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School of Physical and Chemical Sciences

Dr Gregory Chass

Gregory

Director of Graduate Studies and Reader in Computational Chemistry

Email: g.chass@qmul.ac.uk
Telephone: +44 (0)20 7882 5835
Room Number: Room G.04, Joseph Priestley Building

Undergraduate Teaching

  • Essential Skills for Chemists (Tutorials) (CHE100)
  • States of Matter and Analytical Chemistry (CHE108)
  • Physical and Quantum Chemistry (CHE204A)

Postgraduate Teaching

Teaching on our Chemical Research MSc:

  • Computational Chemistry (CHE305U)

Research

Research Interests:

Part of the Chemistry department

Chass Group 

The main topical focus of the Chass research group is the nanoscopic level characterisation and performance optimisation of disordered materials for use in infrastructure, medical and dental applications as well as natural mineralisation processes. The atomistic origins of bulk properties are resolved through a combination of experimental measurements designed through computational simulations, including neutron scattering, muon-spin resonance, free-electron laser, coherent-THz spectroscopy, microscopy imaging and mechanical testing – in a wide range of national and international large-scale research facilities in the UK,

Cements in construction and medical restorationsNeutron Compton Scattering (NCS) derived fracture toughness of a glass-cement over setting time. (Inlay) Wide angle neutron scattered (WANS) structure of cement and its components.

Construction cement is by-far the most manufactured material worldwide and used in progressively wider scopes of applications, including in bone and tooth restorations and as adhesives (i.e. for prosthetics & implants). With more than 4x109 tonnes produced each year cement is also the industry with the single largest CO2 emissions; thus its crucial to develop novel ‘green’ and longer-lasting cements. Despite such extreme production and pollution levels, cement remains one of the most complex and least understood systems, particularly at the atomic level.

Cements in construction and medical restorations Construction cement is by-far the most manufactured material worldwide and used in progressively wider scopes of applications, including in bone and tooth restorations and as adhesives (i.e. for prosthetics & implants). With more than 4x109 tonnes produced each year cement is also the industry with the single largest CO2 emissions; thus its crucial to develop novel ‘green’ and longer-lasting cements. Despite such extreme production and pollution levels, cement remains one of the most complex and least understood systems, particularly at the atomic level. Our work involves formulating novel structural models of the calcium silicate hydrate (C-S-H) gel responsible for the cohesion of the cement components and its bulk mechanical properties. Models are used to design experiments to confirm the structure and properties predicted by the models, with specific focus on the cementation mechanism and kinetics. The novelty in our approache involves accurately tracking of dynamical changes in structure, atomic kinetic energies and collective atomic (terahertz) motions over setting time (Fig.1), and up to 2 years. These results are then related to the performance metrics used by engineers and industry, (eg. fracture toughness, young’s modulus of elasticity), towards informing on the optimisation & design of novel cements.

Mineralisations of bone, tooth and CO2 emissionsTransmission electron microscopy of a glass cement used to restore & remineralise tooth structure. 3 distinct phases with differing size ranges and glass transition temperatures were identified.

As with the structural and phase-changes ongoing in cements, natural mineralisations are also studied in a similar manner, through the formulation of a synergy between experiment and computer simulation. The systems and phenomena of current foci include remineralisation of bone and teeth (Fig.2) by various cements (eg. glass cements, resin-cements), as well as the catalysing effect of additives from organic sources and/or inorganic salts.

This work has most recently led to collaborative work on the mineralisation of industrial CO2 emissions to produce profitable solid mineral products for use as fillers in green cements as well as in fertilizers. Further work is also underway on the use of waste ‘slags’ from steel production and from agriculture (non-alimentary fibres & starches) as cement fillers and additives towards lowering their ecological footprints (and costs) whilst raising performance.

Publications

    • Toroz D, Song FV, Chass GA et al. (2021), New insights into the role of solution additive anions in Mg2+ dehydration: implications for mineral carbonation $nameOfConference


    • Liu H, Chen W, Pan R et al. (2020), From Molten Calcium Aluminates through Phase Transitions to Cement Phases $nameOfConference


    • Fianchini M, O'brien CJ, Chass GA (2019), Reduction rate of 1-phenyl phospholane 1-oxide enhanced by silanol byproducts: Comprehensive DFT study and kinetic modeling linked to reagent design $nameOfConference


    • Tian KV, Passaretti F, Nespoli A et al. (2019), Composition—nanostructure steered performance predictions in steel wires $nameOfConference


    • Zhang X, Alvarez-Lloret P, Chass GA et al. (2019), Interatomic potentials of mg ions in aqueous solutions: Structure and dehydration kinetics GMDM 2018


    • Mu WH, Cheng RJ, Fang DC et al. (2018), The pivotal role of electronics in preferred alkene over alkyne Ni-carboryne insertions and absolute regioselectivities $nameOfConference


    • Tian KV, Chass G, Di Tommaso D (2017), Simulations reveal the role of composition into the atomic-level flexibility of bioactive glass cements $nameOfConference

    • Mu WH, Fang DC, Xia SY et al. (2016), Multi-Pathway Consequent Chemoselectivities of CpRuCl(PPh3)2/MeI-Catalysed Norbornadiene Alkyne Cycloadditions $nameOfConference


    • Tian KV, Mahmoud MZ, Cozza P et al. (2016), Periodic vs. molecular cluster approaches to resolving glass structure and properties: Anorthite a case study $nameOfConference


    • Zhu X, Chass GA, Kwek LC et al. (2015), Excitonic Character in Optical Properties of Tetrahedral CdX (X = S, Se, Te) Clusters $nameOfConference


    • Tian T, Chass G, DI TOMMASO D (2015), Simulations Reveal the Role of Composition into the Atomic-Level Flexibility of Bioactive Glass Ionomer Cements $nameOfConference


    • Tian KV, Yang B, Yue Y et al. (2015), Atomic and vibrational origins of mechanical toughness in bioactive cement during setting $nameOfConference


    • Mu WH, Xia SY, Li JX et al. (2015), Competing Mechanisms, Substituent Effects, and Regioselectivities of Nickel-Catalyzed [2 + 2 + 2] Cycloaddition between Carboryne and Alkynes: A DFT Study $nameOfConference


    • Jenkins S, Xiao CX, Xu T et al. (2015), Quantum topological resolution of catalyst proficiency $nameOfConference


    • Pedersen MT, Tian KV, Dobó-Nagy C et al. (2015), Phase separation in an ionomer glass: Insight from calorimetry and phase transitions $nameOfConference


    • Bennett E, Wilson T, Murphy PJ et al. (2015), How the surface structure determines the properties of CuH $nameOfConference


    • Donnan R, Tian KV, Yang B et al. (2015), The power of VNA-driven quasi-optics to sense group molecular action in condensed phase systems $nameOfConference


    • Jenkins S, Xiao C-X, Xu T et al. (2015), Quantum topological resolution of catalyst proficiency $nameOfConference


    • Bennett EL, Wilson T, Murphy PJ et al. (2015), Structure and spectroscopy of CuH prepared via borohydride reduction $nameOfConference


    • Chen Y-M, Chass GA, Fang D-C (2014), Between a reactant rock and a solvent hard place--molecular corrals guide aromatic substitutions. $nameOfConference


    • Andreani C, Ceriotti M, Chass G et al. (2014), Discussion: Nuclear quantum dynamics - Protons and beyond $nameOfConference


    • Mucsi Z, Chass GA, Ábrányi-Balogh P et al. (2013), Penicillin's catalytic mechanism revealed by inelastic neutrons and quantum chemical theory. $nameOfConference


    • Lian B, Zhang L, Chass GA et al. (2013), Pd(OAc)2-catalyzed C-H activation/C-O cyclization: mechanism, role of oxidant-probed by density functional theory. $nameOfConference


    • Tao J-Y, Mu W-H, Chass GA et al. (2013), Balancing the atomic waistline: Isodensity-based scrf radii for main-group elements and transition metals $nameOfConference


    • Tao J-Y, Fang D-C, Chass GA (2012), Simplification through complexity: the role of Ni-complexes in catalysed diyne-cyclobutanone [4+2+2] cycloadditions, a comparative DFT study. $nameOfConference


    • Tian KV, Nagy PM, Chass GA et al. (2012), Qualitative assessment of microstructure and Hertzian indentation failure in biocompatible glass ionomer cements $nameOfConference


    • Qin B, Ren CL, Ye RJ et al. (2010), Persistently Folded Circular Aromatic Amide Pentamers Containing Modularly Tunable Cation-Binding Cavities with High Ion Selectivity $nameOfConference


    • Davies RA, Ardalan S, Mu WH et al. (2010), Geometric, electronic and elastic properties of dental silver amalgam gamma-(Ag3Sn), gamma(1)-(Ag2Hg3), gamma(2)-(Sn8Hg) phases, comparison of experiment and theory $nameOfConference


    • Chass GA, Kantchev EAB, Fang D-C (2010), The fine balance between one cross-coupling and two beta-hydride elimination pathways: a DFT mechanistic study of Ni(pi-allyl)(2)-catalyzed cross-coupling of alkyl halides and alkyl Grignard reagents. $nameOfConference


    • Mu WH, Chasse GA, Fang DC (2009), A Synergy between Experiment and Theory for the Formation of Pyridine and Pyrrole Derivatives from Selected Butadienes and Organolithium Reagents: Mechanism, Solvent, and Substituent Effect $nameOfConference


    • Organ MG, Calimsiz S, Sayah M et al. (2009), Pd N-heterocyclic carbene catalysts: How much bigger is better? $nameOfConference

    • Chass GA, Kargl F, Fang DC et al. (2009), The role of bulkiness in promoting Pd-NHC-catalyzed cross-couplings: A synergy between experiment, spectroscopy, and theory $nameOfConference

    • Mucsi Z, Chass GA, Csizmadia IG (2009), Systemic energy management by strategically located functional components within molecular frameworks, determined by systems chemistry. $nameOfConference


    • Wang H, Csizmadia IG, Marsi I et al. (2009), Network of hydrogen bonds in Pro-Ala-Pro and Pro-Phe-Pro diamides: a first principles study of Ala-->Phe point mutation in proline environment. $nameOfConference


    • Mucsi Z, Chass GA, Viskolcz B et al. (2009), A quantitative scale for the extent of conjugation of substituted olefines. $nameOfConference


    • Chass GA, O'Brien CJ, Hadei N et al. (2009), Density functional theory investigation of the alkyl-alkyl Negishi cross-coupling reaction catalyzed by N-heterocyclic carbene (NHC)-Pd complexes. $nameOfConference


    • O'Brien CJ, Tellez JL, Nixon ZS et al. (2009), Recycling the Waste: The Development of a Catalytic Wittig Reaction $nameOfConference


    • Chass GA, Csizmadia IG (2008), Conversion of combustible municipal solid waste to methyl alcohol: An environmentally friendly technology $nameOfConference


    • Mucsi Z, Chass GA, Viskolcz B et al. (2008), Quantitative scale for the extent of conjugation of carbonyl groups: "carbonylicity" percentage as a chemical driving force. $nameOfConference


    • Organ MG, Chass GA, Fang DC et al. (2008), Pd-NHC (PEPPSI) complexes: Synthetic utility and computational studies into their reactivity $nameOfConference


    • Mu WH, Chasse GA, Fang DC (2008), Test and modification of the van der Waals' radii employed in the default PCM model $nameOfConference


    • Mu W-H, Chasse GA, Fang D-C (2008), High level ab initio exploration on the conversion of carbon dioxide into oxazolidinones: the mechanism and regioselectivity. $nameOfConference


    • Mucsi Z, Chass GA, Csizmadia IG (2008), Amidicity change as a significant driving force and thermodynamic selection rule of transamidation reactions. A synergy between experiment and theory. $nameOfConference


    • Mucsi Z, Tsai A, Szori M et al. (2007), A quantitative scale for the extent of conjugation of the amide bond. Amidity percentage as a chemical driving force. $nameOfConference


    • O'Brien CJ, Kantchev EAB, Valente C et al. (2006), Easily prepared air- and moisture-stable Pd-NHC (NHC=N-heterocyclic carbene) complexes: a reliable, user-friendly, highly active palladium precatalyst for the Suzuki-Miyaura reaction. $nameOfConference


    • O'Brien CJ, Kantchev EAB, Chass GA et al. (2005), Towards the rational design of palladium-N-heterocyclic carbene catalysts by a combined experimental and computational approach $nameOfConference


    • Chun CP, Connor AA, Chass GA (2005), Ab initio conformational analysis of N- and C-terminally-protected valyl-alanine dipeptide model $nameOfConference


    • Hadei N, Kantchev EAB, O'Brien CJ et al. (2005), Rational catalyst design and its application in sp(3)-sp(3) couplings $nameOfConference

    • Chasse G, Hopkinson AC, Kantchev EAB et al. (2005), Towards a computed structure database: Modular and systematic approach to develop effective Pd-N-heterocyclic carbene catalysts for cross-coupling reactions $nameOfConference

    • Chass GA, Mirasol RS, Setiadi DH et al. (2005), Characterization of the conformational probability of N-acetyl-phenylalanyl-NH2 by RHF, DFT, and MP2 computation and AIM analyses, confirmed by jet-cooled infrared data. $nameOfConference


    • Chin W, Mons M, Dognon J-P et al. (2005), The gas-phase dipeptide analogue acetyl-phenylalanyl-amide: a model for the study of side chain/backbone interactions in proteins. $nameOfConference


    • Law JMS, Fejer SN, Setiadi DH et al. (2005), Molecular orbital computations on lipids: an ab initio exploratory study on the conformations of glycerol and its fluorine congeners $nameOfConference


    • Sahai MA, Kehoe TAK, Koo JCP et al. (2005), First principle computational study on the full conformational space of L-proline diamides. $nameOfConference


    • Law JMS, Setiadi DH, Chass GA et al. (2005), Flexibility of "polyunsaturated fatty acid chains" and peptide backbones: A comparative ab initio study. $nameOfConference


    • Marai CNJ, Chass GA, Doust AB et al. (2004), An ab initio conformational. study on 2,3-dihydrobilin-1,19(21H,24H)-dione, a model compound for open-chain tetrapyrroles $nameOfConference


    • Chass GA, Marai CNJ, Setiadi DH et al. (2004), A Hartree-Fock, MP2 and DFT computational study of the structures and energies of '' b(2) ions derived from deprotonated peptides. A comparison of method and basis set used on relative product stabilities $nameOfConference


    • Sahai MA, Setiadi DH, Chass GA et al. (2003), A model study of the IgA hinge region: an exploratory study of selected backbone conformations of MeCO-L-Pro-L-Thr-NH-Me $nameOfConference


    • Sahai MA, Lovas S, Chass GA et al. (2003), A modular numbering system of selected oligopeptides for molecular computations: using pre-computed amino acid building blocks $nameOfConference


    • Sahai MA, Motiwala SS, Chass GA et al. (2003), An ab initio exploratory study of the full conformational space of MeCO-L-threonine-NH-Me $nameOfConference


    • Sahai MA, Sahai MR, Chass GA et al. (2003), An ab initio exploratory study on selected conformational features of MeCO-L-Ala-L-Ala-L-Ala-NH-Me as a XxxYyyZzz tripeptide motif within a protein structure $nameOfConference


    • Brijbassi SU, Sahai MA, Setiadi DH et al. (2003), An ab initio exploratory study on the conformational features of the dipeptide MeCO-Ala-Ala-NH-Me in its four different configurations: determination of the behaviour of D-enantiomer amino acids within a peptide chain $nameOfConference


    • Lau SK, Chass GA, Lovas S et al. (2003), An exploratory ab initio conformational analysis of selected fragments of nicotinamide adenine dinucleotide (NAD(+)). Part I: 5-deoxyribose nicotinamide N-glycoside $nameOfConference


    • Lau SK, Chass GA, Penke B et al. (2003), An exploratory ab initio conformational analysis of selected fragments of nicotinamide adenine dinucleotide (NAD(+)). Part II: adenosine $nameOfConference


    • Yeung GFC, Setiadi DH, Chass GA et al. (2003), An exploratory conformational analysis of D and L beta-6-deoxyglucose. An ab initio and DFT approach $nameOfConference


    • Keller JH, Chass GA, Csizmadia LG (2003), An isodesmic comparison of the C-1 modified reduced pteridine ring as a folic acid model $nameOfConference


    • Rassolian M, Chass GA, Setiadi DH et al. (2003), Asparagine - ab initio structural analyses $nameOfConference


    • Pecora TA, Owen MC, Marai CNJ et al. (2003), Bridging the gap between pure science and the general public: comparison of the informational exchange for these extremities in scientific awareness $nameOfConference


    • Setiadi DH, Chass GA, Koo JCP et al. (2003), Exploratory study on the full conformation space of alpha-tocopherol and its selected congeners $nameOfConference


    • Connor AA, Chasse GA, Setiadi DH et al. (2003), Hexachlorophene and triclosan - exploratory ab initio structural analyses $nameOfConference


    • Yeganegi M, Pylypenko D, Hon A et al. (2003), Intermolecular interactions of small biologically active molecules: acetone, methylamine and water; methyl phosphate, water and divalent ions; phenol and water; N-Ac-L-Gly-NH-Me and water $nameOfConference


    • Liao JCC, Chass GA, Setiadi DH et al. (2003), Molecular orbital analysis of the effect of D- and L-alanyl residues on the glycine chirality within the tripeptide N-Ac-Ala-Gly[beta]-Ala-NH-Me. An ab initio and DFT study $nameOfConference


    • Law JMS, Koo JCP, Setiadi DH et al. (2003), Molecular orbital computations on lipids: modular numbering $nameOfConference


    • Koo JCP, Lam JSW, Chass GA et al. (2003), Ramachandran backbone potential energy surfaces of aspartic acid and aspartate residues: implications on allosteric sites in receptor-ligand complexations $nameOfConference


    • Borics A, Chass GA, Csizmadia IG et al. (2003), The benefits of a pre-computed amino acid structure database in quantum chemical geometry optimizations of beta-turns of peptides $nameOfConference


    • Kehoe TAK, Peterson MR, Chass GA et al. (2003), The fitting and functional analysis of a double rotor potential energy surface for the R and S enantiomers of 1-chloro-3-fluoro-isobutane $nameOfConference


    • Sheraly AR, Chass GA, Csizmadia IG (2003), The multidimensional conformational analysis for the backbone across the disrotatory axis at selected side-chain conformers of N-Ac-homocysteine-NHMe - an ab initio exploratory study $nameOfConference


    • Chass GA (2003), Toward a computed structure database: Methodology for effective molecular orbital computations $nameOfConference


    • Setiadi DH, Chass GA, Torday LL et al. (2003), Vitamin E models. Shortened sidechain models of alpha, beta, gamma and delta tocopherol and tocotrienol - a density functional study $nameOfConference


    • Bagyi I, Balogh B, Czajlik A et al. (2003), Generation and analysis of the conformational potential energy surfaces of N-acetyl-N-methyl-L-alanine-N '-methylamide. An exploratory ab initio study $nameOfConference


    • Sull TJ, Chass GA, Varro A et al. (2003), A comparative conformational analysis of selected central nervous system stimulants $nameOfConference


    • Liao JCC, Chua JC, Chass GA et al. (2003), An assessment of the chiral environment created by adjacent D- and L-alanyl residues on a glycine unit within the tripeptide N-Ac-Ala-Gly-Ala-NHMe: an ab initio exploratory study $nameOfConference


    • Koo JCP, Lam JSW, Chass GA et al. (2003), Conformational dependence of the intrinsic acidity of the aspartic acid residue sidechain in N-acetyl-L-aspartic acid-N '-methylamide $nameOfConference


    • Setiadi DH, Chass GA, Torday LL et al. (2003), Vitamin E models. Can the anti-oxidant and pro-oxidant dichotomy of alpha-tocopherol be related to ionic ring closing and radical ring opening redox reactions? $nameOfConference


    • Koo JCP, Lam JSW, Salpietro SJ et al. (2002), How reliable could economic Hartree-Fock computations be in studying large, folded peptides? A comparative HF and DFT case study on N- and C-protected aspartic acid $nameOfConference


    • Law JMS, Chass GA, Torday LL et al. (2002), Molecular computations on lipids: a numbering system for phospholipids and triglyceride $nameOfConference


    • Sheraly AR, Chang RV, Chass GA (2002), Multidimensional conformational analysis of the sidechain conformers of the fully extended form backbone (beta(L)) of N-Ac-homocysteine-NHMe; an ab initio exploratory study $nameOfConference


    • Pisterzi LF, Almeida DRP, Chass GA et al. (2002), Density functional molecular computations on protonated serotonin in the gas phase and various solvent media $nameOfConference


    • Almeida DRP, Pisterzi LF, Chass GA et al. (2002), Density functional molecular study on the full conformational space of the S-4-(2-hydroxypropoxy)carbazol fragment of carvedilol (1-(9H-carbazol-4-yloxy)-3-[2-(2-methoxyphenoxy)ethylamino]-2-propanol) in vacuum and in different solvent media $nameOfConference


    • Chass GA, Marai CNJ, Harrison AG et al. (2002), Fragmentation reactions of a(2) ions derived from deprotonated dipeptides - A synergy between experiment and theory $nameOfConference


    • Setiadi DH, Chass GA, Torday LL et al. (2002), Vitamin E models. Conformational analysis and stereochemistry of tetralin, chroman, thiochroman and selenochroman $nameOfConference


    • Chass GA, Sahai MA, Law JMS et al. (2002), Toward a computed peptide structure database: The role of a universal atomic numbering system of amino acids in peptides and internal hierarchy of database $nameOfConference


    • Koo JCP, Chass GA, Perczel A et al. (2002), N-acetyl-L-aspartic acid-N'-methylamide with side-chain orientation capable of external hydrogen bonding $nameOfConference


    • Chass GA, Lovas S, Murphy RF et al. (2002), The role of enhanced aromatic pi-electron donating aptitude of the tyrosyl sidechain with respect to that of phenylalanyl in intramolecular interactions $nameOfConference


    • Setiadi DH, Chass GA, Torday LL et al. (2002), Vitamin E models - The effect of heteroatom substitution in 2-ethyl-2-methyl chroman and 2-ethyl-2-methyl-6-hydroxychroman $nameOfConference


    • Koo JCP, Chass GA, Perczel A et al. (2002), Exploration of the four-dimensional-conformational potential energy hypersurface of N-acetyl-L-aspartic acid N'-methylamide with its internally hydrogen bonded side-chain orientation $nameOfConference


    • Mehdizadeh A, Chass GA, Farkas O et al. (2002), Conformational effects of one glycine residue on the other glycine residues in the Ac-Gly-Gly-Gly-NHMe tripeptide motif: an ab initio exploratory study $nameOfConference


    • Lau KS, Mantas A, Chass GA et al. (2002), Ab initio and DFT conformational analysis of selected flavones: 5,7-dihydroxyflavone (chrysin) and 7,8-dihydroxyflavone $nameOfConference


    • McKague AB, Lough AJ, Chasse GA (2002), Chemical structure of the chlorination product of tribromoethylene $nameOfConference


    • Chasse GA, Mak ML, Deretey E et al. (2001), An ab initio computational study on selected lycopene isomers $nameOfConference


    • Chasse GA, Chasse KP, Kucsman A et al. (2001), Conformational potential energy surfaces of a Lycopene model $nameOfConference


    • Villagra SE, Santillan MB, Rodriguez AM et al. (2001), Dynamic chirality in selected diaryl methane containing drugs. An exploratory ab initio conformational study $nameOfConference


    • Bombasaro JA, Suvire FD, Chasse GA et al. (2001), Stereoelectronic effects and dynamic chirality in ethyl nitrite (Et-ONO) computed at the HF and DFT levels of theory $nameOfConference


    • Yeung JCY, Chasse GA, Frondozo EJ et al. (2001), Cationic intermediates in trans- to cis- isomerization reactions of allylic systems. An exploratory ab initio study $nameOfConference


    • Tarditi AM, Klipfel MW, Rodriguez AM et al. (2001), An ab initio exploratory study of side chain conformations for selected backbone conformations of N-acetyl-L-glutamine-N-methylamide $nameOfConference


    • Masman MF, Amaya MG, Rodriguez AM et al. (2001), An exploratory study of side-chain-backbone interaction in selected conformations of N-acetyl-L-glutamate-N-methylamide. An ab initio study $nameOfConference


    • Chasse GA, Rodriguez AM, Mak ML et al. (2001), Peptide and protein folding $nameOfConference


    • Berg MA, Chasse GA, Deretey E et al. (2000), Prospects in computational molecular medicine: a millennial mega-project on peptide folding $nameOfConference


Supervision

PhD supervision

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