Jing Xiang

Metallopolymers for energy production, storage and conservation

With the worldwide awareness of the energy crisis and low carbon economy, there is an ever-growing demand for renewable energy resources, energy saving products and reliable energy storage devices. Metallopolymers play an increasingly important role as functional materials for energy production, conservation and storage. In this review, we explore the recent advances of metallopolymers in the areas of organic solar cells, white light organic light-emitting diodes and lithium-ion batteries. The structure–property relationship of these polymers and their device performances are paid special attention and described.

Ferrocene-containing poly(fluorenylethynylene)s for nonvolatile resistive memory devices

Four new conjugated ferrocene-containing poly(fluorenylethynylene)s (PFcFE1–PFcFE4) with triphenylamine, carbazole or thiophene moieties in the main chain have been designed and synthesized via a Sonogashira coupling reaction. Their structures, molecular weights, optical features, thermal properties and memory performance were well studied. Two terminal single layer devices (ITO/polymer/Al) based on PFcFE1, PFcFE2 and PFcFE3 exhibited flash memory behaviours, while PFcFE4 shared the common characteristics of the “write-once read-many times” (WORM) memory effect. These results would provide a new series of ferrocene-containing conjugated polymers with further opportunities for memory applications.

A novel tricyanoruthenium(III) building block for the construction of bimetallic coordination polymers

Reaction of excess cyanide with a ruthenium(VI) nitrido complex bearing a tridentate Schiff base ligand produces a novel tricyanoruthenium(III) complex in which nucleophilic substitution of an imine hydrogen of the Schiff base by cyanide has occurred, this complex is a useful building block for the construction of 3d-Ru(III) magnetic materials.

Reaction of an Osmium(VI) Nitrido Complex with Cyanide: Formation and Reactivity of an Osmium(III) Hydrogen Cyanamide Complex

Reaction of [Os(VI)(N)(L(1))(Cl)(OH(2))] (1) with CN(-) under various conditions affords (PPh(4))[Os(VI)(N)(L(1))(CN)(Cl)] (2), (PPh(4))(2)[Os(VI)(N)(L(2))(CN)(2)] (3), and a novel hydrogen cyanamido complex, (PPh(4))(2)[Os(III){N(H)CN}(L(3))(CN)(3)] (4). Compound 4 reacts readily with both electrophiles and nucleophiles. Protonation and methylation of 4 produce (PPh(4))[Os(III)(NCNH(2))(L(3))(CN)(3)] (5) and (PPh(4))[Os(III)(NCNMe(2))(L(3))(CN)(3)] (6), respectively. Nucleophilic addition of NH(3), ethylamine, and diethylamine readily occur at the C atom of the hydrogen cyanamide ligand of 4 to produce osmium guanidine complexes with the general formula [Os(III){N(H)C(NH(2))NR(1)R(2)}(L(3))(CN)(3)](-) , which have been isolated as PPh(4) salts (R(1) = R(2) = H (7); R(1) = H, R(2) = CH(2)CH(3) (8); R(1) = R(2) = CH(2)CH(3) (9)). The molecular structures of 1-5 and 7 and 8 have been determined by X-ray crystallography.

Novel heterobimetallic ruthenium(III)–cobalt(II) compounds constructed from trans-[RuIII(Q)2(CN)2] (Q = 8-quinolinolato): synthesis, structures and magnetic properties

Reaction of [Ru(II)(PPh(3))(3)Cl(2)] with HQ and KCN produces a new dicyanoruthenium(III) building block, [Ru(III)(Q)(2)(CN)(2)](-). It reacts with hydrated CoCl(2) in MeOH or DMF to produce a trinuclear compound 2 or a 1-D zigzag chain 3.

Luminescence behaviour of Pb2+-based cage-containing and channel-containing porous coordination polymers

Luminescent porous coordination polymers, cage-containing chains [Pb5(L1)6(N3)2(OH)2]n (1) and 1-D double helical chains [Pb(L2)(N3)]n (2) with 1-D channels were prepared by solvothermal reactions. These polymers can take up metal ions and induce different luminescence responses depending on the metal ions.

Addition of [CH(CN)2]− and [TCNE]˙− to RuVIN bearing 8-quinolinolato ligands

Reaction of Ru(VI)≡N complexes bearing 8-quinolinolato ligands with NCCH(2)CN/piperidine and NaTCNE afford novel ruthenium(ii) dicyanoimine and diimine/imino-oxazolone complexes, respectively.

Synthesis, structures and photophysical properties of luminescent cyanoruthenate(II) complexes with hydroxylated bipyridine and phenanthroline ligands

Treatment of (PPh4)2[RuII(PPh3)2(CN)4] (1) with bpyOH and phenOH in DMF afforded two mononuclear compounds fac-(PPh4)[RuII(bpyOH)(PPh3)(CN)3] (2) and fac-(PPh4)[RuII(phenOH)(PPh3)(CN)3] (3), respectively (bpyOH = 6-hydroxy-2,2′-bipyridine; phenOH = 2-hydroxy-1,10-phenanthroline). These complexes have been characterized by various spectroscopic techniques. The structures of 1 and 2 have also been determined by X-ray crystallography. Their photophysical and electrochemical properties have been investigated. Compound 3 displays intense emission with much higher quantum efficiency (Φem = 19.4%) in solution, compared with other related ruthenate(II) diimine complexes. In addition, their solvatochromism, pH effects, and ion perturbation have also been investigated. The different photoluminescent behaviors between these complexes and the previously reported complex [RuII(phen)(PPh3)(CN)3]− suggest that the introduction of the hydroxyl group into the diimine ligand would significantly affect their emission properties. Through spectrophotometric titrations, the ground state pKa and excited state pKa* values, as well as the dynamic pH response ranges of these complexes have been determined. Their photophysical response towards various metal ions have also been studied.

Aerobic Oxidation of an Osmium(III) N-Hydroxyguanidine Complex To Give Nitric Oxide

The aerobic oxidation of the N-hydroxyguanidinum moiety of N-hydroxyarginine to NO is a key step in the biosynthesis of NO by the enzyme nitric oxide synthase (NOS). So far, there is no chemical system that can efficiently carry out similar aerobic oxidation to give NO. We report here the synthesis and X-ray crystal structure of an osmium(III) N-hydroxyguanidine complex, mer-[Os(III){NH═C(NH2)(NHOH)}(L)(CN)3](-) (OsGOH, HL = 2-(2-hydroxyphenyl)benzoxazole), which to the best of our knowledge is the first example of a transition metal N-hydroxyguanidine complex. More significantly, this complex readily undergoes aerobic oxidation at ambient conditions to generate NO. The oxidation is pH-dependent; at pH 6.8, fac-[Os(NO)(L)(CN)3](-) is formed in which the NO produced is bound to the osmium center. On the other hand, at pH 12, aerobic oxidation of OsGOH results in the formation of the ureato complex [Os(III)(NHCONH2)(L)(CN)3](2-) and free NO. Mechanisms for this aerobic oxidation at different pH values are proposed.

Efficient Flash Memory Devices Based on Non-Conjugated Ferrocene-Containing Copolymers

A series of non-conjugated ferrocene-containing copolymers FcCP1–FcCP3 with a triphenylamine (TPA), benzothiazole (BT) or phenothiazine (PHZ) unit has been designed and synthesized via a facile radical polymerization protocol. The structural, photophysical, electrochemical and memory characteristics of these polymers were systematically studied. All the copolymers exhibited flash memory behaviour with a bistable conductive process, where FcCP1 showed a large ON/OFF current ratio of 103 to 104 with a low threshold voltage of −0.6 V. Such remarkable results suggest that non-conjugated ferrocene-containing copolymers are promising active materials for memory applications.