tyrosinase is a multifunctional copper-containing enzyme. it can catalyze two distinct reactions of melanin synthesis and benzaldehyde derivatives, which are potential tyrosinase inhibitors.  to find the relationships between charge distributions of benzaldehyde and their pharmaceutical behavior, the present study aimed at investigating nuclear quadrupole coupling constants of quadrupolare nucl...

Residual dipolar couplings between spin-1/2 and quadrupolar nuclei are often observed and exploited in the magic-angle spinning (MAS) NMR spectra of spin-1/2 nuclei. These orientation-dependent splittings contain information on the dipolar interaction, which can be translated into structural information. The same type of splittings may also be observed for pairs of quadrupolar nuclei, although ...

Recent advances in nuclear magnetic resonance (NMR) methodology and improvements in high-field NMR instrumentation have generated a new wave of research interests in the application of solid-state NMR to the study of quadrupolar nuclei. These developments now permit increasingly complex biological systems to be probed by quadrupolar NMR. In this review I describe a few recent developments in NM...

Historically, cross-polarization experiments [1,2] have been used to transfer spin coherence from abundant spins to a dilute spin system. Protons (*H) have been used almost exclusively as the source of strong nuclear polarization for cross-polarization experiments, although there have been some examples where other abundant nuclei have been used. Coupled with magic-angle spinning (MAS) NMR [3],...

The theory describing homonuclear indirect nuclear spin-spin coupling (J) interactions between pairs of quadrupolar nuclei is outlined and supported by numerical calculations. The expected first-order multiplets for pairs of magnetically equivalent (A2), chemically equivalent (AA'), and non-equivalent (AX) quadrupolar nuclei are given. The various spectral changeovers from one first-order multi...

An enhanced Rotor Assisted Population Transfer (RAPT) experiment is presented and used as a simple and fast technique to measure the magnitude of the nuclear quadrupolar coupling constant of half-integer quadrupolar nuclei. The enhanced RAPT sequence consists of a train of Gaussian pulses with alternating off-resonant frequencies of +/-nuoff. Simulated and experimental results demonstrating the...

Magic echo cycles are introduced for performing quadrupolar echo spectroscopy of spin-1 nuclei. An analysis is performed via average Hamiltonian theory showing that the evolution under chemical shift or static field inhomogeneity can be refocused simultaneously with the quadrupolar interaction using these cycles. Due to the higher convergence in the Magnus expansion, with sufficient RF power, m...

Selective reintroduction of anisotropic interactions such as the chemical shift anisotropy (CSA) and homonucler dipolar (HMD) coupling were implemented in a high-resolution NMR spectroscopy for half-integer quadrupolar nuclei. Rotary resonance recoupling (R(3)) combined with the multiple-quantum magic-angle spinning (MQMAS) in a three-dimensional (3D) experiment provides not only site-specific ...

Among the interactions which govern NMR spectra, spin-spin coupling interactions provide the most direct form of structural information which is of interest to chemists. Dipolar coupling may be used to measure internuclear distances directly and J coupling may be used to identify bonding interactions and provide insights into the nature of the bonds. It is well known that the presence of a quad...

This thesis reports on the development of new methods for studying spin > 1/2 nucleiin solids using nuclear magnetic resonance (NMR), and the application of these and othersolid-state NMR techniques to probing local structure in biological solids.The need to improve solid state NMR methods for quadrupolar nuclei, with emphasison applications to biopolymers, is motivated in Chapt...