Alkylamine Complexes Research Articles

Exploring preliminary structural relationships and mitochondrial targeting of fac-[MI(CO)3]-bis(diarylphosphino)alkylamine complexes (M = 99Tc, Re)

Preliminary structural relationships in fac-[MI(CO)3]-bis(diarylphosphino)alkylamine complexes (M = 99Tc, Re), antimicrobial and mitochondrial targeting are reported.

New approach for the synthesis of water soluble fac-[MI(CO)3]+ bis(diarylphosphino)alkylamine complexes (M = 99Tc, Re).

A novel proof-of-concept is reported to modify the water solubility and potential biological effects of a bis(diphenylphosphino)alkylamine (PNP) ligand and the corresponding metal complex, by introducing an amine group on the outer periphery of the pendant ligand arm. Thus, a tertiary butoxycarbonyl protected N'-Boc-ethylenediamine-N,N-bis(diphenylphosphino) (N'-Boc-PNP) ligand (1) was synthesized by reacting the protected ethylenediamine and chlorodiphenylphosphine in a 1 : 2 molar ratio. The corresponding fac-[Re(CO)3(N'-Boc-PNP)Br] (1A) complex was then obtained by reacting N'-Boc-PNP (1) with (Et4N)2fac-[Re(CO)3Br3] in equimolar amounts in DCM at 50 °C. De-protection of the N'-Boc pendant amine group in 1A with TFA leads to fac-[Re(NH3+-PNP)(CO)3Br]·CF3COO- (1B) which is soluble in D2O (>0.05 M). Treating 1B with saturated aqueous NaHCO3 yields fac-[Re(NH2-PNP)(CO)3Br]·MeOH (1C) in near quantitative yield. Although both 1A and 1C are not soluble in D2O, addition of TFA easily generates 1B (31P NMR), confirming the formation of the protonated amine. Isolation of fac-[99Tc(CO)3(N-Boc-PNP)(Cl)] (1D) confirmed that the rhenium and technetium (99Tc) can be easily interchanged in this process. Reported are hence the unique rhenium series of compounds 1A, 1B and 1C and the corresponding technetium complex 1D, unequivocally characterized by single crystal XRD, as well as IR and 1H NMR spectroscopy. Preliminary antimicrobial evaluation indicates that ligand 1 and its respective rhenium complexes (1A-1C) were not active against selected fungi (Candida albicans and Cryptococcus neoformans) and bacteria (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus). These types of ligands and complexes therefore present themselves as excellent radio models for further evaluation using 186Re, 188Re and 99mTc to potentially study the radiotoxicity of appropriately designed complexes.

Interaction of bis(alkylamine)dichloropalladium(II) complexes with CT-DNA and BSA; their synthesis, characterization, antitumor, and antibacterial evaluations

A series of five new and analogous palladium(II) alkylamine complexes of cisplatin derivatives such as cis-[Pd(alkyl-am)2Cl2], where alkyl-am is Ethyl-, Propyl-, Butyl-, Hexyl-, and Octyl-amine, have been prepared. They have been characterized by physicochemical methods such as FT-IR, 1H-NMR, UV-Vis, conductivity measurements and elemental analysis. These synthesized metal complexes were screened for their in-vitro antitumor activity against human MOLT-4 cells. Only [Pd(Octyl-am)2Cl2] showed moderate activity. They were also tested against some gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria by measuring the values of IZ, MIC and MBC. All Pd(II) complexes displayed comparable activity with that of cefazoline as standard antibiotics. To clarify the mode of interaction between these compounds and CT-DNA and (BSA), their interaction behavior was checked using electronic absorption spectroscopy. Results indicated that all of the above mentioned Pd(II) complexes effectively interacted with CT-DNA and BSA at low concentration and the distance between the interacted Pd(II) complexes and BSA were in the range of 3.00–3.30 nm. Fluorescence emission studies revealed that the complexes quenched CT-DNA pretreated with methylene blue (MB) and the intrinsic fluorescence of BSA through static quenching procedure. Using the binding constant (K b) obtained from fluorescence studies, thermodynamic parameters (ΔG°, ΔH° and ΔS°) suggested that hydrogen bonding and van der Waals forces, as well as hydrophobic interaction, play the major role between metal complexes with CT-DNA and BSA. In all cases the binding forces were spontaneous owing to –ΔG°. Communicated by Ramaswamy H. Sarma

Copper(I)-alkylamine mediated synthesis of copper nanowires.

Formation of a Cu(i)-alkylamine complex is found to be the key step for Cu(ii) ions to reduce to Cu(0) in the presence of glucose. Also, alkylamines in Cu nanowire synthesis serve triple roles as a reducing, complexation and capping agent. Alkylamines reduce Cu(ii) to Cu(i) at above 100 °C and protect the Cu(i) by forming a Cu ion-alkylamine coordination complex with a 1 : 2 ratio in an aqueous solution. With respect to the 1 : 2 complex ratio, the additional free alkylamines ensure a stable Cu(i)-alkylamine complex. After completion of Cu(i)-Cu(0) reduction by glucose, alkylamines remain on Cu(0) seeds to regulate the anisotropic growth of Cu nanocrystals. Long-chain (≥C16) alkylamines are found to help produce high-quality Cu nanowires, while short-chain (≤C12) alkylamines only produce CuO products. Furthermore, Cu nanowire synthesis is found to be sensitive to additional chemicals as they may destabilize Cu ion-alkylamine complexes. By comparing the Cu(i)-alkylamine and Maillard reaction mediated mechanism, the complete Cu nanowire synthesis process using glucose is revealed.

Modulating the Growth Rate, Aspect Ratio, and Yield of Copper Nanowires with Alkylamines

This article shows how the chain length of alkylamine capping agents and the corresponding stability of their self-assembled monolayers on a Cu surface determines the growth rate, yield, and dimensions of Cu nanowires produced in a solution-phase synthesis. Of the 10 linear alkylamines that were tested, only those with 12 or more carbon atoms induced growth of nanowires. The length, yield, and growth rate of nanowires were larger for shorter alkylamines. As the Cu nanowire growth rates were up to 1050 times smaller than the calculated diffusion-limited growth rates—and the alkylamine chain length had no significant effect on the in situ generation of the reducing agent—we conclude the rate of alkylamine-mediated Cu nanowire growth is limited by charge transfer. Electrochemical measurements indicate longer alkylamines form more effective passivation layers that greatly decrease the rate at which Cu–alkylamine complexes are reduced onto a Cu surface. Molecular dynamics simulations show that the energy requi...

Oil-in-Water Emulsions Stabilized by Acylglutamic Acid-Alkylamine Complexes as Noncovalent-Type Double-Chain Amphiphiles.

We have studied the preparation and stabilization mechanism of oil-in-water-type emulsions in the presence of amphiphilic 1:1 stoichiometric complexes of acylglutamic acids (CnGlu) with tertiary alkylamines (CnDMA). Relatively stable emulsions were obtained when C16Glu-C16DMA (or C18Glu-C18DMA), hexadecane, and water were homogenized at 80 °C and then stored at room temperature. The gel-liquid crystal phase transition temperatures (Tc) of C16Glu-C16DMA and C18Glu-C18DMA dispersed in water were determined to be ca. 39 and 53 °C, respectively. This indicates that the complexes form an adsorbed layer at the oil/water interface during the homogenization process above the Tc and then change into a gel during storage at room temperature. The gel phase formed at the oil/water interface prevents the oil droplets from coalescing. In contrast, shorter chain analogues (C10Glu-C10DMA and C12Glu-C12DMA) did not yield stable emulsions because their adsorption layers were not able to prevent coalescence of the oil droplets (i.e., the Tc of these analogues was below the room temperature). We have also demonstrated that the dispersion stability of these emulsion systems can be controlled by changing the aqueous pH.

PH-sensitive Wormlike Micelle and Hydrogel Formation by Acylglutamic Acid–Alkylamine Complex

pH-sensitive viscoelastic fluids were obtained through the formation of wormlike micelles and hydrogels. These assemblies result from the 1:1 stoichiometric complex formation of acylglutamic acid (...

Cu(II)-alkyl amine complex mediated hydrothermal synthesis of Cu nanowires: exploring the dual role of alkyl amines.

Ligands/surfactants play an important role in the synthesis of anisotropic nanomaterials. Other than site specific binding to the crystal plane, they can also undergo complexation with metal ions, altering the nature of the metal complex. The ligand-metal complex formation could be sufficient to modify the reaction kinetics and could affect the size and morphology of the nanostructures. In this article, we investigated such a change in the metal precursor caused by ligands (i.e., alkyl amines) in the hydrothermal synthesis of Cu nanowires in the presence of glucose as a reducing agent. Comparative studies were carried out with other nitrogen-based surfactants such as cetyl trimethyl ammonium bromide and polyvinyl pyrrolodine. Our experimental results confirmed the complex formation of Cu(2+) ions with alkyl amines and its application for nanowire synthesis. Slow reduction of this complex allows for the generation of twinned seeds, which are later grown into nanowires by consuming newly generated seeds in the presence of excess alkyl amine.

Electron-rich ligand modified, ferromagnetic luminescent cis-[CoIII(en)2(RNH2)Cl]Cl2 complexes and their electrochemical reduction behavior

Abstract Luminescent cis -[Co III (en) 2 ( R NH 2 )Cl]Cl 2 (where R NH 2 = Hex n NH 2 , Pen n NH 2 , Bu i NH 2 , Bu n NH 2 , Pr n NH 2 , EtNH 2 , MeNH 2 , Bz n NH 2 ) complexes exhibiting ferromagnetism with some rationalization of magneto-structural features have been synthesized. Such characteristics were verified using auxiliary R NH 2 ligands. The complexes show emission (λ em ~ 411 nm and τ 1 ~ 3, τ 2 ~ 10, τ 3 ~ 0.7 ns) in fluid solutions upon excitation at λ ex = 360 nm. The manifestation of luminescence is attributed due to ligand-to-metal charge transfer emissive state. Electron rich ligand permits a significant reduction in the lifetime of the prominent emitting state Co(III)–Hex n NH 2 ( τ 2 = ~ 9.5 ns) 2 ( τ 2 = ~ 12.3 ns) due to (i) destabilization of d–d mixed LMCT emitting state, and (ii) smaller HOMO–LUMO gap. The E pc = 357–396 mV values observed for Co III (en) 2 ( R NH 2 )Cl 2 + in solvents such as DMSO, water and water/Pr i OH shows metal-centered reduction and a simple one electron transfer process because the current function (I pc /ν 1/2 ) is independent of sweep rate (50–350 mV s − 1 ). Importantly, cobalt(III) complex with short chain R NH 2 exhibits higher saturation magnetization; M s = 150.8 × 10 − 4 μ B /Co 3 + than complex with long chain R NH 2 , in which M s = 0.5 × 10 − 4 μ B /Co 3 + at 298 K, this indicates the manifestation of ferromagnetic coupling in Co III (en) 2 ( R NH 2 )Cl 2 + cation. In essence, the effect of R NH 2 on luminescence, electrochemical and magnetic properties of cis -[Co III (en) 2 ( R NH 2 )Cl]Cl 2 has been rationalized. Such correlation provides an outcome on the signature of the substituent, R NH 2 moiety in cobalt(III)–alkyl amine complexes.

Synthesis of nickel metal nanoparticles via a chemical reduction of nickel ammine and alkylamine complexes by hydrazine

Nickel nanoparticles were prepared from their coordination compounds, such as [Ni(NH3)6]Cl2, [Ni(N2H4)2Cl2], [Ni(HNEt2)6]Cl2, and [Ni(H2NBu)6]Cl2 in aqueous solution by chemical reduction. The reaction of nickel ammine and alkylamine complexes with hydrazine monohydrate as a reducing agent was carried out at 90 °C and pH = 10–12. Depending on the influencing parameters such as oxidizing agent, pH, and temperature, the hydrazine reaction can be carried out in different pathways. The chemical reduction method is a simple procedure and also is the best one in the controlling of composition, size, and shape of Ni powder. The reduction of nickel complexes into the metallic Ni powder occurs via the dissociation of complexes and reduction by hydrazine in alkaline solution. Therefore, complexing agents have the most effect on the reduction reaction. The results show that, when the ligands in complexes were changed from ammine to diethylamine and butylamine, respectively, the crystalline size and morphology of nickel metal nanoparticles are changed. The chemical reduction of nickel complexes into metallic nickel can be accompanied with a change in the crystalline system. The pure nickel crystalline has a face-centered cubic structure. The nickel nanoparticles were characterized using IR spectroscopy, X-ray powder diffraction, scanning electron microscopy and vibrating sample magnetometer analyses.

Proton exchange in acid–base complexes induced by reaction coordinates with heavy atom motions

We extend previous work on nitric acid–ammonia and nitric acid–alkylamine complexes to illustrate that proton exchange reaction coordinates involve the rocking motion of the base moiety in many double hydrogen-bonded gas phase strong acid–strong base complexes. The complexes studied involve the biologically and atmospherically relevant glycine, formic, acetic, propionic, and sulfuric acids with ammonia/alkylamine bases. In these complexes, the magnitude of the imaginary frequencies associated with the proton exchange transition states are <400cm−1. This contrasts with widely studied proton exchange reactions between symmetric carboxylic acid dimers or asymmetric DNA base pair and their analogs where the reaction coordinate is localized in proton motions and the magnitude of the imaginary frequencies for the transition states are >1100cm−1. Calculations on complexes of these acids with water are performed for comparison. Variations of normal vibration modes along the reaction coordinate in the complexes are described.

Excited nanoscale-TiO2 induced interfacial electron transfer reaction of redox active cobalt(III)–alkyl amine complex and the solid surface

Interfacial electron transfer reaction mechanism has been probed using λ = 254 nm excited TiO2 nanoparticles and cis-[CoIII(en)2(RNH2)Cl]Cl2 adsorbates (where RNH2 = MeNH2, EtNH2, PrnNH2, BunNH2, BuiNH2, PennNH2, HexnNH2, BznNH2) in aqueous 2-propanol. These tailor made complexes differing in coordination environment due to RNH2 adhere onto TiO2 surface producing compact nano-TiO2//cobalt(III)–(RNH2) surface compound. The surface of the anatase under UV irradiation is uniquely powerful as adsorbent due to inherent hydrophobic/hydrophilic properties. Therefore, the compact structure facilitates an efficient electron transfer to the Co(III) center resulting a high photoefficiency of formation of Co(II). A model for the electron transfer is arrived by considering: (i) the overlap of conduction band of TiO2 with the acceptor level (Co center): (e−, CB)/(e−, tr) + (CoIII, ad) → CoII and (ii) electronic coupling of donor level (localized on Ti center) with acceptor level (Co center): Ti (center) + (CoIII, ad) → CoII. These pathways indicate accumulation of electron and appropriately available for reduction of the adhered complex ion. Significant insights were gained on the role of RNH2 moiety in modifying compact structure of TiO2–cobalt(III)–RNH2 compound, redox power of semiconductor surface, and the proposed mechanism of interfacial electron transfer reactions.

Synthesis and spectroscopic characterization of cobalt(III)-alkyl amine complexes showing surface affinity: Single crystal X-ray structure determinations

Structurally integrated cobalt(III) complexes showing interesting surface affinity in the interfacial electron transfer reactions were synthesized by incorporating alkyl amines into the coordination sphere of cis-[Co III(en) 2(RNH 2)Cl]Cl 2; (where RNH 2 = MeNH 2 ( 1), EtNH 2 ( 2), Pr n NH 2 ( 3), Bu n NH 2 ( 4), Bu i NH 2 ( 5), Pen n NH 2 ( 6), Hex n NH 2 ( 7) and BzNH 2 ( 8)) through a modified synthetic route. Such complexes are playing important role as electron acceptors in the interfacial electron transfer reactions taking place between metal complex and nanosized semiconductor particles in energy conversion schemes. The complexes were characterized by spectral, 1H NMR and 13C NMR techniques, which indicate the 1,2-diamino ethane site angles are closely similar forming five membered gauche configuration. Single crystal X-ray refinements were made to explore the structures of five complexes ( 2)–( 5) and ( 7). The complexes under study crystallize either in monoclinic or orthorhombic structure and the space consists; ( 2) P2 1 / n, ( 3) P2 12 12 1 , ( 4) Pbca, ( 5) P2 1 and (7) P2 1 / n. The Co(III) ion does not have an electronic preference, however, the structures reflect the conformational preference of RNH 2 ligand.

Multiple regression analyses of kinetics of aquation reactions of some chromium (III) - alkyl amine complexes in mixed solvent media - A study of solvation mechanics

Molecular dynamics of the aquation reactions of the complexes [Cr(en)2Cl2]Cl,[Cr(tn)2Cl2]Cl,[Cr(tetren)Cl]Cl2, [Cr(pn)2Cl2]Cl, [Cr(trien)Cl2]Cl and [Cr(dien)Cl3] have been extensively studied in mixed solvent media. Kinetics and thermodynamic parameters have been evaluated and the results are interpreted carefully in the light of statistical and regression models. Key words: Cr (III) complexes, molecular dynamics, aquation reaction, kinetic parameters, thermodynamic parameter, statistical model, regression model.

ChemInform Abstract: Charge-Transfer Spectroscopy and Photochemistry of Alkylamine Cobalt( III) Complexes

Abstract Spectroscopic and photochemical studies are reported for Co(NH2R)63+, Co(NH2R)5OH23+, and Co(NH2R)5X2+ (where R is methyl, ethyl, or n-propyl, and X is Cl− or Br−). These complexes absorb strongly in the ultraviolet region owing to the presence of one or more ligand-to-metal charge transfer (LMCT) band(s). Irradiation into this charge transfer region results in redox decomposition of the complex with the release of Co2+, alkylamine, and a radical. Photoredox quantum yields measured in fluid solution are generally high and dependent upon excitation wavelength, oxygen concentration, temperature, and solution viscosity. In contrast to their well-studied ammine analogues, the alkylamine complexes (1) possess a N → Co charge transfer band at wavelengths well above 200 nm, (2) undergo redox decomposition from the X → Co and N → Co charge transfer excited states, and (3) avoid an intermolecular decomposition pathway involving photooxidation of the solvent. Reasons for these differences between the two families of complexes are discussed.

DFT studies of reductive elimination, C–H activation and β-hydride elimination in alkyl and aryl palladium amine complexes

The factors affecting C–N bond formation via reductive elimination from Pd(I t Bu)(neopentyl)(morpholide) (I t Bu = 1,3-Di-tert-butyl-imidazol-2-ylidene) are studied computationally. DFT calculations indicate that choosing an alkyl group without β hydrides, such as neopentyl, has a detrimental effect on the possibility of C–N reductive elimination. In the absence of β hydride elimination, a pathway of lower energy than reductive elimination is found, namely morpholide-promoted C–H activation of neopentyl t Bu has a significantly lower activation energy than reductive elimination. Changing the ancillary ligand from I t Bu to tricyclopentylphosphine (P(Cyp)3) has little impact. By contrast, replacing neopentyl by phenyl leads to a c. 50% reduction in activation energy. Study of Pd(I t Bu)(2-methylpropyl)(morpholide) permits comparison of the potential energy surfaces for three possible processes; (1) reductive elimination (2) morpholide-promoted C–H activation and (3) β-hydride elimination and reveals that the activation energies for these processes increase in the order of (3) < (2) < (1). Reductive elimination, C–H activation and β-hydride elimination processes in alkyl and aryl palladium amine complexes are studied computationally, in order to establish why reductive elimination in the alkyl complexes is so elusive.

Large‐Scale Soft Colloidal Template Synthesis of 1.4 nm Thick CdSe Nanosheets

Two-dimensional (2D) nanocrystals have attracted tremendous attention from many researchers in various disciplines because of their unique properties. Since ways of making graphene were devised, there have been significant research efforts to synthesize free-standing 2D nanocrystals of various materials, including metals, oxides, and chalcogenides. Many of these 2D nanocrystals have been generated from exfoliation of materials with layered structures, and tiny amounts of products are generally produced. CdSe nanocrystals are among the most intensively studied nanostructured materials, owing to their many size-dependent optical and electrical characteristics and resulting exciting applications. Herein, we report on the large-scale synthesis of single-layered and lamellar-structured 2D CdSe nanocrystals with wurtzite crystal structure as thin as 1.4 nm by a soft colloidal template method. These free-standing 2D nanocrystals with insulating organic layers at the interface could find many interesting electronic and optoelectronic applications, including in quantum cascade lasers and resonant tunneling diodes utilizing their multiple quantum well structures. Compared to materials with layered crystal structures such as graphite, the synthesis of free-standing 2D nanocrystals of nonlayered materials such as CdSe is extremely challenging, because selective growth along one specific facet among several with similar energies is required. For example, in CdSe with a hexagonal wurtzite crystal structure, a (0001) facet has significantly higher surface energy than other facets, which leads to the formation of many one-dimensional nanostructures. Although there is a slight difference in the surface energies of (1120) and (1100) facets, quantum-confined thin CdSe 2D nanocrystals could not be synthesized using a conventional colloidal chemical route that employs thermal decomposition of precursors at high temperature, because the small difference in the surface energies of these two facets is negated by the high reaction temperature. Consequently, there have been only a few reports on the successful chemical synthesis of 2D CdSe nanocrystals. For example, CdSe inorganic–organic hybrid lamellar structures and CdSe nanoplatelets with zinc-blende structure were synthesized using colloidal chemical routes. However, their 2D growth mechanism has not been clearly elucidated. Furthermore, nanostructural control to form single-layered or multiple-layered nanosheets has not been demonstrated. In the current approach to creating 2D CdSe nanocrystals, we employed a soft template method, and we were able to synthesize not only free-standing single-layered CdSe nanosheets but also lamellar-structured nanosheets by controlling the interaction between organic layers in 2D templates of cadmium chloride alkyl amine complexes. It has been reported that the complex of cadmium halide and diamine can form a cadmium halide /diamine alternating layered structure through diamine bridging and hydrogen bonding between hydrogen atoms of the amine and halogen atoms. Likewise, a [CdCl2(RNH2)2] lamellar complex, which is used herein as a soft template, is expected to form lamellar structures composed of 2D arrays of CdCl2 and alkyl amine by van der Waals attraction between hydrocarbon sidechains of the alkyl amine. The small-angle X-ray scattering (SAXS) patterns of [CdCl2(RNH2)2] complexes with butylamine (BA), octylamine (OA), and dodecylamine (DA) show 00l orders of reflection, which confirms that the complexes formed typical lamellar structures (Supporting Information, Figure S1). A [CdCl2(OA)2] lamellar complex was chosen as the soft template for the synthesis of lamellarstructured CdSe nanosheets because of its optimum reactivity. [*] J. S. Son, Dr. J. Joo, K. Park, Dr. J. H. Kim, Dr. K. An, J. H. Yu, S. G. Kwon, Dr. S.-H. Choi, Prof. T. Hyeon National Creative Research Initiative Center for Oxide Nanocrystalline Materials and School of Chemical and Biological Engineering Seoul National University Seoul 151-744 (Korea) Fax: (+82)2-886-8457 E-mail: thyeon@snu.ac.kr

Synthesis and Reactivities of Cp*Ir Amide and Hydride Complexes Bearing C−N Chelate Ligands

A series of 16-electron Cp*Ir amide complexes with C−N chelating ligands, Cp*Ir[κ2(N,C)-(NHCR2-2-C6H4)] (2a: R = C6H5, 2b: R = CH3), and the chiral version, Cp*Ir[κ2(N,C)-(R)-{NHCH(CH3)-2-C10H6}] (2e), were obtained in good to excellent yields from reactions of 18-electron iridium amine complexes, Cp*IrCl[κ2(N,C)-(NH2CR2-2-C6H4)] (1a: R = C6H5, 1b: R = CH3) and Cp*IrCl[κ2(N,C)-(R)-{NH2CH(CH3)-2-C10H6}] (1e), with a base. The amido complexes 2 readily reacted with 2-propanol to convert into hydrido(amine) complexes 3 in almost quantitative yields. The chiral amido complex has proven to serve as an efficient catalyst for asymmetric transfer hydrogenation of acetophenone with 2-propanol, giving 1-phenylethanol with a moderate ee. The Brønsted basicity on the metal−NH moiety in the amido complexes was evaluated by deprotonation of acetic acid, dimethyl malonate, and acetone, leading to the corresponding acetato(amine) complex 4 and alkyl(amine) complexes 5 and 6, respectively, indicating that the amido−Ir complexes bearing the C−N chelate have more basic properties than those with N-sulfonylated diamine ligands.

Low polydispersed copper-sulfide nanocrystals derived from various Cu–alkyl amine complexes

Copper-sulfides, Cu 2− x S nanocrystals (NCs) have been synthesized using the reaction between a Cu–alkyl amine complex and a sulfur/1-dodecanethiol. Here, 1-dodecanthiol plays an important role to reduce the reaction temperature of sulfuration. The Cu/S composition (the Cu-defect density) of Cu 2− x S NCs depends on the stability of Cu–alkyl amine complex. XPS analyses reveal that the substance of Cu-defect is attributed to an introducing of Cu + 2S 2− 2 species. There is a good correlation between an intensity of a near IR absorption peak and a Cu-defect density estimated by XPS analyses. These results demonstrate that optical properties of Cu 2− x S NCs in a near IR region are tunable.

Highly efficient alcohol oxidation catalyzed by palladium(II)–alkylamine complexes using atmospheric molecular oxygen

Two series of palladium(II)–alkylamine (Pd(Me 2N Cn) 2(OAc) 2, Me 2N Cn: N, N′-dimethylalkylamine, n = 4, 8, 12, and 16) and palladium(II)- N, N′-dialkylamine (Pd( Cn 2NH) 2(OAc) 2, Cn 2NH: N, N′-dialkylamine, n = 4, 8, and 12) were prepared. These homogeneous Pd complexes catalyzed the aerobic oxidation of wide range of alcohols into the corresponding aldehydes and ketones efficiently. For example, a benzylalcohol oxidation proceeded rapidly by means of Pd(Me 2N C12) 2(OAc) 2 with an excellent turnover frequency of up to 96 h −1.