Developments of NMR - From Molecules to Human Behaviour and Beyond

NMR has made rapid progress in the last more than seven decades after its discovery. This article reviews the development of this field over the years with emphasis on some of the recent developments with interesting consequences for the study of mental health and human behaviour

Unidentate coordination of 2,2â²-bipyridine and 1,10-phenanthroline in a cyclometallated rhodium(III) complex. Evidence from 1H and 13C NMR spectra

The binuclear cyclometallated complex RhCl(μ-Cl)(bBzlH2bz)2 bBzlH2bzH = 1,3-bis(benzimidazolyl)benzene undergoes a dichloro bridge cleavage reaction with 2,2â²-bipyridine (bipy) or 1,10-phenanthroline (phen) in the presence of perchlorate to yield a mononuclear complex of the type RhCl(OClO3)(bBzlH2bz)(N-N) (N-N = bipy or phen). Surprisingly, the N-heterocycle, bipy or phen, is neither chelating nor bridging bidentate in the complex. Such a monodentate coordination of bipy or phen was detected using two-dimensional 1H-1H correlated and NOE experiments (DQF-COSY and ROESY), 1H-13C single-and multiple-bond correlated two-dimensional NMR experiments (PFG-HSQC and PFG-HMBC) and 1H,13C spin-lattice relaxation time measurements. The non-coordination of the pendant nitrogen of the heterocycle bipy or phen is evidenced by the observation of two sets of signals together with the presence of interligand NOEs only between the coordinated part of the heterocycle and the bisbenzimidazole as seen in the corresponding ROESY spectrum. Further, the 1H and 13C spin-lattice relaxation times show lower values for the nuclei in the coordinated part of the heterocycle, bipy or phen, than for the uncoordinated parts, supporting the fact that only one of the two nitrogens of the heterocycle has coordinated to the metal and thus behaves as monodentate ligand. Copyright © 2000 John Wiley & Sons, Ltd

Synthesis and NMR spectral assignments of novel nitrogen and sulfur heterocyclic compounds

Synthesis and NMR spectral studies of multidentate N and S heterocycles, 1,3,5-tris(N-methylbenzimidazolyl)benzene, 1,3,5-tris(benzimidazolyl)benzene,1, 3,5-tris(benzothiazolyl) benzene, 2,2â²-bipyridine 3,3â²- bis(benzothiazolyl)benzene and 1,2,4,5-tetrakis(benzothiazolyl) benzene have been carried out. 2D 1H-1H PFG-COSY as well as 1H-13C single and multiple bond correlated (2D GRASP-HSQC and GRASP-HMBC) experiments have been employed to characterize the compounds. 1D NOE experiments have been useful in understanding the structure of 1,3,5-tris(N-methylenzimidazolyl)benzene. Copyright © 2008 John Wiley & Sons, Ltd

Quantum-information processing by nuclear magnetic resonance: experimental implementation of half-adder and subtractor operations using an oriented spin-7/2 system

The advantages of using quantum systems for performing many computational tasks have already been established. Several quantum algorithms have been developed which exploit the inherent property of quantum systems such as superposition of states and entanglement for efficiently performing certain tasks. The experimental implementation has been achieved on many quantum systems, of which nuclear magnetic resonance has shown the largest progress in terms of number of qubits. This paper describes the use of a spin-7/2 as a three-qubit system and experimentally implements the half-adder and subtractor operations. The required qubits are realized by partially orienting Cs-133 nuclei in a liquid-crystalline medium, yielding a quadrupolar split well-resolved septet. Another feature of this paper is the proposal that labeling of quantum states of system can be suitably chosen to increase the efficiency of a computational task

Quantum information processing by NMR using strongly coupled spins

The enormous theoretical potential of quantum information processing (QIP) is driving the pursuit for its practical realization by various physical techniques. Currently, nuclear magnetic resonance (NMR) has been the forerunner by demonstrating a majority of quantum algorithms. In NMR, spin-systems consisting of coupled nuclear spins are utilized as qubits. In order to carry out QIP, a spin-system has to meet two major requirements: (i) qubit addressability and (ii) mutual coupling among the. qubits. It has been demonstrated that the magnitude of the mutual coupling among qubits can be increased by orienting the spin-systems in a liquid crystal matrix and utilizing the residual dipolar couplings. While utilizing residual dipolar couplings may be useful to increase the number of qubits, nuclei of the same species (homonuclei) might become strongly coupled. In strongly coupled spin-systems, spins lose their individual identity of being qubits. We propose that even such strongly coupled spin-systems can be used for QIP and the qubit-manipulation can be achieved by transition-selective pulses. We demonstrate experimental preparation of pseudopure states, creation of maximally entangled states, implementation of logic gates and implementation of Deutsch-Jozsa (DJ) algorithm in strongly coupled 2, 3 and 4 spin-systems. The energy levels of the strongly coupled 3 and 4 spin-systems were obtained using a Z-COSY experiment