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.

A number of reviews have also been published: 'The DFT route to NMR chemical shifts', 'Correlations between transition-metal NMR chemical shifts and reactivities', which contains 51V NMR data, 'Probing organometallic structure and reactivity by transition metal NMR spectroscopy', which contains 51V, 53Cr, 55Mn, 57Fe, 59CO, 91Zr, 103Rh, and 187Os NMR data 'NMR spin-lattice relaxation approaches to characterization of transition metal hydride complexes in solution', 'Applications of heteronuclear X,Y-correlation spectroscopy in organometallic and organoelement chemistry', 'Direct determination of quadrupolar and dipolar NMR correlation times from spin-lattice and spin-spin relaxation rates', 'Reducing the NMR line widths of quadrupolar nuclei by employing supercriticial solvents', 'Comparative solid state and solution NMR structural and dynamic studies on tetra-and higher-nuclearity transition metal carbonyl clusters', 'NMR studies of molecular recognition by metalloporphyrins', 'Quadrupolar metal ion NMR studies of metalloproteins', which contains 27Al, 43Ca, 45Sc, 51V, 69Ga, and 71Ga NMR data, 'NMR spectroscopic studies of I = 1/2 metal ions in biological systems', which contains 109Ag, 111Cd, 113Cd, and 199Hg NMR data, 'Electronic state of ultrafine particles suspended in liquid media', and 'The characterisation and use of polycation-exchanged bentonites'.

A number of papers have been published which are too broadly based to fit into a later section and are included here. Complexes of the C(SiMe3) 2-SiMe2NMe2 with lithium, aluminium, mercury and tin have been investigated by 7Li, 15N, 27Al, 29Si, 119Sn, and 199Hg NMR spectroscopy. The 17O NMR tensors, electric field gradients and chemical shifts have been modelled in oxides and polyoxometallates. Density functional calculations of NMR chemical shifts have been applied to 183W and 207Pb chemical shifts in a wide range of compounds. A DFT-based study of 1K(M-X) has been reported for transition metal carbonyl, oxo, fluoro, and phosphine complexes. Line narrowing of I = 1/2 spins coupled to quadrupolar nuclei in liquids in the presence of weak decoupling fields has been examined and applied to 10B-enriched sodium borocaptate.

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 'Cryptand ligands for selective lithium coordination', which contains 7Li NMR data, and 31P NMR spectroscopy of the mouse heart', which contains 23Na NMR data, have appeared.

1J(13C6Li) has been observed in [Prn8(PrnO)4Li12]. The structure of Z-[(2,4, 6-But3C6 H2P=C)ClLi(sol)n,] has been determined using two-dimensional 31P, 6Li HMQC. 6Li and 15N NMR spectroscopy has been used to study [Et2NLi] solvated by oxetane, THF, and Et2O. NMR data have also been reported for [Li{CH(SiMe3)PPh2=NSiMe3} (OEt2)2], (7Li), lithiated allylic norbornenyl carbanions, (6Li), [ButSi(OSiMe2 NLiBut)3], [But(OSiMe2NH -SiMe3)3], (7Li, 15N, 29Si), [Ph2PNLiBut]2, (7Li), [MC(SiMe3)(SiMe2X)2], (M = Li, K; 7Li, 15N, 29Si), [LiC(SiMe2H) 3]·2THF, (7Li, 29Si), [ButO2 CCMe-LiCH2CMe2CO2But], (7Li), lithiated phosphoric triamides, (7Li), [Li{η3-CH-(CHSiMe2But)(CHSiMe2R)} (TMEDA)], (7Li, 29Si), [(HMe2Si)2 C=C(SiHMe2)2]-[MLn], (M = Li, Na, K, Rb, Cs; 6Li, 29Si), [Li{η3-PhCHCHCHCH(Boc) -C6H4-4-OMe}], (6Li), [Li2Ge C4Et4], (7Li), [Li3{1,2-(2,4,6 -C6H2)2-1,2-B2-3,5-Me2 -4-CH(SiMe3)2-C3}], (7Li, 11B), [Li2((C5Me4)SiMe2PCy}], (7Li), [Li(THF)4][2,6-(2,4,6-Me3C6H2)2 C6H3Cu2I2], (7Li) [Pri3SiSiLi2SiPri3], (6Li, 29Si), [Li(THF)3Sn(SiMe3) 3], (7Li, 29Si, 119Sn), (1), (7Li, 14N), side arm effects on cyclen-alkali metal cation complexation, (7Li, 23Na), (2), (7Li, 29Si), [LiNMe(CH2)2NMe2], (7Li), [(Me2NCH2CH2NMe)Li(THF)2], (6Li), [{Me2NCH2CMe2CH2N(H)Li}6], (6Li), [Li3{RNC(H)NC(H)NR)3], (7Li), [Pb(η5-P3C2But2) (μ-Cl)2Li(tmen)2], (7Li, 207Pb), [Li{N(SiMe2R1)-CBut(CH3)SiMe2 R2}(TMEDA)], (7Li, 29Si), (3), (7Li), Li+ complexes of (4), (7Li), [Li(R1 NSCR2)]n, (7Li), [(Pri3 SIP)10Li16], (7Li, 29Si), [LiPHB-(NPri2){N(SiMe3)2}], (7Li, 11B), and [Li(M[Te(NBUt)3] 2}], (M = Sb, Bi; 7Li, 125Te).

1H and 7Li magnetic relaxation dispersion data have been presented for the field dependence of T1 of [Me4N]+ and [Li(OH2)n]+ in GdIII and MnII solutions. 7Li double quantum filtered NMR spectra have been used to investigate ordering processes of synthetic Li+-saponites dispersed in water. The conformational behaviour of aqueous micelles of Na N-dodecanoyl-L-prolinate has been studied using 1H, 13C and 23Na NMR spectroscopy. Colloidal dispersions of sodium and potassium phosphates have been studied using 31P NMR spectroscopy. 87Rb NMR spectroscopy has been used to study molten and glassy 2Ca(NO3)2·3RbNO3. The 133Cs NMR spectrum of [NEt4][CS((η5 -C5Me5)Rh(CN)3}4{Mo(CO)3} 4] shows two signals due to free and bound Cs+ when Cs+ is added. 133Cs NMR spectroscopy has been used to investigate anisotropic block copolymers. The formation of micelles and aggregates in D2O solutions of [CnF2n+1 CO2Cs] has been studied using 19F and 133Cs NMR spectroscopy. NMR data have also been reported for [(Cy7 -Si7O12){Cy7Si7O11, (OSiMe3)}YLi2(THF)2(MeCN)], (29Si), [Li4(THF)4][(5)], (6Li, 29Si), [Li4(THF)4Mg{O2S(NBut)2} 3]2, (7Li), and [Li(diglyme)2][ (1,4-R2C8H6)2Sm2 (μ-Cl)3], (29Si).

7Li and 19F NMR spectroscopy has been used to study drugs in the brain. 7Li, 23Na, 87Rb and 31P NMR spectroscopy has been used to study cation fluxes in isolated rat hearts. A 7Li and 23Na relaxation study of Li+ and Na+ in human blood cell membrane has been reported. The pH regulation of K+ efflux from myocytes in isolated rat hearts has been studied using 7Li, 31P, and 87Rb NMR spectroscopy. The micellar properties of sodium cyclohexylalk-anoates have been investigated in aqueous solution using 13C and 23Na NMR spectroscopy. Experiments that selectively excite I = 3/2 nuclei exhibiting residual quadrupolar splittings have been used to acquire 23Na NMR spectra from a range of biologically relevant samples containing sodium in ordered environments. 23Na NMR images have been used to allow distinction of scar and intact tissue due to differences in intensity of the sodium signal. Levels of intracellular sodium, intracellular calcium, intracellular pH and high energy phosphates have been investigated using 19F, 23Na, and 31P NMR spectroscopy. Ion homeostasis has been investigated using 23Na NMR spectroscopy. Changes of intracellular 23Na T2 during ischemia and reperfusion in isolated rat hearts have been studied. 23Na NMR shift reagents have been used to enhance the cardiac staircase effect in isolated perfused rat hearts. 23Na NMR spectroscopy has been applied to isolated perfused guinea pig hearts. 23Na NMR spectroscopy has been used to evaluate articular cartilage degradation. Potassium fluxes in whole rat hearts have been measured using 87Rb NMR spectroscopy.

25Mg NMR spectroscopy has been used to study the solution behaviour of magnesium tetrahydridoborates. 15N and 43Ca NMR spectroscopy has been used to study Mg–Ca interference in calmodulin. The measurement of one bond dipolar couplings, 1J(15N 1H), through lanthanide-induced orientation of a calcium binding protein has been reported. NMR data have also been reported for [(η5-C5Me5)BeAsBut2], (9Be), Mg and Zn porphyrins, (15N) ([(Me3Si) 2NCa(μ-PHSiPri3)Ca(tetrhydropyran)3], (29Si), [(THF)4Mg6-(PSiPri3) 6], (29Si), [M {PCPh=C(SiMe3)C(SiMe3 =CPh}(THF)4], (M = Ca, Ba; 29Si),[Be(malonate)2] 2-, (9Be),' and [BaB2(OPh)8(THF) 4], (11B).

2.2 Complexes of Group 3, the Lanthanides and Actinides – Scandium-crown ether complexes have been studied by 45Sc NMR spectroscopy. Lanthanum binding to aqualysin has been probed by 139La NMR spectroscopy. Relativistic density functional calculations of 235U chemical shifts in diamagnetic uranium compounds have been reported. 17O NMR spectra of [UO2]2+ have been studied while the ion was irradiated by laser and changes attributed to paramagnetic interactions. NMR data have also been reported for [ScCl-(C5H5BMe)2]2, (11B) [ScCl2{N(SiMe3)2}(THF)2], (29Si)," [{(4-MeC5H3N-2-NH)-Me2Si} 2OY(BH4)Cl(THF)]+, (29Si), [(η5-C5H5)2Y{η3-N (EPPh2)2}], (E = S, Se; 77Se, 89Y), (6), (29Si), [(η5-C5H5)3 La(OSR1R2)], (139La), [HB(3-But -5-Mepz)3Yb(μ-H)]2, (11B, 171Yb), [Cl3SnC(SiMe3)2SiMe2CH2 CH2SiMe2C-(SiMe3)2SnCl3], [CH2SiMe2C(SiMe3)2YbC(SiMe3) 2SiMe2CH2], (29Si, 119Sn, 171Yb), [Yb(THF)6][{η8-1,3,6-(Me3Si) 3C8H5}2Ce]2, (29Si, 171Yb), [Yb(4,5-dihydro-2H-benz[g]imidazole)2 (DME)2], (171Yb), and [(η5-C5 H5)2Th(C=CR)-{C(SiH2Ph)=CHR}], (29Si).

2.3 Complexes of Group 4 – The diffusion coefficients of zirconocene–borate ion pairs have been determined by PFG NMR spectroscopy. A detailed structural investigation of meso-ethylenebis (4,7-Me2-l-indenyl)ZrMe2 has been performed using COSYgs, NOESY, HBMCgs and HSQCgs NMR spectra. NOE has been used to map the conformation of [(η5-C5Me4CMe2 -Pri)2MCl2], M = Ti, Zr, Hf. NMR data have also been reported for [TiH-{(Me3SiNCH2CH2) 2NSiMe3}]2, (29Si), [(η5-C5H5)2ZrH{(μ-H) 2BC4H8}], (11B), (9, (11B), [TiMeCl3], (35Cl, 49Ti), [Ti(CH2Ph)(R7Si7O12)], (29Si), [(η5-C5H4SiMe3) Ti(C [equivalent to] CSiMe2C [equivalent to] CSiMe3)2], (29Si), [(η5-C5H4CMe2 NMe2)-(η5-C5H5)ZrMe2], (15N), (8), (11B), [(η5-C5 H4SiMe3)2Ti(η2-Me3 SiC [equivalent to] C-SiMe3)], (29Si), (9), (29Si), [(η5-C5Me4SiMe2NBut) Ti(1,3-pentadiene)·B-(C6F5)3], (11B), [{(η5-C5H4)2BN(SiMe3) 2} TiCl(NMe2)], (11B), [{η5-l,2,5, 6-(Me3Si)4-4-[(η5-C5H5) Fe(η5-C5H4)]C6H2} Ti(η5-C5H5)2], (29Si), [{(2,6-Pri2C6H3)NSiMe3} 2{ (η5-C5Me5)Ti}2 (NH)6], (29Si),[(η5-C5H5 BOR)2ZrCl2], (11B), [(η5-C5 H5BNR2)2MCl2], (M = Ti, Zr, Hf; 11B), [(η5-C5Me5)Al] -[MePhB(η5-C5H4)2ZrCl2], (11B, 27Al), [(η5-1-C9H8 BNPri2)2ZrCl2], (11B), [(η5-C5Me5)M(-C3H3SBN Pri2)], (M = ZrCl2, Ru; 11B), [(η5-C13H8SiMe2N-But) ZrCl2], (14N, 15N, 29Si), [(η5-1-Pri2NBC9H7) (η5-C5Me5)ZrCl2], (11B), (10), (M = Ti, Zr; 11B), [CH2(CH2NSiMe3) 2ZrCl2(THF)2], (29Si), [HC{Si-Me2N(C6H4-4-Me)}3ZrCl4 (LiOEt2)2], (29Si), [MeSi(SiMe2NR) 3MX], (M = Ti, Zr, Hf; 29Si), [MTi(OCH2But) 5]2, (M = Li, Na, K; 6Li, 7Li, 17O, 23Na, 39K), [Ti11O13 (OPri)18], (17O), [Ti17O24 (OPri)20], (17O), and [Zr6BCl18] 5-, (11B).