ANDREWS, P C and Mulvey, Robert and CLEGG, W and REED, D (1990) X-ray crystallographic studies and dynamic 1H NMR spectroscopic studies of the novel sodium aza-allyl monomer [PhC(H)NC(H)Ph]Na · PMDETA: A discrete contact ion-pair structure held together by a short NNa bond, and showing close (ortho-Ph)CH ··· Na contacts in both solid state and solution. Journal of Organometallic Chemistry, 386 (3). pp. 287-297. ISSN 0022-328XFull text not available in this repository. (Request a copy from the Strathclyde author)
[PhC(H)NC(H)Ph]Na · PMDETA (1) (PMDETA = (Me2NCH2CH2)2NMe), exhibits a contact ion-pair arrangement in the crystal, with the complexed metal cation bound to the nitrogen centre of the aza-allyl fragment (NNa bond length, 2.384(2) Å). Further close contacts exist between the sodium and one ortho-C from each phenyl ring (distances 3.133(4) and 3.166(4) Å). Variable-temperature 1H NMR spectroscopic studies indicate that 1 adopts a remarkably similar structure in tetrahydrofuran-d8 solution. Thus, at −50°C the restricted rotation about each C(ipso)C(benzylic) bond results in the appearance of two distinct resonances each for both the ortho- and meta-H's. From their coalescence temperatures the energy barrier to rotation has been estimated (12.8 kcal mol−1). Evidence that this rigid solution conformation mimics the crystal structure in having short ortho-CH ··· Na distances comes from the exceptionally large chemical shift difference (1.05 ppm) associated with the dual ortho-H signals.
|Keywords:||crystallographic studies , crystallography , crystal structures, Physical and theoretical chemistry, Materials Chemistry, Biochemistry, Organic Chemistry, Physical and Theoretical Chemistry, Inorganic Chemistry|
|Subjects:||Science > Chemistry > Physical and theoretical chemistry|
|Department:||Faculty of Science > Pure and Applied Chemistry|
|Depositing user:||Pure Administrator|
|Date Deposited:||14 Feb 2012 12:58|
|Last modified:||05 May 2016 00:19|