Metal Acetylacetonates Research Articles

Peroxide-Free and Amine-Free Redox Free Radical Polymerization: Metal Acetylacetonates/Stable Carbonyl Compounds for Highly Efficient Synthesis of Composites

New peroxide-free, amine-free, and phosphine-free redox free radical polymerization (RFRP) initiating systems comprising remarkably stable (i) metal acetylacetonates (Mn(acac)3, Cu(acac)2) and (ii) carbonyl compounds bearing labile hydrogen in the α-position are presented for polymerization initiation under mild conditions (under air, at room temperature, nonpurified monomers). The systems proposed in this work are competitive or even outranked the well-known peroxide-based RFRP reference in several criteria: (i) toxicity, (ii) stability, (iii) surface curing, (iv) overall double-bond conversions, and (v) workability of the RFRP mixture (longer gel times are now possible). Radical initiating reactions are studied using many complementary experimental/theoretical techniques: optical pyrometry, thermal imaging, Raman confocal microscopy, electron spin resonance (ESR), ESR spin trapping (ESR-ST), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), density functional theory (DFT), simulations of bond dissociation energies (BDE), reaction enthalpies, and DFT simulations of seven unknown ESR-ST adducts. A full consistent picture of the chemical mechanisms involved in these new redox systems is provided.

The thermal decomposition and analyses of metal tris-acetylacetonates

In earlier work, we studied the phase transitions of a number of metal(III) acetylacetonates using thermal analysis (DSC) and coupled that with solid-state single crystal X-ray structures. From these studies, we found it necessary to explore the complexes of Al(III), Cr(III), Mn(III), Fe(III) and Co(III) in more detail. In the process of examining the extant data on the tris-metal acetylacetonates, we discovered that there were a broad range of applications in which those substances seem to have interesting and unusual properties, including thermal and radiation sensitivity, resulting in the formation of radicals which were documented to be useful in the initiation and promotion of polymerization, etc. Thus, we decided to combine our synthetic and crystallization experience with thermal studies (e.g., DSC, MS and TG) in an attempt to document the nature of metal tris-acetylacetonates and their thermalization products between room temperature and their decomposition temperatures.

Bifunctional Solid Catalyst for Organic Reactions in Water: Simultaneous Anchoring of Acetylacetone Ligands and Amphiphilic Ionic Liquid "Tags" by Using a Dihydropyran Linker.

The use of solid catalysts to promote organic reactions in water faces the inherent difficulty of the poor mass-transfer efficiency of organic substances in water, which is often responsible for insufficient reaction and low yields. To solve this problem, the solid surface can be manipulated to become amphiphilic. However, the introduction of surfactant-like moieties onto the surface of silica-based materials is not easy. By using an accessible dihydropyran derivative as a grafting linker, a surfactant-combined bifunctional silica-based solid catalyst that possessed an ionic liquid tail and a metal acetylacetonate moiety was prepared through a mild Lewis-acid-catalyzed ring-opening reaction with a thiol-functionalized silica. The surfactant-combined silica-supported metal acetylacetone catalysts displayed excellent catalytic activity in water for a range of reactions. The solid catalyst was also shown to be recyclable, and was reused several times without significant loss in activity.

Chiral, Heterometallic Lanthanide–Transition Metal Complexes by Design

Achieving control over coordination geometries in lanthanide complexes remains a challenge to the coordination chemist. This is particularly the case in the field of molecule-based magnetism, where barriers for magnetic relaxation processes as well as tunneling pathways are strongly influenced by the lanthanide coordination geometry. Addressing the challenge of design of 4f-element coordination environments, the ubiquitous Ln(hfac)3 moieties have been shown to be applicable as Lewis acids coordinating transition metal acetylacetonates facially leading to simple, chiral lanthanide–transition metal heterodinuclear complexes. The broad scope of this approach is illustrated by the synthesis of a range of such complexes LnM: LnM(hfac)3(μ2-acac-O,O,O′)3 (Ln = La, Pr, Gd; M = Cr, Fe, Ga), with approximate three-fold symmetry. The complexes have been crystallographically characterized and exhibit polymorphism for some combinations of 4f and 3d metal centers. However, an isostructural set of systems spanning several lanthanides which exhibit spontaneous resolution in the orthorhombic Sohncke space group P212121 is presented here. The electronic structure and ensuing magnetic properties have been studied by EPR spectroscopy and magnetometry. The GdFe, PrFe, and PrCr complexes exhibit ferromagnetic coupling, while GdCr exhibits antiferromagnetic coupling. GdGa exhibits slow relaxation of the magnetization in applied static fields.

Reverse Offset Printing of Semidried Metal Acetylacetonate Layers and Its Application to a Solution-Processed IGZO TFT Fabrication.

The submicrometer resolution printing of various metal acetylacetonate complex inks including Fe, V, Mn, Co, Ni, Zn, Zr, Mo, and In was enabled by a robust ink formulation scheme which adopted a ternary solvent system where solubility, surface wettability, and drying as well as absorption behavior on a polydimethylsiloxane sheet were optimized. Hydrogen plasma in heated conditions resulted in bombarded, resistive, or conductive state depending on the temperature and the metal species. With a conductivity-bestowed layer of MoO x and a plasma-protecting layer of ZrO x situated on the top of an IGZO layer, a solution-processed TFT exhibiting an average mobility of 0.17 cm2/(V s) is demonstrated.

Modulation of the Coordination Environment around the Magnetic Easy Axis Leads to Significant Magnetic Relaxations in a Series of 3d-4f Schiff Complexes.

A series of Salen-type Zn(II)-Dy(III) complexes [L1Zn(II)ClDy(III)(acac)2]·H2O (1), [L1Zn(II)BrDy(III)(acac)2]·H2O (2), [L1Zn(II)(H2O)Dy(III)(acac)2]·CH2Cl2·PF6 (3), [L2Zn(II)(H2O)Dy(III)(acac)2]·PF6 (4), and Co(III)-Dy(III) complexes [L1Co(III)Br2Dy(III)(acac)2]·CH2Cl2 (5), [L2Co(III)Cl2Dy(III)(acac)Cl(MeO)] (6), [L2Co(III)Cl2Dy(III)(acac)Cl(H2O)] (7), and [L2Co(III)Cl2Dy(III)(NO3)2(MeO)] (8) heterobinuclear single-molecule magnets (SMMs) were synthesized and magnetically characterized. These complexes were constructed by incorporating diamagnetic Zn(II) and Co(III) ions with acetylacetone (acac) and compartmental Schiff-base ligands (H2L1 = N, N'-bis(2-oxy-3-methoxybenzylidene)-1,2-phenylenediamine; H2L2 = N, N'-bis(2-oxy-3-methoxybenzylidene)-1,2-diaminocyclohexane). In the Zn(II)-Dy(III) (1-4) system, the coordination environments of the Dy(III) ions are nearly identical, but the apical coordination atom to the Zn(II) ion is different. Complexes 1, 2, and 4 displayed no magnetic relaxation in the absence of external magnetic field, but complex 3 displayed more pronounced SMM behavior with a relaxation energy barrier Ueff/ kB 38 K and magnetic hysteresis at 1.8 K. The SMM performances of 5, 6, and 7 were enhanced significantly by incorporating an octahedral Co(III) instead of square-pyramidal Zn(II) and replacing one of acac- group around Dy(III) ion by a neutral O atom, displaying Ueff of 167, 118, and 75 K as well as magnetic hysteresis up to 3.5 K. These studies indicated that the remote diamagnetic Zn(II) and Co(III) ions played a key role, and the SMM properties were very strongly related to the special coordination atoms configuration around Dy(III) ion. When this coordination configuration around was broken as 8 exhibited, however, it resulted in a dramatically decreased SMM performance. From this work, the key factors that significantly affect the SMM performance of these heteronuclear Zn(II)/Co(III)-Dy(III) SMMs are unambiguously presented.

Decoration of Carbon Nanomaterial Powders with Dispersed Platinum Metal Particles

Carbon nanomaterials (fullerite, detonation nanodiamonds, Taunit, fullerenol, fullerene-containing black) were decorated with platinum group metal nanoparticles in situ in one step by low-temperature combustion (~250–270°С) of a powdered mixture of platinum metal acetylacetonate [Pt-M(асас)n, Pt-М = Pt(II), Pd(II), Rh(III), Ir(III), acac = CH3COCHCOCH3, n is the oxidation state of Pt-М] with carbon nanomaterials in air. As shown by thermal analysis, the process is based on thermal oxidative degradation of the organometallic complex, catalyzed by carbon nanomaterials, with oxidation (combustion) of the organic moiety and release of the metal into the condensed phase. The thermal process in an open system occurs in the glowing mode (210–250°С); the size of the nanoparticles formed is 7–30 nm. Under the conditions restricting the air access to the reaction mixture and free outflow of gaseous products formed by oxidation of acac ligands, the nanoparticle size decreases to 3–10 nm. The particle size depends on the metal amount in the initial powder mixture and on the support morphology.

Diffusivities of metal acetylacetonates in liquid ethanol and comparison with the transport behavior in supercritical systems

Diffusion coefficients of chromium(III) acetylacetonate, palladium(II) acetylacetonate, nickel(II) acetylacetonate, vanadyl(II) acetylacetonate, and titanium(IV) oxyacetylacetonate in liquid ethanol were measured by chromatographic peak broadening method (CPB) over the range of temperature 303.15–333.15 K at atmospheric pressure. The dependencies of D12 upon temperature and Stokes–Einstein coordinates were examined in detail. Moreover, the experimental data were modeled using nine equations from the literature to test their accuracy and prediction ability. The lower deviations were achieved by the 2-parameter correlation of Dymond-Hildebrand-Batschinski (0.32–2.17 %), the 1-parameter correlation of Tracer Liu-Silva-Macedo (1.58–3.88 %), and the 2-parameter correlations of Magalhães et al. (0.55–2.32 %). Finally, the proposed correlation based on hydrodynamic approach was found to well represent palladium(II) acetylacetonate and chromium(III) acetylacetonate systems in supercritical carbon dioxide and liquid ethanol, with the average absolute relative deviation of 3.15 and 5.02 %, respectively.

A study of the structural and morphological properties of Ni–ferrite, Zn–ferrite and Ni–Zn–ferrites functionalized with starch

Zinc–ferrite, nickel–ferrite and mixed nickel–zinc ferrites were successfully synthesized via the thermal decomposition method from acetylacetonate complexes. To control the particle size and enhance dispersibility in an aqueous medium, starch, a natural and biocompatible compound, was used for the first time for coating such magnetic powders. X-ray powder diffraction (XRPD) was performed to study the structural properties of all samples. The presence of a single-phase spinel structure as well as the cation distribution in both sites of all investigated magnetic powders was confirmed. The values of unit cell parameters obtained from the results of the Rietveld analysis decreased, while the average crystallite size increased with increasing Ni2+ content. The average microstrain parameters unambiguously showed a change in the spinel structure with cation distribution. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) analyses were also utilized to characterize the synthesized materials, corroborating the XRPD data. The obtained results indicated that functionalization by starch was successfully achieved.

Morphological and Electrochemical Optimization of Solid Oxide Fuel Cell (SOFC) Diffusion-Blocking Layer and Cathode Layer Fabricated By Reactive Spray Deposition Technology (RSDT)

SOFCs typically operate up to 1000ºC [1]. This temperature is notably higher than the temperatures at which other fuel cells, such as PEM fuel cells, run. This elevated temperature offers distinct advantages, such as greater efficiency due to faster reaction kinetics, flexibility to use fuels other than hydrogen, and relatively high resistance to impurities in the fuel [1]. When running hydrogen, the faster reaction kinetics also eliminate the need for noble metal catalysts, which are an inherent component of PEM fuel cells; instead the anode and cathode in SOFCs can be made of relatively inexpensive ceramics. The cost of SOFCs can be further reduced by decreasing the operating temperature to 500-650ºC [2]. In this temperature range LSCF (La0.6Sr0.4Co0.2Fe0.8O3-δ) is a commonly used cathode materials because of its good ionic and electronic conductivity [2]. A common electrolyte used in SOFCs is YSZ (Zr0.92Y0.08O2- δ), which reacts with LSCF to form SrZrO3 [2]. The presence of SrZrO3 leads to resistive losses in the cell. To mitigate this, a diffusion-blocking layer of GDC (Ce0.9Gd0.1O1.95) can be applied between the YSZ and LSCF. Previous work suggests that GDC blocking layers applied by RSDT lead to better cell performance than GDC applied using traditional screen-printing techniques [2,3]. This work focuses on optimizing the coating of a GDC blocking layer and LSCF cathode layer on SOFC half cells with NiO,YSZ anode support, NiO,YSZ anode functional layer, and YSZ electrolyte using RSDT. RSDT is an open-atmosphere, flame-based deposition process that uses inexpensive solvents and precursors (i.e. toluene and metal acetylacetonates) and performs a direct deposition of GDC and LSCF layers onto the cell [4]. By using RSDT, a dense GDC layer with good adhesion can be achieved at ~1000°C, which is a relatively low temperature compared to the ~1400°C at which GDC is traditionally processed. This lower temperature allows for reduced production costs and limits the inter-diffusion of the YSZ and GDC. Image (a) of the attached figure shows plan-view SEM of the RSDT-fabricated GDC layer on a half cell. This thin, dense GDC layer is expected to be transparent in SEM [2]; the large grains are the underlying YSZ. Energy Dispersive X-Ray Spectroscopy indicates the presence of cerium. Gadolinium is not detected, which is likely the result of its intended low mole ratio. The cathode is fabricated by simultaneously spraying a slurry of pre-synthesized LSCF nanoparticles and spraying LSCF nanoparticles synthesized directly in the flame. Preliminary testing shows that cells with the RSDT-fabricated cathode have less mass-transfer resistance at high current densities than cells with traditional LSCF cathodes (plot (b) of attached figure). These performance tests were conducted by FuelCell Energy at 750°C with humidified hydrogen on the anode and air on the cathode. To improve the performance of a cell with RSDT-fabricated GDC blocking layer and LSCF cathode, it is important to decrease the ohmic resistance of the cell. This can be achieved by increasing the ionic and electronic conductivity of the LSCF cathode and by increasing the area of the triple phase boundary (TPB). In this work, the LSCF cathode morphology is tailored to optimize its ionic and electronic conductivity, TPB, and mass transfer resistance. The surface morphology of the dense GDC is also adjusted to optimize TPB. As part of the optimization, the morphology of the deposited layers is analyzed by X-Ray Diffraction and Scanning Electron Microscopy. Additionally, performance testing and electrochemical testing is carried out on the cells. This establishes a correlation among RSDT processing parameters, cell morphology, and cell performance.

Адсорбционные свойства поверхностных слоев силикагеля, модифицированных ацетилацетонатами переходных металлов

Адсорбционные свойства поверхностных слоев силикагеля, модифицированных ацетилацетонатами переходных металлов

Metal Acetylacetonate–Bidentate Ligand Interaction (MABLI) (Photo)activated Polymerization: Toward High Performance Amine-Free, Peroxide-Free Redox Radical (Photo)initiating Systems

Free radical polymerization (FRP) initiation from metal acetylacetonate–bidentate ligand interaction (MABLI) under mild conditions (room temperature, under air) is discussed here for different metal centers (Mn, V, and Cu). First, without light, in MABLI systems such as V(acac)3/2-diphenylphosphinobenzoic acid (2dppba), Mn(acac)3/2dppba, or Cu(acac)2/2dppba, electron-rich aryl (Ar•) radicals were conveniently and efficiently produced by the reaction of electron-poor acac• radicals with the iodonium salt (Iod), leading to an enhancement of pure redox (no light) polymerizations. Second, it was found that V(III)*/Iod reaction is generating aryl (Ar•) radicals at a high enough rate to initiate a photopolymerization process upon mild irradiation (LED@405 nm). This reaction can be implemented in redox photoactivated systems (e.g., using three-component V(acac)3/2dppba/Iod systems) in order to spectacularly enhance a slow redox process from 40 °C exothermicity in 800 s to 93 °C in less than 200 s. Third, an impr...

Nanohybrid Complexes with Molybdenyl Acetylacetonate, Schiff Base and Lacunary Keggin-Type Polyoxometalates: Synthesis and Catalytic Epoxidation of Olefins in the Presence of tert-Butyl Hydroperoxide

Two new nanohybrid compounds as heterogenous catalyst were prepared by reaction of Lacunary Keggin-type polyoxometalate compounds ([SiW11O39]8− and [PW11O39]7−), molybdenyl acetylacetonate [MoO2(acac)2] and ethylenediamine (en), (1 and 2 respectively) species and characterized by elemental analysis and various routine techniques. The catalytic activities of these nanocatalysts examined for the epoxidation of linear, cyclic and phenyl-substituted olefins using tert-Butyl hydroperoxide (tert-BuOOH) as oxidants. The synergistic effect between molybdenyl acetylacetonate complex and lacunary Keggin-type polyoxometalate plays an important role in the promotion of catalytic activity. The catalysts were recovered and reused at least six times without obvious losing of activity and the yields for catalyst recovery are all above 91%.

Electronic structure of binuclear acetylacetonates of boron difluoride

The electronic structure of boron difluoride acetylacetonate and its three derivatives was studied using photoelectron and absorption spectroscopy, as well as the density functional theory. In a series of binuclear acetylacetonate complexes containing bridge-moieties of sulfur and selenium atoms, it was found an appreciable mixing of the π3-orbital of the chelate cycle with atomic orbitals S 3p and Se 4p resulting in destabilization of the HOMO levels by 0.4–0.6 eV, in comparison with the monomer. The positively charged fragment C(CH3)-CX-C(CH3) causes the field effect, which leads to stabilization of the LUMO levels by 0.3–0.4 eV and C 1s-levels by 0.5–1.2 eV. An analysis of the research results on the electronic structure made it possible to determine the effect of substituents in the γ position on the absorption spectra, which is mainly determined by the electron density transfer from the chalcogen atoms to the chelate cycles. It is shown that the calculated energy intervals between electron levels correlate well with the structure of the photoelectron spectra of valence and core electrons.

Adsorption Properties of a Silicagel Surface with Grafted Transition Metal Acetylacetonate Complexes

The adsorption properties of a Silipore 200 surface and chemically modified sorption materials containing nickel, cobalt, and copper acetylacetonates are studied via gas chromatography. n-Alkanes (C6–C9) and adsorbates, the molecules of which have different electron-donating and electron-acceptor properties, are used as test compounds. From experimental data on the retention of adsorbates; their differential molar adsorption heats \(\bar q_{dif,1}\); changes in standard differential molar entropy \(\Delta \bar S_{1,C}^S\); and, for polar adsorbates, contributions \(\Delta \bar q_{dif,1(specific)}\) to the energy of dispersive and specific interactions, are calculated. The effect the metal ion in the structure of acetylacetonate has on the characteristics of thermodynamic retention is shown.

Temperature dependence on the mass susceptibility and mass magnetization of superparamagnetic Mn–Zn–ferrite nanoparticles as contrast agents for magnetic imaging of oil and gas reservoirs

ABSTRACTThe mass susceptibility (χmass) and mass magnetization (Mmass) were determined for a series of ternary manganese and zinc ferrite nanoparticles (Mn–Zn ferrite NPs, MnxZn1−xFe2O4) with different Mn:Zn ratios (0.08 ≤ x ≤ 4.67), prepared by the thermal decomposition reaction of the appropriate metal acetylacetonate complexes, and for the binary homologs (MxFe3−xO4, where M = Mn or Zn). Alteration of the Mn:Zn ratio in Mn–Zn ferrite NPs does not significantly affect the particle size. At room temperature and low applied field strength the mass susceptibility increases sharply as the Mn:Zn ratio increases, but above a ratio of 0.4 further increase in the amount of manganese results in the mass susceptibility decreasing slightly, reaching a plateau above Mn:Zn ≈ 2. The compositional dependence of the mass magnetization shows less of a variation at room temperature and high applied fields. The temperature dependence of the mass magnetization of Mn–Zn ferrite NPs is significantly less for Mn-rich compositions making them more suitable for downhole imaging at higher temperatures (>100 °C). For non-shale reservoirs, replacement of nMag by Mn-rich Mn–Zn ferrites will allow for significant signal-to-noise enhancement of 6.5× over NP magnetite.

Metal Acetylacetonate–Bidentate Ligand Interaction (MABLI) as highly efficient free radical generating systems for polymer synthesis

Metal Acetylacetonate–Bidentate Ligand Interaction (MABLI) is presented here as a new chemical mechanism for the highly efficient generation of free radicals for polymer synthesis.

Efficient solution-processed yellow/orange phosphorescent OLEDs based on heteroleptic Ir(Ⅲ) complexes with 2-(9,9-diethylfluorene-2-yl)pyridine main ligand and various ancillary ligands

Abstract Efficient solution-processible yellow/orange emissive phosphors are highly required in solution-processed phosphorescent organic light-emitting diodes (s-PhOLEDs). With respect to phenyl pyridine (ppy)-type Ir(III) complexes, 2-(9,9-diethylfluoren-2-yl)pyridine (Flpy)-type Ir(III) complexes have huge potential in yellow/orange s-PhOLEDs due to their extended conjugation and excellent solubility in common organic solvents. Herein, a new series of phosphorescent Ir(III) complexes, i.e. Ir(Flpy)2pic-N O, Ir(Flpy-CF3)2pic-N O, Ir(Flpy-CF3)2dbm and Ir(Flpy-CF3)2acac, based on Flpy main ligand and picolinic N-oxide (pic-N O), acetylacetone (acac), and dibenzoyl methane (dbm) ancillary ligands are synthesized. The photophysical, electrochemical, and electroluminescent (EL) properties of these phosphorescent Ir(III) complexes are investigated in details. By introducing the CF3 group in Flpy ligand and varying the ancillary ligands, the emission spectra of these phosphorescent complexes are tuned in a large range with EL emission peaks from 544 nm to 588 nm. The s-PhOLEDs employing these phosphors show promising EL performance with maximum external quantum efficiency (EQE) from 15.4% to 23.7% and high power efficiency from 61.9 l m W−1 to 80.4 l m W−1. These highly efficient phosphorescent Ir(III) complexes may serve as ideal chromaticity components in solution-processed full-color displays and lighting devices.

An Overview of Metal Acetylacetonates: Developing Areas/Routes to New Materials and Applications in Organic Syntheses

In this review, we discuss the nature and bonding, role of metal acetylacetonates as precursors for nanoparticle research, polymer science, catalysis and their mechanistic aspects, which we believe to provide an illustrative overview of current research directions in this rapidly developing field. The chosen examples within this review reflect the remarkable broadness of nanoparticle research, polymer and applications of metal acetylacetonates as catalysts in organic syntheses. The purpose of this review is to provide recent advancements of several catalytic reactions employing well defined metal enolate complexes. Metal enolates are used in a plethora of catalysed reactions. Several catalytic reactions have been highlighted in this review to show where metal enolate complexes have played a significant role in recent years. The ultimate goal of this effort is towards the development of catalysts that impart the selectivities, reactivity, and atom economy needed for cost-effective approaches to a variety of critical chemical transformations.

Evaluating the solvation properties of metal-containing ionic liquids using the solvation parameter model.

Ionic liquids (IL) have been utilized as gas chromatography stationary phases due to their high thermal stability, negligible vapor pressure, wide liquid range, and the ability to solvate a range of analytes. In this study, the solvation properties of eight room temperature ILs containing various transition and rare earth metal centers [e.g., Mn(II), Co(II), Ni(II), Nd(III), Gd(III), and Dy(III)] are characterized using the Abraham solvation parameter model. These metal-containing ILs (MCILs) consist of the trihexyl(tetradecyl)phosphonium cation and functionalized acetylacetonate ligands chelated to various metals. They are used in this study as gas chromatographic stationary phases to investigate the effect of the metal centers on the separation selectivities for various analytes. In addition, two MCILs comprised of tetrachloromanganate and tris(trifluoromethylphenylacetylaceto)manganate anions were used to study the effect of chelating ligands on the selectivity of the stationary phases. Depending on the metal center and chelating ligand, significant differences in solvation properties were observed. MCILs containing Ni(II) and Mn(II) metal centers exhibited higher retention factors and higher peak asymmetry factors for amines (e.g., aniline and pyridine). Alcohols (e.g., phenol, p-cresol, 1-octanol, and 1-decanol) were strongly retained on the MCIL stationary phase containing Mn(II) and Dy(III) metal centers. This study presents a comprehensive evaluation into how the solvation properties of ILs can be varied by incorporating transition and rare earth metal centers into their structural make-up. In addition, it provides insight into how these new classes of ILs can be used for solute-specific gas chromatographic separations. Graphical abstract The solvation properties of eight metal-containing ionic liquids (MCILs) comprised of transition and rare-earth metal centers are evaluated for the first time using gas chromatography. The results reveal that metals comprising the MCILs provide unique separation selectivities for various analytes and that these materials can be exploited as stationary phases in solute-specific gas chromatographic separations.