TY - JOUR
T1 - Alkyl-substituted Schlenk hydrocarbon diradicals with triplet and singlet ground states in frozen solutions
AU - Rajca, Andrzej
AU - Rajca, Suchada
PY - 1998/5
Y1 - 1998/5
N2 - Ground states for alkyl-substituted Schlenk hydrocarbon diradicals 1-4 in frozen 2-MeTHF or THF are determined at low temperatures by EPR spectroscopy (4-80 K) or SQUID magnetometry (2-80 K). Diradicals 1, 2, and 3 are triplet ground states. Diradical 4 is the singlet ground state with the singlet-triplet gap, ΔEST ≈ -0.2 kcal mol-1. Another minor diradical present in the samples of 4 possesses ΔEST ≈ -0.02 kcal mol-1; most likely, this diradical corresponds to another conformational isomer of 4. Compound 4 is the first hydrocarbon diradical with antiferromagnetic coupling through 1,3-phenylene, a ubiquitous mediator of a ferromagnetic coupling.
AB - Ground states for alkyl-substituted Schlenk hydrocarbon diradicals 1-4 in frozen 2-MeTHF or THF are determined at low temperatures by EPR spectroscopy (4-80 K) or SQUID magnetometry (2-80 K). Diradicals 1, 2, and 3 are triplet ground states. Diradical 4 is the singlet ground state with the singlet-triplet gap, ΔEST ≈ -0.2 kcal mol-1. Another minor diradical present in the samples of 4 possesses ΔEST ≈ -0.02 kcal mol-1; most likely, this diradical corresponds to another conformational isomer of 4. Compound 4 is the first hydrocarbon diradical with antiferromagnetic coupling through 1,3-phenylene, a ubiquitous mediator of a ferromagnetic coupling.
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U2 - 10.1039/a706374a
DO - 10.1039/a706374a
M3 - Article
AN - SCOPUS:0001543745
SN - 1470-1820
SP - 1077
EP - 1082
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
IS - 5
ER -