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 1H, 2H, 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.

Several relevant reviews have been published, including 'Para-hydrogen-induced polarization and polarization transfer in hydrogenation and oxidative addition reactions. A mechanistic approach', 'Application of NMR techniques to organometallic compounds', 'Shift-reagent-aided 23Na NMR spectroscopy in cellular, tissue, and whole-organ systems', 'The Cinderella Nuclei', which contains 57Fe, 89Y, 103Rh, 107Ag, 109Ag, 183W, and 187Os NMR data, 'Electronic mechanisms of metal NMR chemical shifts in transition metal complexes', 'New possibilities of NMR in mechanistic studies of homogeneous and heterogeneous catalysis', which contains 13C, 17O, 51V, 59Co, and 95Mo NMR data, 'Inorganic xanthates: a structural perspective', and 'Advances in phosphorus-31 NMR'.

A number of papers have been published which are too broadly based to fit into a later section and are included here. Mass effects in the theoretical determination of nuclear spin relaxation rates for atomic hydrogen and deuterium have been examined. Nuclear shielding constants and shielding polarizabilities have been calculated for H2, N2, HF, and CO. Nuclear spin longitudinal relaxation times of deuterium gas have been interpreted in terms of relaxation of the ortho species. Ab initio calculations have been performed for 7Li in LiH, 21Ne in NeH, 23Na in NaH, and 39Ar in ArNe and Ar···NaH, as a function of internuclear separations. Nuclear singlet-triplet mixing has been analysed to understand NMR studies of homogeneous catalysis using para-hydrogen. Nuclear spin relaxation of the dihydrogen ligand in nonclassical transition metal complexes has been explained. Deuterium quadrupole coupling constants and ionic bond character in transition metal hydride complexes have been determined from 2H NMR T1 relaxation data in solution. A multiband tight binding model of the metal trihydrides, including on-site repulsion and exchange, has been examined. The nature of the high-temperature broadening of magnetic resonance lines of solvated complexes has been examined.

Trends in the 1H and 13C NMR spectra of heterobinuclear and heterotrinuclear transition-metal μ-allenyl complexes have been examined. 13C NMR spectra of ring-substituted η5-cyclopentadienyl metal complexes have been obtained using INEPT and nJ(13C1H), n = 2, 3, observed. Theoretical studies of xanthates, dixanthogen, metal xanthates, and related compounds have been used to interpret 13C NMR data. A 13C NMR study of boron, silicon, tin, phosphorus and tellurium fluorides has been reported. Empirical equations of 13C chemical shifts of the phenyl ring were deduced. NMR data have also been reported for barium, strontium, lead and zinc salts of sulfanilic acid, (13C), NiII, ZnII, CdII, and HgII complexes of poly(cinnamaldehyde-anthranilic acid), (13C), metal complexes of 4-xylosylamino-5-nitroso-6-oxopyrimidine derivatives, (13C, NiII, ZnII, CdII, and HgII complexes of pyrazine-2-carboxylic acid hydrazide and salicylidene-2-pyrazinoylhydrazine, (13C), NiII, ZnII, CdII, and HgII complexes of Z-2-benzylthio-4-hydroximinomethyl-l-p-methoxyphenyl imidazole, (13C), LiI, CuI, AgI, and CdII complexes of [C6H4(OSiMe2NBut)2]2-, (13C, 29Si), 1, (M = CaII, LaIII, ThIV, UVI, PbII; 13C), and complexes of HgCl2, CdCl2, and SbCl3 with EtNH2, Et2NH, and BuNH2, (13C).

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.

Complexes of Groups 1 and 2. — Reviews have appeared entitled 'Recent results in NMR spectroscopy of organolithium compounds', 'Solution structures of lithium dialkylamides and related N-lithiated species: results from 6Li-15N double labelling experiments'. and 'Intracellular concentrations of lithium as studied by nuclear magnetic resonance spectroscopy'.

Polarization-dependent frequency shifts from rubidium-helium-3 collisions have been investigated using 3He NMR spectroscopy. 1H and 13C NMR spectroscopy has been used to study substituted pyridine-butyllithium adducts. 6Li and 13C NMR spectroscopy has been used to characterise ButLi/LiOBut mixed aggregates. 13C experimental and IGLO-calculated chemical shifts of LiCCl3 and Bun3SnR have been reported. 1J(13C13BC) =35.9 Hz and 2J(13C1H) have been determined for (C2H3)Li. (C2H3)6Li has been examined at -90 °C to give a comprehensive determination of coupling constants, including 1J(13C6Li). Sizeable J(6Li1H) values have been observed for [2-LiC6H4CH=CHLi]2 and the two inequivalent lithium resonances were assigned. 1J(13C13C) has been measured for PhLi and PhMgBr as 29.5 and 36.1 Hz respectively. The 133Cs- 1H HOESY NMR spectrum of [Ph3CCs-PMDTA]n shows agostic interactions between caesium and hydrogens. NMR data have also been reported for [MeLi.THF]4, (7Li, 13C), α,ω-Li2 polyisoprenes, (7Li), OCMe2CMe2OBCH2Li, (11B), 2, (13C) [Ph2C(C5H4N)M], {M = Li(OEt2)2, Na(THF)3, K(PMDTA); 13C, 3, (6Li), 13C [(Me3Si)3CLi(THF)2], (7Li, 13C, 29Si, including CPMAS) 4, (7Li, 13C), 5, (13C), 6 (13C), [Li(2,4,6-Pri3 C6H2)]4, (7Li, 13C), [M[phenyl bicyclo-[3.2.1]oct-3-en-2-yl)], (M = Li, K; 7Li, 13C), [(R2CO)Li{C5(SiMe2H)5}], (7Li, 13C, 29Si), [{1,4-(Me3Si)2C8H6}{Li(TMEDA)}2], (7Li, 13C), [Li2(TMEDA)2 (η5:η5-C24H14)], (13C), [K(TMEDA)2(C13H9)], (13C), [Rb(PMDTA)(C13H9)], (13C), [{(Me2N)3Si}NLiSiMe3], (13C), [(Me3Si)3SiLi(THF)3], [(Me3Si)3SiSi(SiMe3)3], (7Li, 13C, 29Si), [Cu2...