Non-spherical nanostructures derived from soft matter and with uniform size-that is, monodisperse materials-are of particular utility and interest, but are very rare outside the biological domain. We report the controlled formation of highly monodisperse cylindrical block copolymer micelles (length dispersity < or = 1.03; length range, approximately 200 nm to 2 microm) by the use of very small (approximately 20 nm) uniform crystallite seeds that serve as initiators for the crystallization-driven living self-assembly of added block-copolymer unimers with a crystallizable, core-forming metalloblock. This process is analogous to the use of small initiator molecules in classical living polymerization reactions. The length of the nanocylinders could be precisely controlled by variation of the unimer-to-crystallite seed ratio. Samples of the highly monodisperse nanocylinders of different lengths that are accessible using this approach have been shown to exhibit distinct liquid-crystalline alignment behaviour.

Metal-containing polymers are attracting growing attention as functional materials as a result of the useful physical and catalytic properties that arise from the presence of metal centers.[1] For example, metallopolymers with reversible redox properties are of interest for applications in electrocatalysis [2] and sensing, [3] as responsive surfaces [4] and capsules, [5] and as the active components of photonic crystal displays.[6] Block copolymers containing metal centers present additional features of considerable interest as a result of their ability to undergo self-assembly in the solid state or solution. Studies of such materials have led to applications as nanotemplates in lithography [7] and as precursors to patterned magnetic nanostructures [8] and nanocatalysts for carbon nanotube growth.[9] However, the synthesis of materials containing metalloblocks by living polymerization protocols presents substantial challenges as a result of undesirable side reactions of many metal centers with ionic and radical propagating sites. Herein, we describe our initial results on the synthesis and properties of unusual main-chain heterobimetallic diblock copolymers with different redox-active centers in each metalloblock.The ring-opening polymerization (ROP) of strained metallocenophanes 1 provides a well-studied route to functional metallopolymers 2. [10][11][12] In particular, the ROP of 18-electron sila[1]ferrocenophanes (1, M= Fe, E x R y = SiR 2 ) represents a useful route to polyferrocenylsilanes (PFSs, 2, M = Fe, E x R y = SiR 2 ) which exhibit many interesting characteristics.[13] Living anionic polymerization of sila[1]ferrocenophanes (1, M = Fe, E x R y = SiR 2 ) using organolithium initiators such as nBuLi proceeds by cleavage of the Si-Cp bond (Cp = cyclopentadienyl), and has been developed as a route to a variety of PFS block copolymers.[14] An alternative procedure, living photocontrolled ROP in the presence of cyclopentadienide anion initiators, [15] involves photoactivation and subsequent cleavage of the Fe-Cp bond. + homopolymer and also ring-opening oligomerizations of 3 appeared to proceed through Co-Cp bond cleavage. [19] The successful synthesis of PFS-b- [PCE] + block copolymers was accomplished by sequential photocontrolled ROP of 1 (M = Fe, E x R y = SiMe 2 ) and 3 followed by oxidation of the 19-electron cobaltocene centers (Scheme 1). [19][20][21][22] The living PFS blocks were synthesized by addition of sodium cyclopentadienide (NaCp) as initiator to a solution of 1 (M = Fe, E x R y = SiMe 2 ) in tetrahydrofuran (THF) under anhydrous conditions, followed by prolonged irradiation (5-24 h) of the solutions at 5 8C. The living PFS chains were then combined with 19-electron cobaltocenophane 3, and the solutions irradiated at 20 8C (to increase solubility) until the block copolymers precipitated from solution (15-24 h). The living polymer chains were quenched by, and the resulting product washed with degassed methanol, oxidized by air in the presence of ammonium triflate ([NH 4 ][OTf]), and dia...

Cryo-electron tomography (cryo-ET) is a groundbreaking technology for 3D visualisation and analysis of biomolecules in the context of cellular structures. It allows structural investigations of single proteins as well as their spatial arrangements within the cell. Cryo-tomograms provide a snapshot of the complex, heterogeneous and transient subcellular environment. Due to the excellent structure preservation in amorphous ice, it is possible to study interactions and spatial relationships of proteins in their native state without interference caused by chemical fixatives or contrasting agents. With the introduction of focused ion beam (FIB) technology, the preparation of cellular samples for electron tomography has become much easier and faster. The latest generation of integrated FIB and scanning electron microscopy (SEM) instruments (dual beam microscopes), specifically designed for cryo-applications, provides advances in automation, imaging and the preparation of high-pressure frozen bulk samples using cryo-lift-out technology. In addition, correlative cryofluorescence microscopy provides cellular targeting information through integrated software and hardware interfaces. The rapid advances, based on the combination of correlative cryo-microscopy, cryo-FIB and cryo-ET, have already led to a wealth of new insights into cellular processes and provided new 3D image data of the cell. Here we introduce our recent

Raman spectra have been collected using three excitation wavelengths for thirteen uranyl mineral samples, including novác̆ekite, and analysed.