1,556 research outputs found
Dynamic Permutational Isomerism in a closo-Cluster
Permutational isomers of trigonal bipyramidal [W2RhIr2(CO)9(η(5)-C5H5)2(η(5)-C5HMe4)] result from competitive capping of either a W2Ir or a WIr2 face of the tetrahedral cluster [W2Ir2(CO)10(η(5)-C5 H5)2] from its reaction with [Rh(CO)2(η(5)-C5HMe4)]. The permutational isomers slowly interconvert in solution by a cluster metal vertex exchange that is proposed to proceed by Rh-Ir and Rh-W bond cleavage and reformation, and via the intermediacy of an edge-bridged tetrahedral transition state. The permutational isomers display differing chemical and physical properties: replacement of CO by PPh3 occurs at one permutational isomer only, while the isomers display distinct optical power limiting behavior.We thank the Australian Research Council (Discovery Grant to
M.G.H. and M.P.C., ARC Australian Research Fellowship to
M.P.C.) for financial support. J.F. was the recipient of a China
Scholarship Council ANU Postgraduate Scholarship
Optical limiting properties of (reduced) graphene oxide covalently functionalized by coordination complexes
The nonlinear optical (NLO) and optical limiting (OL) properties of graphene oxide (GO), reduced graphene oxide (RGO), and particularly GO/RGO coordination complex hybrids are reviewed. A brief introduction to mechanisms of OL and a summary of the key measurement techniques for determining
NLO/OL merit is provided. A summary of synthetic procedures to GO/RGO coordination complex hybrids
is included.We thank the Australian Research Council (ARC) for financial
support. D.M.A.S.D. was the recipient of an Australian Postgraduate
Award
Exceptionally large two- and three-photon absorption cross-sections by OPV organometalation
Oligo(p-phenylenevinylene)s (OPVs) containing up to 8 PV units and end-functionalized by ruthenium alkynyl groups have been prepared and their nonlinear absorption properties assessed using the Z-scan technique and employing low repetition rate femtosecond pulses. Exceptionally large two-photon absorption (ca. 12â500 GM at 725 nm) and three-photon absorption cross sections (ca. 1.6 Ă 10â»â·â¶ cmâ¶sÂČ at 1100 nm) are found for the 8PV-containing example, highlighting the potential of an âorganometalationâ approach to NLO-efficient organic materialsWe thank the Australian Research Council (ARC), the National
Natural Science Foundation of China (51432006), the Chinese
Government Ministry of Education, the Chinese Government State
Administration of Foreign Experts Affairs (111 Project: B13025), and
the National Science Centre of Poland (grant 2013/10/A/ST4/00114)
for financial support. M. P. C. thanks the ARC for an Australian
Research Fellowship and C. Q. thanks CONICYT (Chile) for a Chile
PhD Scholarship Abroad
Covalent functionalization of reduced graphene oxide with porphyrin by means of diazonium chemistry for nonlinear optical performance
Reduced graphene oxide (RGO)-porphyrin (TPP) nanohybrids (RGO-TPP 1 and RGO-TPP 2) were prepared by two synthetic routes that involve functionalization of the RGO using diazonium salts. The microscopic structures, morphology, photophysical properties and nonlinear optical performance of the resultant RGO-TPP nanohybrids were investigated. The covalent bonding of the porphyrin-functionalized-RGO nanohybrid materials was confirmed by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin units to the surface of the RGO by diazotization significantly improves the solubility and ease of processing of these RGO-based nanohybrid materials. Ultraviolet/visible absorption and steady-state fluorescence studies indicate considerable Ï-Ï interactions and effective photo-induced electron and/or energy transfer between the porphyrin moieties and the extended Ï-system of RGO. The nonlinear optical properties of RGO-TPP 1 and RGO-TPP 2 were investigated by open-aperture Z-scan measurements at 532ânm with both 4âns and 21âps laser pulses, the results showing that the chemical nanohybrids exhibit improved nonlinear optical properties compared to those of the benchmark material C60, and the constituent RGO or porphyrins.Financial support from the National Natural Science Foundation of China (51432006, 50925207, 51172100), the Ministry of Science and Technology of China for the International Science Linkages Program (2011DFG52970), the Ministry of Education of China for the Changjiang Innovation Research Team (IRT14R23), the Ministry of Education and the State Administration of Foreign Experts Affairs for the 111 Project (B13025), and 100 Talents Program of CAS are gratefully acknowledged. M.G.H., C.Z. and M.P.C. thank the Australian Research Council (ARC) for support
Syntheses and Optical Properties of Azo-Functionalized Ruthenium Alkynyl Complexes
We thank the Australian Research Council (ARC), the National
Natural Science Foundation of China (51432006), and the Chinese
Government Ministry of Education and State Administration
of Foreign Experts Affairs (111 Project: B13025) for financial support.
M.P.C. thanks the ARC for an Australian Research Fellowship
Nonlinear optical properties of meso-Tetra(fluorenyl)porphyrins peripherally functionalized with one to four ruthenium alkynyl substituents
The synthesis of a series of four porphyrin derivatives based on a meso-tetrafluorenylporphyrin core functionalized with one to four trans-chlorobis(dppe)ruthenium alkynyl units (dppe = 1,2-bis(diphenylphosphino)ethane) at the periphery, together with cyclic voltammetry (CV) and UVâVis absorption and emission spectroscopy studies, are reported. In these multipolar assemblies, the organoruthenium endgroups are potential electron-donors and the central porphyrin core is a potential electron-acceptor. The third-order nonlinear optical (NLO) responses have been assessed by Z-scan, revealing that these extended Ï-networks incorporating polarizable organometallic units behave as nonlinear absorbers in the near-IR range. The role of the peripheral transition metal centers on the third-order NLO properties is discussed
Synthesis, Optical, Electrochemical, and Theoretical Studies of Dipolar Ruthenium Alkynyl Complexes with Oligo(phenylenevinylene) Bridges
We thank the Australian Research Council (ARC), the National Natural Science Foundation of China (51432006), the Chinese Government Ministry of Education, and the Chinese Government State Administration of Foreign Experts Affairs (111 Project: B13025). M.P.C. thanks the ARC for an Australian Research Fellowship and C.Q. thanks CONICYT (Chile) for a Chile PhD Scholarship Abroad
Mixed-metal cluster chemistry. 39. Syntheses and X-ray structures of Mo 3 Ir 3 (Ό 4 -η 2 -CO)(Ό 3 -CO)(CO) 10 (η 5 -C 5 H 5 ) 3 and Mo 3 RhIr 3 (Ό-CO) 4 (CO) 7 (η 5 -C 5 H 5 ) 3 (η 5 -C 5 Me 5 )
We thank the Australian Research Council (ARC) for support ofthis work. J.F. was the recipient of a China Scholarship Council ANUPostgraduate Scholarship and M.D.R. was the recipient of anAustralian Postgraduate Awar
Hybrids of gold nanoparticles and oligo(p-phenyleneethynylene)s end-functionalized with alkynylruthenium groups: Outstanding two-photon absorption in the second biological window
Oligo(p-phenyleneethynylene)s (OPEs) end-capped with (alkynyl)bis(diphosphine)ruthenium and thiol/thiolate groups stabilize ca. 2 nm diameter gold nanoparticles (AuNPs). The morphology, elemental composition and stability of the resultant organometallic OPE/AuNP hybrid materials have been defined using a combination of molecular- and nano-material chacterization techniques. The hybrids display long-term stability in solution (more than a month), good solubility in organic solvents, reversible ruthenium-centered oxidation, and transparency beyond 800 nm, and possess very strong nonlinear absorption activity at the first biological window, and unprecedented two-photon absorption activity in the second biological window (Ï2 up to 38,000 GM at 1,050 nm).We thank the Australian Research Council (DP170100411: M. G. H. and M. S.) and the National Science Centre (NCN) Poland (UMO-2016/22/M/ST4/00275: J. K. Z. and M. S.) for support of this work. C. Q. thanks Becas Chile (Agencia Nacional de InvestigaciĂłn y Desarrollo) for financial support in the form of a PhD scholarship (2015-72160061), J. P. L. M. thanks the Australian Government for an Australian Postgraduate Award, J. D. thanks the China Scholarship Council and the Australian National University for a CSC-ANU scholarship, and J. K. Z. thanks the Foundation for Polish Science (FNP) for support. The authors acknowledge the facilities, and the scientific and technical assistance, of the Australian Microscopy & Microanalysis Research Facility and the Centre of Advanced Microscopy at the Australian National University
Letter Ruling 99-1: Electronic Retailers
The synthesis and
characterization of a set of redox-active iron
and ruthenium alkynyl complexes of general formula [[M]ÂCl<sub>(1â<i>p</i>)</sub>{CîŒCC<sub>6</sub>H<sub>5â<i>m</i></sub>(CîŒCFlu)<sub><i>m</i></sub>}<sub>(1+<i>p</i>)</sub>]Â[PF<sub>6</sub>]<sub><i>n</i></sub> are
reported (<i>n</i> = 0â1; <i>m</i> = 1â2;
[M] = [FeÂ(η<sup>5</sup>-C<sub>5</sub>Me<sub>5</sub>)Â(Îș<sup>2</sup>-dppe)] and <i>p</i> = 1 or [M] = [<i>trans</i>-RuÂ(Îș<sup>2</sup>-dppe)<sub>2</sub>] and <i>p</i> = 0â1). The linear and third-order nonlinear optical properties
of these new organometallic complexes featuring phenylalkynyl ligands
functionalized by 2-fluorenyl (Flu) groups were studied in their stable
redox states. Their first electronic transitions are assigned with
the help of DFT calculations. We show here that these compounds possess
significant third-order NLO responses in the near-IR range for molecules
of their size. In particular, the remarkably large 2PA activities
of the new RuÂ(II) compounds in the 600â800 nm range (<i>Z</i>-scan) make them attractive nonlinear chromophores. Structureâproperty
studies emphasize the importance of para- versus meta-connection of
the 2-fluorenylethynyl units on the phenylalkynyl core and reveal
that upon progressing from mono- to bis-alkynyl complexes a further
increase of the 2PA cross section can be obtained while maintaining
linear transparency in the visible range
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