O consumo colaborativo como alternativa ao consumo de massa: a percepção do consumidor em bairros de Florianópolis e a relação do consumo colaborativo com valores pessoais.

TCC (graduação) - Universidade Federal de Santa Catarina. Centro Sócio-Econômico. Economia.O tipo de consumo que a sociedade habituou-se ao longo das últimas décadas tem ocasionado problemas que impactam diretamente o cotidiano das pessoas. Alavancado por motivações individuais e questões ambientais, sociais e econômicas, o consumo colaborativo é um fenômeno recente que vem alterando o funcionamento da economia global ao proporcionar aos consumidores uma nova forma de acomodar seus desejos e necessidades de maneira conveniente e sustentável. Associado a isso, as redes de informação energizadas pela Internet têm modificado significativamente o modo e a velocidade com que os agentes econômicos se relacionam. Nesse sentido, o objetivo maior deste trabalho de conclusão do Curso de Ciências Econômicas é identificar a percepção dos consumidores da Grande Florianópolis acerca do consumo colaborativo como alternativa ao modelo de consumo tradicional. O estudo é dividido em três partes principais. Inicialmente recorre-se a pesquisa bibliográfica para contextualizar e conceituar os termos economia compartilhada e consumo colaborativo, suas formas e princípios. Visando conhecer os efeitos desse movimento no Brasil e especificamente em Florianópolis, na sequencia realiza-se pesquisa através de questionários para identificar a propensão do consumidor a participar de práticas de consumo colaborativo em quatro regiões: Lagoa da Conceição, Centro, Trindade e Continente. Considerando que os valores pessoais interferem no comportamento do consumidor, busca-se avaliar qualitativamente de que forma tais valores se relacionam com a disposição dos mesmos a participar do consumo colaborativo. Através do questionário aplicado, ainda que com amostra limitada, observa-se que os consumidores apresentam de modo geral nível satisfatório de propensão a participar do consumo colaborativo, sendo a Lagoa da Conceição a localidade com maior adesão, seguida por Continente, Trindade e Centro. Além disso, a mensuração dos valores pessoais permite observar que os consumidores mais abertos a mudança, menos conservadores e menos apegados materialmente apresentam maior propensão a participar do consumo colaborativo, como é o caso da Lagoa da Conceição. As considerações finais discutem os principais achados e limitações do estudo

Conformationally Preorganized High-Affinity Ligands for Copper Biology with Hinged and Rigid Thiophene Backbones

Copper-selective ligands are essential tools for probing the affinity of cuproproteins or manipulating the cellular copper availability. They also harbor significant potential as antiangiogenic agents in cancer therapy or as therapeutics to combat copper toxicity in Wilson’s disease. To achieve the high Cu(I) affinities required for competing effectively with cellular cuproproteins, we recently devised a ligand design based on phosphine-sulfide-stabilized phosphine (PSP) donor motifs. Building on this design strategy, we integrated two PSP donors within preorganized ligand architectures composed of either a hinged bithiophene backbone (bithipPS) or a single rigid thiophene bridge (thipPS). Extensive characterization based on X-ray crystal structures, solution NMR data, spectrophotometric titrations, and electrochemical studies established that bithipPS adapts well to the coordination preferences of Cu(I) to form a discrete air-stable mononuclear Cu(I) complex with a dissociation constant of 4 zM. In contrast, the wider bite angle of thipPS introduces some strain upon Cu(I) coordination to yield an almost 10-fold lower affinity with a Kd of 35 zM. As revealed by ICP-MS and two-photon excitation microscopy studies with the Cu(I)-selective fluorescent probe crisp-17, both ligands are effective at removing cellular copper from live mouse fibroblasts with rapid kinetics. Altogether, the stability and redox properties of PSP-ligand–Cu(I) complexes can be effectively tuned by judicious balancing of their geometrical preorganization and conformational flexibility

Hydrogen Peroxide Complex of Zinc

Metal­(H₂O₂) complexes have been implicated in kinetic and computational studies but have never been observed. Accordingly, H₂O₂ has been described as a very weak ligand. We report the first metal­(H₂O₂) adduct, which is made possible by incorporating intramolecular hydrogen-bonding interactions with bound H₂O₂. This Zn^II(H₂O₂) complex decays in solution by a second-order process that is slow enough to enable characterization of this species by X-ray crystallography. This report speaks to the intermediacy of metal­(H₂O₂) adducts in chemistry and biology and opens the door to exploration of these species in oxidation catalysis

Rhodium(II)-Catalyzed Asymmetric Cyclopropanation and Desymmetrization of [2.2]Paracyclophanes

Chiral [2.2]paracyclophane derivatives are of considerable interest because of their potential in asymmetric catalysis and the development of chiral materials. This study describes the scope of rhodium-catalyzed reactions of aryldiazoacetates with [2.2]paracyclophanes. The reaction with the parent [2.2]paracyclophane resulted in cyclopropanation at two positions, the ratio of which is catalyst-controlled. Because of the strain in the system, one of the cyclopropanes exists primarily as the norcaradiene structure, whereas the other preferentially exists as the cycloheptatriene conformer. In contrast, the reaction with [3.3]paracyclophane results in benzylic C–H functionalization. The reactions with substituted [2.2]paracyclophanes using chiral catalysts can result in either kinetic resolution or desymmetrization. The Rh2(S-p-PhTPCP)]4-catalyzed reaction of monosubstituted paracyclophanes results in kinetic resolution with a selectivity (s) factor of up to 20, whereas reactions on C2v-symmetric disubstituted [2.2]paracyclophanes with Rh2(S-TPPTTL)4 [TPPTTL = 2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate] results in effective desymmetrization to form cycloheptatriene-incorporated paracyclophanes in 78–98% ee

Rhodium(II)-Catalyzed Asymmetric Cyclopropanation and Desymmetrization of [2.2]Paracyclophanes

Chiral [2.2]paracyclophane derivatives are of considerable interest because of their potential in asymmetric catalysis and the development of chiral materials. This study describes the scope of rhodium-catalyzed reactions of aryldiazoacetates with [2.2]paracyclophanes. The reaction with the parent [2.2]paracyclophane resulted in cyclopropanation at two positions, the ratio of which is catalyst-controlled. Because of the strain in the system, one of the cyclopropanes exists primarily as the norcaradiene structure, whereas the other preferentially exists as the cycloheptatriene conformer. In contrast, the reaction with [3.3]paracyclophane results in benzylic C–H functionalization. The reactions with substituted [2.2]paracyclophanes using chiral catalysts can result in either kinetic resolution or desymmetrization. The Rh2(S-p-PhTPCP)]4-catalyzed reaction of monosubstituted paracyclophanes results in kinetic resolution with a selectivity (s) factor of up to 20, whereas reactions on C2v-symmetric disubstituted [2.2]paracyclophanes with Rh2(S-TPPTTL)4 [TPPTTL = 2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate] results in effective desymmetrization to form cycloheptatriene-incorporated paracyclophanes in 78–98% ee

Rhodium(II)-Catalyzed Asymmetric Cyclopropanation and Desymmetrization of [2.2]Paracyclophanes

Chiral [2.2]paracyclophane derivatives are of considerable interest because of their potential in asymmetric catalysis and the development of chiral materials. This study describes the scope of rhodium-catalyzed reactions of aryldiazoacetates with [2.2]paracyclophanes. The reaction with the parent [2.2]paracyclophane resulted in cyclopropanation at two positions, the ratio of which is catalyst-controlled. Because of the strain in the system, one of the cyclopropanes exists primarily as the norcaradiene structure, whereas the other preferentially exists as the cycloheptatriene conformer. In contrast, the reaction with [3.3]paracyclophane results in benzylic C–H functionalization. The reactions with substituted [2.2]paracyclophanes using chiral catalysts can result in either kinetic resolution or desymmetrization. The Rh2(S-p-PhTPCP)]4-catalyzed reaction of monosubstituted paracyclophanes results in kinetic resolution with a selectivity (s) factor of up to 20, whereas reactions on C2v-symmetric disubstituted [2.2]paracyclophanes with Rh2(S-TPPTTL)4 [TPPTTL = 2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate] results in effective desymmetrization to form cycloheptatriene-incorporated paracyclophanes in 78–98% ee

Rhodium(II)-Catalyzed Asymmetric Cyclopropanation and Desymmetrization of [2.2]Paracyclophanes

Chiral [2.2]paracyclophane derivatives are of considerable interest because of their potential in asymmetric catalysis and the development of chiral materials. This study describes the scope of rhodium-catalyzed reactions of aryldiazoacetates with [2.2]paracyclophanes. The reaction with the parent [2.2]paracyclophane resulted in cyclopropanation at two positions, the ratio of which is catalyst-controlled. Because of the strain in the system, one of the cyclopropanes exists primarily as the norcaradiene structure, whereas the other preferentially exists as the cycloheptatriene conformer. In contrast, the reaction with [3.3]paracyclophane results in benzylic C–H functionalization. The reactions with substituted [2.2]paracyclophanes using chiral catalysts can result in either kinetic resolution or desymmetrization. The Rh2(S-p-PhTPCP)]4-catalyzed reaction of monosubstituted paracyclophanes results in kinetic resolution with a selectivity (s) factor of up to 20, whereas reactions on C2v-symmetric disubstituted [2.2]paracyclophanes with Rh2(S-TPPTTL)4 [TPPTTL = 2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate] results in effective desymmetrization to form cycloheptatriene-incorporated paracyclophanes in 78–98% ee

Hydrogen Peroxide Complex of Zinc

Metal­(H₂O₂) complexes have been implicated in kinetic and computational studies but have never been observed. Accordingly, H₂O₂ has been described as a very weak ligand. We report the first metal­(H₂O₂) adduct, which is made possible by incorporating intramolecular hydrogen-bonding interactions with bound H₂O₂. This Zn^II(H₂O₂) complex decays in solution by a second-order process that is slow enough to enable characterization of this species by X-ray crystallography. This report speaks to the intermediacy of metal­(H₂O₂) adducts in chemistry and biology and opens the door to exploration of these species in oxidation catalysis

Convergent and Efficient Total Synthesis of (+)-Heilonine Enabled by C–H Functionalizations

We report a convergent and efficient total synthesis of the C-nor D-homo steroidal alkaloid (+)-heilonine with a hexacyclic ring system, nine stereocenters, and a trans-hydrindane moiety. Our synthesis features four selective C–H functionalizations to form key C–C bonds and stereocenters, a Stille carbonylative cross-coupling to connect the AB ring system with the DEF ring system, and a Nazarov cyclization to construct the five-membered C ring. These enabling transformations significantly reduced functional group manipulations and delivered (+)-heilonine in 11 or 13 longest linear sequence (LLS) steps

Rhodium(II)-Catalyzed Asymmetric Cyclopropanation and Desymmetrization of [2.2]Paracyclophanes

Chiral [2.2]paracyclophane derivatives are of considerable interest because of their potential in asymmetric catalysis and the development of chiral materials. This study describes the scope of rhodium-catalyzed reactions of aryldiazoacetates with [2.2]paracyclophanes. The reaction with the parent [2.2]paracyclophane resulted in cyclopropanation at two positions, the ratio of which is catalyst-controlled. Because of the strain in the system, one of the cyclopropanes exists primarily as the norcaradiene structure, whereas the other preferentially exists as the cycloheptatriene conformer. In contrast, the reaction with [3.3]paracyclophane results in benzylic C–H functionalization. The reactions with substituted [2.2]paracyclophanes using chiral catalysts can result in either kinetic resolution or desymmetrization. The Rh2(S-p-PhTPCP)]4-catalyzed reaction of monosubstituted paracyclophanes results in kinetic resolution with a selectivity (s) factor of up to 20, whereas reactions on C2v-symmetric disubstituted [2.2]paracyclophanes with Rh2(S-TPPTTL)4 [TPPTTL = 2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate] results in effective desymmetrization to form cycloheptatriene-incorporated paracyclophanes in 78–98% ee