Systematic Structural Coordination Chemistry of p-tert-Butyltetrathiacalix[4]arene: Further Complexes of Lanthanide Metal Ions

Extension of previous work on the lanthanide(III) ion complexes of p-tert-butyltetrathiacalix[4]arene has led to a variety of structurally characterised species containing oxo-, hydroxo- and aqua-ligands presumably derived from water present in the preparative medium, along with the thiacalix-arene in various stages of deprotonation. The overall stoichiometry of some species is remarkably complicated due to the presence of simple anions and multiple solvents. Simplest is the binuclear complex [(mu-H2O){Ln(O-dmf)(2)](2)(HL center dot dmf)(2)]center dot nS (dmf = dimethylformamide) (1Ln, Ln = Sm (nS = 2dmf), Eu (nS = 1.5dmf center dot 2MeCN)], also the best-defined of all the arrays studied. The heaviest lanthanides give trinuclear Ln(OH)(3)center dot 2Ln(LH)center dot xdmf center dot yH(2)O (2Ln, Ln Yb, Lu), while both oxo and hydroxo species are isolable with Eu: trinuclear Eu3O-(L)(LH)(LH4)center dot 1.3dmf (3) and tetranuclear Eu4O(OH)(2)(L)(LH2)(2)(LH4)center dot 1.2dmf (9), both somewhat atypical species containing uncoordinated thiacalixarene molecules within the lattice. Anion (NO3, ClO4) coordination, as in the tri- and tetranuclear species, 4-6Ln, 9,10Ln, 11Ln, 12, seems especially favoured for the lighter lanthanides. In these arrays, the Ln(3) and Ln(4) aggregates are triangular or (quasi-)square-planar, except for Gd4O2(LH2)(4)center dot 2H(2)O center dot 2MeOH center dot 2dmf center dot 3.375CH(2)Cl(2) (12), where there is a Z-disposition. Most common is an Ln(3)O core, which spans the gamut of Ln in three sets of crystal forms with cells of similar dimensions: for Ln = La center dot center dot center dot Nd, Ln(3)(OH)-(NO3)(4) (LH2)(2)center dot 4.5dmf (5Ln) (space group C2/m), and Sm center dot center dot center dot Lu, Ln(3)O(NO3)(LH)(2)center dot 4H(2)O-2dmso center dot 2MeCN center dot 3py (6Ln) (space group P2(1)/n), conformity with crystallographic symmetry entails disorder of the Ln atoms; in a further form of lower symmetry Pn, (pyH)Ln(3)O(NO3)(2)(LH)(2)center dot 2MeCN center dot xH(2)O center dot ydmso center dot 1.5py center dot MeOH (7Ln, Ln = La, Ce), with no imposed crystallographic symmetry, some disorder persists, but none is found in the crystallographically unrelated form of 8Pr, Pr3O(NO3)(LH)(2)center dot 16H(2)O center dot 2MeCN center dot 5py. Ln(4)(OH)(NO3)(3)(L)(2)center dot 8dmf center dot 2dmso center dot 3H(2)O (10Ln, Ln = Pr center dot center dot center dot Gd, previously defined for Nd) has a square-planar Ln(4)O array sandwiched between a pair of L ligands, with a similar form found for Ln(4)O(ClO4)(2)(L-2)center dot xdmf center dot yH(2)O (11Ln, Ln = La center dot center dot center dot Nd).