Publisher Summary Tin (Sn) compounds are well-recognized both in basic research and in industrial applications. Tin NMR spectroscopy includes three magnetically active tin isotopes namely, 115Sn, 117Sn , and l19Sn. However, most tin NMR parameters refer to the 119Sn nucleus owing to its properties such as abundance, magnetic moment, and NMR frequency. This chapter describes: (1) the compilation and updation of 119Sn chemical shifts (δ 119Sn) from studies on organotin compound and inorganic tin compounds, (2) indirect nuclear spin-spin couplings, (3) relaxation mechanisms concerning the 119Sn nucleus, and (4) experimental details for 1I9Sn-NMR measurements. It is observed that with modem equipment there are, in principle, no serious experimental difficulties in observing 119Sn resonances either directly or by heteronuclear double resonance. δ 119Sn data, available for all kinds of tin compounds, significantly allows using this parameter in an empirical way in order to find models for the qualitative interpretation of δ 119Sn. This also applies to couplings involving the l19Sn nucleus, which serve as a sensitive tool in the discussion of structure and bonding. All 119Sn-NMR parameters of tin compounds largely concern measurements in the liquid state.

119Sn-NMR Parameters

A brief analysis is presnted of the current understanding of substituent perturbations in monosubstituted benzenes as determined by substituent induced carbon chemical shifts. A critical tabulation of the four substituent chemical shifts is given for c. 700 monosubstituted benzenes.

13C substituent effects in monosubstituted benzenes

Coordination compounds of copper, nickel and iron with Schiff bases derived from hydroxynaphthaldehydes and salicylaldehydes

Carbon—hydrogen spin—spin coupling constants

Isotope effects in nuclear shielding

Carbon-13 Fourier transform NMR study of the organotin compounds. II. Karplus-type dependence of vicinal tin-119-carbon-13 coupling

The natural abundance C NMR spectra of a number of substituted naphthalenes have been obtained and assigned by utilization of some or all of the following criteria: (a) specific H incorporation and spectral consequences thereof, (b) fully proton coupled spectra, (c) fluoro substitution, and (d) approximate additivity of substituent effects on chemical shifts for certain dispositions. For crucial sets of 1-and 2-substituted naphthalenes, spectra have been obtained under dilute conditions in chloroform and acetone, and the substituent chemical shifts have been treated by the dual substituent parameter equation (DSP analysis) to provide further insight into the transmission of substituent effects in the naphthyl system.

Carbon-13 Nuclear Magnetic Resonance Examination of Naphthalene Derivatives. Assignments and Analysis of Substituent Chemical Shifts

Group IVb metalloidal substituent effects studied by carbon-13 nuclear magnetic resonance spectroscopy

13C chemical shift variations within a series of phenyl, furyl and thienyl Group IVB organometallics appear to be best understood in terms of the usual alkyl and aryl substituent effects on 13C chemical shifts and not variations in dπ ?pπ metal-aryl interactions. Large changes in 13C-metal scalar coupling constants have been observed suggesting that other factors besides the s-character of the carbon-metal bond is responsible in determining the coupling constant.

Carbon magnetic resonance studies of some phenyl, furyl and thienyl organometallics. Some comments on carbon-metal scalar coupling

The natural abundance, proton-decoupled carbon-13 spectra of 1-methylnaphthalene, 1-fluoronaphthalene, l-naphthonitrile and their 4-deutero analogues, as well as 2-naphthol and its 6-deutero analogue, have been recorded. Careful comparisons of the spectra of the deuterated and undeuterated compounds allow assignment, not only of the deuterated carbon, but also of the two ortho carbons (based on an upfield ‘two-bond’ deuterium isotope effect), as well as the two meta carbons (based on a significant J(CCCD) of ∼1 Hz) which causes substantial broadening). In the 1-naphthyl compounds, significant coupling between the deuterium (at C4) and C5 allows assignment of this latter carbon. Thus, the consequences of the introduction of one deuterium atom, together with results from off-resonance noise decoupling, permits assignment of most of the spectra. Tentative, but very likely assignments of the few remaining signals, can be made on the bases of chemical shifts and compressional effects. This approach could allow indirect assignment of an aryl carbon to which direct attachment of deuterium is difficult, due to directive effects of an existing substituent.

Maxwell Bullpitt

Papers

Carbon-13 Fourier transform NMR study of the organotin compounds. II. Karplus-type dependence of vicinal tin-119-carbon-13 coupling

Carbon-13 Nuclear Magnetic Resonance Examination of Naphthalene Derivatives. Assignments and Analysis of Substituent Chemical Shifts

Group IVb metalloidal substituent effects studied by carbon-13 nuclear magnetic resonance spectroscopy

Carbon magnetic resonance studies of some phenyl, furyl and thienyl organometallics. Some comments on carbon-metal scalar coupling

Carbon‐13 assignments in 1‐ and 2‐naphthyl compounds: Extensive benefits of deuterium substitution