TY - JOUR
T1 - Organometallic Complexes for Nonlinear Optics. 2.1 Syntheses, Electrochemical Studies, Structural Characterization, and Computationally-Derived Molecular Quadratic Hyperpolarizabilities of Ruthenium σ-Arylacetylides
T2 - X-ray Crystal Structures of Ru(C≡CPh)(PMe3)2(η-C5H5) and RU(C≡CC6H4NO2-4)(L)2(η-C5H5) (L = PPh3, PMe3)
AU - Whittall, Ian R.
AU - Humphrey, Mark G.
AU - Hockless, David C.R.
AU - Skelton, Brian W.
AU - White, Allan H.
PY - 1995/8
Y1 - 1995/8
N2 - A series of complexes Ru(CΞCC6H4R-4)(PR'3)2(η5-C5H5) (R = H, R' = Ph, 1a; R = H, R' = Me, 1b; R = NO2, R' = Ph, 2a; R = NO2, R' = Me, 2b) has been synthesized by reaction of RuCl(PR'3)2(η-C5H5) with 4-HCΞCC6H4R and deprotonation of the intermediate metal vinylidene complex. The complexes are of the donor-acceptor type, giving enhanced second-order nonlinear optical responses. Correlations of spectroscopic data are consistent with increased electron density at the metal upon increasing the donor strength of the phosphine and with decreased electron density at the metal upon increasing the acceptor strength of the acetylide ligand. Electrochemical data are consistent with an RuII/III couple for 1a,b, and 2a,b whose oxidation potentials vary strongly with the donor and acceptor strengths of ligands, and a NO2-centered LUMO for 2a,b. Enhanced solvatochromic responses are observed on replacement of 4-H by 4-NO2 on the acetylide ligand. Complexes 1b and 2a,b have been crystallographically characterized. Ru-C(1) distances for these complexes are among the shortest for ruthenium σ-acetylide complexes. Semiempirical calculations employing ZINDO were performed; the results are consistent with increased molecular quadratic hyperpolarizabilities for (i) increasing electron density at the metal center (replacing PPh3 by PMe3), (ii) increasing acceptor strength of the arylacetylide (replacing 4-H by 4-NO2), (iii) decreasing M-C(acetylide) bond length, and (iv) optimum orientation of the acetylide aryl group. Thus, the RuL2(η-C5H5) behaves as an efficient tunable donor group.
AB - A series of complexes Ru(CΞCC6H4R-4)(PR'3)2(η5-C5H5) (R = H, R' = Ph, 1a; R = H, R' = Me, 1b; R = NO2, R' = Ph, 2a; R = NO2, R' = Me, 2b) has been synthesized by reaction of RuCl(PR'3)2(η-C5H5) with 4-HCΞCC6H4R and deprotonation of the intermediate metal vinylidene complex. The complexes are of the donor-acceptor type, giving enhanced second-order nonlinear optical responses. Correlations of spectroscopic data are consistent with increased electron density at the metal upon increasing the donor strength of the phosphine and with decreased electron density at the metal upon increasing the acceptor strength of the acetylide ligand. Electrochemical data are consistent with an RuII/III couple for 1a,b, and 2a,b whose oxidation potentials vary strongly with the donor and acceptor strengths of ligands, and a NO2-centered LUMO for 2a,b. Enhanced solvatochromic responses are observed on replacement of 4-H by 4-NO2 on the acetylide ligand. Complexes 1b and 2a,b have been crystallographically characterized. Ru-C(1) distances for these complexes are among the shortest for ruthenium σ-acetylide complexes. Semiempirical calculations employing ZINDO were performed; the results are consistent with increased molecular quadratic hyperpolarizabilities for (i) increasing electron density at the metal center (replacing PPh3 by PMe3), (ii) increasing acceptor strength of the arylacetylide (replacing 4-H by 4-NO2), (iii) decreasing M-C(acetylide) bond length, and (iv) optimum orientation of the acetylide aryl group. Thus, the RuL2(η-C5H5) behaves as an efficient tunable donor group.
UR - http://www.scopus.com/inward/record.url?scp=0000706749&partnerID=8YFLogxK
U2 - 10.1021/om00008a050
DO - 10.1021/om00008a050
M3 - Article
AN - SCOPUS:0000706749
SN - 0276-7333
VL - 14
SP - 3970
EP - 3979
JO - Organometallics
JF - Organometallics
IS - 8
ER -