TY - JOUR
T1 - Carbonyl back-bonding influencing the rate of quantum tunnelling in a dysprosium metallocene single-molecule magnet
AU - Collins, Richard
AU - Heras Ojea, María José
AU - Mansikkamäki, Akseli
AU - Tang, Jinkui
AU - Layfield, Richard A.
PY - 2020/1/6
Y1 - 2020/1/6
N2 - The isocarbonyl-ligated metallocene coordination polymers [Cp*2M(μ-OC)W(Cp)(CO)(μ-CO)]∞ were synthesized with M = Gd (1, L = THF) and Dy (2, no L). In a zero direct-current field, the dysprosium version 2 was found to be a single-molecule magnet (SMM), with analysis of the dynamic magnetic susceptibility data revealing that the axial metallocene coordination environment leads to a large anisotropy barrier of 557(18) cm–1 and a fast quantum-tunnelling rate of ∼3.7 ms. Theoretical analysis of two truncated versions of 2, [Cp*2Dy{(μ-OC)W(Cp)(CO)2}2]− (2a), and [Cp*2Dy(OC)2]+ (2b), in which the effects of electron correlation outside the 4f orbital space were studied, revealed that tungsten-to-carbonyl back-donation plays an important role in determining the strength of the competing equatorial field at dysprosium and, hence, the dynamic magnetic properties. The finding that a classical organo-transition-metal bonding scenario can be used as an indirect way of tuning the rate of quantum tunnelling potentially provides an alternative chemical strategy for utilizing the fast magnetic relaxation properties of SMMs.
AB - The isocarbonyl-ligated metallocene coordination polymers [Cp*2M(μ-OC)W(Cp)(CO)(μ-CO)]∞ were synthesized with M = Gd (1, L = THF) and Dy (2, no L). In a zero direct-current field, the dysprosium version 2 was found to be a single-molecule magnet (SMM), with analysis of the dynamic magnetic susceptibility data revealing that the axial metallocene coordination environment leads to a large anisotropy barrier of 557(18) cm–1 and a fast quantum-tunnelling rate of ∼3.7 ms. Theoretical analysis of two truncated versions of 2, [Cp*2Dy{(μ-OC)W(Cp)(CO)2}2]− (2a), and [Cp*2Dy(OC)2]+ (2b), in which the effects of electron correlation outside the 4f orbital space were studied, revealed that tungsten-to-carbonyl back-donation plays an important role in determining the strength of the competing equatorial field at dysprosium and, hence, the dynamic magnetic properties. The finding that a classical organo-transition-metal bonding scenario can be used as an indirect way of tuning the rate of quantum tunnelling potentially provides an alternative chemical strategy for utilizing the fast magnetic relaxation properties of SMMs.
KW - isocarbonyl-ligated metallocene coordination polymers
KW - single-molecule magnet (SMM)
KW - anisotropy barrier
KW - electron correlation
UR - https://sussex.figshare.com/articles/journal_contribution/Carbonyl_back-bonding_influences_the_rate_of_quantum_tunnelling_in_a_dysprosium_metallocene_single-molecule_magnet/23475731
U2 - 10.1021/acs.inorgchem.9b02895
DO - 10.1021/acs.inorgchem.9b02895
M3 - Article
SN - 0020-1669
VL - 59
SP - 642
EP - 647
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 1
ER -