Abstract
In the title compound, [Fe(CH(3)CN)(3)(C(29)H(27)N(5)OP(2))](BF(4))(2)·2CH(3)CN, the Fe(II) ion is octa-hedrally coordinated by a meridionally chelating tridentate pincer-type PNP ligand derived from 2,6-diamino-4-eth-oxy-1,3,5-triazine and by three acetonitrile mol-ecules. The four Fe-N bond lengths range from 1.9142 (12) to 1.9579 (11) Å, while the Fe-P bonds are 2.2452 (4) and 2.2506 (4) Å [P-Fe-P = 165.523 (14)°], consistent with Fe(II) in a low-spin state. Unlike related Fe PNP complexes based on 2,6-diamino-pyridine, the BF(4) anions are not hydrogen bonded to the two NH groups of the pincer ligand but show instead anion-π inter-actions with the triazine ring and acetonitrile mol-ecules in addition to ten C-H⋯F inter-actions. Most remarkable among these is an anion-π(triazine) inter-action with a short distance of 2.788 (2) Å between one F and the centroid of the π-acidic triazine ring. The corresponding shortest distance between this F atom and a triazine carbon atom is 2.750 (2) Å. The two NH groups of the pincer ligand donate N-H⋯N hydrogen bonds to the triazine N atom of a neighbouring complex and to an uncoordinated acetonitrile mol-ecule. This last mol-ecule is in a side-on head-to-tail association with the second uncoordinated acetonitrile at C⋯N distances of 3.467 (2) and 3.569 (2) Å. In contrast to several related compounds with diamino-pyridine- instead of diamino-triazine-based PNP ligands, the title crystal structure is remarkably well ordered. This suggests that the diamino-triazine moiety exerts notable crystal structure stabilizing effects.