Weak Phosphorescence Research Articles

Ultrabroad-band, white light emission from carbon dot-based materials with hybrid fluorescence/phosphorescence for single component white light-emitting diodes

Benefiting from the large Stokes shift between fluorescence and phosphorescence, fluorescence/phosphorescence dual-emitting carbon dots (CDs) have gradually entered at the stage of single-phase white light-emitting diodes (WLEDs) as ‘green material’. However, most of the developed dual-emitting CDs have weak phosphorescence, short emission wavelength and narrow emission band, resulting in relatively bluish white light emission and low color rendering index (CRI). Herein, an ultrabroad-band fluorescence/phosphorescence dual-emitting CD-based material (UB-CD@BA) is prepared by thermal treatment of boric acid (BA) and CDs with large conjugated structure. The stable covalent bonding between CDs and BA, as well as three-dimensional spatial restriction effect of self-polymerization BA molecules around CDs during long-term heating efficiently rigidified the single/triplet excited states of CDs from non-radiative deactivation, thus producing strong dual emissive materials with the high phosphorescence quantum yield of 21%. Remarkable, the prepared UB-CD@BA powders exhibit bright pure white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.32, 0.33) and the highest reported full width at half maximum of 250 nm. Based on the unique characteristics of UB-CD@BA, it was used as a color conversion layer to prepare a WLED with CIE coordinates of (0.35, 0.33) and the CRI value of 87.

Persulfurated Benzene-Cored Asterisks with π-Extended ThioNaphthyl Arms: Synthesis, Structural, Photophysical and Covalent Dynamic Properties.

The synthesis of regioisomeric asterisks (5) and (6) incorporating a benzene core with six 1‐naphthylthio or six 2‐naphthylthio arms are reported in search for new materials with optoelectronic properties. The consequences on the extension of a π system surrounding a persulfurated benzene core provide a new avenue to study the structural, photophysical, and chemical properties of such family of all‐organic phosphors. It also diverts the persulfuration mechanism after two radical cyclizations for making a [5]dithiohelicene by‐product (7) and favors dynamic sulfur component exchange reactions surrounding the core. These exchanges convert asterisks (5) and (6), non‐phosphorescent at 20 °C to the highly phosphorescent (4) (ϕ ∼100 %, solid state at 20 °C). For asterisks (5) and (6), the absence of the typical phosphorescence of the per(phenylthio)benzene core in the solid state at 20 °C and the presence of a weak naphthalene‐based phosphorescence at 77 K is attributed to an energy transfer from the triplet state of the persulfurated benzene core to the outer naphthalene moieties, resulting in an antenna system.

BODIPY-Based Polymers of Intrinsic Microporosity for the Photocatalytic Detoxification of a Chemical Threat.

Effective heterogeneous photocatalysts capable of detoxifying chemical threats in practical settings must exhibit outstanding device integrity. We report a copolymerization that yields robust, porous, processible, chromophoric BODIPY (BDP; boron-dipyrromethene)-containing polymers of intrinsic microporosity (BDP-PIMs). Installation of a pentafluorophenyl at the meso position of a BDP produced reactive monomer that when combined with 5,5,6,6-tetrahydroxy-3,3,3,3-tetramethyl-1,1-spirobisindane (TTSBI) and tetrafluoroterephthalonitrile (TFTPN) yields PIM-1. Postsynthetic modification of these polymers yields Br-BDP-PIM-1a and -1b─polymers containing bromine at the 2,6-positions. Remarkably, the brominated polymers display porosity and processability features similar to those of H-BDP-PIMs. Gas adsorption reveals molecular-scale porosity and Brunette-Emmet-Teller surface areas as high as 680 m2 g-1. Electronic absorption spectra reveal charge-transfer (CT) bands centered at 660 nm, while bands arising from local excitations, LE, of BDP and TFTPN units are at 530 and 430 nm, respectively. Fluorescence spectra of the polymers reveal a Förster resonance energy-transfer (FRET) pathway to BDP units when TFTPN units are excited at 430 nm; weak phosphorescence at room temperature indicates a singlet-to-triplet intersystem crossing. The low-lying triplet state is well positioned energetically to sensitize the conversion of ground-state (triplet) molecular oxygen to electronically excited singlet oxygen. Photosensitization capabilities of these polymers toward singlet-oxygen-driven detoxification of a sulfur-mustard simulant 2-chloroethyl ethyl sulfide (CEES) have been examined. While excitation of CT and LEBDP bands yields weak catalytic activity (t1/2 > 15 min), excitation to higher energy states of TFTPN induces significant increases in photoactivity (t1/2 ≅ 5 min). The increase is attributable to (i) enhanced light collection, (ii) FRET between TFTPN and BDP, (iii) the presence of heavy atoms (bromine) having large spin-orbit coupling energies that can facilitate intersystem crossing from donor-acceptor CT-, FRET-, or LE-generated BDP singlet states to BDP-related triplet states, and (iv) polymer triplet excited-state sensitization of the formation of CEES-reactive, singlet oxygen.

A host-guest organic afterglow system with significant guest induced enhancement of phosphorescence

In this article, an effective host-guest system with intense afterglow and stimuli-responsive properties is described. Br-BID-Py (host) crystals emit weak phosphorescence and NMe2-BID-Py (guest) crystals are not phosphorescent. However, when NMe2-BID-Py is doped into the Br-BID-Py crystals, the afterglow of the host is enhanced. The afterglow exhibits a unique thermally activated property, which is due to the effective intersystem crossing from the guest to the host via energy transfer. Br-BID-Py (host) and NMe2-BID-Py (guest) show small structural differences, which facilitate energy transfer with each other in the crystal state. The energy transfer process is evidenced by excitation photoluminescence spectra and UV–vis absorption spectra. To date, the host-guest afterglow organic system where the guest enhances the intrinsic afterglow of the host is rarely reported. Moreover, both Br-BID-Py and NMe2-BID-Py display stimuli-responsive properties because of protonation of pyridine, which is inherited by the hybrid host-guest crystals. The host-guest crystals demonstrate rare proton-induced afterglow shift observed by direct visualization by eye. Finally, the application of the host-guest afterglow material and its stimulus-responsive property in information encryption is displayed. To our best knowledge, this example is a rare stimulus-responsive organic afterglow material fabricated via the strategy of a host-guest doping system.

Excitation-dependent organic phosphors exhibiting different luminescence colors for information anti-counterfeiting

The development of organic phosphors with excitation-dependent luminescence color is tremendously challenging for organic room temperature phosphorescent (ORTP) systems. Herein, we designed and synthesized a series of novel ORTP materials based on pyranone. Under the excitation of 254 nm, the materials exhibited the rare phenomenon of emitting almost pure phosphorescence, whereas strong cyan photoluminescence and weak green phosphorescence were observed upon exposure to 360 nm excitation light. Experiment analysis and theoretical calculations demonstrate that the regulation of luminescent color is attributed to the different transition process of excitons from singlet excited states (S1 and S2) to triplet excited states (T1) under various excitation wavelengths. The materials still can maintain the crystalline state under various extreme conditions (ground, recrystallization, high pressure), thereby maintaining the ORTP properties. In addition, the ORTP properties of the materials are very stable to water/heat/light/air. Taking advantage of the multiple luminescence colors, excellent crystallinity and stability, these phosphors can be developed as an advanced anti-counterfeiting ink for printing and hand-painting on a wide range of media, showing an extremely ideal application prospect.

Photophysics and solar cell application of a benzodithiophene conjugated polymer containing cyclometalated platinum units

Cyclometalated platinum(II) chromophores were combined with benzodithiophene (BDT) units to form a conjugated molecule and polymer in order to ascertain their photophysical and electrochemical properties, as well as their potential for use in bulk heterojunction organic solar cells. Weak fluorescence and room temperature phosphorescence were observed for both the small molecule model complex and polymer, leading to the assumption that the presence of platinum metal centers serves to enhance intersystem crossing (ISC). Nanosecond and picosecond transient absorption spectroscopy were employed to study the excited state dynamics which revealed ISC rates of the polymers (3 × 1012 s−1) is faster than that of the model (2.5 × 1011 s−1). These fast ISC rates ensure a high population of triplet excited states, which was confirmed by singlet oxygen sensitization measurements. A laser power dependence of the triplet yield was observed to be more pronounced for the polymer, likely due to triplet-triplet annihilation within single polymer chains. Unfortunately, energy level estimations from electrochemistry and emission spectra placed the triplet state at or below the energy of the charge transfer state to PCB71M acceptor. Organic solar cells were constructed using the model or polymer as donor in conjunction with PC71BM as acceptor. The polymer donor provided the higher photocurrent efficiency at just over 1% in a non-optimized device.

A Halomanganates(II) with P,P'-Diprotonated Bis(2-Diphenylphosphinophenyl)ether: Wavelength-Excitation Dependence of the Quantum Yield and Role of the Non-Covalent Interactions.

A [H2DPEphos][MnX4] [X = Br, Cl] tetrahalomanganates(II) with P,P’-diprotonated bis[2-(diphenylphosphino)phenyl]ether cation has been designed and investigated in photophysics and EPR terms. The complexes exhibit a green luminescence resulted from the Mn(II) d–d transitions (4T1→6A1) with the wavelength-excitation dependence of the quantum yield. The solid [H2DPEphos][MnBr4] complex exhibits a bright green phosphorescence (λmax = 515 nm) with the high luminescence quantum yield depending on the excitation energy whereas the solid [H2DPEphos][MnCl4] complex exhibits a very weak phosphorescence (λmax = 523 nm). The unexpected shorter luminescence lifetime for the [H2DPEphos][MnCl4] than for the [H2DPEphos][MnBr4] at 300 K can be a result of the higher non-radiative relaxation contribution. On the one hand, the non-covalent PH…X(Mn) interactions quench the manganese(II) luminescence. On the other hand, the PH…X(Mn) interactions are a pathway of the excitation transfer from [H2DPEphos]2+ to [MnX4]2−.

Coordination-Driven Self-Assembly of Cyclometalated Iridium Squares Using Linear Aromatic Diisocyanides.

Here, we demonstrate facile [4 + 4] coordination-driven self-assembly of cyclometalated iridium(III) using linear aryldiisocyanide bridging ligands (BLs). A family of nine new [Ir(C^N)2(μ-BL)]44+ coordination cages is described, where C^N is the cyclometalating ligand-2-phenylpyridine (ppy), 2-phenylbenzothiazole (bt), or 1-phenylisoquinoline (piq)-and BL is the diisocyanide BL, with varying spacer lengths between the isocyanide binding sites. These supramolecular coordination compounds are prepared via a one-pot synthesis, with isolated yields of 40-83%. 1H NMR spectroscopy confirms the selective isolation of a single product, which is affirmed to be the M4L4 square by high-resolution mass spectrometry. Detailed photophysical studies were carried out to reveal the nature of the luminescent triplet states in these complexes. In most cases, phosphorescence arises from the [Ir(C^N)2]+ nodes, with the emission color determined by the cyclometalating ligand. However, in two cases, the lowest-energy triplet state resides on the aromatic core of the BL, and weak phosphorescence from that state is observed. This work shows that aromatic diisocyanide ligands enable coordination-driven assembly of inert iridium(III) nodes under mild conditions, producing supramolecular coordination complexes with desirable photophysical properties.

Phenyl-pyta-tricarbonylrhenium(I) complexes: combining a simplified structure and steric hindrance to modulate the photoluminescence properties.

Strongly luminescent tricarbonylrhenium(I) complexes are promising candidates in the field of optical materials. In this study, three new complexes bearing a 3-(2-pyridyl)-1,2,4-triazole (pyta) bidentate ligand with an appended phenyl group were obtained in very good yields owing to an optimized synthetic procedure. The first member of this series, i.e. complex 1, was compared with the previously studied complex RePBO to understand the influence of the fluorescent benzoxazole unit grafted on the phenyl ring. Then, to gauge the effect of steric hindrance on the luminescence properties, the phenyl group of complex 1 was substituted in the para position by a bulky tert-butyl group or an adamantyl moiety, affording complexes 2 and 3, respectively. The results of theoretical calculations indicated that these complexes were quite similar from an electronic point of view, as evidenced by the electrochemical study. In dichloromethane solution, under excitation in the UV range, all the complexes emitted weak phosphorescence in the red region. In the solid state, they could be excited in the blue region of the visible spectrum and they emitted strong yellow light. The photoluminescence quantum yield was markedly increased with raising the size of the substituent, passing from 0.42 for 1 to 0.59 for 3. The latter complex also exhibited clear waveguiding properties, unprecedented for rhenium complexes. From this point of view, these easy-synthesized and spectroscopically attractive complexes constitute a new generation of emitters for use in imaging applications and functional materials. However, the comparison with RePBO showed that the presence of the benzoxazole group leads to unsurpassed mechanoresponsive luminescence (MRL) properties, due to the involvement of a unique photophysical mechanism that takes place only in this type of complex.

Multidimensional Structure Conformation of Persulfurated Benzene for Highly Efficient Phosphorescence.

It is a challenge to acquire, realize, and comprehend highly emissive phosphorescent molecules. Herein, we report that, using persulfurated benzene compounds as models, phosphorescence can be strongly enhanced through the modification of molecular conformation and crystal growth conditions. By varying the peripheral groups in these compounds, we were able to control their molecular conformation and crystal growth mode, leading to one- (1D), two- (2D), and three-dimensional (3D) crystal morphologies. Two kinds of typical molecular conformations were separately obtained in these crystals through substituent group control or the solvent effect. Importantly, a symmetrical 3,3-conformer exhibits that a planar central benzene ring prefers a 3D-type crystal growth mode, demonstrating high phosphorescence efficiency. Such outcome is attributed to the strong crystal protection effect of the 3D crystal and the bright global minimum (GM) boat-like T1 state of the symmetrical 3,3-conformer. The conformation studies further reveal small deformation of the inner benzene ring in both singlet and triplet states. The GM boat-like T1 state is indicated by theoretical calculations, which is far away from the conical intersection (CI) point between the S0 and T1 potential energy surfaces. Meanwhile, the small energy gap between S1 and T1 states and the considerable spin-orbit coupling matrix elements allow an efficient population of the T1 state. Combined with the crystal protection and conformation effect, the 3,3-conformer crystal shows high phosphorescence efficiency. The unsymmetrical 2,4-conformer conformation with the twisted central benzene ring leads to 1D or 2D crystal growth mode, which has a weak crystal protection effect. In addition, the unsymmetrical conformation has a dark GM T1 state that is very close to the T1-S0 CI point, implying an efficient nonradiative T1-S0 quenching. Thus, weak phosphorescence was observed from the unsymmetrical conformation. This study provides an insight for the development of highly emissive phosphorescent materials.

Double-Stranded DNA Matrix for Photosensitization Switching

Photosensitization, originated from the activation of triplet states, is the basis of many photodynamic applications, but often competes with a series of nonradiative processes. Herein, we communic...

Structure and Luminescence Properties of Lutetium(Iii) Complexes with 5,10,15,20-Tetraphenylporphine and its Derivatives

The spectral and luminescent properties of new complexes of lutetium(III)–chloride with 5,10,15,20-tetraphenylporphine and its mono-nitrophenyl derivative with a para-nitro group on one of the meso-phenyl rings were studied. The complexes showed weak fluorescence (φfl = 5·10–4) and moderate phosphorescence (φphosph = 3·10–2) at 77 K and phosphorescence at room temperature. The type of extra ligand (monodentate chloride and bidentate acetylacetonate) and the presence of an electron-withdrawing NO2 group on the meso-phenyl ring did not have an appreciable effect on the photophysics of the Lu(III)-porphyrins. The phosphorescence spectra of the complexes were shifted to the long-wavelength region. The phosphorescence lifetimes were longer (2800–3100 μs) than those of the known oxygen sensors Pt(II)- or Pd(II)-porphyrins. The oxygen determination limit in solution was estimated from quenching of the Lu(III)-porphyrin phosphorescence.

Delayed radioluminescence of some heterostructured organic scintillators

The processes leading to the appearance of phosphorescence and delayed fluorescence in organic molecular materials compete. This paper compares the ratio of the intensities of delayed fluorescence and phosphorescence with the pulse shape discrimination (PSD) capability of organic scintillators. The paper considers hot-pressed polycrystals and composite samples containing single-crystal organic grains as the heterostructured organic scintillators.The single crystals and heterostructured scintillators contained trans-stilbene, p-terphenyl, anthracene, and phenanthrene. Samples based on trans-stilbene and p-terphenyl at 77 K showed an intense delayed fluorescence, which appeared against the background of weak phosphorescence. It indicates the active formation of delayed fluorescence in these materials. We did not observe a similar effect for samples based on anthracene and phenanthrene. At the same time, it was the samples containing trans-stilbene and p-terphenyl grains that showed the best PSD capability at room temperature. Single-crystal and heterostructured materials containing the same scintillation substance demonstrate a close PSD capability. A comparative analysis of the intensities of delayed fluorescence and phosphorescence at low temperatures can be a method of searching for new materials that are promising for PSD problems.

Iridium Corroles Exhibit Weak Near-Infrared Phosphorescence but Efficiently Sensitize Singlet Oxygen Formation

Six-coordinate iridium(III) triarylcorrole derivatives, Ir[TpXPC)]L2, where TpXPC = tris(para-X-phenyl)corrole (X = CF3, H, Me, and OCH3) and L = pyridine (py), trimethylamine (tma), isoquinoline (isoq), 4-dimethylaminopyridine (dmap), and 4-picolinic acid (4pa), have been examined, with a view to identifying axial ligands most conducive to near-infrared phosphorescence. Disappointingly, the phosphorescence quantum yield invariably turned out to be very low, about 0.02 – 0.04% at ambient temperature, with about a two-fold increase at 77 K. Phosphorescence decay times were found to be around ~5 µs at 295 K and ~10 µs at 77 K. Fortunately, two of the Ir[TpCF3PC)]L2 derivatives, which were tested for their ability to sensitize singlet oxygen formation, were found to do so efficiently with quantum yields Φ(1O2) = 0.71 and 0.38 for L = py and 4pa, respectively. Iridium corroles thus may hold promise as photosensitizers in photodynamic therapy (PDT). The possibility of varying the axial ligand and of attaching biotargeting groups at the axial positions makes iridium corroles particularly exciting as PDT drug candidates.

Iridium(Ⅲ) complex-based phosphorescent probe for rapid, specific, and sensitive detection of phosgene

Due to the high toxicity and commercial availability of phosgene, there is an urgent need for rapid and reliable detection of phosgene in order to deal with a potentially severe threat to public security caused by terrorist and accidental industrial release. In this work, an iridium(Ⅲ) complex, Ir-OXIME, has been developed as a fast, highly sensitive and selective sensor for phosgene. Ir-OXIME displayed very weak phosphorescence due to quenching caused by the CN–OH moiety. After reacting with phosgene, the oxime is converted to a nitrile to form the brightly phosphorescent product, Ir–CN. Ir-OXIME exhibited a rapid response (<5 s), a low detection limit (2.4 nM), and a high selectivity towards phosgene in solution. The Stokes shift of Ir-OXIME reaches 294 nm, which prevented signal crosstalk and consequently improved sensing accuracy. Finally, test papers with Ir-OXIME immobilized on filter paper were designed and prepared as a practical detection tool of phosgene gas.

Meso‐(2‐Pyridyl)‐boron(III)‐subporphyrin: Perimeter Iridium(III) Coordination

AbstractPeripherally metalated porphyrinoids are promising functional π‐systems displaying characteristic optical, electronic, and catalytic properties. In this work, 5‐(2‐pyridyl)‐ and 5,10,15‐tri(2‐pyridyl)‐BIII‐subporphyrins were prepared and used to produce cyclometalated subporphyrins by reactions with [Cp*IrCl2]2, which proceeded through an efficient C−H activation to give the corresponding mono‐ and tri‐IrIII complexes, respectively. While the mono‐IrIII complex was obtained as a diastereomeric mixture, a C3‐symmetric tri‐IrIII complex with the three Cp*‐units all at the concave side was predominantly obtained in a high yield of 90 %, which displays weak NIR phosphorescence even at room temperature in degassed CH2Cl2, differently from the mono‐IrIII complexes.

Meso-(2-Pyridyl)-boron(III)-subporphyrin: Perimeter Iridium(III) Coordination.

Peripherally metalated porphyrinoids are promising functional π-systems displaying characteristic optical, electronic, and catalytic properties. In this work, 5-(2-pyridyl)- and 5,10,15-tri(2-pyridyl)-BIII -subporphyrins were prepared and used to produce cyclometalated subporphyrins by reactions with [Cp*IrCl2 ]2 , which proceeded through an efficient C-H activation to give the corresponding mono- and tri-IrIII complexes, respectively. While the mono-IrIII complex was obtained as a diastereomeric mixture, a C3 -symmetric tri-IrIII complex with the three Cp*-units all at the concave side was predominantly obtained in a high yield of 90 %, which displays weak NIR phosphorescence even at room temperature in degassed CH2 Cl2 , differently from the mono-IrIII complexes.

Cocrystals with tunable luminescence colour self-assembled by a predictable method

Organic light-emitting materials play an essential role in the field of luminescent materials because they are easily prepared and they have controllable luminescent properties. Here it is shown that intermolecular interactions and luminescent properties of cocrystals can be predicted using the molecular surface electrostatic potential of selected π-hole/σ-hole...π bonding donor haloperfluorobenzenes and acceptor acenaphthene (AC). Single-crystal X-ray diffraction data reveal that actual bonding patterns in five cocrystals assembled from haloperfluorobenzenes and AC are in accordance with predictable patterns of intermolecular interactions; that is π-hole...π bond is the major interaction in AC–octafluoronaphthalene, AC–1,4-dibromotetrafluorobenzene and AC–1,3,5-tribromo-2,4,6-trifluorobenzene cocrystals, whereas σ-hole...π bond is the major interaction in AC–1,4-diiodotetrafluorobenzene and AC–1,3,5-trifluoro-2,4,6-triiodobenzene cocrystals. The luminescent properties of the cocrystals are affected by the bonding patterns between AC and haloperfluorobenzenes; the π-hole...π bond leads to weak phosphorescence, whereas the σ-hole...π bond results in weak delayed fluorescence and relatively strong phosphorescence.

Thermally Activated Delayed Fluorescence (TADF) Path toward Efficient Electroluminescence in Purely Organic Materials: Molecular Level Insight.

Since the seminal work of Tang and Vanslyke in 1987 on small-molecule emitters and that of Friend and co-workers in 1990 on conjugated-polymer emitters, organic light-emitting diodes (OLEDs) have attracted much attention from academia as well as industry, as the OLED market is estimated to reach the $30 billion mark by the end of 2018. In these first-generation organic emitters, on the basis of simple spin statistics, electrical excitation resulted in the formation of ∼25% singlet excitons and ∼75% triplet excitons. Radiative decay of the singlet excitons to the singlet ground state leads to a prompt fluorescence emission, while the triplet excitons only lead to weak phosphorescence due to the very small spin-orbit couplings present in purely organic molecules. The consequence is a ca. 75% energy loss, which triggered wide-ranging efforts to try and harvest as many of the triplet excitons as possible. In 1998, Thompson, Forrest, and their co-workers reported second-generation OLED emitters based on coordination complexes with heavy transition metals (e.g., iridium or platinum). Here, the triplet excitons stimulate efficient and fast phosphorescence due to the strong spin-orbit couplings enabled by the heavy-metal atoms. Internal quantum efficiencies (IQE) up to 100% have been reported, which means that for every electron injected into the device, a photon is emitted. While these second-generation emitters are those mainly exploited in current OLED applications, there is strong impetus from both cost and environmental standpoints to find new ways of exploiting purely organic emitters, which in addition can offer greater flexibility to fine-tune the electronic and optical properties by exploiting the synthetic organic chemistry toolbox. In 2012, Adachi and co-workers introduced a promising strategy, based on thermally activated delayed fluorescence (TADF), to harvest the triplet excitons in purely organic molecular materials. These materials now represent the third generation of OLED emitters. Impressive photophysical properties and device performances have been reported, with internal quantum efficiencies also reaching nearly 100%. Our objectives in this Account are threefold: (i) to lay out a comprehensive description, at the molecular level, of the fundamental photophysical processes behind TADF emitters; (ii) to discuss some of the challenges facing the design of TADF emitters, such as the need to balance the efficiency of thermal activation of triplet excitons into the singlet manifold with the efficiency of radiative transition to the ground state; and (iii) to highlight briefly some of the recent molecular-design strategies that pave the way to new classes of TADF materials.

Structural and luminescent properties of homo- and heterometallic complexes of La, Li and Na with 2-(2-benzoxyazol-2-yl)phenolate ligands

A series of homo and heterometallic La, Li and Na complexes with 2-(2-benzoxyazol-2-yl)phenolate (L) ligands were synthesized using La[N(SiMe3)2]3 and M[N(SiMe3)2] (M = Li, Na) or La(Cp)3 as starting materials for La2(L)6 (1), La2(L)6(bipy) (2), La(L)2Cp(DME) (3), La2Li(L)7 (4), Li(L) (5), Na(L) (6). Photoluminescent (PL) properties of these compounds, staring phenol H(L) as well as previously obtained complex LaNa(L)4(DME)2 (7) were studied at 300 and 77 K. Molecular structure of 2, 3 and 4 were determined by X-ray analysis. All the compounds in THF solution at 300 K upon UV excitation (370 nm) revealed a bright fluorescence in the range 430–460 nm and moderate phosphorescence as a shoulder at about 500 nm. The total quantum yield (QY) is 1–35%. At 77 K all lanthanum compounds (except 3) in THF solution exhibit weak or moderate fluorescence but intense phosphorescence (τ 3.5 – 95.8 ms). The PL spectra of solid samples at 300 K strongly differ from those of solutions, apparently due to the effects of crystal packing, the shape and size of the crystals. The emission of H(L) is most intensive but the PL of 1 has lowest efficiency. It is assumed that phosphorescence occurs from excimers and exciplexes, the formation of which in the compounds studied has been confirmed by X-ray diffraction analysis.