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Modern applications of NMR spectroscopy: Heteronuclei

Vorlesung WS 2019/20

 

(1) General overview

NMR-PTE, index, active spins, c.s. trends, c.s. ranges (1), c.s. ranges (2),  2nd order coupling (1), 2nd order coupling (2), BH4 spin system, B2H4Me2 spin system, chemical shift ranges (I 1/2), c.s. ranges (I > 1/2), c.s. referencing (Xi scale), c.s. B-11, c.s. N-14/15, c.s. P-31, receptivity of X nuclei, 'practicability' of X nuclei, relaxation (N-14), influence I on linewidth, literature.

(2) Methods and physical background

Detection modes for X nuclear acquisition, INEPT experiment, signal enhancement (NOE vs. INEPT, NOE vs. INEPT (2)), heteronuclear NOE, sensitivity of methods, heteronuclear COSY, 3D methods, suppression of acoustic ringing, lineshape for quadrupolar nuclei, choice of experiment, diffusion-ordered NMR (DOSY),  INADEQUATE, PHIP for intermediates, solid state (distances), literature.

(3) Heteronuclei (part 1)

Spin 1/2 nuclei (selected list), suitable/intermediate/tricky (selection), N-15 example, Rh-103 example, Ag-109/107 example, Pt-195 example

(4) Heteronuclei (part 2)

Quadrupolar nuclei (selected list), suitable/intermediate/tricky (selection), Li-6 (1D NOE), Li-6 (HOESY), Be-9 example, B-11 example, Ti-49/47 example, Co-59 (c.s. vs. ligand field, structure-activity relation), V-51 (chemical shift range), Al-27 (influence of symmetry)

(5) Paramagnetism

Comparison diamagnetic vs. paramagnetic parameters, pseudocontact shift (PCS), Lanthanide-induces shift (LIS), a paramagnetic balance, BioNMR: paramagnetic relaxation enhancement (PRE)

(6) Applications - coordination chemistry

Dynamics in NMR: lineshape of NMR spectra (regimes of NMR timescale, lineshape and rate constant, non-symmetric case), Na-23 (exchange in slow regime), O-17 (exchange with v.t. NMR), P-31 (ligand exchange with v.t. NMR), saturation transfer (Os COD complex

(7) Applications - organometallic chemistry

Diffusion for size determination: principle of gradient spin echo experiment (PGSE), DOSY example

(8) Applications - bioinorganic, biology

Heteronuclei in biochemistry, spin I=1/2 - overview, examples: Cd-113 (general, application), I>1/2 - overview, examples: Al-27, Co-59

(9) Extra: Xe-129 NMR for sensing and imaging

Chemical shift, investigation of zeolites, hp-Xe in biosensing, literature last two classes