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To probe the possibility that carbodicarbenes (CDCs) are redox active ligands, all four members of the redox series [Fe(1)2]n+ (n=2–5) were synthesized, where 1 is a neutral tridentate CDC. Through a combination of spectroscopy and DFT calculations, the electronic structure of the pentacation is shown to be [FeIII(1.+)2]5+ (S= (Formula presented.)). That of [Fe(1)2]4+ is more ambiguous, but it has significant contributions from the open-shell singlet [FeIII(1)(1.+)]4+ (S=0). The observed spin states derive from antiferromagnetic coupling of their constituent low-spin iron(III) centres and cation radical ligands. This marks the first time redox activity has been observed for carbones and expands the diverse chemical behaviour known for these ligands. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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Angewandte Chemie - International Edition

Observation of Carbodicarbene Ligand Redox Noninnocence in Highly Oxidized Iron Complexes

Inorganic Chemistry

Two-Dimensional and Emission-Tunable: An Unusual Perovskite Constructed from Lindqvist-Type [Pb<inf>6</inf>Br<inf>19</inf>]<sup>7-</sup> Nanoclusters

While manipulating the helicity of nanostructures is a challenging task, it attracts great research interest on account of its crucial role in better understanding the formation mechanisms of helical systems. For the supramolecular chirality in self-assembly systems, one challenge is how to understand the origin of supramolecular chirality and inherent helicity information on nanostructures regulated by functionality-oriented stacking modes (such as J- and H-aggregation) of building blocks. Herein, two-component hydrogels were prepared by phenylalanine-based enantiomers and achiral bis(pyridinyl) derivatives, where helical nanofibers with inverse handedness as well as controllable helical pitch and diameter were readily obtained through stoichiometric coassembly of these building blocks. The helix inversion was achieved by the transition between the J- and H-aggregation of bis(pyridinyl) derivatives, which was collectively confirmed by circular dichroism, scanning electron microscopy, Fourier transform infrared spectroscopy, and single X-ray crystallography. Interestingly, the helical coassemblies with opposite handedness could be obtained not only from the enantiomeric building blocks but also from the chiral monomers with the same configurational chirality by exchanging achiral additives. This work provides insight into the origin and helicity inversion of supramolecular chirality in molecular self-assembly systems and may shine light on the precise fabrication of chiral nanostructures for potential applications in smart display devices, optoelectronics, and biological systems. © 2018 American Chemical Society.

Journal of the American Chemical Society

Controlling Supramolecular Chirality of Two-Component Hydrogels by J- and H-Aggregation of Building Blocks

The metallostibine Os2(CO)8(μ-SbPh), 2, acts as a good two-electron donor ligand, reacting readily with Group 8 metal carbonyls to give heterometallic clusters. Specifically, it undergoes ligand substitution reaction with Fe2(CO)9, Os3(CO)11(CH3CN), or Os3(CO)10(CH3CN)2 to afford Os2Fe(CO)12(μ3-SbPh), 3, Os5(CO)19(μ3-SbPh), 4, or Os7(CO)26(μ3-SbPh)2, 5, respectively, in moderate to high yields. An analogous reaction with Ru3(CO)11(CH3CN) afforded another spirocyclic cluster Os3Ru(CO)14(μ-PhCO)(μ4-Sb), 9. UV irradiation of 4 afforded the spirocyclic clusters Os5(CO)18(μ,η2-PhCO)(μ4-Sb), 6, and Os5(CO)18(μ,η2-C6H4)(μ-H)(μ4-Sb), 7, while the raft-like cluster Os5(CO)19(μ3-SbPh), 8, was obtained when a methanolic solution was exposed to natural light; cluster 5 failed to react under similar conditions. All the new clusters have been characterized spectroscopically and crystallographically, and possible pathways for the formation of 6-9 proposed. © 2018 Elsevier B.V.

Journal of Organometallic Chemistry

The metallostibine Os2(CO)8(μ-SbPh): A versatile donor precursor for antimony-containing heterometallic clusters

Increasing the length of azaacene derivatives through quinone bridges is very important because these materials could have deep LUMO energy levels and larger overlapping in the solid state, which would have great applications in organic semiconducting devices. Here, two fully characterized large quinone-fused azaacenes Hex-CO and Hept-CO prepared through a novel palladium-catalyzed coupling reaction are reported. Our research clearly proved that the quinone unit can be employed as a bridge to extend the molecular conjugation length, increase the molecular overlapping, and engineer the molecular stacking mode. Hex-CO shows lamellar 2-D π-stacking modes, while Hept-CO shows 1-D π-stacking and adopts a 3-D interlocked stacking mode with the adjacent molecular layers vertical to each other. With the deep LUMO energy levels (∼-4.27 eV), Hex-CO and Hept-CO were both demonstrated to be electron-transport layers. Their charge transport properties were investigated through OFETs and theoretical calculations. Due to the different stacking modes, Hex-CO shows a higher electron mobility of 0.22 cm2 V-1 s-1 than Hept-CO (7.5 × 10-3 cm2 V-1 s-1) in a single-crystal-based OFET. Our results provide a new route for structure engineering through extending the azaacene derivatives by quinone bridges, which can be of profound significance in organic electronics. © 2018 The Royal Society of Chemistry.

Fulltext

Journal of Materials Chemistry C

Structure engineering: Extending the length of azaacene derivatives through quinone bridges

Deprotonation of 1-mesityl-4,5-diphenyl-2-imidazole 1 with nBuLi, followed by salt metathesis reaction with GeCl2·dioxane complex, led to the formation of the chlorogermyliumylidene 2 bearing two Ge–Cl units, which has been isolated and fully characterized by standard spectroscopic and X-ray diffraction analysis. Structural and NMR spectroscopic data as well as computational studies revealed that the positive charge mainly resides on the Ge atom between two nitrogen atoms. Reduction of 2 with an excess amount of lithium metal resulted in Ge–Ge bond formation concomitant with elimination of one of the Ge atoms of 2, to give rise to the digermylenedilithium compound 3 involving intramolecular coordination of the imines and the lone pairs to the Li atoms. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

European Journal of Inorganic Chemistry

Isolation and Reactivity of a Chlorogermyliumylidene Featuring Two Ge–Cl Units

A new crystal phase of a naphthalenediimide derivative (α-DPNDI) has been prepared via a facial polymer-assisted method. The stacking pattern of DPNDI can be tailored from the known one-dimensional (1D) ribbon (β phase) to a novel two-dimensional (2D) plate (α phase) through the assistance from polymers. We believe that the presence of polymers during crystal growth is likely to weaken the direct π-π interactions and favor side-to-side C-H-π contacts. Furthermore, β phase architecture shows electron mobility higher than that of the α phase in the single-crystal-based OFET. Theoretical calculations not only confirm that β-DPNDI has an electron transport performance better than that of the α phase but also indicate that the α phase crystal displays 2D transport while the β phase possesses 1D transport. Our results clearly suggest that polymer-assisted crystal engineering should be a promising approach to alter the electronic properties of organic semiconductors. © 2018 American Chemical Society.

ACS Applied Materials and Interfaces

Polymer-Assisted Single Crystal Engineering of Organic Semiconductors to Alter Electron Transport

Herein we describe that oxidation reactions of the dimeric cyclophosphazanes, [{P(μ-NR)}2(μ-NR)]2, R =tBu (1), to produce a series of diagonally dioxidized products P4(μ-NtBu)6E2 [E = O (2), S (3), and Se (4)] and tetraoxidized frameworks. The latter display an unexpected C-N bond activation and cleavage to produce a series of novel phosphazane macrocyclic arrangements containing newly formed N-H bonds. Macromolecules P4(μ-NtBu)4(μ-NH)2O4 (5) and P4(μ-NtBu)3(μ-NH)3E4, E = S (6) and Se (7), dicleaved and tricleaved products, respectively, are rare examples of dimeric macrocycles containing NH bridging groups. Our theoretical and experimental studies illustrate that the extent to which these C-N bonds are cleaved can be controlled by modification of steric parameters in their synthesis, by adjusting either the steric bulk of the substituents in the parent framework or the size of the chalcogen element introduced during the oxidation process. Our findings represent new synthetic pathways for the synthesis of otherwise-elusive macrocycle arrangements within the phosphazane family. Copyright © 2018 American Chemical Society.

Synthesis of Unique Phosphazane Macrocycles via Steric Activation of C-N Bonds

Developing novel lanthanide metal-organic frameworks (Ln-MOFs) to rapidly and reliably differentiate both metal ions in solution and volatile organic compounds (VOCs) in vapor is highly challenging. Here, we describe versatile Eu3+/Tb3+-MOFs based on a flexible ligand. It is noteworthy that the film fabricated using bimetallic Eu0.47Tb0.63-MOF and polyvinyl alcohol could serve as an easy and convenient luminescent platform for distinguishing different metal ions and VOCs. The luminescent film exhibits notable fingerprint correlation between the metal ions/VOCs and the emission intensity ratio of Eu3+/Tb3+ ions in Ln-MOFs. As a result, the bimetallic Ln-MOFs show fast recognition of Fe3+ ion with a response time of &lt;10 s, and can effectively probe styrene vapor within 4 min. Since the developed Ln-MOF film is stable and reliable, this work presents a promising strategy to explore luminescent platforms capable of effectively sensing different metal ions and VOCs. © 2018, The Author(s).