Metal Alkynyl Complexes Research Articles

Long-Range Corrected DFT Calculations of First Hyperpolarizabilities and Excitation Energies of Metal Alkynyl Complexes.

The performance of the CAM-B3LYP, ωB97X and LC-BLYP long-range corrected density functional theory methods in the calculation of molecular first hyperpolarizabilities (β) and low-lying charge transfer (CT) excitation energies of the metal alkynyl complexes M(C≡C-4-C6 H4 -1-NO2 )(κ2 -dppe)(η5 -C5 H5 ) [M=Fe (1), Ru (2), Os (3)] and trans-[Ru{C≡C-(1,4-C6 H4 C≡C)n -4-C6 H4 -1-NO2 }Cl(κ2 -dppm)2 ] [n=0 (4), 1 (5), 2 (6)] was assessed. The BLYP, B3LYP and PBE0 standard exchange-correlation functionals and the Hartree-Fock method were also examined. The BLYP functional was shown to perform poorly in the calculation of β and low-energy CT transitions. The hybrid functionals (B3LYP and PBE0) showed significant improvement over the pure functional BLYP, but overestimated the hyperpolarizability ratios and the wavelengths of the lowest energy metal-to-ligand CT transitions for 5 and 6. The effect of long-range corrections is noteworthy, particularly for the larger complexes, improving the calculation of β ratios for 4-6. However, CAM-B3LYP, ωB97X, and LC-BLYP considerably overestimated the low-lying CT energies. PBE0 was found to give the best transition energy match for 4. The influence of the phenylene ring orientation in the alkynyl ligand on the calculated properties is substantial, particularly for the larger complexes. For these types of calculations, a basis set with diffuse functions (at least 6-31+G(d)) for the heavy elements is recommended.

Assembly of strongly phosphorescent hetero-bimetallic and -trimetallic [2]catenane structures based on a coinage metal alkynyl system.

Homo-metallic metal alkynyl complexes exhibit interesting catenane structures, but their hetero-metallic catenane counterparts are under-developed. In this work, we report rare examples of bimetallic Au-Cu (DtbpC[triple bond, length as m-dash]C- ligand; Dtbp = 3,5-di-tert-butylphenyl), Au-Ag ( t BuC[triple bond, length as m-dash]C- ligand), and Au-Cu, Au-Ag (C6-FluoC[triple bond, length as m-dash]C- ligand; C6-Fluo = 9,9-dihexyl-9H-fluoren-2-yl) complexes as well as a trimetallic Au-Ag-Cu (C6-FluoC[triple bond, length as m-dash]C- ligand) complex, which feature [2]catenane structures. The formation of the [2]catenane structure is significantly affected by the coinage metal ion(s) and change of the structure of the alkynyl ligand. These hetero-metallic [2]catenane structures are strongly luminescent with tunable emission λ max from 503 to 595 nm and Φ values up to 0.83.

Theoretical study of the effect of π-conjugated transmitter of D–π–A ruthenium systems on the quadratic NLO properties

In this work, we present the theoretical quantum chemical calculation of effect of π-conjugated transmitter variation of two types of acceptor based on barbituric acid (with R=H or R=Me) of the organometallic molecules. The one-photon absorption OPA, dipole moments (μ), first hyperpolarizabilities (β), frontier molecular orbital energies based on the semi-empirical ZINDO/1 method within a framework of the restricted Hartree–Fock approach have been calculated. This method was employed to study relationship between first hyperpolarizabilities and the a kind of transmitter of π-conjugated ligand in the investigated organometallic compounds. Using this method, we found excellent agreement with experimental S1 → S0 excitation energies. The investigated complexes show large optical second order nonlinearities in comparison with metal alkynyl and related complexes.

Anion-Directed Solid-State Structures of Copper(I) and Silver(I) Adducts of Ruthenium Ethyne-1,2-diyl Compounds

A number of group 11 salts, [MX] (M = Ag, X– = –O3SCF3, –O2CCF3, BF4–; M = Cu; X = Cl, Br) and [Cu(MeCN)4][PF6], were found to react in varying stoichiometries with ethyne-1,2-diyl compounds, [{Ru(CO)2(η-C5H4R)}2(μ2-C≡C)] (R = H, Me), to give a number of complex cations. The trication salts [Ag3({Ru(CO)2(η-C5H4Me)}2(μ2-η1:η1-C≡C))3](O3SCF3)3, [Ag3({Ru(CO)2(η-C5H4R)}2(μ2-η1:η1-C≡C))({Ru(CO)2(η-C5H4R)}2(μ2-η1:η2-C≡C))2](BF4)3, and [Cu3({Ru(CO)2(η-C5H4R)}2(μ2-η1:η2-C≡C))({Ru(CO)2(η-C5H4R)}2(μ2-η2-C≡C))](PF6)3 result from the use of the respective anion salts in their syntheses. Coordination of Ag+ by the ethyne-1,2-diyl complexes in the presence of F3CCO2– yields the tetranuclear complexes [Ag4({Ru(CO)2(η-C5H4R)}2(μ2-η2-C≡C))2](μ2-O2CCF3)4 (R = H, Me). The reaction of CuCl does not afford the discrete dimeric complexes normally observed for internal alkynes and metal alkynyl complexes but, rather, the 1-D polymer [Cu2(μ-Cl)2({Ru(CO)2(η-C5H4R)}2(η2-C≡C))](∞|∞), while CuBr gives the discrete dimer motif known in the literature. The solution structures at 1/2, 1/1, and 2/1 stoichiometries of Ag+/[{Ru(CO)2(η-C5H5)}2(μ2-C≡C)] have been probed spectroscopically, and the {Ru(CO)2(η-C5H4R)} environments appear to be equivalent and, likewise, the resonances attributable to their C≡C units. In a subsequent reaction of [{Ru(CO)2(η-C5H4R)}2(μ2-C≡C)] and AgBF4 use of a strict Ag+/ethyne-1,2-diyl ratio gave [Ag({Ru(CO)2(η-C5H5)}2(η2-C≡C))2](BF4). The analogous Cu+ adduct [Cu({Ru(CO)2(η-C5H5)}2(η2-C≡C))2](PF6) is observed, along with the tricopper(I) adduct from the reaction of [{Ru(CO)2(η-C5H4R)}2(μ2-C≡C)] and [Cu(NCMe)4](PF6). A combination of factors appears to control the solid-state structures of these coinage metal adducts, with the anion found to be that which influences the packing to the greatest extent.

Dispersion, solvent and metal effects in the binding of gold cations to alkynyl ligands: implications for Au(I) catalysis.

The coordination modes of the [Au(PPh3)](+) cation to metal alkynyl complexes have been investigated. On addition to ruthenium, a vinylidene complex, [Ru(η(5)-C5H5)(PPh3)2([double bond, length as m-dash]C[double bond, length as m-dash]CPh{AuPPh3})](+), is obtained while addition to a gold(iii) compound gives di- and trinuclear gold complexes depending on the conditions employed. In the trinuclear species, a gold(i) cation is sandwiched between two gold(iii) alkynyl complexes, suggesting that coordination of multiple C-C triple bonds to gold is facile.

ChemInform Abstract: Group 8 Metal Alkynyl Complexes for Nonlinear Optics

AbstractReview: 96 refs.

DFT Calculation of Static First Hyperpolarizabilities and Linear Optical Properties of Metal Alkynyl Complexes

Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations are reported for a set of organometallic compounds for which the first hyperpolarizability values, β, have previously been determined in the laboratory. These calculations, which utilized a variety of density functionals and basis sets, address such aspects as the implications of molecular conformation and the extent of bond delocalization on the calculated β values. We also explore here the simplification of ligands for computational expedience and the influence of incorporation or exclusion of solvent corrections on β. The results of our study are likely to be of value in guiding subsequent efforts toward the reliable predictive calculation of the first hyperpolarizabilities and linear optical properties for organometallic compounds of interest to experimentalists.

Enhanced two-photon absorption cross-sections of zinc(II) tetraphenylporphyrins peripherally substituted with d6-metal alkynyl complexes

The syntheses of new Zn(II) tetraphenylporphyrin (ZnTPP) derivatives functionalized with electron-rich d6-transition metal alkynyl complexes at their periphery are reported. Z-scan measurements reveal remarkably large effective two-photon absorption (TPA) cross-sections in the visible range for these compounds.

Transition metal alkynyl complexes by transmetallation from Au(CCAr)(PPh3) (Ar = C6H5or C6H4Me-4)

Facile acetylide transfer reactions take place between gold(I) complexes Au(CCAr)(PPh3) (Ar = C6H5 or C6H4Me-4) and a variety of representative inorganic and organometallic complexes MXLn (M = metal, X = halide, Ln = supporting ligands) featuring metals from groups 8–11, to afford the corresponding metal–alkynyl complexes M(CCR)Ln in modest to good yield. Reaction products have been characterised by spectroscopic methods, and molecular structure determinations are reported for Fe(CCC6H4Me-4)(dppe)Cp, Ru(CCC6H4Me-4)(dppe)Cp*, Ru(CCC6F5)(η2-O2)(PPh3)Cp*, Ir(CCC6H4Me-4)(η2-O2)(CO)(PPh3)2, Ni(CCC6H4Me-4)(PPh3)Cp and trans-Pt(CCAr)2L2 (Ar = C6H5, L = PPh3; Ar = C6H4Me-4, L = PPh3, PMe3).

Synthesis, Optical Properties and Photophysics of Group 10–12 Transition Metal Complexes and Polymer Derived from a Central Tris(p-ethynylphenyl)amine Unit

A new series of luminescent group 10–12 metal alkynyl complexes and polyyne polymer containing a central tris(p-ethynylphenyl)amine bridging chromophore were prepared. The regiochemical structures of these triangular-shaped trinuclear compounds and polymer were studied by various spectroscopic and photophysical analyses. Upon photoexcitation, each of them emits an intense purple-blue fluorescence emission in the near UV region in dilute fluid solutions at room temperature. Harvesting of organic triplet emissions observed in the low-energy region harnessed through the strong heavy-atom effects of group 10–12 transition metals was examined and the results were compared among these three neighboring late transition metal elements. The influence of group 15 nitrogen-based heteroatom on the intersystem crossing rate and the spatial extent of the lowest singlet and triplet excitons was fully elucidated and a comparison was made to the nearest group 14 and 16 neighbors in the same row of the Periodic Table.

Some transition metal complexes derived from mono- and di-ethynyl perfluorobenzenes

Transition metal alkynyl complexes containing perfluoroaryl groups have been prepared directly from trimethylsilyl-protected mono- and di-ethynyl perfluoroarenes by simple desilylation/metallation reaction sequences. Reactions between Me(3)SiC[triple bond, length as m-dash]CC(6)F(5) and RuCl(dppe)Cp' [Cp' = Cp, Cp*] in the presence of KF in MeOH give the monoruthenium complexes Ru(C[triple bond, length as m-dash]CC(6)F(5))(dppe)Cp' [Cp' = Cp (); Cp* ()], which are related to the known compound Ru(C[triple bond, length as m-dash]CC(6)F(5))(PPh(3))(2)Cp (). Treatment of Me(3)SiC[triple bond, length as m-dash]CC(6)F(5) with Pt(2)(mu-dppm)(2)Cl(2) in the presence of NaOMe in MeOH gave the bis(alkynyl) complex Pt(2)(mu-dppm)(2)(C[triple bond, length as m-dash]CC(6)F(5))(2) (). The Pd(0)/Cu(i)-catalysed reactions between Au(C[triple bond, length as m-dash]CC(6)F(5))(PPh(3)) and Mo( identical withCBr)(CO)(2)Tp* [Tp* = hydridotris(3.5-dimethylpyrazoyl)borate], Co(3)(mu(3)-CBr)(mu-dppm)(CO)(7) or IC[triple bond, length as m-dash]CFc [Fc = (eta(5)-C(5)H(4))FeCp] afford Mo( identical withCC[triple bond, length as m-dash]CC(6)F(5))(CO)(2)Tp* (), Co(3)(mu(3)-CC[triple bond, length as m-dash]CC(6)F(5))(mu-dppm)(CO)(7) () and FcC[triple bond, length as m-dash]CC[triple bond, length as m-dash]CC(6)F(5) (), respectively. The diruthenium complexes 1,4-{Cp'(PP)RuC[triple bond, length as m-dash]C}(2)C(6)F(4) [(PP)Cp' = (PPh(3))(2)Cp (); (dppe)Cp (); (dppe)Cp* ()] are prepared from 1,4-(Me(3)SiC[triple bond, length as m-dash]C)(2)C(6)F(4) in a manner similar to that described for the monoruthenium complexes -. The non-fluorinated complexes 1,4-{Cp'(PP)RuC[triple bond, length as m-dash]C}(2)C(6)H(4) [(PP)Cp' = (PPh(3))(2)Cp (); (dppe)Cp (); (dppe)Cp* ()], prepared for comparison, are obtained from 1,4-(Me(3)SiC[triple bond, length as m-dash]C)(2)C(6)H(4). Spectro-electrochemical studies of the ruthenium aryl and arylene alkynyl complexes - and -, together with DFT-based computational studies on suitable model systems, indicate that perfluorination of the aromatic ring has little effect on the electronic structures of these compounds, and that the frontier orbitals have appreciable diethynylphenylene character. Molecular structure determinations are reported for the fluoroaromatic complexes , , , and .

Metal Alkynyl Complexes of Fluorene Derivatives

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Synthesis, spectroscopy, structures and photophysics of metal alkynyl complexes and polymers containing functionalized carbazole spacers

A new class of soluble and thermally stable group 10 platinum(II) poly-yne polymers functionalized with 9-arylcarbazole moiety trans-[-Pt(PBu 3) 2C CRC C-] n (R = 9-arylcarbazole-3,6-diyl; aryl = p-methoxyphenyl, p-chlorophenyl) were prepared in good yields by the polycondensation polymerization of trans-[PtCl 2(PBu 3) 2] with HC CRC CH under ambient conditions. The optical absorption and emission properties of these polymetallaynes were investigated and compared with their bimetallic molecular model complexes trans-[Pt(Ph)(PEt 3) 2C CRC CPt(Ph)(PEt 3) 2] as well as their group 11 gold(I) and group 12 mercury(II) neighbors [(PPh 3)AuC CRC CAu(PPh 3)] and [MeHgC CRC CHgMe]. The structures of all the compounds were confirmed by spectroscopic methods and by X-ray crystallography for selected model complexes. The influence of the heavy metal atom and the 9-aryl substituent of carbazole on the evolution of lowest electronic singlet and triplet excited states is critically characterized. It was shown that the organic-localized phosphorescence emission can be triggered readily by the heavy-atom effect of group 10–12 transition metals (viz., Pt, Au, and Hg) with the emission efficiency generally in the order Pt > Au > Hg. These carbazole-based organometallic materials possess high-energy triplet states of 2.68 eV or higher which do not vary much with the substituent of 9-aryl group.

Synthesis, structures and photoluminescence behavior of some group 10 metal alkynyl complexes derived from 3-( N-carbazolyl)-1-propyne

A new class of luminescent and thermally stable mononuclear group 10 platinum(II) and palladium(II) acetylides trans-[Pt(PR 3) 2(L) 2] (R = Bu, Et) and trans-[Pd(PBu 3) 2(L) 2] ( LH = 3-( N-carbazolyl)-1-propyne) have been successfully synthesized and characterized. The structural properties of these discrete metal complexes have been studied by X-ray crystallography. We report their optical absorption and photoluminescence spectra and interpret the results in terms of the nature of the metal center and the type of phosphines used. Our investigations indicate that they display heavy metal-enhanced phosphorescence bands at 77 K and we find that the platinum complexes afford more intense triplet emission than that for the palladium congener, consistent with the stronger heavy-atom effect of the third row element than the second row neighbor of the same group.

Alkynyl Compounds and Nonlinear Optics

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Metal Alkynyl σ Complexes: Synthesis and Materials

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Metal alkynyl sigma complexes: synthesis and materials.

Metal alkynyl complexes hold a fascination for synthetic chemists, structural chemists, and materials scientists alike. Harnessing the unique overlap of metal and carbon orbitals is a challenge that can be overcome in many ways and hence, there are many synthetic routes toward M-C=C-bond-forming reactions that utilize a wide variety of transition-metal and alkynyl reagents. Some methods can be widely applied, while others are specific to a particular metal or compound. The linear geometry of the alkynyl unit and its pi-unsaturated character have led to metal alkynyls becoming attractive building blocks for molecular wires and polymeric organometallic materials, which can possess interesting properties, such as optical nonlinearity, luminescence, liquid crystallinity, and electrical conductivity. A unique, multifaceted approach, often combining talents from all three of the above chemical disciplines, has served as a driving force behind the intense research into the development of metal alkynyl sigma complexes, the progress of which, particularly in the last ten years, is summarized in this review.

Organometallic complexes for nonlinear optics. 30.1 electrochromic linear and nonlinear optical properties of alkynylbis(diphosphine)ruthenium complexes.

A combination of cyclic voltammetry, UV-vis-NIR spectroelectrochemistry, time-dependent density functional theory (TD-DFT), and Z-scan measurements employing a modified optically transparent thin-layer electrochemical (OTTLE) cell has been used to identify and assign intense transitions of metal alkynyl complexes at technologically important wavelengths in the oxidized state and to utilize these transitions to demonstrate a facile electrochromic switching of optical nonlinearity. Cyclic voltammetric data for the ruthenium(II) complexes trans-[RuXY(dppe)(2)] [dppe = 1,2-bis(diphenylphosphino)ethane, X = Cl, Y = Cl (1), Ctbd1;CPh (2), 4-Ctbd1;CC(6)H(4)Ctbd1;CPh (3); X = Ctbd1;CPh, Y = Ctbd1;CPh (4), 4-Ctbd1;CC(6)H(4)Ctbd1;CPh (5)] show a quasi-reversible oxidation at 0.50-0.60 V (with respect to ferrocene/ferrocenium 0.56 V), which is assigned to the Ru(II/III) couple. The ruthenium(III) complex cations trans-[RuXY(dppe)(2)](+) were obtained by the in situ oxidation of complexes 1-5 using an OTTLE cell. The UV-vis-NIR optical spectra of 1(+)-5(+) contain a low-energy band in the near-IR region ( approximately 8000-16 000 cm(-)(1)), in contrast to 1-5, which are optically transparent at wavelengths < 22 000 cm(-)(1). TD-DFT calculations have been applied to model systems trans-[RuXY(PH(3))(4)] [X = Cl, Y = Cl, Ctbd1;CPh, or 4-Ctbd1;CC(6)H(4)Ctbd1;CPh; X = Ctbd1;CPh, Y = Ctbd1;CPh or 4-Ctbd1;CC(6)H(4)Ctbd1;CPh] to rationalize the optical spectra of 1-5 and 1(+)-5(+). The important low-energy bands in the electronic spectra of 1(+)-5(+) are assigned to the promotion of an electron from either a chloride p orbital or an ethynyl p orbital to the partially occupied HOMO. These absorption bands have been utilized to demonstrate a facile switching of cubic nonlinear optical (NLO) properties at 12 500 cm(-)(1) (corresponding to the wavelength of maximum transmission in biological materials such as tissue) using the OTTLE cell, the first electrochromic switching of molecular nonlinear refraction and absorption, and the first switching of optical nonlinearity using an electrochemical cell.

ChemInform Abstract: Molecular Design of Transition Metal Alkynyl Complexes as Building Blocks for Luminescent Metal‐Based Materials: Structural and Photophysical Aspects

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Molecular design of transition metal alkynyl complexes as building blocks for luminescent metal-based materials: structural and photophysical aspects.

In this Account, the design and successful isolation of a series of soluble di- and polynuclear alkynyl complexes of selected metals with d(8) and d(10) electronic configurations are described. These organometallic complexes are found to exhibit rich photophysical and photochemical properties that are unique to the presence of the alkynyl ligand. By a systematic variation of the nature of the ligands, the metal centers, and certain structural features, the photophysical properties could be readily varied and their spectroscopic origins elucidated. Some of these complexes have been shown to be ideal building blocks for the design of luminescent organometallic oligomers and metal-based functional materials.