Homologous Series Of Compounds Research Articles

General Synthesis Principles for Ruddlesden–Popper Hybrid Perovskite Halides from a Dynamic Equilibrium

Two-dimensional (2D) Ruddlesden–Popper hybrid perovskites are a homologous series of compounds with the formula A′2An–1BnX3n+1 (A′ = bulky organic cation; A = small organic cation; B = Pb2+ or Sn2+, X = Cl–, Br–, I–; n is an integer) composed of inorganic octahedral layers separated by organic spacer cations. The octahedral layer thickness is modified by the stoichiometry of the A-site cation, but limited methods exist for controlled and discriminating synthesis for all compositions. We report a general synthesis method and its principles that yield phase-pure 2D hybrid perovskites; the chemistry operates within a dynamic equilibrium established by the molar solubility of the compounds within the homologous series. A solvent–antisolvent (HI–acetic acid) pair and the common-ion effect provide selective control over the molar solubility to precipitate phase-pure compounds, as is supported by simple and predictive calculations. Here, this approach is demonstrated in detail with A′ = n-butylammonium, A = meth...

Kinetically Controlled Formation and Decomposition of Metastable [(BiSe)1+δ] m[TiSe2] m Compounds.

Preparing homologous series of compounds allows chemists to rapidly discover new compounds with predictable structure and properties. Synthesizing compounds within such a series involves navigating a free energy landscape defined by the interactions within and between constituent atoms. Historically, synthesis approaches are typically limited to forming only the most thermodynamically stable compound under the reaction conditions. Presented here is the synthesis, via self-assembly of designed precursors, of isocompositional incommensurate layered compounds [(BiSe)1+δ] m[TiSe2] m with m = 1, 2, and 3. The structure of the BiSe bilayer in the m = 1 compound is not that of the binary compound, and this is the first example of compounds where a BiSe layer thicker than a bilayer in heterostructures has been prepared. Specular and in-plane X-ray diffraction combined with high-resolution electron microscopy data was used to follow the formation of the compounds during low-temperature annealing and the subsequent decomposition of the m = 2 and 3 compounds into [(BiSe)1+δ]1[TiSe2]1 at elevated temperatures. These results show that the structure of the precursor can be used to control reaction kinetics, enabling the synthesis of kinetically stable compounds that are not accessible via traditional techniques. The data collected as a function of temperature and time enabled us to schematically construct the topology of the free energy landscape about the local free energy minima for each of the products.

Results from solvophobic theory applied to methylene selectivity in reversed-phase HPLC

ABSTRACTA significant amount of work has been previously dedicated to the understanding of methylene selectivity parameter. The conventional theory applied for this understanding was mostly based on the assumption that the difference in the Gibbs free energy of transfer from the mobile phase to the stationary phase is a constant for any two compounds in a homologous series that differ by a CH2 group. In the present study, it is shown based on solvophobic theory that this assumption is indeed correct, but it provides a theoretical justification for it. Exemplification of the results of theory was obtained using the values for methylene selectivity (α(CH2)) measured experimentally for seven different C18 chromatographic columns including two core–shell columns and using water and either methanol or acetonitrile as an organic component. Four different homologous series of compounds were used for evaluation. The study proved the theoretical prediction that the values for α(CH2) obtained using different homologous series of compounds are only slightly different from those obtained using the toluene–butylbenzene series. Even using different homologous series, the same type of information regarding the columns comparison, and the changes in log α(CH2) with the solvent composition was obtained.

Phase Ratio and Equilibrium Constant in RP-HPLC Obtained from Octanol/Water Partition Constant Through Solvophobic Theory

The experimentally known dependence in RP-HPLC of the retention factor k′ on octanol/water partition coefficient (K ow) has been examined based on solvophobic theory. The result showed that the dependence provides a means for the evaluation of phase ratio (Φ) of RP-HPLC columns, and of the equilibrium constant for a given compound and mobile phase. Using this theory, the phase ratio was evaluated for a set of seven different C18 columns (five having fully porous particles and two core–shell particles), and the equilibrium constants were calculated for four homologous series of compounds in two mobile phase systems. One mobile phase was methanol/aqueous solution of 0.1% H3PO4, and the other was acetonitrile/aqueous solution of 0.1% H3PO4. Besides providing the values for Φ for the evaluated columns, the results of the study indicated that for a specific composition of the mobile phase and for a given compound displaying only hydrophobic interactions, the equilibrium constant K(X) for different C-18 columns is basically the same. The data were further used to provide guidance in the selection of a chromatographic column for a specific separation based on K ow values and chemical structure of the analytes. The study indicated that the separation of compounds with identical polar groups (or no polar groups) and with very close values for the K ow cannot be achieved based only on hydrophobic interactions that dominate the separation on RP-type columns. Only column that displays polar interactions may provide a solution to such separations. For hydrocarbons with close K ow values, the separation cannot be achieved even on columns with some polarity. On the other hand, even compounds with equal K ow values, but with different functionalities can be separated on RP-HPLC columns without involving polar interactions. The compounds with different K ow values are expected to be easily separated on RP-HPLC columns.

Fractionation of Dissolved Organic Matter on Coupled Reversed-Phase Monolithic Columns and Characterisation Using Reversed-Phase Liquid Chromatography-High Resolution Mass Spectrometry

Eleven Onyx monolithic C18 columns (100 x 3 mm) were connected in series to obtain a high-capacity reversed-phase HPLC column providing 110,000 theoretical plates. The column was used to fractionate a complex mixture of semi-polar and apolar components within marine dissolved organic matter (DOM), isolated using solid-phase extraction (SPE) on poly(styrene–divinylbenzene) cartridges, and Suwannee River natural organic matter, isolated by reverse osmosis. In each case, 15 isolated fractions were further separated using a second-dimension reversed-phase HPLC coupled with high-resolution mass spectrometry. Successful fractionation of the major compositional materials within DOM (i.e. carboxylic-rich alicyclic molecules, CRAM) in order of decreasing polarity was confirmed. Upon formulae assignment, homologous series of compounds were fractionated according to decreasing O/C ratio and increasing H/C ratio. Different compounds with the same exact masses were separated across six fractions, highlighting the immensely complex nature of the material, with the presence of potentially hundreds of molecules for each molecular formula. Both samples showed clear compositional differences not only related to source (seawater or freshwater), but also to the extraction method applied (SPE or reverse osmosis).

Взаимосвязь энергии Гельмгольца с температурой вспышки веществ в гомологическом ряду н-алкиламинов

Взаимосвязь энергии Гельмгольца с температурой вспышки веществ в гомологическом ряду н-алкиламинов

Electroantennographic responses of red flour beetle Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) to volatile organic compounds

AbstractThe red flour beetle Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) is the most encountered and destructive stored product insect pest of cereal grains and seeds. Although this beetle has been used as a model organism for many decades, there is no systematic knowledge about antennal detection of host and non‐host volatiles. Electroantennogram responses to 94 selected volatile organic compounds including alkanes, alkenes, alcohols, aldehydes, ketones, carboxylic acids, esters, terpenoids and aromatic compounds were recorded from both sexes of T. castaneum. Overall, female and male T. castaneum exhibited similar electroantennography (EAG) responses. Compounds eliciting the strongest EAG responses within compound groups of chemical similarity were undecane, 1‐hexen‐3‐ol, octanal, 2‐heptanone, hexanoic acid and ethyl hexanoate. Comparison of vapour pressure and EAG amplitudes within homologous series of compounds revealed responses to undecane, octadecane, octanal, nonanal, 2‐heptanone, hexanoic acid and octanoic acid as outstanding. Given that systematic EAG screenings have not been conducted before, these are the best candidates for evaluation in future behavioural studies to unravel their potential for application in integrated pest management strategies of T. castaneum.

Unexpected retention and efficiency behaviors in supercritical fluid chromatography: A thermodynamic interpretation

Experimental conditions leading to unexpected shift in retention, band compression, and to band enlargement of small molecules in supercritical fluid chromatography are reported. The stationary phase is a 3.0mm×150mm column packed with 1.8μm fully porous high strength silica (HSS) StableBond (SB) C18 particles. The mobile phase is pure carbon dioxide preheated at 107°C and the column back pressure is set at 100bar. The column was thermally insulated in a vacuum chamber at a pressure of 10−5Torr in order to maintain the integrity of the peak symmetry. The sample solution was prepared by dissolving seven n-alkylbenzenes (from benzene to dodecylbenzene) in pure acetonitrile. The injected sample volume (1μL) was three orders of magnitude smaller than the column volume. Remarkably, the retention time of octylbenzene is found 15% smaller than that expected for this series of homologous compounds. Most strikingly, the plate counts change from about 20000 for the three least retained analytes (benzene, ethylbenzene, and butylbenzene) to 60000 for hexylbenzene and to only 5000 for the three most retained compounds (octylbenzene, decylbenzene, and dodecylbenzene). These unexpectedly high (reduced plate height of 1.3) and low (reduced plate height of 15) column efficiencies observed for closely related compounds are consistent with the overlap between the spatial concentration zone of the sample solvent (acetonitrile, Langmuir isotherm, k≃2) and those of the analytes (competitive linear isotherms, 0<k<10). The present observations are fully supported by chromatogram simulations which assume that the Henry's constants of the infinitely diluted analytes are strongly dependent on the concentration of the sample solvent in the mobile phase.

Chemical characterisation of total suspended particulate matter from a remote area in Amazonia

This research had as study object the total suspended particulate matter collected in the Alenquer region, a remote area in the Pará state. The main objectives were the characterisation of the inorganic and organic chemical composition of the aerosol, looking for seasonal patterns and the identification of probable emission sources and formation processes. A set of 30 samples were collected in the rainy (April–May) and dry season (August–September) of 2014. The analytical methods included gravimetric analysis, water-soluble ions analysis by ion chromatography (IC), elemental analysis by inductively coupled plasma mass spectrometry (ICP-MS) equipped with collision cell technology, carbonaceous content determination with a thermal-optical system and organic speciation by gas chromatography–mass spectrometry (GC–MS). The average concentrations of particulate matter ranged from 14±1.3μg·m−3 to 31±7.8μg·m−3, in the rainy and dry season, respectively. The carbonaceous content represented, on average, approximately 27% and 21% of the particulate matter in the rainy and dry season, respectively. Na+, Cl−, SO₄2−, and NO₃− yield the highest concentrations in both seasons. Na was the dominant element, reflecting the transport of air masses from the Atlantic. An increase in concentrations between the rainy and dry seasons was especially noted for the terrigenous elements such Mn, Fe and Al. The chromatographically resolved organics included n-alkanes, n-alkenes, PAHs, n-alkanoic acids, n-di-acids, resin acids and some phenolic compounds. The primary inputs of organic constituents to the aerosols of Alenquer based on the homologous compound series and biomarkers were: (i) natural emissions from terrestrial higher plants waxes, particularly in dry season; (ii) anthropogenic emissions from diesel fuel combustion and biomass combustion, predominating during the dry season. The chemical characterisation along with the backward trajectory cluster analysis suggests a great influence from natural sources such as marine aerosol, mainly in the rainy season. In the dry season, the region is also affected by soil dust re-suspension and some biomass burning.

Enhanced liquid crystal properties in symmetric ethers containing the oxazepine core: synthesis and characterization of seven member heterocyclic dimers

Four new series of symmetric dimers derived from the basic heterocyclic oxazepine core were designed, synthesized, characterized and investigated for liquid crystal properties. The chemical structures of the prepared molecules were characterized by infrared, 1H/13C nuclear magnetic resonance spectra and elemental analysis. Thermal properties and mesophase textures were evaluated by using a combination of differential scanning calorimetry and polarized optical microscopy techniques. Most of the compounds exhibited monotropic liquid crystalline phases in cooling processes. The effect of the spacer chain length and terminal alkoxy chain were studied for the influence on the type of mesophase formed by the homologous series of compounds. Lower members possessing the methylene spacer and a terminal alkoxy-chain favoured smectogenic properties; those derived from medium methylene spacer with terminal alkoxy chain favoured nematogenic properties whereas molecules derived with a higher methylene spacer with terminal alkoxy chain members did not favour any liquid crystalline properties.

Взаимосвязь энергии гельмгольца с температурой вспышки веществ в гомологических рядах н-алкилэтаноатов, н-спиртов и кетонов

The number of organic compounds exceeded 20 million and increases each year by 300 thousand. To ensure the fire safety and technological calculations of processes of production, for storage and transportation materials there are needed data rates fire and explosion hazard substances. To elucidate how the thermodynamic properties of liquid compounds are related to their molecular characteristics, it is necessary to study the properties of compounds in homologous series. The available methods for calculating the properties of multi component systems are also based on the properties of the constituent components. As objects of research there were selected substances homologous series of n-alkyletanoats, aliphatic ketones and alcohols. At various temperatures vapor pressure and density of the liquids in the homologous series were measured. Lewis-Randal calculations do not allow us to directly relate the thermodynamic function values of substances to the molecular weight (structure) of chemical substance. As a reference for calculating the contributions from intermolecular interaction, we used an ideal gas at the temperature, volume of a real liquid and obeying the same statistics. Based on experimental data and using the standard of ideal gas (taken at the temperature and volume of liquid) there are calculated the values internal energy, entropy, and Helmholtz energy. The analysis determined that values of thermodynamic functions are linearly dependent on the molecular weight of the substance in the homologous series. Analysis of published data established as a linear dependence of the flash point of substances of molecular weight substances in the homologous series. Considering the tendency of change these properties it's established that the flash point of substances linearly dependent on the values of the energy of Helmholtz of substances homologous series. The corresponding equations were obtained. The established regularities and obtained based on these equations allow us to predict the properties of homologous series of substances with the necessary accuracy for practical purposes.

Ester Modified Pyrrolidinium Based Ionic Liquids as Electrolyte Component Candidates in Rechargeable Lithium Batteries

AbstractRoom temperature ionic liquids (RTILs), especially pyrrolidinium based RTILs with bis(trifluoromethane‐sulfonyl)imide (TFSI) as counterion, are frequently proposed as promising electrolyte component candidates thanks to their high thermal as well as high oxidation stability. In order to avoid a resource intensive experimental approach, mainly based on trial and error experiments, a computational screening method for pre‐selecting suitable candidate molecules was adopted and three homologous series compounds were synthesized by modifying the cation structure of pyrrolidinium RTILs. The obtained high purity RTILs: methyl‐methylcarboxymethyl pyrrolidinium TFSI (MMMPyrTFSI), methyl‐ethylcarboxymethyl pyrrolidinium TFSI (MEMPyrTFSI) and methylpropylcarboxymethyl pyrrolidinium TFSI (MPMPyrTFSI) revealed excellent thermal stabilities higher than 300 °C. Furthermore, MMMPyrTFSI and MPMPyrTFSI exhibit high oxidation stability up to 5.4 V vs. Li/Li+. No aluminum corrosion of current collector was observed at 5 V vs. Li/Li+. In addition to that, these RTILs display a superior salt (LiTFSI) solubility (3.0–3.5 M), compared to the unmodified RTIL 1‐butyl‐1‐methylpyrrolidinium TFSI (Pyr14TFSI) (1.5–2.0 M) at room temperature. All these properties make novel ester modified RTILs promising and interesting candidates for application in rechargeable lithium batteries.

Identification of Novel Perfluoroalkyl Ether Carboxylic Acids (PFECAs) and Sulfonic Acids (PFESAs) in Natural Waters Using Accurate Mass Time-of-Flight Mass Spectrometry (TOFMS).

Recent scientific scrutiny and concerns over exposure, toxicity, and risk have led to international regulatory efforts resulting in the reduction or elimination of certain perfluorinated compounds from various products and waste streams. Some manufacturers have started producing shorter chain per- and polyfluorinated compounds to try to reduce the potential for bioaccumulation in humans and wildlife. Some of these new compounds contain central ether oxygens or other minor modifications of traditional perfluorinated structures. At present, there has been very limited information published on these "replacement chemistries" in the peer-reviewed literature. In this study we used a time-of-flight mass spectrometry detector (LC-ESI-TOFMS) to identify fluorinated compounds in natural waters collected from locations with historical perfluorinated compound contamination. Our workflow for discovery of chemicals included sequential sampling of surface water for identification of potential sources, nontargeted TOFMS analysis, molecular feature extraction (MFE) of samples, and evaluation of features unique to the sample with source inputs. Specifically, compounds were tentatively identified by (1) accurate mass determination of parent and/or related adducts and fragments from in-source collision-induced dissociation (CID), (2) in-depth evaluation of in-source adducts formed during analysis, and (3) confirmation with authentic standards when available. We observed groups of compounds in homologous series that differed by multiples of CF2 (m/z 49.9968) or CF2O (m/z 65.9917). Compounds in each series were chromatographically separated and had comparable fragments and adducts produced during analysis. We detected 12 novel perfluoroalkyl ether carboxylic and sulfonic acids in surface water in North Carolina, USA using this approach. A key piece of evidence was the discovery of accurate mass in-source n-mer formation (H(+) and Na(+)) differing by m/z 21.9819, corresponding to the mass difference between the protonated and sodiated dimers.

Dipolar origin of tilting of rod-like molecules in the smectic C phase

We review various proposed molecular mechanisms for tilting of rod-like molecules in the smectic C phase. We analyse some experimental results, viz. (1) unusual odd–even effects in smectic A to nematic (TAN) and smectic A to smectic C (TAC) transition temperatures and/or maxima in TAC in some homologous series of compounds, (2) occurrence of re-entrant SmA and/or hexatic SmB as lower temperature phases, (3) SmC replaced by SmA when a halogen atom is substituted at the end of one of the chains, (4) suppression of SmC phase at high pressures, and in binary mixtures with dissimilar aromatic cores or chain lengths, (5) induction of SmC phase in mixtures of some structural isomers and (6) some recent all-atom simulations. The results can be understood on the basis of our molecular theory in which the tilting occurs due to the repulsive coulomb interaction between neighbouring molecules having off-axis dipoles with transverse components and freely rotating about their long axes in smectic layers. The model also takes into account the entropic cost of tilting which depends on the length to width ratio of the molecules. We have included some simple calculations of the induced dipoles in the chains to account for the odd–even effects.

Isolation and identification of cyclic lipopeptides from Paenibacillus ehimensis, strain IB-X-b.

Antifungal lipopeptides produced by an antagonistic bacterium, Paenibacillus ehimensis strain IB-X-b, were purified and analyzed. The acetone extract of the culture supernatant contained an antifungal amphiphilic fraction stainable with ninhydrin on thin layer chromatography. The fraction was further purified with water-methanol extraction followed by a chromatography on a C18-support. The analysis with LC-MS showed presence of two main series of homologous compounds, family of depsipeptides containing a hydroxy fatty acid, three 2,4-diaminobutyric acid (Dab) residues, five hydrophobic amino acids and one Ser/Thr residue, and cyclic lipopeptides of bacillomycin L and fengycin/plipastatin/agrastatin families. The prevailing compounds in this group are bacillomycin L-C15, fengycin/plipastatin A-C16 together with their homologues responsible for the majority of fungal growth inhibition by P. ehimensis IB-X-b.

Molecular Dyads of Ruthenium(II)– or Osmium(II)–Bis(terpyridine) Chromophores and Expanded Pyridinium Acceptors: Equilibration between MLCT and Charge-Separated Excited States

The synthesis, characterization, redox behavior, and photophysical properties (both at room temperature in fluid solution and at 77 K in rigid matrix) of a series of four new molecular dyads (2-5) containing Ru(II)- or Os(II)-bis(terpyridine) subunits as chromophores and various expanded pyridinium subunits as electron acceptors are reported, along with the reference properties of a formerly reported dyad, 1. The molecular dyads 2-4 have been designed to have their (potentially emissive) triplet metal-to-ligand charge-transfer (MLCT) and charge-separated (CS) states close in energy, so that excited-state equilibration between these levels can take place. Such a situation is not shared by limit cases 1 and 5. For dyad 1, forward photoinduced electron transfer (time constant, 7 ps) and subsequent charge recombination (time constant, 45 ps) are evidenced, while for dyad 5, photoinduced electron transfer is thermodynamically forbidden so that MLCT decays are the only active deactivation processes. As regards 2-4, CS states are formed from MLCT states with time constants of a few dozens of picoseconds. However, for these latter species, such experimental time constants are not due to photoinduced charge separation but are related to the excited-state equilibration times. Comparative analysis of time constants for charge recombination from the CS states based on proper thermodynamic and kinetic models highlighted that, in spite of their apparently affiliated structures, dyads 1-4 do not constitute a homologous series of compounds as far as intercomponent electron transfer processes are concerned.

Solubility enhancement and QSPR correlations for polycyclic aromatic hydrocarbons complexation with α, β, and γ cyclodextrins

Through batch equilibrium experiments, hydroxypropyl substituted α, β, and γ cyclodextrin (CDs) were shown to greatly increase the apparent solubility of eight common polycyclic aromatic hydrocarbons (PAHs) in aqueous solutions. Equations based on the volume fraction of solution composed of water and CDs have been developed to determine guest phase distribution. Based on these equations, the results of this and similar studies for CD showed that a log–log relationship exists between the fraction of CD occupied with a guest organic compound and the aqueous solubility of those guests (rsq 0.980). Analysis of potential quantitative structure property relationship (QSPR) found strong correlations between structural properties of the guests (e.g. aqueous solubility, octanol/water partitioning coefficient, molar volume, molecular surface area, and polarizability) and water/CD partitioning coefficients, phase distribution of the PAH between water and CD phases, and the fraction of CD molecules occupied with a guest PAH. Noteworthy among these, is the inverse relationship between the log of the fraction of CD molecules occupied under saturated conditions and the ratio of the molar volume of the PAH to the volume of the CD cavities (rsq for α, β, and γ: 0.887–0.892). Comparisons of the three CDs shows that while the size of the guest compound reduces its propensity to enter into the CD cavity, the effect of the guest size is lessened as the width of the CD ring increases. Development of these QSPR correlations provides a means to predict and evaluate guest/CD interactions for homologous series of compounds.

Gas chromatographic retention of alkyl phosphates on ionic liquid stationary phases

Retention behaviors of alkyl phosophates were studied on a series of ionic liquid gas chromatography columns. The selectivity of the IL columns for alkyl phosphates were compared with a 5% phenyl column as a route to evaluating the potential use of IL columns in the analysis of alkyl phosphates in petroleum samples in both one- and multi-dimensional GC. Most interestingly, we demonstrate for the first time the dependence of elution order on separation temperature for members of a homologous series of compounds. At low temperatures it was found that trihexyl phosphate eluted before trioctyl phosphate, while at higher temperatures this pattern was reversed.

A Homologous Series of First-Row Transition-Metal Complexes of 2,2′-Bipyridine and their Ligand Radical Derivatives: Trends in Structure, Magnetism, and Bonding

The organometallic first-row transition-metal complexes [M(2,2'-bipy)(mes)2] (M = Cr (1), Mn (2), Co (4), Ni (5); 2,2'-bipy = 2,2'-bipyridine; mes = 2,4,6-Me3C6H2) were reacted with potassium and a suitable alkali-metal sequestering agent to yield salts of the anionic species [M(2,2'-bipy)(mes)2](-). The neutral parent compounds and their corresponding anionic congeners were characterized by single-crystal X-ray diffraction in [Cr(2,2'-bipy)(mes)2]·1.5C6H6, [Mn(2,2'-bipy)(mes)2], [Co(2,2'-bipy)(mes)2]·THF, [Ni(2,2'-bipy)(mes)2], [K(dibenzo-18-crown-6)·THF][Cr(2,2'-bipy)(mes)2]·2THF, [K(18-crown-6)][Mn(2,2'-bipy)(mes)2]·2THF, [K(18-crown-6)][Mn(2,2'-bipy)(mes)2]·0.67py·0.67tol, [K(2,2,2-crypt)][Co(2,2'-bipy)(mes)2], and [K(2,2,2-crypt)][Ni(2,2'-bipy)(mes)2]. These species, along with the previously reported neutral and anionic iron complexes [Fe(2,2'-bipy)(mes)2](0/-) (3/3(-)), form a homologous series of compounds which allow for an in-depth study of the interactions between metals and ligands. Single-crystal X-ray diffraction data, DFT calculations, and various spectroscopic and magnetic measurements indicate that the anionic complexes (1(-)-5(-)) can be best formulated as M(II) complexes of the 2,2'-bipyridyl radical anion. These findings complement recent studies which indicate that bond metric data from single-crystal X-ray diffraction may be employed as an important diagnostic tool in determining the oxidation states of bipyridyl ligands in transition-metal complexes.

Novel product ions of 2-aminoanilide and benzimidazole Ag(I) complexes using electrospray ionization with multi-stage tandem mass spectrometry

The 2-aminoaniline scaffold is of significant value to the pharmaceutical industry and is embedded in a number of pharmacophores including 2-aminoanilides and benzimidazoles. A novel application of coordination ion spray mass spectrometry (CIS-MS) for interrogating the silver ion (Ag(+)) complexes of a homologous series of these compounds using multi-stage tandem mass spectrometry is described. Unlike the ubiquitous alkali metal ion complexes, Ag(+) complexes of 2-aminoanilides and benzimidazoles were found to yield [M - H](+) ions in significant abundance via gas-phase elimination of the metal hydride (AgH) resulting in unique product ion cascades. Sample introduction was by liquid chromatography with mass spectrometry analysis performed on a hybrid linear ion trap/orbitrap instrument capable of high-resolution measurements. Rigorous structural characterization by multi-stage tandem mass spectrometry using [M + H](+), [M - H](-) and [M - H](+) precursor ions derived from ESI and CIS experiments was performed for the homologous series of 2-aminoanilide and benzimidazole compounds. A full tabular comparison of structural information resulting from these product ion cascades was produced. Multi-stage tandem mass spectrometry of [M - H](+) ions resulting from Ag(+) complexes of 2-aminoanilides and benzimidazoles in CIS-MS experiments produced unique product ion cascades that exhibited complementary structural information to that obtained from tandem mass spectrometry of [M + H](+) and [M - H](-) ions by electrospray ionization (ESI). These observations may be broadly applicable to other compounds that are observed to form Ag(+) complexes and eliminate AgH.