Carbon-rich organometallics: synthesis and characterization of new ferrocenyl end-capped bis(butadiynyl) fluorene derivatives

A new series of ferrocenyl end-capped bis(butadiynyl) fluorene complexes [(η⁵-C₅H₅)Fe(η⁵-C₅H₄)CCCCRCCCC(η⁵-C₅H₄)Fe(η⁵-C₅H₅)] (R = fluoren-9-one-2,7-diyl, 1; 9,9-dihexylfluorene-2,7-diyl, 2; 9-ferrocenylmethylenefluorene-2,7-diyl, 3; 9-ferrocenylphenylmethylenefluorene-2,7-diyl, 4) have been synthesized in moderate yields by the oxidative coupling reactions of ethynylferrocene with half equivalents of the appropriate diethynylfluorene derivatives. All the new complexes have been characterized by FTIR, NMR and UV-vis spectroscopies and fast atom bombardment mass spectrometry. The molecular structures of selected molecules have been determined by X-ray crystallographic techniques. The electronic absorption and redox properties of these carbon-rich molecules were investigated and the data were compared with those for the corresponding 2,7-bis(ferrocenylethynyl)fluorene counterparts. Cyclic voltammetry indicates that the half-wave potential of the terminal ferrocenyl moieties becomes more anodic when the number of ethynyl units increases and when the 9-substituent of the central fluorene ring changes from an electron-donating group to an electron-deficient group.     

New ferrocenyl heterometallic complexes of 2,7-diethynylfluoren-9-one

A new series of rigid-rod alkynylferrocenyl precursors with central fluoren-9-one bridge, 2-bromo-7-(2-ferrocenylethynyl)fluoren-9-one (1b), 2-trimethylsilylethynyl-7-(2-ferrocenylethynyl)fluoren-9-one (2) and 2-ethynyl-7-(2-ferrocenylethynyl)fluoren-9-one (3), have been prepared in moderate to good yields. The ferrocenylacetylene complex 3 can provide a direct access to novel heterometallic complexes, trans-[(η⁵-C₅H₅)Fe(η⁵-C₅H₄)CCRCCPt(PEt₃)₂Ph] (4), trans-[(η⁵-C₅H₅)Fe(η⁵-C₅H₄)CCRCCPt(PBu₃)₂CCRCC(η⁵-C₅H₄)Fe(η⁵-C₅H₅)] (5), [(η⁵-C₅H₅)Fe(η⁵-C₅H₄)CCRCCAu(PPh₃)] (6) and [(η⁵-C₅H₅)Fe(η⁵-C₅H₄)CCRCCHgMe] (7) (R=fluoren-9-one-2,7-diyl), following the CuI-catalyzed dehydrohalogenation reactions with the appropriate metal chloride compounds. All the new complexes have been characterized by FTIR, ¹H-NMR and UV–vis spectroscopies and fast atom bombardment mass spectrometry. The solid state molecular structures of 3, 5, 6 and 7 have been established by X-ray crystallography. The redox chemistry of these mixed-metal species has been investigated by cyclic voltammetry and oxidation of the ferrocenyl moiety is facilitated by the presence of the heavy metal centre and increased conjugation in the chain through the ethynyl and fluorenone linkage units.     

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(PR₃)₂(L)₂] (R = Bu, Et) and trans-[Pd(PBu₃)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.     

Using ligand exchange reactions to control the coordination environment of Pt(II) acetylide complexes: applications to conjugated metallacyclynes

Ligand exchange of cis-bis(diphenylphosphino)ethylene (dppee) with trans-(Ph₃P)₂Pt(CCR)₂ easily generates the cis-complexes (dppee)Pt(CCR)₂ in 64-95% yield. This transformation is used to convert pyridine-containing macrocycle 7 to its cis-analogue 8 and the macrocyclic bipyridine analogue 10 to the unique macrocyclic ligand 11. X-ray structural characterization of trans-complexes 5a and 5b and cis-complexes 6a and 6b are reported, as is the structure of the strained macrocycle 8.     

Zur Darstellung und Reaktivität von Tetraalkylcyclobutadienplatin(II)-Komplexen [PtCl2(C4R4)L]

Preparation and Reactivity of Platinumcyclobutadiene Complexes [PtCl₂(C₄R₄)L] H[PtCl₃(C₄H₈)], prepared by reduction of H₂[PtCl₆] with n-butanol reacts with 2-pentyne to give equal amounts of the regioisomers [PtCl₂(C₄Et₂Me₂)] ( 3 a, 3 b ). An equimolar mixture of 2-butyne/3-hexyne reacts under the same conditions to give [PtCl₂(C₄Me₄)] ( 1 ), [PtCl₂(C₄Et₄)] ( 2 ) and [PtCl₂(C₄Et₂Me₂)] ( 3 a ) in a molar ratio 1:1.3:6.6. 1 and 2 react with ligands L (L = py a , p-tol b , PPh₃ c , AsPh₃ d , SbPh₃ e ) to give complexes of the type [PtCl₂(C₄R₄)L]. The complexes were characterized by microanalysis as well as by i.r., ¹H- and ¹³C-n.m.r. spectroscopy.     

Luminescent metal alkynyls - from simple molecules to molecular rods and materials

This review describes the design and synthesis of a number of luminescent transition metal alkynyls by this laboratory. The luminescence properties of the complexes have been studied and their emission origin elucidated. Some of these complexes have been shown to be ideal building blocks for the design and construction of luminescent molecular rods and materials, in which the luminescence properties can be readily tuned by changing the alkynyl ligands. Some of them also exhibited luminescence switching behaviour with the “ON-OFF” luminescence states modulated by redox processes, metal ion-binding or solvent composition.     

1-Methyl-4-ferrocenylmethyl-3,5-diphenylpyrazole: A versatile ligand for palladium(II) and platinum(II)

The syntheses and characterization of two novel ferrocene derivatives containing 3,5-diphenylpyrazole units of general formula [1-R-3,5-Ph₂-(C₃N₂)-CH₂-Fc] {Fc = (η⁵-C₅H₅)Fe(η⁵-C₅H₄) and R = H (2) or Me (3)} together with a study of their reactivity with palladium(II) and platinum(II) salts or complexes under different experimental conditions is described. These studies have allowed us to isolate and characterize trans-[Pd{1-Me-3,5-Ph₂-(C₃N₂)-CH₂-Fc]}₂Cl₂] (4a) and three different types of heterodimetallic complexes: cis-[M{1-Me-3,5-Ph₂-(C₃N₂)-CH₂-Fc]}Cl₂(dmso)] {M = Pd (5a) or Pt (5b)}, the cyclometallated products [M{κ²-C,N-[3-(C₆H₄)-1-Me-5-Ph-(C₃N₂)]-CH₂-Fc}Cl(L)] with L = PPh₃ and M = Pd (6a) or Pt (6b) or L = dmso and M = Pt (8b) and the trans-isomer of [Pt{1-Me-3,5-Ph₂-(C₃N₂)-CH₂-Fc]}Cl₂(dmso)] (7b). In compounds 4a, 5a, 5b and 7b, the ligand behaves as a neutral N-donor group; while in 6a, 6b and 8b it acts as a bidentate [C(sp²,phenyl),N(pyrazole)]⁻ group. A comparative study of the spectroscopic properties of the compounds, based on NMR, IR and UV-Visible experiments, is also reported.     

Structural Studies of Some Compounds Containing C2 Fragments Attached to Various Metal‐Ligand End‐Groups

The preparation, characterisation and single‐crystal XRD molecular structure determinations of four complexes containing –CC–ML_n end‐groups, namely Ru{C≡CFc′(I)}(dppe)Cp ( 1 ), the vinylidene [Os(=C=CH₂)(PPh₃)₂Cp]PF₆ ( 2 ), trans‐Pt(C≡CC₆H₄‐4‐C≡CPh){C≡CC₆H₄‐4‐C₂Ph[Co₂(μ‐dppm)(CO)₄]}(PPh₃)₂ ( 3 ), and C₆H₄{μ₃‐C₂[AuRu₃(CO)₉(PPh₃)]}₂‐1,4 ( 4 ) are reported. In these compounds a range of –CC– environments is found, extending from the σ‐bonded alkynyl group in 1 to examples where the C₂ unit interacts with either a proton (in vinylidene 2 ), by bridging a dicobalt carbonyl moiety (in 3 ) or the AuRu₃ cluster in 4 . Changes in geometry are rationalised by considering the various bonding modes.     

Oxidative addition of (PhSe)2 and (FcSe)2 to zerovalent palladium and platinum trialkylphosphine complexes (Fc = ferrocenyl, [Fe(η-C5H5)(η-C5H4)])

Room temperature reaction of [Pd₂(dba)₃]/PR₃ or [Pt(C₂H₄)(PR₃)₂] (dba = dibenzylideneacetone; R = Et, Bu) with the diselenides (R′Se)₂ (R′ = Ph, Fc) yielded the oxidative addition products trans-[M(SeR′)₂(PR₃)₂] (M = Pd, Pt). These have been characterised by multinuclear NMR and UV-Vis spectroscopy, mass spectrometry, and, in the cases of trans-[Pt(SePh)₂(PR₃)₂] (R = Et, Bu) and trans-[Pt(SeFc)₂(PBu₃)₂], also by X-ray crystallography.     

Synthese und Struktur der Nitrido‐Komplexe (PPh4)2[(O3Os≡N)2MCl2](M = Pd und Pt) und [{(Me2PhP)3Cl2Re≡N}2PdCl2]

Synthesis and Structure of the Nitrido Complexes (PPh₄)₂[(O₃Os≡N)₂ MCl₂] (M = Pd und Pt) and [{(Me₂PhP)₃Cl₂Re≡N}₂PdCl₂] The threenuclear complexes (PPh₄)₂[(O₃Os≡N)₂MCl₂] (M = Pd ( 1a ) and Pt ( 1b )) are obtained by the reaction of (PPh₄) [OsO₃N] with [MCl₂(NCC₆H₅)₂] (M = Pd and Pt) in form of orange red ( 1a ) or red brown ( 1b ) crystals. The compounds crystallize isotypically in the monoclinic space group P2₁/n with a = 1052.35(6), b = 1376.70(6), c = 1607.3(1) pm, β = 94.669(7)°, and Z = 2 for 1a and a = 1053.27(7), b = 1371.6(1), c = 1615.9(1) pm, β = 94.557(7)°, and Z = 2 for 1b . In the centrosymmetric complex anions [(O₃O≡N)₂MCl₂]^2— a linear MCl₂ moiety is connected in trans arrangement with two complexes [O₃Os≡N]^— via asymmetric nitrido bridges Os≡N‐M. For the M²⁺ cations such results a square‐planar coordination MCl₂N₂. The virtually linear nitrido bridges are characterized by distances Os‐N = 167.5 pm ( 1a ) and 164.2 pm ( 1b ) as well as Pd‐N = 196.2 pm and Pt‐N = 197.8 pm. The reaction of ReNCl₂(PMe₂Ph)₃ with PdCl₂(NCC₆H₅)₂ in CH₂Cl₂ yields red crystals of the heterometallic complex [{(Me₂PhP)₃Cl₂Re≡N}₂PdCl₂] ( 2 ). It crystallizes as 2 · 2 CH₂Cl₂ in the monoclinic space group C2/c with a = 2138.3(5); b = 1260.9(3); c = 2375.6(2) pm; β = 96.09(1)° and Z = 4. In the threenuclear complex [{(Me₂PhP)₃Cl₂Re≡N}₂PdCl₂] with the symmetry C_i the coordination of the Pd²⁺ cation of the central PdCl₂ unit is completed by two nitrido bridges Re≡N‐Pd to complexes (Me₂PhP)₃Cl₂Re≡N forming a square‐planar arrangement. The distances in the linear nitrido bridges are Re‐N = 170.2 pm and Pd‐N = 197.1 pm.     

Novel organometallic aromatic polyester based on ferrocene

<正>A novel polyester containing ferrocenyl was prepared by low-temperature interface polycondensation of 1,1'-ferrocenedicarboxylic acid chloride with 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one(DHPZ),which is a twisted non-coplanar heterocyclic bisphenol-like monomer.The newly generated polymer was evaluated based on characterization of its solubility,viscosity measurements,elemental analysis,FTIR spectroscopy,differential scanning calorimetric and thermogravimetric studies.     

Die Kristallstrukturen der Azido‐Platinate (AsPh4)2[Pt(N3)4] und (AsPh4)2[Pt(N3)6]

Crystal Structures of the Azido Platinates (AsPh₄)₂[Pt(N₃)₄] and (AsPh₄)₂[Pt(N₃)₆] The crystal structures of the two homoleptic azido platinates (AsPh₄)₂[Pt(N₃)₄] ( 1 ) and (AsPh₄)₂[Pt(N₃)₆] ( 2 ) were determined by X‐ray diffraction at single crystals. In 1 the [Pt(N₃)₄]^2– ions are without crystallographic site‐symmetry, and the platinum atoms show a planar surrounding. The [Pt(N₃)₆]^2– ions in 2 are centrosymmetric (C_i) with an octahedral surrounding at the platinum atoms. While 1 is highly explosive, 2 is of significantly greater stability. This behaviour is explained by the packing conditions. 1 : Space group P2₁/n, Z = 6, lattice dimensions at –80 °C: a = 1045.3(1), b = 1620.2(1), c = 4041.0(3) pm; β = 96.70(1)°; R₁ = 0.0654. 2 : Space group P1, Z = 1, lattice dimenstions at –80 °C: a = 1027.6(1), b = 1049.1(2), c = 1249.9(3) pm; α = 88.27(1)°, β = 74.13(1)°, γ = 67.90(1)°; R₁ = 0.0417.     

Synthesis, structures and photophysics of novel luminescent platinum–copper complexes

The novel hexanuclear platinum–copper complex [Pt₂Cu₄(C₆F₅)₄(CC^tBu)₄(acetone)₂] (1) and the polynuclear derivative [PtCu₂(C₆F₅)₂(CCPh)₂]_x (2), which crystallises in acetone as [Pt₂Cu₄(C₆F₅)₄(CCPh)₄(acetone)₄] (2)·(acetone)₄, have been prepared using [cis-Pt(C₆F₅)₂(THF)₂] and the corresponding copper–acetylide [Cu(CCR)]_x (molar ratio 1:2) as starting materials. Treatment of 1 and 2 with 2,2′-bipyridine (molar ratio Cu–bipy 1:1), afforded the new trinuclear derivatives [{cis-Pt(C₆F₅)₂(μ-CCR)₂}{Cu(bipy)}₂] (R=^tBu 3, Ph 4), in which the dianionic 3-platina-1,4-diyne acts as a didentate bridging ligand to two different cationic Cu(bipy) units through η²-side-on coordination of the alkynyl fragments. While similar treatment of 1 with dppe (Cu–dppe 1:1) yielded [{cis-Pt(C₆F₅)₂(μ-CC^tBu)₂}{Cu(dppe)}₂] (5), the analogous reaction of 2 with dppe afforded a mixture of complexes containing [Pt(C₆F₅)(CCPh)(dppe)] as the main platinum compound. The crystal structures of 1, 2·(acetone)₄, 3 and 4 and the luminescent behaviour of all complexes have been determined. A comparison of the photoluminescent spectra of 1 and 2 with those of the related platinum–silver species [PtAg₂(C₆F₅)₂(CCR)₂]_x and the monomeric [cis-Pt(C₆F₅)₂(CCR)₂]²⁻ suggests the presence of emitting states bearing a large cluster [PtM₂]_x-to-ligand (alkynide) charge transfer (CLCT).     

Short and efficient preparation of alkynyl selenides, sulfides and tellurides from terminal alkynes

Diphenyl diselenide reacts with terminal alkynes at room temperature in DMSO in the presence of catalytic amounts of copper iodide to give good to excellent yields of alkynyl phenyl selenides. The reaction occurs under neutral conditions and the solvent acts as the oxidant. Diphenyl disulfide and ditelluride undergo the analogous reaction, but require the presence of a weak inorganic base.     

Spectroscopic and biological properties of platinum complexes derived from 2-pyridyl Schiff bases

The reactions of a range of aromatic primary amines with pyridine-2-carboxaldehyde were reported, highlighting the effect of the substituents of the amine on the outcomes of the Schiff base reactions. The variant products of the Schiff base reactions were reacted with cis-[PtCl₂(DMSO)₂], generating platinum(II) complexes with PtCl₂(N^N) general formula. The ligands and platinum(II) complexes were identified and characterized by IR and NMR spectroscopic methods. Single crystal XRD offered structural confirmation for three of the organic compounds and two platinum complexes. The spectral, antimicrobial, DNA-binding and molecular docking of the platinum complexes were studied, highlighting the effect of the different functional group in the Schiff base ligands on their properties. In general, introducing the electron-withdrawing group nitro or acetyl in the 2-pyridyl Schiff base ligands, results in a red-shift in the absorption maxima of the platinum complex. In addition, the enhancement in the antimicrobial activities and the increase in the ct-DNA-binding affinity were also observed when the nitro or acetyl functional group is introduced to the Schiff base ligand in the platinum(II) complex.     

Improved approaches and structures of new ferrocenyl carbene complexes of chromium, tungsten, and molybdenum

Ferrocenyllithium reacts with M(CO)₆ (M = Cr, W, Mo) in THF to give, after alkylation at oxygen, the corresponding carbene complexes 3a-c in good yield. Complexes 3a,b were characterized by X-ray analysis. These complexes react with pentylamine to give the corresponding aminocarbene complexes 7a-c and with allylamine to give, in the case of chromium and tungsten, the corresponding and expected aminonocarbene complexes 8a,b, and for molybdenum, complex 9c in which the double bond is already coordinated to the metal. 8a,b could be converted in 9a,b in excellent yield. The structure of 9a could be confirmed by an X-ray analysis. Alkylations at nitrogen could be carried on complex 9c as well as on complexes 9a,b.     

Synthesis and characterisation of new platinum ethynyl dimers and polymers with pendant ferrocenyl groups

The square-planar platinum(II) complex trans-[(Ph₂FcP)₂PtCl₂] (1) (Fc=ferrocenyl), that is a metal-containing polymer precursor, has been synthesised and its single crystal structure determined. Using 1, new ferrocene-containing platinum ethynyl dimers trans-[(Ph₂FcP)₂Pt(CCR)₂] {R=SiMe₃ (2), C₆H₅ (3) and C₆H₄-p-NO₂ (4)} and a polymer [(Ph₂FcP)₂Pt(CCC₆H₂-p-(OC₈H₁₇)₂CC)]_n (5) have been formed by the reaction of the metal precursor with the appropriate mono- and bis-ethynyl ligands. Single crystal X-ray studies of 4 have shown it to exist as two different polymorphic forms, both having trans-geometry with respect to the ferrocenyl phosphines and ethynyl ligands. GPC measurements on the polymer show a high degree of polymerisation with an average molecular weight of ca. 88?000.     

Ge2H2 a π-ligand in organometallic chemistry

η² π-Complexes of Ge₂H₂ with the organometallic fragments V(PH₃)₂(I)(CO)₂, Cr(CO)₄, Co(PH₃)₂(Cl) and M(PH₃)₂ (M = Ni, Pd, Pt) have been studied at the B3LYP level using the SBKJC relativistic effective core potentials and their associated basis sets on metals and iodine, and the 6-31G(d) basis set on all other elements. The transition metal fragments of V, Cr, Co, Ni, Pd and Pt were chosen based on known alkyne compounds. All the complexes are local minima for both the HGeGeH and GeGeH₂ isomers of the Ge₂H₂ ligand. The complexes containing GeGeH₂ isomer as a ligand are lower in energy than those with the HGeGeH ligand (except in the V complex in which the difference is only 1.0 kcal/mol). There is a net charge transfer from ligand to metal in complexes V-Co and from metal to ligand in late transition metal complexes (Ni-Pt).     

Zur Struktur und Konstitution von Dichloro(tetraalkylcyclobutadien)platin(II)-Komplexen

Structure and Constitution of Dichloro(tetraalkylcyclobutadiene)platinum(II) Complexes Hexachloroplatinic acid reacts in n-butanol with alkylsubstituted acetylenes RC≡CR (R = Me, Et) to give [PtCl₂(C₄R₄)] (R = Me ( 1 ), R = Et ( 2 )). The X-ray structure analysis of 1 (C2/m; a = 1 370.3(2), b = 1 128.3(1), c = 691.21(7) pm, β = 96.10(1)α; Z = 4) shows that 1 is monomeric and not dimeric as was described in the literature. Furthermore, 1 and 2 were extensively studied by i.r., Raman, and n.m.r. spectroscopical investigations.     

Metallacarboranes and triple-decker complexes with the (C4Me4)Pt fragment

Complex Cp∗PtCl₂ (Cp∗ = η-C₄Me₄) reacts with the carborane anions [7,8-C₂B₉H₁₁]²⁻ and [9-SMe₂-7,8-C₂B₉H₁₀]⁻ giving platinacarboranes Cp∗Pt(η-7,8-C₂B₉H₁₁) (1) and [Cp∗Pt(η-9-SMe₂-7,8-C₂B₉H₁₀)]⁺ (2), respectively. Reactions of the [Cp∗Pt]²⁺ fragment (as a labile nitromethane solvate) with the sandwich compounds Cp∗Fe(η-C₅H₃Me₂BMe) and Cp∗Rh(η⁵-C₄H₄BPh) afford the triple-decker cations [Cp∗Pt(μ-η:η-C₅H₃Me₂BMe)FeCp∗]²⁺ (3) and [Cp∗Pt(μ-η⁵:η⁵-C₄H₄BPh)RhCp∗]²⁺ (4) with bridging boratabenzene and borole ligands. The structures of 1 and 3(CF₃SO₃)₂ were determined by X-ray diffraction.