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Metal-Containing Conjugated Polymers
Published in John R. Reynolds, Barry C. Thompson, Terje A. Skotheim, Conjugated Polymers, 2019
Christopher M. Brown, Michael O. Wolf
In the late 2000s, our group became interested in the possibility of pressure-induced conjugation changes in conjugated ligands attached to metals. This resulted in the synthesis and characterization of the first example of a metal complex containing a terthienyl diphosphine ligand, which exhibited ligand-based tribochromic luminescence (Kuchison, Wolf, and Patrick, 2009). A number of organic molecules are known to undergo these conjugation changes. For example the π-π* absorption bands of poly(3-alkylthiophenes) red-shift at high applied pressure due to increased conjugation resulting from packing of the alkyl substituents under pressure. The goal of this work was to induce tribochromic thiophene-based luminescence under milder conditions, and in order to achieve this the oligomer substituents must be chosen to allow for more than one stable solid structure to exist at near-ambient pressures. Au(I) complexes in a Type I binding mode were chosen due to gold metal centers primarily affecting structure while having minimal electronic effects with the conjugated moiety.
Transition metal-catalyzed hydrogenation
Published in Ilya D. Gridnev, Pavel A. Dub, Enantioselection in Asymmetric Catalysis, 2016
Totally, there are 12 possible ways of the double bond cis-chelating coordination in 2 diastereomers of octahedral nonchelating dihydride intermediates I and I’ in the case of a Rh complex with C2-symmetric diphosphine ligand. However, already early empirical considerations suggested that the hydride trans to phosphorus atom must be transferred in the migratory insertion step.45 This hypothesis was amply supported by the results of low-temperature experiments (e.g., Figure 1.4), and the structures of all known monohydride intermediates. Hence, the analysis can be restricted to the eight structures originating from two nonchelating complexes I and I’ (Scheme 1.30).
Applications of Green Chemistry Principles in the Pharmaceutical Industry
Published in Vera M. Kolb, Green Organic Chemistry and Its Interdisciplinary Applications, 2017
The green synthesis can be achieved by the use of a chiral transition metal complex as a catalyst for the hydrogenation of the nonchiral precursor. The catalyst is a cationic rhodium complex, containing a chelating diphosphine ligand Ethane-1,2-diylbis[(2-methoxyphenyl)phenylphosphane] (DiPAMP) with two chiral phosphorous atoms. The resulting hydrogenation product is chiral, with a high enantioselectivity (95% enantiomeric excess). The hydrolysis removes protecting groups and gives l-DOPA. Dr. William S. Knowles, from Monsanto Company in St. Louis, Missouri, shared the 2001 Nobel Prize for the discovery and application of this catalyst (Ahlberg, 2001; Knowles, 2001). The reaction is shown in Figure 10.6.
Synthesis, spectral properties and terahertz time domain spectroscopy of two copper(I) complexes based on bisphosphine and bisazo ligands
Published in Journal of Coordination Chemistry, 2022
Fu-Zhen Hu, Lan Zhang, Guan-Yu Jin, Zhen-Zhou Sun, Guo Wang, Hong-Liang Han, Zhong-Feng Li, Yu-Ping Yang, Qiong-Hua Jin, Fan Zhang
Mixed ligand Cu(I) diphosphine diimine complexes (such as [Cu(N∧N)(P∧P)] system) and their luminescence properties have been studied. In these complexes, nitrogen and phosphorus ligands affect the supramolecular structure [14,15]. N,N-bis[(diphenylphosphino)methyl]-2-pyridinamine (bdppmapy) is a diphosphine ligand that can be coordinated as a bridging or chelating ligand. In this paper, bdppmapy was selected as phosphorus ligand as aromatic rings of larger volume can provide a large spatial steric resistance. According to the hard-soft-acid-base (HSAB) theory, bdppmapy can easily coordinate with Cu(I) to improve crystal quality. Impressive performance of the heteroleptic [Cu(N+∧N)(P∧P)] counterparts have drawn attention because of its superior performance with higher emission efficiency, longer excited state lifetime and wider tuning range than [Cu(N+∧N)2]+ systems [16,17].
Diiron carbonyl complexes containing bridging 1,3-bis(diphenylphosphino)propane or monosubstituted tris(3-fluorophenyl)phosphine: synthesis, characterization, X-ray crystallography, and electrochemistry
Published in Inorganic and Nano-Metal Chemistry, 2022
Lin Yan, Ling-Hui Wang, Wen-Jing Tian, Xu-Feng Liu, Yu-Long Li, Xing-Hai Liu, Zhong-Qing Jiang
The three-atom dithiolate bridged diiron complexes have received great attention in past two decades; however, the two-atom dithiolate bridged diiron complexes have received little attention. In the present work, we selected a diiron ethane-1,2-dithiolate complex [Fe2(CO)6(µ-SCH2CH2S)] (1) as the parent complex because the structure of complex 1 is similar to complex [Fe2(CO)6(µ-SCH2CH2CH2S)]. Moreover, we undertook the CO substitution of complex 1 with two phosphine ligands dppp and tris(3-fluorophenyl)phosphine because we believe that the phosphine ligands are easily available and can mimic the cyanides found in the active site of [FeFe]-hydrogenases. Herein, in this article, we describe the synthesis, characterization, and X-ray crystal structures of two diiron complexes containing a bridging diphosphine ligand or a monophosphine ligand as the biomimics for the active site of [FeFe]-hydrogenases. In addition, the electrochemical properties of these complexes were also studied.
Advances in the development of Cu(I) complexes as optical oxygen-sensitive probes
Published in Journal of Coordination Chemistry, 2022
Hongcui Yu, Bo Yu, Yajiao Song
A further leap in this path was taken by the same group in 2017 [81]. A series of new Cu(I) complexes bearing diimine (2,9-dimethyl-1,10-phenanthroline (dmp) or 4,7-dimethyl-1,10-phenanthroline (47dmp)) and dodecafluorinated diphosphine (1,2-bis(bis(pentafluoeophenylphosphino)ethane (dfppe)) ligands were synthesized and characterized. They demonstrated that the introduction of pentafluorophenyl groups in the diphosphine ligand moieties markedly increases contribution of ligand centered transition, resulting in a long-lived excited state for the corresponding Cu(I) complex. The blue emission of [Cu(dmp)(dfppe)]+PF6− (14, see Figure 5) in the solid state under argon is much stronger than in air. In the solid state, the lifetime of 14 is similarly strongly oxygen responsive (τair = 2.4 μs (85%), 0.5 μs (15%) and τargon = 160 μs (88%), 22 μs (12%)). It is one of the longest values among all Cu(I) complexes with diimine and diphosphine ligands, and it may be crucial for improving the solid-state sensing capabilities of the blue reversible oxygen responsive emission.