Estrutura e algumas propriedades ópticas de difenilfosfinatos de terras-raras

Coordination compounds of trivalent lanthanides cations with diphenylphosphinate are originated from direct reaction between a lanthanide salt and diphenylphosphinic acid. These complexes have peculiar and intriguing features, as (i) quickly obtainment through wet process precipitation, (ii) appreciable thermal stability, similar to inorganic phosphates, (iii) polymeric structure, and consequently, (iv) low solubility in both polar and non-polar solvents. Nowadays, coordination polymers are classified as coordination networks or, in case of porous materials, as metal-organic frameworks (MOFs). By this study, we aim to determine some optical properties of rare-earth diphenylphosphinate (RE = La3+, Eu3+, Gd3+, Lu3+) and conduct an updated classification of these compounds, bringing more details of its structure and the possible proposal of new materials with applications in lighting, detection of ionizing radiation and magnetism. The complexes of trivalent rare-earth cation with diphenylphosphinate were prepared by direct mixture of diphenylphosphinic acid with rare-earth metal chloride, both in ethanolic solution. The solution of diphenylphosphinic acid was kept in a beaker under constant stirring with pH measurements of the solution and gadolinium chloride solution was then dripped slowly with the aid of a burette until its complete addition; the following metal:ligand molar ratios were tested: 1:1, 1:2, 1:3, 2:1 e 3:1. The compounds were characterized by spectroscopic and structural techniques. By Fourier Transform Infrared Spectroscopy (FT-IR), it was possible to check the total ionization of diphenylphosphinic acid in synthesized complexes, confirmed by the absence of the band type A, B, C related to ѵ(O-H) of the acid (2663 cm-1, 2168 cm-1, 1684 cm-1), as well as the disappearance of ѵ(P-OH)=961 cm-1. Furthermore, the occurrence of bands shifts of ѵ(POO-) [symmetrical and asymmetrical] of...

Determinantes da decisão de manter áreas protegidas em terras privadas: o caso das reservas legais do Estado de São Paulo

Frente ao debate atual que cerca a legislação florestal brasileira, o presente artigo explora a correlação entre variáveis econômicas e a proporção de áreas protegidas instituídas em terras privadas, as reservas legais, nos municípios do estado de São Paulo. Sua principal contribuição é apontar que argumentos utilizados para justificar o descumprimento e embasar alterações às regras de proteção ambiental vigentes, não se sustentam.

Festival de Cerdeña Musas e Terras: Grupo de Cerdeña

Vídeo grabado en Cerdeña

Festival de Cerdeña Musas e Terras: Grupo de Cerdeña

Vídeo grabado en Cerdeña

Festival de Cerdeña Musas e Terras: Bertsolaris

Vídeo grabado en Cerdeña

Festival de Cerdeña Musas e Terras: Argentina

Vídeo grabado en Cerdeña

Festival de Cerdeña Musas e Terras: Cerdeña

Vídeo grabado en Cerdeña. Repentina (Remu Orrú y Efis Cadde) con launedda (Andreas Pisu).

Festival de Cerdeña Musas e Terras: Cerdeña

Vídeo grabado en Cerdeña. Francesco Saba, guitarra

Festival de Cerdeña Musas e Terras: México

Vídeo grabado en Cerdeña

Festival de Cerdeña Musas e Terras: México

Vídeo grabado en Cerdeña

Festival de Cerdeña Musas e Terras

Vídeo grabado en Cerdeña

Wilhelm Knaack als Lasenius, Rollenbild, in: Hofmeister in tausend Aengsten : "Per jovem, per mare, per terras, juro et adjuro, testor et attestor - und nun frisch heraus!"

Signatur des Originals: S 36/F00951

Ocupaçâo, valorizaçâo e comércio de terras no norte do Rio Grande do Sul - séculos 19 e 20

This article focuses on some aspects of the agrarian history of Soledade, a town in the north of the state of Rio Grande do Sul, southern Brazil. Our aim is to understand how this area was in many ways affected by the Land Law of 1850, particularly in economic and social terms. Population growth, arrival of European immigrants and increasing privatization of the commons contributed for the increasing of land prices in the region during the second half of the 19 th century. Understanding this situation as a great opportunity to make money, some landowners, directly or through a colonization company, allotted and sold the land they had previously acquired through the Land Law of 1850

Ocupaçâo, valorizaçâo e comércio de terras no norte do Rio Grande do Sul - séculos 19 e 20

This article focuses on some aspects of the agrarian history of Soledade, a town in the north of the state of Rio Grande do Sul, southern Brazil. Our aim is to understand how this area was in many ways affected by the Land Law of 1850, particularly in economic and social terms. Population growth, arrival of European immigrants and increasing privatization of the commons contributed for the increasing of land prices in the region during the second half of the 19 th century. Understanding this situation as a great opportunity to make money, some landowners, directly or through a colonization company, allotted and sold the land they had previously acquired through the Land Law of 1850

Ocupaçâo, valorizaçâo e comércio de terras no norte do Rio Grande do Sul - séculos 19 e 20

This article focuses on some aspects of the agrarian history of Soledade, a town in the north of the state of Rio Grande do Sul, southern Brazil. Our aim is to understand how this area was in many ways affected by the Land Law of 1850, particularly in economic and social terms. Population growth, arrival of European immigrants and increasing privatization of the commons contributed for the increasing of land prices in the region during the second half of the 19 th century. Understanding this situation as a great opportunity to make money, some landowners, directly or through a colonization company, allotted and sold the land they had previously acquired through the Land Law of 1850