The crystal structures of three series of clathrate compounds with organic guest molecules G have been determined, Cd(CN),-G, [CdM(CN),]*2G ( M = Hg or Zn) and "Me,-G][CuM(CN) ( M = Cd or Zn).12.767(2) A for CCI,CF,, depending on the molecular size and orientation of the guest in the cavity. In the second series the space group F d m is unchanged upon 50% substitution of Cd in the first with Hg or Zn owing to the random distribution of the tetrahedral centres; the lattice parameter varies little when M = Hg, but when M = Zn a = 12.243(2) A, a decrease of 0.5 A from the value for Cd(CN),*CCI,. The anionic host in the third series accommodates the N M e + guest together with neutral CCI,; the lattice parameter of the cubic F43m unit cell decreases by ca. 0.6 in comparison with the values in the first two series. The X-ray data for 24 single crystals are discussed in terms of the crystallographic discrimination between C and N of the linking CN groups and the orientation of the guest molecules, in particular of the tetrahedral and pseudo-tetrahedral guest molecules, in the cavity approximating to a tetrahedron.

No abstract

No abstract

113Cd magic angle spinning NMR, with and without 1H cross-polarisation and decoupling, has been used to study a number of Hofmann-type clathrates and related compounds. The 113Cd chemical shift shows a great sensitivity to the environment of Cd, even for complexes with closely related structures. The presence of five resonances due to Cd surrounded by CxN(4–x) (where x = 0 to 4) in Cd(CN)2 and Cd(CN)2•C6H12 indicates a static disorder of the CN groups, which makes these materials orientational glasses. Keywords: 113Cd NMR, Hofmann-type clathrates, Cd(CN)2, disorder, orientational glass.

Bis(3-cyano-pentane-2,4-dionato) (CNacac) metal complex, [M(CNacac)(2)], which acts as both a metal-ion-like and a ligand-like building unit, forms supramolecular structures by self-assembly. Co-grinding of the metal acetates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with CNacacH formed a CNacac complex in all cases: mononuclear complex was formed in the cases of Mn(II), Cu(II) and Zn(II), whereas polymeric ones were formed in the cases of Fe(II), Co(II) and Ni(II). Subsequent annealing converted the mononuclear complexes of Mn(II), Cu(II) and Zn(II) to their corresponding polymers as a result of dehydration of the mononuclear complexes. The resultant Mn(II), Fe(II), Co(II), Ni(II) and Zn(II) polymeric complexes had a common 3 D structure with high thermal stability. In the case of Cu(II), a 1 D polymer was obtained. The Mn(II), Cu(II) and Zn(II) polymeric complexes returned to their original mononuclear complexes on exposure to water vapour but they reverted to the polymeric complexes by re-annealing. Co-grinding of metal chlorides with CNacacH and annealing of the mononuclear CNacac complexes prepared from solution reactions were also examined for comparison. [Mn(CNacac)(2)(H(2)O)(2)], [M(CNacac)(2)(H(2)O)] (M=Cu(II) and Zn(II)) and [M(CNacac)(2)](infinity) (M=Mn(II), Fe(II) and Zn(II)) are new compounds, which clearly indicated the power of the combined mechanochemical/annealing method for the synthesis of varied metal coordination complexes.