Non-Symmetrical Sterically Challenged Phenanthroline Ligands and Their Homoleptic Copper(I) Complexes with Improved Excited-State Properties

A strategy is presented to improve the excited state reactivity of homoleptic copper–bis(diimine) complexes CuL₂⁺ by increasing the steric bulk around Cu^I whereas preserving their stability. Substituting the phenanthroline at the 2-position by a phenyl group allows the implementation of stabilizing intramolecular π stacking within the copper complex, whereas tethering a branched alkyl chain at the 9-position provides enough steric bulk to rise the excited state energy E⁰⁰. Two novel complexes are studied and compared to symmetrical models. The impact of breaking the symmetry of phenanthroline ligands on the photophysical properties of the complexes is analyzed and rationalized thanks to a combined theoretical and experimental study. The importance of fine-tuning the steric bulk of the N–N chelate in order to stabilize the coordination sphere is demonstrated. Importantly, the excited state reactivity of the newly developed complexes is improved as demonstrated in the frame of a reductive quenching step, evidencing the relevance of our strategy.     

Copper(I) Phosphinooxazoline Complexes: Impact of the Ligand Substitution and Steric Demand on the Electrochemical and Photophysical Properties

A series of seven homoleptic Cu^I complexes based on hetero-bidentate P^N ligands was synthesized and comprehensively characterized. In order to study structure–property relationships, the type, size, number and configuration of substituents at the phosphinooxazoline (phox) ligands were systematically varied. To this end, a combination of X-ray diffraction, NMR spectroscopy, steady-state absorption and emission spectroscopy, time-resolved emission spectroscopy, quenching experiments and cyclic voltammetry was used to assess the photophysical and electrochemical properties. Furthermore, time-dependent density functional theory calculations were applied to also analyze the excited state structures and characteristics. Surprisingly, a strong dependency on the chirality of the respective P^N ligand was found, whereas the specific kind and size of the different substituents has only a minor impact on the properties in solution. Most importantly, all complexes except C3 are photostable in solution and show fully reversible redox processes. Sacrificial reductants were applied to demonstrate a successful electron transfer upon light irradiation. These properties render this class of photosensitizers as potential candidates for solar energy conversion issues.     

Antiproliferative Homoleptic and Heteroleptic Phosphino Silver(I) Complexes: Effect of Ligand Combination on Their Biological Mechanism of Action

A series of neutral mixed-ligand [HB(pz)₃]Ag(PR₃) silver(I) complexes (PR₃ = tertiary phosphine, [HB(pz)₃]⁻ = tris(pyrazolyl)borate anion), and the corresponding homoleptic [Ag(PR₃)₄]BF₄ compounds have been synthesized and fully characterized. Silver compounds were screened for their antiproliferative activities against a wide panel of human cancer cells derived from solid tumors and endowed with different platinum drug sensitivity. Mixed-ligand complexes were generally more effective than the corresponding homoleptic derivatives, but the most active compounds were [HB(pz)₃]Ag(PPh₃) (5) and [Ag(PPh₃)₄]BF₄ (10), both comprising the lipophilic PPh₃ phosphine ligand. Detailed mechanistic studies revealed that both homoleptic and heteroleptic silver complexes strongly and selectively inhibit the selenoenzyme thioredoxin reductase both as isolated enzyme and in human ovarian cancer cells (half inhibition concentration values in the nanomolar range) causing the disruption of cellular thiol-redox homeostasis, and leading to apoptotic cell death. Moreover, for heteroleptic Ag(I) derivatives, an additional ability to damage nuclear DNA has been detected. These results confirm the importance of the type of silver ion coordinating ligands in affecting the biological behavior of the overall corresponding silver complexes, besides in terms of hydrophilic–lipophilic balance, also in terms of biological mechanism of action, such as interaction with DNA and/or thioredoxin reductase.     

铜配位聚合物[Cu(C5H6S5)(SCN)]∞的合成和结构研究(英)

The Copper(Ⅰ) supramolecular complexes of 4,5-bis(methylthio)-1,3-dithiole-2-thione (C₅H₆S₅), [Cu(C₅H₆S₅)(SCN)]_∞ 1 and [Cu(C₅H₆S₅)I]_∞ 2, have been prepared and characterized. X-ray structure analysis for complex 1 reveals that the infinite chain structure with polymeric stairs of different lengths is formed through the coordination mode (μ₃) of the thiocyanate bridges. The shorter interchain S…S contacts give rise to a three-dimensional network structure. CCDC: 215668.     

Syntheses and Crystal Structures of Two Silver(I) Complexes Isolated by the Reaction of [Ag(PPh3)2(MeCN)](SbF6) with a N6 Ligand

1 INTRODUCTION The polyaza macrocyclic and macrobicyclic mo-lecules have been extensively studied due to theirinclusion ability for neutral molecules, coordinationability for metal cations and versatile roles in thefields of recognition, transformation…     

Syntheses and Crystal Structures of Silver(I) Complexes by Depolymerizing [Ag(C(CPh)]n with a NP3 Ligand

Two silver(I) complexes were prepared by the reaction of [Ag(C(CPh)]n with NP3 [NP3 = N(CH2CH2PPh2)3] or with NP3 and [Cu(CH3CN)4]ClO4. Complex 1 [(Ag2Cl(NP3)2)(Ag5(C(CPh)6)] contains both NP3 and PhC(C- ligands. The complex cation is (Ag2Cl(NP3)2)+, in which two Ag(NP3)+ cations were bridged by a Cl- donor. The anion is (Ag5(C(CPh)6)-, where five Ag+ ions are linked by six C(CPh- to form a pentanuclear cluster. Complex 2 only contains NP3 ligand, where the silver center adopts a trigonal-bipyramidal geometry. Crystal data for 1: C133H116Ag7Cl3N2P6, Mr = 2789.54, triclinic, space group P, a = 13.0780(2), b = 15.3678(2), c = 31.2041(3) (A), α = 91.3928(7), β = 90.9328(8), γ = 96.0244(4)o, V = 6233.8(1) (A)3, T = 293(2) K, Z = 2, Dc = 1.486 g/cm3, F(000) = 2796, μ = 1.266 mm-1, the final R = 0.0746 and wR = 0.1953 for 16475 observed reflections with I > 2σ(I). Crystal data for 2: C42H42AgClNO4P3, Mr = 861.00, trigonal, space group R3, a = 17.451(1), b = 17.451(1), c = 11.3985(7) (A), V = 3006.0(3) (A)3, T = 293(2) K, Z = 3, Dc = 1.427 g/cm3, F(000) = 1326, μ = 0.731 mm-1, the final R = 0.0251 and wR = 0.0663 for 1499 observed reflections with I > 2σ(I).     

Ferro- and Antiferromagnetic Interactions in Oxalato-Centered Inverse Hexanuclear and Chain Copper(II) Complexes with Pyrazole Derivatives

Two novel copper(II) complexes of formulas {[Cu(4-Hmpz)₄][Cu(4-Hmpz)₂(µ₃-ox-κ²O¹,O²:κO^2′:κO^1′)(ClO₄)₂]}_n (1) and {[Cu(3,4,5-Htmpz)₄]₂[Cu(3,4,5-Htmpz)₂(µ₃-ox-κ²O¹,O²:κO^2′:κO^1′)(H₂O)(ClO₄)]₂[Cu₂(3,4,5-Htmpz)₄(µ-ox-κ²O¹,O²:κ²O^2′,O^1′)]}(ClO₄)₄·6H₂O (2) have been obtained by using 4-methyl-1H-pyrazole (4-Hmpz) and 3,4,5-trimethyl-1H-pyrazole (3,4,5-Htmpz) as terminal ligands and oxalate (ox) as the polyatomic inverse coordination center. The crystal structure of 1 consists of perchlorate counteranions and cationic copper(II) chains with alternating bis(pyrazole)(µ₃-κ²O¹,O²:κO^2′:κO^1′-oxalato)copper(II) and tetrakis(pyrazole)copper(II) fragments. The crystal structure of 2 is made up of perchlorate counteranions and cationic centrosymmetric hexanuclear complexes where an inner tetrakis(pyrazole)(µ-κ²O¹,O²:κ²O^2′,O^1′-oxalato)dicopper(II) entity and two outer mononuclear tetrakis(pyrazole)copper(II) units are linked through two mononuclear aquabis(pyrazole)(µ₃-κ²O¹,O²:κO^2′:κO^1′-oxalato)copper(II) units. The magnetic properties of 1 and 2 were investigated in the temperature range 2.0–300 K. Very weak intrachain antiferromagnetic interactions between the copper(II) ions through the µ₃-ox-κ²O¹,O²:κO^2′:κO^1′ center occur in 1 [J = −0.42(1) cm⁻¹, the spin Hamiltonian being defined as H = −J∑S_1,i · S_2,i+1], whereas very weak intramolecular ferromagnetic [J = +0.28(2) cm⁻¹] and strong antiferromagnetic [J’ = −348(2) cm⁻¹] couplings coexist in 2 which are mediated by the µ₃-ox-κ²O¹,O²:κO^2′:κO^1′ and µ-ox-κ²O¹,O²:κ²O^2′,O^1′ centers, respectively. The variation in the nature and magnitude of the magnetic coupling for this pair of oxalato-centered inverse copper(II) complexes is discussed in the light of their different structural features, and a comparison with related oxalato-centered inverse copper(II)-pyrazole systems from the literature is carried out.     

Syntheses and Crystal Structures of Silver(I) Complexes by Depolymerizing [Ag(C≡CPh)]_n with a NP_3 Ligand

1 INTRODUCTION Great attention has currently been paid to com-pounds formed by the reaction between phosphineand metal alkynyl building blocks[1]. The ligand NP3contains one tertiary nitrogen atom as well as threephosphorous atoms and bonds to the metal ions as atetradentate ligand, affording tetrahedral[2] or triangle-bipyrimidal geometry[3, . In other coordination ca- 4]ses, one[5, , two[7], three P donors[8, 6] …     

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide and Their Interaction with an Arene,Diverse Olefins,and an NTf2−‐Based Ionic Liquid

The chemistry of coinage metal bis(triflyl)imides of technological interest, CuNTf₂ and AgNTf₂, their synthesis and complexes with excess of comparatively weakly coordinating NTf₂^? as well as with ether, olefins, and the arene mesitylene are described. The existence of the solvent‐free pure phase [CuNTf₂]_∞ has not been evidenced so far. Contrary to the literature, in which the preparation of [CuNTf₂]_∞ is supposed to be carried out by reacting mesityl copper, [Cu(Mes)]₅, and HNTf₂, we found that in fact this reaction leads reproducibly to the interesting copper diarene sandwich complex [Cu(η³‐MesH)₂][Cu(NTf₂)₂] ( 1 ) (MesH=1,3,5‐trimethylbenzene). The unexpectedly stable molecular etherate [Cu(Et₂O)(NTf₂)] ( 2 ) turned out to be the best precursor for CuNTf₂ having only an inert and easily exchangeable solvent ligand. The coordination mode of NTf₂^? in 1 and 2 as well as in the hitherto unknown crystalline phase of [AgNTf₂]_∞ ( 3 ) is described. The complex formation, which takes place when dissolving 2 or 3 in the room temperature ionic liquid (RTIL) [emim]NTf₂ ([emim]⁺=1‐ethyl‐3‐methylimidazolium), has been studied. Furthermore, the reaction of 1 – 3 towards the diolefins 1,5‐cyclooctadiene (COD), 2,5‐norbornadiene (NBD) and isoprene (2‐methylbuta‐1,3‐diene) and towards ethylene has been investigated. The products 4 – 13 of these conversions have been isolated and fully characterized by NMR‐ and IR spectroscopies, mass spectrometry, and elemental‐ and XRD analyses. The potential of [Cu(η³‐MesH)₂][Cu(NTf₂)₂] ( 1 ), [Cu(Et₂O)(NTf₂)] ( 2 ) and [AgNTf₂]_∞ ( 3 ) as well as of [emim][M(NTf₂)₂] (M=Cu 4 , Ag 5 ) as chemisorbers for ethylene was studied by NMR spectroscopy.     

From Cluster to Polymer: Ligand Cone Angle Controlled Syntheses and Structures of Copper(I) Alkynyl Complexes

Copper(I) alkynyl complexes have attracted tremendous attention in structural studies, as luminescent materials, and in catalysis, and homoleptic complexes have been reported to form polymers or large clusters. Herein, six unprecedented structures of Cu^I alkynyl complexes and a procedure to measure the cone angles of alkynyl ligands based on the crystal structures of these complexes are reported. An increase of the alkynyl cone angle in the complexes leads to a modulation of the structures from polymeric [((PhC≡CC≡C)Cu)₂(NH₃)]_∞, to a large cluster [(TripC≡CC≡C)Cu]₂₀(MeCN)₄, to a relatively small cluster [(TripC≡C)Cu]₈ (Trip=2,4,6‐iPr₃‐C₆H₂). The complexes exhibit yellow‐to‐red phosphorescence at ambient temperature in the solid state and the luminescence behavior of the Cu₂₀ cluster is sensitive to acetonitrile.     

Cuprophilic interactions in luminescent copper(I) clusters with bridging bis(dicyclohexylphosphino)methane and iodide ligands: spectroscopic and structural investigations

Polynuclear copper(I) complexes with bridging bis(dicyclohexylphosphino)methane (dcpm) and iodide ligands, [Cu(2)(dcpm)(2)(CH(3)CN)(2)](BF(4))(2) (1), [Cu(2)(dcpm)(2)](BF(4))(2) (2), [(CuI)(3)(dcpm)(2)] (3), [(CuI)(4)(dcpm)(2)] (4), and [(CuI)(2)(dcpm)(2)] (5) were prepared and their structures determined by X-ray crystal analysis. The shortest Cu--Cu distance found in these complexes is 2.475(1) A for 3. Powdered samples of 1, 3, 4, and 5 display intense and long-lived phosphorescence with lambda(max) at 460, 626, 590, and 456 nm and emission quantum yields of 0.26, 0.11, 0.12, and 0.56 at room temperature, respectively. In the solid state, 2 displays both a weak emission at 377 and an intense one at 474 nm with an overall emission yield 0.42. The difference in emission properties among complexes 1-5 suggests that both Cu--Cu interaction and coordination around the copper(I) center affect the excited state properties. A degassed solution of 2 in acetone gives a bright red emission with lambda(max) at 625 nm at room temperature. The difference absorption spectra of the triplet excited states of 1-5 in acetonitrile show broad absorption peaks at 340-410 and 850-870 nm.     

New Mononuclear and Binuclear Cu(II), Co(II), Ni(II), and Zn(II) Thiosemicarbazone Complexes with Potential Biological Activity: Antimicrobial and Molecular Docking Study

Herein, we report the synthesis of eight new mononuclear and binuclear Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ methoxy thiosemicarbazone (MTSC) complexes aiming at obtaining thiosemicarbazone complex with potent biological activity. The structure of the MTSC ligand and its metal complexes was fully characterized by elemental analysis, spectroscopic techniques (NMR, FTIR, UV-Vis), molar conductivity, thermogravimetric analysis (TG), and thermal differential analysis (DrTGA). The spectral and analytical data revealed that the obtained thiosemicarbazone-metal complexes have octahedral geometry around the metal center, except for the Zn²⁺-thiosemicarbazone complexes, which showed a tetrahedral geometry. The antibacterial and antifungal activities of the MTSC ligand and its (Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺) metal complexes were also investigated. Interestingly, the antibacterial activity of MTSC- metal complexes against examined bacteria was higher than that of the MTSC alone, which indicates that metal complexation improved the antibacterial activity of the parent ligand. Among different metal complexes, the MTSC- mono- and binuclear Cu²⁺ complexes showed significant antibacterial activity against Bacillus subtilis and Proteus vulgaris, better than that of the standard gentamycin drug. The in silico molecular docking study has revealed that the MTSC ligand could be a potential inhibitor for the oxidoreductase protein.     

Synthesis, Crystal Structure and Luminescence of a Novel One-dimensional Silver(I)Sulfonate Complex with Pyrazine Ligand

The title complex,[Ag2(L1)2(Pyr)·2.5H20]1(L1=6-amino-1-naphthalenesulfonate anion,Pyr=pyrazine),has been synthesized and characterized by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1,with a=7.339(5),b=13.105(5),c=14.097(5)(A),α=84.377(5),β=76.921(5),γ=79.628(5)°,V= 1296.7(11)(A°)3,C48H50Ag4N8O17S4,Mr =1570.68,Z=1,Dc=2.011 g/cm3,/μ= 1.732 mm-1,F(000)=782,S=1.148,the final R=0.0436 and wR=0.1181 for 4130 observer reflections(I＞20(I)).Compound 1 shows a rare one- dimensional(1D)double chain, and the chains are further connected through secondary bonding,hydrogen bonds, and π-π interactions to generate a three-dimensional(3D)supramolecular structure.The luminescent property of 1 was also studied in the solid state at room temperture.     

Cationic Copper(I) Complexes as Highly Efficient Catalysts for Single and Double A3‐Coupling Mannich Reactions of Terminal Alkynes: Mechanistic Insights and Comparative Studies with Analogous Gold(I) Complexes

Cationic Cu?L complexes (L=Buchwald‐type phosphane) with N co‐ligands have been characterised by structural and spectroscopic properties. These copper(I) complexes are extremely active catalysts, far more active than analogous gold(I) complexes, to promote the single and double A³ coupling of terminal alkynes, pyrrolidine and formaldehyde. The activity data show the possible ways in which the solvent can influence the catalytic performance by limiting complex solubility, by solvent decomposition or instability of the copper(I) redox state. Isolation of copper(I) complexes that are likely to be the key catalytic species has allowed light to be shed on the reaction mechanism.     

Complexes of sterically-hindered diaminophosphinothiolate ligands with Rh(I), Ni(II) and Pd(II)

Two new sterically demanding diaminophosphinothiolate ligands (HL¹ and HL²) have been prepared and the X-ray crystal structure of the Li salt of HL² has been determined. The complex [Pd(L¹)₂] was fully characterized, but in contrast to other phosphinothiolates, complexes with the M(L)₃ stoichiometry could not be prepared. Reaction of LH¹ with Ni(II) led to cleavage of the arythiolate group and isolation of a thiolate bridged dimer, confirmed by an X-ray crystal structure. The Rh(I) complexes [Rh(nbd)L] (L = L¹, L²) were characterized including an X-ray structure.     

Thermal Studies of New Cu(I) and Ag(I) Complexes with Bipyridine Isomers

The complexes of the general formula MLSCN (M=Cu(I), Ag(I), L=2,2′-bipyridine=2-bipy, 4,4′-bipyridine=4-bipy or 2,4′-bipyridine=2,4′bipy) have been prepared and their IR spectra examined. The nature of metal-ligand coordination is discussed. Thermal decomposition in air of these complexes occurred in several successive endothermic and exothermic processes and the residue was Cu₂O and Ag, respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

Syntheses,Characterization and X‐Ray Structures of the first Copper(I) and Silver(I) Complexes with ATT (ATT = 6‐Aza‐2‐thiothymine)

The reaction of copper(I) chloride with 6‐aza‐2‐thiothymine (ATT, 1 ) and triphenylphosphane in methanol/chloroform gives [(ATT)CuCl(PPh₃)] ( 2 ) as a neutral complex. [(ATT)Ag(NO₃)(PPh₃)₂]·MeOH ( 3 ) can be obtained by the reaction of 1 with silver(I) nitrate and triphenylphosphane in methanol/chloroform in excellent yields and the single crystals of 3 can be obtained from acetonitril solution. Both complexes were characterized by infrared spectroscopy, elemental analyses as well as by X‐ray diffraction studies. Crystal data for 2 at —80 °C: space group I2/a with a = 1859.3(1), b = 1143.2(1), c = 2208.2(1) pm, β = 104.84(1)°, Z = 8, R₁ = 0.0355 and for 3 at —80 °C: space group P2₁/c with a = 1344.1(1), b = 1553.6(1), c = 1977, 3(3) pm, β = 105.26(1)°, Z = 4, R₁ = 0.0436.