Abstract
Using transition metal ions for spin-based applications, such as electron paramagnetic resonance imaging (EPRI) or quantum computation, requires a clear understanding of how local chemistry influences spin properties. Herein we report a series of four ionic complexes to provide the first systematic study of one aspect of local chemistry on the V(iv) spin-the counterion. To do so, the four complexes (Et 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (1), (n-Bu 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (2), (n-Hex 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (3), and (n-Oct 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (4) were probed by EPR spectroscopy in solid state and solution. Room temperature, solution X-band (ca. 9.8 GHz) continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy revealed an increasing linewidth with larger cations, likely a counterion-controlled tumbling in solution via ion pairing. In the solid state, variable-temperature (5-180 K) X-band (ca. 9.4 GHz) pulsed EPR studies of 1-4 in o-terphenyl glass demonstrated no effect on spin-lattice relaxation times (T 1 ), indicating little role for the counterion on this parameter. However, the phase memory time (T m ) of 1 below 100 K is markedly smaller than those of 2-4. This result is counterintuitive, as 2-4 are relatively richer in 1 H nuclear spin, hence, expected to have shorter T m . Thus, these data suggest an important role for counterion methyl groups on T m , and moreover provide the first instance of a lengthening T m with increasing nuclear spin quantity on a molecule.
| Original language | English |
|---|---|
| Pages (from-to) | 548-555 |
| Number of pages | 8 |
| Journal | Chemical Science |
| Volume | 10 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2019 Jan 1 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
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Counterion influence on dynamic spin properties in a V(iv) complex. / Lin, Chun-Yi; Ngendahimana, Thacien; Eaton, Gareth R.; Eaton, Sandra S.; Zadrozny, Joseph M.
In: Chemical Science, Vol. 10, No. 2, 01.01.2019, p. 548-555.Research output: Contribution to journal › Article
TY - JOUR
T1 - Counterion influence on dynamic spin properties in a V(iv) complex
AU - Lin, Chun-Yi
AU - Ngendahimana, Thacien
AU - Eaton, Gareth R.
AU - Eaton, Sandra S.
AU - Zadrozny, Joseph M.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Using transition metal ions for spin-based applications, such as electron paramagnetic resonance imaging (EPRI) or quantum computation, requires a clear understanding of how local chemistry influences spin properties. Herein we report a series of four ionic complexes to provide the first systematic study of one aspect of local chemistry on the V(iv) spin-the counterion. To do so, the four complexes (Et 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (1), (n-Bu 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (2), (n-Hex 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (3), and (n-Oct 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (4) were probed by EPR spectroscopy in solid state and solution. Room temperature, solution X-band (ca. 9.8 GHz) continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy revealed an increasing linewidth with larger cations, likely a counterion-controlled tumbling in solution via ion pairing. In the solid state, variable-temperature (5-180 K) X-band (ca. 9.4 GHz) pulsed EPR studies of 1-4 in o-terphenyl glass demonstrated no effect on spin-lattice relaxation times (T 1 ), indicating little role for the counterion on this parameter. However, the phase memory time (T m ) of 1 below 100 K is markedly smaller than those of 2-4. This result is counterintuitive, as 2-4 are relatively richer in 1 H nuclear spin, hence, expected to have shorter T m . Thus, these data suggest an important role for counterion methyl groups on T m , and moreover provide the first instance of a lengthening T m with increasing nuclear spin quantity on a molecule.
AB - Using transition metal ions for spin-based applications, such as electron paramagnetic resonance imaging (EPRI) or quantum computation, requires a clear understanding of how local chemistry influences spin properties. Herein we report a series of four ionic complexes to provide the first systematic study of one aspect of local chemistry on the V(iv) spin-the counterion. To do so, the four complexes (Et 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (1), (n-Bu 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (2), (n-Hex 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (3), and (n-Oct 3 NH) 2 [V(C 6 H 4 O 2 ) 3 ] (4) were probed by EPR spectroscopy in solid state and solution. Room temperature, solution X-band (ca. 9.8 GHz) continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy revealed an increasing linewidth with larger cations, likely a counterion-controlled tumbling in solution via ion pairing. In the solid state, variable-temperature (5-180 K) X-band (ca. 9.4 GHz) pulsed EPR studies of 1-4 in o-terphenyl glass demonstrated no effect on spin-lattice relaxation times (T 1 ), indicating little role for the counterion on this parameter. However, the phase memory time (T m ) of 1 below 100 K is markedly smaller than those of 2-4. This result is counterintuitive, as 2-4 are relatively richer in 1 H nuclear spin, hence, expected to have shorter T m . Thus, these data suggest an important role for counterion methyl groups on T m , and moreover provide the first instance of a lengthening T m with increasing nuclear spin quantity on a molecule.
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U2 - 10.1039/c8sc04122a
DO - 10.1039/c8sc04122a
M3 - Article
AN - SCOPUS:85059577776
VL - 10
SP - 548
EP - 555
JO - Chemical Science
JF - Chemical Science
SN - 2041-6520
IS - 2
ER -