Effect of Coordination Modes on the Tunable Luminescence of 1,10‐Phenanthroline‐Based Complexes

Abstract

Two luminescent compounds [Zn(L) 2 ](ClO 4 ) 2 (1) and[Na(L)(MeOH)(μ-ClO 4 )] n (2) are obtained from the reactions of 2,9-bis(carbomethoxy)-1,10-phenanthroline (L) with corresponding hydrated perchlorate salts in MeOH. Their crystal structures are determined by X-ray crystallography. 1 is a mononuclear 8-coordinate Zn 2+ compound and 2 is a ClO 4 − -bridged 1D polymer, where the ligand L exhibits different coordination modes (carbonyl O vs methoxyl O coordination). Although the luminescence of these two compounds originates similarly from the ligand-centered π →π* transitions, it is interesting to note that their emissions are significantly influenced by the different coordination modes of L. The relationship between their structures and emission properties has been investigated in detail. The stability and energy difference between these two coordination modes in these two compounds are analyzed by Time-dependent density functional theory (TD-DFT) calculations.

Structural and spectroscopic characterization and DFT studies of 2-amino-1,10-phenanthrolin-1-ium chloride

“…We have an ongoing interest in the synthesis of azabridged bis-1,10-phenanthroline derivatives [10][11][12], mainly due to their significant biological activity of the corresponding metal complexes in which the planar and also rigid structure of 1,10-phenanthroline (phen) can either intercalate or bind to the grooves of DNA or RNA [13][14][15][16][17][18][19][20]. Therefore, the design and synthesis of new derivatives of phen with extended properties have gained a significant attention by many researchers [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. We have previously reported an alternative strategy to synthesize a series of phen derivatives [37].…”