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 n.m.r. spectroscopy is used are only included when the 1H n.m.r. spectra make a non-routine contribution, but complete coverage of relevant papers is still attempted where nuclei other than proton are involved. In view of the greater restrictions on space, and the ever growing numbers of publications, many more papers in marginal areas have been omitted. This is especially the case in the sections on solid-state n.m.r. spectroscopy, silicon and phosphorus.

A number of reviews have appeared including 'N.m.r. spectroscopy - a physical method in inorganic analytical chemistry', 'High resolution metal n.m.r. spectroscopy of organometallic compounds', which includes 25Mg, 27Al, 49Ti, 57Fe, 59CO, 61Ni, 91Zr, 103Rh, and 195Pt n.m.r. spectroscopy, 'Transition metal n.m.r. spectroscopy - a probe into organometallic structure and catalysis', which contains examples of 57Fe, 59CO and 103Rh n.m.r. spectroscopy of mono- and di-olefin complexes, 'Applications of transition metal n.m.r. spectroscopy in coordination chemistry', 'Homonuclear cluster compounds of platinum', which contains a useful review of 13C, 31P, and 195Pt chemical shifts and coupling constants, 'Multinuclear n.m.r.', 'N.m.r. of polyoxometallates', which contains examples of 1H, 17O, 19F, 27Al, 31P, 51V, and 183W n.m.r. spectrossopy, 'Measurement of spin coupling constants to quadrupolar nuclei via relaxation studies', 'N.m.r. approaches to the characterisation of the interaction of metal ions with proteins', 'N.m.r. and the Inorganic composition of plants', which contains examples of 1H, 13C, 15N, 19F, 23Na, 33S, 35Cl, and 39K n.m.r. spectroscopy, 'Physical Bioinorganic Chemistry Series, Vol. 3: n.m.r. of paramagnetic molecules in biological systems', and 'Application of multinuclear magnetic resonance to the perfused heart'.

A number of papers have been published which are too broadly based to fit into a later section and are included here. A set of substituent constants for alkyl groups has been calculated and shown to be useful in correlating the chemical shifts of nuclei. It was used for 13C, 14N, 15N, 17O, 19F, 29Si, 31P, 35Cl, 75AS, 77Se, 113Cd, 125Te and 199Hg chemical shifts. 13C n.m.r. spectroscopy has been used to investigate the complexation of [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] by MgBr2, TiCl4 or SnCl4. Correlations between 6(31P) and steric parameters of phosphametallacycloalkanes have been investigated. The torsional angle effect proved to be the dominant factor. 13C chemical shifts of DMSO complexes of Ru(II), Rh(III), and Pt(II) have shown that the direction of the methyl 13C resonance shift on complexation is a reliable guide to the mode of coordination. 13C chemical shifts have been reported for a wide range of metal complexes of N-salicyl-N'-2-furanthiocar-boxy hydrazine, hydroquinones and 12,17-Me2-1,5,9,12,17-penta-azabicyclo[7.5.5]nonadecane. 19F, 77Se, and 125Te chemical shifts of SF6, SeF6, TeF6, and WF6 have been measured as a function of density and temperature in the pure liquid and dilute gas. Isotope shifts were observed in the 19F n.m.r. spectrum. 19F, 77Se, 125Te, and 195Pt chemical shifts Of SF6, SeF6, TeF6, WF6, [PtC16]2- and [PtBr6]2- have been interpreted in terms of rovibrational averaging. Tissue has been investigated using 14N, 35Cl, and 39K n.m.r. spectroscopy.

2 Stereochemistry

This section is subdivided into ten parts which contain n.m.r. information about Groups IA and IIA and transition-metal complexes presented by Groups according to the Periodic Table. Within each Group, classification is by ligand type.

Complexes of Groups IA and IIA. — The nuclear shielding differences between gaseous metal ions and neutral atoms have been calculated for Li to Cs by combining Hartree-Fock calculations with electron-electron correlation corrections determined from experimental ionization potentials. The results were compared with 23Na, 39K, 87Rb, and 133Cs n.m.r. data. 1H and 6Li n.m.r. spectroscopy has been used to investigate [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], M = B, Al, Ga, In. 6Li-{1H) n.O.e. was used to determine the Li-H distances in solution. Similarly 1H-{6Li} n.O.e. was observed in [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], and PhNC4H3Li (tmeda). 13C n.m.r. data were also reported. 7Li n.m.r. studies of some cryptated lithium carbanions have shown that Li+ is in the cryptate cavity. The 6Li/7Li ratio in lithium salts has been determined by n.m.r. spectroscopy. Direct measurements of the 23Na T1 for Na-, coupled with 13C and 23N chemical shift data have been used to show that Na- in solution is behaving as if it were in the gas phase. 1H and 13C n.m.r. data have shown that BunK is monomeric. N.m.r. data have also been reported for some lithium benzyls (6Li, 7Li, 13C), (Ph2P)2CHLi.tmeda (13C), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (7Li), imidolithium compounds (7Li), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (31P), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (31P), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (13C, 23Na), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (13C), NaClO4 complexed by a tetraoxatetraaza lipophilic cage ligand (13C), and M-[M(crown)]+ (M = Na, Rb, Cs; 23Na, 87Rb, 133Cs).

Donor-acceptor complexes of magnesocene with Lewis bases have been identified by 13C and 25Mg n.m.r. spectroscopy. 1H n.m.r. spectroscopy has been used to investigate the structure of bacteriochlorophyllide d dimer. 31P n.m.r. spectroscopy has been used to investigate the thermal products from [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] N.m.r. data have also been reported for fluorinated O-diketonate complexes of beryllium (9Be), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (13C), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (27Al), [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (13C), and [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (31P).

Complexes of Groups IIIA and IVA, The Lanthanides, and Actinides. Reviews entitled 'Chemical n.m.r....