Methodology gaps in Chemistry

Representative open questions

Showing 30 of 101 — one per source paper, highest-quality first.

• Ultrasound-assisted adsorption of congo red dye using green synthesized silver nanoparticles coated with chitosan (2026) · doi

  Although the study uses green synthesis of silver nanoparticles from plant materials, it does not compare the adsorption performance of Chi-AgNPs synthesized using different plant precursors or evaluate how variations in the green synthesis protocol (extraction method, reaction time, temperature) influence the final adsorbent's dye removal capacity.

• Jellyfish bioactive compounds fueling marine biotechnology in blue economy and biomedicine (2026) · doi

  Supercritical fluid extraction and deep eutectic solvents have been proposed for jellyfish bioactive compound extraction, but no direct comparative studies quantifying extraction efficiency, bioactive compound yield, and cost-effectiveness between these methods and conventional extraction protocols for jellyfish tissues have been conducted.

• Mechanistic investigations of the formation of multifunctional products from the multi-generation ●OH oxidation of styrene (2026) · doi

  The fractional yields for second and third generation closed-shell products vary significantly (e.g., S26: 4.8%, S47: 26.3%, S62: 0.03%); systematic sensitivity analysis examining how experimental conditions (temperature, pressure, NOx concentration, humidity) affect these yield distributions has not been performed.

• High-Entropy Catalysts for Biomass-Derived Chemicals Valorization: Mechanisms, Applications, and Opportunities (2026) · doi

  Structure design strategies developed for high-entropy catalysts in hydrogen oxidation reactions (such as HEA aerogels with 3D interconnected open channels and nanoscale distorted structures) have not been systematically transplanted to or validated for biomass valorization reactions. The correlation between aerogel morphology, macroscale nanoscale property retention, and catalytic performance in glucose and glycerol conversion requires experimental investigation.

• QM/MM hybrid simulation of enzyme-Mn synergistic catalysis for quinazolinones: computational determination of activation energy and transition state (2026) · doi

  The activation energy calculations revealed that Mn²⁺ charge state exhibits optimal catalytic activity, but the electronic state matching mechanism between the metal center and enzyme active pocket electrostatic environment was not quantitatively characterized; detailed QTAIM or NBO analysis of electron density redistribution at different Mn charge states (+1, +2, +3) is needed.

• A critical review of the production pathways and storage limitations and economic feasibility of green hydrogen fuel (2026) · doi

  Oxygen-tolerant hydrogenases for biological hydrogen production pathways have not been developed to close the existing 80% yield gap in current algal-based green hydrogen systems. Research is needed to engineer hydrogenase variants that can operate efficiently in the presence of oxygen to improve the practical viability of biological hydrogen generation.

• The role of the bis-trimethylsilylamido ligand, [N{SiMe3}2]−, in main group chemistry. Part 1: Structural chemistry of the s-block elements (2015) · doi

  The source of oxygen contamination in the synthesis of compound 250 containing μ-N{SiMe3}2 was reproducibly traced to THF solvent rather than atmospheric sources, but systematic investigation of THF oxidation pathways under specific reaction conditions (temperature, concentration, metal combinations) with the bis-trimethylsilylamido ligand has not been conducted.

• Functional nanocomposites for energy storage: chemistry and new horizons (2020) · doi

  Replacing carbon with group 14 elements in polymer chains to tailor ionic polarization shows theoretical promise but presents significant synthesis challenges; the specific synthetic routes, reaction conditions, and scalability barriers for producing such modified polymers for nanocomposite capacitors remain unaddressed.

• Cyclooligophosphanes and their coordination chemistry (2021) · doi

  While catalytic dehydrocoupling methods for primary phosphines are established with iron(II), zirconium, and N-heterocyclic carbene mediators (references 39, 44, 45, 43), the selectivity and regioselectivity of cyclophosphane ring closure when using substituted phosphines with mixed organic groups (alkyl/aryl combinations) has not been systematically investigated.

• Christmas chemistry A–Z (2014) · doi

  The vanilla section notes a 100-fold discrepancy between natural vanilla extraction (100t/year) and global demand (20,000t/year), with most being chemically synthesized, but does not investigate the specific chemical synthesis pathways used commercially or compare the sensory/chemical profile differences between naturally extracted and synthetically produced vanillin at equivalent concentrations.

• Olympian colour chemistry (2012) · doi

  Multi-dye formulations for achieving neutral grey and brown lens shades require balancing up to six different photochromic dyes with complementary absorption spectra and kinetics. The paper lacks systematic guidelines for predicting which combinations of dihetarylethene, spirooxazine, and naphthopyran structural modifications (electron donor positioning, halogen substitution, alkoxy/amino groups) will optimize neutral colour without fatigue or kinetic mismatches.

• WITHDRAWN: Combinatorial Chemistry Online Volume 15, Issue 11, November 2013 (2013) · doi

  The iterative ligation approach for polypeptide synthesis using bis(2-sulfanylethyl)amido (SEA) peptide segments reported by Raibaut et al. has demonstrated efficiency for large polypeptides, but systematic optimization of coupling efficiency, segment length constraints, and compatibility with post-translational modifications in combinatorial contexts is absent.

• Transmetallation Reaction of Alkali and Alkaline-earth Metal Ions in Supramolecular Complex of [{Au6Cd3(tdme)2(D-pen)6}Cd4Na4](NO3)12 (2026) · doi

  The study only examined transmetallation reactions with alkali metals (Na, K, Cs) and alkaline-earth metals (Sr) in the supramolecular Au₆Cd₃ cage framework. Transmetallation behavior with transition metal ions possessing accessible d-orbitals (e.g., Zn²⁺, Cu²⁺, Ni²⁺) at the metal-linker position should be systematically investigated to test whether d-orbital availability enables substitution at the coordinate CdII centers.

• Synthesis of Tetravalent Boron Complexes with Pyrazolone-Based Ligand and their Drug-Likeness (2026) · doi

  The synthesis and characterization of tetravalent boron complexes with 2-isopropoxy-1,3,2-benzodioxaborole and 5-methyl-2-phenyl-4-(2-phenylhydrazinylidene)-2,4-dihydro-3H-pyrazol-3-one was reported, but metabolic stability studies using liver microsomes or recombinant cytochrome P450 enzymes were not conducted to assess phase I/II biotransformation pathways of these specific boron-pyrazolone coordination compounds.

• Physical Organic Chemistry (POC) Makes Chemistry a Science: A Personal Reflection on POC (2016) · doi

  The Big Data approach for chemical discovery is proposed conceptually but lacks concrete implementation details for chemistry datasets. Specific protocols are needed for mining historical chemical databases, literature archives, and synthesis records to identify previously unobserved correlations and cause-effect relationships in organic reaction mechanisms.

• The advent of macrocyclic chemistry (2012) · doi

  While the paper identifies that intra-ligand repulsions are smaller for cyclic secondary amines enabling shorter metal-nitrogen distances, it does not provide quantitative measurements or comparative bond length data across different macrocyclic structures to establish structure-property relationships.

• Analytical Techniques in Chemistry (2019) · doi

  Buffer tablets are mentioned as commercially available for pH meter standardization (pH 4, 7, 9.2), but the paper lacks specification of the shelf-life stability, hydration requirements, and accuracy comparison between buffer tablets and freshly prepared buffer solutions from Tables 25.3 and 25.4 reagents.

• Basic Organometallic Chemistry (2016) · doi

  The paper describes tetrameric and hexameric forms of methyllithium identified through NMR and crystallography, but does not explore the kinetic stability or interconversion mechanisms between these oligomeric forms under different solvent and temperature conditions.

• The Basis of a Greener Analytical Chemistry (2011) · doi

  On-line decontamination processes and end-pipe treatments for mechanized methods are identified as critical for handling toxic analytical wastes from metal and pesticide analyses, but the paper provides no specific protocols, efficiency data, or comparisons of different decontamination strategies for different waste types.

• Initial organotin chemistry (2014) · doi

  The mechanism of polystannane degradation under light exposure to form cyclic oligostannanes from [(C2H5)2Sn]n has not been experimentally validated or quantified; the specific wavelength dependencies and degradation kinetics require investigation.

• Chemistry of Carbon and Hydrogen (2019) · doi

  The reducing action of carbon (Section 26.12) presents four reduction reactions with metallic oxides, steam, sulphates, and acids, but does not characterize the reaction kinetics, temperature dependencies, catalyst requirements, or competitive pathways when multiple substrates are present in industrial metallurgical operations.

• Bis (N-Heterocyclic Carbene) Palladium Complex Immobilized Onto Fe3o4@Sio2 as a Catalyst for Sonogashira (Amine/Copper Free) and Hiyama Coupling of Arbr/Cl in Green Media (2026) · doi

  The catalyst recyclability studies demonstrate efficient reuse up to 6 cycles, but a pronounced efficiency drop occurs at the seventh cycle. The specific mechanism of catalyst deactivation—whether caused by Pd leaching, support degradation, or NHC ligand decomposition—requires investigation to enable extended operational lifetime of the Fe3O4@SiO2-supported Pd-NHC heterogeneous catalyst.

• Coordination chemistry of poly(thioether)borate ligands (2010) · doi

  The mechanism for stepwise formation of [(PhTttBu)Ni]2(μ-O)2 from [PhTttBu]Ni(CO) has been proposed based on optical and EPR spectral evidence of the 1:1 intermediate, but direct kinetic characterization of the dimerization step and quantitative rate constants for the transition from monomeric [PhTttBu]Ni(O2) to dimeric bis-μ-oxo product are lacking.

• Coordination chemistry of tris(azolyl)phosphines (2018) · doi

  The triazolylation reaction using OP(1,2,4Tz)3 has been conducted in three different solvent systems (acetonitrile, dichloromethane, and pyridine) with varying base conditions and product yields (up to 60% in pyridine), but no systematic solvent-base screening or mechanistic investigation has been reported to optimize reaction conditions or understand why pyridine occasionally produces only pyridinium salts as side products.

• My journey in the CO2-chemistry wonderland (2017) · doi

  The carboxylation of racemic epoxide mixtures achieved only moderate enantioselectivity (22% ee) due to deanchoring of the optically active ligand under reaction conditions. The specific mechanisms causing ligand deanchoring during CO2 carboxylation with heterogeneous catalysts using different ring sizes (three-, four-, five-, six-membered ethers) and substituent patterns require systematic investigation.

• Organometallic Chemistry of Heterocycles (2010) · doi

  While fluoropyrrole C—F activation has been documented as a rare event and phosphinopyrrole generates N-heterocyclic carbenes with phosphine donors, the mechanistic pathways governing selective C—F activation over other C—H or N—H bond activations in fluorinated heterocycles remain uncharacterized.

• Resonance-enhanced multiphoton ionization time-of-flight mass spectrometry for the real-time analysis of a retronasal aroma compound from a cumin sandwich (2026) · doi

  The REMPI-TOFMS analysis at 266 nm wavelength selectively detected only p-cymene from cumin; the study requires investigation of whether the logistic function fitting parameters (γ1, γ2, amplitude A1) can be reliably extracted when cumin is mixed with other spices that contain additional aroma compounds ionizable at this wavelength.

• cAMPS derivatives. A minireview over synthetic medicinal chemistry (2019) · doi

  The paper identifies that partial halogen exchange reactions can contaminate elementally pure 8-bromo cAMPS derivatives with corresponding 8-chloro compounds when chloride ions are present in the reaction mixture, but does not specify optimized reaction conditions or additives to selectively suppress halogen exchange and achieve >95% chemical purity without chromatographic purification.

• Multicomponent reactions in crop protection chemistry (2020) · doi

  The Passerini reaction has been applied to generate trifluoromethylated atrolactamide libraries with fungicidal activity, but mechanistic understanding of how isocyanide addition and ring-closure conditions affect stereoselectivity and regioselectivity in this multicomponent sequence remains incomplete.

• Developments in Heterocyclic Microwave Chemistry (2016) · doi

  The microwave-assisted synthesis of 2-amino-2H-chromene-3-carboxylates shows poor yields with electron-donating groups on salicylaldehyde, but the mechanistic reasons for this electronic effect remain unexplored. Systematic investigation of how electron-donating versus electron-withdrawing substituents affect the cycloaddition reaction pathway under microwave irradiation conditions is needed.