The reaction of 2 phosphorylalkyl substituted 1,8 naphthyridines, viz., 2 [2 (diphenylphos phoryl)propan 2 yl] 1,8 naphthyridine (L 1 ) and 2 [2 (diphenylphosphoryl)ethyl] 1,8 naph thyridine (L 2 ), with lanthanide nitrates (Nd, Eu, or Lu) afforded complexes with the metal to ligand molar ratio of 1 : 1 and 1 : 2. Based on the IR and Raman spectroscopic data, it was found that the coordination of the ligands L 1 and L 2 in all complexes occurs through the P=O group and the nitrogen atoms of the naphthyridine moiety.In the past decade, the synthetic and coordination chemistry of 1,8 naphthyridine and its derivatives has at tracted great interest due to the diverse use of these com pounds and their complexes. 1,2 Among 1,8 naphthyridine derivatives, compounds containing coordinatively active substituents at position 2 or positions 2 and 7 are of partic ular interest. Coordination compounds of this family are used in metal complex catalysis, 3 some of these com pounds exhibit biological activity; 1,2,4 furthermore, some complexes have very interesting photophysical properties, 5 such as luminescence. 6 Although complexes with metal cations belonging to the majority of Groups of the Period ic Table have been investigated, 1,2,7 complexes with lan thanides have been studied to a much lesser extent. 8,9 At the same time, it is known that lanthanide complexes with organic polynitrogen and oxygen containing ligands are extensively studied and are used for the preparation of organic light emitting diodes (OLED). 10 The field of our research is the preparation of new 1,8 naphthyridine systems and the synthesis of the com plexes of these systems with lanthanides. Taking into ac count that tertiary phosphine oxides can form a strong coordination bond with many metals (including lan thanides) through the lone electron pair of the phosphoryl oxygen atom, we synthesized new phosphorus containing ligands, viz., monosubstituted phosphorylalkyl 1,8 naph thyridines. 11,12The coordination properties of this type of ligands were investigated using the example of the complex ation of 2 [2 (diphenylphosphoryl)propan 2 yl] 1,8 naphthyridine (L 1 ) and 2 [2 (diphenylphosphoryl)ethyl] 1,8 naphthyridine (L 2 ) containing linkers of differ ent length with lanthanide nitrates Ln(NO 3 ) 3 (Ln = Nd, Eu, or Lu).
ExperimentalThe solvents were purified and dried according to known pro cedures 13 and saturated with argon. The salts Nd(NO 3 ) 3 •6H 2 O, Eu(NO 3 ) 3 •5H 2 O (Fisher Scientific Company), and Lu(NO 3 ) 3 •xH 2 O (Aldrich) were used without additional purifi cation. The water content (x = 3) in commercial lutetium nitrate was determined experimentally.
[(Diphenylphosphoryl)propan yl] 1,8 naphthyridine (L 1 ) and [(diphenylphosphoryl)ethyl] 1,8 naphthyridine (L )were synthesized according to procedures described previously. 11,12Synthesis of lanthanide complexes 1-12 (general procedure). To a solution of a ligand (L 1 or L 2 ) (0.3 mmol) in chloroform (1-2 mL), a solution of stoichiometric amount (0.3 or 0.15 mmol) of Ln(NO 3 ) 3 •nH 2 ...