Pt(II) bipyridyl complexes bearing substituted fluorenyl motif on the bipyridyl and acetylide ligands : synthesis, photophysics, and reverse saturable absorption

A series of Pt(II) diimine complexes bearing benzothiazolylfluorenyl (BTZ-F8), diphenylaminofluorenyl (NPh2- F8), or naphthalimidylfluorenyl (NI-F8) motifs on the bipyridyl or acetylide ligands (Pt-4−Pt-8), (i.e., {4,4′-bis[7-R1-F8-(≡)n-]bpy}Pt(7- R2-F8- ≡ -)2, where F8 = 9,9′-di(2-ethylhexyl)fluorene, bpy = 2,2′- bipyridine, Pt-4: R1 = R2 = BTZ, n = 0; Pt-5: R1 = BTZ, R2 = NI, n = 0; Pt-6: R1 = R2 = BTZ, n = 1; Pt-7: R1 = BTZ, R2 = NPh2, n = 1; Pt- 8: R1 = NPh2, R2 = BTZ, n = 1) were synthesized. Their ground-state and excited-state properties and reverse saturable absorption performances were systematically investigated. The influence of these motifs on the photophysics of the complexes was investigated by spectroscopic methods and simulated by time-dependent density functional theory (TDDFT). The intense absorption bands below 410 nm for these complexes is assigned to predominantly 1π,π* transitions localized on either the bipyridine or the acetylide ligands; while the broad low-energy absorption bands between 420 and 575 nm are attributed to essentially 1MLCT (metal-to-ligand charge transfer)/ 1LLCT (ligand-to-ligand charge transfer) transitions, likely mixed with some 1ILCT (intraligand charge transfer) transition for Pt-4−Pt-7, and predominantly 1ILCT transition admixing with minor 1MLCT/1LLCT characters for Pt-8. The different substituents on the acetylide and bipyridyl ligands, and the degrees of π-conjugation in the bipyridyl ligand influence both the 1π,π* and charge transfer transitions pronouncedly. All complexes are emissive at room temperature. Upon excitation at their respective absorption band maxima, Pt-4, Pt-6, and Pt-8 exhibit acetylide ligand localized 1π,π* fluorescence and 3MLCT/3LLCT phosphorescence in CH2Cl2, while Pt-5 manifests 1ILCT fluorescence and 3ILCT phosphorescence. However, only 1LLCT fluorescence was observed for Pt-7 at room temperature. The nanosecond transient absorption study was carried out for Pt-4−Pt-8 in CH3CN. Except for Pt-7 that contains NPh2 at the acetylide ligands, Pt-4−Pt-6 and Pt-8 all exhibit weak to moderate excited-state absorption in the visible spectral region. Reverse saturable absorption (RSA) of these complexes was demonstrated at 532 nm using 4.1 ns laser pulses in a 2 mm cuvette. The strength of RSA follows this trend: Pt-4 > Pt-5 > Pt-7 > Pt-6 > Pt-8. Incorporation of electron-donating substituent NPh2 on the bipyridyl ligand significantly decreases the RSA, while shorter π-conjugation in the bipyridyl ligand increases the RSA. Therefore, the substituent at either the acetylide ligands or the bipyridyl ligand could affect the singlet and triplet excited-state characteristics significantly, which strongly influences the RSA efficiency.

Inter-cycle variability of ignition delay in an ethanol fumigated common rail diesel engine

An experimental study has been performed to investigate the ignition delay of a modern heavy-duty common-rail diesel engine run with fumigated ethanol substitutions up to 40% on an energy basis. The ignition delay was determined through the use of statistical modelling in a Bayesian framework this framework allows for the accurate determination of the start of combustion from single consecutive cycles and does not require any differentiation of the in-cylinder pressure signal. At full load the ignition delay has been shown to decrease with increasing ethanol substitutions and evidence of combustion with high ethanol substitutions prior to diesel injection have also been shown experimentally and by modelling. Whereas, at half load increasing ethanol substitutions have increased the ignition delay. A threshold absolute air to fuel ratio (mole basis) of above ~110 for consistent operation has been determined from the inter-cycle variability of the ignition delay, a result that agrees well with previous research of other in-cylinder parameters and further highlights the correlation between the air to fuel ratio and inter-cycle variability. Numerical modelling to investigate the sensitivity of ethanol combustion has also been performed. It has been shown that ethanol combustion is sensitive to the initial air temperature around the feasible operating conditions of the engine. Moreover, a negative temperature coefficient region of approximately 900{1050 K (the approximate temperature at fuel injection) has been shown with for n-heptane and n-heptane/ethanol blends in the numerical modelling. A consequence of this is that the dominate effect influencing the ignition delay under increasing ethanol substitutions may rather be from an increase in chemical reactions and not from in-cylinder temperature. Further investigation revealed that the chemical reactions at low ethanol substitutions are different compared to the high (> 20%) ethanol substitutions.

Double star chopper cell converter for battery electric vehicles with inter-module SoC balancing and fault tolerant control

A modularized battery system with Double Star Chopper Cell (DSCC) based modular multilevel converter is proposed for a battery operated electric vehicle (EV). A design concept for the modularized battery micro-packs for DSCC is described. Multidimensional pulse width modulation (MD-PWM) with integrated inter-module SoC balancing and fault tolerant control is proposed and explained. The DSCC can be operated either as an inverter to drive the EV motor or as a synchronous rectifier connected to external three phase power supply equipment for charging the battery micro-packs. The methods of operation as inverter and synchronous rectifier with integrated inter-module SoC balancing and fault tolerant control are discussed. The proposed system operation as inverter and synchronous rectifier are verified through simulations and the results are presented.

Improving out-domain PLDA speaker verification using unsupervised inter-dataset variability compensation approach

Experimental studies have found that when the state-of-the-art probabilistic linear discriminant analysis (PLDA) speaker verification systems are trained using out-domain data, it significantly affects speaker verification performance due to the mismatch between development data and evaluation data. To overcome this problem we propose a novel unsupervised inter dataset variability (IDV) compensation approach to compensate the dataset mismatch. IDV-compensated PLDA system achieves over 10% relative improvement in EER values over out-domain PLDA system by effectively compensating the mismatch between in-domain and out-domain data.

Wide-area damping control for inter-area oscillations using inverse filtering technique

In this study, a non-linear excitation controller using inverse filtering is proposed to damp inter-area oscillations. The proposed controller is based on determining generator flux value for the next sampling time which is obtained by maximising reduction rate of kinetic energy of the system after the fault. The desired flux for the next time interval is obtained using wide-area measurements and the equivalent area rotor angles and velocities are predicted using a non-linear Kalman filter. A supplementary control input for the excitation system, using inverse filtering approach, to track the desired flux is implemented. The inverse filtering approach ensures that the non-linearity introduced because of saturation is well compensated. The efficacy of the proposed controller with and without communication time delay is evaluated on different IEEE benchmark systems including Kundur's two area, Western System Coordinating Council three-area and 16-machine, 68-bus test systems.

The molecular structure of kaolinite–potassium acetate intercalation complexes: A combined experimental and molecular dynamic simulation study

The kaolinite (Kaol) intercalated with potassium acetate (Ac) was prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry. Molecular dynamic simulation was performed to investigate the structure of Kaol–Ac intercalation complex and the hydrogen bonds between Kaol and intercalated Ac andwater using INTERFACE forcefield. The acetate anions andwater arranged in a bilayer structure in the interlayer space of Kaol. The potassium cations distributed in the interlayer space and strongly coordinated with acetate anions aswell aswater rather than keyed into the ditrigonal holes of tetrahedral surface of Kaol. Strong hydrogen bonds formed between the hydrogen atoms of hydroxyl on the octahedral surface and oxygen atoms of both acetate anions and water. The acetate anions andwater also weakly bonded hydrogen to the silica tetrahedral surface through their hydrogen atoms with the oxygen atoms of silica tetrahedral surface.

New insights into the molecular structure of kaolinite–methanol intercalation complexes

A series of kaolinite–methanol complexes with different basal spacings were synthesized using guest displacement reactions of the intercalation precursors kaolinite–N-methyformamide (Kaol–NMF), kaolinite–urea (Kaol–U), or kaolinite–dimethylsulfoxide (Kaol–DMSO), with methanol (Me). The interaction of methanol with kaolinite was examined using X-ray diffraction (XRD), infrared spectroscopy (IR), and nuclear magnetic resonance (NMR). Kaolinite (Kaol) initially intercalated with N-methyformamide (NMF), urea (U), or dimethylsulfoxide (DMSO) before subsequent reaction with Me formed final kaolinite–methanol (Kaol–Me) complexes characterized by basal spacing ranging between 8.6 Å and 9.6 Å, depending on the pre-intercalated reagent. Based on a comparative analysis of the three Kaol–Me displacement intercalation complexes, three types of Me intercalation products were suggested to have been present in the interlayer space of Kaol: (1) molecules grafted onto a kaolinite octahedral sheet in the form of a methoxy group (Al-O-C bond); (2) mobile Me and/or water molecules kept in the interlayer space via hydrogen bonds that could be partially removed during drying; and (3) a mixture of types 1 and 2, with the methoxy group (Al-O-C bond) grafted onto the Kaol sheet and mobile Me and/or water molecules coexisted in the system after the displacement reaction by Me. Various structural models that reflected four possible complexes of Kaol–Me were constructed for use in a complimentary computational study. Results from the calculation of the methanol kaolinite interaction indicate that the hydroxyl oxygen atom of methanol plays the dominant role in the stabilization and localization of the molecule intercalated in the interlayer space, and that water existing in the intercalated Kaol layer is inevitable.

Seasonal and spatial variations in rare earth elements to identify inter-aquifer linkages and recharge processes in an Australian catchment

With the aim of elucidating the seasonal behaviour of rare earth elements (REEs), surface and groundwaters were collected under dry and wet conditions in different hydrological units of the Teviot Brook catchment (Southeast Queensland, Australia). Sampled waters showed a large degree of variability in both REE abundance and normalised patterns. Overall REE abundance ranged over nearly three orders of magnitude, and was consistently lower in the sedimentary bedrock aquifer (18ppt<∑REE<477ppt) than in the other hydrological systems studied. Abundance was greater in springs draining rhyolitic rocks (∑REE=300 and 2054ppt) than in springs draining basalt ranges (∑REE=25 and 83ppt), yet was highly variable in the shallow alluvial groundwater (16ppt<∑REE<5294ppt) and, to a lesser extent, in streamwater (85ppt<∑REE<2198ppt). Generally, waters that interacted with different rock types had different REE patterns. In order to obtain an unbiased characterisation of REE patterns, the ratios between light and middle REEs (R(M/L)) and the ratios between middle and heavy REEs (R(H/M)) were calculated for each sample. The sedimentary bedrock aquifer waters had highly evolved patterns depleted in light REEs and enriched in middle and heavy REEs (0.17

Inter-organisational characteristics of resilience in a post-disaster recovery context

During post-disaster recovery, an infrastructure system may be subject to a number of disturbances originating from several other interdependent infrastructures. These disturbances might result in a series of system failures, thereby having immediate impact on societal living conditions. The inability to detect signs of disturbance from one infrastructure during recovery might cause significant disruptive effects on other infrastructure via the interconnection that exist among them. In such circumstances, it clearly appears that critical infrastructures' interdependencies affect the recovery of each individual infrastructure, as well as those of other interdependent infrastructure systems. This is why infrastructure resilience needs to be improved in function of those interdependencies, particularly during the recovery period to avoid the occurrence of a ‘disaster of disaster’ scenario. Viewed from this perspective, resilience is achieved through an inter-organisational collaboration between the different organisations involved in the reconstruction of interdependent infrastructure systems. This paper suggests that to some extent, the existing degree of interconnectedness between these infrastructure systems can also be found in their resilience ability during post-disaster recovery. For instance, without a resilient energy system, a large-scale power outage could affect simultaneously all the interdependent infrastructures after a disaster. Thus, breaking down the silos of resilience would be the first step in minimizing the risks of disaster failures from one infrastructure to cascade or escalate to other interconnected systems.

Evaluation of Australian Performing Arts Market 2014-2018: APAM inter-year report 2015

In the awarding of the tender for APAM by the Australia Council to Brisbane Powerhouse for the delivery of the market in 2014-2018, a requirement is that a formal evaluation of the three iterations of APAM be undertaken by the Queensland University of Technology, Creative Industries Faculty, under the leadership of Associate Professor Sandra Gattenhof. The agreed research model delivers reporting on outcomes not only in the year in which APAM is delivered (2014, 2016, 2018) but also in the years between (2015, 2017). This inter-year report focuses on the domestic and international touring outcomes resulting from engagement in the 2014 Market and responds two of the three key research foci for the evaluation that are articulated in the Brisbane Powerhouse Tender (2011) document as: • Evaluation of international market development outcomes through showcasing work to targeted international presenters and agents • Evaluation of national market development outcomes through showcasing work to national presenters and producers. The reporting for mid-year 2015, a non-APAM year, collects data from two key sources – six identified case study productions that have been tracked for eighteen months, and an online survey delivered to all APAM 2014 delegates. This inter-year report is a six month follow-up with delegates and identified case studies companies that track the ongoing progress of market outcomes and levers for ongoing improvement of the APAM delivery model that was tabled in the Year One Report delivered to Brisbane Powerhouse in October 2014.

On the biomechanical significance of inter-lamellar interfaces in the intervertebral disc

The intervertebral disc (IVD) is a unique soft tissue structure which provides structural support and flexibility in the axial skeleton of vertebrates. From a structural perspective, the disc behaves somewhat like a thick walled pressure vessel, where the walls are comprised of a series of composite annular rings (lamellae). However, a prior study (Marchand and Ahmed, 1990) found a high proportion of circumferentially discontinuous lamellae in human lumbar IVDs. The presence of these discontinuities raises important structural questions, because discontinuous lamellae cannot withstand high nucleus pressures via the generation of circumferential (hoop) stress. A possible alternative mechanism may be that inter-lamellar cohesion allows shear stress transfer between adjacent annular layers. The aim of the present study was therefore to investigate the importance of inter-lamellar shear resistance in the intervertebral disc. This work found that inter-lamellar shear resistance has a strong influence on the compressive stiffness of the intervertebral disc, with a change in interface condition from tied (no slip) to frictionless (no shear resistance) reducing disc compressive stiffness by 40%. However, it appears that substantial inter-lamellar shear resistance is present in the bovine tail disc. Decreases in inter-lamellar shear resistance due to degradation of bridging collagenous or elastic fibre structures could therefore be an important part of the process of disc degeneration.

Two-dimensional coordination polymeric structures in caesium complexes with ring-substituted phenoxyacetic acids

The two-dimensional polymeric structures of the caesium complexes with the phenoxyacetic acid analogues (4-fluorophenoxy)acetic acid, (3-chloro-2-methylphenoxy)acetic acid and the herbicidally active (2,4-dichlorophen­oxy)acetic acid (2,4-D), namely poly[[5-(4-fluorophenoxy)acetato][4-(4-fluorophenoxy)acetato]dicaesium], [Cs2(C8H6FO3)2]n, (I), poly[aqua[5-(3-chloro-2-methylphenoxy)acetato]caesium], [Cs(C9H8ClO3)(H2O)]n, (II), and poly[[7-(2,4-di­chlorophenoxy)acetato][(2,4-dichlorphenoxy)acetic acid]caesium], [Cs(C8H5Cl2O3)(C8H6Cl2O3)]n, (III), are described. In (I), the Cs+ cations of the two individual irregular coordination polyhedra in the asymmetric unit (one CsO7 and the other CsO8) are linked by bridging carboxylate O-atom donors from the two ligand molecules, both of which are involved in bidentate chelate Ocarboxy,Ophenoxy interactions, while only one has a bidentate carboxylate O,O'-chelate inter­action. Polymeric extension is achieved through a number of carboxylate O-atom bridges, with a minimum CsCs separation of 4.3231 (9) Å, giving layers which lie parallel to (001). In hydrated complex (II), the irregular nine-coordination about the Cs+ cation comprises a single monodentate water molecule, a bidentate Ocarboxy,Ophenoxy chelate interaction and six bridging carboxylate O-atom bonding interactions, giving a CsCs separation of 4.2473 (3) Å. The water mol­ecule forms intralayer hydrogen bonds within the two-dimensional layers, which lie parallel to (100). In complex (III), the irregular centrosymmetric CsO6Cl2 coordination environment comprises two O-atom donors and two ring-substituted Cl-atom donors from two hydrogen bis[(2,4-dichlorophenoxy)acetate] ligand species in a bidentate chelate mode, and four O-atom donors from bridging carboxyl groups. The duplex ligand species lie across crystallographic inversion centres, linked through a short O-HO hydrogen bond involving the single acid H atom. Structure extension gives layers which lie parallel to (001). The present set of structures of Cs salts of phenoxyacetic acids show previously demonstrated trends among the alkali metal salts of simple benzoic acids with no stereochemically favourable interactive substituent groups for formation of two-dimensional coordination polymers.

Amidinato- and triazenido-bridged binuclear complexes of palladium and platinum

The reaction of [M2Cl2(mu-Cl)(2)(PR3)(2)] (M=Pd or Pt; PR3=PEt3, PBu3, PMe2Ph, PMePh2) with lithium amidinate or sodium triazenide gave binuclear complexes containing amidinato- or triazenido-bridges, [M2Cl2(mu-ArNENAr)(2)(PR3)(2)] (E=CH, CMe or N). These complexes were characterized by elemental analysis and NMR (H-1, P-31 or Pt-195) data. The structures of two complexes, [(PdCl2)-Cl-2(mu-PhNC(Me)NPh)(2)(PMe2Ph)(2)] (10) and [Pt2Cl2(mu-PhNNNPh)(2)(PEt3)(2)] (11) were established by single crystal X-ray structural analyses. The Pt-195 NMR data Show coupling between two metal centers in the cis triazenido-bridged complex. The corresponding amidinate bridged complex does not show coupling. The role of the bridging ligand in mediating interaction between the metal centers is probed through Extended Huckel Theory (EHT) calculations. It is suggested that M-M interactions are primarily affected by the bridging ligands

Synthesis, X-ray structures, and spectroscopic and electrochemical properties of (mu-oxo)bis(mu-carboxylato)diruthenium complexes having six imidazole bases as terminal ligands

Complexes [Ru2O(O2CR)(2)(1-MeIm)(6)](ClO4)(2) (la-c), [Ru2O(O2CR)(2)(ImH)(6)](ClO4)(2) (2a,b), and [Ru2O(O2CR)(2)(4-MeImH)(6)](ClO4)(2) (3a,b) with a (mu-oxo)bis(mu-carboxylato)diruthenium(III) core have been prepared by reacting Ru2Cl(O2CR)(4) with the corresponding imidazole base, viz. 1-methylimidazole (1-MeIm), imidazole (ImH), and 4-methylimidazole (4-MeImH) in methanol, followed by treatment with NaClO4 in water (R: Me, a; C6H4-p-OMe, b; C6H4-p-Me, c). Diruthenium(III,IV) complexes [Ru2O(O2CR)(2)(1-MeIm)(6)](ClO4)(3) (R: Me, 4a; C6H4-p-OMe, 4b; C6H4-p-Me, 4c) have been prepared by one-electron oxidation of 1 in MeCN with K2S2O8 in water. Complexes la, 2a . 3H(2)O, and 4a . 1.5H(2)O have been structurally characterized. Crystal data for the complexes are as follows: la, orthorhombic, P2(1)2(1)2(1), a = 7.659(3) Angstrom, b = 22.366(3) Angstrom, c = 23.688(2) Angstrom, V = 4058(2) Angstrom(3), Z = 4, R = 0.0475, and R-w = 0.0467 for 2669 reflections with F-o > 2 sigma(F-o); 2a . 3H(2)O, triclinic, , a = 13.735(3) Angstrom, b = 14.428(4) Angstrom, c = 20.515(8) Angstrom, alpha = 87.13(3)degrees, beta = 87.61(3)degrees, gamma = 63.92(2)degrees, V = 3646(2) Angstrom(3), Z = 4, R = 0.0485 and R-w = 0.0583 for 10 594 reflections with F-o > 6 sigma(F-o); 4a . 1.5H(2)O triclinic, , a = 11.969(3) Angstrom, b = 12.090(6) Angstrom, c = 17.421(3) Angstrom, alpha = 108.93(2)degrees, beta = 84.42(2)degrees, gamma = 105.97(2)degrees, V = 2292(1) Angstrom(3), Z = 2, R = 0.0567, and R-w = 0.0705 for 6775 reflections with F-o > 6 sigma(F-o). The complexes have a diruthenium unit held by an oxo and two carboxylate ligands, and the imidazole ligands occupy the terminal sites of the core. The Ru-Ru distance and the Ru-O-oxo-Ru angle in la and 2a . 3H(2)O are 3.266(1), 3.272(1) Angstrom and 122.4(4), 120.5(2)degrees, while in 4a . 1.5H(2)O these values are 3.327(1) Angstrom and 133.6(2)degrees. The diruthenium(III) complexes 1-3 are blue in color and they exhibit an intense visible band in the range 560-575 nm. The absorption is charge transfer in nature involving the Ru(III)-d pi and O-oxo-p pi orbitals. The diruthenium(III,IV) complexes are red in color and show an intense band near 500 nm. The diruthenium(III) core readily gets oxidized with K2S2O8 forming quantitatively the diruthenium(III,IV) complex. The visible spectral record of the conversion shows an isosbestic point at 545 nm for 1 and at 535 nm for 2 and 3. Protonation of the oxide bridge by HClO4 in methanol yields the [Ru-2(mu-OH)(mu-O2CR)(2)](3+) core. The hydroxo species shows a visible band al 550 nm. The pK(a) value for la is 2.45. The protonated species are unstable. The 1-MeIm species converts to the diruthenium(III,IV) core, while the imidazole complex converts to [Ru(ImH)(6)](3+) and some uncharacterized products. Complex [Ru(ImH)(6)](ClO4)(3) has been structurally characterized. The diruthenium(III) complexes are essentially diamagnetic and show characteristic H-1 NMR spectra indicating the presence of the dimeric structure in solution. The diruthenium(III,IV) complexes are paramagnetic and display rhombic EPR spectral features. Complexes 1-3 are redox active. Complex 1 shows the one-electron reversible Ru-2(III)/(RuRuIV)-Ru-III, one-electron quasireversible (RuRuIV)-Ru-III/Ru-2(IV), and two-electron quasireversible Ru-2(III)/Ru-2(II) couples near 0.4, 1.5, and -1.0 V vs SCE In MeCN-0.1 M TBAP, respectively, in the cyclic and differential pulse voltammetric studies. Complexes 2 and 3 exhibit only reversible Ru-2(III)/(RuRuIV)-Ru-III and the quasireversible (RuRuIV)-Ru-III/Ru-2(IV) couples near 0.4 and 1.6 V vs SCE, respectively, The observation of a quasireversible one-step two-electron transfer reduction process in 1 is significant considering its relevance to the rapid and reversible Fe-2(III)/Fe-2(II) redox process known for the tribridged diiron core in the oxy and deoxy forms of hemerythrin.

X-ray studies on crystalline complexes involving amino acids and peptides. XXXIII. Crystal structures of L- and DL-arginine complexed with oxalic acid and a comparative study of amino acid oxalic acid complexes

The DL- and L-arginine complexes of oxalic acid are made up of zwitterionic positively charged amino acid molecules and semi-oxalate ions. The dissimilar molecules aggregate into separate alternating layers in the former. The basic unit in the arginine layer is a centrosymmetric dimer, while the semi-oxalate ions form hydrogen-bonded strings in their layer. In the L-arginine complex each semi-oxalate ion is surrounded by arginine molecules and the complex can be described as an inclusion compound. The oxalic acid complexes of basic amino acids exhibit a variety of ionization states and stoichiometry. They illustrate the effect of aggregation and chirality on ionization state and stoichiometry, and that of molecular properties on aggregation. The semi-oxalate/oxalate ions tend to be planar, but large departures from planarity are possible. The amino acid aggregation in the different oxalic acid complexes do not resemble one another significantly, but the aggregation of a particular amino acid in its oxalic acid complex tends to have similarities with its aggregation in other structures. Also, semi-oxalate ions aggregate into similar strings in four of the six oxalic acid complexes. Thus, the intrinsic aggregation propensities of individual molecules tend to be retained in the complexes.