Ambient Chemical Fixation of CO2 Using a Robust Ag27 Cluster-Based Two-Dimensional Metal-Organic Framework.

Unprecedented double S2- templated Ag27 clusters have been stabilized by 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP-H2 ) ligands to afford a robust 2D metal-organic framework (Ag27-MOF). This silver cluster-assembled material serves as a highly efficient heterogeneous catalyst for the cyclization of both terminal and internal propargylamines with CO2 under atmospheric pressure. Density functional theory (DFT) calculations illustrate that the high catalytic activity and broad substrate scope are attributable to the saddle-shaped metallic node in Ag27-MOF, which features an accessible platform with high-density silver atoms as π-Lewis acid sites for activating C≡C triple bonds. As a result, different sterically hindered alkyne substrates can be effectively activated through π-interactions with these cationic silver centers.

Bifurcated Hydrogen-Bond-Stabilized Boron Analogues of Carboxylic Acids.

The reactivity of a bulky m-terphenylboronic acid, DmpB(OH)2 [1; Dmp = 2,6-bis(2,4,6-trimethylphenyl)phenyl], toward three different N-heterocyclic carbenes has been examined. The reaction of 1 with 1 equiv of bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) leads to the formation of a hydrogen-bonded carbene boronic acid adduct, 2, featuring strong O-H···C contacts. In contrast, more basic 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (IPr2Me2) and 1,3-di-tert-butylimidazol-2-ylidene (ItBu) deprotonate 1 smoothly to afford the rare anionic boranuidacarboxylic acids 3 and 4, respectively. Structural determination reveals that 3 and 4 bear unprecedented bifurcated hydrogen bonds with a BO- unit as a double hydrogen-bond acceptor, which contribute significantly to stabilization of the highly reactive B═O double bond. Quantum-mechanical calculations were conducted to disclose the unique electronic properties of the multiple bonds, as well as the important hydrogen bonds in these compounds.

New trends in removing heavy metals from wastewater.

With the development of researches, the treatments of wastewater have reached a certain level. Whereas, heavy metals in wastewater cause special concern in recent times due to their recalcitrance and persistence in the environment. Therefore, it is important to get rid of the heavy metals in wastewater. The previous studies have provided many alternative processes in removing heavy metals from wastewater. This paper reviews the recent developments and various methods for the removal of heavy metals from wastewater. It also evaluates the advantages and limitations in application of these techniques. A particular focus is given to innovative removal processes including adsorption on abiological adsorbents, biosorption, and photocatalysis. Because these processes have leaded the new trends and attracted more and more researches in removing heavy metals from wastewater due to their high efficency, pluripotency and availability in a copious amount. In general, the applicability, characteristic of wastewater, cost-effectiveness, and plant simplicity are the key factors in selecting the most suitable method for the contaminated wastewater.

A combined biological removal of Cd(2+) from aqueous solutions using Phanerochaete chrysosporium and rice straw.

The removal of Cd(2+) from aqueous solutions by agricultural residues rice straw combined with white rot fungus Phanerochaete chrysosporium (P. chrysosporium) was investigated. The results showed that over 99% of the total Cd(2+) (initial concentration of 150mgL(-1)) was removed at the optimal operating conditions (pH 5.0 at 35°C). We also found that P. chrysosporium could survive under Cd(2+) stress even with an initial Cd(2+) concentration of 250mgL(-1). But when Cd(2+) concentration increased to 250mgL(-1), fungus growth and reproduction were remarkably restrained, and as a result, Cd(2+) removal dropped to 59.2%. It was observed that the fungus biomass and activities of ligninolytic enzymes decreased at some degree under high concentration of Cd(2+) (above 100mgL(-1)). Also, we found that a moderate Cd(2+) stress (below 150mgL(-1)) could stimulate P. chrysosporium's production of the heavy metals chelator - oxalate. This study will provide useful information for the application of biological removal of heavy metal irons from wastewater.

The stability of Pb species during the Pb removal process by growing cells of Phanerochaete chrysosporium.

Extensive studies have been operated on the biosorption of heavy metal using white-rot fungi, whereas information on the stability of the sorbed metal species has never been taken into consideration, which is important for the later disposal of the used biomass. In this study, the growing cells of Phanerochaete chrysosporium were used to remove Pb from the fungal living environment. The bioremoval of Pb proceeded continually until 121 h. The bioremoved Pb was found to be stabilized at the first time P. chrysosporium was exposed to Pb ions. The extractable rate of removed Pb decreased constantly and kept at a stable level around 20 % after 121 h. The results indicated that the growing biomass is efficient for the stabilization of Pb, and the used biomass was suitable to be separated for further disposal at 121 h. With environment scanning electron microscopy coupled with energy-dispersive X-ray analysis (ESEM-EDAX) and X-ray powder diffraction (XRD) analysis, the stabilized Pb species were identified to be lead oxalate and lead chloride phosphate. Further, it is found that the stabilization of Pb by growing P. chrysosporium is not strictly limited in the aspect of pH when pH in the environment is in the range of 4-6.

Cadmium induced oxalic acid secretion and its role in metal uptake and detoxification mechanisms in Phanerochaete chrysosporium.

This study examines the role of oxalic acid in the uptake of Cd and participation in detoxification process in Phanerochaete chrysosporium. Cd-induced oxalic acid secretion was observed with growth inhibition and enzyme inactivation (LiP and MnP) of P. chrysosporium. The peak value of oxalic acid concentration was 16.6 mM at initial Cd concentration of 100 mg L(-1). During the short-term uptake experiments, the uptake of Cd was enhanced and accelerated in the presence of oxalic acid and resulted in alleviated growth and enzyme inhibition ratios. The formation of a metal-oxalate complex therefore may provide a detoxification mechanism via effect on metal bioavailability, whereby many fungi can survive and grow in environments containing high concentrations of toxic metals. The present findings will advance the understanding of fungal resistance to metal stress, which could show promise for a more useful application of microbial technology in the treatment of metal-polluted waste.

Heavy metal-induced glutathione accumulation and its role in heavy metal detoxification in Phanerochaete chrysosporium.

Phanerochaete chrysosporium are known to be vital hyperaccumulation species for heavy metal removal with admirable intracellular bioaccumulation capacity. This study analyzes the heavy metal-induced glutathione (GSH) accumulation and the regulation at the intracellular heavy metal level in P. chrysosporium. P. chrysosporium accumulated high levels of GSH, accompanied with high intracellular concentrations of Pb and Cd. Pb bioaccumulation lead to a narrow range of fluctuation in GSH accumulation (0.72-0.84 µmol), while GSH plummeted under Cd exposure at the maximum value of 0.37 µmol. Good correlations between time-course GSH depletion and Cd bioaccumulation were determined (R (2) > 0.87), while no significant correlations have been found between GSH variation and Pb bioaccumulation (R (2) < 0.38). Significantly, concentration-dependent molar ratios of Pb/GSH ranging from 0.10 to 0.18 were observed, while molar ratios of Cd/GSH were at the scope of 1.53-3.32, confirming the dominant role of GSH in Cd chelation. The study also demonstrated that P. chrysosporium showed considerable hypertolerance to Pb ions, accompanied with demand-driven stimulation in GSH synthesis and unconspicuous generation of reactive oxygen stress. GSH plummeted dramatically response to Cd exposure, due to the strong affinity of GSH to Cd and the involvement of GSH in Cd detoxification mechanism mainly as Cd chelators. Investigations into GSH metabolism and its role in ameliorating metal toxicity can offer important information on the application of the microorganism for wastewater treatment.

Biochar derived from animal and plant facilitates synergistic transformation of heavy metals and phosphorus in sewage sludge composting.

This study investigated the influence of plant-derived biochar (PB) and animal-derived biochar (AB) on behavior of heavy metals and phosphorus fractions during sewage sludge composting. PB was highly effective in reducing the bioavailability of Zn and Cu by 39% and 50%, respectively, while AB decreased the bioavailability of Pb (30%) and Cd (12%). Both biochar increased available phosphorus by over 38%. Acid extractable and bioavailable Pb in AB, and water-soluble, oxidizable and total Zn, acid extractable and oxidizable Cu in PB were positively correlated with moderately resistant organic phosphorus (MROP). Besides, in AB, Cd had strong and positive correlation with highly resistant organic phosphorus (HROP). This suggested biochar facilitated the formation of stable organometallic complexes through binding metal ions to phosphorus fractions, with notable differences based on biochar source. FT-IR showed biochar promoted humification, with PB enhancing carboxyl and polysaccharide formation, while AB encouraged quinone and aryl ether structures. These surface functional groups on the biochar likely contributed to heavy metals and phosphorus binding through chelation, adsorption, and electron shuttling.

The influence of biochar from animal and plant on the transformation of phosphorus during paper mill sludge composting.

Biochar has effect on phosphorus adsorption, release, and transformation. This study compared the influence of biochar derived from animal (AB) and plant (PB) during paper mill sludge composting. Results indicated AB not only accelerated sludge decomposition but also had significantly higher levels of available phosphorus (AP) than PB and CK (no biochar), with AP contents in the order of AB > PB > CK. Compared to CK, AB was found to increase the relative abundance of thermophilic bacteria, and PB diversified the microbial community. Based on Pearson and RDA results, TOC/TN ratio (C/N) and organic matter (OM) explained above 50% of the variance in microbial community and phosphorus fractions. Thermophilic bacteria with high levels of OM and C/N promoted the conversion among labile and moderately labile organic phosphorus, moderately labile inorganic phosphorus, and AP. Biochar could enhance the AP conversion pathway, leading to increased levels of AP.

Phage lysate can regulate the humification process of composting.

Phages play a crucial role in orchestrating top-down control within microbial communities, influencing the dynamics of the composting process. Despite this, the impact of phage-induced thermophilic bacterial lysis on humification remains ambiguous. This study investigates the effects of phage lysate, derived explicitly from Geobacillus subterraneus, on simulated composting, employing ultrahigh-resolution mass spectrometry and 16S rRNA sequencing techniques. The results show the significant role of phage lysate in expediting humus formation over 40 days. Notably, the rapid transformation of protein-like precursors released from phage-induced lysis of the host bacterium resulted in a 14.8 % increase in the proportion of lignins/CRAM-like molecules. Furthermore, the phage lysate orchestrated a succession in bacterial communities, leading to the enrichment of core microbes, exemplified by the prevalence of Geobacillus. Through network analysis, it was revealed that these enriched microbes exhibit a capacity to convert protein and lignin into essential building blocks such as amino acids and phenols. Subsequently, these components were polymerized into humus, aligning with the phenol-protein theory. These findings enhance our understanding of the intricate microbial interactions during composting and provide a scientific foundation for developing engineering-ready composting humification regulation technologies.

Individuals with anxiety and depression use atypical decision strategies in an uncertain world.

Previous studies on reinforcement learning have identified three prominent phenomena: (1) individuals with anxiety or depression exhibit a reduced learning rate compared to healthy subjects; (2) learning rates may increase or decrease in environments with rapidly changing (i.e. volatile) or stable feedback conditions, a phenomenon termed learning rate adaptation; and (3) reduced learning rate adaptation is associated with several psychiatric disorders. In other words, multiple learning rate parameters are needed to account for behavioral differences across participant populations and volatility contexts in this flexible learning rate (FLR) model. Here, we propose an alternative explanation, suggesting that behavioral variation across participant populations and volatile contexts arises from the use of mixed decision strategies. To test this hypothesis, we constructed a mixture-of-strategies (MOS) model and used it to analyze the behaviors of 54 healthy controls and 32 patients with anxiety and depression in volatile reversal learning tasks. Compared to the FLR model, the MOS model can reproduce the three classic phenomena by using a single set of strategy preference parameters without introducing any learning rate differences. In addition, the MOS model can successfully account for several novel behavioral patterns that cannot be explained by the FLR model. Preferences for different strategies also predict individual variations in symptom severity. These findings underscore the importance of considering mixed strategy use in human learning and decision-making and suggest atypical strategy preference as a potential mechanism for learning deficits in psychiatric disorders.

Regulation of external electric field on sensitivity of ICM energetic materials.

CONTEXT: [2,2'-Bi(1,3,4-oxadiazole)]-5,5'-dinitramide (ICM-101), 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (ICM-102), and 6-nitro-7-azido-pyrazol[3,4-d][1,2,3]triazine-2-oxide (ICM-103) are excellent China-made explosives, but their performance under external electric fields (EEF) has never been explored, especially sensitivity. To study the induction effect of EEF on it, the chemical reactivity, electron localization function (ELF), spectrum, and other parameters were calculated by density functional theory. The results show that the increasing EEF can weaken the △EHOMO-LUMO (△EHOMO-LUMO = EHOMO-ELUMO) materials, making the stability worse and the sensitivity higher. The proportion of the positive electrostatic surface potential area is also smaller under the increasing EEF, indicating that ICM molecules are becoming more and more unstable. The ELF and localized orbital locator (LOL) decrease with the increase of EEF strength, which suggests that the trigger bond length increases, the EBDE decreases, and the molecular sensitivity increases. When the intensity of EEF increases, the absorption peak of the molecular spectrum gradually redshifts, and even a weak new absorption peak appears, indicating that the color of the material may change. Finally, EEF strength affects electron density, nitro charge, and chemical reactivity parameters. METHODS: Gaussian 16 software was used for calculation. The calculation levels are B3LYP/6-311G+ (d, p) and B3LYP/Def2-TZVPP. The optimized structure has a local true minimum energy on the potential energy surface and no imaginary frequency. Multiwfn 3.8 and VMD 1.9.3 were used in this work to analyze the ICM series of energetic material wave functions. The strength range of EEF is 0.000-0.016 a.u., and the increasing gradient is 0.002 a.u.

Molecular design and theoretical study of oxadiazole-bifurazan derivatives.

CONTEXT: The design and synthesis of new high energy density materials is an important part of the research in the field of high energy materials. However, the synthesis of high-energy materials is very difficult and dangerous. Therefore, it is necessary to design the compounds in advance and evaluate the performance of the designed compounds, so as to screen the high-energy candidate compounds with excellent performance and provide reference for future synthesis and application. 1,2,5-oxadiazole (furazan) and 1,2,4-oxadiazole are five-membered nitrogen-oxygen heterocycles. Because their structures contain high-energy N-O, C=N bonds, they can effectively improve the energy density and oxygen balance of compounds, which has attracted widespread attention. In this paper, 42 kinds of oxadiazole-bifurazan energetic derivatives were designed by inserting different functional groups and changing the parent bridging groups with 1,2,4-oxadiazole and furazan as the basic structural units. Their electronic structures, aromaticity, heats of formation (HOFs), detonation properties, thermodynamic properties and electrostatic potential were systematically studied by density functional than theory (DFT). The results show that -C (NO2)3 has the greatest improvement effect on HOFs among all the substituent groups. The detonation performance of -N=N- bridged oxadiazole-bifurazan derivatives is better than that of -NH-NH- bridged derivatives. And -C(NO2)3 is the most effective group to improve the detonation performance and density of compounds. Compared with the parent compounds, when a -C(NO2)3 was introduced, the density increased by about 5.5%. A6 (D = 10.30 km·s-1, P = 48.86 GPa) and D6 (D = 9.57 km·s-1, P = 42.31 GPa) are the compounds with the best D and P among the designed compounds, which are higher than RDX and HMX, and are potential candidates for new high-energy materials. METHODS: With the help of Gaussian16 software and Multiwfn 3.8 package, the B3LYP method in density functional theory was selected. The 6-311G (d, p) basis set was used to optimize the structure of the 42 derivatives, and the high-precision def2-TZVPP basis set was used to calculate the energy.

Structural transformation of methyl urotropine perchlorate under high pressure.

Based on the first-principles calculations of density functional theory (DFT), the crystal structure, molecular structure, electronic properties, and optical absorption properties of methyl urotropine perchlorate under hydrostatic compression in the range of 0 ~ 100 GPa were calculated. The results show that the crystal structure of methyl urotropine perchlorate undergoes two structural transformations under hydrostatic compression. The H1A-H1B bond breaks at 25 GPa, generating two new covalent bonds N3-H1A and O1-H1B. The covalent bonds of O2A-C1 and Cl1-H3A are formed at 85 GPa. The compression ratio of lattice constants (a, b, c) and unit cell volume change abruptly at 25 GPa and 85 GPa, respectively. The conclusion that new bonds are formed under high pressure is further demonstrated by analyzing the partial density of states (PDOS) of N3, H1A, O1, H1B, O2A, C1, Cl1, and H3A atoms. The absorption spectrum showed that the absorption peak of methyl urotropine perchlorate gradually enhanced with the increase of pressure and the highest absorption peak shifted to high frequency.

Regulation of external electric field on the high-energy polynitrogen compound 1,5-diaminotetrazole-4 N-oxide.

BACKGROUND: The external electric field (EEF) tends to have a significant impact on chemicals, especially energetic materials. METHODS: Molecular structure, electrostatic potential (ESP), electron density difference, density of states (DOS), and frontier molecular orbitals (FMOs) of 1,5-diaminotetrazole-4N-oxide (SYX-9) are calculated by density functional theory (DFT) at B3LYP/6-311G+(d, p) and M062X/def2-TZVP under external electric field. RESULTS: Calculated results reveal that EEF has definite influence on the trigger bond of SYX-9, especially in positive direction, and the shortening of the trigger bond caused by it can effectively reduce the sensitive of SYX-9. In addition, EEF has an effect on the electron density of SYX-9. The positive EEF can reduce the HOMO-LUMO gap. From the perspective of components of energy variation and the force on atoms, the factors of structural deformation are specifically investigated. The aromaticity of SYX-9 makes its structure stable under the influence of EEF, which is verified by the method of the iso-chemical shielding surface (ICSS).

Strong adsorption properties and mechanism of action with regard to tetracycline adsorption of double-network polyvinyl alcohol-copper alginate gel beads.

In the present study, glutaraldehyde was used as a hydrophobic modifier to crosslink polyvinyl alcohol (PVA), and copper ion was immobilized by sodium alginate (SA). Polyvinyl alcohol-copper alginate (PVA-CA) gel beads were prepared by a one-step process, and were used to adsorb and remove tetracycline (TC) from an aqueous solution. The beads were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) measurement, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR). The adsorption experiment showed that the optimal pH value of the beads was 5, and that their adsorption met pseudo-second-order kinetic and Langmuir isothermal models. The adsorption thermodynamics experiment showed that the adsorption process was spontaneous and endothermic. Under optimal adsorption conditions, the maximum adsorption capacity for TC of the beads was 231.431 mg/g, which was much higher than that of a single copper alginate matrix. After 5 adsorption-desorption cycles, the adsorption capacity remained high. FTIR and X-ray photoelectron spectroscopy (XPS) revealed that the cation bonding bridge reaction was the main driving force behind the adsorption mechanism. Compared with other reported adsorption materials, the PVA-CA gel beads have high adsorption capacity, a simple preparation process, and excellent recovery performance.

Effect of biochar on transformation of dissolved organic matter and DTPA-extractable Cu and Cd during sediment composting.

This study investigated the influence of biochar on temperature, pH, organic matter (OM), seed germination index (GI), the fluorescent components of dissolved organic matter (DOM), and bioavailability of DTPA-extractable Cu and Cd during composting and analyzed the relation between DTPA-extractable metals with pH, OM, and the fluorescent components of DOM. Results showed that the addition of biochar shortened the thermophilic phase, reduced the pH at maturation period, accelerated the decomposition of OM, and raised GI. Besides, it promoted the formation of components with benzene ring in FA and HyI and the degradation of protein-like organic-matters in FA and HA, which was mainly related with the decrease of DTPA-extractable Cd and the increase of DTPA-extractable Cu. After composting, DTPA-extractable Cd in pile A and pile B were decreased by 37.15% and 27.54%, respectively, while the bioavailability of Cu in pile A and pile B was increased by 65.71% and 68.70%, respectively. All these findings demonstrate positive and negative impact produced by biochar into various heavy metals and the necessary of optimization measures with biochar in sediment composting.

Effect of Autoinducer-2 Quorum Sensing Inhibitor on Interspecies Quorum Sensing.

Bacterial drug resistance caused by overuse and misuse of antibiotics is common, especially in clinical multispecies infections. It is of great significance to discover novel agents to treat clinical bacterial infections. Studies have demonstrated that autoinducer-2 (AI-2), a signal molecule in quorum sensing (QS), plays an important role in communication among multiple bacterial species and bacterial drug-resistance. Previously, 14 AI-2 inhibited compounds were selected through virtual screening by using the AI-2 receptor protein LuxP as a target. Here, we used Vibrio harveyi BB170 as a reporter strain for the preliminary screening of 14 inhibitors and compound Str7410 had higher AI-2 QS inhibition activity (IC50 = 0.3724 ± 0.1091 µM). Then, co-culture of Pseudomonas aeruginosa PAO1 with Staphylococcus aureus ATCC 25923 was used to evaluate the inhibitory effects of Str7410 on multispecies infection in vitro and in vivo. In vitro, Str7410 significantly inhibited the formation of mixed bacterial biofilms. Meanwhile, the combination of Str7410 with meropenem trihydrate (MEPM) significantly improved the susceptibility of mixed-species-biofilm cells to the antibiotic. In vivo, Str7410 significantly increased the survival rate of wild-type Caenorhabditis elegans N2 co-infected by P. aeruginosa PAO1 and S. aureus ATCC 25923. Real-time quantitative PCR analysis showed that Str7410 reduced virulence factor (pyocyanin and elastase) production and swarming motility of P. aeruginosa PAO1 by downregulating the expression of QS-related genes in strain PAO1 in co-culture with S. aureus ATCC 25923. Compound Str7410 is a candidate agent for treating drug-resistant multispecies infections. The work described here provides a strategy for discovering novel antibacterial drugs.

Lactobacillus buchneri S-layer protein-coated liposomes loaded with ß-cyclodextrin-carvacrol inclusion complexes for the enhancement of antibacterial effect.

This article describes the development of a novel liposome nanocarrier system. Carvacrol (Car) is first embedded in ß-cyclodextrin (ß-CD) by the freeze-drying method to form the ß-cyclodextrin-carvacrol inclusion compound (ß-CD-Car), and then ß-CD-Car liposomes (ß-CD-Car-LPs) and ß-CD-Car liposomes coated with S-layer proteins (SLPs) from Lactobacillus buchneri 20023 (SLP/ß-CD-Car-LPs) were prepared. The liposomes were characterized, and their stabilities, in vitro release characteristics, and antibacterial activities were investigated. Results showed that the fabricated liposome SLP/ß-CD-Car-LPs was nanosized, oval and homogenous, with the particle size of 229.1 ± 6.81 nm, the polydispersity index of 0.139, and the zeta potential of 27.9 mV. Measurements based on Triton X-100 resistance indicated that the SLP-coated liposomes were more stable than naked liposomes. The in vitro release study results showed that the rate of release from SLP-coated liposomes was much lower than that from uncoated liposomes. The minimum inhibitory activity (MIC) of SLP/ß-CD-Car-LPs (0.05 mg/mL) was 6.4 times higher than that of the free carvacrol (0.32 mg/mL) and was twice that of ß-CD-Car-LPs (0.1 mg/mL). In general, the stability, antibacterial activity, and sustained release effect of ß-CD-Car-LPs modified with SLPs were improved. Findings suggested that SLP-coated liposomes could be developed as a favorable delivery system for potential applications in the food industry.

Electrochemical, spectroscopic, and photophysical properties of structurally diverse polyazine-bridged Ru(II),Pt(II) and Os(II),Ru(II),Pt(II) supramolecular motifs.

Five new tetrametallic supramolecules of the motif [{(TL)(2)M(dpp)}(2)Ru(BL)PtCl(2)](6+) and three new trimetallic light absorbers [{(TL)(2)M(dpp)}(2)Ru(BL)](6+) (TL = bpy = 2,2'-bipyridine or phen = 1,10-phenanthroline; M = Ru(II) or Os(II); BL = dpp = 2,3-bis(2-pyridyl)pyrazine, dpq = 2,3-bis(2-pyridyl)quinoxaline, or bpm = 2,2'-bipyrimidine) were synthesized and their redox, spectroscopic, and photophysical properties investigated. The tetrametallic complexes couple a Pt(II)-based reactive metal center to Ru and/or Os light absorbers through two different polyazine BL to provide structural diversity and interesting resultant properties. The redox potential of the M(II/III) couple is modulated by M variation, with the terminal Ru(II/III) occurring at 1.58-1.61 V and terminal Os(II/III) couples at 1.07-1.18 V versus Ag/AgCl. [{(TL)(2)M(dpp)}(2)Ru(BL)](PF(6))(6) display terminal M(dπ)-based highest occupied molecular orbitals (HOMOs) with the dpp(π*)-based lowest unoccupied molecular orbital (LUMO) energy relatively unaffected by the nature of BL. The coupling of Pt to the BL results in orbital inversion with localization of the LUMO on the remote BL in the tetrametallic complexes, providing a lowest energy charge separated (CS) state with an oxidized terminal Ru or Os and spatially separated reduced BL. The complexes [{(TL)(2)M(dpp)}(2)Ru(BL)](6+) and [{(TL)(2)M(dpp)}(2)Ru(BL)PtCl(2)](6+) efficiently absorb light throughout the UV and visible regions with intense metal-to-ligand charge transfer (MLCT) transitions in the visible at about 540 nm (M = Ru) and 560 nm (M = Os) (ε ≈ 33,000-42,000 M(-1) cm(-1)) and direct excitation to the spin-forbidden (3)MLCT excited state in the Os complexes about 720 nm. All the trimetallic and tetrametallic Ru-based supramolecular systems emit from the terminal Ru(dπ)→dpp(π*) (3)MLCT state, λ(max)(em) ≈ 750 nm. The tetrametallic systems display complex excited state dynamics with quenching of the (3)MLCT emission at room temperature to populate the lowest-lying (3)CS state population of the emissive (3)MLCT state.