Tetra-EDOT substituted 3D electrochromic polymers with lower band gaps

A couple of novel electrochromic materials poly(2,3,4,5-tetrakis(2,3-hydrothieno[3,4-b]dixin-5-yl)-1-methyl-1H-pyrrole)(P(t-EDOT-mPy))and poly(5,5',5",5'"-(thiophene-2,3,4,5-tetrayl)tetrakis(2,3-dihydrothieno[3,4-b][1,4]dioxine))(P(t-EDOTTh))are electrodeposited via multi-position polymerization of their tetra-EDOT substituted monomers t-EDOT-mPy and t-EDOT-Th,respectively.Compared with the linear 2D structured poly(thiophene)(E_g=2.2 eV)and poly(2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophene)(E_g=1.7eV),P(t-EDOT-Th)(E_g=1.62eV)has the lowest band gap.Hence,we speculate that the band gaps of the two polymers,having 3D structures,are decreased in contrast to non-substituted polymers or bi-EDOT substituted polymers,thiophene and 1-methyl-1H-pyrrole.The results indicated that P(t-EDOT-Th)thin films are more stable and show higher transmittance amid two polymers,which may find their utilization in organic optoelectronics.     

Systematic synthesis, isolation, and photophysical properties of linear-shaped Re(I) oligomers and polymers with 2-20 units

Systematic synthesis routes have been developed for the linear-shaped rhenium(I) oligomers and polymers bridged with bidentate phosphorus ligands, [Re(N--N)(CO)3-PP-{Re(N--N)(CO)2-PP-}(n)Re(N--N)(CO)3](PF6)(n+2) (N--N = diimine, PP = bidentate phosphine, n = 0-18). These were isolated by size exclusion chromatography (SEC) and identified by (1)H NMR, IR, electrospray ionization Fourier transform mass spectrometry, analytical SEC, and elemental analysis. Crystal structures of [Re(bpy)(CO)3-Ph2PC[triple bond]CPPh2-Re(bpy)(CO)3](PF6)2, [Re(bpy)(CO)3-Ph2PC[triple bond]CPPh2-Re(bpy)(CO)2-Ph2PC[triple bond]CPPh2-Re(bpy)(CO)3](PF6)3 and [Re(bpy)(CO)3-Ph2PC2H4PPh2-{Re(bpy)(CO)2Ph2PC2H4PPh2-}(n)Re(bpy)(CO)3](PF6)(n+2) (bpy = 2,2'-bipyridine, n = 1, 2) were obtained, showing that they have interligand pi-pi interaction between the bpy ligand and the phenyl groups on the phosphorus ligand. All of the oligomers and polymers synthesized were emissive at room temperature in solution. For the dimers, broad emission was observed with a maximum at 523-545 nm, from the (3)MLCT excited-state of the tricarbonyl complex unit, [Re(N--N)(CO)3-PP-]. Emission from the longer oligomers and polymers with > or = 3 Re(I) units was observed at wavelengths 50-60 nm longer than those of the corresponding dimers. This fact and the emission decay results clearly show that energy transfer from the edge unit to the interior unit occurs with a rate constant of (0.9 x 10(8))-(2.5 x 10(8)) s(-1). The efficient energy transfer and the smaller exclusive volume of the longer Re(I) polymers indicated intermolecular aggregation for these polymers in an MeCN solution.     

Highly Defined ABC Triblock Cooligomers and Copolymers Prepared by ROMP Using an N‐Heterocyclic‐Carbene‐Substituted Ruthenium Benzylidene Initiator

The “3^rd generation Grubbs” initiator (H₂IMes)(3‐bromopyridine)₂(Cl)₂RuCHPh ( 1 ) accomplishes the synthesis of ABC triblock copolymers via living ring‐opening metathesis polymerisation (ROMP) of norbornene derivatives. Complete initiation and an outstanding tolerance of functional groups are provided, which is proven by a combined study by means of matrix‐assisted laser desorption/ionisation mass spectrometry, gel permeation chromatography and NMR spectroscopy on an ABC triblock cooligomer.

Gel permeation chromatograms of oligo A , oligo AB , and oligo ABC .     

Ring-opening metathesis polymerization of norbornene and norbornadiene by tungsten(II) and molybdenum(II) complexes

The reaction of norbornene (NBE) and norbornadiene (NBD) in the presence of seven-coordinate tungsten(II) and molybdenum(II) complexes of the [(CO)₄M(μ-Cl)₃M(SnCl₃)(CO)₃] and [MCl(M′Cl₃)(CO)₃(NCMe)₂] (M=W, Mo; M′=Sn, Ge) types leads to ring-opening metathesis polymerization (ROMP) and to the formation of high molecular weight polymers. The geometric structure of these polymers was determined by means of ¹H- and ¹³C-NMR spectroscopy. The monitoring of the reaction between cyclic olefins and the metal complex by means of ¹H-NMR spectroscopy allowed us to observe the coordination of NBD to metal atoms in the initiation step of the polymerization process. Compounds of the [MCl(SnCl₃)(CO)₃(η⁴-NBD)] type prepared directly from [(CO)₄M(μ-Cl)₃M(SnCl₃)(CO)₃] or [MCl(M′Cl₃)(CO)₃(NCMe)₂] (M=W, Mo) in the presence of an excess of NBD initiate the ROMP reaction immediately. The detection of the first-formed products in the reaction between the metal complex and cyclic olefins provides valuable information concerning the nature of the initiating species.     

Solvent‐Free Ring‐Opening Metathesis Polymerization of Norbornene over Silica‐Supported Tungsten–Oxo Perhydrocarbyl Catalysts

Ring opening metathesis polymerization (ROMP) of bicyclo[2.2.1]hept‐2‐ene (norbornene) is carried out over silica‐supported catalysts based on tungsten complexes bearing an oxo ligand ( 1 : [(SiO)W(O)(CH₂SiMe₃)₃, 2 : [(SiO)W(O)(CHCMe₂Ph)(dAdPO)], dAdPO  2,6 diadamantyl‐4‐methylphenoxide, 3 : [(SiO)₂W(O)(CH₂SiMe₃)₂]). The evaluation of the catalytic activities of the aforementioned materials in ROMP indicates that at low reaction time (0.5 min), the highest polymer yield is obtained with catalyst 2 . However, for longer reaction time (>2 min), complex 3 , a model of the industrial catalyst, exhibits a better monomer conversion. The polymers obtained are characterized. Moreover, these catalysts are shown to be rather preferentially selective to give the cis polynorbornene (>65%), characterized by high melting points (≈300 °C). The experimental values of the average molecular weight (M_n) of polynorbornenes are found to be close to the theoretical ones for the polymers prepared using catalyst 2 and higher for those originated from catalyst 3 .

     

Luminescent digold ethynyl thienothiophene and dithienothiophene complexes; their synthesis and structural characterisation

A series of protected and terminal dialkynes with extended pi-conjugation through the fused oligothienyl linker unit in the backbone, 2,5-bis(trimethylsilylethynyl)thieno[3,2-b]thiophene 1a, 5,5'-bis(trimethylsilylethynyl)dithieno[3,2-b:2',3'-d]thiophene 1b, 2,5-bis(ethynyl)thieno[3,2-b]thiophene 2a, 5,5'-bis(ethynyl)dithieno[3,2-b:2',3'-d]thiophene 2b, has been synthesized and characterised. The digold alkynyl complexes [(Ph3P)Au(C[triple bond]C)(C6H2S2)(C[triple bond]C)Au(PPh3)] 3a and [(Ph3P)Au(C[triple bond]C)(C8H2S3)(C[triple bond]C)Au(PPh3)] 3b have then been prepared by the reaction of two equivalents of Ph3PAuCl and a methanolic KOH solution of 1a and 1b, respectively. The complexes have been characterised spectroscopically. The crystal structures show that the gold centres adopt a linear two-coordinate geometry appropriate for Au(i) complexes. Within the crystals adjacent molecules are linked by Au...S intermolecular interactions in the range 3.48-3.89 A, but there are no short Au...Au contacts. The absence of Au...Au interactions in solution is confirmed by UV/visible absorption and emission spectroscopy, the spectra being dominated by ligand-centred pi-pi* interactions.     

Organic triplet excited states of gold(I) complexes with oligo(o- or m-phenyleneethynylene) ligands: conjunction of steady-state and time-resolved spectroscopic studies on exciton delocalization and emission pathways

A series of mononuclear and binuclear gold(I) complexes containing oligo(o- or m-phenyleneethynylene) (PE) ligands, namely [PhC≡C(C(6)H(4)-1,2-C≡C)(n-1)Au(PCy(3))] (n = 2-4, 4a-c), [μ-{C≡C-(1,2-C(6)H(4)C≡C)(n)}{Au(PCy(3))}(2)] (n = 1-6, 8, 5a-g), [PhC≡C(C(6)H(4)-1,3-C≡C)(n-1)Au(PCy(3))] (n = 2-4, 6a-c), and [μ-{C≡C-(1,3-C(6)H(4)C≡C)(n)}{Au(PCy(3))}(2)] (n = 1, 2, 7a,b), were synthesized and structurally characterized. Extensive spectroscopic measurements have been performed by applying combined methods of femtosecond transient absorption (fs-TA), fs time-resolved fluorescence (fs-TRF), and nanosecond time-resolved emission (ns-TRE) coupled with steady-state absorption and emission spectroscopy at both ambient and low (77 K) temperatures to directly probe the temporal evolution of the excited states and to determine the dynamics and spectral signatures for the involved singlet (S(1)) and triplet (T(1)) excited states. The results reveal that S(1) and T(1) both feature ligand-centered electronic transitions with ππ* character associated with the phenyl and acetylene moieties. The (3)ππ* emission of the PE ligands is switched on by the attachment of [Au(PCy(3))](+) fragment(s) due to the heavy-atom effect. T(1)((3)ππ*) was found to form with nearly unity efficiency through intersystem crossing (ISC) from S(1)((1)ππ*). The ISC time constants were determined to be ～50, 35, and 40 ps for 4b and 6a,b, respectively. Dual emission composed of fluorescence from S(1) and phosphorescence from T(1) were observed for most of the complexes except 5a and 7a, where only phosphorescence was found. The fluorescence at ambient temperature is accounted for by both the short-lived prompt fluorescence (PF) and long-lived delayed fluorescence (DF, lifetime on microsecond time scale). Explicit evidence was presented for a triplet-triplet annihilation mechanism for the generation of DF. Ligand length and substitution-dependent dynamics of T(1) are the key factors governing the dual emission character of the complexes. By extrapolation from the plot of emission energy against the PE chain length of the [Au(PCy(3))](+) complexes with oligo(o-PE) or oligo(m-PE) ligands, the triplet emission energies were estimated to be ～530 and ～470 nm for poly(o-PE) and poly(m-PE), respectively. Additionally, we assign the unusual red shifts of 983 cm(-1) from [PhC≡CAu(PCy(3))] (1) to [μ-{1,3-(C≡C)(2)C(6)H(4)}{Au(PCy(3))}(2)] (7a) and 462 cm(-1) from 7a to [μ(3)-{1,3,5-(C≡C)(3)C(6)H(3)}{Au(PCy(3))}(3)] (8) in the phosphorescence energies to excitonic coupling interactions between the C≡CAu(PCy(3)) arms in the triplet excited states. These complexes, together with those previously reported [Au(PCy(3))](+) complexes containing oligo(p-PE) ligands ( J. Am. Chem. Soc. 2002 , 124 , 14696 - 14706 ), form a collection of oligo(phenyleneethynylene) complexes exhibiting organic triplet emission in solution under ambient conditions. The remarkable feature of these complexes in exhibiting TTA prompted DF in conjunction with high formation efficiency of T(1)((3)ππ*) affords an opportunity for emission spectra to cover a wide range of wavelengths. This may have implication in the development of PE-based molecular materials for future optical applications.     

Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes: Mechanistic evaluation of an electrophilic olefin metathesis system

The reaction of [Re(H)(NO)2(PR3)2] complexes (1 a: R = PCy3; 1 b: R = PiPr3) with [H(OEt2)2][BAr(F)4] ([BAr(F)4] = tetrakis{3,5-bis(trifluoromethyl)phenyl}borate) in benzene at room temperature gave the corresponding cations [Re(NO)2(PR3)2][BAr(F)4] (2 a and 2 b). The addition of phenyldiazomethane to benzene solutions of 2 a and 2 b afforded the moderately stable cationic rhenium(I)-benzylidene-dinitrosyl-bis(trialkyl)phosphine complexes 3 a and 3 b as [BAr(F)4]- salts in good yields. The complexes 2 a and 2 b catalyze the ring-opening metathesis polymerization (ROMP) of highly strained nonfunctionalized cyclic olefins to give polymers with relatively high polydispersity indices, high molecular weights and over 80 % Z configuration of the double bonds in the chain backbone. However, these complexes do not show metathesis activity with acyclic olefins. The benzylidene derivatives 3 a and 3 b are almost inactive in ROMP catalysis with norbornene and in olefin metathesis. NMR experiments gave the first hints of the initial formation of carbene complexes from [Re(NO)2(PR3)2][BAr(F)4] (2 a and 2 b) and norbornene. In a detailed mechanistic study ESI-MS/MS measurements provided further evidence that the carbene formation is initiated by a unique reaction sequence where the cleavage of the strained olefinic bond starts with phosphine migration forming a cyclic ylide-carbene complex, capable of undergoing metathesis with alternating rhenacyclobutane formation and cycloreversion reactions ("ylide" route). However, even at an early stage the ROMP propagation route is expected to merge into an "iminate" route by attack by the ylide function on one of the N(NO) atoms followed by phosphine oxide elimination. The formation of phosphine oxide was confirmed by NMR spectroscopy. The proposed mechanism is supported further by detailed DFT calculations.     

Theoretical Study on Electronic and Charge Transfer Properties of Oligo[8]thiophene and Its Circular,Hooped, and Helical Derivatives

The novel linear, circular, hooped, and helical molecules based on oligo[8]thio- phene were theoretically studied for the applications of charge transfer devices. To investigate the influence of topology for oligo[8]thiophene derivatives, the geometry structures, frontier molecular orbital （FMO） energies, charge transport properties, and stability property were predicted by density functional theory methods. The calculated results reported herein show that the oligo[8]thiophene derivative with linear structure has smaller energy gap, and fused oligo[8]thiophene derivative with circular structure has the smallest reorganization energy among the designed molecules. We have also studied the stability properties of the designed molecules, and oligo[8]thiophene derivatives are more stable tharJ the fused oligo[8]thiophene derivatives.     

Synthesis and charge/discharge properties of polyacetylenes carrying 2,2,6,6-tetramethyl-1-piperidinoxy radicals

The 2,2,6,6-tetramethyl-1-piperidinoxy (TEMPO)-containing acetylenic monomers HC[triple bond]CC(6)H(3)-p,m-(CONH-4-TEMPO)(2) (1), HC[triple bond]CC(6)H(3)-p,m-(COO-4-TEMPO)(2) (2), (S,S,S,S)-HC[triple bond]CC(6)H(3)-p,m-[CO-NHCH{COO-(4-TEMPO)}CH(2)COO-(4-TEMPO)](2) (3), (S,S)-HC[triple bond]CC(6)H(4)CO-NHCH{COO-(4-TEMPO)}CH(2)COO-(4-TEMPO) (4), HC[triple bond]CC(6)H(4)-p-OCO-4-TEMPO (5), HC[triple bond]CCH(2)C(CH(3))(CH(2)OCO-4-TEMPO)(2) (6), HC[triple bond]CCH(2)NHCO-4-TEMPO (7), and HC[triple bond]CCH(2)OCO-4-TEMPO (8) were polymerized to afford novel polymers containing the TEMPO radical at high densities. Monomers 1, 3-6, and 8 provided polymers with average molecular weights of 10 000-136 500 in 62-99 % yield in the presence of a rhodium catalyst, whereas monomers 2 and 7 gave insoluble polymers in 100 % yield. The formed polymers were thermally stable up to approximately 274 degrees C according to thermogravimetric analysis (TGA). All the TEMPO-containing polymers demonstrated reversible charge/discharge processes, whose discharge capacities were 21.3-108 A h kg(-1). In particular, the capacity of poly(1)-, poly(4)-, and poly(5)-based cells reached 108, 96.3, and 89.3 A h kg(-1), respectively, which practically coincided with their theoretical values.     

Group 4 dimethylsilylenebisamido complexes bearing the 6-[2-(diethylboryl)phenyl]pyrid-2-yl motif: synthesis and use in tandem ring-opening metathesis/vinyl-insertion copolymerization of cyclic olefins with ethylene

Two novel Zr(IV)- and Hf(IV)-based bisamido complexes bearing the 6-[2-(diethylboryl)phenyl]pyrid-2-yl motif, that is, [ZrCl(2){Me(2)Si(DbppN)(2)}(thf)] (9) and [HfCl(2){Me(2)Si(DbppN)(2)}(thf)(2)] (10) (DbppN=6-[2-(diethylboryl)phenyl]pyridine-2-amido) have been prepared. Their reactivities have been compared with that of a model precatalyst that does not bear the aminoborane motif. Upon activation with methylalumoxane, precatalysts 9 and 10 are active in the homopolymerization of ethylene (E) yielding high-density polyethylene (HDPE). In the copolymerization of E with cyclopentene (CPE), for example by the action of 9, the presence of CPE resulted in a dramatic increase in the polymerization activity of E, while CPE incorporation remained close to or at zero. In the vinyl-insertion copolymerization of norborn-2-ene (NBE) with E by the action of 9, statistical cyclic olefin copolymers of these two monomers were obtained. At higher NBE concentrations, however, 9 gave rise to reversible ring-opening metathesis (ROMP)/vinyl-insertion polymerization (VIP) of NBE with E, resulting in the formation of multi-block copolymers of the general formula poly(NBE)(ROMP)-co-poly(NBE)(VIP)-co-poly(E). This particular feature of precatalyst 9, that is, the ability to induce a reversible α-H elimination/α-H addition reaction, is attributed to the unique role of the 6-[2-(diethylboryl)phenyl]pyrid-2-yl ligand. Accordingly, a model precatalyst lacking this ligand does not have the ability to induce α-H elimination/α-H addition reactions. The different (11)B NMR shifts of various diethylborylphenylpyrid-2-ylamines and -amides permit a ranking of the strengths of the B-N bonds in these compounds. This strength of the B-N bond is correlated with the propensity of 9/MAO to produce poly(NBE)(ROMP)-co-poly(NBE)(VIP)-co-poly(E) at different temperatures.     

New coordination polymers with extended arm cyclotriguaiacyclene ligands: 1D chains, and interpenetrating or polycatenating 2D (4(2).6(2))(4.6(2))2 networks

A series of new 1D chain and 2D coordination polymers with cyclotriguaiacylene-type ligands are reported. A zig-zag 1D coordination chain is found in complex [Cd(2)(4ph4py)(NO(3))(3)(H(2)O)(2)(DMA)(2)]·(NO(3))·(DMA)(4), where 4ph4py = tris[4-(4-pyridyl)benzoyl]-cyclotriguaiacylene and DMA = dimethylacetamide, while complex [Zn(4ph4py)(2)(CF(3)COO)(H(2)O)]·(CF(3)COO)(NMP)(7), where NMP = N-methylpyrrolidone, has a doubly bridged coordination chain structure. Complexes [M(3ph3py)(NO(3))(2)]·(NMP)(4) where M = Co or Zn, 3ph3py = tris[3-(3-pyridyl)benzoyl]cyclotriguaiacylene, are isostructural and feature 1D ladder coordination chains. Complexes [Cd(2)(4ph4py)(2)(NO(3))(4)(NMP)]·(NMP)(9)(H(2)O)(4) and [Co(4ph4py)(H(2)O)(2)]·(NO(3))(2)·(DMF)(2), where DMF = dimethylformamide, both have (3,4)-connected 2D coordination polymers with a rare (4(2).6(2))(4.6(2))(2) topology. A 2D coordination polymer with this topology is also found in complex [Co(2)(3ph4py)(2)(NO(3))(H(2)O)(5)]·(NO(3))(3)·(DMF)(9) where 3ph4py = tris[3-(4-pyridyl)benzoyl]cyclotriguaiacylene. All 2D coordination polymer complexes are interpenetrating or polycatenating. [Co(2)(3ph4py)(2)(NO(3))(H(2)O)(5)](3+)polymers form a 2D→3D polycatenation showing self-complementary "hand-shake" interactions between the host-type ligands.     

Inhibition of cell adhesion to fibronectin by oligopeptide-substituted polynorbornenes.

Polynorbornenes substituted with two different peptide sequences from the RGD-containing integrin cell-binding domain of fibronectin are potent inhibitors of human foreskin fibroblast cell adhesion to fibronectin-coated surfaces. Ring-opening metathesis polymerization (ROMP) using Ru==CHPh(Cl)(2)(PCy(3))(DHIMes) (1) as an initiator produced polymers substituted with GRGDS and PHSRN peptide sequences. The inhibitory activity was quantified for these polymers and compared to the free peptides and GRGES-containing controls. A homopolymer substituted with GRGDS peptides was significantly more active than the free GRGDS peptide (IC(50) of 0.18 +/- 0.03 and 1.33 +/- 0.20 mM respectively), and the copolymer containing both GRGDS and PHSRN is the most potent inhibitor (IC(50) of 0.04 +/- 0.01 mM). These results demonstrate that significant enhancements of observed biological activity can be obtained from polymeric materials containing more than one type of multivalent ligand and that ROMP is a useful method to synthesize such well-defined copolymers.     

离子液体负载钌络合物的合成及其催化环烯烃开环易位聚合

设计合成了含离子液体的吡啶配体1,2-二甲基-3-乙氧基吡啶六氟磷酸盐咪唑离子液体,在丙酮∶石油醚=3∶1的混合溶剂制备了含咪唑的离子液体.该离子液体可以做配体与Grubbs第二代催化剂反应,制备离子液体负载的钌催化剂,利用(1H,13C,31P)-NMR、元素分析等方法对合成的化合物和催化剂进行表征,催化剂中与钌连接的苯亚甲基上氢(RuCH—Ph)的振动峰由原来第二代催化剂的δ=19.2移至δ=16.27,在δ=-143.3处只出现PF6-中磷的信号峰,PCy3的信号消失,表明PCy3已经被置换完全,得到了新的催化剂.通过ICP测定含吡啶配体的离子液体负载的催化剂在混合物中的含量为14wt%.该催化剂在丙酮、甲醇、咪唑类离子液体等极性溶剂中易于溶解,解决了Grubbs催化剂在离子液体中不溶解的问题,实现了在纯离子液体中均相ROMP反应.考察了催化剂对不同极性单体在离子液体[BMIm]BF4中的开环易位聚合反应,非极性的环辛烯、含有中等极性取代基的5-羟基环辛烯单体以及含强极性取代基的5-腈基-2-降冰片烯单体的转化率分别为96%、73%和51.7%.利用凝胶渗透色谱(GPC)测定了聚合物的分子量及分子量分布.     

Alkylthio‐Substituted Polythiophene: Absorption and Photovoltaic Properties

Two polythiophene derivatives with electron‐donating alkylthio side chains, poly[(3‐hexylthio)thiophene] (P3HST) and poly[(3‐hexylthio)thiophene‐alt‐thiophene] (P3HST‐co‐Th) have been synthesized and characterized. Both P3HST and P3HST‐co‐Th show broader absorption peaks than poly(3‐hexylthiophene). Meanwhile, the alkylthio side chains decrease the HOMO energy level of the polymers, which benefits the higher open circuit voltage of the polymer solar cells (PSCs) based on the polymer as donor. PSCs have been fabricated with the polymers as donor and [6,6]‐phenyl C61 butyric acid methyl ester as acceptor (1: 1, w/w). The devices based on P3HST and P3HST‐co‐Th show an open circuit voltage of 0.63 V, and a power conversion efficiency of 0.34% and 0.5%, respectively, under the illumination of AM1.5, 80 mW · cm⁻².

     

Preparation and solid-state characterization of mixed-ligand coordination/organometallic oligomers and polymers of copper(I) and silver(I) using diphosphine and mono- and diisocyanide ligands

The dimers [Cu(2)(dppm)(2)(CN-t-Bu)(3)](BF(4))(2) and [Ag(2)(dppm)(2)(CN-t-Bu)(2)](X)(2) (X(-) = BF(4)(-), ClO(4)(-)) and the coordination polymers [[M(diphos)(CN-t-Bu)(2)]BF(4)](n) (M = Cu, Ag; diphos = bis(diphenylphosphino)butane (dppb), bis(diphenylphosphino)pentane (dpppen), bis(diphenylphosphino)hexane (dpph)), [[Ag(2)(dppb)(3)(CN-t-Bu)(2)](BF(4))(2)](n), and [[Ag(dpppen)(CN-t-Bu)]BF(4)](n) have been synthesized and fully characterized as model materials for the mixed bridging ligand polymers which exhibit the general formula [[M(diphos)(dmb)]BF(4)](n) (M = Cu, Ag; dmb = 1,8-diisocyano-p-menthane) and [[Ag(dppm)(dmb)]ClO(4)](n). The identity of four polymers ([[Ag(dppb)(CN-t-Bu)(x)]BF(4)](n) (x = 1, 2), [[Ag(2)(dppb)(3)(CN-t-Bu)(2)](BF(4))(2)](n), [[Ag(dppm)(dmb)]ClO(4)](n)) and the two dimers has been confirmed by X-ray crystallography. The structure of [[Ag(dppm)(dmb)]ClO(4)](n) exhibits an unprecedented 1-D chain of the type "[Ag(dmb)(2)Ag(dppm)(2)(2+)](n)", where d(Ag(.)Ag) values between tetrahedral Ag atoms are 4.028(1) and 9.609(1) A for the dppm and dmb bridged units, respectively. The [[Ag(dppb)(CN-t-Bu)(x)]BF(4)](n) polymers (x = 1, 2) form zigzag chains in which the Ag atoms are tri- and tetracoordinated, respectively. The [[Ag(2)(dppb)(3)(CN-t-Bu)(2)](BF(4))(2)](n) polymer, which is produced from the rearrangement of [[Ag(dppb)(CN-t-Bu)(2)]BF(4)](n), forms a 2-D structure described as a "honeycomb" pattern, where large [Ag(dppb)(+)](6) macrocycles each hosting two counterions and two acetonitrile guest molecules are observed. Properties such as glass transition temperature, morphology, thermal decomposition, and luminescence in the solid state at 293 K are reported. The luminescence bands exhibit maxima between 475 and 500 nm with emission lifetimes ranging between 6 and 55 micros. These emissions are assigned to a metal-to-ligand charge transfer (MLCT) of the type M(I) --> pi(NC)/pi(PPh(2)).     

Synthesis, characterization and biocompatibility studies of oligosiloxane modified polythiophenes

This paper describes the preparation and characterization of homopolymers of 3-oligo(dimethylsiloxane)thiophene macromonomers, V-VIII, and copolymers with 3-methylthiophene. The thiophene macromonomers were prepared by hydrosilylation reaction between ω-(Si-H)-oligo(dimethylsiloxane), I-IV, and 3-propenylthiophene using a platinum-divinyltetramethyldisiloxane complex as the catalyst. The products were characterized by ¹H, ¹³C, ²⁹Si NMR and IR spectroscopy; DSC (differential scanning calorimetry) and GPC studies. Two distinct glass transition temperatures are observed for poly[VIII], a T_g at −79 °C corresponds to the soft oligo(dimethylsiloxane) phase and the T_g at 190 °C corresponds to the hard thiophene backbone. Homopolymers of V and VI, and copolymers may be doped with I₂ to generate electronic conductive material, a copolymer of poly[V]-co-poly[3-methylthiophene] (50/50, w/w) has an electronic conductivity value of 5 × 10⁻⁵ S/cm at 25 °C. The polymers are tractable and may be molded into thin films; a number of the polymers are soluble in organic solvents. Polythiophene modified with oligosilioxanes are biocompatibile; the polymers minimally interfere with the growth of HeLa cells.     

The pH-induced emission switching and interesting DNA-binding properties of a novel dinuclear ruthenium(II) complex

A novel dinuclear Ru(II) complex, [(bpy)(2)Ru(ebipcH(2))Ru(bpy)(2)](ClO(4))(4), where bpy = 2,2'-bipyridine and ebipcH(2) = N-ethyl-4,7-bis([1,10]-phenanthroline[5,6-f]imidazol-2-yl)carbazole, has been newly synthesized. The pH effects on UV-vis absorption and emission spectra of the complex are studied, and ground- and excited-state ionization constants of the complex are derived. The binding of the complex to calf thymus (ct) DNA is investigated with absorption and luminescence titrations, steady-state emission quenching, and viscosity measurements. The complex acts as a pH-induced "on-off" emission switch between pH 8.0 and pH 10.0 with a maximum on-off ratio of approximately 100 which is favorably compared with the other imidazole-containing Ru(II) complex congeners, and a strong ct-DNA intercalator with an intrinsic binding constant of 1.31(+/-0.08) x 10(6) M(-)(1) in buffered 50 mM NaCl.     

Synthesis,Crystal Structures,and Magnetic Properties of Two Manganese(II)/Cobalt(II) Coordination Polymers Constructed by Nitrogenous Carboxylic Acid

Russian Journal of General Chemistry - Two new coordination polymers, {[Mn2(L)(H2O)2]·H2O}n (1) and {[Co2(L)(H2O)2]·H2O}n (2) (H4L = 2-(2,4,6-tricarboxylphenyl)-6-carbxoylbenzimi-dazole),...     

Ring-opening metathesis polymerization of cis-5-norbornene-endo-2,3-dicarboxylic anhydride derivatives using the grubbs third generation catalyst

A series of cis-5-norbornene-endo-2,3-dicarboxylic anhydride(NDCA,M1) derivatives(M2-M4) with different types of nonpolar substituted groups were synthesized and characterized by ~1H/~(13)C-NMR and mass spectrometry(MS). Ringopening metathesis polymerization(ROMP) of these monomers using the Grubbs third generation catalyst(G3) generated high molecular weight polymers with much improved solubility compared with the NDCA's homopolymer. It was found that the solubility of these polymers increased with increased substituent's steric hindrance. The living polymerization of NDCA derivative containing the bulkiest substituent(M4) catalyzed by G3 in tetrahydrofuran was confirmed by the kinetic studies with low polydispersity indices(PDI)( 1.30). By using sequential ROMP, well-defined diblock copolymers containing anhydride groups were synthesized.