Evaluation of a New Interactive First-Year Undergraduate Symmetry Coursework Activity

Knowledge of symmetry operations and point groups in first-year undergraduate chemistry is crucial for the understanding of more advanced topics in later years, such as spectroscopy, group theory and crystallography. However, symmetry is an abstract topic and many first-years find it problematic, both in terms of understanding and engagement with the material. In particular, the visualisation of molecules in 3D and applying symmetry operations presents a key challenge for many students. We designed a new method of symmetry assessment for first-year chemistry undergraduates, which encouraged them to look at the symmetry of everyday objects (such as buildings, street furniture or household items) in addition to standard molecules. The participants uploaded photos of interesting objects they found to Moodle (UCL’s virtual learning environment) and, within small groups, they discussed the symmetry elements within them and came to a consensus on the objects’ point groups. With many everyday objects, there was room for debate (expected to encourage deeper learning), which led to a variety of point groups being proposed for the same object. Using pre- and post-coursework questionnaires and diagnostic quizzes, we evaluated this e-learning approach and compared the results with a control group (who did the standard coursework). The effectiveness of this activity and the next steps will be discussed

Welcome! Using Moodle to Ease New Chemistry Students' Transition to Higher Education

The transition from high-school to university can be particularly daunting for students, especially if they are coming from abroad. We designed a Moodle page for incoming students with a view to helping alleviate their anxiety and reducing their cognitive load during induction week by introducing enrolment and departmental information early. The page was built by a first-year undergraduate, who used her own and her cohort’s experiences to design the content. Common questions were addressed, practice problems were provided and pre-reading and information about the department (including a virtual department tour and airline-style lab safety videos) was given. Students were automatically enrolled on the page as soon as they obtained their IT credentials in early September. They were asked to complete a quiz and questionnaires before induction week. The questionnaire gave insight into which features the students found the most useful, how confident they felt and what their expectations of university life were. The outcomes of the survey will be discussed and recommendations for similar pages will be made

Rethinking Assessment of First-Year Undergraduate Symmetry with E-Learning Techniques

The knowledge of symmetry operations and point groups in first-year undergraduate chemistry is crucial for the understanding of more advanced topics in later years, such as spectroscopy, group theory and crystallography. However, symmetry is a topic with which many first-years struggle, both in terms of understanding and engagement with the material. In particular, the visualisation of molecules in 3D and applying symmetry operations presents a key challenge for many students. We have designed a new method of symmetry assessment for first-year chemistry undergraduates, which encourages them to look at the symmetry of everyday objects, such as buildings, street furniture or household items. The participants upload photos of interesting objects they find to Moodle (UCL’s virtual learning environment) and, within groups, discuss the symmetry elements within them, leading to assignment of a point group. With many everyday objects, there is room for debate, for example, when considering the symmetry of a street sign, should the whole sign be included in the assessment or just the face. This debate and peer dialogue fosters deeper learning and can then be applied to molecules and molecular orbitals. The effectiveness of this approach will be assessed in the coming academic year and compared to a control group, and a group completing the coursework in its current form of a Moodle quiz

Precursor Synthesis and Chemical Vapour Deposition of Transition Metal Nitrides and Carbonitrides

This thesis is concerned with the chemical vapour deposition (CVD) of tungsten and zirconium nitride and carbonitride thin films. [W(μ-NtBu)(NtBu)Cl2(H2NtBu)]2, [W(NtBu)2Cl2(TMEDA)] (TMEDA = N,N,N’,N’-tetramethylethylenediamine) and [W(NtBu)2Cl2(py)2] (py = pyridine) have been investigated as potential precursors. Additionally, two novel precursors, [W(NtBu)2Cl{N(SiMe3)2}] and [W(NtBu)2(η5-Cp’)(η1-Cp’)] (Cp’ = methylcyclopentadienyl), have been synthesised via metathesis reactions of [W(NtBu)2Cl2(py)2] with the appropriate lithium or sodium amide salt. The attempted synthesis of [W(NtBu)2Cl{N(H)NMe2}] by lithium salt metathesis was unsuccessful due to polymerisation. Cyclopentadienyl-based precursors to zirconium carbonitride have been investigated, including [ZrCp2(NMe2)2], [ZrCp’2(NMe2)2] and four novel compounds: [ZrCp2(η2-MeNCH2CH2NMe)], [ZrCp’2(NEt2)2], [ZrCp’{(iPrN)2CNMe2}2Cl] and [ZrCp’2{(iPrN)2CNMe2}Cl] (Cp = 5-cyclopentadienyl, Cp’ = 5- methylcyclopentadienyl). The compounds were synthesised via sodium or lithium metathesis reactions. All compounds synthesised were characterised by NMR, mass spectrometry, elemental analysis and IR, and their decomposition was investigated by thermogravimetric analysis (TGA). The molecular structures of [ZrCp’{(iPrN)2CNMe2}2Cl] and [ZrCp’2{(iPrN)2CNMe2}Cl] were determined by single crystal X-ray diffraction. Thin films of tungsten carbonitride, zirconium carbide and zirconium carbonitride were deposited by low pressure CVD (LPCVD) at 550-600 °C and 0.1 Torr using the aforementioned precursors. In addition, aerosol-assisted CVD (AACVD) of [W(μ-NtBu)(NtBu)Cl2(H2NtBu)]2 in toluene was investigated as a comparison. All films deposited via CVD were characterised using wavelength dispersive X-ray spectroscopy (WDX), glancing-angle XRD, UV/Vis spectroscopy (for reflectance and transmission measurements) and their morphology and thickness were investigated using SEM imaging. Plasma-enhanced atomic layer deposition (PEALD) using [ZrCp2(NMe2)2] and [ZrCp2(η2-MeNCH2CH2NMe)] was studied with the view to depositing stoichiometric ZrN. It showed these precursors to be insufficiently volatile for the ALD system as the growth rates were low. The ALD progress was analysed using in situ ellipsometry and mass spectrometry