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, 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.

Several reviews have been published which are relevant to this review: 'Understanding NMR chemical shifts', 'Two-dimensional correlation spectroscopy by scalar couplings: A walk through the Periodic Table', 'In vivo31P and 23Na NMR spectroscopy and imaging', 'Application to the calcium-binding regulatory enzyme, calmodulin. A quantitative study on metalloenzymes', which contains 43Ca and 113Cd NMR spectroscopy, 'The correlation between transition metal NMR chemical shifts and the stability of coordination compounds', 'Transition metal complexes containing hydrazine and substituted hydrazines', which contains 15N and 103Rh NMR spectra, 'Coordination chemistry of metallodrugs: insights into biological speciation from NMR spectroscopy', which contains 15N, 109Ag, and 195Pt NMR spectra, '1H-31P pulsed field gradient heteronuclear multiple-bond correlation (PFG-HMBC) spectroscopy', which contains spectra of compounds such as [(η5-C5H5)Ni(µ-H)(µ-CO) -W(η5-C5H5)2], 'An assessment of the parameters relevant to the subdivision of σ and π electronic effects in M–P bonds', which contains δ(13CO) and 1J(M–P), NMR in the study of inorganic complexes of the noble metals', 'Metallothio-neins', which contains 113Cd NMR spectra, 'The chemistry of metal complexes with selenolate and tellurolate ligands', which contains 77Se and 125Te NMR spectra, 'NMR spectroscopy (of halides and pseudo-halides)', 'Mesoionic compounds - structure and NMR spectral parameters', which contains 14N, 15N, 17O, and 77Se NMR spectra, 'Molecular architecture of bimetallic active centres and their bifunctional catalysis', which contains 129Xe NMR spectra, 'Preparation of samples for analysis of wastewaters by NMR spectroscopy', 'Applications of nuclear magnetic resonance in the study of magnetic materials', and 'Application of NMR methods to catalysis'.

A number of papers have been published which are too broadly based to fit into a later section and are included here. A three-pulse sequence has been described which generates detectable three quantum coherence in I = 3/2 and 3 and five quantum coherence in I = 5/2 spin systems. The variation of the NMR shielding with the Periodic Table has been examined. The spin-lattice relaxation times of 1H2 and 2H 2 have been determined in aqueous solutions. The theory of thermal effects in the nuclear magnetic resonance spectra of metal hydrides undergoing quantum mechanical exchange has been developed. A theoretical study of the origin of 1H chemical shifts in low-valent transition metal hydrides has been reported. A theoretical study of 13C and 17O NMR shielding tensors in transition metal carbonyls based on density functional theory and gauge-including atomic orbitals has been carried out. High-pressure NMR spectroscopy has been used to study metal complexes in supercritical fluids. The molecular dynamics in [M(OMe)6], M = U, Mo, W, Sb, have been analysed using 1H T1 measurements. The O NMR chemical shifts of several previously characterized mono- and diperoxo complexes of vanadium (V), molybdenum (VI), tungsten(VI) and titanium (IV) have been measured. Monoperoxo complexes exhibit 17O chemical shifts of δ 500–660, while those of diperoxo complexes fall in the range δ 350–460. The lineshapes in solution of an I = 1/2 nucleus with scalar coupling to one quadrupolar nucleus which is subject to random-field relaxation have been calculated using a relaxation matrix treatment and applied to 59C coupled to Co. The analysis of the signal to noise ratios for noise excitation of quadrupolar nuclear spins, e.g., Cl, has been performed in zero field. The shift of the NMR frequency under sample spinning has been examined and applied to 1H and 119Sn in liquid samples.

2 Stereochemistry

Complexes of Groups 1 and 2. – Four reviews have appeared entitled 'In vivo MRS measurement of lithium levels in brain', which includes Li NMR spectra,'Use of 23Na NMR to study sodium-macromolecule interactions', 'Nuclear magnetic resonance analyses of Grignard reagents', and 'Physical methods for studying the biological chemistry of magnesium', which contains 25Mg NMR spectroscopy.

Pulsed field gradient 'inverse' HOESY has been applied to the isotope pair 1H, 7Li in Bun Li. IGAIM 13C and 1H chemical shifts have been calculated for organolithium compounds. The formation of [Li2((Me3Si)PhCC-(SiMe3) C(SiMe3)CPh(SiMe3)}] has been demonstrated using 1J(13C6Li) = 2.7 Hz, and by using two-dimensional 6Li-29Si HMQC which detected 2J (29Si6Li) and 3J(29Si6Li). 1J(13C6Li) = 17.6 Hz has been observed in Li enriched [LiC=C(SiMe3)CMe2]. The nature of the lithium counter cations in lithiated (E)-1-(RS)-but-2-ene has been investigated by 6Li-1H HOESY NMR spectroscopy. 1H-7Li HOESY NMR spectroscopy has been used to show short contacts between the peri hydrogen and lithium in [(ArOLi)m(BuLi)n]. NMR data have also been reported for [(2-Ethexyl)M], (M = Li, Na; 7Li, 23Na), [But2SiFCLi(GeMe3)2·THF], (7Li, 29Si),[LiOCBut2C=C(Li) CMe2], (7Li), [(η3-ButMe2 SiCHCHCHSiButMe)Li(tmeda)], (7Li, 29Si), [Li{η5-C5(CH2Ph)5}][Al {η5-C5(CH2Ph)5}2], (7Li, 27Al), (1), (7Li), [(µ-Li)3{µ-C6H3-2,6-(NMe2) 2}3], (6Li), [LiC6H3 -2,6-(C6H3Pri2-2,6)2], (7Li), [Cs2(Me2SiNHMe2SiN) 2·3(THF)], (29Si, 133Cs), [Ar2HGeLi], (7Li), and [Me3Si)3GeLi(THF)3], (7Li).

Ab initio molecular orbital calculations of 1J(15N 6Li) have been carried out for lithium amide monomers and oligomers, and mixed aggregates with LiCL. There is a linear correlation between δ (7Li) and the lithium coordination number in lithiated phenylhydrazides. The 29Si NMR spectra were also recorded. Two-dimensional 1H6Li HOESY has been used to determine close lithium-hydrogen contacts in [(R1R2N)(R3N)C=C(NR3) (NR1R2)]Li2. The 7Li NMR signal of the lithium salt of 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis (N-methylpyridi-nium-4yl)porphyrin is at δ -10.25. NMR data have also been reported for [Li(Me2NBH3)], (7Li, 11B), [(C6F5)NHLi·2THF], (7Li), [Li{NHCMe=CH (CN)}(NC5H5)]2, (6Li, 7Li CP MAS), β-lithiated amides, (6Li), [{Li(THF)2} {C20H12(NSiMe3)2}], (7Li, 29Si), [{N(CH2CH2SiMe3)3} Y(µ5-O)Li3(µ2-OCHCH2)Y(THF) {N(CH2CH2SiMe3)2CH2CH 2N(SiMe3)(CHCH2)}], (7Li), [{HC (SiMe2N{(S)-CHMePh})3}SnLi], (7Li, 29Si), [Li{Eu(phthalocyaninato)(tetra-4-pyridylporphyrinato)}], (7Li), syn-[Li2(THF)2{PhP(CH2SiMe2 NSiMe2CH2)2PPh}], (7Li), and [(2,4,6-Pri3C6H2SiPri2P)Li2(FSiPri2C6H2 Pri3-2,4,6)], (7Li).

1J(31P7Li) has been calculated in [LiPH2] and [LiPMe2] monomers and oligomers using ab initio molecular orbital calculations. The lithium derivatives of R(2,4,6-But3 C6H2)PH are monomeric in solution as indicated by the 1:1:1:1 quartet of 1J(31P7Li) coupling in the 31P NMR spectrum at low temperature. The 31P NMR spectrum of [MeC{P(C6H2But3-2,4,6)2} Li(THF)2] shows 1J(31P7Li) = 41 Hz. NMR data have also been reported for [Li(THF)2{η2 -(ButP)2P}], (7Li), [MP(CH6H4 OMe-2)], (M = Li, Na; 7Li, 23Na), [Li2{PhP (C6H3-2-S-3-SiMe3)}(dme)]2, [Sn{PhP(C6H3-2-S-3-SiMe3)}], (7Li, 119Sn), and [Li2{P(SiPh3)2)2], (7Li).

The spin-lattice relaxation rates of 7Li, 23Na, 27Al, 71Ga, and La nuclei in electrolyte solutions have been investigated as functions of the isotopic composition of the solvent. The data were compared to the results for the 2H, 14N, and 17O nuclei of the solvent and nitrate anion. The 7Li quadrupole splitting constants for dimeric lithium phenolates have been determined from measurements of 7Li and 13C spin lattice relaxation times. A quantum-chemical study of the structure, aggregation, and 13C NMR shifts of the lithium ester enolate on methyl isobutyrate has been reported. 1H, 6Li, and 13C NMR spectroscopy has been used to show that But2-Li2,4,4-trimethylglutarate forms well-defined aggregates with LiOBUt. The dipolar interaction of quadrupolar nuclei in solution has been measured for [Li(kryptofix 21l)]+ using multiple quantum 7Li NMR spectroscopy. 7Li NMR spectroscopy has been used to study Li+ transport into SH-SY5Y human neuroblastoma cells. The uptake of Li+ into human 1321 N1 astrocytomas has been investigated using 7Li NMR spectroscopy. NMR data have also been reported for [CH2(CH2CH2)2P (CHPh)OLi], (6Li, 7Li), [Li{(Me3Si)3C} Al(OBut)3], (7Li, 27Al, 29Si), [{Li(OCButAsCButO)-(OEt2)}2], (7Li), [LiAl{OCPh(CF3)2}4], (7Li), [Li(THF)2(OEt2)2] [(OC)4Cr(P-BUt2)PCr(CO)5], (7Li), (2), (7Li), [LiL(O3SCF3)], {L = (3); 7Li}, [Li{SC6H3-2,6-(C6 H2Me3-2,4,6)2}]3, (7Li), and [Li2Se(NBut)3]2, (7Li, 77Se).

The use of B1 selective pulses has been applied to the use of 23Na in imaging. The 23Na NMR spectrum of molten NaNO3 has been recorded. A novel liquid crystalline phase has been identified in the κ-Carrageenan/NaI/water system using 23Na NMR spectroscopy. Na NMR relaxation in systems of latex and ionic surfactant has been investigated. The effects of thickening agents on sodium binding and other taste qualities of soup systems have been studied using 23Na NMR spectroscopy. 23Na NMR spectroscopy has been used to map sodium ion concentration in normal rat brain. The ion activity coefficients and fixed charge density in cartilage have been determined using 23Na magnetic resonance microscopy. The effect of gossypol on cultured TM3 Leydig and TM4 Seroli cells has been studied using 23Na NMR spectroscopy. A 23Na multiple-quantum-filtered NMR study of the effect of the cytoskeleton conformation on the anisotropic motion of Na+ in red blood cells has been reported. 133Cs NMR spectroscopy has been used to probe intracellular space in vivo.

A very large 1J(31P31P) = 95 Hz has been observed in (4). The 29Si and 119Sn NMR spectra were reported. NMR data have also been reported for [Mg{C(SiMe3)2 (SiMe2OMe)}2], (29Si), [Cy7 Si7O12MgTiCl3]n, (n = 1, 2; 29Si), and [Sr(OSiPh3)2(15-crown-S)(THF)], (29Si).

Complexes of Group 3 and the Lanthanides. – 13C NMR spectroscopy has been used to study the structure of isolated Sc2 C84. 139La NMR chemical shifts have been measured for several anionic complexes such as [La(η3-C3 H5)4]. The 15N 89Y and chemical shifts and 1J(89Y15N) in aqueous solutions of three yttrium complexes of polyaminocarboxylic acids have been reported. The coordination structures of lanthanide(III) and uranyl(VI) nitrato complexes with N,N'-dimethyl-N,N'dibutylmalonamide have been investigated using 1H, 13C, and 14N NMR spectroscopy. The 89Y NMR spectrum of [ClY(OC6H4CH2 NMe2-2)3Y(OC6H4CH2 NMe2-2)3Na] shows two 89Y NMR signals with J(89Y89Y) = 0.4 Hz. NMR data have also been reported for [YR2(3,5-Me2pz)3BH], (89Y), [(η5-C5Me5)2LnSiH (SiMe3)2], (29Si), [Yb{C(SiMe3)2(SiMe2X)}2], (29Si, 171Yb), [Yb(η5-C5 Me5){Si(SiMe3)3}(THF)2], (29Si, 171Yb), [Yb6(η5 -C5Me4SiMe2But)6 I8)2-, (7Li, 29Si), [{PhC(NSiMe3)2}2YCl-THF], (89Y), [(DMF)10Yb2{Pt(CN)4}3]∞ (195Pt), [Sm{(µ-PBut2)Li(THF)}2], (7Li), (5) (29Si), [Y{2,6-diacetylpyridinedi(acetic hydrazone)}(OH2)6]3+, (89Y), [La (NC5H3-2,6-(CO2)2}3] 3-, (14N), and [{YbI(µ-OCPh3) (η2-DME)}2], (171Yb).

Complexes of Group 4. – The metal-arene affinities have been investigated in [(η5-C5Me5)MMe2 (η6-arene)]+, M = Ti, Zr, Hf. The origin of the unusual large carbonyl 13C shifts and the unusual Periodic trends in four-legged piano-stool complexes [(η5-C5H5) M(CO)4]-, M = Ti, Zr, Hf, and in related species have been investigated by using a combination of ab initio effective-core potentials and density-functional theory. The 13C NMR spectra of mono- and disubstituted dicyclopentadienyl pseudohalogen or dicarbonyl titanium complexes have been analysed. 1J(13C13C) has been determined in [Zr3(η5-C5Me5) 2 (µ-13C13CO)(µ3-O) (O213CNPri2)6] as 78.9 Hz. Zr NMR chemical shifts and line widths have been reported for a number of ring-bridged and ring-substituted zirconocene dichloride, dibromide, and dimethyl complexes, and fitted using ab initio computations at the SCF level. By using 17O and 1H NMR spectroscopy, peroxotitanium species formed in the reaction of [TiO(acac)2] and Ti(OEt)4] with H2O2 have been characterized. NMR data have also been reported for [[(η5-C5 H5)2Zr(µ-H)(SiHR)]22+, (11B, 29Si), [[(η5-C5H5) 2Zr(BH4)(OTf)], (11B), (6), (11B), [{PhC(NSiMe3)}2MMeCl], (M = Ti, Zr; 29Si), [(Me3M1CH2)3 M2Si (SiMe3)3], (M1 = C, Si; M2 = Ti, Zr; 29Si), [(2,4,6-Me3C6H2)2 BNCH2CH2NB(C6H2Me3-2,4,6) 2TiCl(R)], (11B), (7), (11B), (8), (11B), (9), (11B, 29Si), [MeC(CH2NSiMe3) 3TiM(CO)2(η5-C5H5)], (M = Fe, Ru; 29Si),(10), (29Si), [Zr(CO)5 (SnMe3)2]2-, (119Sn), [{(N-Pri-2-PriN-troponimine)Sn} {(η5-C5H5)ZrCl2(µ-Cl)3 ZrCl2(η5-C5H5)}], (119Sn), [(η5-C5H5-n)Men)2Ti {η2-C2(SiMe3)2}], (29Si), [(η5-C5H4-ansa-η5 -C5H4)Ti{<η2-C2(SiMe3) 2}], (29Si), [(η5-C5H4 SiMe3)TiF(NSnMe3)2], (119Sn), [(η5-C5Me5)2TiTeSnPh3], (119Sn), [(η5-C5H4SiMe2 SiMe2C5H4-η5)MCl2], (M = Ti, Zr, Hf; 29Si), [(η5-C5H4 CH2CH2NPri2)(η5C5 H4SiMe3)TiCl2], (29Si), [{TiCl3(η5-C5H4)}BPh], (11B), [{Me2Sn(η5-C5H4)} Zr(NMe2)2], (1119Sn), [(η5 -C5Me5)Ti(η2-SeTe)], (77Se, Te), [(PhB(η5-C5H4)}ZrCl2], (11B), [(η5-C5H4SiMe2SiMe2 C5H4-η5)ZrCl2], (29Si),[R2Si(η5-fluorenyl)(η5 -C5H4)ZrCl2], (29Si), [MeSi(SiMe2NR)3MCl], (M = Ti, Zr; 29Si), [{MeC(CH2NSiMe3)3Ti}2(µ-O)], (29Si), (11), (29Si), [R1N-(SiMe3) SiO3Ti(OR2)]4, (29Si), [{Cd(OPri)3}Ba{M2(OPri)9}] 2, (M = Ti, Hf; 113Cd), [MZr(OR)6], (M = Sn, Pb; 119Sn, 207Pb), 8-membered Zr and B cyclosiloxane compounds, (11B, 29Si), and [M{ESi(SiMe3)3}4], (M = Ti, Zr, Hf; E = Se, Te; 77Se, 125Te).