Search

International audience; 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 UV–Vis 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 π-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.

Ruthenium(II) arene complexes of the general formula [RuCl(&eta, 6-p-cymene)(diamine)]PF6 (diamine = 1,2-diaminobenzene (1), 2,3-diaminonaphthalene (2), 9,10-diaminophenanthrene (3), 2,3-diaminophenazine (4), and 1,2-diaminoanthraquinone (5) were synthesized. Chloro/aqua exchange was evaluated experimentally for complexes 1 and 2. The exchange process was investigated theoretically for all complexes, revealing relatively fast exchange with no significant influence from the polycyclic aromatic diamines. The calf thymus DNA (CT-DNA) binding of the complexes increased dramatically upon extending the aromatic component of the diamines, as evaluated by changes in absorption spectra upon titration with different concentrations of CT-DNA. An intercalation binding mode was established for the complexes using the increase in the relative viscosity of the CT-DNA following addition of complexes 1 and 2. Theoretical studies showed strong preference for replacement of water by guanine for all the complexes, and relatively strong Ru&ndash, Nguanine bonds. The plane of the aromatic systems can assume angles that support non-classical interactions with the DNA and covalent binding, leading to higher binding affinities. The ruthenium arenes illustrated in this study have promising anticancer activities, with the half maximal inhibitory concentration (IC50) values comparable to or better than cisplatin against three cell lines.

The copper(I) coordination compounds of general formula [CuBr(PPh3)(N^N)] (N^N = 2,2′-bipyridine (1), 1,10-phenanthroline (2), 4,4′-dimethyl-2,2′-bipyridine (3), 4,4′-dimethoxy-2,2′-bipyridine (4), 3-(2-pyridyl)-4,5-diphenyl-1,2,4-triazine (5), 4,7-diphenyl-1,10-phenanthroline (6), 5-nitro-1,10-phenanthroline (7), dipyrido[3,2-a:2′,3′-c]phenazine(8)) have been synthesized and characterized by elemental analysis, 31P NMR spectroscopy and mass spectrometry. The structure of 5 and 7 were confirmed by X-ray crystallography. 5 is the second example to be reported with an unusual 4 N-triazine-ligated coordination mode of the 3-(2-pyridyl)-4,5-diphenyl-1,2,4-triazine. Calculated energies of the two possible bidentate modes of the ligand (2 N- and 4 N-triazine) at the copper center showed no significant difference, consistent with the absence of the steric hindrance at the metal center. Preliminary biological studies were conducted, highlighting the effect of the diimine ligands. 5 and 8 exhibited good cytotoxicity against prostate (PC-3), leukemia (MOLT-4) and breast (MCF-7) cancer cell lines, consistent with the presence of nitrogen heteroatoms and extended delocalized systems correlating with strong cytotoxic performance. Binding affinity studies against ct-DNA and docking studies with B-DNA and MDM2 protein highlighted the strong π interactions of 5 and 8, with the planarity of the diimine ligand of the latter contributing to its better binding and cytotoxicity. The present results afford structural design requirements for new copper(I) coordination compounds with enhanced biological/physiochemical properties.

International audience; Four new mononuclear alkynyl complexes each featuring a terminal 2-fluorenyl group, namely Fe(η5-C5Me5)(CO)2[C≡C(2-C21H25)] (2), Ru(κ2-dppe)2Cl[C≡C(2-C21H25)] (3), Ru(κ2-dppe)2[C≡C(4-C6H4NO2)][C≡C(2-C21H25)] (4), and [Fe(η5-C5Me5)(κ2-dppe)_C≡C(C5H4N)-CH2(2-C13H9)_][PF6] (5[PF6]), have been synthesized and characterized, and their redox, absorption, and emission properties have been studied. For the two ruthenium derivatives 3 and 4, these studies are complemented by spectroelectrochemical investigations, Z-scan measurements, and DFT calculations. Fluorimetric studies reveal that these compounds are poorly or not luminescent, and, when luminescent, that the detected weak luminescence most likely originates from a higher lying ligand-centred (LC) excited state presumably located on fluorene. Finally, the third-order nonlinear optical (NLO) properties of 3 and 4 are reported. It is shown that the bis-alkynyl complex 4 is significantly more active than 3 and that both compounds exhibit two-photon absorption (TPA) around 860–1050 nm, with TPA cross-sections above 350 GM. In addition, it is shown that both species should give rise to a marked switching of their cubic NLO properties in this spectral range upon oxidation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Tetrahedral Mo2Ir2(μ3-CO)(μ-CO)5(CO)4(η5-C5H5)2 (1) reacted with P(C6H4Me-4)3, P(C6H2Me2-3,5-OMe-4)3, and AsPh3 to afford the substitution products Mo2Ir2(μ-CO)3(CO)6(L)(η5-C5H5)2 [L = P(C6H4Me-4)3 (3), P(C6H2Me2-3,5-OMe-4)3 (4), AsPh3 (5)] in fair to good yields, while reaction of 1 with HC≡CSiPri3 proceeded by insertion into the Mo–Mo bond to give the pseudo-octahedral Mo2Ir2(μ4-η2-HC2SiPri3)(μ-CO)4(CO)4(η5-C5H5)2 (6) in fair yield. While MoIr3(μ-CO)3(CO)7(η5-C5H5) reacted with HC≡CSiMe3 to give a complex mixture of thus-far-uncharacterized products, its phosphine substitution product MoIr3(μ-CO)3(CO)5(PPh3)2(η5-C5H5) reacted with the same alkyne via insertion into a Mo–Ir bond to afford the pseudo-octahedral MoIr3(μ4-η2-HC2SiMe3)(μ-CO)3(CO)4(PPh3)2(η5-C5H5) (8) in good yield. Clusters 4, 5 (two isomers), 6 and 8 have been characterized by single-crystal X-ray diffraction studies. Cyclic voltammetric studies of Mo2Ir2(μ-CO)3(CO)6(PPh3)(η5-C5H5)2 (2), 3–6 and 8 confirmed the tuning of redox potentials upon phosphines/arsine introduction and alkyne modification. IR spectroelectrochemical studies of 2, 6, and 8 suggest decreasing proclivity for bridging carbonyl ligands following oxidation. Variable temperature 31P NMR studies of 3 and 4 revealed interconverting isomers in solution, the structures of which are assigned as analogues of the X-ray diffraction-confirmed isomers of 5. Studies of 2–5 using ns pulses and the open-aperture Z-scan technique revealed that all are optical limiters at wavelengths in the visible region.

The use of carbon-dot-based dual-emission fluorescent nanohybrids (DEFNs) as versatile nanothermometry devices for spatially resolved temperature measurements in living cells is demonstrated. The carbon dots (CDs) are prepared in the organic phase and display tunable photoluminescence (PL) across a wide visible range by adjusting the excitation wavelengths and extend of N-doping. DEFNs are formed in a straightforward fashion from CDs (emitting blue PL) and gold nanoclusters (AuNCs, emitting red PL). The DEFNs display ideal single-excitation, dual-emission with two well-resolved, intensity-comparable fluorescence peaks, and function in optical thermometry with high reliability and accuracy by exploiting the temperature sensitivity of their fluorescence intensity ratio (blue/red). Furthermore, the DEFNs have been introduced into cells, exhibiting good biocompatibility, and have facilitated physiological temperature measurements in the range of 25-45 °C; the DEFNs can therefore function as "non-contact" tools for the accurate measurement of temperature and its gradient inside a living cell.

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.

Reduced graphene oxide-tin porphyrin (RGO-SnTPP) nanohybrids with good dispersibility have been prepared by two covalent functionalization approaches. The microscopic structure and morphology of the RGO-SnTPP nanohybrids were characterized by various spectroscopic techniques including Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy. Ground-state absorption and steady-state fluorescence studies indicate considerable π–π interactions and effective photo-induced electron and/or energy transfer from the porphyrin moieties to the RGO. Their nonlinear optical properties were investigated using the Z-scan technique at 532 nm with both picosecond and nanosecond laser pulses. The RGO-SnTPP hybrids were found to exhibit large nonlinear optical responses due to a combination of mechanisms, while significant differences in their nonlinear optical responses were observed, highlighting the influence on photophysical properties of the degree of functionalization and the synthetic approach employed.

A facile and scalable approach to synthesize trinickel monophosphide (Ni3P) porous hollow nanospheres (PHNs) has been developed, the resultant Ni3P PHNs exhibiting excellent catalytic activity in the hydrogen evolution reaction (HER). The formation of the Ni3P PHNs correlates with phase separation during the thermal annealing of amorphous nickel–phosphorus nanospheres that affords crystalline Ni–Ni3P nanoparticles, and the subsequent selective removal of nickel. The overpotential required for the current density of 20 mA cm−2 is as small as 99 mV in acidic solution. The performance compares favorably with that of other metal phosphides, and is superior to that of transition metal dichalcogenides, carbides, borides, and nitrides. The faradaic efficiency of the Ni3P PHNs is 96%, and the Ni3P PHNs are stable during the long-term electrolysis of water. Density functional theory calculations suggest that a Ni–Ni bridge site and the sites on the top of the P atoms are the active sites during the HER. The scalable production, low cost, excellent catalytic activity, and long-term stability suggest promising application potential for Ni3P PHNs.

Carbazole-carborane linear dyads and di(carbazole)-carborane V-shaped dyads with phenyleneethynylene-based bridges have been synthesized. The V-shaped dyads display the expected red-shifts in the location of their UV-Vis absorption maxima on bridge-lengthening, but show unusual blue-shifts in charge-transfer (CT) emission on the same π-system lengthening. These blue-shifts can be attributed to the 2n + 3 electron count within the carborane cluster in the excited state. The linear dyads luminesce via a combination of local excited (LE) and CT emission, with a red-shift in LE emission and a blue-shift in CT emission accompanying π-bridge elongation. A quantum efficiency as high as 86% in the solution state is achieved from the hybrid LE/CT emission. Time-dependent density functional theory (TD-DFT) calculations at the excited state of these compounds have clarified the photoluminescence blue-shift and suggested a typical cluster C-C bond elongation in the V-shaped dyads. Calculations on the elongated linear dyads have suggested that the electron density is localized at the phenyleneethynylene-containing bridge.

An ammonium-crown ether host-guest supramolecular cation-templated synthetic methodology has been developed to construct a structurally unprecedented heterobicluster-metal coordination polymer (HCM-CP 1) based on tetranuclear clusters [WS4Cu3](+) with different connection environments, pentanuclear clusters [WS4Cu4](2+), and Cu(+) building metal ions. HCM-CP 1 exhibits enhanced NLO properties, which may be ascribed to the incorporation of diverse building cluster components.

Multi-walled carbon nanotube (MWCNT)/TiO2 nanocomposites have been prepared by a hydrothermal method and characterized by Fourier-transform infrared, Raman, and X-ray photoelectron spectroscopies, X-ray powder diffraction, and transmission electron microscopy. Their viability as nonlinear optical (NLO) materials has been examined using the Z-scan technique at 532 nm with both nanosecond and picosecond laser pulses, the NLO and optical limiting (OL) performance being found to be dependent on the TiO2 content. At the wavelength used, an enhanced OL response was observed for the M1.00 nanocomposite and ascribed to a combination of mechanisms.

Axially coordinated metal-porphyrin-functionalized multi-walled carbon nanotube (MWCNT) nanohybrids were prepared via two different synthetic approaches (a one-pot 1,3-dipolar cycloaddition reaction and a stepwise approach that involved 1,3-dipolar cycloaddition followed by nucleophilic substitution), and characterized through spectroscopic techniques. Attachment of the tin porphyrins to the surface of the MWCNTs significantly improves their solubility and ease of processing. These axially coordinated (5,10,15,20-tetraphenylporphyrinato)tin(IV) (SnTPP)-MWCNTs exhibit significant fluorescence quenching. The third-order nonlinear optical properties of the resultant nanohybrids were studied by using the Z-scan technique at 532 nm with both nanosecond and picosecond laser pulses. The results show that the nanohybrids exhibit significant reverse saturable absorption or saturable absorption when nanosecond or picosecond pulses, respectively, are employed. Improvement in the nanosecond regime nonlinear absorption is observed on proceeding to the nanohybrids and is ascribed to a combination of the outstanding properties of MWCNTs and the chemically attached metal-porphyrins.

The systematic study on the reaction variables affecting single cyanide-bridged Mo(W)/S/Cu cluster-based coordination polymers (CPs) is firstly demonstrated. Five anionic single cyanide-bridged Mo(W)/S/Cu cluster-based CPs {[Pr4N][WS4Cu3(CN)2]}n (1), {[Pr4N][WS4Cu4(CN)3]}n (2), {[Pr4N][WOS3Cu3(CN)2]}n (3), {[Bu4N][WOS3Cu3(CN)2]}n (4) and {[Bu4N][MoOS3Cu3(CN)2]}n (5) were prepared by varying the molar ratios of the starting materials, and the specific cations, cluster building blocks and central metal atoms in the cluster building blocks. 1 possesses an anionic 3D diamondoid framework constructed from 4-connected T-shaped clusters [WS4Cu3]+ and single CN− bridges. 2 is fabricated from 6-connected planar ‘open’ clusters [WS4Cu4]2+ and single CN− bridges, forming an anionic 3D architecture with an “ACS” topology. 3 and 4 exhibit novel anionic 2-D double-layer networks, both constructed from nest-shaped clusters [WOS3Cu3]+ linked by single CN− bridges, but containing the different cations [Pr4N]+ and [Bu4N]+, respectively. 5 is constructed from nest-shaped clusters [MoOS3Cu3]+ and single CN− bridges, with an anionic 3D diamondoid framework. The anionic frameworks of 1-5, all sustained by single CN− bridges, are non-interpenetrating and exhibit huge potential void volumes. Employing differing molar ratios of the reactants and varying the cluster building blocks resulted in differing single cyanide-bridged Mo(W)/S/Cu cluster-based CPs, while replacing the cation ([Pr4N]+ vs. [Bu4N]+) was found to have negligible impact on the nature of the architecture. Unexpectedly, replacement of the central metal atom (W vs. Mo) in the cluster building blocks had a pronounced effect on the framework. Furthermore, the photocatalytic activities of heterothiometallic cluster-based CPs were firstly explored by monitoring the photodegradation of methylene blue (MB) under visible light irradiation, which reveals that 2 exhibits effective photocatalytic properties.

Three new alkali-metal gallium phosphates NaGa3(PO4)2F4(H2O)2 (1), KGa2P2O7(OH)3(H2O) (2), and RbGa2P2O7(OH)3(H2O) (3) were obtained using hydrothermal methods. Compound 1 crystallizes in the chiral space group P43212. The structure of 1 features a three-dimensional (3D) framework composed of 2D layers of corner-sharing GaO4F2 and GaO2F4 octahedra that are further bridged by PO4 tetrahedra with Na+ cations residing in the oxyfluorinated gallolayers. Compounds 2 and 3 are isostructural, both crystallizing in the centrosymmetric space group P21/c; their structures consist of novel 3D gallophosphate frameworks constructed from Ga4O20 tetramers interconnected by PO4 units with 8-membered ring channels along the b-axis, in which K+/Rb+ cations are located. The diffuse reflectance spectra show that the ultraviolet (UV) cut-off edges are about 292 ​nm (4.25 ​eV), 275 ​nm (4.51 ​eV) and 306 ​nm (4.05 ​eV) for 1–3, respectively. Luminescent studies suggest that 1–3 emit blue light under the excitation of near-ultraviolet light.

Oligo(2,5-thienylenevinylene)s (OTVs) end-functionalized with a ligated ruthenium alkynyl unit as a donor and a nitro as acceptor, namely trans-[Ru{C C-2,5-C4H2S(NO2)}Cl(dppe)2] (Ru1T), trans-[Ru{C C-2,5-C4H2S-(E)-CH CH-2,5-C4H2S(NO2)}Cl(dppe)2] (Ru2T), and trans-[Ru{C C-2,5-C4H2S-(E)-CH CH-2,5-C4H2S-(E)-CH CH-2,5-C4H2S(NO2)}Cl(dppe)2] (Ru3T), have been synthesized, their electrochemical properties have been assessed by cyclic voltammetry (CV), their linear optical and quadratic nonlinear optical (NLO) properties have been assayed by UV–vis–NIR spectroscopy and hyper-Rayleigh scattering studies at 1300 nm, respectively, and their linear optical properties in the formally RuIII state have been examined by UV–vis–NIR spectroelectrochemistry. The data for Ru1T-Ru3T have been compared to those of the oligo(p-phenylenevinylene) (OPV) analogues trans-[Ru(C C-1,4-C6H4NO2)Cl(dppe)2] (Ru1P), trans-[Ru{C C-1,4-C6H4-(E)-CH CH-1,4-C6H4NO2}Cl(dppe)2] (Ru2P), and trans-[Ru{C C-1,4-C6H4-(E)-CH CH-1,4-C6H4-(E)-CH CH-1,4-C6H4NO2}Cl(dppe)2] (Ru3P). The RuII/III oxidation potentials decrease on proceeding from Ru1T to Ru3T, while the wavelength of the UV–vis λmax band increases on proceeding from Ru1T to Ru2T, but thereafter decreases on further progression to Ru3T, similar trends to those seen proceeding from Ru1P to Ru3P. The quadratic nonlinearity β1300 increases on OTV lengthening from Ru1T through Ru2T to Ru3T; the data are significantly larger than those of the Ru1P–Ru3P analogues which peak at Ru2P. The formally RuIII complexes exhibit low-energy bands that red-shift significantly on proceeding from Ru1T to Ru3T. Computational studies employing time-dependent density functional theory were undertaken on model complexes to rationalize the optical observations and explore the impact of further OTV bridge lengthening. Computational studies on model complexes Ru1T′-Ru6T′ are consistent with decreasing contributions of the electron donor (ligated Ru) and acceptor (NO2) groups to the HOMO and LUMO, respectively, upon π-bridge lengthening. βtot values increase on progression from Ru1T′ to Ru3T′, but thereafter further bridge lengthening affords little further increase in βtot, consistent with a saturation in quadratic NLO response.

1-Nitronaphthalenyl-4-alkynyl and 9-nitroanthracenyl-10-alkynyl complexes [M](C[triple bond, length as m-dash]C-4-C10H6-1-NO2) ([M] = trans-[RuCl(dppe)2] (6b), trans-[RuCl(dppm)2] (7b), Ru(PPh3)2(η5-C5H5) (8b), Ni(PPh3)(η5-C5H5) (9b), Au(PPh3) (10b)) and [M](C[triple bond, length as m-dash]C-10-C14H8-9-NO2) ([M] = trans-[RuCl(dppe)2] (6c), trans-[RuCl(dppm)2] (7c), Ru(PPh3)2(η5-C5H5) (8c), Ni(PPh3)(η5-C5H5) (9c), Au(PPh3) (10c)) were synthesized and their identities were confirmed by single-crystal X-ray diffraction studies. Electrochemical studies and a comparison to the 1-nitrophenyl-4-alkynyl analogues [M](C[triple bond, length as m-dash]C-4-C6H4-1-NO2) ([M] = trans-[RuCl(dppe)2] (6a), trans-[RuCl(dppm)2] (7a), Ru(PPh3)2(η5-C5H5) (8a), Ni(PPh3)(η5-C5H5) (9a), Au(PPh3) (10a)) reveal a decrease in oxidation potential for ruthenium and nickel complexes on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. HOMO → LUMO transitions characteristic of MC[triple bond, length as m-dash]C-1-C6H4 to 4-C6H4-1-NO2 charge transfer red-shift and gain in intensity on proceeding to the ruthenium complexes; the low-energy transitions have increasing ILCT character on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. Spectroelectrochemical studies of the Ru-containing complexes reveal the appearance of low-energy bands corresponding to chloro-to-RuIII charge transfer that red-shift on proceeding from the phenyl- to naphthalenyl- and then anthracenyl-containing bridge. Second-order nonlinear optical (NLO) studies at 1064 nm employing ns pulses and the hyper-Rayleigh scattering technique reveal an increase in quadratic optical nonlinearity upon introduction of metal to the precursor alkyne to afford alkynyl complexes and on proceeding from ligated-gold to -nickel and then to -ruthenium for a fixed alkynyl ligand. Quadratic NLO data of the gold complexes optically transparent at the second-harmonic wavelength reveal an increase in βHRS on proceeding from the phenyl- to the naphthalenyl-containing complex. Broad spectral range third-order nonlinear optical studies employing fs pulses and the Z-scan technique reveal an increase in two-photon absorption cross-section on replacing ligated-gold by -nickel and then -ruthenium for a fixed alkynyl ligand. Computational studies undertaken using time-dependent density functional theory have been employed to assign the nature of the key optical transitions and suggest that the significant optical nonlinearities observed for the ruthenium-containing complexes correlate with the low-energy formally Ru → NO2 band which possesses strong MLCT character, while the more moderate nonlinearities of the gold complexes correlate with a band higher in energy that is primarily ILCT in character.

The syntheses of oligo(p-phenylene ethynylene)s (OPEs) end-functionalized by a nitro acceptor group and with a ligated ruthenium unit at varying locations in the OPE chain, namely, trans-[Ru{(C≡C-1,4-C6 H4 )n NO2 }(C≡CR)(dppe)2 ] (dppe=1,2-bis(diphenylphosphino)ethane; n=1, R=1,4-C6 H4 C≡C-1,4-C6 H4 C≡CPh, 1,4-C6 H4 NEt2 ; n=2, R=Ph, 1,4-C6 H4 C≡CPh, 1,4-C6 H4 C≡C-1,4-C6 H4 C≡CPh, 1,4-C6 H4 NO2 , 1,4-C6 H4 NEt2 ; n=3, R=Ph, 1,4-C6 H4 C≡CPh), are reported. Their electrochemical properties were assessed by cyclic voltammetry, their linear optical properties and quadratic and cubic nonlinear optical properties were assayed by UV/Vis/NIR spectroscopy, hyper-Rayleigh scattering studies employing nanosecond pulses at 1064 nm, and broad spectral range Z-scan studies employing femtosecond pulses, respectively, and their linear optical properties and vibrational spectroscopic behavior in the formally RuIII state was examined by UV/Vis/NIR and IR spectroelectrochemistry, respectively. The potentials of the metal-localized oxidation processes are sensitive to alkynyl-ligand modification, but this effect is attenuated on π-bridge lengthening. Computational studies employing time-dependent density functional theory were undertaken on model complexes, with a 2D scan revealing a soft potential-energy surface for intra-alkynyl-ligand aryl-ring rotation; this is consistent with the experimentally observed blueshift in optical absorption maxima. Quadratic optical nonlinearities are significant and cubic NLO coefficients for these small complexes are small. The optimum length of the alkynyl ligands and the ideal metal location in the OPE to maximize the key coefficients have been defined.

International audience; This contribution reports the synthesis of C87H60N6O3 (3-NPh2), the tristyryl analogue of the triphenylisocyanurate C81H54N6O3 (2-NPh2) which was previously demonstrated to be an active two-photon absorber. Contrary to expectation, planarization and extension of the central -system does not lead to a marked improvement of the two-photon absorption cross-section.

The complex with the formula [Ru(bpy)2(2,3-diaminonaphthalene)][PF6] (5) was synthesized and characterized by 1H NMR spectroscopy, mass spectrometry and elemental analysis. A set of previously reported complexes with the formula [Ru(bpy)2(diamine)][PF6]{diamine = 1,2-diaminoethane (2), o-phenylenediamine (3), 1,2-diaminocyclohexane (4) } was synthesized and crystal structures were obtained for complexes 3 and 4. UV–vis absorption spectra of the complexes 2–5 were collected and compared to that of [Ru(bpy)3][PF6]2 (1), showing that the MLCT band is red-shifted upon introducing the diamine ligands in place of bipyridine. Emission spectra, excited-state lifetimes and emission quantum yields were collected at room temperature for the complexes 1–5, showing considerable changes in the photophysical characteristics upon the introductions of the diamine. The emission spectrum of 5 exhibits an intense emission in the far red-NIR region when excited at 510 nm. The cyclic voltammograms of the complexes 1–5 show one oxidation peak between 0.98 V and 1.15 V which is attributed to the Ru(II)/Ru(III) oxidation couple. Calculated HOMO and LUMO energy levels from both electrochemical data and theoretical calculations suggest a lower HOMO energy level for complex 1 than the diamino-containing complexes, presumably due to the stronger ligand field of the bipyridine. © 2018 Elsevier B.V.

The reaction of Ir(CO)2(η5-C5HMe4) with Mo2Ir2(μ-CO)3(CO)7(η5-C5H5)2 affords a complex mixture from which three structurally-characterized products were obtained following thin-layer chromatography. Mo3Ir3(μ3-O)(μ-CO)3(CO)8(η5-C5H5)3 (1) is Effective Atomic Number (EAN) Rule EAN-precise and possesses an edge-bridged trigonal bipyramidal core with the face-capping oxo ligand located in a Mo2Ir2 butterfly cleft in the structure. Mo4Ir4(μ-CO)4(CO)9(η5-C5H5)4 (2) possesses four electrons less than the Polyhedral Skeletal Electron Pair Theory (PSEPT)-expected count for a capped pentagonal bipyramidal cluster with the apical atoms within bonding distance. Mo3Ir5(μ-CO)3(Cl)(CO)6(η5-C5H5)3(η5-C5HMe4) (3) possesses a tetracapped tetrahedral core and has six electrons less than the PSEPT-predicted electron count. The core geometries exhibited by clusters 2 and 3 have previously only been observed for clusters including significant group 10 and group 11 metal content.

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 (2009DFA50620, 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 Jiangsu Innovation Research Team are gratefully acknowledged. M.G.H. and M.P.C. thank the Australian Research Council for support.

The synthesis of fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡CH)}3] (10), which bears pendant ethynyl groups, and its reaction with [RuCl(dppe)2]PF6 to afford the heterobimetallic complex fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CC6H4-4-C≡C-trans-[RuCl(dppe)2])}3] (11) is described. Complex 10 is available from the two-step formation of iodo-functionalized fac-tris[2-(4-iodophenyl)pyridine]iridium(III) (6), followed by ligand-centered palladium-catalyzed coupling and desilylation reactions. Structural studies of tetrakis[2-(4-iodophenyl)pyridine-N,C1′](μ-dichloro)diiridium 5, 6, fac-[Ir{N,C1′-(2,2′-NC5H4C6H3-5′-C≡C-1-C6H2-3,5-Et2-4-C≡CH)}3] (8), and 10 confirm ligand-centered derivatization of the tris(2-phenylpyridine)iridium unit. Electrochemical studies reveal two (5) or one (6–10) Ir-centered oxidations for which the potential is sensitive to functionalization at the phenylpyridine groups but relatively insensitive to more remote derivatization. Compound 11 undergoes sequential Ru-centered and Ir-centered oxidation, with the potential of the latter significantly more positive than that of Ir(N,C′-NC5H4-2-C6H4-2)3. Ligand-centered π–π* transitions characteristic of the Ir(N,C′-NC5H4-2-C6H4-2)3 unit red-shift and gain in intensity following the iodo and alkynyl incorporation. Spectroelectrochemical studies of 6, 7, 9, and 11 reveal the appearance in each case of new low-energy LMCT bands following formal IrIII/IV oxidation preceded, in the case of 11, by the appearance of a low-energy LMCT band associated with the formal RuII/III oxidation process. Emission maxima of 6–10 reveal a red-shift upon alkynyl group introduction and arylalkynyl π-system lengthening; this process is quenched upon incorporation of the ligated ruthenium moiety on proceeding to 11. Third-order nonlinear optical studies of 11 were undertaken at the benchmark wavelengths of 800 nm (fs pulses) and 532 nm (ns pulses), the results from the former suggesting a dominant contribution from two-photon absorption, and results from the latter being consistent with primarily excited-state absorption.

The syntheses of trans-[Ru(C≡CC6H4-4-CHO)(C≡CC6H4-4-R)(dppe)2] (R=H (9 a), NO2 (9 b), CHO (9 c), C≡CC6H3-3,5-Et2 (9 d), (E)-CHCHC6H4-4-tBu (9 e); dppe=1,2-bis(diphenylphosphino)ethane), trans-[Ru(C≡CC6H4-4-R)Cl(dppe)2] (R=C≡CC6H3-3,5-Et2 (11 a), (E)-CHCHC6H4-4-tBu (11 b), (E)-CHCHC6H4-4-NO2 (11 c)), 1,2,4,5-{trans-[(dppe)2(RC6H4C≡C)Ru{C≡CC6H4-4-(E)-CHCH}]}4C6H2 (R=H (14 a), C≡CC6H3-3,5-Et2 (14 b), (E)-CHCHC6H4-4-tBu (14 c)), 1-I-3,5-{trans-[(L2)2(R)Ru{C≡CC6H4-4-(E)-CHCH}]}2C6H3 (L2=1,1-bis(diphenylphosphino)methane (dppm)), R=Cl (15 a); L2=dppe, R=C≡CPh (15 b), R=C≡CC6H4-4-NO2 (15 c)), 1-Me3SiC≡C-3,5-{trans-[(L2)2(R)Ru{C≡CC6H4-4-(E)-CHCH}]}2C6H3 (L2=dppm, R=Cl (16 a); L2=dppe, R=C≡CPh (16 b)), 1-HC≡C-3,5-{trans-[(dppe)2(R)Ru{C≡CC6H4-4-(E)-CHCH}]}2C6H3 (R=Cl (17 a), R=C≡CPh (17 b)), and 1,3,5-{trans-[(dppe)2(3,5-R2-C6H3C≡C)Ru{C≡CC6H4-4-(E)-CHCH}]}3C6H3 (R=(E)-CHCHC6H4-4-C≡C-trans-[Ru(C≡CPh)(dppe)2] (18)) are reported together with those of the precursor alkynes 1-RC≡C-3,5-Et2C6H3 (R=SiMe3 (2), H (3), C6H4-4-C≡CSiMe3 (5), C6H4-4-C≡CH (6)). The identities of 9 c, 9 d, 9 e, 11 a, and trans-[Ru{C≡CC6H4-4-(E)-CHCHC6H4-4-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.

Reaction of Mo2Ir3(μ-CO)3(CO)6(η5-C5H5)2(η5-C5Me5) with Ir(CO)2(η5-C5Me4H) afforded the four-valence-electron-deficient butterfly cluster Ir4(CO)6(η5-C5Me4H)2; its stability has been rationalized with the aid of density functional theory calculations, which suggest that significant additional intracluster bonding alleviates the formal electron deficiency. Reaction of MoIr4(CO)10(η5-C5H5)(η5-C5Me5) with [N(PPh3)2][Ir(CO)4] afforded the capped octahedral cluster Ir7(μ3-CO)3(CO)12(η5-C5Me5), which possesses three semi-face-capping CO ligands. These outcomes demonstrate that heterometallic clusters may serve as a potential source of new homometallic clusters following appropriate M–M′ cleavage.

Three unusual three-dimensional (3D) tetrazine chromophore-based metal-organic frameworks (MOFs) {(Et4 N)[WS4 Cu3 (CN)2 (4,4'-pytz)0.5 ]}n (1), {[MoS4 Cu4 (CN)2 (4,4'-pytz)2 ]⋅CH2 Cl2 }n (2), and {[WS4 Cu3 (4,4'-pytz)3 ]⋅[N(CN)2 ]}n (3; 4,4'-pytz=3,6-bis(4-pyridyl)tetrazine) have been synthesized and characterized by using FTIR and UV/Vis spectroscopy, elemental analysis, powder X-ray diffraction, gel permeation chromatography, steady-state fluorescence, and thermogravimetric analysis; their identities were confirmed by single-crystal X-ray diffraction studies. MOF 1 possesses the first five-connected M/S/Cu (M=Mo, W) framework with an unusual 3D (4(4) ⋅6(6) ) topology constructed from T-shaped [WS4 Cu3 ](+) clusters as nodes and single CN(-) /4,4'-pytz bridges as linkers. MOF 2 features a novel 3D MOF structure with (4(20) ⋅6(8) ) topology, in which the bridging 4,4'-pytz ligands exhibit unique distorted arch structures. MOF 3 displays the first 3D MOF structure based on flywheel-shaped [WS4 Cu3 ](+) clusters with a non-interpenetrating honeycomb-like framework and a heavily distorted "ACS" topology. Steady-state fluorescence studies of 1-3 reveal significant fluorescence emissions. The nonlinear optical (NLO) properties of 1-3 were investigated by using a Z-scan technique with 5 ns pulses at λ=532 nm. The Z-scan experimental results show that the π-delocalizable tetrazine-based 4,4'-pytz ligands contribute to the strong third-order NLO properties exhibited by 1-3. Time-dependent density functional theory studies afforded insight into the electronic transitions and spectral characterization of these functionalized NLO molecular materials.

This work was supported by the National Natural Science Foundation of China (No. 50925207), the Natural Science Foundation of Jiangsu Province, China (BK20140157), Programme of Introducing Talents of Discipline to Universities (111 Project B13025), and the Fundamental Research Funds for the Central Universities (JUSRP11418).

Dedicated to Dr. Claude Lapinte on the occasion of his retirement, in memory of the good times spent together in France and Australia.; International audience; A nonametallic organometallic-coordination complex (4), assembled from redox-active ferrocenyl (Fc) and Ru(κ2-dppe)2 fragments (dppe = 1,2-bis(diphenylphosphino)ethane) as peripheral donor groups and a central Zn(II) tetraphenylporphyrin (ZnTPP) core, has been prepared and characterized. Complex 4 is obtained in one step from a pentametallic organometallic porphyrin precursor following substitution of the peripheral chloride ligands by ferrocenylalkynyl moieties (Ctriple bond; length of mdashCFc). The spectroelectrochemistry of 4, and that of previously reported porphyrins featuring related peripheral electron-rich d6-transition metal alkynyl units, has been investigated; the optical and redox properties of 4 are briefly discussed, and its potential, and that of a related pentanuclear tetraferrocenyl ZnTPP complex, to function as redox-switchable chromophores is examined. Preliminary studies of the cubic NLO properties of 4 have been undertaken by Z-scan studies at 560 nm and 630 nm, the results from which are also reported.

In this work, we develop a novel dual-emitting hollow TiO2 microsphere with high stability and attractive thermal sensitivity, which could work as nanosensor for accurately measuring temperature. This nanosensor is prepared through coating gold nanocluster (AuNCs) on the surface of carbon dots-doped hollow TiO2 microsphere. As-prepared nanosensor shows characteristic dual-emitting property of carbon dots (CDs, blue fluorescence) and AuNCs (red fluorescence) under a single excitation wavelength. Moreover, upon increasing the temperature, the intensity of red emission from the AuNCs continuously quenched, whereas that of blue emission from the CDs remained nearly constant. The different response results in a continuous fluorescence color change from red to purple that can be clearly observed by the naked eyes. Thus, as-prepared dual-emitting hollow TiO2 microsphere could be used as optical thermometry by taking the advantage of the temperature sensitivity of their fluorescence intensity ratio (red/blue) with high reliability and accuracy, which change considerably over the wide temperature range (20–80 °C) with small temperature resolution (∼0.5 °C). Additionally, this nanosensor is successfully applied in 10 mM buffered saline (PBS) solution with physiological temperature ranging from 20 to 45 °C, which suggests as-prepared dual-emitting microspheres have promising applications in vivo temperature sensing.

A new Zn(ii) porphyrin-cored ruthenium alkynyl dendrimer (2) containing twelve Ru(κ(2)-dppe)2 bis-alkynyl fragments has been prepared in two steps from 5,10,15,20-tetra(4-ethynylphenyl)porphyrinatozinc(ii) and shown to be highly active for third-harmonic generation (THG) at 1907 nm.

In recent years, there has been a rapid growth in studies of the optoelectronic properties of graphene, carbon nanotubes (CNTs), and their derivatives. The chemical functionalization of graphene and CNTs is a key requirement for the development of this field, but it remains a significant challenge. The focus here is on recent advances in constructing nanohybrids of graphene or CNTs covalently linked to porphyrins or phthalocyanines, as well as their application in nonlinear optics. Following a summary of the syntheses of nanohybrids constructed from graphene or CNTs and porphyrins or phthalocyanines, explicit intraconjugate electronic interactions between photoexcited porphyrins/phthalocyanines and graphene/CNTs are introduced classified by energy transfer, electron transfer, and charge transfer, and their optoelectronic applications are also highlighted. The major current challenges for the development of covalently linked nanohybrids of porphyrins or phthalocyanines and carbon nanostructures are also presented.

The performance of the CAM-B3LYP, ωB97X and LC-BLYP long-range corrected density functional theory methods in the calculation of molecular first hyperpolarizabilities (β) and low-lying charge transfer (CT) excitation energies of the metal alkynyl complexes M(C≡C-4-C6 H4 -1-NO2 )(κ2 -dppe)(η5 -C5 H5 ) [M=Fe (1), Ru (2), Os (3)] and trans-[Ru{C≡C-(1,4-C6 H4 C≡C)n -4-C6 H4 -1-NO2 }Cl(κ2 -dppm)2 ] [n=0 (4), 1 (5), 2 (6)] was assessed. The BLYP, B3LYP and PBE0 standard exchange-correlation functionals and the Hartree-Fock method were also examined. The BLYP functional was shown to perform poorly in the calculation of β and low-energy CT transitions. The hybrid functionals (B3LYP and PBE0) showed significant improvement over the pure functional BLYP, but overestimated the hyperpolarizability ratios and the wavelengths of the lowest energy metal-to-ligand CT transitions for 5 and 6. The effect of long-range corrections is noteworthy, particularly for the larger complexes, improving the calculation of β ratios for 4-6. However, CAM-B3LYP, ωB97X, and LC-BLYP considerably overestimated the low-lying CT energies. PBE0 was found to give the best transition energy match for 4. The influence of the phenylene ring orientation in the alkynyl ligand on the calculated properties is substantial, particularly for the larger complexes. For these types of calculations, a basis set with diffuse functions (at least 6-31+G(d)) for the heavy elements is recommended.

The first non-centrosymmetric mixed-alkali-metal borophosphates, Na

Very large molecular two- and three-photon absorption cross-sections are achieved by appending ligated bis(diphosphine)ruthenium units to oligo(p-phenyleneethynylene)- (OPE)-based "stars" with arms up to 7 PE units in length. Extremely large three- and four-photon absorption cross sections through the telecommunications wavelengths range and beyond are obtained with these complexes on optimizing OPE length and ruthenium-coordinated peripheral ligand. MPA cross-sections are optimized at the stars with arms 2 PE units in length. Peripheral ligand variation modifies MPA merit and, in particular, 4-nitrophenylethynyl ligand incorporation enhances maximal MPA values and "switches on" four-photon absorption (4PA) in these low molecular weight complexes. The 4-nitrophenylethynyl-ligated 2PA-armed star possesses a maximal four-photon absorption cross-section of 1.8 x 10-108 cm8 s3 at 1750 nm and significant activity extending beyond 2000 nm.

Two novel noncentrosymmetric metal borates, Ba

The mono- to tri-substituted decaruthenium cluster anions [Ru10(μ-H)(μ6-C)(CO)24–x(L)x]- [L = P(C6H4Me-4)3, AsPh3, SbPh3, x = 1–3] were prepared as their [PPh4]+ salts in moderate to good yields from reaction of [PPh4][Ru10(μ-H)(μ6-C)(CO)24] with the corresponding group 15 ligands at room temperature in acetone. The tetrakis-substituted cluster Ru10(μ6-C)(μ3-CO)(μ-CO)(CO)19{P(C6H4Me-4)3}4 was obtained in high yield from [PPh4]2[Ru10(μ6–C)(CO)24] and an excess of the phosphine under the same conditions; a single-crystal X-ray diffraction study revealed that the phosphines ligate at the vertices of the “giant tetrahedral” core. Kinetics studies of the formation of [PPh4][Ru10(μ-H)(μ6-C)(AsPh3)2(CO)22] from [PPh4][Ru10(μ-H)(μ6-C)(AsPh3)(CO)23] shows that ligand substitution at these giant tetrahedral clusters proceeds via a strongly associative pathway with the likely intermediacy of a Ru-Ru bond-cleaved intermediate.

Cobalt phosphide (Co 2 P) nanorods are found to exhibit efficient catalytic activity for the hydrogen evolution reaction (HER), with the overpotential required for the current density of 20 mA/cm 2 as small as 167 mV in acidic solution and 171 mV in basic solution. In addition, the Co 2 P nanorods can work stably in both acidic and basic solution during hydrogen production. This performance can be favorably compared to typical high efficient non-precious catalysts, and suggests the promising application potential of Co 2 P nanorods in the field of hydrogen production. The HER process follows a Volmer–Heyrovsky mechanism, and the rates of the discharge step and desorption step appear to be comparable during the HER process. The similarity of charged natures of Co and P in the Co 2 P nanorods to those of the hydride-acceptor and proton-acceptor in highly efficient Ni 2 P catalysts, [NiFe] hydrogenase, and its analogues implies that the HER catalytic activity of the Co 2 P nanorods might be correlated with the charged natures of Co and P.

Reduced graphene oxide (RGO) has been covalently functionalized with porphyrin moieties by two methods: A straightforward Prato reaction (i.e. a 1,3-dipolar cycloaddition) with sarcosine and a formyl-containing porphyrin, and a stepwise method that involves a 1,3-dipolar cycloaddition to the RGO surface using 4-hydroxybenzaldehyde, followed by nucleophilic substitution with an appropriate porphyrin. The chemical bonding of porphyrins to the RGO surface has been confirmed by ultraviolet/visible absorption, fluorescence, Fourier-transform infrared, and Raman spectroscopies, X-ray powder diffraction and X-ray photoelectron spectroscopy, transmission electron and atomic force microscopy, and thermogravimetric analysis; this chemical attachment assures efficient electron/energy transfer between RGO and the porphyrin, and affords improved optical nonlinearities compared to those of the RGO precursor and the pristine porphyrin.

Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations are reported for a set of organometallic compounds for which the first hyperpolarizability values, β, have previously been determined in the laboratory. These calculations, which utilized a variety of density functionals and basis sets, address such aspects as the implications of molecular conformation and the extent of bond delocalization on the calculated β values. We also explore here the simplification of ligands for computational expedience and the influence of incorporation or exclusion of solvent corrections on β. The results of our study are likely to be of value in guiding subsequent efforts toward the reliable predictive calculation of the first hyperpolarizabilities and linear optical properties for organometallic compounds of interest to experimentalists.

International audience; After their brief characterization, a voltammetric study of the Fe(II)/Ru(II) heterobinuclear organometallic complexes [Fe]C≡C-1,4-(C6H4)C≡C[Ru]C≡C-1,4-(C6H4)C≡CH (2), FcC≡C[Ru]C≡C-1,4-(C6H4)C≡CH (3), and PhC≡C[Ru]C≡C-1,1′-Fc(C≡CH) (4) ([Fe] = Fe(κ2-dppe)(η5-C5Me5), [Ru] = trans-Ru(κ2-dppe)2; Fc = ferrocenyl; dppe =1,2-bis(diphenylphosphino)ethane) is reported in solution. These complexes which possess pendant ethynyl groups have then been grafted onto hydrogenated silicon surfaces using a mild photochemical protocol, to yield redox-active functional interfaces (Si-2/Si-3/Si-4) that were characterized by X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry. The resulting interfaces Si-2, Si-3, and Si-4 possess surface coverages and electrochemical responses that differ significantly and that depend on the nature of the grafted molecule. While the coverages calculated for the more rigid of these systems (Si-2 and Si-3) are similar (around 10–10 mol cm–2), the significantly lower coverage achieved for Si-4 (4.3 × 10–11 mol cm–2) can be ascribed to the presence of a flexible linker between the redox sites in 4. The two grafted redox centers can be electrochemically addressed in a stepwise fashion, the species exhibiting apparent charge transfer rate constants with the Si surface that are considerably higher than those reported for many related systems (>200 s–1). Comparison between Si-2 and Si-3 reveals that the use of the ferrocenyl group instead of a “Fe(κ2-dppe)(η5-C5Me5)” moiety improves the kinetic stability of the first oxidized state and its apparent charge transfer rate constant, while also increasing the first oxidation potential. However, an enhanced fragility is observed for Si-3 and even more so for Si-4 at higher oxidation potentials; this may be related to the larger spin density present on the ferrocenyl terminus of the grafted dications 32+ and 42+, as evidenced by molecular modeling calculations. Several ways to solve this important issue are discussed in the conclusion.

Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations of the molecular structures, optical absorption spectra, and spectroelectrochemical behavior of the complexes trans-[Os(C CC6H4-4-C CH)Cl(dppe)2] (1), trans,trans-[(dppe)2ClOs(C CC6H4-4-C C)RuCl(dppe)2] (2), trans,trans-[(dppe)2ClOs(C CC6H4-4-C C)Ru(C CC6H4-4-C CH)(dppe)2] (3), trans-[Os(C CC6H4-4-C CC6H4-4-C CH)Cl(dppe)2] (4), and trans,trans-[(dppe)2ClOs(C CC6H4-4-C CC6H4-4-C C)RuCl(dppe)2] (5) were undertaken. The calculated structures for the mononuclear osmium complexes 1 and 4 are in good agreement with the X-ray data, a 0.3 A lengthening of the Os–Cl bond in proceeding from the theoretical model for 4 to the experimental structure being rationalized on the basis of intermolecular H-bonding effects for the latter. For the non-oxidized forms of these five complexes, the lowest-energy bands are assigned to MLCT transitions along the main molecular axis from orbitals with mostly Os d, Cl p and alkynyl character to orbitals on the alkynyl backbone. The calculations indicate that the heterobimetallic complexes 2, 3 and 5 do not undergo metal-centred oxidation. Instead, the electron is lost from an orbital that is delocalized across the bridge and both metal centres. The mono-oxidized and di-oxidized species show new bands in the low-energy region arising from LMCT transitions, primarily corresponding to transitions from the dppe ligands to metal- and alkynyl-based orbitals. For structures involving two or more phenylethynyl units along the main axis of the molecule, the TD-DFT calculations are in significantly better agreement with the observed spectra when the phenyl groups adopt a non-coplanar conformation.

[Extract] This special issue on Coordination Chemistry in Australia comes 20 years after its predecessor and combines current activities in Australia with submissions from participants at the 6th Asian Coordination Chemistry Conference (ACCC6) that was held as part of the RACI Centenary Congress in July 2017.

Supplementary materials: CCDC 928736, 928273, 928738, 928275, 928274 and 928737 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/data_request/cif; International audience; Ortho-lithiated N,N-dimethylaminomethyl ferrocene and benzyldimethylamine react with Cp*Fe(CO)2I to give the new complexes ((Cp*Fe(CO)2)-2-(CH2NMe2)C5H3)Fe(Cp) and Cp*Fe(CO)2-C6H4(o-CH2NMe2). Access to a wide variety of alkoxy-substituted complexes ((Cp*Fe(CO)2)-2-(CH2OR)C5H3)Fe(Cp) can be easily achieved by tandem quaternization/alcoholysis of ((Cp*Fe(CO)2)-2-(CH2NMe2)C5H3)Fe(Cp). Preliminary results show that chelated complexes can be obtained by displacement of one of the carbonyl ligands by photolysis. Crystal structures of ((Cp*Fe(CO)2)-2-(CH2NMe2)C5H3)Fe(Cp), ((Cp*Fe(CO)2)-2-(CH2OR)C5H3)Fe(Cp) (R = Ph, Bz, CHPh2 and d-menthyl) and [Cp*Fe(CO)2-C6H4(o-CH2NMe2)][I] are reported.

Metal cluster core expansion at tetrahedral group 6-group 9 mixed-metal clusters MIr3(μ-CO)3(CO)8(η(5)-L) (M = W, Mo, L = C5H5; M = Mo, L = C5Me5) with the iridium capping reagents Ir(CO)2(η(5)-L') (L' = C5Me5, C5Me4H) in refluxing toluene afforded the trigonal-bipyramidal clusters MIr4(μ-CO)3(CO)7(η(5)-C5H5)(η(5)-L') (M = Mo, L' = C5Me5, 1a; M = W, L' = C5Me5, 1b; M = Mo, L' = C5Me4H, 1c; M = W, L' = C5Me4H, 1d) and MoIr4(μ3-H)(μ-CO)2(μ-η(1):η(5)-CH2C5Me4)(CO)7(η(5)-C5Me5) (2). Related reactions with M2Ir2(μ-CO)3(CO)7(η(5)-L)2 (M = W, Mo, L = C5H5; M = Mo, L = C5Me5) afforded M2Ir3(μ-CO)3(CO)6(η(5)-C5H5)2(η(5)-L') (M = Mo, L' = C5Me5, 3a; M = W, L' = C5Me5, 3b; M = Mo, L' = C5Me4H, 3c; M = W, L' = C5Me4H, 3d), W2Ir3(μ-CO)4(CO)5(η(5)-C5H5)2(η(5)-C5Me4H) (4), and Mo2Ir3(μ-CO)3(CO)6(η(5)-C5Me5)3 (5). Single-crystal X-ray diffraction studies of 1a-1d, 2, 3a-3d, and 4 confirmed their molecular structures, including the μ-η(1):η(5)-CH2C5Me4 ligand at hydrido cluster 2, derived from a C-H bond activation of one of the methyl groups. Density functional theory (DFT) studies were employed to suggest the structure of 5. The redox behavior of the new clusters was examined through cyclic voltammetry; all clusters exhibit oxidation and reduction processes (with respect to the resting state), with the oxidation processes being the more reversible, and increasingly so on decreasing Ir content of the clusters, replacing W by Mo, and increasing alkylation of the cyclopentadienyl ligands. In situ IR and UV-vis-near-IR spectroelectrochemical studies of the reversible oxidation processes in 1a and 3a were undertaken, with the spectra of the former suggesting progression to an all-terminal CO geometry concomitant with the first oxidation and a significant structural change upon the second oxidation step. DFT studies of 1a revealed that its crystallographically-confirmed Mo-equatorial core geometry is essentially isoenergetic with a possible Mo-apical isomer, and identified several bridging CO structures for the charged states.

The synthesis of Ru(C CC6H4-4-NO2)(κ2-dppf)(η5-C5H5) (1) is reported, together with spectroscopic, X-ray structural, linear optical and quadratic nonlinear optical (NLO) studies of 1 and Ru(C CPh)(κ2-dppf)(η5-C5H5) (2), the last-mentioned using the hyper-Rayleigh scattering technique at 1064 nm. Quadratic nonlinearities for these dppf-containing complexes are comparable to those of their dppe-containing analogues and significantly greater than carbonyl-containing analogues. The linear optical and quadratic NLO properties of 1, 2 and their dppe-containing analogues have been rationalized by time-dependent density functional theory calculations.

Two graphene oxide (GO)-based nanohybrid materials possessing covalent linkages to axially-coordinated tetraphenylporphyrin (TPP), GO–TPP, were prepared and were characterized by Fourier transform infrared (FT-IR), Ultraviolet–visible (UV–Vis) absorption, steady state fluorescence, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), thermogravimetric analysis (TGA), elemental analysis and Raman spectroscopic techniques. The nonlinear optical properties and optical limiting performance of GO, GO–TPP nanohybrids and the free porphyrins dihydroxotin(IV) tetraphenylporphyrin (SnTPP) and the phosphorus-cored porphyrin (PTPP) were investigated using nanosecond and picosecond Z-scan measurements at 532 nm. At the identical mass concentration of 0.2 mg mL −1 , GO–TPP nanohybrids exhibited enhanced nonlinear optical properties and optical limiting performance, ascribed to a combination of nonlinear scattering and/or two-photon absorption with reverse saturable absorption, and the photo-induced electron or energy transfer from the electron-donor porphyrin moiety to the acceptor graphene.