Synthesis and Structure of a Sodium Complex of an Aromatic β-Diketone and Pyrazolylpyridine

Abstract

Abstract:Reaction of NaH with a THF solution of Eu(BTA) 3 (pypzH) 3,pyridine] leads to the formation of the europium-free tetrasodium complex [Na 4 (pypzH) 2 (µ 4 -BTA) 2 (µ 2 -BTA) 2 ]. Single-crystal Xray diffraction studies revealed the presence of a centrosymmetric Na + hybrid tetramer, which fully occupies the contents of the triclinic unit cell. The crystal structure contains two individual Na + cations, Na(1) and Na(2), which have highly irregular {NaN 2 O 3 } and {NaO 6 } local coordination environments, respectively. One of the key features is the presence of a central {Na 4 O 6 } core, which is unprecedented for Na + . Externally to this {Na 4 O 6 } cluster pyrazolylpyridine organic molecules are N,N-chelated to Na(1). Even though all of the organic residues contain aromatic rings, the crystal packing of individual centrosymmetric tetrasodium [Na 4 (pypzH) 2 (µ 4 -BTA) 2 (µ 2 -BTA) 2 ] molecular moieties is essentially driven through geometrical aspects combined with weak C-H···π interactions, rather than the expected a priori π-π interactions. The material also contains classical strong hydrogen bonds, even though these do not directly contribute to the packing driving forces.