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Three quinoline-based zinc(ii)-Schiff base complexes were synthesized and characterized by X-ray crystallography. They exhibit remarkable aggregation-induced emission enhancement (AIEE) in acetonitrile/diethyl ether mixtures due to the conversion of weak luminescence in homogeneous solution into strong emission in the nano-aggregated phase after increasing the fractions of diethyl ether. Interestingly, the AIEE performance can be significantly promoted by joining the two quinoline units through an alkoxy chain. Moreover, they show reversible mechanochromic luminescence behavior between dark and bright states during the grinding-fuming cycles, due to the modulation of morphologies between amorphous and crystalline states. Introducing an electron donating group in the para-position of aniline significantly improves the mechanochromic luminescence effect with a more accessible and distinct emission colour contrast. The molecular packing in the crystalline phase and time-dependent density functional theory (TD-DFT) calculations demonstrate that multiple intermolecular C-Hπ and π-π interactions significantly strengthen the molecular rigidity and enhance the intramolecular charge-transfer (ICT) characteristics, leading to the effective emission enhancement in crystalline/nano-aggregated states. The novel AIEE and reversible mechanochromic luminescence properties point to the promising potential applications of these complexes in smart fluorescent materials.

We demonstrate a proof-of-concept design of a new platform for proton recognition and modulation. The new proton receptors are derived from a unique class of synthetic supercontainers that exhibit exceptional proton binding capacity (over 50 equiv.) and intriguing proton-dependent fluorescent switching behavior. Experimental and computational studies suggest that the proton-responsive event involves a two-step mechanism pertaining to proton binding by both amino and pyrenyl moieties of the supercontainer constructs. The high proton binding capacity of the supercontainers can be further modulated via small-molecule "regulators" that compete for the proton-binding sites, opening exiting new opportunities for proton manipulation in both chemistry and biology.

A new sulfonylcalix[4]arene-based dinuclear terbium molecular container (1) was conveniently synthesized and utilized as a fluorescence probe for the detection of a well-known biomarker 1-hydroxypyrene (1-OHP), which is used for the evaluation of polycyclic aromatic hydrocarbons (PAHs). The sulfonylcalix[4]arene ligand could not only serve as an efficient antenna ligand to promote the ligand-to-metal energy transfer but also provide a suitable cavity to accommodate 1-OHP. Promising fluorescence quenching effects were well established during the titration of the compound 1 with 1-OHP, and these effects were due to the enhancement in the host-guest intermolecular charge transfer and the decrease in the ligand-to-metal energy transfer after the formation of the stable host-guest complex. The fluorescence sensing mechanism was clearly understood through the titration experiments, and the data could be fit with the Benesi-Hildebrand and Stern-Volmer models. The TbIII-TBSC-based luminescent sensor exhibited quick response, high sensitivity, and specific selectivity to 1-OHP, even in the presence of other constituents in urine, thus providing a new sensing platform for the clinical diagnosis of human exposure to PAHs.

A series of Ag(i) and Cu(i) complexes [Ag3(L1)2][PF6]3 (8), [Ag3(L2)2][PF6]3 (9), [Cu(L1)][PF6] (10) and [Cu(L2)][PF6] (11) have been synthesized by reactions of the tridentate amine-bis(N-heterocyclic carbene) ligand precursors [H2L1][PF6]2 (6) and [H2L2][PF6]2 (7) with Ag2O and Cu2O, respectively. Complexes 10 and 11 can also be obtained by transmetalation of 8 and 9, respectively, with 3.0 equiv. of CuCl. A heterometallic Cu/Ag-NHC complex [Cu2Ag(L1)2(CH3CN)2][PF6]3 (12) is formed by the reaction of 8 with 2.0 equiv. of CuCl. All complexes have been characterized by NMR, electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffraction studies. The luminescence properties of 10-12 in solution and the solid state have been studied. At room temperature, 10-12 exhibit evident luminescence in solution and the solid state. The emission wavelengths are found to be identical at 483 nm in CH3CN, but they are 484, 480 and 592 nm in the solid state for 10-12, respectively. These results suggest that 12 dissociates into two molecules of 10 and Ag(i) ions in solution. Complex 12 is the first luminescent heterometallic Cu/Ag-NHC complex.

4,5-Bis(2-methyl-5-phenylthiophen-3-yl)-1,3-dithiol-2-one (L1o) was elaborately designed to afford dithienyl-dithiolene as a new photochromic ligand. We describe herein the preparation and characterization of unprecedented photochromic dithienyl-dithiolene complexes with cis-orientation of dithienylethene (DTE) stabilized by metal chelation instead of conventional cyclopentene. The treatment of L1o with sodium methoxide in methanol afforded a disodium salt of dithiolate dianion, which reacts with M(dppe)Cl 2 (dppe = 1,2-bis(diphenylphosphino)ethane, M = Ni, Pd) to give neutral compounds M(dppe)(dithiolate) as established by X-ray crystallography. The reaction of L1o with NiCl 2 in the presence of sodium methoxide allows the isolation of an anionic nickel(ii) bis(dithienyl-dithiolene) complex with photochemical inertness. In contrast, the corresponding reaction with ZnCl 2 afforded a dianionic zinc(ii) complex chelated by two dianionic dithienyl-dithiolenes, which displays stepwise photocyclization upon irradiation with UV light at 312 nm as demonstrated experimentally and theoretically. Only when dithienyl-dithiolene behaves as a dicationic ligand instead of neutral or monoanionic species, it is possible to achieve reversible photochromism in the corresponding metal complexes.

Cationic PtAu 2 heterotrinuclear complexes [PtAu 2 (dpmp) 2 (C[triple bond, length as m-dash]CR) 2 ] 2+ (dpmp = bis(diphenylphosphinomethyl)phenylphosphine, R = aryl) of aromatic acetylides were prepared. The PtAu 2 structures are supported through doubly bridging dpmp and stabilized by a significant Pt-Au interaction. They are highly phosphorescent in fluid CH 2 Cl 2 solution (Φ em = 23.5%-78.9%), the solid state (Φ em = 15.4%-70.2%), the PMMA film (Φ em = 39.9%-71.7%) and the doping film of 61% TCTA : 31% OXD-7 : 8% PtAu 2 complex (Φ em = 16.9%-67.9%). The phosphorescence arises mainly from 3 [π (C[triple bond, length as m-dash]CR) → π* (dpmp)] 3 LLCT and 3 [π (C[triple bond, length as m-dash]CR) → s/p (PtAu 2 )] 3 LMCT triplet excited states for carbazole-acetylide complexes, whereas other complexes display a 3 LLCT character mixed with noticeable PtAu 2 centered 3 [d → s/p] parentage. Utilizing a mixed host composed of hole-transporting TCTA and electron-transporting OXD-7 doped with 8% PtAu 2 species as a light-emitting layer and CuSCN as a hole-transporting layer through an orthogonal solution process, the devices exhibit highly efficient electrophosphorescence with the highest current efficiency (CE max ) of 51.7 cd A -1 and external quantum efficiency (EQE max ) of 14.5%. The efficiency roll-off is small in the practical brightness range of 500-5000 cd m -2 . The PtAu 2 complexes with carbazole-acetylides display a higher electroluminescence efficiency ascribed to their better hole-transporting character as well as more facile energy transfer from mixed host materials.

Heterodimetallic Ru-Fe complexes [(tppz)(PPh3)2RuL](ClO4) (L = C[triple bond, length as m-dash]CFc, [](ClO4); C[triple bond, length as m-dash]C-C6H4-C[triple bond, length as m-dash]CFc), [](ClO4); C[triple bond, length as m-dash]C-C6H4-C6H4-C[triple bond, length as m-dash]CFc, [](ClO4)) were synthesized by the reactions of [(tppz)(PPh3)2RuCl](ClO4) (tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine) with ferrocence-acetylide ligands and characterized by ESI-MS, and (1)H and (31)P NMR spectroscopies. The structure of [](PF6) was determined by X-ray crystallography. The electrochemical studies show that compounds [](ClO4)-[](ClO4) possess two widely separated anodic peaks, ascribable to one-electron oxidation of Fc and Ru(II), respectively. This assignment is further corroborated by the results of UV-vis-NIR, XPS, and theoretical calculation studies. Compound [](ClO4) exhibits significant RuFe metal-metal interactions across the Ru-C[triple bond, length as m-dash]C-Fc backbone. As revealed by electrochemical, spectroscopic and theoretical computational studies, one-electron oxidized species [](ClO4)2 is between the electronically delocalized and valence-trapped state and shows a typical Robin-Day class II mixed-valence behavior.

We have synthesized four Ir(iii) metal complexes () bearing dual fluorine-free cyclometalates that are derived from 2',6'-dimethoxy-4-t-butyl-2,3'-bipyridine (pypy)H or 2-(2,4-dimethoxypyrimidin-5-yl)-4-t-butylpyridine (pmpy)H and a third ancillary, e.g. 5-pyridin-2-yl-pyrazolate (Pz) or 5-pyridin-2-yl-pyrrolide (Pr), respectively. The Ir(iii) complexes and were examined by X-ray diffraction studies for providing the structural proofs. Photophysical properties were next measured in CH2Cl2 at RT, among which the pypy complexes and showed an identical structured emission with an E0-0 peak located at 458 nm, while the corresponding pmpy derivative displayed the most blue-shifted E0-0 peak at 444 nm. Organic light-emitting diodes (OLEDs) were fabricated using multiple layered architecture and the aforementioned phosphor at 8 wt% doping level. The associated OLED performances, cf. max. E.Q.E. = 9.0%, 14.3%, 5.8% and 9.4% and CIEx,y coordinates at (0.16, 0.22), (0.16, 0.24), (0.16, 0.17) and (0.16, 0.20) at 100 cd m(-2) for phosphors in sequence, confirmed their potential to act as blue dopants for phosphorescent OLEDs.

The planar platinum(II) complex [Pt(Me3SiC≡CbpyC≡CSiMe3)(C≡CC6H4Et-4)2] (1) with 5,5-bis(trimethylsilylethynyl)-2,2'-bipyridine was prepared and characterized. Solid-state 1 exhibits unusual, selective and reversible luminescence vapochromism to CH3CN and ClCH2CN vapors, which is useful for the detection of these hazardous vapors. A vapochromic cycle was monitored by dynamic variations in emission spectra and X-ray diffraction (XRD) patterns. Both X-ray crystallographic and density functional theory studies suggest that the vapochromic and vapoluminescent behavior of 1 are induced by the variation in the intermolecular Pt-Pt interactions.

A diiron dithiolate complex 1o with a dithienylethene (DTE) phosphine ligand has been elaborately designed and fully investigated by spectroscopic and DFT computational studies. Upon irradiation with UV light, the DTE moiety in complex 1o undergoes an excellent photocyclization reaction to attain ring-closed state 1c in high yield (>95%), accompanied by a colour change from orange to deep blue. On the other hand, upon irradiation with visible light (>460 nm), ring-closed form 1c in CH(3)CN solution reverts perfectly into ring-open form 1o. Both 1o and 1c were characterised by IR, (1)H, (31)P, (19)F NMR and electrochemical spectroscopy. The electrochemical behaviours of both the open and closed forms were investigated by cyclic voltammetry. Upon photocyclization reaction, a 290 mV (from -2.29 V to -2.00 V) positive shift is induced in the potential of electrochemical catalytic proton reduction, due to the electron-withdrawing effect of the ring-closed DTE moiety. Consequently, complex 1 can reversibly photoswitch the potential of proton reduction on the [FeFe] moiety.

A new self-assembled gadolinium(III)-aluminum(III) complex (Gd(3)Al) was synthesized and characterized. The efficacy of this Gd(3)Al complex as a potential bimodal magnetic resonance imaging (MRI)/optical imaging agent has been evaluated. Relaxivity studies showed that the Gd(3)Al complex has higher relaxation efficiency (7.18 mM(-1) s(-1)) compared with the clinically used complex gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA, 3.9 mM(-1) s(-1)) at 400 MHz and 25 °C. In vitro T(1)-MR images on a 0.5 T magnetic field exhibited a remarkable enhancement of signal contrast for Gd(3)Al compared to Gd-DTPA. Furthermore, the Gd(3)Al complex exhibits bright-green luminescence with the emission spectrum centred at 510 nm. Live-cell fluorescence imaging reveals that the Gd(3)Al complex is permeable to cells and localizes to the cytoplasm. In view of the relaxometric and luminescent properties, this Gd(3)Al complex could serve as a potential bimodal MRI/optical imaging agent.

A series of platinum(II) complexes with 1,3-bis(2-pyridylimino)isoindoline (BPI) derivatives were prepared by substitution of the coordinated Cl in the precursor complex Pt(BPI)Cl with a N-heterocyclic ligand such as pyridine, phthalazine or phenanthridine. These complexes display orange to red luminescence in fluid dichloromethane solutions and in the solid states at room temperature. The photophysical properties were tuned by introducing electron-withdrawing -NO(2) or electron-donating -NH(2) to the BPI ligand. The DFT computational studies suggest that the emission in the N-heterocyclic ligand substituted platinum(II) complexes originates mainly from the (3)[π→π*(BPI)] (3)IL triplet excited state, mixed with some (3)[dπ(Pt)→π*(BPI)] (3)MLCT character. Compared with the precursor Pt(BPI)Cl, both the low-energy absorption and the emission in the N-heterocyclic ligand substituted platinum(II) complexes exhibits a distinct blue-shift due to an obviously enhanced contribution from the (3)IL state and a reduced (3)MLCT character., (This journal is © The Royal Society of Chemistry 2011)

Three new dinuclear lanthanide(III) complexes {Eu(hfac)(3)(H(2)O)}(2)(μ-HPhMq)(2) (2) and {Ln(hfac)(3)(H(2)O)}(2)(μ-HMe(2)NC(6)H(4)Mq)(2) (Ln = Eu, 3; Nd, 4) with 8-hydroxylquinoline derivatives in μ-phenol mode were synthesized and characterized, where hfac(-) = hexafluoroacetylacetonate, HPhMq = 2-methyl-5-phenylquinolin-8-ol, and HMe(2)C(6)H(4)Mq = 5-(4-(dimethylamino)phenyl)-2-methylquinolin-8-ol. Compared with that (400 nm) for {Eu(hfac)(3)}(2)(μ-HMq)(2) (1, HMq = 2-methy-8-hydroxylquinoline), the excitation wavelength for sensitized lanthanide luminescence is extended to ca. 420 nm for 2, and 500 nm for 4 by introducing a phenyl or 4-(dimethylamino)phenyl to 8-hydroxylquinoline. These dinuclear lanthanide(III) complexes exhibit distinctly fluoride-induced lanthanide(III) emission enhancement in both intensity and lifetime due to replacing coordination water molecules or formation of strong O-H···F hydrogen bonds with coordinated H(2)O and μ-phenol, thus suppressing significantly the non-radiative O-H oscillators.

A new Cu(2+)-responsive MRI contrast agent (Gd-QDOTAMA) with a quinoline-based ligand was synthesized and characterized. Relaxivity studies on Gd-QDOTAMA showed that the relaxivity increased from 4.27 mM(-1) s(-1) to 7.29 mM(-1) s(-1) in response to equimolar amounts of copper(II) ion, corresponding to ca. 71% relaxivity enhancement. Distinct changes in relaxivity were undetected upon addition of physiologically relevant alkali metal cations (K(+) or Na(+)), alkaline earth metal cations (Mg(2+) or Ca(2+)), or d-block metal cations (Zn(2+), Cu(+), Fe(2+), Fe(3+)), indicating a high selectivity for Cu(2+) over other biologically relevant metal ions. Moreover, the influence of common biological anions at physiological levels on the Cu(2+)-responsive contrast agent was also studied. Luminescence studies on the Eu counterpart Eu-QDOTAMA suggest that the enhancement in relaxivity for Gd-QDOTAMA in response to Cu(2+) is most likely due to the increased number of inner-sphere water molecules around Gd(3+) upon Cu(2+) binding to the 8-amidequinoline moiety. In vitro T(1)-weighted phantom images of Gd-QDOTAMA confirmed that signal intensity was markedly increased by the addition of equimolar amounts of Cu(2+).

An iridium(III)-containing phosphorescent chemosensor Ir(ppy)(2)(L)(PF(6)) (1, ppy = 2-phenylpyridine) containing a 2,2'-bipyridyl ligand (L) functionalized with an alpha,beta-unsaturated ketone for selective detection of thiol was synthesized and characterized by spectroscopic and photophysical measurements. The structure of complex 1 was determined by X-ray crystallography. In order to get an insight into 1,4-addition reactions of thiol to complex 1, the adduct 2 from reaction of 1 with benzenethiol was successfully prepared and characterized. Complex 1 shows a lowest energy absorption at ca. 450 nm, primarily ascribable to an intraligand charge transfer (ILCT) transition from the HOMO (pi) resident on the fragment -C(O)C(6)H(4)N(C(2)H(5))(2) to the LUMO (pi*) localized on the 2,2'-bipyridyl moiety in the functionalized 2,2'-bipyridyl ligand as suggested from DFT computational studies. Complex 1 is weakly emissive at ca. 587 nm at ambient temperature, arising likely from the (3)ILCT excited state. Upon addition of thiol to a semi-aqueous solution of complex 1, the lowest energy absorption is obviously blue-shifted and the emission is remarkably enhanced due probably to a conversion from the primary ILCT state to the predominant [pi(ppy)-->pi*(L)] LLCT and the [5d(Ir)-->pi*(L)] MLCT state caused by the formation of the 1-thiol adduct. The sensing properties of 1 to thiol were also investigated by ESI-MS spectrometry and (1)H NMR spectroscopy.

Heterotrinuclear Zn(2)Ln (Ln = Nd 2, Eu 3, Tb 4, Er 5, Yb 6) clusters [(Znq(2))(2)](mu-CH(3)COO){Ln(hfac)(2)} (q = 8-hydroxylquinolinate, hfac = hexafluoroacetylacetonate) have been synthesized. The Zn(2)Ln framework is ligated by two q ligands featuring mu-phenoxo and two q ligands featuring mu(3)-phenoxo coordination modes, and one mu-CH(3)COO(-) anions. Since the short intramolecular separations of Zn...Ln (ca. 3.354-3.373 A) allow energy transfer from Znq(2)-based sensitizers to the Ln(III) centres through two energy transfer pathways, the lanthanide luminescence is indeed "lighted up" by excitation of the Znq(2)-based chromopores. Photophysical measurements revealed that these Zn(2)Ln complexes exhibit the so-called "dual emission" originating from both Znq(2)-based luminophores and lanthanide emitters. By virtue of the dual luminescence with complementary colours, the Znq(2)-based cyan emission and Eu(III)-centred red luminescence are combined to generate a white-light emission in the Zn(2)Eu (3) complex.

Heterotetranuclear Zn(2)Ln(2) (Ln = Nd , Eu , Sm , Er , Yb ) complexes {Zn(2)(Mq)(2)(tpyO)(2)}{(Ln(hfac)(3))(2)} (HMq = 2-methyl-8-hydroxylquinoline, tpyOH = [2,2':6'2'']terpyridin-4'-ol, hfac = hexafluoroacetylacetonate) display novel square structures ligated by bifunctional ligands tpyO (mono- and tridentate) and Mq (chelating and bridging mu-phenoxo). These compounds exhibit sensitized lanthanide emission upon photo-excitation of ZnMq/tpy antenna chromophores. By virtue of the dual luminescence with complementary colors, the ZnMq/tpyO-based cyan emission and Sm(III)-centered orange luminescence are combined to generate a white-light emission in Zn(2)Sm(2) (4) complex.

The reaction of 1,2-bis(5-(diphenylphosphino)-2-methylthien-3-yl) cyclopentene (PPh(2)-DTE-PPh(2)) with the triruthenium cluster precursor [Ru(3)O(OAc)(6)(py)(2)(CH(3)OH)](PF(6)) (1) gave monomeric or dimeric derivatives [Ru(3)O(OAc)(6)(py)(2){PPh(2)-DTE-PPh(2)}](PF(6)) ([2]PF(6)) and [{Ru(3)O(OAc)(6)(py)(2)}(2){mu-PPh(2)-DTE-PPh(2)}](PF(6))(2) ([3]PF(6)). Reduction of [2](+) and [3](2+) afforded one- or two-electron-reduced neutral products Ru(3)O(OAc)(6)(py)(2){PPh(2)-DTE-PPh(2)} (2) and {Ru(3)O(OAc)(6)(py)(2)}(2){mu-PPh(2)-DTE-PPh(2)} ()3, respectively. These triruthenium complexes show remarkable photochromism through photochemical ring-closing (UV light irradiation) and ring-opening (Vis light irradiation) processes as well as electrochromic properties through oxidation/reduction in the triruthenium cluster. Both the photochromic and electrochromic properties of 2 and 3 are highly reversible.

A series of oxo-centred triruthenium-acetate complexes with valence III,III,II were prepared by reactions of [Ru3(III,III,III)]+ precursor [Ru3O(OAc)6(py)2(CH3OH)]+ (1) with 3-chloro-6-(pyrazol-1-yl)pyridazine (cppd), 3-chloro-6-(3,5-dimethylpyrazol-1-yl)pyridazine (cmppd), 3,6-bis(pyrazol-1-yl)pyridazine (ppd), 3,6-bis(3,5-dimethylpyrazol-1-yl)pyridazine (mppd) or 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz). When neutral Ru3(III,III,II) precursor Ru3O(OAc)6(CO)(CH3OH)2 (2) was utilized, a stable low-valence Ru3(III,II,II) derivative complex was successfully isolated. As established through crystal structural analyses, they were derived from 1 or 2 by substitution of the axial methanol and one of six bridging acetates in the parent Ru3(mu3-O)(mu-OAc)6 cluster core as well as one axial pyridine in some cases. As revealed by electrochemical and spectroscopic studies, substituting one of the six bridging acetates in the parent Ru3(mu3-O)(mu-OAc)6 cluster core significantly modifies the electronic and redox characteristics. Compared with those for the parent compound [Ru3O(OAc)6(py)3]+, triruthenium-based redox potentials of these derivatives show remarkable positive shifts.

Reactions of 5-[2-(trimethylsilyl)-1-ethynyl]-2,2'-bipyridine (Me3SiC-Cbpy) with Pt(bpy)C12 (bpy = 2,2'-bipyridine) and Pt(bpyC[triple bond]C-C[triple bond]Cbpy)Cl2 (bpyC[triple bond]C-C[triple bond]Cbpy=bis(2,2'-bipyridin-5-yl)butadiyne) induced isolation of Pt(bpy)(C[triple bond]Cbpy)2 (1) and Pt(bpyC[triple bond]C-C[triple bond]Cbpy)(C[triple bond]Cbpy)2 (5), respectively. Incorporating Ln(hfac)3(H2O)2 (hfac = hexafluoroacetylacetone) with 1 or 5 gave the corresponding PtLn2 (Ln = Nd (2), Eu (3), Yb (4)) or PtLn3 arrays (Ln=Nd (6), Eu (7), Gd (8), Yb (9)). With excitation at 360 < or = lamda(ex)0 < or =480 nm, which is the MLCT absorption region of the Pt(2,2'-bipyridyl)(acetylide)2 chromophore, sensitized lanthanide luminescence is successfully attained by efficient Pt-->Ln energy transfer from the Pt(II) antenna chromophores. In contrast with quite efficient Pt-->Ln energy transfer in the Pt-C[triple bond]Cbpy-Ln(Pt...Ln = 8.6 A) array, energy transfer transmitted across the Pt-bpyC[triple bond]C-C[triple bond]Cbpy-Ln(Pt...Ln = 13.3 A) array is less efficient owing to the much longer Pt...Ln separation in the latter.

A series of mono-, di- and trimeric oxo-centred triruthenium cluster compounds with ortho-metallated polypyridyl ligands were prepared by reaction of oxo-centred triruthenium precursor compound [Ru3O(OAc)6(py)2(CH3OH)]+ (1) with bis(2,2'-bipyridin-5-yl)butadiyne (bpyC[triple bond, length as m-dash]C-C[triple bond, length as m-dash]Cbpy), bis(2,2'-bipridin-5-yl)ethyne (bpyC[triple bond, length as m-dash]Cbpy), 2,2'-bipyrazine (bpz), pyrazino[2,3-f]quinoxaline (pyq), or 4,7-phenanthroline (4,7-phen). As revealed by redox wave splitting, electronic interactions are operating between two Ru3O redox centres in most of the triruthenium cluster dimers and trimers. The cluster-cluster interactions are highly sensitive to the variations in bonding modes of the polypyridyl ligands. Ortho-metallation of the bridging ligand induces an enhanced electronic interaction between two triruthenium centres.

Polypyridyl-functionalized alkynes are a class of bifunctional ligands and very useful for the design of heteropolynuclear or multicomponent arrays as optoelectronic materials at the molecular level. This article focuses on reviewing the recent progress in design of luminescent heteropolynuclear or multicomponent complexes composed of photoactive discrete subunits using 2,2'-bipyridyl, 1,10-phenanthroline or 2,2':6',2''-terpyridyl functionalized alkynyl ligands with both acetylide and polypyridyl groups. The preparation, molecular fabrication, structural features, and spectroscopic and luminescent properties are summarized to elucidate the correlation of structure and photophysical properties as well as triplet energy transfer between two or more photoactive organometallic subunits.

A series of platinum(II) terpyridyl complexes with phenolic ethynyl ligands have been synthesized and characterized. Their photophysical and sensing properties towards anions such as fluoride, acetate and dihydrogenphosphate have been investigated. These complexes show a colorimetric response and fluorescence quenching in the presence of anions including fluoride, acetate and dihydrogenphosphate, and selective sensing towards fluoride in some cases. The sensing mechanism has been investigated by spectrophotometric and 1H NMR titration.