Electron-deficient Acceptor Research Articles

One-Pot Synthesis of Vinylogous Cyano Aminoaryls (VinCAs) as Benzenic Fluorophores: Tailoring Diverse Emission Colors for White Light Emitting Materials and Cell Imaging.

Donor-acceptor-based organic small molecules with an electronic push-pull effect can demonstrate intramolecular charge transfer to show interesting photoluminescence properties. This is an essential criterion for designing fluorogenic probes for cell imaging studies and the development of organic light-emitting diodes. Now, to design such optical materials sometimes it is necessary to tune the band gap by controlling the energies of the highest occupied molecular orbital and lowest unoccupied molecular orbital. Typically, the band gaps could be modulated by installing unsaturated handles between electron-rich donors and electron-deficient acceptors. However, these methods are often synthetically and economically challenging due to the involvement of expensive catalysts and difficult reaction setups. In our present study, we show a straightforward, cost-effective method for obtaining a series of donor-acceptor-type Vinylogous Cyano Aminoaryls (VinCAs) with diverse emission colors. Further studies reveal that these VinCAs can serve as effective cell imaging agents, showcasing potential use in chemical biology. Additionally, these molecules could be further used to generate white light emission (WLE), showing their potential utility in advanced lighting technologies.

Lewis Acid-Driven Inverse Hydride Shuttle Catalysis.

Inverse hydride shuttle catalysis provides a multicomponent platform for the highly efficient synthesis of alkaloid frameworks with exquisite diastereoselectivity. However, a number of limitations hinder this method, primarily the strict requirement for highly electron-deficient acceptors. Herein, we present a general Lewis acid-driven approach to address this constraint, and have developed two broad strategies enabling the modular synthesis of complex azabicycles that were entirely unattainable using the previous method. The enhanced synthetic flexibility facilitates a streamlined asymmetric cyclization, leading to a concise total synthesis of the alkaloid (-)-tashiromine.

Acidic Hydrogen-Tethered Electron-Deficient Acceptors for Phosphine-Catalyzed Annulations

AbstractNucleophilic phosphine-catalyzed annulations are recognized as practical and powerful tools for synthesizing various cyclic compounds. Phosphine acceptors play a key role in nucleophilic phosphine catalysis. The design and synthesis of new phosphine acceptors that are able to introduce new zwitterionic intermediates with new reactivities into phosphine-catalyzed annulations is highly desirable. We recently applied proton-shift principles in the design of new phosphine acceptors, and we synthesized several new acceptors. With the use of these acceptors, we have developed several novel phosphine-catalyzed annulation reactions. In this account, we present a brief introduction to the design and application of a series of acidic-hydrogen-tethered electron-deficient acceptors for phosphine-catalyzed annulation reactions, categorized according to the type of atom (N–H, O–H, C–H) to which the acidic hydrogen is bound.1 Introduction2 Phosphine Acceptors Tethered with an Acidic N–H Group3 Phosphine Acceptors Tethered with an Acidic O–H Group4 Phosphine Acceptors Tethered with an Acidic C–H Group5 Conclusions

Hydrophilic Cocrystals with Water Switched Luminescence.

Utilizing water molecules to regulate the luminescence properties of solid materials is highly challenging. Herein, we develop a strategy to produce water-triggered luminescence-switching cocrystals by coassembling hydrophilic donors with electron-deficient acceptors, where 1,2,4,5-Tetracyanobenzene (TCNB) was used as the electron acceptor and pyridyl benzimidazole derivatives were used as the electron donors enabling multiple hydrogen-bonds. Two cocrystals, namely 2PYTC and 4PYTC were obtained and showed heat-activated emission, and such emission could be quenched or weakened by adding water molecules. The cocrystal structure exhibited the donor molecule that can form multiple hydro bonds with water and acceptor molecules due to the many nitrogen atoms of them. The analyses of the photophysical data, powder X-ray diffraction, and other data confirmed the reversible fluorescence "on-off" effects were caused by eliminating and adding water molecules in the crystal lattice. The density functional theory calculations indicate that the vibration of the O-H bond of water molecules in the cocrystal can absorb the excitation energy and suppress fluorescence. Furthermore, the obtained cocrystals also showed temperature, humidity, and H+ /NH4 + responsive emission behavior, which allows their applications as thermal and humidity sensors, and multiple information encryptions. This research paves the way for preparing intelligent hydrophilic organic cocrystal luminescent materials.

Grinding-induced supramolecular charge-transfer assemblies with switchable vapochromism toward haloalkane isomers

Synthetic macrocycles have proved to be of great application value in functional charge-transfer systems in the solid state in recent years. Here we show a switchable on-off type vapochromic system toward 1-/2-bromoalkane isomers by constructing solid-state charge-transfer complexes between electron-rich perethylated pillar[5]arene and electron-deficient aromatic acceptors including 4-nitrobenzonitrile and 1,4-dinitrobenzene. These charge-transfer complexes with different colors show opposite color changes upon exposure to the vapors of 1-bromoalkanes (fading) and 2-bromoalkanes (deepening). Single-crystal structures incorporating X-ray powder diffraction and spectral analyses demonstrate that this on-off type vapochromic behavior is mainly attributed to the destruction (off) and reconstruction (on) of the charge-transfer interactions between perethylated pillar[5]arene and the acceptors, for which the competitive host-guest binding of 1-bromoalkanes and the solid-state structural transformation triggered by 2-bromoalkanes are respectively responsible. This work provides a simple colorimetric method for distinguishing positional isomers with similar physical and chemical properties.

Monitoring phosphorylation in proteins using a novel technique: Protein charge transfer spectra

Phosphorylation generates tremendous functional diversity, heterogeneity and complexity of the proteome. Therefore, identifying and understanding phosphorylation is critical in the study of cell biology, disease treatment and prevention. Major limitations related to the conventional techniques used to detect phosphorylation are the usage of high-end instruments, invasive nature and labour-intensive protocols. To overcome these limitations, we employed a simpler, cost-effective and non-invasive technique termed Protein Charge Transfer Spectra (ProCharTS). ProCharTS absorption in near UV-Visible region (250-800 nm) is observed when photoinduced electron transfer occurs from HOMO of electron rich DONOR like Glu/phosphate to the LUMO of electron deficient ACCEPTOR like polypeptide backbone species in the protein matrix. Also, ProCharTS luminescence arises subsequent to ProCharTS absorption when charge recombination of the excited state electron occurs with the created hole. Phosphorylation of a protein introduces extra charge and produces change in its conformation/function. The negatively charged phosphate groups are post translationally attached to the otherwise neutral amino acid which then behaves as anions. Since ProCharTS is sensitive to both the charge content and the proximity among charged residues in a protein, any change in either of them will influence ProCharTS. Moreover, recently it has been reported that the simulated absorption spectra of pSer, pThr and pTyr show charge transfer transitions beyond 200 nm. Here we investigate the ProCharTS of two phosphoproteins, α-Casein and β-Casein under various physiological conditions in both phosphorylated and dephosphorylated states. The phosphorylated proteins were dephosphorylated using Alkaline Phosphatase as confirmed with MALDI and SDS-PAGE. We observed changes in the ProCharTS absorbance and luminescence spectra after dephosphorylation. ProCharTS was found to be sensitive to detect the dephosphorylation in proteins. It can be a potential label-free technique to identify phosphorylation state of a protein.

Protein charge transfer spectra in a monomeric protein with no lysine.

UV-Visible absorption and luminescence originating from non-aromatic groups in proteins is being intensely investigated today. Earlier work has shown that non-aromatic charge clusters in a folded monomeric protein can collectively act like a chromophore. Incident light in the near UV-Visible wavelength causes photoinduced electron transfer from the Highest Occupied Molecular Orbital (HOMO) of the electron-rich donor (like a carboxylate anion) to the Lowest Unoccupied Molecular Orbital (LUMO) of the electron-deficient acceptor (like a protonated amine or the polypeptide backbone) in the protein giving rise to absorption spectra in the 250-800 nm range referred to as Protein Charge Transfer Spectra (ProCharTS). The transferred electron can relax back from the LUMO to fill up the hole in the HOMO by a charge recombination process, emitting weak ProCharTS luminescence. Previous studies in monomeric proteins displaying ProCharTS absorption/luminescence always involved lysine-containing proteins. The lysine (Lys) sidechain plays a dominant role in ProCharTS; however, experimental evidence for ProCharTS among proteins/peptides devoid of Lys is lacking. Recently, the absorption features of charged amino acids have been examined using time-dependent density functional theory calculations. In this study, we show that amino acids: arginine (Arg), histidine (His) and aspartate (Asp); homo-polypeptides: poly-arginine and poly-aspartate; and a protein: Symfoil PV2 that is rich in Asp, His and Arg, but lacks Lys, profusely display ProCharTS. The folded Symfoil PV2 protein displayed maximum ProCharTS absorptivity in the near UV-Vis region, in comparison to the homo-polypeptides and amino acids. Furthermore, features like overlapping ProCharTS absorption spectra, decreasing ProCharTS luminescence intensity with longer excitation wavelength, large Stokes shift, multiple excitation bands and multiple luminescence lifetime components appeared to be conserved across peptides, proteins and amino acids studied. Our results underscore the utility of ProCharTS as an intrinsic spectral probe to monitor the structure of any protein that is rich in charged amino acids.

Exploring the photocatalytic activity of synthesized hydrogen bonded charge transfer co-crystal of chloranilic acid with 2-ethylimidazole: DFT, molecular docking and spectrophotometric studies in different solvents

An organic donor (2-ethylimidazole) and an organic acceptor (chloranilic acid) were used to investigate the charge transfer (CT) interaction in polar solvents. Initially, interaction occurs between the electron-rich donor and electron-deficient acceptor through the H-bonding [N+−H····O−], which ultimately results in the formation of CT complex. The CT complex was analyzed using elemental analysis, FTIR, SC-XRD, NMR, UV, and SEM. Based on the results obtained, we concluded that a weaker H-bond is responsible for CT complex formation. The molecular docking study revealed that the CT complex binds precisely and effectively to human serum protein with a free energy value of −8.2 kcal/mol−1. We have further demonstrated the utility of the synthesized complex as an efficient photo-catalyst to degrade methylene blue (MB) and 93% photo-degradation was achieved under UV irradiation for 120 min. Furthermore, the scavenging experiment was performed to determine the mechanism of photo-degradation, which showed the formation of h+ and O2−•as primary active species. DFT calculations using the B3LYP/6-311G++ level of theory were employed.

Highly efficient blue light-emitting polymer containing a Benzo[b]naphtho[1,2-d]thiophene -S,S-dioxide unit

The dibenzothiophene-S,S-dioxide (SO) possess strong but unmatched electron-withdrawing ability when connected to a normally used donor. Here, to lower its electron-withdrawing ability, we synthesized a benzo[b]naphtho[1,2-d]thiophene-S,S-dioxide (NSO) electron-deficient acceptor by using a naphthalene ring to replace one of the benzene rings in the SO unit. The copolymers PPF-NSs and PPF-NSOs were synthesized by introducing the NSO and benzo[b]naphtho[1,2-d] thiophene (NS) unit into polyfluorene backbone. A systematic study was presented based on the copolymers from the aspect of theoretical calculation, photophysical properties, electrochemical properties, and electroluminescent properties. For the PPF-NSs film, intermolecular energy transfer should be the main mechanism of photoluminescence. Whereas, intramolecular charge transfer played the main role in the photoluminescence mechanism for PPF-NSOs film due to the existence of the strong electron-deficient group (NSO). The PPF-NSOs acquired superior blue emission with maximum luminous efficiency (LEmax) of 8.16 cd A−1 and a CIE of (0.16, 0.25) at a low acceptor concentration of 3%, while the copolymer (PPF-NS1) based on energy transfer also achieved a satisfactory performance with LEmax of 5.20 cd A−1 and a CIE of (0.17, 0.18).

A general arene C-H functionalization strategy via electron donor-acceptor complex photoactivation.

The photoactivation of electron donor-acceptor complexes has emerged as a sustainable, selective and versatile strategy for the generation of radical species. However, when it comes to aryl radical formation, this strategy remains hamstrung by the electronic properties of the aromatic radical precursors, and electron-deficient aryl halide acceptors are required. This has prevented the implementation of a general synthetic platform for aryl radical formation. Our study introduces triarylsulfonium salts as acceptors in photoactive electron donor-acceptor complexes, used in combination with catalytic amounts of newly designed amine donors. The sulfonium salt label renders inconsequential the electronic features of the aryl radical precursor and, more importantly, it is installed regioselectively in native aromatic compounds by C-H sulfenylation. Using this general, site-selective aromatic C-H functionalization approach, we developed metal-free protocols for the alkylation and cyanation of arenes, and showcased their application in both the synthesis and the late-stage modification of pharmaceuticals and agrochemicals.

Superior aggregation, morphology and photovoltaic performance enabled by fine tuning of fused electron-deficient units in polymer donors

Copolymerization of an electron-rich donor (D) unit with an electron-deficient acceptor (A) unit to construct efficient D-π-A-π type donors is an effective strategy for organic solar cell applications. The electron-deficient unit fusion, endows extended π-conjugation plane and insures excellent photoelectronic property, has great advantages to build A moiety and gradually receives considerable attention. In this work, we adopt benzo[2,1-b:3,4-b’]dithiophene and benzopyrazine (BP), benzothiadiazole (BT) and benzoselenadiazole (BS) to cleverly construct a series of fused A units with different electron-deficient ability, and further synthesize three polymer donors PBDP-BP, PBDP-BT, and PBDP-BS, respectively. The relationships between structure and performance were systematically investigated. PBDP-BT shows a moderate aggregation behavior in both solution and film, and the highest hole mobility among the three polymers. After blending with Y6, the PBDP-BT:Y6-based film has the strongest absorption, favorable compatibility, superior crystallinity, and uniform phase separation morphology compared with PBDP-BP or PBDP-BS based blend films. Thus, the device based on PBDP-BT:Y6 has the highest and balanced charge mobility, suppressive recombination, reduced energy loss and achieves an outstanding PCE of 15.14%, which is superior to PBDP-BP:Y6 (8.55%) and PBDP-BS:Y6 (6.85%). These results provide learnable guidelines for future fused electron-deficient unit-based donor design for photovoltaic application.

Over 1000 nm photoresponse with cyclopentadithiophene-based non-fullerene acceptors for efficient organic solar cells

Non-fullerene acceptors have a pivotal role in the progress of organic solar cells (OSCs). Though, optical characteristics most of NFAs is quite limited within the range of 600–900 nm, limiting the short-circuit density (Jsc) of the OSCs devices. To address this issue, we have designed nine different C-shaped cyclopentadithiophene (CPDT)-based acceptor–donor-acceptor (A-D-A) structured NFAs for OSCs. To this end, various end-cap functional units have been used to further modify the reference molecule (C0) to improve the optoelectronics and photophysical characteristics of these materials. For this, various advanced quantum mechanical density functional theory (DFT) and time dependent (TD-DFT) approached used to explore the hidden potential of these materials (R, CA1-CA9). The characterizations associated with frontier molecular orbitals (FMOs), transition density Matrix (TDM) analysis, open-circuit voltages (Voc), electron-hole reorganizational energies, fill factor and optical properties of all the investigated molecules are calculated at DFT and TD-DFT-B3LYP/6-31G. In addition to all these calculations the PTB7-Th:C5 complex study (D:A) has also been investigated to check out the charge-transfer from donor polymer (PTB7-Th) to NFA C5 at the D:A interface. The results of these investigations reveal that all the designed A-D-A molecules (C1-C9) with electron-rich core and with electron-deficient end-capped acceptors are perfect for efficient tuning of optical and electrical parameters. With such approach, we can design desired photovoltaic materials by tuning their FMO energy levels, binding energy, and reorganizational energies, Voc, fill factor and absorption maxima characteristics. Therefore, these deigned materials (C1-C9) are highly recommended for synthesis to develop an efficient OSCs. And, this approach could be use effectively to design desire properties materials for the future development of an efficient photovoltaic materials.

Solution-processed AIEgen NIR OLEDs with EQE Approaching 15 .

Organic near-infrared (NIR) luminogens have attracted intensive attention considering their vast potential applications in areas like bioimaging, organic light-emitting diodes (OLEDs) and night-vision telecommunication. However, organic NIR luminogens with high solid quantum efficiencies are scarce, limiting their applications. Here, we reported an electron-deficient acceptor, BSM, based on dithiafulvalene and benzothiadiazole, which could work as a strong acceptor to produce highly efficient NIR emitters with aggregation-induced emission (AIE) property. One of the AIEgens, TBSMCN emitted at 820 nm with a solid quantum yield of 10.7 %. When applied to solution-processed OLEDs, an outstanding external quantum efficiency (EQE) of 9.4 % was achieved with a peak wavelength at 728 nm. Moreover, its non-doped device could achieve an extraordinary EQE of 2.2 % peaking at 804 nm. In the further optimized configuration, when an extra sensitizer was added to harvest triplet excitons, the EQE unprecedentedly soared up to 14.3 % with a peak wavelength of 750 nm.

Fmoc-protected amino acids as luminescent and circularly polarized luminescence materials based on charge transfer interaction

Fluorenylmethyloxycarbonyl (Fmoc)-protected amino acids are effective building blocks in self-assembled architectures at hierarchical levels, which however show limited luminescent properties and chiroptical activities. Here we introduce a charge-transfer strategy to build two-component luminescent materials with emerged circularly polarized luminescence properties. A library of Fmoc-amino acids was built, which selectively form charge-transfer complexes with the electron-deficient acceptor. Embedding in amorphous polymer matrix or physical grinding could trigger the charge-transfer luminescence with adjusted wavelengths in a general manner. X-ray diffraction results suggest the multiple binding modes between donor and acceptor. And, the solution-processed coassembly could selectively exhibit circularly polarized luminescence with high dissymmetry g-factors. This work illustrates a noncovalent charge-transfer strategy to construct luminescent and chiroptical organic composites based on the easy-accessible and economic chiral N-terminal aromatic amino acids.

A class of electron-deficient units: fluorenone imide and its electron-withdrawing group-functionalized derivatives.

This study describes the development of a series of strong electron-deficient acceptor units, namely, fluorenone imide (FOI) and its derivatives, functionalized with various electron-withdrawing groups, which are developed via functionalization of the fluorenone unit with an imide group and then systematic variation of the attached electron-withdrawing groups at the bridgehead benzylic position.

P-Tetrafluorophenylene Divinylene-Bridged Nonfullerene Acceptors as Binary Components or Additives for High-Efficiency Organic Solar Cells

In this study, we designed, synthesized, and characterized an A-D-A'-D-A-type indacenodithienothiophene (IDTT)-based molecular acceptor that exhibited a broader absorption range and higher lowest unoccupied molecular orbital energy level with a nearly comparable band gap compared to a well-known electron acceptor IT-M. The designed electron-deficient molecular acceptor FB-2IDTT-4Cl with a fluorinated benzene tether (FB), that is, p-tetrafluorophenylene divinylene, demonstrated long-wavelength absorption and high hole and electron charge mobility in the thin films blended with the electron donor PBDB-T for an inverted organic photovoltaic (OPV) binary device, resulting in a maximum power conversion efficiency (PCE) of 11.4%. Such a performance is comparably as high as that of the device with PBDB-T:IT-M, and particularly, it was 18.8% higher than that of the devices with ITIC-4Cl as the acceptor (PCE 9.1% ± 0.5%) and 24.9% higher than that of the devices with the thiophene-flanked benzothiadiazole-bridged acceptor CNDTBT-IDTT-FINCN (PCE 9.01% ± 0.13%). Furthermore, varying the illumination intensity from 200 to 2000 lux increased the Jsc and Voc values as well as the FF values, thus leading to increased PCE levels. In addition, the best PCE of the PM6:Y6 device with 1% FB-2IDTT-4Cl as additives was 16.9%. Our stability test showed that the PM6:Y6 standard device efficiency downgraded very soon either at room temperature or under thermal-annealing conditions. However, with the addition of 1% FB-2IDTT-4Cl as additives, the device efficiency still can be maintained at 90-95% in 500 h at room temperature and 95% at 20 h and 85-95% in 45 h at an annealing temperature of 80 °C. These findings demonstrate FB-2IDTT-4Cl to be a promising candidate as an electron acceptor with a fluorinated π-bridging fused-ring design for OPV applications.

Responsive Interfacial Assemblies Based on Charge-Transfer Interactions.

Charge transfer (CT) interactions have been widely used to construct supramolecular systems, such as functional nanostructures and gels. However, to date, there is no report on the generation of CT complexes at the liquid-liquid interface. Here, by using an electron-deficient acceptor dissolved in water and an electron-rich donor dissolved in oil, we present the in situ formation and assembly of CT complex surfactants (CTCSs) at the oil-water interface. With time, CTCSs can assemble into higher-order nanofilms with exceptional mechanical properties, allowing the stabilization of liquids and offering the possibility to structure liquids into nonequilibrium shapes. Moreover, due to the redox-responsiveness of the electron-deficient acceptor, the association and dissociation of CTCSs can be reversibly manipulated in a redox process, leading to the switchable assembly and disassembly of the resultant constructs.

Universal Suzuki-Miyaura Catalyst-Transfer Polymerization for Precision Synthesis of Strong Donor/Acceptor-Based Conjugated Polymers and Their Sequence Engineering.

Catalyst-transfer polymerization has revolutionized the field of polymer synthesis due to its living character, but for a given catalyst system, the polymer scope is rather narrow. Herein we report a highly efficient Suzuki-Miyaura catalyst-transfer polymerization (SCTP) that covers a wide range of monomers from electron-rich (donor, D) to electron-deficient (acceptor, A) (hetero)arenes by rationally designing boronate monomers and using commercially available Buchwald RuPhos and SPhos Pd G3 precatalysts. Initially, we optimized the controlled polymerization of 3,4-propylenedioxythiophene (ProDOT), benzotriazole (BTz), quinoxaline (QX), and 2,3-diphenylquinoxaline (QXPh) by introducing new boronates, such as 4,4,8,8-tetramethyl-1,3,6,2-dioxazaborocane and its N-benzylated derivative, to modulate the reactivity and stability of the monomers. As a result, PProDOT, PBTz, PQX, and PQXPh were prepared with controlled molecular weight and narrow dispersity (Đ < 1.29) in excellent yield (>85%). A detailed investigation of the polymer structures using 1H NMR and MALDI-TOF spectrometry supported the chain-growth mechanism and the high initiation efficiency of the SCTP method. In addition, the use of RuPhos-Pd showing excellent catalyst-transfer ability on both D/A monomers led to unprecedented controlled D-A statistical copolymerization, thereby modulating the HOMO energy level (from -5.11 to -4.80 eV) and band gap energy (from 1.68 to 1.91 eV) of the resulting copolymers. Moreover, to demonstrate the living nature of SCTP, various combinations of D-A and A-A block copolymers (PBTz-b-PProDOT, PQX-b-PProDOT, and PQX-b-PBTz) were successfully prepared by the sequential addition method. Finally, simple but powerful one-shot D-A block copolymerization was achieved by maximizing the rate difference between a fast-propagating pinacol boronate donor and a slow-propagating acceptor to afford well-defined poly(3-hexylthiophene)-b-poly(benzotriazole).

Construction of Novel Polyoxometalate/Perylenediimide Hybrid Heterostructures for Enhanced Photocatalytic Oxidation of Mustard Gas Simulants

Developing and designing novel materials for effective sulfur mustard detoxification are of great importance given their threat to human health. Crystalline donor–acceptor (D–A) hybrid heterostructures as an emerging class of materials are composed of semiconducting organic and inorganic components with enhanced charge-separated properties and thus promising applications in photocatalysis and photovoltaic cells. Herein, we demonstrated that the combination of three perylene diimide derivatives (PDIs) as electron-deficient acceptors with polyoxometalate (POM) anion [SiW12O40]4– as electron-rich donors resulted in three crystalline D–A hybrid heterostructures, namely, (Me4-PDI)2·SiW12O40 (1), (Me4-Br2-PDI)1.5·(HSiW12O40) (2), and (Me4-Cl4-PDI)2·SiW12O40 (3). Due to the considerable electrostatically assisted noncovalent interactions (lone pair−π, π–π, anion−π, and hydrogen-bonding interactions) between electron donors and acceptors, POMs, and PDIs, these hybrids displayed a significant enhancement in the photochemical stability and selective photocatalytic oxidation of the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES).

Single-Molecule White-Light-Emitting Starburst Donor-Acceptor Triphenylamine Derivatives and Their Application as Ratiometric Luminescent Molecular Thermometers.

White-light emission (WLE) from a single molecule is a highly desirable alternative to a complex mixture of complementary colour emitters, which suffers from poor stability and reproducibility for potential use in organic electronic devices and lighting applications. We report single-molecule WLE both in solution and thin films by judiciously controlled π-electron delocalisation between the triarylamine subchromophoric units. Triphenylamine (TPA) forms the central core, and the phenyl rings are substituted with the electron-deficient acceptor 3-ethylrhodanine (Rh) and electron-rich donors triphenylamine or carbazole. The enforced biphenyl configuration of the TPA core and the other donors renders the π-conjugation across the entire chromophore poor, thus the individual subchromophoric units retain their individual emission characteristics, which cover all three primary colour emissions, that is, red, green and blue (RGB). TPA-Rh units exhibit broad fluorescence in the green-red region originating from the local excited (LE) state and intramolecular charge transfer state (ICT), strongly influenced by the solvent, water, and temperature. Different fluorescence parameters, including spectral maxima, ratiometric changes in ICT emission at the expense of blue emission from terminal donor units, and changes in lifetime, have a linear relationship with temperature between 180-330 K, thus the molecules can function as a multiparameter luminescent molecular thermometer. A temperature coefficient of 0.19 K-1 in ratiometric fluorescence changes along with a spectral shift of 0.3 nm K-1 and their workability over the wide temperature makes these molecules promising materials for potential applications. At lower temperatures, individual subchromophoric properties subside because of the reduced dihedral angle of biphenyl, and fluorescence from the whole molecule becomes dominant.