Funktionale poröse Koordinationspolymere

Abstract

Die Chemie der Koordinationspolymere hat sich in den vergangenen Jahren rasant entwickelt. Strukturen aus einer Vielzahl molekularer Bausteine mit unterschiedlichen Wechselwirkungen sind mittlerweile zugänglich. Die nächste Stufe ist die chemische und physikalische Funktionalisierung dieser Architekturen durch Einstellung ihrer Porositäten. Dieser Aufsatz konzentriert sich auf drei Aspekte von Koordinationspolymeren: 1) Anwendung von Kristall‐Engineering zum Aufbau poröser Gerüste aus Konnektoren und Linkern (“Nanospace‐Engineering”), 2) Charakterisierung und Katalogisierung porös‐struktureller Funktionalität für Anwendungen in Speicherungs‐, Austausch‐, Trennprozessen etc. und 3) porös‐strukturelle Funktionalität auf der Basis dynamischer Kristallumwandlungen durch Gastmoleküle oder physikalische Reize. Ziel ist es, den aktuellen Stand der Forschung zur Chemie und Physik von und in den Mikroporen poröser Koordinationspolymere vorzustellen.

Probing the Lewis Acidity and Catalytic Activity of the Metal–Organic Framework [Cu3(btc)2] (BTC=Benzene‐1,3,5‐tricarboxylate)

“…[1][2][3][4] In literature, the term MOF covers a wide assembly of hybrid compounds. [4,5] Because of the exceptionally high pore volume and surface area of MOFs, many research efforts have been spent to their application in the sorption of light gases, either as such [6][7][8][9][10] or after modification with, for example, Ba 2 + . [11] As porous materials, MOFs may also find applications in catalysis.…”

Hierarchical Self‐Assembly of One‐Dimensional Streptavidin Bundles as a Collagen Mimetic for the Biomineralization of Calcite

“…[51,[58][59][60][61][62][63][64][65][66][67][68] Reminiscent of collagen processing, [69] the approach delineated herein represents an example of hierarchical self-assembly in which each stage involves building blocks of increasing size such that the resulting supramolecular structure spans over six orders of magnitude, from nanometer-sized covalent building blocks to millimeter calcite wires. [70] We have demonstrated that streptavidin (the linker) combined with a linear tetrabiotinylated connector, the [Fe(Biot 2 -terpy) 2 ] 2+ complex, spontaneously self-assemble into a one-dimensional metal-organic protein framework. In the presence of calcium ions, these MOPFs form bundles that serve as a template for the biomineralization of calcite.…”

“…Such guest&host complexes often display unusual properties such as chemical reactivity, energy or electron transfer, second harmonic generation materials, high-capacity gas storage, catalysis, etc. [1][2][3][4][5][6] In parallel to these developments, surfaces and cavities spanned by protein higher-order aggregates have been exploited for molecular encapsulation and for templating nanoparticle synthesis. Typical examples include protein fibrils, [7,8] ferritin, [9,10] S-layers, [11][12][13] antibodies, [14] peptide amphiphiles, [15] capsids, [16][17][18][19] leucine zippers, [20] etc.…”

“…[42,43] For this proof-ofprinciple study, we selected a preorganized bis-biotinylated terpyridine ligand Biot 2 -terpy that binds to two cis-related sites in streptavidin. [44][45][46][47] A ferrous ion was chosen as terpyridine binds in a cooperative fashion (K 1 = 1.26 10 7 m À1 , K 2 = 6.31 10 13 m À1 ), [48] thus ensuring the exclusive formation of a linear connector bearing four biotin anchors ( Figure 2 2+ ion and Sav can be conveniently monitored with the disappearance of an induced CD signal, l max = 505 nm, caused by the displacement of 2-(4'-hydroxyazobenzene)benzoic acid (HABA, a hydrophobic dye weakly bound within the biotin-binding pocket) by the [Fe(Biot 2 -terpy) 2 ] 2+ ion (see the Supporting Information). [37,49] Upon standing at room temperature, the dilute purple solution containing the metal + ligand + protein triad slowly becomes turbid, suggesting the formation of polymeric material {[Fe(Biot 2 -terpy) 2 ] 2+ &Sav} 1 .…”

“…[21][22][23][24][30][31][32][33][34] In the spirit of coordination polymers, we reasoned that one may exploit the versatility of transition-metal connectors in conjunction with proteins bearing tethered ligands to create discrete one-, two-, or three-dimensional metalorganic protein frameworks (MOPF; Figure 1). For this proof-of-principle study, we used a linear Fe(terpy) 2 moiety (terpy = terpyridine) bearing four biotin anchors, [Fe(Biot 2 -terpy) 2 ] 2+ complex (the connector), in conjunction with streptavidin (hereafter referred to as Sav, the linker) to afford a one-dimensional MOPF. We show that in the presence of calcium ions and CO 2 -rich vapors, these MOPF aggregates form bundles that template the biomineralization of calcite.…”