New Functional Polymers and Materials Based on 2,2′:6′,2″‐Terpyridine Metal Complexes

New inorganic–organic hybrid structures based on metal complexes have become of increasing interest over the last few decades in the search for new materials. Many different polypyridyl metal complexes have been investigated. Recently, a strong increase in interest regarding 2,2′:6′,2″‐terpyridine has been observed. In particular, octahedral bis‐2,2′:6′,2″‐terpyridine metal complexes offer the advantages of increased symmetry and, in the case of ruthenium(III )/ruthenium(II ) complexation, an entrance to a directed complexation technique. Apart from the combination with polymeric systems, ordered inorganic–organic structures on surfaces are becoming better understood concurrently with the development of sophisticated nanotechnology characterization techniques. There are many ongoing efforts that include terpyridine complex structures, especially concerning photophysical processes such as solar light to energy conversion. This review deals with the incorporation of terpyridine complexes into polymeric structures such as poly(ethylene glycol), poly(styrene), dendrimers, biomacromolecules, micelles, and resins, as well as the combination of terpyridine complexes with surfaces for electrocatalytic, photophysical, and self‐assembly purposes.     

Mesogenic lanthanoid metal complexes of a non-mesogenic Schiff-base, N,N′-di-(4-hexadecyloxysalicylidene)-l′,8′-diamino-3′,6′-dioxaoctane

A non-mesogenic Schiff-base, N,N′-di-(4-hexadecyloxysalicylidene)-l′,8′-diamino-3′,6′-dioxaoctane, H₂dhdsdd (H₂L²), was synthesized, structure studied by elemental analyses and mass, NMR and IR spectra and ligated to some Ln^III metal ions that yielded mesogenic (SmA/N) Ln^III complexes of the general composition, [Ln₂(L²H₂)₃(NO₃)₄](NO₃)₂, where Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Ho. IR and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as L²H₂) to the Ln^III ions through two phenolate oxygens, rendering the overall geometry around Ln^III to distorted mono-capped octahedron.     

Investigations of MX and γ′/γ″ precipitates in the nickel-based superalloy 718 produced by electron beam melting

Samples with a composition similar to the nickel-based superalloy Inconel alloy 718 were produced by electron beam melting of prealloyed powder and investigated with respect to type and composition of the strengthening precipitates. The matrix consists of γ grains orientated in nearly the same direction, almost like a single crystal. Coarse precipitates (<2 μm), mostly of the (Ti,Nb)(C,N,B) type with B1 structure, are aligned along the growth direction. TEM and APFIM investigations of the γ matrix revealed very fine γ″ precipitates of around 5–10 nm in size. Additionally, at small angle grain boundaries, coarser γ″ precipitates of 50–100 nm in size have been observed. The 0 01 γ//0 0 1 γ″ and {1 0 0} γ//{1 0 0} γ″ orientation relationship between γ and γ″, known from literature [M. Sundararaman, P. Mukhopadhyay, Mater. Charact. 31 (1993) 191–196], was confirmed. Some γ′ precipitates of 2–5 nm in size were observed by means of FIM.     

Spectral characterization of electroluminescent devices containing functionalized dipyrido[3,2-a:2′,3′-c]phenazine complexes

A series of functionalized dipyrido[3,2-a:2′,3′-c]phenazine complexes with copper(I), rhenium(I), ruthenium(II) and iridium(III) have been synthesized and used as dopants in OLEDs. The ruthenium-based complexes are the most efficient appearing blue in colour, the copper complexes give devices that appear white in emission. In most cases the emission colour is a mixture of emission from the metal complex and from the matrix (PVK).     

Crystal structure of the orthorhombic U2-Al4Mg4Si4 precipitate in the Al–Mg–Si alloy system and its relation to the β′ and β″ phases

The atomic structure of a common precipitate in the Al–Mg–Si system has been determined. It is isotypic with TiNiSi (space group Pnma) and contains four units of MgAlSi in a unit cell of size a = 0.675 nm, b = 0.405 nm, c = 0.794 nm. EDS analyses support the composition. A model was based on the atomic structure of the β′ precipitate, electron diffraction and high-resolution transmission electron microscopy (HRTEM) images. A quantum mechanical refinement of the model removed discrepancies between simulated and experimental diffraction intensities. Finally, a multi-slice least square refinement confirmed the structure. The structural relation with β″ is investigated. A similar Mg–Si plane also existing in β″ and β′, can explain most coherency relations between the precipitate phases and with matrix.     

Dithieno[3,2‐b:2′,3′‐d]pyrrol Fused Nonfullerene Acceptors Enabling Over 13% Efficiency for Organic Solar Cells

A new electron‐rich central building block, 5,5,12,12‐tetrakis(4‐hexylphenyl)‐indacenobis‐(dithieno[3,2‐b:2′,3′‐d]pyrrol) (INP), and two derivative nonfullerene acceptors (INPIC and INPIC‐4F) are designed and synthesized. The two molecules reveal broad (600–900 nm) and strong absorption due to the satisfactory electron‐donating ability of INP. Compared with its counterpart INPIC, fluorinated nonfullerene acceptor INPIC‐4F exhibits a stronger near‐infrared absorption with a narrower optical bandgap of 1.39 eV, an improved crystallinity with higher electron mobility, and down‐shifted highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. Organic solar cells (OSCs) based on INPIC‐4F exhibit a high power conversion efficiency (PCE) of 13.13% and a relatively low energy loss of 0.54 eV, which is among the highest efficiencies reported for binary OSCs in the literature. The results demonstrate the great potential of the new INP as an electron‐donating building block for constructing high‐performance nonfullerene acceptors for OSCs.     

New 3-((2′:2″,5″:2-terthiophene)-3″-yl) acrylic acid as active layer for organic field-effect transistor

Most functionalized thiophenes are difficult to electropolymerize due to nucleophilicity that will attack the radical cation inhibiting polymerization. However, we have successfully electrodeposited a newly synthesized functionalized terthiophene monomer 3-((2′:2″,5″:2-terthiophene)-3″-yl) acrylic acid (TAA) as an active layer of a organic field-effect transistor (OFET). The polymer was then oxidized in order to increase its conductivity. Various oxidizing potentials were experimented and their effect on the OFET's charge mobility was examined. A mobility of 0.25 cm² (V s)⁻¹ is achieved with an oxidizing potential of 0.9 V after vacuum drying.     

Superlattice stacking fault formation and twinning during creep in γ/γ′ single crystal superalloy CMSX-4

This paper describes further insight which has been gained into the formation of deformation twins during high temperature creep in a high volume fraction single crystal superalloy (CMSX-4) and correlation with the nature of superlattice stacking faults also observed. In general it is found that the formation of high temperature twinning can always be associated with the loading orientation in which SESF formation is expected from a determination of the sign of the shear stress. One can rationalise the reason for this twinning being associated with extrinsic stacking faults, by consideration of the critical radius of stacking fault loop nucleation. In particular calculations at 1223 K demonstrate a minimum in radius being associated with four overlapping faulted planes for the extrinsic case. Although the process by which twin formation occurs has not been observed, it is shown that twin formation can take place by the passage of extrinsic stacking faults within the precipitate which operate on every alternate plane of the structure. If one considers formation to occur via a pole mechanism similar to that in a face centred cubic structure a mechanism for this occurrence is postulated due to the fact that climb of the helix structure as it rotates around a pair of suitable matrix dislocations, will amount to double that which occurs in the single pole case.     

Berechnung des (420)-Reflexprofiles einer γ′-Fe4N1−x-Schicht mit Säulenstruktur und Dehnungsrelaxation

Calculation of the (420)-reflection profile of a γ′-Fe₄N_1?x layer with columnar structure and strain relaxation A couple of surface treatments and thin film deposition methods lead to strained layers and columnar layer structure. Within the columns strain relaxation outwards along the column radius occurs. This relaxation causes asymmetrical broadening of X-ray reflections. A method is introduced, to calculate the reflection profiles of layers with columnar structure and strain relaxation. The possibility of a comparison between a calculated and a measured profile for the determination of the average column radius and the relaxation is discussed.     

Overlapping of γ′ precipitate variants in Inconel 718

In Inconel 718 alloy, different variants of γ′ precipitates often appear to intersect each other during their growth. Such apparent intersections are shown on the basis of structure factor contrast to be an overlapping effect.