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Quantitative information about halogenated hydrocarbons is important for understanding their impact on atmospheric ozone chemistry and climate change, their regulation, and the devising of improved substitutes. The Montreal Protocol aimed to regulate the utilization and manufacturing of hydrochlorofluorocarbon compounds (HCFCs), contributing to ozone layer depletion. The 2016 Kigali Amendment to the Montreal Protocol agreement, Annex C listed 274 HCFCs. Only 16 of them have been measured experimentally. The rest were set to zero by default. These reported global warming potentials (GWPs) play a crucial role in formulating policies for gradually reducing the usage and production of HCFCs to prevent atmospheric impact. Here we are studying 1-chloro-1-fluoro-ethane (CH3CHFCl) as a test of past theory. There are no prior experimental measurements of the reactivity of CH3CHFCl with hydroxyl (OH) radicals, which primarily determines its atmospheric lifetime, nor of its infrared (IR) spectrum. Saturated hydrofluorocarbons (HFCs) are non-ozone depleting substitutes for chlorofluorocarbons deprecated under the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, but they exhibit high global warming potentials (GWPs) and the Kigali Amendment adopted in 2016 outlines their phase down. Unsaturated HFCs offer more reactive alternatives, whose likely short atmospheric lifetimes would imply small GWPs. Because their GWPs are smaller than those for saturated HFCs by several orders of magnitude, and especially for fully fluorinated examples, several halogenated olefins are under consideration for practical application. We studied HCF2CF2CF=CF2, cis-HCF=HCF, trans HCF=HCF, CF2=CH2 unsaturated HFCs.

Silver monolayer-protected clusters (MPCs) are fundamentally different than their bulk counterparts due to their discrete size distributions and precise molecular formulas. Many studies have been reported on the synthesis of silver MPCs in recent years, however study of their formation mechanism is still lacking. Despite existing models, the formation mechanism of metal monolayer-protected clusters (MPCs) does not have a satisfactory explanation. A new model for silver-glutathione (Ag-SG) MPC formation was recently proposed, successfully explaining that metal MPCs grow sequentially, increasing in size systematically.1 To understand the sequential growth model further, the silver-p-MBA system was chosen since it is more quantitative with two known stable species, i.e. [Ag44(p-MBA)30]4- and [Ag17(p-MBA)12]3-, each with measured crystal structures.2 It was hypothesized herein that [Ag44(p-MBA)30]4- forms sequentially from [Ag17(p-MBA)12]3-. By spectroscopically tracking the synthesis of [Ag44(p-MBA)30]4- in situ and with controlled kinetics, then analyzing the species formed during its synthesis by spectral decomposition, the concentrations of reaction products can be tracked over the course of the reaction in order to better understand the formation mechanism. Our studies and analyses concluded that the synthesis of [Ag44(p-MBA)30]4- indeed follows the sequential growth model.Further we have studied the syntheses under aerobic and anaerobic atmospheres. Some studies have reported that oxygen is involved via an etching process to produce MPCs.3, 4 So, here we have investigated the impact of oxygen on the synthesis of Ag-p-MBA MPCs. The syntheses of Ag-p-MBA MPCs were studied under Ar and air atmospheres using in situ optical absorption spectroscopy which enabled the tracking of species over the course of reactions. Based on our observations, it was concluded that the synthesis of Ag-p-MBA MPCs follows a different pathway under air and Ar atmospheres. It was found that the intermediates could reach much higher concentrations in the reaction mixtures under anaerobic conditions than for aerobic conditions, suggesting that oxygen has an effect on the stability of intermediates and provides an alternative pathway to forming Ag44. A new growth model was therefore formulated that consists of a direct sequential growth pathway for anaerobic conditions and an indirect pathway for aerobic conditions, both of which ultimately produce Ag44. The direct pathway grows from monomers to Ag17 to intermediates to Ag44, the last step being slow. The indirect pathway consists of the same initial sequential growth from monomers to Ag17 to intermediates but is followed by an oxygen-mediated step, which might produce a smaller intermediate via oxidative decomposition, before growth continues to Ag44, the last two steps being fast. Both pathways are ultimately consistent with the principles of sequential growth, since the overall tendency in each is growth, although the existence of an oxygen-mediated pathway shows that Ag MPC growth may be more complex than the initial proposed form of the sequential growth model.