Triad Complexes Research Articles

The effect of encapsulation of lithium atom on supramolecular triad complexes performance in solar cell by using theoretical approach

Solar energy is the most important type of modern and renewable energies. If it displaces fossil fuels, can bring an end to concerns about finiteness of fuels, environmental pollution caused by fossil fuels, price fluctuations and energy crisis. Among the energy sources, due to the high potential of solar energies in wide areas of the world, it has great importance to researchers. Dye-sensitized solar cells (DSSCs) representation one of the most hopefully is appearing technologies for sunlight-to-electrical energy transformation. In the present research density functional theory and time-dependent semiempirical ZINDO/S (TD-ZINDO/S) methods have been used to investigate two series of triad system containing fullerene, porphyrin (P), and metalloporphyrin (Mp) as a dye sensitizer. In the first series, C60–porphyrin–metalloporphyrin (C60–P–Mp) triad system with M being Mg, Sc, Ti, Mn, Fe, Co, and Zn was investigated and in the second series, Li@C60 replaced with C60 (Li@C60–P–Mp). The influences of the type of metal in the P ring, and insertion of Li in the C60 on the energies of frontier molecular orbital and UV–Vis spectra have been studied. Structural optimizations of triad systems are carried out using the SIESTA package of program and the energy levels and electron density of the highest occupied molecular orbital and the lowest unoccupied molecular orbital, chemical hardness (η), electrophilicity index (ω), and electron accepting power (ω +). Moreover, the light harvesting efficiency was calculated by means of the oscillator strengths, which are obtained by TD-ZINDO/S calculation. Calculation results showed that three complexes Li@C60–P–ScP, Li@C60–P–CoP, Li@C60–P–MnP with low energy gap make these potential triad complexes in photovoltaic applications and are also excellent efficient as DSSC.

Is there theoretical evidence for mutual influence between halogen and pnicogen-hydride bonds? An ab initio study

Ab initio MP2 /6-311 ++G(d,p) level calculations have been carried out to investigate the interplay between the halogen and pnicogen-hydride bonds in NCX ⋯OPH 3⋯HMgY complexes (X = F, Cl, Br; Y = F, Cl, Br, H). The results indicated that the cooperative effects are obvious in the target complexes. These effects were considered in detail in terms of electrostatic potential, energetic, geometric, charge-transfer and electron density properties of the complexes. The values of cooperative energy (Ecoop) were ranging from −0.41 to −0.60 kJ /mol, −1.02 to −1.57 kJ /mol and −1.50 to −2.28 kJ /mol for X = F, Cl and Br, respectively. Based on many-body analysis, two and three-body terms of interaction energies have a positive contribution to the total interaction energy. It was found that the amount of charge transfer in the triads is higher than that in the corresponding dyads. AIM analyses showed that the halogen and pnicogen-hydride bonds in the triads are amplified with respect to the dyads. Mutual influence between the halogen and pnicogen-hydride bonds is investigated by ab initio calculations. Cooperative effects were observed in the dyad and triad complexes in which halogen and pnicogen-hydride bonds coexist.

The relationship between electrospray ionization behavior and cytotoxic activity of [MI(P)4]+‐type complexes (M = Cu, Ag and Au; P = tertiary phosphine)

To try to find a correlation between the antiproliferative activity of a series of [M(I)(P)4](+) complexes (M = Cu, Ag and Au; P = tertiary phosphine) and their stability at micromolar concentration under mass spectrometric conditions. [M(I)(P)4](+) complexes were investigated by positive ion electrospray ionization mass spectrometry with multiple collisional experiments using an ion trap mass spectrometer. The displacement of P from native [M(I)(P)4](+), previously described for the copper derivative, is common for the triad complexes leading to the formation of [M(P)3](+) and [M(P)2](+) adducts. Further dissociation of [M(P)2](+) depends on the nature of the metal (Cu ~ Ag > Au). More labile [Cu(P)2](+) and [Ag(P)2](+) are more cytotoxic against HCT-15 human colon carcinoma cells compared to less labile [Au(P)2](+) species. The dissociation of P ligand(s) from the [M(I)(P)4](+) complexes is the driving force for the triggering of the antiproliferative activity. The more favored is the displacement of P from the [M(P)2](+) active form, the more favored is in turn the possibility for the metal to interact with biological substrates related to cancer proliferation.

σ-Bond Metathesis between M–X and RC(O)X′ (M = Pt, Pd; X, X′ = Cl, Br, I): Facile Determination of the Relative ΔG Values of the Oxidative Additions of RC(O)X to an M(0) Complex, Evidence by Density Functional Theory Calculations, and Synthetic Applications

The novel utility of the ligand exchange reaction between M–X and RC(O)X′ (X, X′ = halogen; R = aryl, alkyl) is described. The relative ΔGs (ΔΔGs) of the oxidative additions of acid halides RC(O)X to M(PPh3)2Ln (M = Pt, Pd) were determined using the halogen-exchange reactions between X of trans-M(X)[C(O)R](PPh3)2 and X′ of RC(O)X′. Experimental thermodynamics data are reasonably consistent with those obtained by density functional theory (DFT) calculations. Activation parameters obtained by experiments as well as a systematic DFT study supported the fact that reactions occurred through slightly distorted quadrangular pentacoordinated σ-bond metatheses, in which the Cl atom underwent a more indirect course than the Br atom. Moreover, exchange reactions were employed as the accessible prototype for the conversion of halogen ligands of nickel triad complexes into heavier halogen ligands.

Interfragment transmission of electronic effects of π-acceptor ligands in heterometallic triad complexes with trans-[Ru(Py)4(CN)2] as a central unit

The complex trans-[RuPy4(CN)2] cleaves chloride bridges in the binuclear rhodium(i) and palladium(ii) complexes [Rh(CO)2Cl]2, [Rh(η4-C8H12)Cl]2, [(η4-C8H12)Rh(μ-Cl)2Rh(CO)2], [Pd(η3-C3H5)Cl]2, and [(η3-C3H5)Pd(μ-Cl)2Rh(CO)2] to form heterometallic triad complexes [(CO)2ClRh(NC)RuPy4(CN)RhCl(CO)2] (1), [(η4-C8H12)ClRh(NC)RuPy4(CN)RhCl-(η4-C8H12)] (2), [(CO)2ClRh(NC)RuPy4(CN)RhCl(η4-C8H12)] (3), [(η3-C3H5)ClPd(NC)-Ru(Py)4(CN)PdCl(η3-C3H5)] (4), and [(CO)2ClRh(NC)Ru(Py)4(CN)PdCl(η3-C3H5)] (5), respectively. In solutions, complex 3 coexists with equilibrium amounts of compounds 1 and 2; complex 5 is in the equilibrium with compounds 4 and 1. In both cases, the ratio of concentrations is close to binomial. Complexes 2 and 5 treated with [Rh(CO)2Cl]2 are converted into 1 with the simultaneous formation of [Rh(η4-C8H12)Cl]2 and [Pd(η3-C3H5)Cl]2, respectively. The δH and δC values for the ligands η4-C8H12, η3-C3H5, and CO are sensitive to the nature of the remote triad unit. The ligand effects are shown to be transmitted along the chain L′-M′-(NC)-Ru-(CN)-M″-L″.

Binuclear rhodium organometallic complexes as catalysts of the liquid-phase 1-octene oxidation

The reaction of catalytic liquid-phase oxidation of olefins by molecular oxygen belongs to the most promising processes of organic synthesis and is a subject of numerous publications (see [1–3] for example). We have shown recently [4] that mononuclear rhodium organometallic complexes are active catalysts of the 1-octene oxidation by molecular oxygen. In this communication we present preliminary results of studying catalytic properties of complexes containing several metal centers, namely binuclear complexes of rhodium (+1), rhodium (+3), iridium (+1), palladium (+2), and triad complexes containing the ruthenium (+2) complex trans-[Ru(py)4(CN)2] as a central unit and rhodium (+1) or palladium (+2) complexes as terminal fragments.

Application of acetone cyanohydrin in the synthesis of cyanide complexes of transition metals

In the work [1] we have described the triad complexes [(CO)2ClRh(NC)RuPy4(CN)RhCl(CO)2], [(Cod)ClRh(NC)RuPy4(CN)RhCl(Cod)], and [(Cod)· ClRh(NC)RuPy4(CN)RhCl(CO)2] with ruthenium(II) complex trans-[RuPy4(CN)2] (I) (Py is pyridine) as a central unit [2]. The desire to avoid inconveniences caused by the use of high-toxic KCN has resulted in our attempt to apply acetone cyanohydrin, (CH3)2C· (OH)(CN), as a source of cyanide ions in the synthesis of complex I. Testing this reagent in the cyanide process of gold oxidative dissolution has given encouraging results in due time [3]. We have obtained complex I with a satisfactory yield in experiments with application of a water–alkaline solution of acetone cyanohydrin instead of potassium cyanide.

Heterometallic cyanide-bridged complexes containing Rh IRu IIRh I triad: NMR data on exchange reactions and ligand effect transmission

Trans-[RuPy 4(CN) 2 cleaves chloro-rhodium bridges in rhodium(I) binuclear complexes, [Rh(CO) 2Cl] 2, [Rh(Cod)Cl] 2, and [(Cod)RhCl 2Rh(CO) 2] yielding heterometallic triad complexes, [(CO) 2ClRh(NC)RuPy 4(CN)RhCl(CO) 2] ( I), [(Cod)ClRh(NC)RuPy 4(CN)RhCl(Cod)] ( II), and [(Cod)ClRh(NC)RuPy 4(CN)RhCl(CO) 2] ( III), respectively. In solutions, III coexists with equilibrium amounts of I and II in the near-binomial proportions. Under action of [Rh(CO) 2Cl] 2, II transforms into I with parallel formation of [Rh(Cod)Cl] 2. Ligand effect transmission along the L-Rh-NC-Ru-CN-Rh-L′ chain is studied by 1H and 13C NMR. Chemical shifts δ 1H and δ 13C of Ru-bound Py ligands are sensitive to the nature of Rh-bound ligands. Values of δ 1H and δ 13C of Cod and 13C of CO ligands are sensitive to the ligands at the remote end of the L-Rh-NC-Ru-CN-Rh-L′ chain. Reaction of trans-[RuPy 4(CN) 2] with Rh 2(OAc) 4 yields an apparently linear polymer [-Rh(OAc) 4Rh-NCRuPy 4CN-]. Upon action of [Rh(CO) 2Cl] 2, the polymer decomposes yielding I and Rh 2(OAc) 4. X-ray structure data for I are given.

Investigation of Group 12 Metal Complexes with a Tridentate SNS Ligand by X-ray Crystallography and 1H NMR Spectroscopy

Two series of zinc triad complexes containing the ligand 2,6-bis(methylthiomethyl)pyridine (L1) were synthesized and characterized by X-ray crystallography and solution-state 1H NMR spectroscopy. The distorted meridional octahedral M(L1)2(ClO4)2 series includes the first structurally characterized Zn(II) and Cd(II) complexes with N2(SR2)4 coordination spheres. Coordination of HgCl2 and ZnCl2 with 1 equiv of ligand afforded mononuclear, five-coordinate species Hg(L1)Cl2 and Zn(L1)Cl2, respectively, with distorted square-pyramidal and trigonal-bipyramidal geometries. With CdCl2, the dimeric [Cd(L1)Cl(mu-Cl)]2 complex was obtained. The distorted octahedral coordination geometry of each Cd(II) center in this complex is formed by one tridentate ligand, two bridging chloride ions, and one terminal chloride ion. NMR spectra indicate that the intermolecular ligand-exchange rate of [M(L1)2](2+) decreased in the order Cd(II) > Zn(II) > Hg(II). Slow intermolecular ligand-exchange conditions on the chemical-shift time scale were found for 1:2 metal-to-ligand complexes of L(1) with Hg(II) and Zn(II) but not Cd(II). Slow intermolecular ligand-exchange conditions in acetonitrile-d(3) solutions permitting detection of (3-5)J(199Hg1H) were found for 1:1 and 1:2 Hg(ClO4)2/L1 complexes, but not for the related Cd(ClO4)2) complexes. The magnitudes of J(199Hg1H) for equivalent protons were smaller in [Hg(L1)2](2+) than in [Hg(L1)(NCCH3)x](2+). The relative intermolecular ligand-exchange rates of the zinc triad complexes investigated here suggest that the toxicity of Hg(II) is accentuated by the relative difficulty of displacing it from the coordination sites encountered.

The effect of extracellular tonicity on the anatomy of triad complexes in amphibian skeletal muscle.

Ultrastructural features of tubular-sarcoplasmic (T-SR) triad junctions and measures of cell volume following graded increases of extracellular tonicity were compared under physiological conditions recently shown to produce spontaneous release of intracellularly stored Ca2+ in fully polarized amphibian skeletal muscle fibres. The fibres were fixed using solutions of equivalent tonicities prior to processing for electron microscopy. The resulting anatomical sections demonstrated a partially reversible cell shrinkage corresponding to substantial increases in intracellular solute or ionic strength graded with extracellular tonicity. Serial thin sections through triad structures confirmed the presence of geometrically close but anatomically isolated transverse (T-) tubular and sarcoplasmic reticular (SR) membranes contrary to earlier suggestions for the development of luminal continuities between these structures in hypertonic solutions. They also quantitatively demonstrated accompanying decreases in T-SR distances, increased numbers of sections that showed closely apposed T and SR membranes, tubular luminal swelling and reductions in luminal volume of the junctional SR, all correlated with the imposed increases in extracellular osmolarity. Fully polarized fibres correspondingly showed elementary Ca(2+)-release events ('sparks', in 100 mM-sucrose-Ringer solution), sustained Ca2+ elevations and propagated Ca2+ waves (> or = 350-500 mM sucrose) following exposure to physiological Ringer solutions of successively greater tonicities. These were absent in hypotonic, isotonic or less strongly hypertonic (approximately 50 mM sucrose-Ringer) solutions. Yet exposure to hypotonic solutions also disrupted T-SR junctional anatomy. It increased the tubular diameters and T-SR distances and reduced their area of potential contact. The spontaneous release of intracellularly stored Ca2+ thus appears more closely to correlate with the expected changes in intracellular solute strength or a reduction in absolute T-SR distance rather than disruption of an optimal anatomical relationship between T and SR membranes taking place with either increases or decreases in extracellular tonicity.

Syntheses, Spectroelectrochemistry and Photoinduced Electron-Transfer Processes of Novel Ru and Os Dyad and Triad Complexes with Functionalized Diimide Ligands

A series of mono- and dinuclear Ru complexes containing a bridging ligand, L-diimide-L (L = 2-(2-pyridyl)benzimidazole; diimide = benzene-1,2:4,5-bis(dicarboximide) (bdi; pyromellitimide) or naphthalene-1,8:4,5-bis(dicarboximide) (ndi), with either propane or xylene group as linkers, have been prepared. The mono- and dinuclear Ru complexes containing the bdi or ndi ligand, exhibit characteristic metal-to-ligand charge transfer (MLCT) transition at 458 nm. The mono- and dinuclear Ru/Os complexes exhibit a rich redox chemistry arising from both M(II) to M(III) oxidation and ligand-based consecutive reduction of diimide and 2,2'-bipyridine (bpy) ligands. The emission decays fit well with double- or triple-exponential decay models. The non-exponential decay curve reveals the existence of several conformers in solution due to the flexible propane or p-xylene linker. The much shorter emission lifetimes of the [M(bpy)2(L-diimide-L)] complexes compared with the parent [M(bpy)2L] indicates the intramolecular electron-transfer from the excited M(bpy)2 moiety to the diimide. The fastest rates of electron transfer (3 · 1010 s-1) are attributable to the folded conformers suitable for the electron donor/acceptor through-space interaction. A time-resolved absorption spectroscopic study of the dinuclear bdi and ndi complexes revealed appearance of the electron-transfer products, M(III) and the diimide radical anion, and their rapid disappearance. The effect of the linkers of the ligand L-diimide-L on the rates of electron transfer and the back electron transfer is also discussed.

Effects of chronic low-frequency stimulation on Ca2+-regulatory membrane proteins in rabbit fast muscle.

Since chronic low-frequency stimulation of fast-twitch muscle fibers has a profound effect on all major functional elements of skeletal muscle, we analyzed the potential changes in the levels of Ca2+-regulatory membrane proteins during fast-to-slow transformation. In this study we show that, in addition to isoform-switching in myosin heavy chains, electrostimulation triggers a decline in fast isoforms and an increase in slow/cardiac isoforms of Ca2+-ATPase and calsequestrin. The levels of excitation-contraction coupling elements, such as the ryanodine receptor, the dihydropyridine receptor, triadin and sarcalumenin, decreased sharply following stimulation. In contrast, levels of Na+/K+-ATPase and calreticulin increased in the microsomal fraction. Crosslinking studies have revealed that in normal and stimulated muscle the Ca2+-ATPase isoforms exist predominantly as oligomeric structures, and that the central elements of excitation-contraction coupling also form large triad complexes. Changes in the levels and pattern of isoform expression of the muscle membrane proteins studied here suggest that these biochemical alterations reflect molecular adaptations to changed demands in ion homeostasis and signal transduction in muscle that exhibits enhanced contractile activity. Overall, these findings support the physiological concept that there are muscle fiber-type specific differences in the fine-tuning of the excitation-contraction-relaxation cycle, as well as the idea that mature skeletal muscle fibers exhibit a high degree of plasticity.

Molecular complexes based on tetrapyrrole compounds. Quantum-chemical investigation of the properties of excited states and conformational dynamics

On the basis of quantum-chemical calculations of the properties of excited states and comparison with the experimental data, we show that at room temperature unliganded dimers of Zn-porphyrins and Zn-chlorins, bonded through a CH2−CH2-group, are in a conformation close to an eclipsed one, while their dipyridine complexes are in an unchanged conformation. For triad and pentad complexes, formed as a result of extraliganding of dimers of Zn-porphyrins with di- and tetrapyridyl-substituted free bases of porphyrins, the calculations predict the presence of states with transfer of a charge from dimers onto a free porphyrin base that are manifested in the region between the Q- and B-transitions in electron absorption spectra.

Synthesis of, Characterization of, and Photoinduced Processes in Polymetallic Triad Complexes Containing Fe(II), Ru(II), and Rh(III) Metal Centers

A series of new trimetallic mixed complexes containing Fe(II), Ru(II), and Rh(III) metal centers have been prepared and characterized, and their excited-state properties in a nanosecond time domain have been investigated. These new compounds were synthesized by following a “building block” strategy from monomeric Rh(III) and Ru(II) polyazines and tetracyanoferrate(II) ions. The products generated in each synthetic step were fully characterized and their excited-state properties investigated. These new trimetallic complexes, [(CN)4FeII(BL(1))RuII(bpy)(BL(2))RhIII(tpy)(MQ+)](PF6)4 (tpy = 2,2‘:6‘:2‘‘-terpyridine; BL(1) = 2,3-bis(2-pyridyl)pyrazine (dpp) or 2,2‘-bipyrimidine (bpm); BL(2) = dpp or bpm; MQ+ = N-methyl-4,4‘-bipyridinium (monoquat)), consist of three fundamental parts linked by bridging ligands (i) an electron donor group, the tetracyanoferrate(II) unit; (ii) an antenna fragment, the Ru(II) polypyridyl moiety; and (iii) an electron acceptor group. The electron acceptor group is a Rh(III) polypyridyl that contains the ligands tpy and MQ+. No emission was observed in any of the reported complexes either in fluid solutions at room temperature or in glassy solutions at 77 K. Time-resolved experiments conducted on these triads showed formation of a transient intermediate within the laser pulse. Redox properties and transient absorption observations helped us to identify the nature of this intermediate as an Fe(III)/Ru(II) mixed-valence species that decays exponentially by following a first-order law with a lifetime of τ ≤ 70 ns in fluid solution at room temperature.

Synthesis and Photoinduced Electron Transfer Processes in Ru(II)(bpy)2/Os(III)(bpy)2-Based Triad Complexes Containing Functionalized Diimide Ligands

Abstract The charge separated(CS) state was efficiently formed as a result of stepwise electron transfer reactions in a novel Ru(II)(bpy)2-diimide-Os(III)(bpy)2 triad system (efficiency > 0.7); the rate of electron transfer and the charge separation yield were determined from picosecond time-resolved absorption spectra.

Reactions of cyclobutenedione and cyclopentenetrione with zero-valent nickel triad complexes of isocyanide. X-Ray crystal structures of (3–4-η-3,4-diphenylcyclobut-3-ene-1,2-dione)- and (4–5-η-4,5-diphenylcyclopent-4-ene-1,2,3-trione)-tris(t-butyl isocyanide)nickel

Hg[{Pt3(2,6-Me2C6H3NC)6}2] reacts with 3,4-diphenylcyclobut-3-ene-1,2-dione, (1), to give the 4,5-diphenylplatinacyclopent-4-ene-2,3-dione complex, (3a). Reactions of (1) and 4,5-diphenyl-cyclopent-4-ene-1,2,3-trione, (2), with [Pd3(RNC)6] or [Ni(RNC)4] give the olefinic complexes [Pd(2,6-Me2C6H3NC)2{(Ph[graphic omitted]O}](4a), [Pd(RNC)2Ph[graphic omitted]O}][R = 2,6-Me2C6H3(6a) or But(6c)], [Ni(RNC)3{Ph[graphic omitted]O}][R = 2,6-Me2C6H3(5a) or But(5c)], and [Ni(RNC)3{Ph[graphic omitted]O}][R = 2,6-Me2C6H3(7a) or But(7c)]. The structures of (5c) and (7c) have been established by single-crystal X-ray analysis: both crystals are monoclinic, space group P21/c, with Z= 4 in a unit cell of dimensions a= 13.027(7), b= 18.255(9), c= 17.727(9)A and β= 128.67(8)° for (5c) and a= 19.679(13), b= 16.499(11), c= 11.694(8)A, and β= 106.14(7)° for (7c).

ChemInform Abstract: SYNTHESIS WITH ELECTRON‐RICH NICKEL TRIAD COMPLEXES

Chemischer InformationsdienstVolume 12, Issue 1 Reviews ChemInform Abstract: SYNTHESIS WITH ELECTRON-RICH NICKEL TRIAD COMPLEXES E. UHLIG, E. UHLIGSearch for more papers by this authorD. WALTHER, D. WALTHERSearch for more papers by this author E. UHLIG, E. UHLIGSearch for more papers by this authorD. WALTHER, D. WALTHERSearch for more papers by this author First published: January 6, 1981 https://doi.org/10.1002/chin.198101369AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue1January 6, 1981 RelatedInformation

Synthesis with electron-rich nickel triad complexes

Synthesis with electron-rich nickel triad complexes

Stereoelectronic modulation of dioxygen coordination

Abstract

Additions and Corrections: Metal-Metal Bonding in Nickel Triad Complexes. The X-Ray Crystal Structure of a Platinum (II) Compound Pt2(S2CC6H4C3H7)4 Containing a Platinum-Platinum Bond

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdditions and Corrections: Metal-Metal Bonding in Nickel Triad Complexes. The X-Ray Crystal Structure of a Platinum (II) Compound Pt2(S2CC6H4C3H7)4 Containing a Platinum-Platinum BondJohn Fackler, Jr.Cite this: J. Am. Chem. Soc. 1972, 94, 7, 2558Publication Date (Print):April 1, 1972Publication History Published online8 July 2003Published inissue 1 April 1972https://doi.org/10.1021/ja00762a607RIGHTS & PERMISSIONSArticle Views19Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (166 KB) Get e-Alerts Get e-Alerts