The ruthenium dinuclear complexes with end-caping of pyridinedicarboxylate complexes of terpyridine (2,2':6',2'-terpyridine) and (tBu)3-terpyridine (4,4¡¦,4¡¦¡¦-tri-tert-butyl-2,2¡¦:6¡¦,2¡¦¡¦-terpyridine) bridging with carbon-rich alkynyl group are reported. These novel complexes are characterized by NMR, MALDI-MS, FT-IR, UV, and electrochemistry. In comparison with the system of tpy-Ru-tpy-(¡Ý)n-tpy-Ru-tpy, we found some interesting characteristics in the studies of electronic spectra and electrochemical measurements. Furthermore, one reversible and one irreversible electrochemical redox waves in positive wave were observed (E1/2 at 0.59 and 1.15 V (irrev.) for the complex with ethynyl spacer and E1/2 at 0.62 and 1.10 V (irrev.) for the complex with butynyl spacer), indicating a strong electronic interaction between two Ru metal centers. However, in the tpy-Ru-tpy-(¡Ý)n-tpy-Ru-tpy system, only one electrochemical redox wave at ~1.3 V was found. From the electronic and electrochemical analysis , the electronic interaction between two metal centers decreases as the number of alkynyl group increases.

Commonly viewed as the shortest cross sections of armchair carbon nanotubes (CNTs), cycloparaphenylenes (CPPs) represent a unique class of conjugated macrocycles with rigid backbones. In addition to their utility in seeding the growth of uniform CNTs, these strained nanohoops and their derivatives have unique optoelectronic and supramolecular properties for potential applications in materials science. Herein we present our efforts in designing novel nanohoop architectures and new types of strained macrocycles that serve as building blocks for functional materials. Chapter I briefly reviewed the under-represented reactivity studies of strained aromatic macrocycles. Chapter II describes our early efforts in probing the structure-property relationships of oligophenylene macrocycles focusing on the understanding of the influence of structural bending and cyclic conjugation on the optoelectronic properties. Chapter III reports the reactivity study of 1,4-anthracene-incorporated [12]CPP, a model substrate to examine the feasibility of using anthracene as the functional handle to crosslink nanohoops. Chapter IV presents the synthesis of a molecular propeller with three nanohoop blades and examines its unique hexagonal layered packing structure. In Chapter V, we disclose the synthesis of strained stilbene macrocycles suitable for ring-opening metathesis polymerization (ROMP) as well as the initial ROMP studies of this monomeric system. This dissertation contains previously published and unpublished coauthored materials.

Northern peatlands are a globally important soil carbon (C) store, and aquatic systems draining peatland catchments receive a high loading of dissolved and particulate forms of C from the surrounding terrestrial environment. Once incorporated into the aquatic environment, internal processes occur to modify the C pool. Of these, photo-processing preferentially targets terrestrially derived C and therefore might have a significant effect on the C budget of peatland draining aquatic systems. The overarching aim of this study was to investigate photochemical processing of C in Scottish peatland draining aquatic systems in order to determine the importance of this pathway in aquatic biogeochemical cycles. For initial laboratory experiments, water samples from a peatland headwater stream (Auchencorth Moss, SE Scotland) were collected. Laboratory based irradiation experiments were conducted at a range of temperatures, and different filtration treatments, including unfiltered samples, were employed to understand the fraction of C most susceptible to photo-processing. UV irradiation and temperature had a significant effect on DOC and gas headspace concentrations, with Q10 values of ~1.42 and ~1.65 derived for CO2 and CO photoproduction in unfiltered samples, respectively. However, filtration treatment did not induce significant changes in gaseous C production between light and dark samples, indicating that the experimental conditions favoured breakdown of DOC rather than POC to CO2 and CO. In all light treatments a small but significant increase in CH4 concentration was detected. These data were compared to results from experiments conducted in ambient light and temperature conditions. DOC normalised CO2 photoproduction was an order of magnitude lower than in laboratory conditions, although relative abundances of C species within overall budgets were similar and these experiments demonstrated that ambient exposure is sufficient to generate photo-processing of aquatic peatland C. Overall these data show that peatland C, particularly the < 0.2 μm fraction, is highly photoreactive and that this process is temperature sensitive. Further laboratory irradiation experiments were conducted on filtered water samples collected over a 13-month period from two contrasting aquatic systems. The first was the headwater stream draining Auchencorth Moss peatland with high DOC concentrations. The second was a low DOC reservoir (Loch Katrine, C Scotland) situated in a catchment with a high percentage peat cover. Samples were collected monthly from May 2014 to May 2015 and from the stream system during two rainfall events. Significant variation was seen in the photochemical reactivity of DOC between the two systems, with total irradiation induced change typically two orders of magnitude greater and DOC normalised CO2 production a factor of two higher in the headwater stream samples. This is attributed to longer water residence times in the reservoir rendering a higher proportion of the DOC recalcitrant to photo-processing. Overall the magnitude of photo-induced C losses was significantly positively correlated with DOC concentration in the headwater stream, which varied seasonally with highest concentrations detected in late autumn and winter. Rainfall events were identified as important in replenishing the stream system with photoreactive material, with lignin phenol data indicating mobilisation of fresh DOC from woody vegetation in the upper catchment during a winter rainfall event. Whilst these data clearly demonstrate that peatland catchments generate significant volumes of photoreactive DOC, the degree to which it is processed in the aquatic environment is unclear. Field investigations were undertaken to address this uncertainty. In-situ experiments with unfiltered water samples in light and dark conditions were conducted in two contrasting open water peatland pool systems. At the high DOC site (Red Moss of Balerno, SE Scotland), DOC concentrations in surface light exposed samples decreased by 18% compared to dark controls over 9 days and light treatments were enriched in CO2 and CH4. Photochemical processing was evident in δ13C-DOC and δ13C-DIC signatures of light exposed samples, which were enriched and depleted, respectively, relative to dark controls (+0.23 ‰ and -0.38 ‰) after 9 days of surface exposure. At the low DOC site (Cross Lochs, Forsinard, N Scotland) net production of DOC occurred in both light and dark samples over the experiment duration, in part due to POC breakdown. δ13C-DIC signatures indicated photolysis had occurred in light exposed samples (-1.98 ‰), whilst δ13C-DOC data suggest an absence of photo-processing, as the signatures in both treatments were similar. Accounting for light attenuation through the water column, 46 ± 4.9 and 8.7 ± 0.5 g C-CO2 eq m−2 yr−1 was processed by photochemical and microbial activity in peatland pools within the catchments at the high and low DOC sites, respectively. At both sites, light driven processing was responsible for a considerable percentage (34 and 51%) of gaseous C production when compared to equivalent estimates of microbial C processing and thus should be considered a key driver of peatland pool biogeochemical cycles. It is clear from this study that temperature, seasonal cycles, rainfall events and water residence time provide strong controls on the photoreactivity of aquatic C in Scottish peatland systems. The photo-processing pathway has the potential to alter the C balance of peatland catchments with a high percentage coverage of aquatic systems. Under climate change scenarios where light, temperature and rainfall conditions are expected to change, this process may become increasingly important in aquatic C cycling, particularly if the upward trend in DOC concentrations in northern aquatic systems continues.

Intrashelf basins occurring on epeiric carbonate platforms are commonly associated with the presence of excellent carbonate source rocks, and because they often border potential carbonate reservoirs updip, they may form the core of rich petroleum systems. This is a common phenomenon of many Mesozoic hydrocarbon plays in the Middle East. Despite this fact, studies investigating intrashelf-basinal, fine-grained carbonates are rare, because it is assumed that little lithofacies variability is present in these successions as a consequence of their relatively homogeneous appearance where they are sampled in core or visited in exposures. Those that have been performed mostly lack process-detail analyses, and interpret the organic-carbon enrichment in these sediments to be simply a function of either occurrence of localised bottom-water anoxia or high primary organic production under low-energy conditions, dominated by suspension-settling events.