TY - JOUR

T1 - Synthesis, Structural Versatility, Magnetic Properties, and I- Adsorption in a Series of Cobalt(II) Metal-Organic Frameworks with a Charge-Neutral Aliphatic (O,O)-Donor Bridge

AU - Abasheeva, Ksenia D

AU - Demakov, Pavel A

AU - Polyakova, Evgeniya V

AU - Lavrov, Alexander N

AU - Fedin, Vladimir P

AU - Dybtsev, Danil N

N1 - The research was funded by the Russian Science Foundation, project No. 22-23-20179, https://rscf.ru/en/project/22-23-20179/ (accessed on 13 October 2023), and the Government of the Novosibirsk Region, project No. p-22.

PY - 2023/10/16

Y1 - 2023/10/16

N2 - Four new metal-organic frameworks based on cobalt(II) salts and 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide (odabco) were obtained. Their crystallographic formulae are [Co3(odabco)2(OAc)6] (1, OAc- = acetate), [Co(H2O)2(HCOO)2]·odabco (2), [Co2(H2O)(NO3)(odabco)5](NO3)3·3.65H2O (3), and [Co2(DMF)2(odabco)4](NO3)4·3H2O (4; DMF = N,N-dimethylformamide). Crystal structures of 1-4 were determined by single-crystal X-ray crystallography. Coordination polymer 1 comprises binuclear and mononuclear metal-acetate blocks alternating within uncharged one-dimensional chains, in which odabco acts as a bridging ligand. A layered Co(II) formate 2 contains odabco only as guest molecules located in the interlayer space. Layered compound 3 and three-dimensional 4 have cationic coordination frameworks with 26% and 34% specific void volumes, respectively, unveiling high structural diversity of Co(II)-odabco MOFs based on quite a rare aliphatic moiety. Magnetization measurements were performed for 1, 3, and 4 and the obtained data were interpreted on the basis of their crystal structures. A strong (J/kB~100 K) antiferromagnetic coupling was found within binuclear metal blocks in 1. Ion exchange experiments revealed a considerable iodide uptake by 3 resulting in an up to 75% guest nitrate substitution within the voids of a coordination framework, found by capillary zone electrophoresis data and confirmed by single-crystal XRD. A preservation of 3 crystallinity during the exchange allowed for the guest I- positions within a new adduct with the formula [Co2(H2O)(NO3)(odabco)5]I2(NO3)·1.85H2O (3-I) to be successfully determined and the odabco aliphatic core to be revealed as a main adsorption center for quite large and easily polarizable iodide anions. In summary, this work presents a comprehensive study for a series of 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide-based MOFs of cobalt(II) within the framework of magnetic properties and reports the first example of anion exchange in odabco-based coordination networks, supported by direct X-ray structural data. The reported results unveil promising applications of such frameworks bearing ligands with an aliphatic core in the diverse structural design of selective adsorbents and other types of functional materials.

AB - Four new metal-organic frameworks based on cobalt(II) salts and 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide (odabco) were obtained. Their crystallographic formulae are [Co3(odabco)2(OAc)6] (1, OAc- = acetate), [Co(H2O)2(HCOO)2]·odabco (2), [Co2(H2O)(NO3)(odabco)5](NO3)3·3.65H2O (3), and [Co2(DMF)2(odabco)4](NO3)4·3H2O (4; DMF = N,N-dimethylformamide). Crystal structures of 1-4 were determined by single-crystal X-ray crystallography. Coordination polymer 1 comprises binuclear and mononuclear metal-acetate blocks alternating within uncharged one-dimensional chains, in which odabco acts as a bridging ligand. A layered Co(II) formate 2 contains odabco only as guest molecules located in the interlayer space. Layered compound 3 and three-dimensional 4 have cationic coordination frameworks with 26% and 34% specific void volumes, respectively, unveiling high structural diversity of Co(II)-odabco MOFs based on quite a rare aliphatic moiety. Magnetization measurements were performed for 1, 3, and 4 and the obtained data were interpreted on the basis of their crystal structures. A strong (J/kB~100 K) antiferromagnetic coupling was found within binuclear metal blocks in 1. Ion exchange experiments revealed a considerable iodide uptake by 3 resulting in an up to 75% guest nitrate substitution within the voids of a coordination framework, found by capillary zone electrophoresis data and confirmed by single-crystal XRD. A preservation of 3 crystallinity during the exchange allowed for the guest I- positions within a new adduct with the formula [Co2(H2O)(NO3)(odabco)5]I2(NO3)·1.85H2O (3-I) to be successfully determined and the odabco aliphatic core to be revealed as a main adsorption center for quite large and easily polarizable iodide anions. In summary, this work presents a comprehensive study for a series of 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide-based MOFs of cobalt(II) within the framework of magnetic properties and reports the first example of anion exchange in odabco-based coordination networks, supported by direct X-ray structural data. The reported results unveil promising applications of such frameworks bearing ligands with an aliphatic core in the diverse structural design of selective adsorbents and other types of functional materials.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85175029488&origin=inward&txGid=c947d149bbb1fb68903cfbdc1df50ae8

U2 - 10.3390/nano13202773

DO - 10.3390/nano13202773

M3 - Article

C2 - 37887924

VL - 13

JO - Nanomaterials

JF - Nanomaterials

SN - 2079-4991

IS - 20

M1 - 2773

ER -