title: Magnetic alignment and quadrupolar/paramagnetic cross-correlation in complexes of Na with LnDOTP5-.
abstract: The observation of a double-quantum filtered signal of quadrupolar nuclei (e.g. (23)Na) in solution has been traditionally interpreted as a sign for anisotropic reorientational motion. Ling and Jerschow (2007) have found that a (23)Na 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.
authors.affiliation: School of Chemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
authors.forename: Uzi
authors.initials: U
authors.lastname: Eliav
authors.forename: S Chandra
authors.initials: SC
authors.lastname: Shekar
authors.forename: Wen
authors.initials: W
authors.lastname: Ling
authors.forename: Gil
authors.initials: G
authors.lastname: Navon
authors.forename: Alexej
authors.initials: A
authors.lastname: Jerschow
mesh_terms: D000465:Algorithms; D016880:Anisotropy; D004574:Electromagnetic Fields; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D007811:Lanthanum / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D010080:Oxazoles / Q000737:chemistry*; D011744:Pyrimidinones / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D013757:Tetraethylammonium Compounds / Q000737:chemistry
chemical_list: D010080:Oxazoles; D011744:Pyrimidinones; D012996:Solutions; D013757:Tetraethylammonium Compounds; C063359:2,3-dihydro-5H-oxazolo(3,2-a)thieno(3,2-d)pyrimidin-5-one; D007811:Lanthanum; D012964:Sodium