Terpyridyl Groups Research Articles

Enhanced Thermally Activated Delayed Fluorescence by Sole Coordination: From an Organic Molecule to Its Zinc Complex.

A BPAPTPyC organic molecule containing a sandwich structural chromophore is designed and synthesized to produce blue thermally activated delayed fluorescence (TADF). The chromophore is composed of two di(4-tert-butylphenyl)amino donors and one inserted terpyridyl acceptor hitched at positions 1, 8, and 9 of a single carbazole via the p-phenylene group, in which the multiple space π-π interactions between the donor and acceptor enable the molecule to possess the TADF feature with a high energy emission at 470 nm but a low photoluminescence quantum yield (PLQY) and a small proportion of the delayed component. In contrast, the corresponding Zn(BPAPTPyC)Cl2 complex has a high PLQY and a short lifetime with a red-shifted emission due to the enhanced rigidity and electron accepting ability of the terpyridyl group from coordination. A solution-processed organic light-emitting diode (OLED) based on the complex achieves a maximum external quantum efficiency (EQE) of 17.9% with an emission peak at 585 nm, while an OLED of the organic molecule produces blue emission with a maximum EQE of 2.7%.

Cobalt-Centered Supramolecular Nanoensemble for Regulated Aerobic Oxidation of Alcohols and "One-Pot" Synthesis of Quinazolin-4(3H)-ones.

The supramolecular assemblies of the donor-acceptor (D-A) system Im-Tpy, having phenanthro[9,10-d]imidazole as the donor and terpyridyl group as the acceptor unit, have been developed, which serve as supramolecular host to stabilize Co(II) in its nanoform. The as-prepared supramolecular nanoensemble Im-Tpy@Co in DMSO:water (7:3) shows high thermal stability and photostability. Even in the case of solvent mismatch, i.e., on dilution with cosolvent THF/DMSO, insignificant changes were observed in the size/morphology of the nanoensemble. The as-prepared Im-Tpy@Co nanoensemble in low catalytic loading (0.1 mol % of Co) catalyzes the oxidation of a wide variety of alcohols to aromatic aldehydes/ketones using visible light radiations as the source of energy without the need of any additive at room temperature. In comparison to already reported systems, the Im-Tpy@Co nanoensemble exhibits high turnover numbers (TONs) and turnover frequencies (TOFs). The practical application of the catalytic system has also been demonstrated in the gram-scale synthesis of 4-chlorobenzaldehyde. The Im-Tpy@Co nanoensemble exhibits recyclability up to four catalytic cycles with insignificant leaching and morphological changes. The present study also demonstrates the catalytic activity of the Im-Tpy@Co nanoensemble in "one-pot" synthesis of quinazolin-4(3H)-ones from 2-aminobenzamide and primary alcohols with better efficiency in comparison to other transition-metal-based catalytic systems.

Dielectric and energy storage performance of polymers bearing terpyridyl group and metal ion complex by ring-opening metathesis polymerization

Block copolymers with terpyridyl-metal ion pendant were prepared by ring-opening metathesis polymerization, and self-assembled into nanostructure in the selective solvent. The dielectric properties of polymers could be well regulated by adjusting the content of metal ions. The dielectric constant of Ru(II)-contained block copolymer reached high value of 32.5, the dielectric loss was lowered to 0.01 in the frequency range of 100 Hz to 1 MHz, and the energy storage density was up to 5.2 J·cm−3 at the electric field strength of 325 mV·m−1 accompanied with the charge-discharge efficiency of 83.3%, which was attributed to the electronic polarization and interface polarization from the metal ions and nanostructure. Therefore, the introduction of metal ion into the side chain was an effective way to enhance the dielectric and energy storage properties of polymers.

Terpyridyl-based triphenylamine derivatives with aggregation-induced emission characteristics for selective detection of Zn2+, Cd2+ and CN− ions and application in cell imaging

Two terpyridyl triphenylamine derivative luminogens (DTPy-TPA and TPy-TPA) with aggregation-induced emission (AIE) characteristics were designed and synthesized. The number of terpyridyl units of these two compounds has a remarkable effect on the responses towards metal ions. DTPy-TPA with two terpyridyl groups on both sides displayed multi-response to Zn2+ and Cd2+ in THF solution along with distinct absorption and emission spectral changes, and obvious naked-eye color changes. However, TPy-TPA with one terpyridyl phenyl group didn't work. This should be resulted from the formation of supramolecular polymers or oligomers for DTPy-TPA to restrict the intramolecular motions, but dimers for TPy-TPA. Moreover, both of these two compounds in H2O/THF (9:1, v:v) solution could selectively and sensitively detect CN− with distinct fluorescence quenching, which was attributed to the nucleophilic addition of CN− to the α-position of the dicyanovinyl group and thus the free rotation of phenyl groups on TPA. The sensing mechanism of DTPy-TPA or TPy-TPA with CN− was confirmed by 1H NMR titration and Job's plot. Finally, based on their excellent photophysical properties, these two probes were successfully employed to detect CN− in living HEK293 cells using fluorescence bioimaging.

Self-healable, Eu3+-based polymeric gels containing terpyridyl groups with tunable luminescence based on ion recognition

Novel luminescent materials that change their emission colors in responding to external stimuli have attracted increasing attentions in the past decades. Herein, we report the preparation of a novel kind of Eu3+-based polymeric organogel with three networks. With dynamic coordination interactions, the organogel shows fast self-healing and adjustable fluorescent emission properties in the presence of different metal ions via coordination interaction competition effect. Dynamic coordination interaction also endows the gel with multiple stimuli-responsive properties such as water, base and acid. The multistimuli responsive fluorochromic organogel demonstrates a new way of preparing optical materials and bio-relevant sensors.

Synthesis, crystallographic and spectral studies of homochiral cobalt(II) and nickel(II) complexes of a new terpyridylaminoacid ligand

Based on a chiral terpyridylaminoacid ligand, a series of homochiral Co(II) and Ni(II) complexes, namely, [Co(H2L)(HL)]·Cl·(PF6)2·2H2O (1), [Ni(H2L)(HL)]·Cl·(PF6)2 (2), [Co2(L)2(CH3OH)(H2O)]·(PF6)2·CH3OH (3), [Ni2(L)2(CH3OH)2]·(PF6)2·2CH3OH (4), [Co2(L)2(N3)2]·3H2O (5), and [Ni2(L)2(SCN)2]·4H2O (6) have been successfully synthesized and characterized by elemental analysis, TGA, spectroscopic methods (IR, CD and electronic absorption spectra) and single-crystal X-ray diffraction structural analysis (HL = (S)-2-((4-([2,2':6′,2″-terpyridin]-4′-yl)benzyl)amino)-4-methylpentanoic acid). In the acidic reaction conditions, one protonated (H2L)+ and one zwitterionic HL only used their terpyridyl groups to chelate one metal ion Co(II) or Ni(II), forming chiral mononuclear cationic complexes 1 or 2. But in the basic and hydro(solvo)thermal reaction conditions, deprotonated ligands (L)‒ acting as bridges used their terpyridyl and amino acid groups to link with two Co(II) or Ni(II) ions, fabricating chiral dinuclear metallocyclic complexes 3–6. Those chiral mononuclear and dinuclear complexes whose chirality originates in the homochiral ligand HL further self-assemble into higher-dimensional homochiral supramolecular frameworks through intermolecular hydrogen-bonding and π···π interactions. Notably, the coordination mode, hydrogen-bonding site, and existence form of HL ligand can be controlled by the protonation of its amino group, and the architectural diversity of those supramolecular frameworks is adjusted by pH and counter anions. Very interestingly, the 3D porous supramolecular frameworks built up from the huge chiral mononuclear cationic complexes 1 and 2 have novel helical layers only formed through every right-handed helical chain intertwining with two adjacent same helical chains, and the 2D supramolecular helicate 5 consists of two types of left-handed helical chains.

An ultrasound triggered gelation approach to selectively solvatochromic sensors

Development of solvatochromic sensor that is responsive to solvents with high selectivity is still a challenging work. Here, we present the first example that an organic molecular aggregate system can be developed as a visual and reversible sensor for selective discrimination of dimethyl sulphoxide (DMSO) from common organic solvents, through ultrasound triggered chromic effect. In this work, two novel compounds T1 and T2 are designed and characterized by combining terpyridyl group as an electron donor and naphthalimide segment as an electron acceptor with amide bond of different alkyl chains. These compounds can gel in a series of organic solvents just at room temperature when subjected to ultrasound. However, transparent red sonogels are only observed in DMSO even though their DMSO solutions are yellow, whereas in other organic solvents, gels have yellow color. Therefore, the ultrasound triggered aggregate system can be developed for selective discrimination of DMSO from common organic solvents by gel array. Moreover, a red-to-yellow colorimetric transition takes place when increasing amount of water is added to the gel, endowing the water detection capability of gel in DMSO. A visual sensor array of these gels is thus created to allow identification of water content in DMSO from 0.5 to 10% by naked eye and fluorescent emission changes.

Coordination‐Driven Terpyridyl Phosphine Pd(II) Gels

AbstractIncorporation of phosphine‐Pd catalytic centers in gel network is an important strategy to develop highly active catalysts. In this contribution we show that catalytically active phosphine‐Pd(II) gels can be readily obtained via reaction of rigid bridging terpyridyl phosphines and Pd(II). The terpyridyl phosphines, Py2P2 and Py2P, contain one 4,2′:6′,4′ ′‐terpyridyl group and two/one diphenylphosphino groups. Reactions of Py2P2/Py2P and Pd(II) in CHCl3‐MeOH afforded the corresponding phosphine‐Pd(II) gels at room temperature or at elevated temperature (40°C). The gelation is driven by formation of metal‐organic coordination. Mild heating is important in triggering the formation of Py2P‐Pd(II) gel. The gels have a coherent, rigid spongy porous network of continuous nanometer‐sized particles. The phosphine‐Pd(II) gels showed high activity in the Suzuki‐Miyaura reactions of aryl bromides under ambient conditions and could be recycled and reused.

Off–on–off pH luminescence switching and DNA binding properties of a free terpyridine-appended ruthenium complex

A ruthenium(II) complex [Ru(bpy)2(HL1)](ClO4)2·3H2O {bpy=2,2′-bipyridine and HL1=2-(2,6-di(pyridin-2-yl)pyridin-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline}, denoted as RuHL1, was synthesized and characterized by elemental analysis, proton nuclear magnetic resonance spectroscopy, and mass spectrometry. The pH effects on the UV–visible (UV–vis) absorption and emission spectra and the luminescence lifetimes of RuHL1 have been studied, and their ground- and excited-state acid ionization constants were derived. The complex was found to exhibit pH-induced “off–on–off” luminescence switching properties via protonation/deprotonation of the grafted imidazole and terpyridyl groups. A pH-induced emission on–off intensity ratio of 166 was observed as pH was increased from 2.00 to 5.44, which is one of the largest values observed among imidazole-containing Ru(II) complex-based acidic-pH-induced pH luminescence switches. RuHL1 also strongly binds to calf thymus DNA in mixed binding modes involving classic intercalation and partial intercalation, as determined by UV–vis absorption and emission spectrophotometric DNA titration, ethidium bromide displacement, DNA denaturation and DNA viscosity measurements.

Linker Rectifiers for Covalent Attachment of Transition‐Metal Catalysts to Metal‐Oxide Surfaces

Linkers that favor rectification of interfacial electron transfer are likely to be required for efficient photo-driven catalysis of multi-electron reactions at electrode surfaces. Design principles are discussed, together with the synthesis and characterization of a specific pair of molecular linkers, related by inversion of the direction of an amide bond in the heart of the molecule. The linkers have a terpyridyl group that can covalently bind Mn as in a well-known water oxidation catalyst and an acetylacetonate group that allows attachment to TiO2 surfaces. The appropriate choice of the sense of the amide linkage yields directionality of interfacial electron transfer, essential to enhance electron injection and slow back-electron transfer. Support comes from electron paramagnetic resonance and terahertz spectroscopic measurements, as well as computational modeling characterizing the asymmetry of electron transfer properties.

Synthesis, characterization, and ion responsive properties of hyperbranched oligofluorene using carbazole as a branching core

We report the synthesis of a triphenylamine-based hyperbranched oligofluorene (HPFT) containing a pendant terpyridine group by using Suzuki coupling polymerization. The effects of the hyperbranched structure on the photophysical, electrochemical, and chemosensory properties of HPFT are compared with those for linear oligofluorene (PFT). Both PFT and HPFT exhibit favorable thermal stabilities, with thermal decomposition temperatures greater than 406.7°C. Increasing the polarity of organic solvents produces bathochromic shifts in the PL spectra of PFT and HPFT. Substitution with triphenylamine groups raised the ionization potentials of both PFT and HPFT, as confirmed by the highest occupied molecular orbital level (HOMO) of 5.10–5.22eV below vacuum relative to PF without triphenylamine substitution (5.65eV). PFT and HPFT containing pendant terpyridyl groups exhibit increased sensitivity to the Ni2+ ion, with Stern–Volmer constants (Ksv) of 1.86×104M−1 and 5.01×104M−1, respectively. Our results suggest that HPFT is a promising material for chemosensory applications.

Interpretation of experimental N K NEXAFS of azide, 1,2,3-triazole and terpyridyl groups by DFT spectrum simulations

Experimental N K-edge NEXAFS data of surface immobilized azide, 1,2,3-triazole and terpyridyl groups are interpreted with the help of DFT spectrum simulations. Assignments of π* resonances in experimental N K-edge NEXAFS spectra to nitrogen atoms within these functional groups have been made. The azide was immobilized on gold as the head group of a thiol SAM, 1,2,3-triazole was formed on this SAM by click reaction and terpyridyl groups were introduced as substituents of the acetylene used for the click reaction. For azide-terminated molecules, DFT spectrum simulations are found to be useful to find measurement conditions delivering experimental N K-edge NEXAFS data with negligible X-ray damage. The 1,2,3-triazole group is found to be rather stable under X-ray irradiation.

Intermixed Terpyridine-Functionalized Monolayers on Gold: Nonlinear Relationship between Terpyridyl Density and Metal Ion Coordination Properties

Aiming at the functionalization of surfaces with terpyridine anchors for the coordinative deposition of additional layers, mixed self-assembled monolayers (SAMs) were prepared from binary solutions of 12-(2,2':6',2″-terpyridine-4'-yl)dodecane-1-thiol (TDT) and 1-decanethiol (DT). The SAMs and the order of the constituting molecules were analyzed by X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure spectroscopy (NEXAFS), and time-of-flight-secondary ion mass spectrometry (ToF-SIMS). The composition of the (TDT/DT)-SAMs and with it the surface density of terpyridyl groups correlates linearly with the relative concentrations of the two compounds in the solution used for depositing them. In marked contrast, the amount of terpyridine-coordinated Pd(II) ions significantly deviates from this trend with an optimum at a 1:3 ratio of TDT/DT. This indicates a major fraction of the terpyridines in TDT-rich SAMs not to be accessible for Pd(II) ion coordination. In agreement, NEXAFS spectroscopy reveals the alkyl backbones in TDT-rich SAMs not to be ordered, while they are preferentially upright oriented in the optimal 1:3-(TDT/DT)-SAMs. We interpret this in terms of terpyridine backfolding in TDT-rich SAMs, while they are located in accessible positions on top of the SAM in the 1:3-(TDT/DT)-SAM. While the alkyl backbones in the 1:3-(TDT/DT)-SAM are ordered, NEXAFS spectroscopy shows the terpyridyl groups not to have a preferential orientation in this SAM and thus retain enough flexibility to adjust to molecules that are deposited on top of the mixed SAM. In conclusion, the novel SAM does not undergo phase separation and consists predominantly of intermixed phases with adjustable surface density of quite flexible terpyridine anchor groups. The terpyridine-Pd(II) anchors are not only available for a future deposition of the next layer, but the metal ions also represent a sensitive probe for the accessibility of the terpyridyl groups.

A New Actinide Bis(Ketimide) Platform for the Construction of Multimetallic Complexes: Synthesis and Crystal Structure of (C5Me5)2Th[-N=C(C6H5)(2,2′:6′,2″-terpyridine)

The title compound (C5Me5)2Th[-N=C(Ph)(tpy)]2 (1) (Ph=C6H5, tpy=2,2′:6′,2″-terpyridine) was synthesized and characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. This system represents the first example of an actinide complex featuring ketimide ligands with both a phenyl group and a terpyridyl group. The complex crystallizes in the monoclinic space group P21/c with unit cell parameters a = 10.7037(6) A, b = 32.0735(16) A, c = 34.6506(18) A, β = 90.127(3)°, V = 11895.7(11) A3, Z = 8, D calc = 1.406 Mg/m3. The thorium(IV) complex adopts a pseudo-tetrahedral geometry, with the two ketimide ligands occupying the plane bisecting the metallocene unit. Structural comparisons of the title complex are made with related metallocene thorium(IV) bis(ketimide) derivatives. This report describes the synthesis of (C5Me5)2Th[-N=C(Ph)(tpy)]2 (Ph=C6H5, tpy=2,2′:6′,2″-terpyridine) and its characterization by NMR spectroscopy, elemental analysis, and X-ray crystallography.

Bis{μ-4′-[4-(quinolin-8-yloxymethyl)phenyl]-2,2′:6′,2′′-terpyridine}disilver(I) bis(perchlorate) dimethylformamide disolvate

In the binuclear title complex, [Ag2(C31H22N4O)2](ClO4)2·2C3H7NO, the AgI atom is penta­coordinated by three N atoms from the tridentate chelating terpyridyl group and by one N atom and one O atom from the quinolin-8-yl­oxy group in a distorted square-pyramidal geometry with the O atom at the apical position. The centrosymmetric complex cation involves intra­molecular π–π stacking inter­actions [centroid–centroid distance = 3.862 (4) Å] between the central pyridine and benzene rings. In the crystal structure, inter­molecular C—H⋯O hydrogen bonds result in the formation of a supra­molecular network.

Ruthenium(II) Complexes with Improved Photophysical Properties Based on Planar 4‘-(2-Pyrimidinyl)-2,2‘:6‘,2‘ ‘-terpyridine Ligands

A series of new tridentate polypyridine ligands, made of terpyridine chelating subunits connected to various substituted 2-pyrimidinyl groups, and their homoleptic and heteroleptic Ru(II) complexes have been prepared and characterized. The new metal complexes have general formulas [(R-pm-tpy)Ru(tpy)]2+ and [Ru(tpy-pm-R)2]2+ (tpy = 2,2':6',2' '-terpyridine; R-pm-tpy = 4'-(2-pyrimidinyl)-2,2':6',2' '-terpyridine with R = H, methyl, phenyl, perfluorophenyl, chloride, and cyanide). Two of the new metal complexes have also been characterized by X-ray analysis. In all the R-pm-tpy ligands, the pyrimidinyl and terpyridyl groups are coplanar, allowing an extended delocalization of acceptor orbital of the metal-to-ligand charge-transfer (MLCT) excited state. The absorption spectra, redox behavior, and luminescence properties of the new Ru(II) complexes have been investigated. In particular, the photophysical properties of these species are significantly better compared to those of [Ru(tpy)2]2+ and well comparable with those of the best emitters of Ru(II) polypyridine family containing tridentate ligands. Reasons for the improved photophysical properties lie at the same time in an enhanced MLCT-MC (MC = metal centered) energy gap and in a reduced difference between the minima of the excited and ground states potential energy surfaces. The enhanced MLCT-MC energy gap leads to diminished efficiency of the thermally activated pathway for the radiationless process, whereas the similarity in ground and excited-state geometries causes reduced Franck Condon factors for the direct radiationless decay from the MLCT state to the ground state of the new complexes in comparison with [Ru(tpy)2]2+ and similar species.

Synthetic strategies for preparing BEDT-TTF derivatives functionalised with metal ion binding groups

The syntheses of BEDT-TTF (ET) derivatives with potential metal ion binding pyridyl, bipyridyl and terpyridyl groups is achieved either by stepwise construction of the organosulfur core or via reactions of hydroxymethyl-ET for which a cheap and efficient four step route is reported. The tosylate of hydroxymethyl-ET, reported for the first time, undergoes nucleophilic substitutions with pyridyl, bipyridyl- and terpyridyl-thiolates to give new donors. The X-ray crystal structures of two substituted ET derivatives show considerable deviation of the organosulfur donor system from planarity by bending about the short molecular axis of the ET group.

Synthesis of the terpyridyl pendant-arm azamacrocycle 4′-( p-1,4,7-triazacyclonon-1-ylmethylphenyl)-2,2′∶6′,2″-terpyridine (L) and complexes of L with copper(II) and nickel(II). Crystal structure of [Cu(HL)(H2O)2][PF6

The azamacrocyclic ligand 4′-(p-1,4,7-triazacyclonon-1-ylmethylphenyl)-2,2′∶6′,2′′-terpyridine (L) has been prepared, and some of the complexes it forms with hydrated copper(II) and nickel(II) have been isolated as the [PF6]− salts. X-Ray crystallography has been used to determine the solid state structure of the distorted trigonal bipyramidal complex [Cu(HL)(H2O)2][PF6]3, in which the copper(II) is co-ordinated to the terpyridyl group and the azamacrocycle is monoprotonated and non-co-ordinating. A bis(2,2′∶6′,2′′-terpyridine)nickel(II) complex, [Ni(H2L2)2][PF6]6 has also been isolated, in which each azamacrocycle is diprotonated.

Stepwise synthetic strategy for the preparation of trinuclear complexes of bis(terpyridyl) bridging ligands containing aza-crown macrocyclic spacer groups

A synthetic strategy has been devised for the preparation of the mononuclear complex [Ru(tpy)(L2)][PF6]2 (where L2 is a bridging ligand containing two chelating 2,2′∶6′,2″-terpyridyl fragments attached via tolyl spacers to the N atoms of a 1,10-diaza-18-crown-6 macrocycle), which avoids the separation of a statistical mixture of mono- and di-nuclear complexes which would arise from normal synthetic methods. Reaction of 1,10-diaza-18-crown-6 with one equivalent of 4′-[4-(bromomethyl)phenyl]terpyridine afforded L1, in which there is one terpyridyl group pendant from the macrocycle, and the second NH site of the macrocycle is not alkylated. Reaction of L1 with [Ru(tpy)Cl3] gave mononuclear [Ru(tpy)(L1)][PF6]2. Subsequent reaction of this with a second equivalent of 4′-[4-(bromomethyl)phenyl]terpyridine resulted in attachment of the second (vacant) terpyridyl chelating site by alkylation of the remaining secondary amine group in the macrocycle to give [Ru(tpy)(L2)][PF6]2. Assembly of two of these mononuclear ‘complex ligands’ around first-row transition-metal dications M2+ (M = Fe or Ni) afforded in high yield the linear trinuclear Ru–M–Ru complexes [{(tpy)Ru(L2)}2M][PF6]6, in which the two terminal {Ru(tpy)2}2+ and the central {M(tpy)2}2+ fragments are separated by diaza-18-crown-6 units. Electrospray mass spectrometry proved a very useful characterisational tool in all cases, showing a variety of charged species arising from both loss of anions and protonation of the basic amine sites in the aza-crown macrocycles: for [{(tpy)Ru(L2)}2Fe][PF6]6 for example intact complex cations were observed with charges of up to +9 (from loss of all six anions, and triple protonation). The mononuclear complexes [Ru(tpy)(HL1)][ClO4]2[PF6]·2MeCN·Et2O·H2O and [Ru(tpy)(L2)][PF6]2·0.7HPF6·0.3Et2O· MeCN·1.5H2O were crystallographically characterised. Electrochemical and electronic spectroscopic studies show that the {Ru(tpy)2}2+ and {M(tpy)2}2+ components of the trinuclear complexes are essentially electronically isolated.

Ruthenium(II) complexes of some new polynucleating ligands incorporating terpyridyl and macrocyclic aza-crown binding sites

A series of five new compounds has been prepared in which terpyridyl fragments are linked to hexadentate aza-crown macrocycles. Reaction of 1-aza-18-crown-6 (1,4,7,10,13-pentaoxa-16-azacyclooctadecane) and 1,10-diaza-18-crown-6 (1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) with 4′-bromo-2,2′:6′,2″-terpyridine afforded macrocycles L1–L3 in which the aza-crown macrocycles are linked directly to the C4′ position of the terpyridyl groups via the macrocyclic N atoms. Compounds L1 and L2 contain a single macrocycle (1-aza-18-crown-6 or 1,10-diaza-18-crown-6 respectively) attached to a terpyridyl group, whereas L3 contains two terpyridyl groups attached to either end of a central 1,10-diaza-18-crown-6-unit. Alternatively, the aza-crown macrocycles reacted with 4′-[(4-bromomethyl)phenyl]terpyridine to give L4 and L5 in which the aza-crown fragments are separated from the terpyridyl fragments by tolyl spacers: L4 contains one macrocycle attached to a terpyridyl core, whereas L5(like L3) contains two terpyridyl binding sites attached to either end of a central 1,10-diaza-18-crown-6 unit. Reaction of these with [Ru(terpy)Cl3] afforded the complexes [Ru(terpy)L1][PF6]2, [Ru(terpy)L2][PF6]2, [{Ru(terpy)}2(µ-L3)][PF6]4, [Ru(terpy)(HL4)][PF6]3 and [{Ru(terpy)}2(µ-H2L5)][PF6]6, the last two having the aliphatic amine groups of the macrocycles protonated. The crystal structure of [(terpy)Ru(L2)Na(BF4)2][PF6]·1.5Me2CO {grown by recrystallising [Ru(terpy)L2][PF6]2 from a medium containing traces of NaBF4} shows that the pendant N2O4-donor macrocyclic group contains a sodium cation co-ordinated by five of the six macrocyclic donor atoms, and two additional monodentate BF4– ligands in axial positions. Significantly, the N atom of the macrocycle which is attached to the terpyridyl fragment is sp2-hybridised with trigonal geometry, which permits the lone pair, in a pz orbital, to conjugate with the π system of the terpyridyl fragment. This macrocylic amine group is therefore a poor base and is not co-ordinated to the sodium cation. The crystal structure of [{Ru(terpy)}2(µ-H2L5)][PF6]6·2MeCN confirms that the central macrocycle is doubly protonated, with the extra protons inside the macrocyclic cavity consistent with an endocyclic disposition of lone pairs. The electrochemical and UV/VIS spectroscopic properties of the complexes were also examined: in the dinuclear complexes there is no electrochemical interaction between the remote metal centres across the saturated bridging group.