TY - JOUR

T1 - cis Versus trans-Azobenzene

T2 - Precise Determination of NMR Parameters and Analysis of Long-Lived States of 15N Spin Pairs

AU - Sheberstov, Kirill F.

AU - Vieth, Hans Martin

AU - Zimmermann, Herbert

AU - Ivanov, Konstantin L.

AU - Kiryutin, Alexey S.

AU - Yurkovskaya, Alexandra V.

PY - 2018/3/1

Y1 - 2018/3/1

N2 - We provide a detailed evaluation of nuclear magnetic resonance (NMR) parameters of the cis- and trans-isomers of azobenzene (AB). For determining the NMR parameters, such as proton–proton and proton–nitrogen J-couplings and chemical shifts, we compared NMR spectra of three different isotopomers of AB: the doubly 15N labeled azobenzene, 15N,15N′-AB, and two partially deuterated AB isotopomers with a single 15N atom. For the total lineshape analysis of NMR spectra, we used the recently developed ANATOLIA software package. The determined NMR parameters allowed us to optimize experiments for investigating singlet long-lived spin states (LLSs) of 15N spin pairs and to measure LLS lifetimes in cis-AB and trans-AB. Magnetization-to-singlet-to-magnetization conversion has been performed using the SLIC and APSOC techniques, providing a degree of conversion up to 17 and 24% of the initial magnetization, respectively. Our approach is useful for optimizing the performance of experiments with singlet LLSs; such LLSs can be exploited for preserving spin hyperpolarization, for probing slow molecular dynamics, slow chemical processes and also slow transport processes.

AB - We provide a detailed evaluation of nuclear magnetic resonance (NMR) parameters of the cis- and trans-isomers of azobenzene (AB). For determining the NMR parameters, such as proton–proton and proton–nitrogen J-couplings and chemical shifts, we compared NMR spectra of three different isotopomers of AB: the doubly 15N labeled azobenzene, 15N,15N′-AB, and two partially deuterated AB isotopomers with a single 15N atom. For the total lineshape analysis of NMR spectra, we used the recently developed ANATOLIA software package. The determined NMR parameters allowed us to optimize experiments for investigating singlet long-lived spin states (LLSs) of 15N spin pairs and to measure LLS lifetimes in cis-AB and trans-AB. Magnetization-to-singlet-to-magnetization conversion has been performed using the SLIC and APSOC techniques, providing a degree of conversion up to 17 and 24% of the initial magnetization, respectively. Our approach is useful for optimizing the performance of experiments with singlet LLSs; such LLSs can be exploited for preserving spin hyperpolarization, for probing slow molecular dynamics, slow chemical processes and also slow transport processes.

KW - FIELD

KW - PHOTOISOMERIZATION

KW - RELAXATION

KW - SINGLET ORDER

KW - SPECTRA

KW - TOTAL LINESHAPE ANALYSIS

UR - http://www.scopus.com/inward/record.url?scp=85038636381&partnerID=8YFLogxK

U2 - 10.1007/s00723-017-0968-8

DO - 10.1007/s00723-017-0968-8

M3 - Article

C2 - 29479146

AN - SCOPUS:85038636381

VL - 49

SP - 293

EP - 307

JO - Applied Magnetic Resonance

JF - Applied Magnetic Resonance

SN - 0937-9347

IS - 3

ER -