STRUCTURES OF ENA-POLY[(NITRATO-O,O')-SILVER(I)-MU-(DI-2-PYRIDYL KETONE-N-N')] AND DI-2-PYRIDYL KETONE

An X-ray structural analysis of tena-poly[(nitrato-0,0')silver(I)-mu-( di-2-pyridyl ketone-N..N)] (I) and di-2-pyridyl ketone (II) [2-(2-pyri dinecarbonyl)pyridinium tetrafluoroborate] revealed the first two exam ples of di-2-pyridyl ketone (DPK) where hydration of the carbonyl func tion has not occurred. In compound (I), the crystals were found to con sist of Ag(DPK)+ repeating units, in which Ag+ attains a distorted tet rahedral coordination environment. By coordinating through the two pyr idyl N atoms, DPK is observed to bridge separate Ag+ cations resulting in a non-cross-linked metal containing an extended structure. Single crystals of compound (II) were found to contain monoprotonated DPK mol ecules balanced by disordered BF4- anions. Protonation of the pyridine N atom is likely to be influential in establishing the planarity of t he molecule, permitting the formation of an additional six-membered ri ng. The proton bonded to the pyridine N atom is disordered between the two rings with site occupancy factors of 0.70 and 0.30, respectively.