Three-Component Self-Assembly Changes its Course: A Leap from Simple Polymers to 3D Networks of Spherical Host-Guest Assemblies

A lens-shaped supramolecule based on the bulky pentaphosphaferrocene [CpBIGFe(η5-P5)] and CuBr2

Besides inherent fullerene-like hollow spheres, the metallasupramolecular chemistry of pentaphosphaferrocenes and CuBr2 afforded a conceptually new product, a compact 3.2 nm sized supramolecule [{1d}6(CuBr)32(CH3CN)6] formed by six largest pentaphosphaferrocene units [CpBIGFe(η5-P5)] (1d: CpBIG = η5-C5(4-nBuC6H4)5) so far and a framework of 32 copper and 32 bromide ions.

Diantimony Complexes [CpR 2 Mo2 (CO)4 (μ,η2 -Sb2 )] (CpR =C5 H5 , C5 H4 t Bu) as Unexpected Ligands Stabilizing Silver(I)n (n=1-4) Monomers, Dimers and Chains

Synthesis and reactivity of transition metal compounds bearing "naked" pnictogen atoms is an active research area with remarkable bonding patterns observed in the formed compounds. Within this field, intense investigations on the coordination behavior of complexes possessing P_n and As_n (2≤n≤5) moieties have been conducted. However, studies on heavier analogues have been ignored so far due to arduous challenges related to low yields and moderate air stability. Herein, we present the first in-depth study addressing the reactivity of organometallic complexes containing Sb-donor atoms with several Ag^I salts. These reactions afforded twelve unprecedented aggregates as monomers, dimers as well as three- and four-membered chains of Ag^I ions claimed in the literature to be inaccessible. Interatomic distances as well as computational evidence obtained with help of several different methods suggest the presence of Ag⋅⋅⋅Ag interactions in all complexes containing more than one Ag^I ion.

Chain Length Effect on the Structural and Emission Properties of the CuI/Bis((4-methoxyphenyl)thio)alkane Coordination Polymers

A systematic chain length variation of the ligand para-MeOC₆H₄S(CH₂)_mSC₆H₄OMe (1 ≤ m ≤ 8) was performed to study its effect on the structures and photophysical properties of the coordination polymers (CP) when reacted with CuI. Indeed, direct correlations are noted between these features and m. When m is an odd number, the secondary building unit is systematically the common closed-cubane Cu₄I₄ cluster, rendering the material strongly luminescent (i.e., emission quantum yield, Φ_e > 20%), and the CP is one-dimensional (1D). However, when m is 2, 4, and 6, the SBUs exhibit rare polymeric motifs of (Cu₂I₂)_n: staircase ribbon, fused poly(rhombic pseudo-dodecahedron), and accordion ribbon, respectively, and the emission intensities are either very weak (Φ_e < 0.001%) or of medium intensity (Φ_e ∼ 10% when m = 6). When m = 8 (i.e. the most flexible chain), the SBU is a closed-cubane Cu₄I₄ and the emission intensity is medium (Φ_e ∼ 10%). A special case was observed for m = 3, where a co-crystallization of the molecular cluster Cu₄I₄(NCCH₃)₄ is observed in the lattice, which turns out to be quite important for the stability of the network.

Multifunctional Hyphae Carbon Powering Lithium-Sulfur Batteries

Biotechnology can bring new breakthroughs on design and fabrication of energy materials and devices. In this work, a novel and facile biological self-assembly technology to fabricate multifunctional Rhizopus hyphae carbon fiber (RHCF) and its derivatives on a large scale for electrochemical energy storage is proposed. Crosslinked hollow carbon fibers are successfully prepared by conversion of Rhizopus hyphae, and macroscopic production of centimeter-level carbon balls consisting of hollow RHCFs is further realized. Moreover, the self-assembled RHCF balls show strong adsorption characteristics on metal ions and can be converted into a series of derivatives such as RHCF/metal oxides. Notably, the designed RHCF derivatives are demonstrated with powerful multifunctionability as cathode, anode, and separator for lithium-sulfur batteries (LSBs). The RHCF can act as the host material to combine with metal oxide (CoO) and S, Li metal, and a polypropylene (PP) separator to form a new RHCF/CoO-S cathode, an RHCF/Li anode, and an RHCF/PP separator, respectively. Consequently, the optimized LSB full cell presents excellent cycling performance and superior high-rate capacity (881.3 mA h g^-1 at 1 C). This work provides a new method for large-scale preparation of hollow carbon fibers and derivatives for advanced energy storage and conversion.

Structural Chemistry of Giant Metal Based Supramolecules

The review presents a bird-eye view on the state of research in the field of giant nonbiological discrete metal complexes and ions of nanometer size, which are structurally characterized by means of single-crystal X-ray diffraction, using the crystal structure as a common key feature. The discussion is focused on the main structural features of the metal clusters, the clusters containing compact metal oxide/hydroxide/chalcogenide core, ligand-based metal-organic cages, and supramolecules as well as on the aspects related to the packing of the molecules or ions in the crystal and the methodological aspects of the single-crystal neutron and X-ray diffraction of these compounds.

Three-Component Self-Assembly Changes its Course: A Leap from Simple Polymers to 3D Networks of Spherical Host-Guest Assemblies

One‐pot self‐assembly reactions of the polyphosphorus complex [Cp*Fe(η⁵‐P₅)] (A), a coinage metal salt AgSbF₆, and flexible aliphatic dinitriles NC(CH₂)_xCN (x=1–10) yield 1D, 2D, and 3D coordination polymers. The seven‐membered backbone of the dinitrile was experimentally found as the borderline for the self‐assembly system furnishing products of different kinds. At x<7, various rather simple polymers are exclusively formed possessing either 0D or 1D Ag/A structural motifs connected by dinitrile spacers, while at x≥7, the self‐assembly switches to unprecedented extraordinary 3D networks of nano‐sized host–guest assemblies (SbF₆)@[(A)₉Ag₁₁]¹¹⁺ (x=7) or (A)@[(A)₁₂Ag₁₂]¹²⁺ (x=8–10) linked by dinitriles. The polycationic nodes represent the first superspheres based on A and silver and are host–guest able. All products are characterized by NMR spectroscopy, mass spectrometry, and single‐crystal X‐ray diffraction. The assemblies [(A)₁₂Ag₁₂]¹²⁺ were visualized by transmission electron microscopy.

Au-Containing Coordination Polymers Based on Polyphosphorus Ligand Complexes

Whereas the self-assembly of pentaphosphaferrocenes [Cp^RFe(η⁵-P₅)] (Cp^R = Cp*, Cp^×, and Cp^Bn) with Cu and Ag salts has been well-studied in the past, the coordination chemistry toward Au complexes has been left untouched so far. Herein, the results of the self-assembly processes of [Cp^RFe(η⁵-P₅)] with Au salts of different anions (GaCl₄^-, SbF₆^-, and Al(OC(CF₃)₃)₄ (TEF^-)) are reported. Next to a variety of molecular coordination products, the first coordination polymers based on polyphosphorus ligand complexes and Au salts are also obtained. Thereby, a 2D coordination polymer comprising metal vacancies is isolated. In all products, the Au centers are coordinated in a linear or a trigonal planar environment. In solution, highly dynamic processes are observed. Variable-temperature NMR spectroscopy, solid-state NMR spectroscopy, and X-ray powder diffraction were applied to gain further insight into selected coordination compounds.