Synthesis of poly(1‐chloro‐2‐arylacetylene)s with high cis‐content and examination of their absorption/emission properties

A series of 1‐chloro‐2‐arylacetylenes [Cl‐C?C‐Ar, Ar = C₆H₅ ( 1 ), C₆H₄‐p‐i Pr ( 2 ), C₆H₄‐p‐Oi Pr ( 3 ), C₆H₄‐p‐NHC(O)Ot Bu ( 4 ), and C₆H₄‐o‐i Pr ( 5 )] were polymerized using (tBu₃P)PdMeCl/silver trifluoromethanesulfonate (AgOTf) and MoCl₅/SnBu₄ catalysts. The corresponding polymers [poly( 1 )–poly( 5 )] with weight‐average molecular weights of 6,500–690,000 were obtained in 10–91% yields. THF‐insoluble parts, presumably high‐molecular weight polymers, were formed together with THF‐soluble polymers by the Pd‐catalyzed polymerization. The Pd catalyst polymerized nonpolar monomers 1 and 2 to give the polymers in yields lower than the Mo catalyst, while the Pd catalyst polymerized polar monomers 3 and 4 to give the corresponding polymers in higher yields. The ¹H NMR and UV–vis absorption spectra of the polymers indicated that the cis‐contents of the Pd‐based polymers were higher than those of the Mo‐based polymers, and the conjugation length of the Pd‐based polymers was shorter than that of the Mo‐based polymers. Pd‐based poly( 5 ) emitted fluorescence most strongly among poly( 1 )–poly( 5 ). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 382–388     

Supramolecular Polymers Self‐Assembled from trans‐Bis(pyridine) Dichloropalladium(II) and Platinum(II) Complexes

Two structurally similar trans‐bis(pyridine) dichloropalladium(II)‐ and platinum(II)‐type complexes were synthesized and characterized. They both self‐assemble in n‐hexane to form viscous fluids at lower concentrations, but form metallogels at sufficient concentrations. The viscous solutions were studied by capillary viscosity measurements and UV/Vis absorption spectra monitored during the disassembly process indicated that a metallophilic interaction was involved in the supramolecular polymerization process. For the two supramolecular assemblies, uncommon continuous porous networks were observed by using SEM and TEM revealed that they were built from nanofibers that fused and crosslinked with the increase of concentration. The xerogels of the palladium and platinum complexes were carefully studied by using synchrotron radiation WAXD and EXAFS. The WAXD data show close stacking distances driven by π–π and metal–metal interactions and an evident dimer structure for the platinum complex was found. The coordination bond lengths were extracted from fitting of the EXAFS data. Moreover, close Pt^II–Pt^II (Pd^II–Pd^II) and Pt?Cl (Pd?Cl) interactions proposed from DFT calculations in the reported oligo(phenylene ethynylene) (OPE)‐based palladium(II) pyridyl supramolecular polymers were also confirmed by using EXAFS. The Pt^II–Pt^II interaction is more feasible for supramolecular interaction than the Pd^II–Pd^II interaction in our simple case.     

Palladium(II)‐catalyzed cyclization of W‐(2′,4′‐dienyl)‐2‐alkynamides to α‐alkylidene‐γ‐butyrolactams

In the presence of CuCl₂, N‐(2′, 4′‐dienyl)‐2‐alkynamides can be converted to α‐alkylidene‐σ‐butyrolactams under the catalysis of palladium(II). In this reaction, CuCl₂ is used to oxidize Pd(0) to regenerate Pd(II), or the carbon‐palladium bond is quenched by the oxidative cleavage reaction of CuCl₂.     

A triangular palladium(II) supramolecular coordination complex based on 1,4‐bis(1H‐imidazol‐1‐yl)benzene and (2,2′‐bipyridyl)palladium(II) nitrate: synthesis and crystal structure

The self‐assembly of ditopic bis(1H‐imidazol‐1‐yl)benzene ligands ( L ^H) and the complex (2,2′‐bipyridyl‐κ²N,N′)bis(nitrato‐κO)palladium(II) affords the supramolecular coordination complex tris[μ‐bis(1H‐imidazol‐1‐yl)benzene‐κ²N³:N^3′]‐triangulo‐tris[(2,2′‐bipyridyl‐κ²N,N′)palladium(II)] hexakis(hexafluoridophosphate) acetonitrile heptasolvate, [Pd₃(C₁₀H₈N₂)₃(C₁₂H₁₀N₄)₃](PF₆)₆·7CH₃CN, 2 . The structure of 2 was characterized in acetonitrile‐d₃ by ¹H/¹³C NMR spectroscopy and a DOSY experiment. The trimeric nature of supramolecular coordination complex 2 in solution was ascertained by cold spray ionization mass spectrometry (CSI–MS) and confirmed in the solid state by X‐ray structure analysis. The asymmetric unit of 2 comprises the trimetallic Pd complex, six PF₆^? counter‐ions and seven acetonitrile solvent molecules. Moreover, there is one cavity within the unit cell which could contain diethyl ether solvent molecules, as suggested by the crystallization process. The packing is stabilized by weak inter‐ and intramolecular C—H…N and C—H…F interactions. Interestingly, the crystal structure displays two distinct conformations for the L ^H ligand (i.e. syn and anti), with an all‐syn‐[Pd] coordination mode. This result is in contrast to the solution behaviour, where multiple structures with syn/anti‐ L ^H and syn/anti‐[Pd] are a priori possible and expected to be in rapid equilibrium.     

Homo‐ and copolymerization of norbornene and 5‐norbornene‐2‐yl acetate with bis‐(β‐ketonaphthylamino)palladium(II)/B(C6F5)3 catalytic system

The polymerization of norbornene with bis(β‐ketonaphthylamino) palladium(II), Pd{CH₃C(O)CHC[N(naphthyl)]CH₃}₂, in combination with tris(pentafluorophenyl)borane (B(C₆F₅)₃), was investigated by varying the B:Pd(II) molar ratio, monomer concentration, reaction temperature, and time. The catalytic activity was found to reach 2.8 × 10⁴ gPolymer/(molPd^?h) and the obtained polynorbornene (PNBE) was confirmed to be vinyl addition polymer and showed good thermo‐stability (T_dec > 350°C), but exhibited poor solubility in organic solvents due to the relative higher stereo regularity. Pd{CH₃C(O)CHC[N(naphthyl)]CH₃}₂/B(C₆F₅)₃ system is also an active catalyst for copolymerization of norbornene and 5‐norbornene‐2‐yl acetate (NBE‐OCOCH₃) in toluene with moderate yields (in 9.2–36.5% yields) and produces the addition‐type copolymer with relatively high molecular weights (0.96 × 10⁴–2.13 × 10⁴ g/mol). The incorporation of functional group in the copolymer can be controlled up to 0.9–23.5 mol% by varying the NBE‐OCOCH₃ monomer feed ratios from 10 to 90%. The copolymers are proved to be noncrystalline and show good solubility in common organic solvents and excellent thermal stability up to 350°C. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis and Cytotoxicity of 2‐(2′‐Pyridyl)benzimidazole Complexes of Palladium(II) and Platinum(II)

Compounds of type [MX₂(Hpben)] [M = Pd (X = Cl), Pt (X = Cl, I); Hpben = 2‐(2′‐pyridyl)benzimidazole] were prepared and characterized, and the structures of the Pt derivatives were determined by X‐ray crystallography. The crystals of [PtI₂(Hpben)] consist of discrete units in which the Pt atom is coordinated to two iodine atoms and to pyridine and imidazole N atoms in a distorted square planar arrangement. The structure of the chloro derivative is similar, except that the [PtCl₂(Hpben)] monomers are hydrogen‐bonded in zig‐zag chains. In assays of the interactions of the Pd and Pt chloro compounds with DNA, and of their in vitro cytotoxic activity against human cervical carcinoma cells (HeLa‐229), human ovarian carcinoma cells (A2780) and a cisplatin‐resistant mutant A2780 line (A2780cis), the only activity observed was modest cytotoxicity of the Pd derivative for A2780.     

(4,4′‐Bipyridine)mercury(II) Coordination Polymers,Syntheses, and Structures

Mercury(II) complexes with 4,4′‐bipyridine (4,4′‐bipy) ligand were synthesized and characterized by elemental analysis, and IR, ¹H‐ and ¹³C‐NMR spectroscopy. The structures of the complexes [Hg₃(4,4′‐bipy)₂(CH₃COO)₂(SCN)₄]_n ( 1 ), [Hg₅(4,4′‐bipy)₅(SCN)₁₀]_n ( 2 ), [Hg₂(4,4′‐bipy)₂(CH₃COO)₂]_n(ClO₄)_2n ( 3 ), and [Hg(4,4′‐bipy)I₂]_n ( 4 ) were determined by X‐ray crystallography. The single‐crystal X‐ray data show that 2 and 4 are one‐dimensional zigzag polymers with four‐coordinate Hg‐atoms, whereas 1 is a one‐dimensional helical chain with two four‐coordinate and one six‐coordinate Hg‐atom. Complex 3 is a two‐dimensional polymer with a five‐coordinate Hg‐atom. These results show the capacity of the Hg‐ion to act as a soft acid that is capable to form compounds with coordination numbers four, five, and six and consequently to produce different forms of coordination polymers, containing one‐ and two‐dimensional networks.     

Formal Gold‐to‐Gold Transmetalation of an Alkynyl Group Mediated by Palladium: A Bisalkynyl Gold Complex as a Ligand to Palladium

The reaction of [Au(C?C?n‐Bu)]_n with [Pd(η³‐allyl)Cl(PPh₃)] results in a ligand and alkynyl rearrangement, and leads to the heterometallic complex [Pd(η³‐allyl){Au(C?C?n‐Bu)₂}]₂ ( 3 ) with an unprecedented bridging bisalkynyl–gold ligand coordinated to palladium. This is a formal gold‐to‐gold transmetalation that occurs through reversible alkynyl transmetalations between gold and palladium.     

Copper(II) bromide and copper(II) acetate complexes of 4,4′‐(p‐phenylene)bipyridazine

4,4′‐(p‐Phenylene)bipyridazine, C₁₄H₁₀N₄, (I), and the coordination compounds catena‐poly[[dibromidocopper(II)]‐μ‐4,4′‐(p‐phenylene)bipyridazine‐κ²N²:N^2′], [CuBr₂(C₁₄H₁₀N₄)]_n, (II), and catena‐poly[[[tetrakis(μ‐acetato‐κ²O:O′)dicopper(II)]‐μ‐4,4′‐(p‐phenylene)bipyridazine‐κ²N¹:N^1′] chloroform disolvate], {[Cu₂(C₂H₃O₂)₄(C₁₄H₁₀N₄)]·2CHCl₃}_n, (III), contain a new extended bitopic ligand. The combination of the p‐phenylene spacer and the electron‐deficient pyridazine rings precludes C—H...π interactions between the lengthy aromatic molecules, which could be suited for the synthesis of open‐framework coordination polymers. In (I), the molecules are situated across a center of inversion and display a set of very weak intermolecular C—H...N hydrogen bonds [3.399 (3) and 3.608 (2) Å]. In (II) and (III), the ligand molecules are situated across a center of inversion and act as N²,N^2′‐bidentate [in (II)] and N¹,N^1′‐bidentate [in (III)] long‐distance bridges between the metal ions, leading to the formation of coordination chains [Cu—N = 2.005 (3) Å in (II) and 2.199 (2) Å in (III)]. In (II), the copper ion lies on a center of inversion and adopts CuN₂Br₄ (4+2)‐coordination involving two long axial Cu—Br bonds [3.2421 (4) Å]. In (III), the copper ion has a tetragonal pyramidal CuO₄N environment. The uncoordinated pyridazine N atom and two acetate O atoms provide a multiple acceptor site for accommodation of a chloroform solvent molecule by trifurcated hydrogen bonding [C—H...O(N) = 3.298 (5)–3.541 (4) Å].     

N‐Benzoyl‐N′,N′‐dibutylselenourea and its palladium(II) complex

The crystal and molecular structures of N‐benzoyl‐N′,N′‐dibutylselenourea (HL), C₁₆H₂₄N₂OSe, and the corresponding complex bis(N‐benzoyl‐N′,N′‐dibutylselenoureato‐κ²Se,O)palladium(II), [Pd(C₁₆H₂₃N₂OSe)₂], are reported. The selenourea molecule is characterized by intermolecular hydrogen bonds between the selenoamidic H atom and the Se atom of a neighbouring molecule forming a dimer, presumably as a consequence of resonance‐assisted hydrogen bonding or π‐bonding co‐operativity. A second dimeric hydrogen bond is also described. In the palladium complex, the typical square‐planar coordination characteristic of such ligands results in a cis‐[Pd(L‐Se,O)₂] complex.     

One‐dimensional CuII coordination polymers containing C2h‐symmetric 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate linkers

Two new one‐dimensional Cu^II coordination polymers (CPs) containing the C_2h‐symmetric terphenyl‐based dicarboxylate linker 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate (3,3′‐TPDC), namely catena‐poly[[bis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ⁴O,O′:O′′:O′′′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂]·H₂O}_n, (I), and catena‐poly[[aquabis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ²O³:O^3′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂(H₂O)]·H₂O}_n, (II), were both obtained from two different methods of preparation: one reaction was performed in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a potential pillar ligand and the other was carried out in the absence of the DABCO pillar. Both reactions afforded crystals of different colours, i.e. violet plates for (I) and blue needles for (II), both of which were analysed by X‐ray crystallography. The 3,3′‐TPDC bridging ligands coordinate the Cu^II ions in asymmetric chelating modes in (I) and in monodenate binding modes in (II), forming one‐dimensional chains in each case. Both coordination polymers contain two coordinated dimethylamine ligands in mutually trans positions, and there is an additional aqua ligand in (II). The solvent water molecules are involved in hydrogen bonds between the one‐dimensional coordination polymer chains, forming a two‐dimensional network in (I) and a three‐dimensional network in (II).     

Synthesis of regioregular poly(3‐octylthiophene)s via Suzuki polycondensation and end‐group analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Regioregular poly(3‐octylthiophene)s were synthesized through a palladium‐catalyzed Suzuki polycondensation of 2‐(5‐iodo‐4‐octyl‐2‐thienyl)‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolane. The effects of the palladium catalyst {tetrakis(triphenylphosphine)palladium(0) [Pd(PPh₃)₄], palladium(II) acetate [Pd(OAc)₂], [1, 1′‐bis(diphenylphosphino)ferrocene]dichloropalladium(II) [Pd(dppf)Cl₂], tris(dibenzylideneacetone)dipalladium(0), or bis(triphenylphosphine)palladium(II) dichloride [Pd(PPh₃)₂Cl₂]} and the reaction conditions (bases and solvents) were investigated. NMR spectroscopy revealed that poly(3‐octylthiophene)s prepared via this route were essentially regioregular. According to size exclusion chromatography, the highest molecular weights were obtained with in situ generated Pd(PPh₃)₄ and tetrakis(tri‐o‐tolylphosphine]palladium(0) {Pd[P(o‐Tol)₃]₄} catalysts or more reactive, phosphine‐free Pd(OAc)₂. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry was used to analyze end groups and allowed the determination of some mechanistic aspects of the Suzuki polycondensation. The polymers were commonly terminated with hydrogen or iodine as a result of deboronation and some deiodination. Pd(PPh₃)₄, Pd(PPh₃)₂Cl₂, and Pd[P(o‐Tol)₃]₄ induced aryl–aryl exchange reactions with the palladium center and resulted in some chains having phenyl‐ and o‐tolyl‐capped chain ends. Pd(dppf)Cl₂ yielded only one type of chain, and it had hydrogen end groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1454–1462, 2005     

Synthesis,Structure and Noncovalent Interactions Palladium（Ⅱ）Complexes with N—Benzoyl—β—phenylalaniate Dianion and Aromatic Diimine

Two palladium(II) complexes, [Pd(bipy)(BzPhe‐N,O)] and [Pd(phen)(BzPhe‐N,O)]·4H₂O were synthesized by reactions between Pd(bipy)Cl₂ and BzPheH₂ (N‐benzoyl‐β‐phenylalanine), Pd(phen) Cl₂ and BzPheH₂ in water at pH‐9, with their structures determined by X‐ray diffraction analysis. The Pd atom is coordinated by two nitrogen atoms of bipy (or phen), the deprotonated amido type nitrogen atom and one of the carboxylic oxygens of BzPhe (BzPhe = N‐benzoyl‐β‐phenylalaninate dianion). In the complex [Pd(phen) (BzFne‐N,O)] · 4H₂O, the side chain of phenylalanine is located above and approximately parallels to the coordination plane. Both the aromatic‐aromatic stacking interaction between the phenyl ring of phenylalanine and phen, and the metal ion‐aromatic interaction between the phenyl ring of phenylalanine and Pd(II) were observed. [Pd(bipy)(BzPhe‐N,O)] has the phenylalanyl side chain oriented outwards from the coordination plane, which is mainly due to the interaction between the carbonyl oxygen atom of the amido group and the phenyl ring of phenylalanine. The reason for the different orientation of phenylalanyl side chain in the complexes was suggested.     

Two Zinc(II) Coordination Polymers Based on Terphenyl‐2,2′,4,4′‐tetracarboxylate and Dipyridyl Ligands: Syntheses,Crystal Structures,and Luminescent Properties

Two coordination polymers, {[Zn₂(L)(bpy)] · 2H₂O}_n ( 1 ) and [Zn₂(L)(bpe)]_n ( 2 ) [H₄L = terphenyl‐2,2′,4,4′‐tetracarboxylic acid, bpy = 4,4′‐bipyridine, and bpe = 1,2‐bis(4‐pyridyl)ethane], were hydrothermally synthesized under similar conditions and characterized by elemental analysis, IR spectroscopy, TGA, and single‐crystal X‐ray diffraction analysis. Compound 1 has a 3D framework containing Zn–O–C–O–Zn 1D chains. Compound 2 exhibits a 3D framework, which features tubular channels. The channels are occupied by bpe molecules. The differences in the structures demonstrate that the auxiliary dipyridyl‐containing ligand has a significant effect on the construction of the final framework. Additionally, the fluorescent properties of the two compounds were also studied in the solid state at room temperature.     

Synthesis and photovoltaic properties of 2,6‐bis(2‐thienyl) benzobisazole and 4,8‐bis(thienyl)‐benzo[1,2‐B:4,5‐B′]dithiophene copolymers

In an effort to design efficient low‐cost polymers for use in organic photovoltaic cells the easily prepared donor–acceptor–donor triad of a either cis‐benzobisoxazole, trans‐benzobisoxazole or trans‐benzobisthiazole flanked by two thiophene rings was combined with the electron‐rich 4,8‐bis(5‐(2‐ethylhexyl)‐thien‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene. The electrochemical, optical, morphological, charge transport, and photovoltaic properties of the resulting terpolymers were investigated. Although the polymers differed in the arrangement and/or nature of the chalcogens, they all had similar highest occupied molecular orbital energy levels (?5.2 to ?5.3 eV) and optical band gaps (2.1–2.2 eV). However, the lowest unoccupied molecular orbital energy levels ranged from ?3.1 to ?3.5 eV. When the polymers were used as electron donors in bulk heterojunction photovoltaic devices with PC₇₁BM ([6,6]‐phenyl C₇₁‐butyric acid methyl ester) as the acceptor, the trans‐benzobisoxazole polymer had the best performance with a power conversion efficiency of 2.8%. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 316–324     

Effect of pH on the construction of CdII coordination polymers involving the 1,1′‐[1,4‐phenylenebis(methylene)]bis(3,5‐dicarboxylatopyridinium) ligand

Changing the pH value of a reaction system can result in polymers with very different compositions and architectures. Two new coordination polymers based on 1,1′‐[1,4‐phenylenebis(methylene)]bis(3,5‐dicarboxylatopyridinium) (L^2?), namely catena‐poly[[[tetraaquacadmium(II)]‐μ₂‐1,1′‐[1,4‐phenylenebis(methylene)]bis(3,5‐dicarboxylatopyridinium)] 1.66‐hydrate], {[Cd(C₂₂H₁₄N₂O₈)(H₂O)₄]·1.66H₂O}_n, (I), and poly[{μ₆‐1,1′‐[1,4‐phenylenebis(methylene)]bis(3,5‐dicarboxylatopyridinium)}cadmium(II)], [Cd(C₂₂H₁₄N₂O₈)]_n, (II), have been prepared in the presence of NaOH or HNO₃ and structurally characterized by single‐crystal X‐ray diffraction. In polymer (I), each Cd^II ion is coordinated by two halves of independent L^2? ligands, forming a one‐dimensional chain structure. In the crystal, these chains are further connected through O—H…O hydrogen bonds, leading to a three‐dimensional hydrogen‐bonded network. In polymer (II), each hexadentate L^2? ligand coordinates to six Cd^II ions, resulting in a three‐dimensional network structure, in which all of the Cd^II ions and L^2? ligands are equivalent, respectively. The IR spectra, thermogravimetric analyses and fluorescence properties of both reported compounds were investigated.     

Three one‐dimensional coordination polymers based on 1,1′‐bis(pyridin‐4‐ylmethyl)‐2,2′‐bi‐1H‐benzimidazole and HgX2 (X = Cl,Br and I)

A new 2,2′‐bi‐1H‐benzimidazole bridging organic ligand, namely 1,1′‐bis(pyridin‐4‐ylmethyl)‐2,2′‐bi‐1H‐benzimidazole, C₂₆H₂₀N₆, L or (I), has been synthesized and used to create three new one‐dimensional coordination polymers, viz.catena‐poly[[dichloridomercury(II)]‐μ‐1,1′‐bis(pyridin‐4‐ylmethyl)‐2,2′‐bi‐1H‐benzimidazole], [HgCl₂(C₂₆H₂₀N₆)]_n, (II), and the bromido, [HgBr₂(C₂₆H₂₀N₆)]_n, (III), and iodido, [HgI₂(C₂₆H₂₀N₆)]_n, (IV), analogues. Free ligand L crystallizes with two symmetry‐independent half‐molecules in the asymmetric unit and each L molecule resides on a crytallographic inversion centre. In structures (II)–(IV), the L ligand is also positioned on a crystallographic inversion centre, whereas the Hg centre resides on a crystallographic twofold axis. Compound (I) adopts an anti conformation in the solid state and forms a two‐dimensional network in the crystallographic bc plane viaπ–π and C—H...π interactions. The three Hg^II coordination complexes, (II)–(IV), have one‐dimensional zigzag chains composed of L and HgX₂ (X = Cl, Br and I), and the Hg^II centres are in a distorted tetrahedral [HgX₂N₂] coordination geometry. Complexes (III) and (IV) are isomorphous, whereas complex (II) displays an interesting conformational difference from the others, i.e. a twist in the flexible bridging ligand.     

The Crystal Structures of two Linearly Polymeric Copper(II) Complexes of 2, 2′‐Bipyridine with threefold Glycolato and Oxalato Bridges

The complex [Cu(HGLYO)₂(bipy)] ( I ) and two new copper(II) coordination polymers with the formulas {[Cu(GLYO)_1‐x(ox)_x(bipy)]·2.5H₂O}_n [GLYO = glycolato dianion, ox = oxalato dianion, bipy = 2, 2′‐bipyridine, x = 0.56 (in II ) or 0.71 (in III )] were synthesized using copper(II) glycolate as starting material and were characterized by IR, UV‐Vis and EPR spectrometry, by magnetic measurements ( II and III ), and by single‐crystal X‐ray diffractometry. Both II and III crystallized as one‐dimensional polymers composed of Cu₂O₂‐centred dimers with a Cu‐Cu distance of 3.282(1)Å (mean of II and III ) that are linked by Cu₂(OCO)₂ rings with a Cu‐Cu distance of 5.237(1)Å (mean of II and III ), both dianions acting as (μ‐1, 1, 2, 3) three‐way bridges connecting the two copper atoms of one dimer with one copper atom of a neighbouring dimer. Each copper atom is coordinated tetragonally in a CuN₂O₄ chromophore. In the mononuclear complex I the copper atom has a tetragonally distorted octahedral environment.     

Palladium(II) and Platinum(II) Complexes with Bisphosphanes, [S2C=C(CN)2]2– and [Se2C=C(CN)2]2– as Chelating Ligands

The palladium(II) and platin(II) 1, 1‐dicyanoethylene‐2, 2‐dithiolates [(L–L)M{S₂C=C(CN)₂}] (M = Pd: L–L = dppm, dppe, dcpe, dpmb; M = Pt: dppe, dcpe, dpmb) were prepared either from[(L–L)MCl₂] and K₂[S₂C=C(CN)₂] or from [(PPh₃)₂M{S₂C=C(CN)₂}] and the bisphosphane. Moreover, [(dppe)Pt{S₂C=C(CN)₂}]was obtained from [(1, 5‐C₈H₁₂)Pt{S₂C=C(CN)₂}] and dppeby ligand exchange. The 1, 1‐dicyanoethylene‐2, 2‐diselenolates[(dppe)M{Se₂C=C(CN)₂}] (M = Pd, Pt) were prepared from[(dppe)MCl₂] and K₂[Se₂C=C(CN)₂]. The oxidation potentials of the square‐planar palladium and platinum complexes were determined by cyclic voltammetry. The reaction of [(dcpe)Pd(S₂C=O)] with TCNE led to a ligand fragment exchange and gave the 1, 1‐dicyanoethylene‐2, 2‐dithiolate [(dcpe)Pd{S₂C=C(CN)₂}] in good yield.     

Synthesis and Characterization of Two New Chiral Copper(II) Compounds Constructed from (+)‐N‐Tosyl‐L‐glutamic Acid

Chiral coordination polymers have attracted intense interest mainly due to their potential applications. Hence, two new chiral copper(II) coordination polymers {[Cu(tsgluO)(H₂O)]₂·3H₂O}_n ( 1 ) and [Cu(tsgluO)(2,2′‐bipy)]_n ( 2 ) (H₂tsglu?(+)‐N‐tosyl‐l‐glutamic acid; 2,2′‐bipy?2,2′‐bipyridine) were synthesized in the absence or presence of 2,2′‐bipy ligand and structurally characterized. A single crystal X‐ray diffraction study revealed that compound 1 consists of a paddle‐wheel dicopper(II) core, which links other equivalents via four tsgluO^2? ligands to form a 1D double chain. Such a chain is further interconnected through weak π‐π stacking and hydrogen bonding interactions to form a 3D H‐bonded supramolecular structure with 1D channels hosting lattice water molecules. Whereas, compound 2 , containing the coordinating 2,2′‐bipy, gives rise to a ladder‐like 1D double chain. Antiferromagnetic interactions were observed in 1 and 2 .