Complexes Trans Research Articles

Synthesis, crystal structure and acidic properties in aqueous solution of phosphate ammine complexes of ruthenium nitrosyl

First examples of phosphate ammine complexes of ruthenium nitrosyl trans-[Ru(NO)(NH3)4(HxPO4)](NO3)x·(2−x)H2O (x=0, 1, 2) were obtained with good yields. Results of elemental analysis, X-ray, infrared, UV–Vis diffuse reflectance, and 31P NMR spectroscopies fit well with the formulas [Ru(NO)(NH3)4(PO4)]·2H2O (1), [Ru(NO)(NH3)4(HPO4)]NO3·H2O (2), and [Ru(NO)(NH3)4(H2PO4)](NO3)2 (3). In all the complexes, the phosphate group is in a trans-position to NO and is monodentate coordinated to ruthenium by one of the oxygen atoms. The pKa values 2.6 and 7.2 were calculated from potentiometric titration and 31P NMR for the reactions: trans-[Ru(NO)(NH3)4(H2PO4)]2++H2O⇆trans-[Ru(NO)(NH3)4(HPO4)]++H3O+ and trans-[Ru(NO)(NH3)4(HPO4)]++H2O⇆trans-[Ru(NO)(NH3)4(PO4)]+H3O+, respectively. The rate constant for the reaction trans-[Ru(NO)(NH3)4(H2O)]3++H2PO4−⇆trans-[Ru(NO)(NH3)4(H2PO4)]2++H2O was estimated as kobs=7×10−8s−1 at 70°C in a dilute solution of H3PO4 (∼5M).

Myristoylation Restricts Orientation of GRASP on Membranes and is Critical for Membrane Tethering

Mammalian Golgi Reassembly and Stacking Proteins (GRASP) self-interact to organize the Golgi apparatus into an elongated membrane network. Localized at the surfaces of apposed membranes by simultaneous binding of a Golgi-associated protein and insertion of an N-terminal myristate, GRASP proteins tether bilayers through trans complexes. We investigated the mechanism that drives trans pairing, given that unproductive cis interactions within a single membrane are otherwise favored. We established an assay that quantifies GRASP-dependent membrane tethering in vitro and used neutron reflection to determine the structure of the GRASP/membrane complex. In the assay, we substituted a C-terminal His-tag interaction with Ni2+-NTA-functionalized lipid for the normal protein-mediated membrane contact. Hence, fluorescent, NTA-labeled liposomes binds to NTA-doped sparsely-tethered lipid bilayer membranes (stBLMs [1]) only if the added GRASP construct formed trans complexes between the two. While Ni2+ chelation was sufficient to bind non-myristoylated GRASP to membranes, myristoylation increased GRASP tethering efficiency significantly. Neutron reflection showed that non-myristoylated GRASP exhibited no preferential orientation on stBLMs. In contrast, the tethering-competent myristoylated GRASP exhibited a specific orientation, deduced using the GRASP crystal structure [2]. From these neutron results, a model for surface-ligated GRASP could be derived, and docking studies suggest a structure of the membrane-tethering GRASP complex. These results indicate that myristoylation restricts the orientation of GRASP to favor trans complexes for membrane tethering.

Si-H bond activation at {(NHC)₂Ni⁰} leading to hydrido silyl and bis(silyl) complexes: a versatile tool for catalytic Si-H/D exchange, acceptorless dehydrogenative coupling of hydrosilanes, and hydrogenation of disilanes to hydrosilanes.

The unique reactivity of the nickel(0) complex [Ni2(iPr2Im)4(COD)] (1) (iPr2Im = 1,3-di-isopropyl-imidazolin-2-ylidene) towards hydrosilanes in stoichiometric and catalytic reactions is reported. A series of nickel hydrido silyl complexes cis-[Ni(iPr2Im)2(H)(SiH(n-1)R(4-n))] (n = 1, 2) and nickel bis(silyl) complexes cis-[Ni(iPr2Im)2(SiH(n-1)R(4-n))2] (n = 1, 2, 3) were synthesized by stoichiometric reactions of 1 with hydrosilanes H(n)SiR(4-n), and fully characterized by X-ray diffraction and spectroscopic methods. These hydrido silyl complexes are examples where the full oxidative addition step is hindered. They have, as a result of the remaining Si-H interactions, remarkably short Si-H distances and feature a unique dynamic behavior in solution. Cis-[Ni(iPr2Im)2(H)(SiMePh2)] (cis-5) shows in solution at room temperature a dynamic site exchange of the NHC ligands, H-D exchange with C6D6 to give the deuteride complex cis-[Ni(iPr2Im)2(D)(SiMePh2)] (cis-5-D), and at elevated temperatures an irreversible isomerization to trans-[Ni(iPr2Im)2(D)(SiMePh2)] (trans-5-D). Reactions with sterically less demanding silanes give cis-configured bis(silyl) complexes accompanied by the release of dihydrogen. These complexes display, similarly to the hydrido silyl complexes, interestingly short Si-Si distances. Complex 1 reacts with 4 eq. HSi(OEt)3, in contrast to all the other silanes used in this study, to give the trans-configured bis(silyl) complex trans-[Ni(iPr2Im)2Ni(Si(OEt)3)2] (trans-12). The addition of two equivalents of Ph2SiH2 to 1 results, at elevated temperatures, in the formation of the dinuclear complex [{(iPr2Im)Ni-μ(2)-(HSiPh2)}2] (6). This diamagnetic, formal Ni(I) complex exhibits a long Ni-Ni bond in the solid state, as established by X-ray diffraction. The capability of the electron rich {Ni(iPr2Im)2} complex fragment to activate Si-H bonds was applied catalytically in the deuteration of Et3Si-H to Et3Si-D employing C6D6 as a convenient deuterium source. Furthermore, we show that 1 serves as a catalyst for the acceptorless dehydrogenative coupling of Ph2SiH2 to the corresponding disilane Ph2HSi-SiHPh2 and trisilane Ph2HSi-Si(Ph)2-SiHPh2, and the coupling of PhSiH3 to give a mixture of cyclic and linear polysilanes with high polydispersity (M(w) = 1119; M(n) = 924; M(w)/M(n) = 1.2). The capability of 1 to catalyze the formal reverse reaction as well is demonstrated by the hydrogenation of disilanes. The hydrogenation of the disilanes Ph2MeSi-SiMePh2 and PhMe2Si-SiMe2Ph to the corresponding hydrosilanes Ph2MeSi-H and PhMe2Si-H, respectively, proceeds effectively in the presence of 1 under very mild conditions (room temperature, 1.8 bar H2 pressure).

Synthesis and electronic structure of the first cyaphide-alkynyl complexes

The novel complexes trans-[Ru(dppe)2(C≡CR)(C≡P)] (R = CO2Me, C6H4OMe), the first to incorporate cyaphide as part of a conjugated system, are obtained in facile manner. The electronic structure of these compounds is probed by X-ray, DFT and UV/Vis studies.

Crystal structure of the octahedral cluster complex trans-[{Re6S8}(pyz)4I2]·2pyz

The cluster complex of the composition trans-[{Re6S8}(pyz)4I2]· 2pyz (pyz is pyrazine) is obtained by the reaction of Cs4[{Re6S8}I6] with molten pyrazine. The compound crystallizes in the triclinic space group \(P\bar 1\) with the following unit cell parameters: a = 9.0562(7) A, b = 10.2502(7) A, c = 12.6783(9) A, α = 98.537(3)°, β = 107.573(2)°, γ = 106.943(3)°, V = 1036.6(1) A3, Z = 1, dcalc = 3.377 g/cm3. The crystal structure is built of trans-[{Re6S8}(pyz)4I2] cluster complexes and uncoordinated pyrazine molecules.

New mixed-ligand cyanohydroxo octahedral cluster complex trans-[Re6S8(CN)2(OH)4]4−, its luminescence properties and chemical reactivity

A new mixed-ligand anionic cluster complex trans-[Re6S8(CN)2(OH)4]4− has been synthesized and characterized by different physical methods. In addition, two representative reactions confirming the composition and structure of the anion have been carried out.

Guanidine platinum(II) complexes: synthesis, in vitro antitumor activity, and DNA interactions

The novel guanidine compounds trans-[Pt(NH2Me)2{NH=C(NHMe)NR}2](Cl)2 (R=NEt2 [7], NC5H10 [8]) (trans-7,8) were synthesized by the nucleophilic addition of methylamine to dialkylcyanamide ligands of the push–pull nitrile complexes trans-[PtCl2(RCN)2] (R=NEt2, NC5H10). In vitro cytotoxicity tests conducted for the entire series of the guanidine complexes, i.e. trans-7,8, the neutral cis- or trans-[PtCl2{NH=C(NH2)R}2] (cis-1–3 and trans-1–3) and the cationic cis- or trans-[Pt(NH3)2{NH=C(NH2)R}2](Cl)2 (cis-4–6 and trans-4–6) (R=NMe2 [1,4], NEt2 [2,5], NC5H10 [3,6]) in two human cancer cell lines, CH1 (ovarian carcinoma) and SW480 (colon cancer), confirmed that the cytotoxicity of several trans-configured (trans-3,6) complexes is higher than that of cis-congeners (cis-3,6). Cellular platinum levels were analyzed by inductively coupled plasma mass spectrometry upon treatment of SW480 cells, revealing a dependence of cellular accumulation on the geometrical isomerism and the steric hindrance of the variable substituent R on the guanidine ligand. DNA interactions of selected guanidine complexes were studied in order to find hints for the possible reasons for their different activities. Changes induced to the electrophoretic mobility of a dsDNA plasmid confirmed the potency of the guanidine complexes (e.g. trans-1,3,5,6 and cis-1,3,4) to significantly alter DNA secondary structure, indicating DNA as a possible critical target of these compounds.

Boryl‐Functionalized σ‐Alkynyl and Vinylidene Rhodium Complexes: Synthesis and Electronic Properties

The synthesis, reactivity, and properties of boryl-functionalized σ-alkynyl and vinylidene rhodium complexes such as trans-[RhCl(=C=CHBMes2)(PiPr3)2] and trans-[Rh(C≡CBMes2)(IMe)(PiPr3)2] are reported. An equilibrium was found to exist between rhodium vinylidene complexes and the corresponding hydrido σ-alkynyl complexes in solution. The complex trans-[Rh(C≡CBMes2)(IMe)(PiPr3)2] (IMe=1,3-dimethylimidazol-2-ylidene) was found to exhibit solvatochromism and can be quasireversibly oxidized and reduced electrochemically. Density functional calculations were performed to determine the reaction mechanism and to help rationalize the photophysical properties of trans-[Rh(C≡CBMes2)(IMe)(PiPr3)2].

Synthesis of trans bis-alkynyl complexes of Co(III) supported by a tetradentate macrocyclic amine: A spectroscopic, structural, and electrochemical analysis of π-interactions and electronic communication in the C[tbnd]C[sbnd]M[sbnd]C[tbnd]C structural unit

Alkynyl complexes of the type trans-[Co(cyclam)(CCR)2]OTf have been prepared and characterized by UV–Vis spectroscopy, 1H NMR, vibrational spectroscopy (infrared and Raman), and cyclic voltammetry. Where appropriate the data is compared to the corresponding Cr(III) and Rh(III) complexes. Though the arylalkynyl ligands have been shown to act as π-donors for the corresponding Cr(III) complexes, vibrational spectroscopy suggests that the π-interactions between the arylalkynyl ligands and Co(III) are quite weak, and that the more electron withdrawing trifluoropropynyl ligand likely behaves as a weak π-acceptor toward Co(III). X-ray crystal structures for trans-[Co(cyclam)(CCCF3)2]OTf and trans-[Cr(cyclam)(CCCF3)2]OTf are also reported and analysis of the MC and CC bond lengths are consistent with this understanding of the trifluoropropynyl ligand. Cyclic voltammetry of the trans-[Co(cyclam)(CCR)2]OTf complexes demonstrates that when R=C6H5 or p-C6H4CH3, the CoIII/II reduction wave is chemically irreversible. However, when R=p-C6H4CF3, p-C6H4CN, or CF3, the CoIII/II reduction wave is chemically reversible. This suggests that the more electron withdrawing alkynyl ligands become π-acceptors toward the reduced form of cobalt. Finally, the ferrocenyl capped trans-[M(cyclam)(CCFc)2]OTf complexes (where M=Co(III) and Rh(III)) were prepared and studied. Cyclic voltammetry shows only a single 2e− wave for the ferrocenyl termini, indicating little to no electronic communication through the organometallic backbone.

Synthesis of Heterodimetallic Complexes by Reaction of a Terminal Phosphido Pt Complex with Metal‐Based Nucleophiles and Electrophiles

AbstractThe complex trans‐[PtCl(PCy2)(PHCy2)2] (1) possesses a terminal phosphanido group (PCy2) and a chloride ligand, which render it a good candidate for the synthesis of phosphanido‐bridged heterodimetallic species (PHCy2)2Pt(μ‐PCy2)M–L by reaction either with carbonyl metalates, as metal‐based nucleophiles, or with metal‐based electrophiles. The heterodinuclear complexes [(PHCy2)2Pt(μ‐PCy2)Co(CO)3](Pt–Co) (2), [(PHCy2)2Pt(μ‐PCy2)Mo(CO)2Cp](Pt–Mo) (3), and [(PHCy2)2Pt(μ‐PCy2)W(CO)2Cp](Pt–W) (4) are obtained by reaction of 1 with the carbonyl metalates Na[Co(CO)4], Na[Mo(CO)3Cp] and Na[W(CO)3Cp], respectively. Although 2 is reluctant to react with carbon monoxide, 3 and 4 are promptly carbonylated under ambient conditions to afford mixtures of the cis and trans isomers of [(PHCy2)(CO)Pt(μ‐PCy2)M(CO)2Cp] (M = Mo or W), which interconvert through dissociation/reassociation of the CO ligand coordinated to the Pt centre. The reaction of 1 with AuCl(PPh3) leads to the formation of the trinuclear Pt2Au complexes cis‐ and trans‐[{Cl(PHCy2)2Pt(μ‐PCy2)}2Au]Cl (cis‐ and trans‐[8]Cl), in which a Au atom bridges two molecules of 1 through the originally terminal phosphanide ligands.

Hydrogenation of Dimethyl Carbonate to Methanol by trans-[Ru(H)2(PNN)(CO)] Catalysts: DFT Evidence for Ion-Pair-Mediated Metathesis Paths for C–OMe Bond Cleavage

Milstein and co-workers have reported that the pincer complexes trans-[Ru(H)2(PNN)(CO)] catalyze the unprecedented homogeneous hydrogenation of dimethyl carbonate to methanol. A mechanism for this reaction was proposed on the basis of (i) carbonyl group insertion into one of the Ru–H bonds to produce the six-coordinate trans-[Ru(OCH(OMe)2)(H)(PNN)(CO)] intermediate and (ii) a metal–ligand cooperative transformation, involving proton transfer from the phosphine arm of the PNN ligand to a methoxy group of the Ru-coordinated [OCH(OMe)2]− anion along with cleavage of a C–OMe bond, to produce methanol and an O-bound methyl formate complex of the dearomatized square-pyramidal form of the catalyst, [Ru(H)(PNN)(CO)]. We investigate herein the possibility of an alternative reaction pathway proceeding as (i) an outer-sphere hydride transfer from [Ru(H)2(PNN)(CO)] to the carbonyl of dimethyl carbonate to give an ion pair of the cationic metal fragment and the [OCH(OMe)2]− anion in which the C–H bond is facing the me...

Octadecylamine cobalt(III) dimethyl glyoximato complexes: synthesis, thermodynamics of micellization, steady-state photolysis and biological activities

A new class of surfactant–cobalt(III) complexes of the type trans-[Co(DH)2(OA)X], where DH = dimethylglyoxime, OA = octadecylamine, X = Cl−, Br−, I−, N3 −, NO2 −, SCN− or OA, were synthesized and characterized by physicochemical and spectroscopic methods. The critical micelle concentration (CMC) values of these surfactant–cobalt(III) complexes in ethanol solution were obtained by measuring absorption at ~250 nm. Specific conductivity data (at 303–313 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG m 0 , ΔH m 0 and ΔS m 0 ). Steady-state photolysis and cyclic voltammetry of the complexes were studied. The surfactant–cobalt(III) complexes were screened for their antibacterial and antifungal activities against various microorganisms.

The Synthesis and Structure of Hexakis(dimethylphenylphosphonite)ruthenium(II) bis[tetraphenylborate(-1)

Abstract. Treatment of the hydrazine salt [Ru(COD)(H2NNH2)4][BPh4]2 with excess of P(OMe)2Ph in acetone gave a homoleptic complex trans-[Ru{P(OMe)2Ph}6][BPh4]2, which was characterized by IR, 31P{1H}, 13C{1H}, and 1H NMR spectroscopy, elemental analysis, and X-ray crystallography. The ruthenium in the complex has distorted octahedral coordination arrangement and bonded to all the six P(OMe)2Ph molecules through the phosphorus atoms.

Mononuclear osmium(II) complexes bearing (S,S)-iPr-pybox and (R,R)-Ph-pybox ligands

The complexes trans-[OsCl2(L){(S,S)-iPr-pybox}] ((S,S)-iPr-pybox = 2,6-bis[4′-(S)-isopropyloxazolin-2′-yl]pyridine; L = CNBn (3), CNCy (4) and MeCN (7)) and trans-[OsCl2(L){(R,R)-Ph-pybox}] ((R,R)-Ph-pybox = 2,6-bis[4′-(R)-phenyloxazolin-2′-yl]pyridine, L = CNBn (5), CNCy (6) and MeCN (8)) have been stereoselectively synthesized from the complexes trans-[OsCl2(η2-C2H4)(R-pybox)] (R = (S,S)-iPr (1), (R,R)-Ph (2)), via substitution of ethylene, under reflux or microwave irradiation conditions. The complex trans-[OsCl2(η2-MeO2CCCCO2Me){(S,S)-iPr-pybox}] (9) has been analogous prepared from complex 1. The activation of terminal alkynes and alkynols by olefin complex 1, under toluene reflux conditions, has been achieved to give vinylidene trans-[OsCl2{CC(H)Ph}{(S,S)-iPr-pybox}] (10), allenylidene trans-[OsCl2(CCC(R)Ph){(S,S)-iPr-pybox}] (R = Ph (11), H (12)) and cyclic carbene complexes trans-[OsCl2(▪){(S,S)-iPr-pybox}] (13).

De novo generation of singlet oxygen and ammine ligands by photoactivation of a platinum anticancer complex.

Worth the excitement: Highly reactive oxygen and nitrogen species are generated by photoactivation of the anticancer platinum(IV) complex trans,trans,trans-[Pt(N3 )2 (OH)2 (MA)(Py)] (MA=methylamine, Py=pyridine). Singlet oxygen is formed from the hydroxido ligands and not from dissolved oxygen, and ammine ligands are products from the conversion of azido ligands to nitrenes. Both processes can induce oxidation of guanine.

Synthesis and Reactivity of New Bis(N-heterocyclic carbene) Iridium(I) Complexes

New complexes of the type trans-[IrCl(η(2)-COE)(NHC)2] (COE = cis-cyclooctene; NHC = N-heterocyclic carbene) have been prepared in one step from the reaction of ca. 4 equiv of NHC or [AgCl(NHC)] with [IrCl(η(2)-COE)2]2 in benzene. These new complexes have been characterized by techniques including NMR and IR spectroscopy, X-ray crystallography, and elemental analysis. Exposing trans-[IrCl(COE)(I(i)Pr(Me))2] to CO yielded trans-[IrCl(CO)(I(i)Pr(Me))2], which is the only bis(NHC) analogue of Vaska's complex trans-[IrCl(CO)(PPh3)2] known to date. The synthesis of trans-[Ir(CO)(I(i)Pr(Me))2(R)] (R = MeO, PhCC, OSiPh3, O2CPh) complexes has been achieved via deprotonation reactions involving the new hydroxide species trans-[Ir(OH)(CO)(I(i)Pr(Me))2].

Synthesis of Palladium and Platinum Complexes with an NH, NEt‐substituted Benzimidazolin‐2‐ylidene Ligand

Abstract The compound 2‐chloro‐N‐ethylbenzimidazole 1 was synthesized and was reacted with complexes of type [M(PPh3)4] (M = Pd, Pt) in the presence of NH4BF4 as proton source. This reaction leads via an oxidative addition to complexes of type [MCl(NH, NEt‐NHC)(PPh3)2]BF4 (M = Pd, [3]BF4; M = Pt, [4]BF4). In case of M = Pd, only compound trans‐[3]BF4 was obtained, while for M = Pt two isomeric platinum complexes cis‐[4]BF4 and trans‐[4]BF4 were obtained in a ratio of 78:22. The molecular structures of the square‐planar complexes trans‐[3](BF4) and cis‐[4]BF4 were determined by X‐ray diffraction.

Highly Efficient Deep‐Blue Emitters Based on cis and trans N‐Heterocyclic Carbene PtII Acetylide Complexes: Synthesis, Photophysical Properties, and Mechanistic Studies

We have synthesized cis and trans N-heterocyclic carbene (NHC) platinum(II) complexes bearing σ-alkynyl ancillary ligands, namely [Pt(dbim)2 (CCR)2 ] [DBIM=N,N'-didodecylbenzimidazoline-2-ylidene; R=C6 H4 F (4), C6 H5 (5), C6 H2 (OMe)3 (6), C4 H3 S (7), and C6 H4 CCC6 H5 (8)] and [Pt(ibim)2 (CCC6 H5 )2 ] (9) (ibim=N,N'-diisopropylbenzimidazoline-2-ylidene), starting from [Pt(cod)(CCR)2 ] (COD=cyclooctadiene) and 2 equivalents of [dbimH]Br ([ibimH]Br for complexes 9) in the presence of tBuOK and THF. Mechanistic investigations aimed at uncovering the cis to trans isomerization reaction have been performed on the representative cis complex 5 a [Pt(dbim)2 (CCC6 H5 )2 ] and revealed the isomerization to progress smoothly in good yield when 5 a was treated with catalytic amounts of [Pt(cod)(CCR)2 ] at 75 °C in THF or when 5 a was heated at 200 °C in the solid state under an inert atmosphere. Detailed examination of the reactions points to the possible involvement, in a catalytic fashion, of a solvent-stabilized Pt(II) dialkyne complex in the former case and a Pt(0) NHC complex in the latter case, for the transformation of the cis isomer to the corresponding trans complex. Thermal stability and the isomerization process in the solid state have been further investigated on the basis of TGA and DSC measurements. X-ray diffraction studies have been carried out to confirm the solid-state structures of 4 b, 5 a, 5 b, and 9 b. All of the synthesized dialkyne complexes 4-9 exhibit phosphorescence in solution, in the solid state at room temperature (RT), and also in frozen solvent glasses at 77 K. The emission wavelengths and quantum yields have been found to be highly tunable as a function of the alkynyl ligand. In particular, the trans isomer of complex 9 in a spin-coated film (10 wt % in poly(methyl methacrylate), PMMA) exhibits a high phosphorescence quantum yield of 80 %, which is the highest reported for Pt(II) -based deep-blue emitters. Experimental observations and time-dependent density functional theory (TD-DFT) calculations are strongly indicative of the emission being mainly governed by metal-perturbed interligand ((3) IL) charge transfer.

Synthesis, antiproliferative and mitochondrial impairment activities of bis-alkyl-amino transplatinum complexes

A convenient synthetic route and the characterization of complexes trans-[PtCl2(L)(PPh3)] (L=Et2NH (2), (PhCH2)2NH (3), (HOCH2CH2)2NH) (4) are reported. The antiproliferative activity was evaluated on three human tumor cell lines. The investigation on the mechanism of action highlighted for the most active complex 4 the capacity to affect mitochondrial functions. In particular, both the induction of the mitochondrial permeability transition phenomenon and an aspecific membrane damage occurred, depending on concentration.

Ferrocene and Tetrathiafulvalene Redox Interplay across a Bis-acetylide–Ruthenium Bridge

The interplay between two different peripheral electrophores, ferrocene (Fc) and tetrathiafulvalene (TTF), across a bis-acetylide ruthenium organometallic bridge has been studied within the novel complex trans-[Ru(C≡CMe3TTF)(C≡CFc)(dppe)2] (3) (HC≡CMe3TTF = 4-ethynyl-4′,5,5′-trimethyltetrathiafulvalene). A series of experimental data (electrochemistry, UV–visible spectroelectrochemistry, IR and EPR spectroscopy) and comparison with related complexes from the literature and with the properties of the Fc-C≡CMe3TTF species (4) have allowed the confident assignment of the electron transfer series in 3 and 4. Cyclic voltammetry experiments in dichloromethane in two supporting electrolytes ([NBu4][PF6] and [Na][B(C6H4(CF3)2)4]) have evidenced the extent of the electrostatic effects on the redox potentials in 3. The results of theoretical calculations (DFT) are consistent with these redox potential assignments but suggest some electronic coupling among the three coupled electrophores, the TTF, the Fc, and the Ru(II) center in 3•+ and 32+ and within Fc and TTF in 4•+. Taken together, these data show that the organometallic bis-acetylide ruthenium bridges mediate some appreciable electronic coupling between the two different ferrocene and tetrathiafulvalene electrophores.