications. The most exciting part of our research always is designing the next step, and awaiting for the results of the new experiments. Does the research open other avenues that you would like to investigate?One new avenue we are currently exploring is the selective extraction of anions from contaminated water,i ncluding highly toxic anions, such as arsenate, chromate and selenate, using nanojars.Invited for the cover of this issue is the team led by Gellert Mezeia tW estern Michigan University.T he image depicts "ammonia" selectively breakingd own nano jar mixtures into pure nanojar species, but one resists!R ead the full text of the arti-

Capped Nanojars: Synthesis, Solution and Solid-State Characterization, and Atmospheric CO2 Sequestration by Selective Binding of Carbonate

“…Standing for 12 days resulted in no visual changes. ESI-MS(−), however, shows the disappearance of the peaks at m / z 2171, 2245, and 2318 and displays only one major peak at m / z 2023 (Figure S6), indicating the conversion of Cu 3 -Cu 29 , Cu 3 -Cu 30 , and Cu 3 -Cu 31 to Cu 3 -Cu 27 , similarly to the conversion of Cu 29 , Cu 30 , and Cu 31 to Cu 27 observed earlier …”

“…A puzzling observation was encountered when (Bu 4 N) 2 [CO 3 ⊂{Cu­(μ-OH)­(μ-pz)} 27 ] ( Cu 27 ), obtained by etching the (Bu 4 N) 2 [CO 3 ⊂{Cu­(μ-OH)­(μ-pz)} n ] ( n = 27, 29, 30, and 31) mixture with NH 3 , was purified by recrystallization from toluene by hexane vapor diffusion. To obtain a high-purity sample, the crystals were redissolved in toluene for a second recrystallization.…”

“…Once self-assembled, the nanojar wraps around the incarcerated anion using a multitude of hydrogen bonds and completely isolates it from the surrounding medium. Consequently, the anion (carbonate, sulfate, − phosphate, and arsenate) is bound extremely strongly, so that an aqueous Ba 2+ solution is unable to precipitate the corresponding highly insoluble barium salt (e.g., BaSO 4 ; K sp = 1.08 × 10 –10 ) when stirred with a solution of the nanojars. Owing to this exceptionally strong binding affinity, nanojars are able to transfer even the most hydrophilic anions, such as carbonate, from water into aliphatic solvents and have been developed into extraction agents for the removal of such anions from contaminated aqueous media by liquid–liquid extraction .…”

Pyrene-Functionalized Fluorescent Nanojars: Synthesis, Mass Spectrometric, and Photophysical Studies

“…Increasing temperatures lead to the sharpening of these peaks as the magnetic moment of the copper complex decreases and reveal a new peak at ∼34.0 ppm (Cu 9 -ring) at 50 °C which was too broad to be observable at 25 °C. As in the [CO 3 ⊂{Cu(OH)(pz)} n ] 2− (n = 27, 29) NJs studied before, 4,5 the pyrazole protons in the Cu 9 -ring of the Cu 27 NJ are the most sensitive to temperature changes as the corresponding peak shifts upfield by over 5 ppm units on going from 25 to 140 °C in a DMSO-d 6 solution. Meanwhile, the peaks corresponding to the Cu 6 -and Cu 12 -rings of the Cu 27 NJ, as well as the Cu 8 -and Cu 13 -rings of the Cu 29 NJ experience much smaller shifts of less than 0.6 ppm units.…”

“…A second column was performed on impure fractions using 49:1 CHCl 3 /MeOH to yield an additional 30 mg of HL2 (overall yield: 30%). 1 4 with details mentioned here. The fluorescent ligand (0.05 mmol) was combined with pyrazole (0.95 mmol) in a 1:19 ratio, respectively, to total 1 mmol in a round bottom flask.…”