Nuclear magnetic resonance investigation of secondary valence forces. I. Intramolecular π coordination in aralkylmercury compounds

Crystal and molecular structure of (3,3'-dimethyl-2,2'-bipyridyl)methylmercury(II) nitrate; a complex that may have weak intramolecular π-coordination

“…The distance from Hg to the midpoint of the C(2')-N(I') bond is 3.13 A and is longer than the 3-05 A found for the distance of Hg to the midpoint of a C..-C bond in the phenyl ring in CIHgCH2CH(Me)OMeCH 2 (P-OMePh) where the presence of a ~r-interaction has been shown from conformational analysis by ~H NMR spectroscopy (Kiefer, Waters & Carlson, 1968). If a weak n-interaction is present in the solid state, it is apparently weaker than the Hg...O interactions as the methyl group bonded to Hg is bent away from the nitrate O atoms towards the second pyridyl ring, whereas if appreciable Hg.-.…”

“…A weak re-interaction does occur in some y-substituted propylmercury complexes, e.g. CIHgCH2C(Me )-(OMe)CH2(P-OMePh) which has Hg... Ph 3-05 /k (Kiefer, Waters & Carlson, 1968), and in order to determine whether weak z~-interactions occur in the chemistry of MeHg n we have determined the crystal and molecular structure of [MeHg(3,3'-dmbpy)lNO 3.…”

Weak intramolecular π coordination to methylmercury(II). Structure of (2-benzylpyridine)methylmercury(II) nitrate

“…Weak interaction between Hg and aromatic rings in organomercury compounds was first demonstrated by conformational analysis using IH NMR spectroscopy for 3-arylpropylmercurials and confirmed by a crystal structure of one of these, [C1HgCH2C(Me)(OMe)CH 2 (p-OMePh)], which has the Hg atom 3.05 A above one of the phenyl bonds (Kiefer, Waters & Carlson, 1968). The ~H resonances of MeHg I1 in [MeHglC, CH2Ph] (Rabenstein, Ozubko, Libich, Evans, Fairhurst & Suvanprakorn, 1974) suggesting that the methyl group is shielded by the presence of a nearby aromatic ring.…”

“…[C1HgCH2C(Me)(OMe)CH2(P-OMePh)] has the HgCH 2 proton resonance upfield of that for [C1HgCFI2C(Me)(OMe)CMe31 (Kiefer, Waters & Carlson, 1968).…”

Nuclear magnetic resonance coupling constants in tin in 3,3,3-trifluoropropyltin compounds

“…A peculiarity of tin-alkyl as well as of metal-alkyl compounds in general is that the vicinal metal-hydrogen coupling constant often exceeds the analogous geminal coupling constant.1 The short-range coupling constants have been related empirically to heats of complex formation,2 as well as to bond polarities3 and Taft substituent constants,4 and they have also been employed to determine tin hybridization and its variation with tin substituents.6 '6 The longer range coupling constants involving various nuclei in organometallic compounds have been used to probe the detailed geometry and conformation7 of molecules as well as to investigate weak intermolecular interactions. 8 We wish to report the various coupling constants we have obtained from the and 19F nmr spectra of 11 3,3,3-trifluoropropyl (PrF3) tin compounds. These compounds have three different types of coupling constants involving the tin nucleus (see Figure 1) and hence are especially rich in spin coupling information.…”