Synthesis, Crystal Structure, and Second‐Order Nonlinear Optical Properties of Ruthenium(II) Complexes with Substituted Bipyridine and Phenylpyridine Ligands

Unexpected High Second‐Order Nonlinear Optical Activity of Metal Complexes with Three‐Branched Hexadentate 2,2′‐Bipyridine Ligands

“…The structural motif of an electron‐donor–π‐bridge–electron‐acceptor ( d ‐π‐A) chromophore is achieved by a threefold dendritic structured compound and the addition of terminal 2,2′‐bipyridine (bpy) functions. Hexacoordinated bpy complexes appear attractive because intense metal‐ligand charge transfer transitions can affect a significant enhancement of the NLO properties . Coordination of conjugated ligands with metal atoms like Ru has resulted in a drastic enlargement of the NLO response .…”

“…All complexes reveal one strong absorption band in acetone at low energy (about 450–470 nm), which could be identified as metal‐ligand charge‐transfer band (MLCT) (Figure and Figure ). These results fit well with published data . The MLCT‐band of the ruthenium complex 5 was hypsochromically shifted (Δ =−359 cm −1 ) when changing the solvent to acetonitrile, whereas complex 6 experienced a weak bathochromic shift (Δ =45 cm −1 ).…”

“…Upon coordination of comparable single‐strand chromophores with Ru II ions, a similar strong SHG is observed to that already published . The single‐strand complexes 1 and 3 , with the L 1 ‐ligand demonstrate an increased first hyperpolarizability by a factor of 1.4 with respect to the L 2 ‐complexes 2 and 4 .…”

Tuning the dipolar second-order nonlinear optical properties of 5-π-delocalized-donor-1,3-di(2-pyridyl)benzenes, related cyclometallated platinum(ii) complexes and methylated salts

“…1--2 Among them, metal complexes are fascinating because they give additional flexibility, when compared to organic compounds, due to the presence of NLO--active charge--transfer transitions between the metal and the ligands, usually at relatively low energy and of high intensity, and tunable by virtue of the nature, oxidation state and coordination sphere of the metal center. 3--11 In particular, it appeared that the second--order NLO response of variously substituted phenylpyridines increases significantly upon cyclometallation, an effect that has given rise to cyclometallated Ru(II), 12 Ir(III) 13--23 and Pt(II) 23--24 complexes characterized by interesting NLO properties. Platinum(II) complexes bearing an N^N^C--cyclometallated 6--phenyl--2,2'--bipyridine constitutes another interesting NLO--active family.…”

(Super)alkali atoms interacting with the σ electron cloud: a novel interaction mode triggers large nonlinear optical response of M@P4 and M@C3H6 (M=Li, Na, K and Li3O)

“…Besides organic systems with a donor-π-acceptor arrangement, the metal-ligand compounds formed by incorporating transition metal into an organic complexant can also exhibit a large NLO response due to the occurrence of metal-to-ligand charge transfer (MLCT) [12][13][14]. For example, for ruthenium(II) complexes with substituted phenylpyridine ligand, the static first hyperpolarizability investigated by the experimental hyper-Rayleigh scattering technique is about 230 cm 5 esu -1 [13].…”