Nuclear Magnetic Resonance Spectroscopy

BY B.E. MANN

1 Introduction

Following the criteria established in earlier volumes, only books and reviews directly relevant to this chapter are included and the reader who requires a complete list is referred to the Specialist Periodical Reports 'Nuclear Magnetic Resonance', where a complete list of books and reviews is given. Reviews which are of direct relevance to a section of this report are included in the beginning of that section rather than here. Papers where only 1, 2H, 13C, 19F and/or 31P NMR spectroscopy is used are only included when they make a non-routine contribution, but complete coverage of relevant papers is still attempted where nuclei other than these are involved. In view of the greater restrictions on space and the ever growing number of publications, many more papers in marginal areas have been omitted. This is especially the case in the sections on solid-state NMR spectroscopy, silicon and phosphorus.

A number of reviews have also been published: 'NMR in metals, metal particles and metal clusters' which contains 55Mn, 63Cu, 65Cu, 105Pd, 107Ag, 109Ag, 111Cd, 113Cd, 195Pt and 197Au NMR data, Tris(pyrazolyl)methane ligands: the neutral analogues of tris(pyrazolyl)borate ligands', which contains 113Cd NMR data, 'NMR spectroscopy of quadrupole nuclei in supercritical fluids', and 'Enantioselective homogeneous catalysis: transferring chirality via phosphine complexes. A 2D NMR approach'.

A number of papers have been published which are too broadly based to fit into a later section and are included here. Indirect spin–spin coupling tensors have been calculated for diatomic molecules such as LiH, KNa and HC1 and compared with experiment. The influence of metal cation complexation on six different esters of ethylene glycol has been studied using 1H, 7Li, 11B, 13C, 17O, 13P and 87Rb NMR spectroscopy. Radiofrequency-mediated dipolar recou-pling among half-integer quadrupolar spins has been investigated for 23Na2. The binding of Mg2+, Mn2+ and [Co(NH3) 6]3+ to hairpin ribozyme domains has been determined by NMR spectroscopy. Density functional calculations of shielding have been applied to 13C, 17O, 51V, 53Cr, 55Mn, 57Fe, 59Co and 61Ni chemical shifts in [VOC13], [VF5], [Cr(CO)6], [CrO4]2-, [Mn(CO)6]+, [MnO4]-, [Fe(CO)5], [(η 5-C5H5)Fe], [FeO4], [Co(CN)6]3-, [Co(NH3)]3+ and [Ni(CO)4]. Relativistic effects for NMR shielding constants have been calculated for 53Cr, 55Mn, 57Fe, 95Mo, 99Tc, 99Ru, 183W, 187Re and 189Os in [MO4]n- and [M(CO)6], M = Cr, Mo, W. The symmetry of metal complexes has been studied using 13C isotope shifts. Pulse field gradient spin-echo measurements have been used to determine molecular diffusion in organo-metallic chemistry. 1H, 11B, 13C and 17O NMR spectroscopy has been used to study the complexation of CoCl2, NiCl2 and CuCl2 salts with three tris(oxaalkyl) borates. One-bond nuclear spin–spin coupling constants involving 183W, 195Pt, 199Hg and207Pb have been calculated using relativistic corrections. The coupling constants and anisotropies of XF, X = C1, Br, I and T1X, X = F, Cl, Br, I, have been calculated and the paper contains 35C1, 37C1, 79Br, 81Br, 127I, 203Tl and 205Tl data. The shielding polarizabilities of H2O2, F2, HC=CH, H2CO, NH3, HCN and HNC have been calculated.

2 Stereochemistry

This section is subdivided into eleven parts which contain NMR information about Groups 1 and 2 and transition-metal complexes presented by Groups according to the Periodic Table. Within each Group, classification is by ligand type.

2.1 Complexes of Groups 1 and 2. – Two reviews, entitled 'Applications of 7Li NMR in biomedicine' and 'In vivo imaging of the pharmacodynamics and pharmacokinetics of lithium', have appeared.

Diffusion-ordered NMR spectroscopy (DOSY) of THF solvated n-butyl-lithium aggregates has been reported and 1H and 7Li NMR spectroscopy has been used to identify a dimer and a tetramer. 1H-66Li HOESY has been used to investigate ion pairing in compounds such as [(Me3SiCH2)2CuLi]. 1J(13C(13C) and J(13 C(1H) have been determined in 2-lithiothiophene, 2-lithio-N-methylpyrrole and 2-lithiofuran. The 6Li chemical shift in (1) is at δ - 5.07 and has been attributed to the ring current. The solution structures of {(amino)phenylsilyl}lithiums have been investigated by 7Li, 13C, 15N and 29Si NMR spectroscopy and J(29Si7Li) and J(29Si15N) observed. NMR data have also been reported for [Li(THF)2(μ-H)AlH(SiMe3) (μ-H)AlH(SiMe3)H], (6Li, 27A1, 29Si), [(pmdta)LiCH2SPh], (6Li), [Ph2Si(CH2M)CH2N(CH2 -CH2OMe) 2], (M = Li, SnBu3; 6Li, 29Si, 199Sn), (2), (6Li, 15N), [Me-N(CH2)4C HLi], (6Li, 15N), Et α-lithioisobutyrate, (6Li), [(R1O)R22 Si-CHLiSiMe3], (6Li), (3), (11B), [Li(THF)2{Al[C(SiMe3)3] (SMe)3}], (7Li, 27Al, 29Si), [LiC(SiMe2CH2PPh2)3], (7Li, 29Si), (4), (7Li, 29Si), [Me2MC-(MXMe2)(SiMe3)2CLi (SiMe3)2], (M = Si, Ge, Sn; 29Si), [Li(2-C6H4PPh2-NSiMe3)] 2, [Sn(2-C6H4PPh2 -NSiMe3)2], (7Li, 29Si, 119Sn), [PhC=CLiBF3], (6Li, 11B), [H2C=CMeCH2NEtC9 H6Li], (15N), [{Li(tmen)}2 {3-(η3-C3H3SiR13-1)2SiR22], (7Li), (5), (7Li, 29Si), (6), (7Li, 29Si), [(Me3Si)3 Si-(Me2Si)2 (Me3Si)2SiLi], (29Si), (7), (7Li, 29Si), [(THF)Li3{Si(NPri)3 (NHPri)}] 2, (7Li, 29Si), and [ButSi(OSiMe2NPh)3GeLi(THF)3], (7Li, 29Si).

Li-1H HOESY has been used to characterize two chiral amides prepared from (R)-(Me2NCH2CH2) (l-Ph-2-pyrrolidin-l-yl-ethyl)amine and (R)-(MeOCH2 CH2)(-l-Ph-2-pyrrolidin-l-yl-ethyl)amine. Diffusion of [LiN-(O2SCF3)2] in a PVDF-type gel polymer has been investigated using NMR spectroscopy. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

The solvation of Li+ in LiPF6 dissolved in propylene carbonate solutions has been studied using the NMR field gradient technique. Self diffusion of lithium electrolytes in propylene carbonate, and copolymers of maleic anhydride and tetraethylene glycol divinyl ether has been investigated. 6Li, 7Li and 31P NMR spectroscopy has been used to study Li+/Mg2+ competition for red blood cell membrane phospholipids. NMR data have also been reported for α-lithioisobutyrate, (6Li), [LiOCHPh2], (7Li), [Li{Al-(OCH2Ph) 4}], (27A1), and [Li2, {(R)-binol}] (7Li).

The optical ac Stark effect in 23Na NMR spectra has been studied. The electric quadrupole moments of 26Na, 27Na, 28Na and 29Na have been measured by (β-NMR spectroscopy in single crystals of NaNO3. Relative ionophoric activities have been probed using 23Na NMR spectroscopy. Intra- and extra-cellular Na+ have been quantified using 23Na NMR spectroscopy. 1H, 13C and 23Na NMR spectroscopy has been used to study sodium polyacrylate water uptake. Na+ co-transport in human breast cancer cells has been studied by 23Na and 31P NMR spectroscopy. 1H and 23Na NMR spectroscopy has been used to study the thermal stability of the double helix structure of an 11-basepair oligonucleotide. The blocking of Na+-H+exchange by cariporide in ischemia has been studied using 23Na and 31P NMR spectroscopy. Na+ has been quantified in intact bovine articular cartilage using 23Na MRI. 1H and 23Na NMR micro-imaging of intact plants has been reported. The halotolerant bacterium Holomonas israelensis has been studied by 23Na, 31P and 133Cs NMR spectroscopy. The state of NaCl in snow crab meat has been examined by 23Na and 35C1 NMR spectroscopy. The 133Cs NMR spectra of the fruiting bodies of Pleurotus ostreatus show two NMR signals. J (133Cs19F) is observed at low temperature in the 19F NMR spectrum of the Cs+ complex of the adamantane analogue, N4(CH2C6H3-2-F-3-CH2)6. NMR data have also been reported for [Li(DME)] +, (7Li), (12), (23Na), sodium poly(α,L-glutamate), (23Na), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

1H and 13C NMR investigations of [Ca{C(SiMe3)2Ph}2] indicate that the presence of the silyl group localizes the charge on the phenyl group. The 1H and 13C NMR spectra of [(η5-C5Me5)2Be] show one signal down to -90°C. 25Mg NMR spectroscopy has been used to study the binding of Mg2+ to ATP, and PvuII endonuclease. NMR studies of calcium-induced alginate gelation have been reported. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

2.2 Complexes of Group 3, the Lanthanides and Actinides. – Strong diagostic bonding has been observed between the SiH and the metal centres in [M{N)SiHMe2)}3(THF)n], M = Sc, Y, La, by 1H, 13C, 29Si and 89Y NMR spectroscopy. The 31P NMR spectrum of (13), M = Yb(OEt2), shows coupling to two inequivalent 171Yb nuclei. The Yb3+ complex of (+)-(18-crown-6)-2,3,ll,12-tetracarboxylic acid has been shown to be a chiral discrimination reagent. 1H NMR shieldings have been calculated for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

2.3 Complexes of Group 4. – 13C and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] measurements suggest that Zr(<ansa-fluorenyl) complexes have η1- and η3-bonding. 47Ti and 49Ti NMR chemical shifts, linewidths and T1 measurements on [Ti(OR)4] and [TiX4] have been reported. 1H NMR spectroscopy has been used to characterize the catalytic system [Ti(OPri)4]/D-mannitol. Some titanium oxo-polymers have been characterized by 17O NMR spectroscopy. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] dendrimers with [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] terminating groups, [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

2.4 Complexes of Group 5. – 1H NMR relaxation measurements have been applied to [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] to determine the Nb-H distance as 1.781 Å. NOESY has been applied to determine the structure of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]. The origin of the asymmetry in the 1H and 13C NMR spectra of chlorodicyclopentadienyloxoniobium(V) complexes has been re-examined. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

51V NMR spectroscopy has been used to demonstrate the presence of peroxo complexes when sulfide to sulfoxide oxidation is catalysed by VIV Schiff base complexes. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (17), (51V), bioactive peroxovanadium bipyridyl complexes, (51V), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

51V NMR chemical shifts have been computed for vanadate-glycylserine isomers. Peroxovanadium complexes have been speciated using 51V NMR spectroscopy. The coordination of [VO5]-] to histidine has been investigated by 51V NMR spectroscopy. 51V NMR spectroscopy has been used to investigate the interactions of vanadate oligomers with myosin. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], a new mannopyranoside vanadate, [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

2.5 Complexes of Group 6. – The 1H NMR spectrum of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] has prochiral CH2 protons with a remarkable chemical shift separation at δ 11.4 an 3.15. Coordination of (18) to Cr(CO)3 produces a large low frequency shift of the 31P signal. Ring currents in [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] have been examined. The 13CO NMR spectrum of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], is a singlet. [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] acts as a chiral shift reagent for chiral Cr(CO)3 complexes. The conformational features of (19) have been determined using two-dimensional NMR spectroscopy. The 19F and 31P NMR spectra of [Mo(CO)3 (PF3)3] have been completely analysed. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

The site of attachment of CrIII to [2Fe-2S] ferredoxins has been investigated using NOESY. The NMR chemical shifts of molybdenum oxide species have been calculated. Peroxo complexes of sugar acids with oxoions of MoVI and WVI have been studied by 17O, 95Mo and 183W. The interactions between solvent molecules and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] have been investigated by 95Mo NMR spectroscopy. The measurement of relative integrated intensities and peak heights of 183W NMR spectra of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] and [FORMULA NOT REPRODUCIBLE IN ASCII] have permitted assignments. The shielding of 183W in [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] has been calculated. The complexes, [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], have been characterized by 19F NMR spectroscopy. NMR data have also been reported for [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] complexes of meso-2,3-dimercaptosuccinic acid, [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].

2.6 Complexes of Group 7. – 1J (2H 1H) is 34.5 Hz in [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]. The 1C chemical shifts of the alkyne carbon atoms move to a limit of 64 to 67 ppm in [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII]. The conformations of glycosyl and mannosyl manganese pentacarbonyl complexes have been investigated by 1H, 13C and 55Mn NMR spectroscopy. The [AB]231P{1H} NMR spectra of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] have been analysed. NMR data have also been reported for (22), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII].