TY - JOUR
T1 - Synthesis and Magneto-Structural Study of Distorted Octahedral CoII Complexes with Picolinamide and Azide (μ1,1)-Bridge
AU - Pastor-Ramírez, Cándida
AU - Zamorano-Ulloa, Rafael
AU - Vazquez-Lima, Hugo
AU - Hernández-Anzaldo, Samuel
AU - Reyes-Ortega, Yasmi
N1 - Publisher Copyright:
© 2021 Wiley-VCH GmbH
PY - 2021/2/17
Y1 - 2021/2/17
N2 - Two compounds [Co2(pa)2(μ1,1-N3)2]n (1) and [Co4(pa)6(μ1,1-N3)6] (2), (pa=picolinamide) were obtained and studied by electronic and magnetic spectroscopies. 1 is a polymer and 2 is a tetramer of mixed-valence CoII/III. The N3− anions act as bridges between cobalt ions in the μ1,1 coordination mode. UV-Vis spectrum analysis showed the octahedral distortion of the compounds. ESR solution spectra revealed a low-spin ground state, s=1/2 ((Formula presented.)) for CoII. The energy gap was J> (Formula presented.) between levels, (Formula presented.) to (Formula presented.), of 2; consequently, its transition would not be observed. 1 showed zero-field splitting of the excited level (Formula presented.) with D∼0.31 cm−1. Hyperfine (59Co, I=7/2) and superhyperfine (14N, I=1) couplings were observed. Magnetic susceptibility studies (3–300 K) revealed antiferromagnetic exchange interactions in 1 and 2 with exchange coupling constants, J1=−108 cm−1 and J2=−20 cm−1, g=2 and s= (Formula presented.), for the Co(2)-Co(2) magnetic exchange pathways.
AB - Two compounds [Co2(pa)2(μ1,1-N3)2]n (1) and [Co4(pa)6(μ1,1-N3)6] (2), (pa=picolinamide) were obtained and studied by electronic and magnetic spectroscopies. 1 is a polymer and 2 is a tetramer of mixed-valence CoII/III. The N3− anions act as bridges between cobalt ions in the μ1,1 coordination mode. UV-Vis spectrum analysis showed the octahedral distortion of the compounds. ESR solution spectra revealed a low-spin ground state, s=1/2 ((Formula presented.)) for CoII. The energy gap was J> (Formula presented.) between levels, (Formula presented.) to (Formula presented.), of 2; consequently, its transition would not be observed. 1 showed zero-field splitting of the excited level (Formula presented.) with D∼0.31 cm−1. Hyperfine (59Co, I=7/2) and superhyperfine (14N, I=1) couplings were observed. Magnetic susceptibility studies (3–300 K) revealed antiferromagnetic exchange interactions in 1 and 2 with exchange coupling constants, J1=−108 cm−1 and J2=−20 cm−1, g=2 and s= (Formula presented.), for the Co(2)-Co(2) magnetic exchange pathways.
KW - Analytical methods
KW - Ascorbic acid
KW - Poly(methacrylic acid)
KW - Sensors
KW - Silver nanoclusters
UR - http://www.scopus.com/inward/record.url?scp=85101274596&partnerID=8YFLogxK
U2 - 10.1002/slct.202004323
DO - 10.1002/slct.202004323
M3 - Artículo
AN - SCOPUS:85101274596
SN - 2365-6549
VL - 6
SP - 1394
EP - 1403
JO - ChemistrySelect
JF - ChemistrySelect
IS - 7
ER -