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NMR studies of some solid silver and tin compounds

Amornsakchai, Pornsawan (2004) NMR studies of some solid silver and tin compounds. Doctoral thesis, Durham University.



A solid-state NMR study of a range of tin- and silver-containing compounds has been carried out in order to obtain information on the chemical shifts, coupling constants and relaxation times. The results are discussed in relation to the crystal structures, where known, and some crystallographic information obtained in cases with no previously-known structures. For tin-containing compounds, solid-state (^119)Sn and (^31)P NMR comprise the majority of this work. Nevertheless, (^13)C NMR studies have been also carried out to assist the structure determination. Six Sn(II) compounds have been examined, including three which also contain phosphorus. Spinning sideband analysis has been achieved for (^119)Sn (in some cases (^31)P), giving information on the shielding tensors. Satellite peaks observed on the (^119)Sn NMR spectra of SnHPO(_3) and SnHP0(_4) reveal that the spectra contain information about indirect Sn(_2)Sn coupling. Since surprisingly large values of 2600 ±200 Hz and 4150 ± 200 Hz are found for SnHPO(_3)and SnHPO(_4), respectively, the calculated relative intensities of the satellites and the results of a single Hahn echo experiment have been discussed in detail. The relatively isolated ((^1)H,(^31)P) spin pair in solid SnHPO(_3) have been extensively investigated in this work, though the systems are rather complicated. The (^1)H and (^31)P spectra display an intensity distribution of the spinning sidebands, which is the characteristic of an interplay of shielding, dipolar and indirect coupling tensors dominated, by the strong dipolar interactions. A single Hahn echo experiment was employed to reveal indirect spin-spin coupling ((^1)JPH). Strong oscillatory polarization transfer by dipolar interaction occurs during short contact times on moderately fast magic-angle spinning and the P,H distances were extracted (including for SnHPO(_4)).Rather complicated (^1)H NMR spectra under (^31)P continuous-wave decoupling arises from a second-order recoupling of the heteronuclear dipolar-coupling tensor and the shielding tensor of ^'P, leading to line-splittings and broadenings in the {(^31)P}(^1)H spectra. Additionally, measurement of (^1)H and (^31)P relaxation times has been undertaken, producing results which were expected to follow the behaviour characteristic of an isolated two-spin system, but anomalies were observed. Various nuclei, such as (^13)C, (^15)N, (^31)P and (^109)Ag, in silver-containing compounds have been studied, and provide information on indirect spin-spin interactions, (^1)J((^109)Ag (^14)N) and (^1)J((^109)Ag(^15)N). The (^109)Ag NMR spectra for [Ag(NH(_3)(_2))(_2)X where X = SO(_4), SeO(_4), NO(_3)show spinning sideband manifolds, which are typical for systems with moderately large shielding anisotropy. Other silver compounds namely [Ag(R)(_2)]NO(_3) where R = pyridine, collidine, 2-picoline, quinoline and AgY where Y = HPO(_4) and PO(_4), have been investigated to give as much complementary information about the chemical shifts as possible.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:2004
Copyright:Copyright of this thesis is held by the author
Deposited On:09 Sep 2011 10:03

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