Transition Metal Derivatives Research Articles

Deciphering Sodium-Ion Storage: 2D-Sulfide versus Oxide Through Experimental and Computational Analyses.

Transition metal derivatives exhibit high theoretical capacity, making them promising anode materials for sodium-ion batteries. Sulfides, known for their superior electrical conductivity compared to oxides, enhance charge transfer, leading to improved electrochemical performance. Here, a hierarchical WS2 micro-flower is synthesized by thermal sulfurization of WO3. Comprising interconnected thin nanosheets, this structure offers increased surface area, facilitating extensive internal surfaces for electrochemical redox reactions. The WS2 micro-flower demonstrates a specific capacity of ≈334mAhg-1 at 15mAg-1, nearly three times higher than its oxide counterpart. Further, it shows very stable performance as a high-temperature (65°C) anode with ≈180mAhg-1 reversible capacity at 100mAg-1 current rate. Post-cycling analysis confirms unchanged morphology, highlighting the structural stability and robustness of WS2. DFT calculations show that the electronic bandgap in both WS2 and WO3 increases when going from the bulk to monolayers. Na adsorption calculations show that Na atoms bind strongly in WO3 with a higher energy diffusion barrier when compared to WS2, corroborating the experimental findings. This study presents a significant insight into electrode material selection for sodium-ion storage applications.

Halide-free CO2 cycloaddition onto styrene oxide catalysed by first row transition-metal derivatives of polyoxotungstates.

Quaternary ammonium salts of metal derivatives of polyoxometalates [XW11O39M(H2O)]n- (X = P, Si; M = Cr, Mn, Co, Ni, Zn) were successfully tested instead of quaternary ammonium halides as catalysts in the cycloaddition of CO2 to styrene oxide. Remarkably, they gave very satisfactory yields of styrene carbonate at moderate temperature (80 °C).

Synthesis and characterization of two piperazine containing macrocycles and their transition metal complexes

Rigidification of the ligand scaffolds has been a particular mechanism of interest employed to achieve properties suitable for MRI contrast, catalysis, or other applications of metal complexes. Towards the goal of targeting a 15-anePyN5Pip type ligand, a serendipitous isolation of a 30-anePy2N10Pip2 aza-macrocycle was achieved, instead. X-ray diffraction and determination of pKa events were carried out and compared to 17-anePyN5Pip. Furthermore, the X-ray diffraction of the Cu(II) and Zn(II) complexes of 17-anePyN5Pip was achieved and compared to previous reports of other first-row transition metal derivatives of this ligand. Determination of the log β with both 30-anePy2N10Pip2 and 17-anePyN5Pip with the divalent MnZn metal-ion series was used to demonstrate the impact that the piperazine ring plays compared to other, less rigid macrocycles reported to date.

Research progress on MOFs and their derivatives as promising and efficient electrode materials for electrocatalytic hydrogen production from water.

Hydrogen energy is considered to be the most potential "ultimate energy source" due to its high combustion calorific value, cleanliness, and pollution-free characteristics. Furthermore, the production of hydrogen via the electrolysis of water has the advantages of simplicity, high efficiency, environmentally safe, and high-purity hydrogen. However, it is also associated with issues such as high-power consumption for the reaction and limited large-scale application of noble metal catalysts. Metal-organic frameworks (MOFs) are porous composite materials composed of metal ions and organic functional groups through orderly coordination with large specific surface areas and large porosity. Herein, we focus on the research status of MOFs and their transition metal derivatives for electrocatalytic water splitting to produce hydrogen and briefly describe the reaction mechanism and evaluation parameters of the electrocatalytic hydrogen evolution and oxygen evolution reactions. Furthermore, the relationship between the catalytic behavior and catalytic activity of different MOF-based catalysts and their morphology, elemental composition, and synthetic strategy is analyzed and discussed. The reasons for the excellent activity and poor stability of the original MOF materials for the electrolysis of water reaction are shown through analysis, and using various means to improve the catalytic activity by changing the electronic structure, active sites, and charge transfer rate, MOF-based catalysts were obtained. Finally, we present perspectives on the future development of MOFs for the electrocatalytic decomposition of water.

Rearrangement of a Ge(II) aryloxide to yield a new Ge(II) oxo-cluster [Ge6(μ3-O)4(μ2-OC6H2-2,4,6-Cy3)4](NH3)0.5: main group aryloxides of Ge(II), Sn(II), and Pb(II) [M(OC6H2-2,4,6-Cy3)2]2 (Cy = cyclohexyl).

The new Ge(II) cluster [Ge6(μ3-O)4(μ2-OC6H2-2,4,6-Cy3)4](NH3)0.5 (1) and three divalent Group 14 aryloxide derivatives [Ge(OC6H2-2,4,6-Cy3)2]2 (2), [Sn(OC6H2-2,4,6-Cy3)2]2 (3), and [Pb(OC6H2-2,4,6-Cy3)2]2 (4) of the new tricyclohexylphenyloxo ligand, [(-OC6H2-2,4,6-Cy3)2]2 (Cy = cyclohexyl), were synthesized and characterized. Complexes 1-4 were obtained by reaction of the metal bissilylamides M(N(SiMe3)2)2 (M = Ge, Sn, Pb) with 2,4,6-tricyclohexylphenol in hexane at room temperature. If the freshly generated reaction mixture for the synthesis of 2 is stirred in solution for 12 h at room temperature, the cluster [Ge6(μ3-O)4(μ2-OC6H2-2,4,6-Cy3)4](NH3)0.5 (1), which features a rare Ge6O8 core that includes ammonia molecules in non-coordinating positions, is formed. Complexes 3 and 4 were also characterized via119Sn{1H} NMR and 207Pb NMR spectroscopy and feature signals at -280.3 ppm (119Sn{1H}, 25 °C) and 1541.0 ppm (207Pb, 37 °C), respectively. The spectroscopic characterization of 3 and 4 extends known 119Sn parameters for dimeric Sn(II) aryloxides, but data for 207Pb NMR spectra for Pb(II) aryloxides are rare. We present also a rare VT-NMR study of a homoleptic 3-coordinate Pb(II) aryloxide. The crystal structures of 2, 3, and 4 feature interligand H⋯H contacts that are similar in number to those of related transition metal derivatives despite the larger size of the group 14 elements.

Electrochemistry of Innocent and Noninnocent Metallocorroles

Our laboratories have long been interested in the redox properties of four-, five- and six-coordinate metallocorroles (Chart 1) with different donor axial ligands and a variety of peripheral corrole substituents. In this work, we describe and compare our most recent results on different transition metal derivatives containing highly electron withdrawing substituents at the meso-positions of the macrocycle. Figure 1

Metallocene and other transition metal derivatives of phosphazene oligomers and polymers: A retrospective summary

Phosphazene rings and polymer chains possess a skeleton of alternating phosphorus and nitrogen atoms with two substituents linked to every phosphorus. Most of the known examples have organic or organosilicon side groups, but an increasing number have transition metal organometallic side units. Polymeric organometallic systems are of interest for the immobilization of catalysts or as electronic or optical materials and polymers with unique physical and engineering properties. Small molecule derivatives are valuable models for the synthesis of polymers and for understanding structural aspects. However, conversion of the small molecule information to the synthesis of metal-containing polymers is a major challenge. This brief account focuses on the linkage of metallocenes to the phosphazene platform and reviews some of the options available for access to other phosphazene-organometallic systems. It also emphasizes the importance of fluorophosphazenes in the development of organometallic derivatives. • Polymeric and small molecule phosphazenes are useful carrier molecules for transition metal compounds. • Metallocenyl side groups provide access to a range of electroactive or catalytic phosphazene derivatives. • Metal carbonyl clusters can be immobilized by coordination to the phosphazene skeletal system. • Skeletal or side group nitrogen atoms serve as linkage sites for platinum anti-tumor derivatives and for photoluminescent or Fe(II) spin crossover units.

Cation modulation in dual-phase nickel sulfide nanospheres by pulsed laser irradiation for overall water splitting and methanol oxidation reaction

The development of a non-precious and highly active multifunctional electrocatalyst is essential for obtaining efficient electrochemical energy storage and conversion devices. Nickel derivate occupies the most important place when it comes to the transition metal-based electrocatalyst. In this study, we used a simple and extremely effective controllable pulsed laser irradiation (PLI) technique to fabricate dual-phase nickel sulfide, and we studied cation modulation using Co and Cu atoms. The multifunctional activity was witnessed by the performances of oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and methanol oxidation reaction (MOR) measured in an alkaline medium. The cation adjustment resulted in the improvement of the catalytic performance of HER and OER during Cu and Co substitution, respectively. For the Co-Ni-S sample in OER, we achieved an overpotential of 368 mV at 10 mA/cm2 in OER. The higher ECSA Cu-Ni-S sample improved HER activity at a lower overpotential of 271 mV at 10 mA/cm2 and a lower Tafel slope of 98 mV/dec. The excellent bifunctional activity enhanced overall water splitting with a lower voltage of 1.88 V to achieve a geometrical current density of 10 mA/cm2, with high durability. Meanwhile, the high selectivity of Cu resulted in a very high methanol electrooxidation activity with a current density as high as 55.4 mA/cm2. The detailed electrochemical studies were presented with their supporting physiochemical analysis. This report shows the efficiency and simplicity of fabricating transition metal derivatives and cation modulation using superficial laser methods.

Synthesis, structure and properties of three novel transition-metal-containing tantalum-phosphate clusters

Peroxide ligation of aqueous metal–oxo clusters provides rich speciation and structural diversity. Here, three novel transition-metal derivatives of polyoxometalate anions, [Ni2(H2O)10{P4Ta6(O2)6O24}]6– (1a), [Zn(H2O)4{P4Ta6(O2)6O24}]8– (2a) and [Cd(H2O)4{P4Ta6(O2)6O24}]8– (3a), have been successfully synthesized by adopting a one-pot reaction strategy. All of these hexatantalates are built from a new-type phosphorus-incorporated hexatantalates. We investigated the solution behaviors, and the peak assignments of the MS spectra indicated some degree of stability of them in water. Furthermore, the proton-conducting ability of compound 1a was also explored and it has shown well conductivity at high relative humidities, with conductivity achieved 1.22 × 10–3 S/cm (85 °C, 90%RH).

Thiosemicarbazone derivatives of transition metals as multi-target drugs: A review

The mutations of bacteria and viruses along with the resistance of various targets to the existing drugs have emerged as great challenges in the medical field. This imposes the need for novel drugs and medicines to resolve such threats. Metal complexes with thiosemicarbazone (TSC) ligands and their derivatives have been reported to show good medicinal values and appear to be beneficial in terms of producing less toxic and more effective drugs. Literature survey shows that the metals have selectivity for the target cells and their coordination influences the binding of the ligand with proteins and enzymes. The present article gives an insight into the importance of coordination of TSCs with transition and inner transition metals. It also correlates the variation in the biological activities with the nature of metal bound to the TSC moiety and the presence of substituents attached to the parent TSC. Various explored derivatives of biologically active TSC – metal complexes have been reviewed. This paper has reviwed the enhancement in the biological activity of different classes of metal- TSC derivative complexes compared to their precursors. The authors have tried to correlate the synergic effect exhibited by metal TSC complexes and explored their future use as combination drugs.

An integrated approach to construct tantalum derivatives for electrocatalysis beyond the triiodide reduction reaction

The counter electrode (CE) is an essential component in dye-sensitized solar cells (DSSCs) to transfer electrons and catalyze triiodide reduction. In this research, efficient and cost-effective tantalum derivatives (oxide, nitride, carbide, oxynitride, and corresponding hybrids) are synthesized and utilized as CEs in DSSCs toward the triiodide reduction. The DSSC with mixed-anionic TaON CE achieves a cell efficiency of 5.46%, surpassing that with pristine TaOx CE (5.20%) before nitriding treatment. Benefiting from the synergistic interaction between mesoporous carbon (MC) and TaC0.95, TaC0.95/MC hybrid CE-based DSSC possess superior cell efficiency of 7.23%, higher than that of respective TaC (6.24%) and MC (6.52%), especially standard Pt (6.34%). Furthermore, TaON and TaC0.95/MC CEs exhibit durably great catalytic activity for I3- reduction. This work raises an effective and generally accepted approach to construct transition metal derivatives, which could utilize as low-priced Pt-free electrocatalysts for new energy devices.

Tris(Butadiene) Compounds versus Butadiene Oligomerization in Second-Row Transition Metal Chemistry: Effects of Increased Ligand Fields.

The geometries, energetics, and preferred spin states of the second-row transition metal tris(butadiene) complexes (C4H6)3M (M = Zr–Pd) and their isomers, including the experimentally known very stable molybdenum derivative (C4H6)3Mo, have been examined by density functional theory. Such low-energy structures are found to have low-spin singlet and doublet spin states in contrast to the corresponding derivatives of the first-row transition metals. The three butadiene ligands in the lowest-energy (C4H6)3M structures of the late second-row transition metals couple to form a C12H18 ligand that binds to the central metal atom as a hexahapto ligand for M = Pd but as an octahapto ligand for M = Rh and Ru. However, the lowest-energy (C4H6)3M structures of the early transition metals have three separate tetrahapto butadiene ligands for M = Zr, Nb, and Mo or two tetrahapto butadiene ligands and one dihapto butadiene ligand for M = Tc. The low energy of the experimentally known singlet (C4H6)3Mo structure contrasts with the very high energy of its experimentally unknown singlet chromium (C4H6)3Cr analog relative to quintet (C12H18)Cr isomers with an open-chain C12H18 ligand.

Agostic Hydrogens in 1‐Norbornyl Metal Cyclopentadienyl Structures

The first‐row transition metal 1‐norbornyl derivatives CpM(nor) Cp = η5‐C5H5; nor = 1‐norbornyl; M = Ti to Cu), including the experimentally known CpNi(nor) reported by Lehmkuhl and Dimitrov, have been examined by density functional theory and benchmarked by the more accurate DLPNO‐CCSD(T) method. The lowest energy CpM(nor) structures for the later first row transition metals from manganese to copper are found to be high‐spin state structures in which the 1‐norbornyl ligand is bonded to the metal only through the M–C σ‐bond to the bridgehead carbon atom. The favored spin states range from doublet for CpCu(nor) to sextet for CpMn(nor). The pattern of favorable structure types changes for the CpM(nor) derivatives of the earlier first row transition metals to the left of manganese since all of their low energy structures have singly or doubly agostic 1‐norbornyl groups. The agostic C–H–M interactions in the CpM(nor) derivatives are characterized by their reduced density gradients and low ν(C–H) frequencies.

Transition metal complexes of monodentate 2-oxazolines containing long chain alkyl groups. The crystal structure of trans-PdCl2(κ 1-N-rac-2-heptadecyl-4,5-dihydro-5-methyl-2-oxazole)2

Abstract The synthesis, characterisation and properties of several divalent metal complexes (Co, Ni, Pd) containing 2-oxazoline ligands L1–L3, appended with long chain alkyl and/or ester groups, is reported. The X-ray crystal structure aspects of one such complex, trans-PdCl2(rac-2-heptadecyl-4,5-dihydro-5-methyl-2-oxazole)2 (i.e. PdCl2(L1)2: 3), is described. This latter material contains one of the longest alkyl chains to be crystallographically characterised appended to an oxazoline ligand. The complexes reported herein represent the first transition metal derivatives of these high molecular weight, long chain and presumably low polarity monodentate oxazoline ligands. A combination of spectral and theoretical calculations (semi-empirical PM6(tm) level of theory) are used to support the proposed structure in the case of the hydrates of NiCl2 and CoBr2 complexes derived from L1. A trio of PdCl2 complexes of the ligand set are likewise detailed. Complex 3 is shown to be a useful pre-catalyst for the promotion of a Heck coupling reaction between bromobenzene and styrene under typical conditions.

The Transition Metal Chemistry of PGeP and PSnP Pincer Heavier Tetrylenes

This review article collects and discusses the syntheses of the currently known metal‐free heavier tetrylenes having a PEP pincer topology (E = tetrel atom) as well as their transition metal derivative chemistry. To date, only five PGeP germylenes and two PSnP stannylenes have been isolated. These compounds have been successfully synthesized by treating GeCl2(diox) (diox = 1,4‐dioxane), GeCl2(NHC) (NHC = N‐heterocyclic carbene) or SnCl2 with two equivalents of an appropriate lithiated phosphine. Their transition metal chemistry is dominated by processes in which, in addition to the coordination of one or both phosphane groups, the E atom ends inserted into M–M or M–X (X = anionic group) bonds. Only in a few occasions a simple coordination of the tetrylene fragment (as a neutral two‐electron‐donor ligand) has been observed. The structural and bonding characteristics of the metal‐free PEP tetrylenes and of relevant examples of their transition metal derivatives are also surveyed.

Spherical Sacrificial ZnO Template–Derived Hybrid Ni/Co3O4 Cubes as Efficient Bifunctional Electrocatalyst for Overall Water Splitting

Heterostructure transition metal derivatives have been extensively studied in electrocatalysis, but most of the hybrid samples are on nanoscale with low stability and tap density. ZnO microspheres are applied as a sacrificial template, followed by alkaline etching and aluminum reduction to construct Ni/Co3O4 microcubes. The porous hybrid microcubes show stirring performance in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For HER, it exhibits comparable overpotential of 145 mV at 10 mA cm−2 as Pt/C (101 mV) and desirable stability. For OER, it outperforms RuO2 with lower overpotential when the current exceeds 17.8 mA cm−2 and much smaller Tafel slope of 34 mV dec−1 versus RuO2 (72 mV dec−1). The potential activity is assigned to the charge transfer at the heterointerfaces, and the synergic effects of the Ni/Co3O4 phases, which possibly will cast light on the design of microscale bifunctional electrocatalysts.

Синтез и строение арильных соединений фосфора

Based on an analysis of the literature published from the late 20th century to the beginning of the 21st century, methods for the synthesis of some complex tetraorganylphosphonium salts are systematized and described, along with the features of the chemical transformations of pentaphenylphosphorus, which was first obtained in 1953. The tetraorganylphosphonium salts were known much earlier, however, the features of the synthesis of transition metal complexes, which are usually obtained from tetraorganylphosphorus halides and metal halides, have not been sufficiently studied. The present review is devoted to the discussion of these topics, since the famous Wittig Reaction is associated with aryl phosphorus compounds, which allows synthesizing alkenes of a given structure, and derivatives of transition metals rightfully occupy a special place among catalysts of various chemical processes. The continuation of these classical studies in the field of chemistry of organoelemental compounds takes place at one of the leading universities in Russia - South Ural State University in the laboratory of chemistry of organoelemental compounds at the Faculty of Chemistry. This article aims at familiarizing the reader with the achievements of Professor V.V. Sharutin and his students in the field of organophosphorus compounds. The main attention is paid to the reactions of pentaphenylphosphorus and its derivatives, as well as methods for the synthesis of ionic complexes of silver, gold, copper, titanium, zirconium, hafnium, ruthenium, osmium, cobalt, rhodium, iridium, palladium and platinum with tetraorganylphosphonium cations. The structural features of the described compounds and the possibility of using transition metal complexes in some catalytic reactions are described.

Dispersion Effects in Stabilizing Organometallic Compounds: Tetra-1-norbornyl Derivatives of the First-Row Transition Metals as Exceptional Examples.

In 1972 Bower and Tennett first synthesized a series of tetra-1-norbornyl derivatives, (nor)4M, of the first-row transition metals from titanium to cobalt. These were found to be exceptionally stable for homoleptic metal alkyls containing only metal-carbon σ-bonds. The theoretical energies for the dissociation of 1-norbornyl ligands from these unusually high oxidation state organometallics through the reactions (nor)4M → (nor)3M + nor• and (nor)4M → (nor)2M + nor-nor indicate that dispersion effects play an important role in determining their exceptional stability. Thus, all of the (nor)4M (M = Ti to Cu) derivatives are viable with respect to 1-norbornyl radical dissociation when the London dispersion effect is considered. However, (nor)4Cu becomes disfavored if the dispersion correction is ignored. Thus, the stability of the (nor)4M molecules is seen to arise from the favorable combination of steric and dispersion force effects of the four 1-norbornyl groups tetrahedrally disposed around the metal atom and maximizing the dispersion attraction between them in a spherical hydrocarbon structure with a central metal atom. The tri-1-norbornyl derivatives (nor)3M appear be disfavored with respect to disproportionation into (nor)4M + (nor)2M. This is consistent with the experimental syntheses of the (nor)4M (M = Cr to Co) derivatives with the metal in the +4 oxidation by reactions with 1-norbornyllithium with metal halides in the +2 or +3 metal oxidation states. Both the OPBE method and the BPW91 method predict high-spin states for the d2 and d3 complexes (nor)4Cr and (nor)4Mn but low-spin states for (nor)4Fe and (nor)4Co, consistent with experiment.

Continuous Network of Phase-Tuned Nickel Sulfide Nanostructures for Electrocatalytic Water Splitting

To date, nanostructures of 3d-group transition metal (i.e., Fe, Co, Ni, etc.) derivatives show the highest electrocatalytic performance among non-noble-metal electrocatalysts for water splitting in acidic electrolyte. However, the poor electrochemical conductivity (∼10–4 S/cm) of nanostructures restricts practical application for overall electrocatalytic activity. Herein, continuously networked nanostructures of phase-tuned nickel sulfide foams for efficient water splitting electrocatalysts in both acidic and alkaline electrolytes are reported. Because continuously networked nanostructures of nickel sulfide foams possess an integral structure, they exhibit high electrochemical conductivity (∼1 S/cm), which eases adsorption/desorption of H+ and OH– ions for efficient overall water splitting. By tuning the stoichiometry of sulfur, four different phases of continuously networked nanostructures of nickel sulfides (αNiS, βNiS, Ni3S2, and Ni7S6) foams are formed by facile phase transformation of nickel. Among t...

Recent advances in isopolyoxotungstates and their derivatives

During the past decade, isopolyoxotungstates (iso-POTs) and their derivatives have been greatly developed due to their unique structures and potential applications in luminescence, magnetism, catalysis etc. This brief review is principally focused on the main research progress on iso-POTs, iso-POT-based transition-metal derivatives, iso-POT-based rare-earth derivatives, iso-POT-based organometallic derivatives and iso-POT-based heterometallic derivatives, and gives a summary of some representative examples of their syntheses, structures and related properties. In addition, an outlook on the future of this area is presented in the final section. We believe that this systematic commentary on iso-POTs and their derivatives will not only disclose a rich set of iso-POT structures, but also reveal a more promising direction for the further functionalization of iso-POTs.