Search

A series of coordination polymers (CPs), some of them featuring an unusual architecture, have been constructed by treatment of RSCH2C≡CCH2SR (R = C6H11L1, t-Bu L2) with CuX (X = Cl, Br, I) and CuX2. The outcome of the reaction of L1 with CuI depends on the metal-to-ligand ratio. Treatment of CuI with L1 in a 2 : 1 ratio affords the luminescent 2D CP [Cu4I4(μ-L1)2]n (CP1), whose grid-shaped network is built upon Cu4(μ3-I)4 cubane-like clusters as secondary building units (SBUs), interconnected via bridging L1 ligands. The use of a 1 : 1 ratio gives a material, whose particularity is the coexistence of two topological isomers within the unit cell. The first one, [{Cu(μ2-I)2Cu}(μ-L1)2]n (CP2), consists of 1D ribbons. The second isomer having a 0D topology, [{Cu(μ2-I)2Cu}(μ-L1)2] D1, is built upon discrete molecular complexes, whose dinuclear [Cu(μ2-I)2Cu] rhomboid-shaped core is spanned by two bridging L1 ligands. Mixing CuBr with L1 in MeCN solution leads to an isostructural material incorporating both 0D [{Cu(μ2-Br)2Cu}(μ-L1)2] complex D2 along with the 1D isomer [{Cu(μ2-Br)2Cu}(μ-L1)2]n (CP3). However, only the 1D CP [{Cu(μ2-Cl)2Cu}(μ-L1)2]n (CP4) results from complexation of L1 with CuCl. A stoichiometry-dependence is also noticed upon treatment of CuI with L2. Conducting the reaction in a 2 : 1 ratio yields the luminescent 2D CP [Cu4I4(μ-L2)2]n (CP5), whereas mixing equimolar amounts of the reactants produces 2D CP [{Cu(μ2-I)2Cu}(μ-L2)2]n (CP6). Structurally similar 2D CPs [{Cu(μ2-X)2Cu}(μ-L2)2]n (CP8 and CP9) result from complexation of L2 on CuBr or CuCl, respectively. Treatment of L2 with an excess of CuBr or CuBr2 in refluxing acetonitrile led to the transfer of Br to the acetylenic triple bond, generating an olefinic halogenated dithioether ligand Bu L3 that coordinates to CuBr to generate a 1D network [{Cu(μ2-Br)2Cu}(CH3CN)(μ-L3)]n (CP9). Using different conditions (propionitrile at 293 K), the reaction of L2 and excess CuBr led to the formation of a 2D network [{Cu(μ2-Br)2Cu}(μ-L2)(μ-L3)]n (CP10) incorporating both L2 and L3 in an alternating manner as assembling ligands. An isostructural chloro-analogue 2D [{Cu(μ2-Cl)2Cu}(μ-L2)(μ-L4)]n (CP11) was obtained using CuCl or CuCl2. The crystallographic work is completed by thermal analyses and investigation of the luminescence properties of CP1 and CP5 at 77 and 298 K. [ABSTRACT FROM AUTHOR]

This work aims to synthesize multifunctional materials with tunable emission properties. To pursue this, three isomeric ligands; 2-(1H-1,2,4-triazol-1-yl)pyridine (L1), 3-(1H-1,2,4-triazol-1-yl)pyridine (L2) and 4-(1H-1,2,4-triazol-1-yl)pyridine (L3) were reacted with CuI to afford three different coordination polymers, [Cu2(μ3-I)2(L1)2]nCP1, [Cu2(μ2-I)2(L2)2]nCP2 and [Cu(μ2-I)(L3)]nCP3, respectively. CP1 consists of a 1D chain comprising double-stranded Cu2I2 secondary building units (SBUs), where each copper is coordinated with the triazolyl nitrogen of the ligand on each side of the chain while the pyridine nitrogen remains pendant. Contrary to this, both pyridine and triazolyl nitrogens of L2 and L3 coordinate to Cu to give 1D and 2D CP2 and CP3, respectively. CP2 has a discrete Cu2I2 rhomboid SBU bridged by two L2 ligands, whereas CP3 has Cu–I single chains bridged by two L3 ligands to give a 2D sheet structure. All three coordination polymers are emissive at room temperature with the emission colour varying from green and yellow to orange with a λmax of 538, 575 and 600 nm, respectively for CP1 to CP3. CP1 and CP3 show luminescence thermochromism on lowering the temperature from 298 K to 77 K, changing hues from green to blue and orange to yellow, respectively. In addition to unique emission properties, these CPs exhibit semiconductor behaviour, with electrical conductivity in the range of 10−7 S cm−1. It is proposed that the presence of the Cu2I2 double-stranded chain provides a better and continuous overlap of copper and iodine orbitals, giving better conductivity to CP1 compared to CP2 and CP3. [ABSTRACT FROM AUTHOR]

Cu(I)-based coordination polymers (CPs) are known as efficient emissive materials providing an eco-friendly and cost-effective platform for the development of various functional materials and sensors. In addition to the nature of the metal center, organic ligands also play a crucial role in controlling the emissive properties of coordination polymers. Herein, we report on the synthesis of dithiane- and dithiolane-substituted triphenylamine ligands L1 and L2. These ligands were found to be emissive both in the solid state and in solution. In addition, these ligands exhibit solvatochromic behaviour due to the twisted intramolecular charge transfer (TICT) phenomenon. Next, coordination behaviour of these ligands was explored with Cu(I)X salts (X = Br and Cl) and four new 1D coordination polymers [{Cu(μ2-X)2Cu}(μ2-L)]n, CP1 (X = Br, L = L1), CP2 (X = Cl, L = L1), CP3 (X = Br, L = L2), and CP4 (X = Cl, L = L2) were synthesized and crystallographically characterized. The emission behaviour of all the CPs suggests ligand-centered transitions. On mechanical grinding, emission maxima (λem) for CP1 and CP2 were blue-shifted, whereas for CP3 and CP4 red-shifts were observed. All CPs were found to emit at 448 nm with increased intensity after grinding. It is supposed that grinding is responsible for a change in the spatial arrangement (dihedral angles) of the phenyl groups of triphenylamine, causing the observed emission shifts. Furthermore, the higher emission intensity after grinding suggests the occurrence of a similar phenomenon as an aggregation-induced quenching in these CPs. [ABSTRACT FROM AUTHOR]

In order to investigate the coordination chemistry of O-alkyl N-aryl thiocarbamate ligands toward coinage metals, CuBr was reacted with one equivalent of MeOC(=S)N(H)Ph L in MeCN solution to afford the 1D-polymeric title compound [{Cu(μ2-Br)2Cu}{μ2-MeOC(=S)N(H)Ph}2]n CP1. Compound 1 was characterized by IR spectroscopy and an elemental analysis. The formation of a polymeric 1D ribbon built upon μ2-bridging bromido and thione ligands via the C=S bond was ascertained by a single-crystal X-ray diffraction study performed at 100 K. In the presence of PAr3 (Ar = Ph, p-Tol), the polymer chain was broken to yield the mononuclear complexes [(Ar3P)2Cu{MeOC(=S)N(H)Ph}Br] C1 and C2. [ABSTRACT FROM AUTHOR]

With the aim to elaborate novel and inexpensive sulphur-rich materials featuring unusual network architectures, the coordination chemistry of the tetradentate thiaheterocycle 1,2-di(1,3-dithian-2-yl)ethane L1 ligand toward CuX and HgX2 salts was investigated. When L1 is reacted with CuI in a 1 : 1 ratio, a two-dimensional CP [{Cu(μ2-I)2Cu}(μ2-L1)]n (CP1) is formed, in which two out of four S atoms of L1 remain non-coordinated. Upon treatment of L1 with CuI in a 1 : 2 ratio, [{Cu(μ2-I)2Cu}(μ4-L1)]n (CP2) is obtained, in which each S atom of L1 coordinates to one copper centre forming a 2D layer. Raising the ligand-to-CuI ratio to 1 : 4 affords the 2D material [{Cu(μ4-I)(μ2-I)Cu}2(μ4-L1)]n (CP3), in which [Cu(μ4-I)(μ2-I)Cu]n ribbons are interconnected through μ4-bridging L1 ligands. Upon the reaction of L1 with CuBr in a 1 : 2 ratio, a 2D CP [{Cu(μ2-Br)}2(μ2-L1)(μ4-L1)0.5]n (CP4) is formed at room temperature and a 2D CP [{Cu(μ2-Br)}2(μ4-L1)]n (CP5) is obtained in refluxing propionitrile. In CP4 and CP5 Cu atoms are bridged by a single μ2-Br ligand giving rise to [Cu(μ2-Br)Cu]n ribbons but CP4 differs from CP5 from the metal to ligand ratio and the presence of non-coordinated S atoms. Employing a 1 : 3 ratio, a 1D ribbon [{Cu(μ2-Br)}3(MeCN)(μ4-L1)]n (CP6) is generated, that contains both tetrahedral and trigonal copper atoms. CP6 also presents two different L1 ligands that differ by the coordination mode of the sulphur atoms (S acting as 2 or as 4 electron-donor). With CuCl, a 2D network [{Cu(μ2-Cl)2Cu}(μ4-L1)]n (CP7) is generated. L1 coordinates also on HgX2 salts to yield CPs whose architecture depends on the ligand-to-metal ratio. The meander-shaped 1D CP [(HgI2)(μ2-L1)]n (CP8) and the linear 1D ribbons of CP9 and CP12 [(HgX2)(μ2-L1)]n (X = Br, Cl) result from treatment with L1 in a 1 : 1 ratio. In the case of HgBr2, using a 2 : 1 metal-to-ligand ratio, 1D polymeric [{BrHg(μ2-Br)2HgBr}(μ2-L1)] (CP10) is produced. HgI2 and HgBr2 have also been reacted with 2-methyl-1,3-dithiane L2 yielding the molecular complexes [{IHg(μ2-I)2HgI}(κ1-L2)2] (D1) and [HgBr2(κ1-L2)2] (M1). Two heterometallic 1D materials [{IHg(μ2-I)2HgI(μ2-I)2{Cu(RCN)2}2(μ2-L1)]n (CP13) and (CP14) result from the treatment of CP1 with HgI2 in MeCN or EtCN. Performing the reaction of CP1 with HgBr2 in acetonitrile produces the zwitterionic 2D material [Cu(MeCN)}(HgIBr2)(μ2-L1)1.5]n (CP15). [ABSTRACT FROM AUTHOR]

The polymeric title compound, [Cu2Br2(C4H8S)2]n, CP1, represents an example of a two-dimensional coordination polymer resulting from reaction of CuBr with tetrahydrothiophene (THT) in MeCN solution. The two-dimensional layers consist of two different types of rhomboid-shaped dinuclear Cu(2-Br)2Cu secondary building units (SBUs); one with a quite loose Cu=Cu separation of 3.3348 (10) A and a second one with a much closer intermetallic contact of 2.9044 (9) A. These SBUs are interconnected through bridging THT ligands, in which the S atom acts as a four-electron donor bridging each Cu(2-Br)2Cu unit in a=2-bonding mode. In the crystal, the layers are linked by very weak C= H=Br hydrogen bonds with H=Br distances of 2.95 A, thus giving rise to a three-dimensional supramolecular network. [ABSTRACT FROM AUTHOR]

The first title compound, C29H24S2, L1, represents an example of an anthracenebased functionalized dithioether, which may be useful as a potential chelating or terminal ligand for coordination chemistry. This dithioacetal L1 crystallizes in the monoclinic space group P21/c. The phenyl rings of the benzyl groups and that of the anthracene unit form dihedral angles of 49.21 (4) and 58.79 (5) and the crystal structure displays short C-H contacts. Surprisingly, when attempting to coordinate L1 to [PdCl2(PhCN)2], instead of the targeted chelate complex [PdCl2(2-L1)], a cleavage reaction leads to the formation of the centrosymmetric hexanuclear cyclic cluster of composition [Pd6(2-SCH2Ph)12] Pd6, or [Pd6(C7H7S)12]C14H8O2. This tiara-shaped hexamer crystallizing in the triclinic space group P1 consists of six approximately square planar Pd(II)S4 centers, which are interconnected through twelve 2-bridging benzyl thiolate groups. The Pd=Pd contacts range from 3.0892 (2) to 3.1609 (2) A ° and can be considered as weakly bonding. The unit cell of Pd6 contains also a cocrystallized anthracene-9,10-dione molecule. [ABSTRACT FROM AUTHOR]

The polymeric title compound, [Cu2(C2H3N)2(C3H6S2)2](PF6)2, represents an example of a one-dimensional coordination polymer resulting from the reaction of [Cu(MeCN)4][PF6] with 1,3-dithiolane. The cationic one-dimensional ribbon consists of two copper(I) centers each ligated by one acetonitrile molecule and interconnected through two bridging 1,3-dithiolane ligands. One S-donor site of each ligand is κ¹-bound to Cu, whereas the second S atom acts as a four-electron donor, bridging two Cu atoms in a κ4-bonding mode. The positive charge of each copper cation is compensated for by a hexafluoridophosphate counter-ion. In the crystal, the polymer chains are linked by a series of C--H ⋯F hydrogen bonds, forming a supramolecular framework. [ABSTRACT FROM AUTHOR]

The syntheses of medium-nuclearity very-mixed metal clusters by an unusual combination of core expansion and metal exchange upon reacting M[Ir.sub.3][(CO).sub.11]([eta]-L) (M = Mo, W and L = [C.sub.5][H.sub.5], [C.sub.5]H[Me.sub.4], [C.sub.5][Me.sub.5]) with [[M[(CO).sub.3]([eta]-L)].sup.-] (M = Mo, W and L = [C.sub.5]H[Me.sub.4], [C.sub.5][Me.sub.5]) is reported. The spectroscopic data has suggested that the electron density at these dispartate-metal-containing cluster cores is tunable by progressive cyclopentadienyl alkylation.

Reactions of tungsten-iridium clusters with tungsten phenylethynyl, diruthenium ethynidyl, or ditungsten butadiyndiyl complexes afford a range of products of the same or higher nuclearity. The focus of the study is on molybdenum/tungsten-iridium clusters, reaction with alkynes having afforded products involving alkyne coordination, dimerization, or C triple bond C scission.

The photoisomerization properties of new metallochromophores and the macroscopic molecular orientation of the corresponding doped and star-shaped NLO-polymer films are presented. The results indicate the possibility to generate a new class of nonlinear quadratic materials, capable of answering the request of stability and efficiency in conjunction with the symmetry control.