OPUS: Open Ulethbridge Scholarship
Open ULeth Scholarship (OPUS) is the University of Lethbridge's open access research repository. It contains a collection of materials related to research and teaching produced by the academic community.
Self-archiving your research in OPUS is one way to meet Open Access policies of granting agencies. It is important to retain your final, post-peer-reviewed drafts for submission to OPUS, as this is often the only version publishers will allow to be archived. Click here for information on the U of L Open Access Policy.
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Metal-ligand cooperation in bis(phosphinimine)-supported rhodium pincer complexes: from dehydrogenation to value-added products
(Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, 2025) Hsiang, Shou-Jen (Edward); University of Lethbridge. Faculty of Arts and Science; Hayes, Paul G.
Expansion of methodology towards the synthesis of pincer ligand (L = κ3-NNN’ = 2,5-[iPr2P=N(4-iPrC6H4)]2-N’(C4H2)-) supported rhodium tetrylene (κ2-L(CO)Rh(ER2); E = Si, Ge; κ2-L = κ2-NN’-Rh, κ1-N-E) and borylene (κ2-L(CO)Rh(BMes); Mes = mesityl) species is described, followed by investigations into the reactivity of these new complexes.
A metal-ligand cooperative approach was used to dehydrogenate group 14 starting materials of the form RR’EH2 (E = Si, Ge; R = aryl or alkyl; R’ = H, aryl or alkyl) and MesBH2 (Mes = mesityl), and the resulting complexes were characterized by a variety of instrumentational techniques (NMR, IR, EA). X-ray crystallography was used to unambiguously confirm the solid-state structure within these species, establishing the hemilability of the R3P=NAr “phosphinimine” nitrogen-donor of the pincer ligand as well as its base-stabilization capabilities.
Diverse reaction chemistry was demonstrated for these species, starting with dehydrocoupling reactions with pinacol, which provided proof that the activated main group functionalities could be used as {BMes}, {SiRR’}, and {GeRR’} synthons and transferred to organic substrates. Additionally, reaction of a base-stabilized borylene complex with a variety of alkynes and CO gas yielded highly functionalized boron-containing heterocycles ((PhC=CRBMesO)C=NPipp) that would be difficult to synthesize by alternative routes, showcasing the potential these systems have for applications. Finally, the H-substituted silylene complex, κ2-L(CO)Rh(Si(H)Mes), was demonstrated to react with tris(pentafluorophenyl)borane to yield an elusive silylyne complex, the first of its kind with rhodium.
Altogether, a cohesive body of work encompassing the development of new methodologies, diverse reaction chemistry, and the presentation of future areas for pursuit are described herein.
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Exploring the impact of surface lapse rate change scenarios on mountain permafrost distribution in four dissimilar valleys in Yukon, Canada
(Canadian Science Publishing, 2024) Garibaldi, Madeleine C.; Bonnaventure, Philip P.; Noad, NIck C.; Kochtitzky, Will
A scenario-based approach was used to test air and ground response to warming with and without changes to inverted
surface lapse rates in four Yukon valleys. Generally, climate warming coupled with weakening of temperature inversions
resulted in the greatest increase in air temperature at low elevations. However, ground temperatures at high elevations showed
the greatest response to warming and variability between scenarios due to increased connectivity between air and ground.
Low elevations showed less of a response to warming and permafrost was largely preserved in these locations. Local models
also predicted higher permafrost occurrence compared to a regional permafrost probability model, due to the inclusion of
differential surface and thermal offsets. Results show that the spatial warming patterns in these mountains may not follow
those predicted in other mountain environments following elevation-dependent warming (EDW). As a result, the concept of
EDW should be expanded to become more inclusive of a wider range of possible spatial warming distributions. The purpose of
this paper is not to provide exact estimations of warming, but rather to provide hypothetical spatial warming patterns, based
on logical predictions of changes to temperature inversion strength, which may not directly follow the distribution projected through EDW.
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Pandemic babies: infant communication development in a global disaster
(Lethbridge, Alta. : University of Lethbridge, Faculty of Health Sciences, 2025) Swisterski, Mahala E. C.; University of Lethbridge. Faculty of Health Sciences; Currie, Cheryl L.; Gibb, Robbin L.
Infant communication development is influenced by the home environment, particularly in low-income families where stressors and resource limitations are common. This thesis investigates the impact of two key factors (pandemic unemployment benefits and reading frequency) on infant communication development during the COVID-19 pandemic. Data were drawn from the Baby’s First Years Study, a longitudinal study of approximately 600 mother-infant dyads living in low-income households across several U.S. cities.
Chapter two examined whether pandemic unemployment benefits were associated with communication development. The outcome variable was measured using the Ages and Stages Questionnaire at age one and the McArthur-Bates Communication Development Index at age two. Pandemic unemployment benefits were weakly but significantly associated with higher infant communication scores over a one-year period, even after adjusting for confounders. Infants in households receiving benefits scored, on average, 0.15 standardized units higher than those in non-recipient households (95% CI: 0.02 – 0.29).
Chapter three investigated whether maternal reading frequency was associated with changes in infant communication scores over a one-year period. Reading frequency was measured categorically, and results were stratified based on whether the age one data were collected before or during the pandemic. Infants whose mothers read to them daily scored 0.33 units higher in communication z-score (95% CI: 0.15 – 0.52). Stratified analyses showed significant associations prior to the pandemic but not during, suggesting that pandemic stress may have attenuated this association.
These findings highlight the potential of economic and educational supports to promote communication development in low-income families. This research underscores the importance of policies and interventions that buffer against crises and support equitable developmental outcomes for infants in vulnerable populations.
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SEE-IQ chart handout
(2025) Craig, Romany
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Quality control impacts on total precipitation gauge records for montane valley and ridge sites in SW Alberta, Canada
(MDPI, 2022) Barnes, Celeste; Hopkinson, Christopher
This paper presents adjustment routines for Geonor totalizing precipitation gauge data collected from the headwaters of the Oldman River, within the southwestern Alberta Canadian Rockies. The gauges are situated at mountain valley and alpine ridge locations with varying degrees of canopy cover. These data are prone to sensor noise and environment-induced measurement errors requiring an ordered set of quality control (QC) corrections using nearby weather station data. Sensor noise at valley sites with single-vibrating wire gauges accounted for the removal of 5% to 8% (49–76 mm) of annual precipitation. This was compensated for by an increase of 6% to 8% (50–76 mm) from under-catch. A three-wire ridge gauge did not experience significant sensor noise; however, the under-catch of snow resulted in 42% to 52% (784–1342 mm) increased precipitation. When all QC corrections were applied, the annual cumulative precipitation at the ridge demonstrated increases of 39% to 49% (731–1269 mm), while the valley gauge adjustments were −4% to 1% (−39 mm to 13 mm). Public sector totalizing precipitation gauge records often undergo minimal QC. Care must be exercised to check the corrections applied to such records when used to estimate watershed water balance or precipitation orographic enhancement. Systematic errors at open high-elevation sites may exceed nearby valley or forest sites.