Syntheses, Electrochemical, Linear Optical, and Cubic Nonlinear Optical Properties of Ruthenium-Alkynyl-Functionalized Oligo(phenylenevinylene) Stars

Zhiwei Chen; Christopher J Jeffery; Mahbod Morshedi; Graeme J Moxey; Adam Barlow; Xinwei Yang; Bandar A Babgi; Gulliver T Dalton; Michael D Randles; Matthew K Smith; Chi Zhang; Marek Samoc; Marie P Cifuentes; Mark G Humphrey

doi:10.1002/cplu.201500220

Syntheses, Electrochemical, Linear Optical, and Cubic Nonlinear Optical Properties of Ruthenium-Alkynyl-Functionalized Oligo(phenylenevinylene) Stars

Chempluschem. 2015 Aug;80(8):1329-1340. doi: 10.1002/cplu.201500220. Epub 2015 Jul 3.

Authors

Zhiwei Chen¹, Christopher J Jeffery², Mahbod Morshedi², Graeme J Moxey², Adam Barlow², Xinwei Yang², Bandar A Babgi^{2

3}, Gulliver T Dalton², Michael D Randles², Matthew K Smith², Chi Zhang¹, Marek Samoc^{4

5}, Marie P Cifuentes^{1

2}, Mark G Humphrey^{1

2}

Affiliations

¹ School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, Jiangsu Province (P. R. China).
² Research School of Chemistry, Australian National University, Canberra, ACT 2601 (Australia).
³ Permanent address: Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia).
⁴ Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601 (Australia).
⁵ Present address: Advanced Materials Engineering and Modeling Group, Faculty of Chemistry, Wroclaw University of Technology, Wroclaw 50-370 (Poland).

PMID: 31973299
DOI: 10.1002/cplu.201500220

Abstract

The syntheses of trans-[Ru(C≡CC₆ H₄ -4-CHO)(C≡CC₆ H₄ -4-R)(dppe)₂ ] (R=H (9 a), NO₂ (9 b), CHO (9 c), C≡CC₆ H₃ -3,5-Et₂ (9 d), (E)-CHCHC₆ H₄ -4-tBu (9 e); dppe=1,2-bis(diphenylphosphino)ethane), trans-[Ru(C≡CC₆ H₄ -4-R)Cl(dppe)₂ ] (R=C≡CC₆ H₃ -3,5-Et₂ (11 a), (E)-CHCHC₆ H₄ -4-tBu (11 b), (E)-CHCHC₆ H₄ -4-NO₂ (11 c)), 1,2,4,5-{trans-[(dppe)₂ (RC₆ H₄ C≡C)Ru{C≡CC₆ H₄ -4-(E)-CHCH}]}₄ C₆ H₂ (R=H (14 a), C≡CC₆ H₃ -3,5-Et₂ (14 b), (E)-CHCHC₆ H₄ -4-tBu (14 c)), 1-I-3,5-{trans-[(L₂ )₂ (R)Ru{C≡CC₆ H₄ -4-(E)-CHCH}]}₂ C₆ H₃ (L₂ =1,1-bis(diphenylphosphino)methane (dppm)), R=Cl (15 a); L₂ =dppe, R=C≡CPh (15 b), R=C≡CC₆ H₄ -4-NO₂ (15 c)), 1-Me₃ SiC≡C-3,5-{trans-[(L₂ )₂ (R)Ru{C≡CC₆ H₄ -4-(E)-CHCH}]}₂ C₆ H₃ (L₂ =dppm, R=Cl (16 a); L₂ =dppe, R=C≡CPh (16 b)), 1-HC≡C-3,5-{trans-[(dppe)₂ (R)Ru{C≡CC₆ H₄ -4-(E)-CHCH}]}₂ C₆ H₃ (R=Cl (17 a), R=C≡CPh (17 b)), and 1,3,5-{trans-[(dppe)₂ (3,5-R₂ -C₆ H₃ C≡C)Ru{C≡CC₆ H₄ -4-(E)-CHCH}]}₃ C₆ H₃ (R=(E)-CHCHC₆ H₄ -4-C≡C-trans-[Ru(C≡CPh)(dppe)₂ ] (18)) are reported together with those of the precursor alkynes 1-RC≡C-3,5-Et₂ C₆ H₃ (R=SiMe₃ (2), H (3), C₆ H₄ -4-C≡CSiMe₃ (5), C₆ H₄ -4-C≡CH (6)). The identities of 9 c, 9 d, 9 e, 11 a, and trans-[Ru{C≡CC₆ H₄ -4-(E)-CHCHC₆ H₄ -4-tBu}₂ (dppe)₂ ] (12 and 12') were confirmed by single-crystal X-ray diffraction studies. The electrochemical properties of 9 a-e, 11 a-b, 14 a-c, 15 a-c, 16 b, 17 a, 17 b, and 18 were assessed by cyclic voltammetry; the studies reveal that potentials for the fully/quasi-reversible metal-centered oxidation processes decrease upon introduction of solubilizing alkyl substituents and increase upon increasing acceptor substituent strength; other structural variations have little impact. UV/Vis-NIR spectroscopic studies on these complexes reveal lowest-energy metal-ligand charge transfer (MLCT) bands that redshift upon increasing the acceptor substituent strength, blueshift on alkyl incorporation, and gain in intensity on progression from linear to star complexes. Low-temperature UV/Vis-NIR spectroelectrochemical studies of 14 a-c show the appearance of an intense low-energy band at 7400-7900 cm^-1 that is redshifted upon π-system lengthening and alkyl substituent incorporation. The cubic nonlinear optical properties of 9 d, 9 e, 14 a-c, 15 a-c, 16 b, 17 a, b, and 18 were assayed by femtosecond Z-scan studies at benchmark wavelengths (750 and 800 nm) in the near-IR region, with nonlinearity increasing upon nitro incorporation; the values for the E-ene-linked dendrimers in these studies are much larger than yne-linked analogues. Compounds 9 d, 9 e, 14 a-c, and 18 were further examined by broad-spectral-range femtosecond Z-scan studies; the cruciform complexes have appreciable multiphoton absorption cross-sections, with maximal values close to two and three times the wavelength of the linear optical absorption maxima.

Keywords: electrochemistry; nonlinear optics; redox chemistry; ruthenium; transition metals.

Abstract

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