TY - JOUR
T1 - Organometallic complexes for nonlinear optics. 15. Molecular quadratic hyperpolarizabilities of trans -bis {bis(diphenylphosphino)methane}ruthenium σ-aryl- And σ-pyridyl-acetylides
T2 - X-ray crystal structure of trans-[Ru(2-C=CC5H3N-5-NO2)Cl(dppm) 2]
AU - Naulty, Raina H.
AU - McDonagh, Andrew M.
AU - Whittalla, Ian R.
AU - Cifuentes, Marie P.
AU - Humphrey, Mark G.
AU - Houbrechts, Stephan
AU - Maes, Joachim
AU - Persoons, André
AU - Heath, Graham A.
AU - Hockless, David C.R.
N1 - ©1998ElsevierScienceS.A.All rights reserved
PY - 1998/7/30
Y1 - 1998/7/30
N2 - The complexes trans-[Ru(2-C≡CC5H3N-5-R)Cl(dppm)2] [R = H (6), NO2 (7)] have been prepared and 7 has been structurally characterized; comparison with the structural study of trans-[Ru(4-C≡CC6H4NO2)Cl(dppm) 2] (3) reveals a decrease in Ru-C(1) distance and increase in Ru-Cl(1) distance, consistent with stronger σ-bonding by the nitropyridylalkynyl ligand in 7 compared to the nitrophenylalkynyl ligand in 3. Electrochemical data for 3, 6, 7, precursor dichloro complexes [RuCl2(dppm)2] [cis (1a), trans (1b)], and related alkynyl complexes trans-[Ru(4-C≡CC6H4R)Cl(dppm)2] [R = H (2), 4-C6H4NO2 (4), (E)-4-CH=CHC6H4NO2 (5)] have been determined by cyclic voltammetry. Introduction of nitro substituent in progressing from 2 to 3 or 6 to 7 leads to a substantial increase in EoRuII/III, most of which is lost on chain-lengthening the alkynyl ligand in progressing from 3 to 4 or 5. Replacement of phenyl by pyridyl in progressing from 2 to 6 or 3 to 7 results in a 0.1 V increase in EoRuII/III. The optical spectra of representative complexes have been examined. Introduction of a nitro substituent onto the phenylalkynyl ligand, in progressing from 2 to 3, results in a substantial (ca. 11000 cm-1) red-shift in the intense MLCT band of the RuII-C≡C-Ar-NO2 moiety. Complexes 3, 4 and 5 exhibit sizable solvatochromic shifts, suggestive of significant optical nonlinearities. Quadratic hyperpolarizabilities for 2-7 were determined by hyper-Rayleigh scattering (HRS) at 1064 nm; measurements are consistent with an increase in βHRS upon incorporation of nitro substituent (progressing from 2 to 3 or 6 to 7), chain-lengthening the alkynyl ligand (progressing from 3 to 4 and then to 5) and replacing phenyl by pyridyl in progressing from 2 to 6, general trends that are maintained with the two-level-corrected data, and which parallel shifts in λmax to low energy. The observed and two-level-corrected βHRS values for 7 are lower than expected; it is perhaps significant that λmax for 7 is close to the second-harmonic.
AB - The complexes trans-[Ru(2-C≡CC5H3N-5-R)Cl(dppm)2] [R = H (6), NO2 (7)] have been prepared and 7 has been structurally characterized; comparison with the structural study of trans-[Ru(4-C≡CC6H4NO2)Cl(dppm) 2] (3) reveals a decrease in Ru-C(1) distance and increase in Ru-Cl(1) distance, consistent with stronger σ-bonding by the nitropyridylalkynyl ligand in 7 compared to the nitrophenylalkynyl ligand in 3. Electrochemical data for 3, 6, 7, precursor dichloro complexes [RuCl2(dppm)2] [cis (1a), trans (1b)], and related alkynyl complexes trans-[Ru(4-C≡CC6H4R)Cl(dppm)2] [R = H (2), 4-C6H4NO2 (4), (E)-4-CH=CHC6H4NO2 (5)] have been determined by cyclic voltammetry. Introduction of nitro substituent in progressing from 2 to 3 or 6 to 7 leads to a substantial increase in EoRuII/III, most of which is lost on chain-lengthening the alkynyl ligand in progressing from 3 to 4 or 5. Replacement of phenyl by pyridyl in progressing from 2 to 6 or 3 to 7 results in a 0.1 V increase in EoRuII/III. The optical spectra of representative complexes have been examined. Introduction of a nitro substituent onto the phenylalkynyl ligand, in progressing from 2 to 3, results in a substantial (ca. 11000 cm-1) red-shift in the intense MLCT band of the RuII-C≡C-Ar-NO2 moiety. Complexes 3, 4 and 5 exhibit sizable solvatochromic shifts, suggestive of significant optical nonlinearities. Quadratic hyperpolarizabilities for 2-7 were determined by hyper-Rayleigh scattering (HRS) at 1064 nm; measurements are consistent with an increase in βHRS upon incorporation of nitro substituent (progressing from 2 to 3 or 6 to 7), chain-lengthening the alkynyl ligand (progressing from 3 to 4 and then to 5) and replacing phenyl by pyridyl in progressing from 2 to 6, general trends that are maintained with the two-level-corrected data, and which parallel shifts in λmax to low energy. The observed and two-level-corrected βHRS values for 7 are lower than expected; it is perhaps significant that λmax for 7 is close to the second-harmonic.
KW - Acetylide
KW - Alkynyl
KW - Hyperpolarizability
KW - Nonlinear optics
KW - Ruthenium
UR - http://www.scopus.com/inward/record.url?scp=0001443363&partnerID=8YFLogxK
U2 - 10.1016/S0022-328X(98)00573-7
DO - 10.1016/S0022-328X(98)00573-7
M3 - Article
SN - 0022-328X
VL - 563
SP - 137
EP - 146
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 1-2
ER -