TY - JOUR
T1 - Magnetic alignment and quadrupolar/paramagnetic cross-correlation in complexes of Na with LnDOTP 5-
AU - Eliav, Uzi
AU - Chandra Shekar, S.
AU - Ling, Wen
AU - Navon, Gil
AU - Jerschow, Alexej
N1 - Funding Information:
We acknowledge Dr. Hadassah Shinar for support in NMR measurements. This work was supported by Grants from: the US National Science Foundation, CHE 0957586, and US-Israel Binational Science Foundation no. 2007157.
PY - 2012/3
Y1 - 2012/3
N2 - The observation of a double-quantum filtered signal of quadrupolar nuclei (e.g. 23Na) in solution has been traditionally interpreted as a sign for anisotropic reorientational motion. Ling and Jerschow (2007) [23] have found that a 23Na double-quantum signal is observed also in solutions of TmDOTPNa 5. Interference effects between the quadrupolar and the paramagnetic interactions have been reported to lead to the appearance of double-quantum coherences even in the absence of a residual quadrupolar interaction. In addition, such processes lead to differential linebroadening effects between the satellite transitions, akin to effects that are well known for dipolar-CSA cross-correlation. Here, we report experiments on sodium in the presence of LnDOTP compounds, where it is shown that these cross-correlation effects correlate well with the pseudo-contact shift. In addition, anisotropic g-values of the lanthanide compounds in question, can also lead to alignment within the magnetic field, and consequently to the appearance of line splitting and double-quantum coherences. The two competing effects are demonstrated and it is concluded that both cross-correlated relaxation and alignment in the magnetic field must be at work in the systems described here.
AB - The observation of a double-quantum filtered signal of quadrupolar nuclei (e.g. 23Na) in solution has been traditionally interpreted as a sign for anisotropic reorientational motion. Ling and Jerschow (2007) [23] have found that a 23Na double-quantum signal is observed also in solutions of TmDOTPNa 5. Interference effects between the quadrupolar and the paramagnetic interactions have been reported to lead to the appearance of double-quantum coherences even in the absence of a residual quadrupolar interaction. In addition, such processes lead to differential linebroadening effects between the satellite transitions, akin to effects that are well known for dipolar-CSA cross-correlation. Here, we report experiments on sodium in the presence of LnDOTP compounds, where it is shown that these cross-correlation effects correlate well with the pseudo-contact shift. In addition, anisotropic g-values of the lanthanide compounds in question, can also lead to alignment within the magnetic field, and consequently to the appearance of line splitting and double-quantum coherences. The two competing effects are demonstrated and it is concluded that both cross-correlated relaxation and alignment in the magnetic field must be at work in the systems described here.
KW - Alignment of lanthanide complexes
KW - Cross-correlated relaxation
KW - LnDOTP
KW - Mulitple-quantum coherences
KW - Na lanthanide shift reagents
KW - Paramagnetic interaction
KW - Pseudocontact shifts
KW - Quadrupolar coupling
UR - http://www.scopus.com/inward/record.url?scp=84858342661&partnerID=8YFLogxK
U2 - 10.1016/j.jmr.2012.01.012
DO - 10.1016/j.jmr.2012.01.012
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AN - SCOPUS:84858342661
SN - 1090-7807
VL - 216
SP - 114
EP - 120
JO - Journal of Magnetic Resonance
JF - Journal of Magnetic Resonance
ER -