Structure and Reactivity of a Unique Y‐Shaped Tricoordinate Bis(silyl)platinum(II)–NHC Complex

Y not? A unique, three‐coordinate Y‐shaped bis(silyl)platinum(II) complex was isolated and characterized (see structure; C light gray, N blue, Si pink, Pt dark gray). DFT studies on a model system shed light on the nature of this unusual coordination mode for platinum(II).

     

Self‐Assembly and Structure of Cobalt(II) Complexes Using Diaminodiamide Ligands

The self‐assembly of Co(II) with two diaminodiamide ligands, 4,7‐diazadecanediamide and 4,8‐diazaundecanediamide, gave two different crystals, [(C₈H₁₈N₄O₂)Co(OH)₂Co(C₈H₁₈N₄O₂)]Cl₂ ( 1 ) [Co(C₉H₂₀N₄O₂)(Cl)(H₂O)]·Cl·2H₂O ( 2 ). Structures of 1 and 2 were characterized by single‐crystal X‐ray diffraction analysis. Structural data for 1 shows a novel type of binuclear complex with distorted octahederal coordination geometry around the Co atoms through the hydroxo bridges. By using inter‐connector N‐H···N hydrogen bonding interactions as building forces, each cationic moiety [(C₈H₁₈N₄O₂)Co(OH)₂Co(C₈H₁₈N₄O₂)]²⁺ is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chain‐like structure. The chains are further connected into a 2D layer in a (4,4)‐topology via N‐H···Cl_free hydrogen‐bonding interactions. Structural data for 2 indicate that the cobalt atom adopts a six‐coordinated N₂O₄ environment, giving a distorted octahedral geometry, where two N‐ and two O‐donor sets of ligand located at equatorial positions and one water and one chloride occupied at axial positions. Through NH···Cl‐Co and OH···Cl‐Co contacts, each cationic moiety [Co(C₉H₂₀N₄O₂)(Cl)(H₂O)]⁺ in 2 is linked to neighboring ones, producing a charged hydrogen‐bonded 1D chainlike structure. Thus, the crystal‐engineering approach has proved successful in the solid‐state packing due to steric strain effect of the diaminodiamide ligand.     

Mono‐ and Binuclear Dimethylthallium(III) Complexes with o‐Benzoquinone‐TTF‐o‐Benzoquinone Ligand; Synthesis,Spectroscopy and X‐ray Study

The new mono‐ and binuclear semiquinonato dimethylthallium complexes (Q‐TTF‐SQ)TlMe₂ ( 1 ) and Me₂Tl(SQ‐TTF‐SQ)TlMe₂ ( 2 ) based on di‐o‐quinone with tetrathiafulvalene (TTF) bridge, 4,4′,7,7′‐tetra‐tert‐butyl‐2,2′‐bis‐1,3‐benzodithiol‐5,5′,6,6′‐tetraone Q‐TTF‐Q, were synthesized by the reaction between corresponding mono‐ and di‐sodium semiquinonates (Q‐TTF‐SQ)Na and Na(SQ‐TTF‐SQ)Na and one or two equivalents of Me₂TlCl, respectively. The same products could be obtained by the interaction of Q‐TTF‐Q with one or two equivalents of Me₃Tl. Complexes 1 and 2 were characterized by IR and electronic absorption spectroscopy, EPR, and magnetic measurements. The molecular structures of 1 and 2 were determined by single‐crystal X‐ray diffraction. It was found that mono‐semiquinonato derivative 1 partially disproportionates into Q‐TTF‐Q and binuclear complex 2 in THF solution. According to variable temperature magnetic susceptibility measurements and EPR data, compound 1 reveals paramagnetic behavior with an S = 1/2 state in the range 50–300 K, whereas compound 2 has an S = 0 ground state as the consequence of antiferromagnetic coupling between semiquinonato moieties realized through the TTF‐bridge.     

Solution‐Processable n‐Type Organic Field‐Effect Transistor (OFET) Materials Based on Carbonyl‐Bridged Bithiazole and Dioxocyclopentene‐Annelated Thiophenes

A series of electronegative π‐conjugated compounds composed of carbonyl‐bridged bithiazole and alkyl‐substituted dioxocyclopenta[b]thiophene were synthesized as a candidate for solution‐processable n‐type organic semiconductor materials and characterized on the basis of photophysical and electrochemical properties. Cyclic voltammetry measurements showed that the first half‐wave reduction potentials of these compounds are between −0.97 and −1.14 V versus ferrocene/ferrocenium, which corresponds to lowest unoccupied molecular orbital energy levels between −3.83 and −3.66 eV. Thanks to hexyl or dodecyl groups in the molecules, the compounds are sufficiently soluble to realize the fabrication of their thin films through a spin‐coating method. As a result, the prepared organic field‐effect transistors based on these newly developed compounds exhibited n‐channel characteristics not only under vacuum but also in air, and the best field‐effect electron mobility observed under vacuum was 0.011 cm² V⁻¹ s⁻¹ with an on/off ratio of 10⁸ and a threshold voltage of 16 V.     

Helical Coordination Polymers Based on A Tripodal N‐donor Ligand

The coordination polymers [Cu₂(tpim)₂] · 2H₂O ( 1 ) and [Co(H₂tpim)₂(MoO₄)₂] ( 2 ) [Htpim = 2,4,5‐tri(4‐pyridyl)‐imidazole] were synthesized. Their structures were determined by single‐crystal X‐ray diffraction and further characterized by elemental analyses, IR spectroscopy, and TG analyses. Compounds 1 and 2 both contain chiral helical‐layer structures. Compound 1 exhibits a novel 3D (3,3,4)‐connected framework with (4 · 6 · 8)(6 · 8²)(4 · 6 · 8³ · 10) topology, which is constructed from left‐ and right‐ helices. Compound 2 displays a 2D chiral helical‐layer structure which can be rationalized as a (3,6)‐connected 2D kgd (kagome dual) net, and these 2D layers are further extended by hydrogen‐bonding interactions to form a 3D supramolecular network. By comparing compounds 1 and 2 , it is believed that the tripodal N‐containing ligand (Htpim) plays a key role in the construction of helical coordination polymers. In addition, the photoluminescence property of compound 1 and the magnetic property of compound 2 were studied.     

Synthesis,Structure and High Thermal Stability of a Novel Three‐dimensional Zinc(II) Complex with an Unsymmetrical Rigid‐flexible Ligand

A novel metal‐organic framework, [Zn(C₁₀H₈O₅)]_n ( 1 ) (C₁₀H₈O₅ = 2‐(4‐carboxylatophenoxy)propionate), was synthesized and characterized by elemental analysis, IR spectroscopy, X‐ray crystallography and thermogravimetric analysis. The crystal structure study reveals that each zinc atom is coordinated by four oxygen atoms from four different ligands to obtain a distorted tetrahedron. The rigid carboxyl group bridges two adjacent zinc atoms to form a dimer of eight‐membered rings, whereas the flexible carboxyl group bridges two adjacent dimers to form 1D chains along the a axis. Two adjacent 1D chains are interconnected by the ligands to produce 2D layers. These layers are further stabilized by intermolecular hydrogen bonds to construct a 3D framework showing high thermal stability (445 °C).     

A Highly Stable 3D Porous Lanthanum Metal‐organic Framework Constructed From A New Flexible Bis(benzoic acid) Ligand Produced in Situ

By employing diethyl 1,3‐propylidenebis(4‐oxybenzoate) as a precursor, the new three‐dimensional metal‐organic framework [La₂L₂(HL)₂]_n [L = 1,3‐propylidenebis(4‐oxybenzoate)] was prepared and characterized by single‐crystal X‐ray diffraction analysis, elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The compound crystallizes in the triclinic space group P , with cell parameters: a = 8.299 (2) Å, b = 14.127 (3) Å, c = 14.520 (3) Å, α = 112.43 (3) °, β = 103.10 (3) °, γ = 95.28 (3)°, V = 1502.2 (5) Å³, and Z = 1. Under hydrothermal reaction conditions, two ester groups of the ligand hydrolyzed into carboxylate groups. The carboxylate groups coordinated in situ to metal ions to form the 3D coordination polymer. It exhibits a 10.4 × 10.6 Å rhombic channel along the [011] direction. On the basis of the results of TG analysis, the structure is thermally stable up to ≈? 400 °C.     

Re‐Determination of the Crystal Structure of MIL‐91(Al)

The structure of one of the first permanently porous metal phosphonates, MIL‐91(Al) was re‐determined using high resolution synchrotron powder X‐ray diffraction data. The new model is in a lower symmetry space group, with no disordered ligands in the structure, whilst remaining otherwise consistent with the reported compound. New milder synthetic conditions were also developed.     

Nitrogen‐Rich Alkali Metal Salts (Na and K) of [Bis(N,N‐bis(1H‐tetrazol‐5‐yl)amine)‐zinc(II)] Anion: Syntheses,Crystal Structures,and Energetic Properties

Two nitrogen‐rich alkali metal salts based on nitrogen‐rich anion [Zn(bta)₂]^2–: {[Na₂Zn(bta)₂(H₂O)₈] · H₂O}_n ( 1 ) and {[K₂Zn(bta)₂(H₂O)₄]}_n ( 2 ) were synthesized by reactions of alkali hydroxide, N,N‐bis(1H‐tetrazol‐5‐yl)amine (H₂bta), and zinc chloride in aqueous solutions. The crystal structures of 1 and 2 were determined by low temperature single‐crystal X‐ray diffraction and fully characterized by elemental analysis and FT‐IR spectroscopy. The structures demonstrate that an infinite 1‐dimensional (1D) chain structure is constructed by Na⁺ ions and bridging water molecules in compound 1 , which is connected by extensive hydrogen bonds forming a complex 3D network, whereas compound 2 features a more complicated 3D metal‐organic framework (MOF). The thermal behaviors of 1 and 2 were investigated by differential scanning calorimetry (DSC) measurements. The DSC results illustrate that both compounds exhibit high thermal stabilities (decomposition temperature > 345 °C). In addition, the heats of formation were calculated on the basis of the experimental constant‐volume energies of combustion measured by using bomb calorimetry. Lastly, the sensitivities towards impact and friction were assessed according to Bundesamt für Materialforschung (BAM) standard methods.     

Unravelling the Correlation between Charge Mobility and Cocrystallization in Rod–Rod Block Copolymers for High‐Performance Field‐Effect Transistors

Cocrystallization involving two or more components aggregating into cocrystals allows the preparation of materials with markedly improved charge mobility. This approach however, is little explored in all‐conjugated block copolymers (BCPs). Herein, we report the first investigation into the correlation between cocrystals and charge mobility in a series of new all‐conjugated BCPs: poly(3‐butylthiophene)‐b‐poly(3‐hexylselenophene) (P3BT‐b‐P3HS) for high‐performance field‐effect transistors. These rationally synthesized rod–rod BCPs self‐assemble into cocrystals with high charge mobilities. Upon one‐step thermal annealing, their charge mobilities decrease slightly despite their increased crystallinities. After two‐step thermal annealing, P3BT‐b‐P3HS (P3BT/P3HS=2:1) and (1:1) cocrystals disappear and phase separation occurs, leading to greatly decreased charge mobilities. In contrast, P3BT‐b‐P3HS (1:2) retains its cocrystalline structure and its charge mobility.     

Bis(5,7‐dimethyl‐8‐hydroxyquinolinato)platinum(II) Complex for Efficient Organic Heterojunction Solar Cells

Organic photovoltaic (OPV) cells using metal(II) (Pt, Pd, Cu, and Ni) chelates of 8‐hydroxyquinoline (Hq) or 5,7‐dimethyl‐8‐hydroxy‐quinoline (HMe₂q) as an electron donor were fabricated by vacuum deposition. The bis(5,7‐dimethyl‐8‐hydroxyquinolinato)platinum(II) [Pt(Me₂q)₂]‐based OPVs showed the best performance with an open voltage (V_OC) of 0.42 V, a short circuit current density (J_SC) of 14.8 mA cm^?2, and a maximum power conversion efficiency (η_P) of 2.4 %. The X‐ray single‐crystal structures together with the grazing incidence X‐ray diffraction (GIXRD) data of thin film samples reveal that the peripheral methyl substituent(s) and platinum(II) ion are essential for the high degree of film crystallinity resulting in improved performance of the as‐fabricated field‐effect transistors (FETs) and OPV cells.     

Structural transitions of nanocrystalline domains in regioregular poly(3‐hexyl thiophene) thin films

The effects of solution processing and thermal annealing on thin film morphology and crystalline structures of regioregular poly(3‐hexyl thiophene) (RR P3HT) are studied in terms of molecular weight (M_w). Using grazing‐incidence X‐ray diffraction, π‐conjugated planes in drop‐cast films from chloroform solutions are found to be preferentially oriented parallel to the substrates regardless of M_w. However, the mesoscale nanocrystalline morphology of the drop‐cast films is significantly affected by M_w, exhibiting a distinctive morphological transition from short nanorods to long nanofibrils above a critical number‐averaged M_w (～ 3.6 kDa). This is probably due to the change in a conformation change from an extended‐chain to a folded‐chain, as M_w of RR P3HT increases. In contrast, spin‐casting of high M_w RR P3HT produces less ordered films with a lower crystallinity and mixed parallel/perpendicular orientations of π‐conjugated planes. The crystallinity and parallel π‐conjugated orientation of RR P3HT in spin‐cast films could be improved by thermal treatments at high‐temperatures either (1) above the glass transition temperature or (2) above the melting temperature of RR 3PHT followed by recrystallization upon cooling under vacuum. However, the charge mobility of the spin‐cast films for a field‐effect transistor application is still lower than that of the drop‐cast films. This would be attributed to the chain oxidation and the development of distinct grain boundaries between RR P3HT nanofibrils during the thermal treatments. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1303–1312, 2007     

A Tin(IV) Porphyrin with Two Axial Organometallic NCN‐Pincer Platinum Units

A tin(IV) porphyrin was combined with two axial NCN‐pincer platinum(II) fragments by utilizing the oxophilicity of the apical positions on the tin atom and the acidic nature of the NCN‐pincer platinum derived benzoic acid. The solid‐state structure determined by X‐ray crystallography revealed some close contacts between the pincer complexes and the meso‐p‐tolyl subsitutents of the porphyrin. It was shown by ¹H NMR spectroscopy that these close contacts were not present in solution and that this compound can potentially act as a novel building block for supramolecular architectures.     

Sulfur‐Assisted Intermolecular Triphenylphosphine Dissociation of Thiocarbamoyl Ligand in Platinum(II). X‐ray Structure of Complex [Pt(PPh3)2(η1‐SCNMe2)(Cl)]

Treatment of Pt(PPh₃)₄ with N,N‐dimethylthiocarbamoyl chloride, Me₂NC(=S)Cl, in dichloromethane at ?20 °C processes the oxidative addition reaction to produce platinum complex [Pt(PPh₃)₂(η¹‐SCNMe₂)(Cl)], 2 with releasing two triphenylphosphine molecules. The ³¹P{¹H} NMR spectra of complex 2 shows the dissociation of the triphenylphosphine ligand to form diplatinum complex [Pt(PPh₃)Cl]₂(μ,η²‐SCNMe₂)₂, 3 in which the two SCNMe₂ ligands coordinated through carbon to one metal center and bridging the other metal through sulfur. Complex 2 is characterized by X‐ray diffraction analysis.     

A New Chair‐shaped Conformation Containing HgHgOHgHgO: Synthesis and Structure of Hg4(L2)2(NO3)4 (L2 = morpholin‐4‐ylpyridin‐2‐ylmethyleneamine)

. The complex Hg₄(L²)₂(NO₃)₄ ( 1 ) (L² = morpholin‐4‐ylpyridin‐2‐ylmethyleneamine) has been synthesized and characterized by CHN analysis, IR, and UV/Vis spectroscopy. The crystal structure of 1 was determined using single‐crystal X‐ray diffraction. The crystal structure of 1 contains four mercury atoms, four nitrate anions (two terminal and two bridge ones) and two L² ligand molecules. A chair shape, six‐membered ring is formed with the sequence OHgHgOHgHg built from Hg–Hg dumbbells and oxygen atoms from the nitrate co‐ligands. In the crystal structure, the asymmetric unit of the compound is built up by one‐half of the molecule. It contains the Hg₂²⁺ moiety with a mercury–mercury bonded core, in which one diimine ligand is coordinated to one of the mercury atoms. The nitrate anions act as anisobidentate and bidentate ligands.     

Packing Studies on Poly(di‐n‐alkylsilylenemethylene)s

The packing of poly(di‐n‐alkylsilylenemethylene) (PDASMs) chains was studied by using X‐ray, electron diffraction, and molecular modeling methods. X‐ray and electron diffraction measurements revealed unit cells in which the PDASMs were efficiently packed. The PDASM with the longer alkyl side chains, such as poly(di‐n‐propylsilylenemethylene) (PDPrSM), showed packing with the alkyl side chains interlocked with each other like cross‐shaped gears in the two‐dimensional monoclinic unit cell. The PDASM with the shorter ethyl substituent, poly(di‐n‐ethylsilylenemethylene) (PDESM), showed a lack of ability to interlock its side chains due to the short length of the alkyl groups. In these studies, we found that the length of the alkyl side chains could change the packing arrangement of PDASMs from monoclinic to orthorhombic to hexagonal with only short‐range order as the alkyl side chain length decreases at room temperature.

The ab projection of a 4 × 4 chain array of poly(di‐n‐propylsilylenemethylene) (PDPSM) in the monoclinic unit cell.     

Crystal Structure and Magnetic Properties of Copper(II) and Nickel(II) Binuclear Complexes with Bisacylhydrazones Based on 2,6‐Diformyl‐4‐methylphenol

The series of binuclear Cu(II) and Ni(II) complexes with an asymmetrical exchange fragment based on 2,6‐diformyl‐4‐methylphenol bishydrazone has been synthesized for the first time. The compositions and structures of both ligands and its complexes have been established with the data of IR, ¹H NMR, and extended X‐ray absorption fine structure (EXAFS) spectroscopical studies as well as magnetic measurements. The structure of [Ni₂L₃(μ‐Pz)] · 2CH₃OH (L = triply deprotonated form of bishydrazone, Pz = pyrazol) was confirmed by X‐ray crystallographic analysis. In this complex, the coordination environment of two nickel ions is quite different, one nickel atom is square‐planar and the other is distorted octahedral coordinated. The values of exchange parameter calculated in terms of HDVV theory have been compared with the features of an asymmetrical exchange fragment's electronic and geometrical structure.