We construct a new grading on the Goldman Lie algebra of a closed oriented
surface by the winding number. This grading induces a grading on the HOMFLY-PT
skein algebra and related algebras. Our work supports the conjectures of B.
Cooper and P. SamuelsonComment: Changed acknowledgments and Definition 2.

Christophe Volkringer (1434343)

Ionut Mihalcea (1755682)

Natacha Henry (1434346)

Thierry Loiseau (1434349)

English

arXiv

Five coordination polymers based on uranyl–pyromellitates
have been hydrothermally synthesized, and their single-crystal XRD
structures have been analyzed. These different compounds, obtained
with different ammonia concentrations, exhibit either three-dimensional
(3D) or two-dimensional (2D) networks. Complex 1, (UO2)2(H2O)2(btec)·H2O, is a quite compact 3D structure containing isolated 7-fold
coordinated uranyl cations linked through the pyromellitate (noted
btec) and encapsulating free water species. Phase (NH4)­[(UO2)2(OH)­(H2O)­(btec)]·1.75H2O (2) offers a second 3D architecture built up from
dinuclear 7-fold coordinated uranyl units and mononuclear 8-fold coordinated
uranyl units linked through the organic ligands. This framework is
slightly more open because narrow one-dimensional (1D) channels trapping
water species are visible. Phase 3, (NH4)2[(UO2)6O2(OH)4(btec)1.5]·11H2O, consists of large 1D
lozenge-shaped channels (8.2 Å × 8.6 Å) delimited by
infinite ribbons (composed of 7-fold coordinated uranyl polyhedra
sharing edges) and pyromellitate ligands. Ammonium cations as well
as water molecules are trapped within the channels. The fourth compound,
(NH4)6[(UO2)3(btec)3]·12H2O (4), is lamellar with
sheets containing 8-fold coordinated uranyl centers linked through
the btec molecules, which have two nonbonded carboxylate functions
interacting with the intercalated ammonium cations. Compound 5 also consists of a layered structure, (UO2)3(OH)2(H2O)2(btec), with uncommon
trinuclear building blocks containing 7-fold (×2) and 8-fold
(×1) coordinated uranyl centers, linked through the btec molecules.
Fluorescence spectra of compounds 1, 3,
and 4 are also measured

FigShare

Uranyl–Pyromellitate
Coordination Polymers: Toward Three-Dimensional Open Frameworks with
Large Channel Systems

https://figshare.com/articles/Uranyl_Pyromellitate_Coordination_Polymers_Toward_Three_Dimensional_Open_Frameworks_with_Large_Channel_Systems/2566504

Gradation of Algebras of Curves by the Winding Number

Abstract

Similar works

Full text

Available Versions

FigShare

FigShare

FigShare

FigShare

FigShare

FigShare

FigShare

FigShare

FigShare