An Old Crystallization Technique as a Fast, Facile, and Adaptable Method for Obtaining Single Crystals of Unstable “Li2TCNQF4” and New Compounds of TCNQ or TCNQF4: Syntheses, Crystal Structures, and Magnetic Properties

Šterbinská, Slavomíra ; Holub, Mariia ; Cižmár, Erik ; Cernák, Juraj ; Falvello, Lawrence Rocco (Universidad de Zaragoza) ; Tomás, Milagros

Resumen: Detailed structural information is essential for understanding the properties of TCNQ and TCNQF4 compounds (TCNQ = 7,7,8,8-tetracyanoquinodimethane; TCNQF4 = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane). The ineludible requirement of obtaining crystals of a size and quality sufficient to yield a successful X-ray diffraction analysis has been challenging to satisfy because of the instability of many of these compounds in solution. Crystals of two new complexes of TCNQ, [trans-M(2ampy)2(TCNQ)2] [M = Ni (1), Zn (2); 2ampy = 2-aminomethylpyridine], as well as unstable [Li2(TCNQF4)(CH3CN)4]·CH3CN (3), can be prepared in minutes by a horizontal diffusion technique and can be harvested easily for X-ray structural studies. Compound 3, previously described as “Li2TCNQF4,” forms a one-dimensional (1D) ribbon. Compounds 1 and 2 can also be obtained as microcrystalline solids from methanolic solutions of MCl2/LiTCNQ/2ampy. Their variable-temperature magnetic studies confirmed a contribution of strongly antiferromagnetically coupled pairs of TCNQ•─ anion radicals at higher temperatures with exchange coupling J/kB = −1206 K and J/kB = −1369 K for 1 and 2, respectively, estimated using a spin dimer model. The presence of magnetically active anisotropic Ni(II) atoms with S = 1 in 1 was confirmed, and the magnetic behavior of 1, representing an infinite chain of alternating S = 1 sites and S = 1/2 dimers, was described by a spin-ring model suggesting ferromagnetic exchange coupling between Ni(II) sites and anion radicals.

Idioma: Inglés

DOI: 10.1021/acs.cgd.3c00160

Año: 2023

Publicado en: CRYSTAL GROWTH & DESIGN 23, 6 (2023), 4357-4369
ISSN: 1528-7483

Factor impacto JCR: 3.2 (2023)

Categ. JCR: CRYSTALLOGRAPHY rank: 5 / 33 = 0.152 (2023) - Q1 - T1
Categ. JCR: CHEMISTRY, MULTIDISCIPLINARY rank: 97 / 231 = 0.42 (2023) - Q2 - T2
Categ. JCR: MATERIALS SCIENCE, MULTIDISCIPLINARY rank: 201 / 439 = 0.458 (2023) - Q2 - T2

Factor impacto CITESCORE: 6.3 - Condensed Matter Physics (Q1) - Chemistry (all) (Q2) - Materials Science (all) (Q2)

Factor impacto SCIMAGO: 0.649 - Chemistry (miscellaneous) (Q2) - Materials Science (miscellaneous) (Q2) - Condensed Matter Physics (Q2)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E11-20R
Financiación: info:eu-repo/grantAgreement/ES/DGA/M4
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PID2021-124880NB-I00

Tipo y forma: Article (Published version)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)