Synthesis, optical spectroscopy, structural, and DFT studies on dimeric iodo-bridged Copper(I)complexes

Three new iodo-bridged copper(I)complexes of the type [CuI(PPh 3 )L] 2 , where L = Ar–≡–C 5 H 4 N, Ar = phenyl (C 1 ), biphenyl (C 2 )and flourenyl (C 3 )have been synthesized via coordination-driven self-assembly processes. Two of Cu(I)complexes, C 2 and C 3 , have been characterized by single-crystal X-ray diffraction studies. The complexes have two molecules of the P-donor ligand and two molecules of the N-donor ligand in trans configurations, supporting the central Cu 2 I 2 unit. Absorption properties of the complexes have been investigated. Extensive DFT calculation has been carried out to delineate the influence of aromatic spacers on the optical properties and the nature of excited states. The ease of synthesis of these Cu(I)dimers and the wide range of ethynylpyridine supporting ligands that can be incorporated highlights the potential for these materials to form polymers by linking through the ethylylpyridine ligands. </p

Two is Better Than One? Investigating the Effect of Incorporating Re(CO)₃Cl Side-Chains into Pt(II) Diynes and Polyynes

Pt(II) di-ynes and poly-ynes incorporating 5,5’- and 6,6’-disubstituted 2,2’-bipyridines were prepared following conventional Sonogashira and Hagihara dehydrohalogenation reaction protocols. Using Pt(II) dimers and polymers as a rigid-rod backbone, four new hetero-bimetallic compounds incorporating Re(CO)3Cl as a pendant functionality in the 2,2’-bipyridine core were obtained. The new hetero-bimetallic Pt-Re compounds were characterized by analytical and spectroscopic techniques. The solid state structures of a Re(I)-coordinated diterminal alkynyl ligand and a representative model compound were determined by single-crystal X-ray diffraction. Detailed photo-physical characterization of the hetero-bimetallic Pt(II) di-ynes and poly-ynes was carried out. We find that the incorporation of the Re(CO)3Cl pendant functionality in the 2,2’-bipyridine-containing main-chain Pt(II) di-ynes and poly-ynes has a synergistic effect on the optical properties, red shifting the absorption profile and introducing strong long-wavelength absorptions. The Re(I) moiety also introduces strong emission into the monomeric Pt(II) di-yne compounds, whereas this is suppressed in the poly-ynes. The extent of the synergy depends on the topology of the ligands. Computational modelling was performed to compare the energetic stabilities of the positional isomers and to understand the microscopic origin of the major optical absorptions. We find that 5,5’-disubstituted 2,2’-bipyridine systems are better candidates in terms of yield, photophysical properties and stability than their 6,6’-substituted counterparts. Overall, this work provides an additional synthetic route to control the photo-physical properties of metalla-ynes for a variety of optoelectronic applications

Two is Better Than One? Investigating the Effect of Incorporating Re(CO)₃Cl Side-Chains into Pt(II) Diynes and Polyynes

Pt(II) di-ynes and poly-ynes incorporating 5,5’- and 6,6’-disubstituted 2,2’-bipyridines were prepared following conventional Sonogashira and Hagihara dehydrohalogenation reaction protocols. Using Pt(II) dimers and polymers as a rigid-rod backbone, four new hetero-bimetallic compounds incorporating Re(CO)3Cl as a pendant functionality in the 2,2’-bipyridine core were obtained. The new hetero-bimetallic Pt-Re compounds were characterized by analytical and spectroscopic techniques. The solid state structures of a Re(I)-coordinated diterminal alkynyl ligand and a representative model compound were determined by single-crystal X-ray diffraction. Detailed photo-physical characterization of the hetero-bimetallic Pt(II) di-ynes and poly-ynes was carried out. We find that the incorporation of the Re(CO)3Cl pendant functionality in the 2,2’-bipyridine-containing main-chain Pt(II) di-ynes and poly-ynes has a synergistic effect on the optical properties, red shifting the absorption profile and introducing strong long-wavelength absorptions. The Re(I) moiety also introduces strong emission into the monomeric Pt(II) di-yne compounds, whereas this is suppressed in the poly-ynes. The extent of the synergy depends on the topology of the ligands. Computational modelling was performed to compare the energetic stabilities of the positional isomers and to understand the microscopic origin of the major optical absorptions. We find that 5,5’-disubstituted 2,2’-bipyridine systems are better candidates in terms of yield, photophysical properties and stability than their 6,6’-substituted counterparts. Overall, this work provides an additional synthetic route to control the photo-physical properties of metalla-ynes for a variety of optoelectronic applications

Dicopper(I) Complexes Incorporating Acetylide-functionalized Pyridinyl-based Ligands::Synthesis, Structural and Photovoltaic Studies

Heteroaryl incorporated acetylide-functionalized pyridinyl ligands (<b>L1–L6</b>) with the general formula Py-CC-Ar (Py = pyridine and Ar = <i>thiophene-2-yl</i>, 2,2′<i>-bithiophene]-5-yl</i>, 2,2′<i>:5</i>′,2″<i>-terthiophene]-5-yl</i>, <i>thieno­[2,3-<i>b</i>]­thiophen-2-yl</i>, <i>quinoline-5-yl</i>, <i>benzo­[c]­[1,2,5]­thiadiazole-5-yl</i>) have been synthesized by Pd(0)/Cu­(I)-catalyzed cross-coupling reaction of 4-ethynylpyridine and the respective heteroaryl halide. Ligands <b>L1–L6</b> were isolated in respectable yields and characterized by microanalysis, IR spectroscopy, ¹H NMR spectroscopy, and ESI-MS mass spectrometry. A series of dinuclear Cu­(I) complexes <b>1</b>–<b>10</b> have been synthesized by reacting <b>L1–L6</b> with CuI and triphenylphosphine (PPh₃) (<b>R1</b>) or with an anchored phosphine derivative, 4-(diphenylphosphino) benzoic acid (<b>R2</b>)/2-(diphenylphosphino)­benzenesulfonic acid (<b>R3</b>), in a stoichiometric ratio. The complexes are soluble in common organic solvents and have been characterized by analytical, spectroscopic, and computational methods. Single-crystal X-ray structure analysis confirmed rhomboid dimeric structures for complexes <b>1</b>, <b>2</b>, <b>4</b>, and <b>5</b>, and a polymeric structure for <b>6</b>. Complexes <b>1</b>–<b>6</b> showed oxidation potential responses close to 0.9 V vs Fc^0/+, which were chemically irreversible and are likely to be associated with multiple steps and core oxidation. Preliminary photovoltaic (PV) results of these new materials indicated moderate power conversion efficiency (PCE) in the range of 0.15–1.56% in dye-sensitized solar cells (DSSCs). The highest PCE was achieved with complex <b>10</b> bearing the sulfonic acid anchoring functionality

Synthesis, optical spectroscopy, structural, and DFT studies on dimeric iodo-bridged Copper(I)complexes

Three new iodo-bridged copper(I)complexes of the type [CuI(PPh 3 )L] 2 , where L = Ar–≡–C 5 H 4 N, Ar = phenyl (C 1 ), biphenyl (C 2 )and flourenyl (C 3 )have been synthesized via coordination-driven self-assembly processes. Two of Cu(I)complexes, C 2 and C 3 , have been characterized by single-crystal X-ray diffraction studies. The complexes have two molecules of the P-donor ligand and two molecules of the N-donor ligand in trans configurations, supporting the central Cu 2 I 2 unit. Absorption properties of the complexes have been investigated. Extensive DFT calculation has been carried out to delineate the influence of aromatic spacers on the optical properties and the nature of excited states. The ease of synthesis of these Cu(I)dimers and the wide range of ethynylpyridine supporting ligands that can be incorporated highlights the potential for these materials to form polymers by linking through the ethylylpyridine ligands. </p