FORMATION AND X-RAY-ANALYSIS OF THE SUPRAMOLECULAR SYSTEM OBTAINED BYTHE COMPLEXATION OF -9,10-DIPHENYL-2,5,8,11,14,17-HEXAOXAOCTADEC-9-ENE WITH SODIUM THIOCYANATE - A NEW COORDINATION TYPE FOR SCN-

The synthesis and X-ray structure of -9,10-diphenyl-2,5,8,11,14,17-hex aoxaoctadec-9-ene 1 and that of its complex with sodium thiocyanate ar e described. The free ligand is centrosymmetric with the phenyl ring t wisted out of the ethylenic plane by 39-degrees and a rather extended conformation of the polyether chain. The complex of 1 with NaSCN has b een obtained; its solid state structure is quite unique. There are two (1A and 1B) independent supramolecular systems 1-2NaSCN.2H2O with sim ilar geometries in the asymmetric part of the unit cell. Each system i s arranged in infinite independent chains with 'organic' and 'inorgani c' parts that alternate. In one of these systems (1B), disorder of the C=C double bond is observed. In each complex unit, the polyether side arms in the trans position are coordinated each to a different Na+. T he conformation of the polyether chain is (ag+/-a)(g-/+g-/+a) in three cases but the same as in the free ligand (ag+/-a)(ag+/-g+/-) in the f ourth. Both Na+ cations have a sixfold octahedral coordination: two O of the polyether, three N of the SCN- and one O of a water molecule ar e the ligating atoms of Na(1) while one N of an anion is replaced by a second water molecule for Na(2). In this complex, one observes a brid ging of one SCN between two cations and even between three cations for the second SCN-; this last kind of threefold bridging has never been reported before for the thiocyanate anion.