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Anthraimidazoledione-Terpyridine Based Optical Chemosensor for Anions and Cations That Works as Molecular Half-Subtractor, Key-Pad Lock and Memory Device Debiprasad Mondal, Manoranjan Bar, Dinesh Maity, and Sujoy Baitalik J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.5b08337 • Publication Date (Web): 19 Oct 2015 Downloaded from http://pubs.acs.org on October 28, 2015

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The Journal of Physical Chemistry

Anthraimidazoledione-Terpyridine Based Optical Chemosensor for Anions and Cations That Works as Molecular HalfSubtractor, Key-Pad Lock and Memory Device

Debiprasad Mondal, Manoranjan Bar, Dinesh Maity, and Sujoy Baitalik*

Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Kolkata – 700032, India *Corresponding author. E-mail address: [email protected], [email protected]

Telephone Number: 91-033-2414-6666

1

ACS Paragon Plus Environment


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ABSTRACT We designed in this work, a new family of anthraquinone and imidazole functionalized bifunctional

terpyridine

receptor,

2-(4-(2,6-di(pyridine-4-yl)phenyl)-1H-anthra[1,2-

d]imidazole-6,11-dione (tpy-HPhImz-Anq) for recognition and sensing of selective anions and cations as well as for the construction of multifunctional logic devices. The terpyridine motif in the receptor was utilized for cation coordination site and the imidazole moiety as the anion binding site. Both anion and cation recognition aspects of the receptor were thoroughly investigated in acetonitrile, mixed DMSO-water as well as in solid media via different optical channels such as absorption, steady state and timeresolved emission spectroscopic techniques. Based on the absorption and emission spectral responses towards a specific set of ionic inputs, this unique bifunctional receptor can mimic several advanced logic functions such as those of half-subtractor, key-pad lock and memory device. We also report the implementation of fuzzy logic approach to develop an infinite-valued logic system based on the luminescence dependence of the receptor upon concentration of different ionic inputs. In conjunction with the experimental investigation, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) studies were carried out to investigate the structural and electronic properties of the receptor.

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1. INTRODUCTION Designing of molecular systems that are capable for responding to external perturbations such as anionic and cationic inputs are important building blocks for analyte chemosensors and molecular logic devices.1-11 The concept of molecular computing was originated by de Silva et al5 in the year 1993 and since then an enormous efforts have been given by the chemists to design smart functional molecules which can mimic the functions of various fundamental logic gates as well as several high order functions such as half-adder/subtractor,12-16 memory device,1721

key-pad lock,15,22-28 multiplexer/demultiplexer/exciplex29-31 and encoder/decoder,32 which are

unparalleled in silicon-based devices.33,34 To this end, during last few years we are actively involved in designing various molecular systems derived from polypyridine-based ligands functionalized with imidazole and other aromatic hydrocarbons moieties capable of recognizing and sensing selective ionic analytes as well as demonstrating different fundamental and complex logic functions.20,21, 35-39 In this work, we designed a new family of terpyridyl-phenylimidazole receptor directly coupled with anthraquinone moiety, 2-(4-(2,6-di(pyridine-4-yl)phenyl)-1Hanthra[1,2-d]imidazole-6,11-dione (tpy-HPhImz-Anq) for the detection of selective anion and cation as well as for the development of multifunctional logic devices. The interest in studying of anthraquinone derivatives stem from their wide range of realized applications, spanning from their use as dyes and pigments to the biological and medicinal products.40-49 Despite of their important roles as good electron acceptors with desirable thermal and electrochemical stability, relatively little attention has been paid in connection with the development of optoelectronic devices.50-52 Keeping in minds the above-mentioned characteristics and our interest in the development of optical probes for selective anions and cations as well as suitable optoelectronic devices,50-52 we report a new family of imidazoanthraquinone derivative functionalized with phenyl terpyridine unit. Although a few anthraimidazoledione derivatives obtained by linear or angular annulations of different heterocyclic ring to the anthraquinone unit were reported for selective sensing of anions (such as F- and CN-) and cations (such as Fe3+ and Al3+) in solution,17,46-49,53,54 but anthraimidazoledione group coupled with tridentate terpyridine moiety that can lead to complicated and advanced logic operations have never been reported. In a previous communication, we reported a terpyridyl-phenylimidazole system covalently linked to pyrene (tpy-HImzPy) by taking advantage of rich photophysical aspect of pyrene moiety.39 It 3



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was observed that introduction of pyrene moiety leads to generation of an ICT-sensitive receptor whose optical properties was sensitive towards selected ionic inputs. ICT exerts an important role on either a chromogenic or a flurogenic receptor as it leads to shift in its spectral bands. In designing the present receptor, we are interested to modulate the ICT band by incorporating an additional electron accepting anthraquinone moiety to one side of the imidazole moiety which in turn is coupled with another electron accepting terpyridine moiety. Here, the quinone moiety can acts as the additional cation binding site in addition to a terpyridine coordination motif 55. In the present study, we also intended to enhance the acidity of the imidazole NH proton, a well known anion coordination site which interacts with basic anions either by hydrogen bonding interaction or proton transfer by introducing two electron accepting units around it. The possibility of intramolecular hydrogen bonding between the oxygen atom of the quinone moiety and the H atom in the imidazole group could also enhance the acidity of the hydrogen-bond donors. Having in mind these considerations, we report here the synthesis and evaluation of the chemosensory ability of this new anthraimidazoledione-terpyridine system. The present receptor has the ability to act as optical chemosensor for F- and CN-, in acetonitrile as well as in the solid state, whereas as a highly selective chromogenic and fluorogenic receptor for CN- in mixed organic-aqueous medium.4,20,46,49 In addition, the novel system is also capable of visual detection of Fe2+ in presence of other 3d transition metals. It would be of interest to note that the optical response profiles of ICT-sensitive receptor varied quite markedly as a function of ionic inputs and the extent of red-shift of both absorption and emission bands are substantially larger compared with the previously reported pyrenyl-imidazole receptor (tpy-HImzPy). Moreover, compared with tpy-HImzPy, the present dye offers ratiometric fluorescence response towards anions and thus increases the selectivity and the sensitivity of the detection because the ratio of the fluorescent intensities at two wavelengths is independent of the concentration of the sensor, the fluctuation of source-light intensity, and the sensitivity of instrument. Based on the absorption and emission spectral responses, this unique bifunctional receptor can mimic multiple Boolean logic operations (XOR, INHIBIT, IMPLICATION, and NOR) by the influence of specific set of ionic inputs in a systematic manner. More importantly, in contrast to pyrenylimidazole (tpy-HImzPy) system, the present receptor also exhibits rare and advanced logic functions such as those of half-subtractor, key-pad lock and memory device. A half-subtractor is 4


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a combinatorial circuit that subtracts two bits and produces their difference.12-14 It needs two outputs (absorbance at 340 and 477 nm): one generates the difference (D), and the other generates the borrow (B). These outputs are generated through XOR and INHIBIT gates by using F- (input 1) and Zn2+ (input 2) ions, respectively. For the construction of memory devices, reversible and reconfigurable sequential logic operations are essential which are capable of storing information and can be visualized in the form of feedback loop where one of the outputs of the device function serves as the input and is memorized as ‘‘memory element’’. 17-21 As will be demonstrated, the output signals (emission intensity at 607 nm and 528 nm) generated through INHIBIT and IMPLICATION logic gates by the action of F- (input 1) and Zn2+ (input 2) ions leads to the construction of the memory device. Finally, the molecular keypad lock devices which are important for information protection can only be opened by the appropriate combination and sequence of chemical inputs.22-28 The present ditopic receptor could mimic the function of a security keypad lock on sequential addition of Fe2+ (input 1) and Cu2+ (input 2) and monitoring the absorption signal at 576 nm. The function of different logic devices is rely on Boolean logic model which switch between two crisp states, either ‘zero’ or ‘one’ and are very effective in differentiating true and false interactions. But in most of the practical systems, there are some intermediate states which lie in between. The fuzzy logic system (FLS) is thought to be a potential alternative of Boolean logic to characterize the intermediate values between completely true (1) and completely false (0).39,56-62 The motivation behind developing the FLS is based on the notion that human reasoning and decision making process is too complex to be precisely defined and believed to act as automatic fine-tuning control systems that can handle several middle steps with varying degrees of truth. We report herein the implementation of fuzzy logic approach to develop an infinite-valued logic system based on the luminescence dependence of the receptor upon concentration of different ionic inputs. Computational works employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were also carried in this work for better interpretation of the experimentally observed results.

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O N

H N N

O

N N

tpy-HPhImz-Anq

2. RESULTS AND DISCUSSION 2.1. Synthesis and Characterization. Synthesis of the receptor was accomplished by refluxing a 1:1 mixture of 1,2-diaminonanthraquinone and 4′-(p-formylphenyl)-2,2′:6′,2″terpyridine (tpy-PhCHO) in acetic acid medium in presence of excess sodium acetate. The synthesized receptor was characterized by elemental (C, H, N and O) analysis, 1H NMR and ESI mass spectra (Figures S1-S3, SI). 2.2. Electronic Absorption and Emission Spectra. The absorption and emission spectral behaviors of the receptor were investigated at room temperature in three different media viz. acetonitrile, dimethylsulfoxide-water (4:6 v/v) and solid state (Figure 1). As the receptor is insoluble in water, we used 4:6 (v/v) DMSO: H2O mixture for the sensing studies in aqueous medium. In acetonitrile, the receptor exhibits higher energy absorption bands at 282 nm due to ππ* transition, whereas the lowest band at 404 nm is due to intraligand charge transfer (ILCT) transition. The absorption spectral pattern in 4:6 (v/v) DMSO: H2O mixture and in the solid state are basically similar to that of the acetonitrile with little variation in the position of the band maxima and intensities. On excitation to any of the absorption bands, the receptor exhibits strong emission in the wavelength range between 528 nm and 572 nm, depending upon the medium

Figure 1

(Figure 1). The quantum yield increases from DMSO: H2O mixture (Φ = 0.06) to MeCN (Φ = 0.32) and reached the maximum value in the solid state (Φ = 0.40). Finite red-shift of absorption and in particular emission band is found to occur in the solid state, probably due to greater intermolecular interaction in the solid state compared with the solution states.63 In acetonitrile as 6


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well as in the solid state, the receptor exhibits bi-exponential decay profile with lifetimes values of τ1 = 0.25 ns and τ2 = 2.38 ns in acetonitrile and it is too short to be measured accurately in the solid state by using our TCSPC working in the nanosecond domain. By contrast, in 4:6 (v/v) DMSO: H2O mixture, the receptor shows mono-exponential decay profile with lifetime (τ = 4.05 ns) much longer than both acetonitrile and solid media. Red-shift of both absorption and emission band and the enhancement of lifetime of the receptor on changing the solvent from MeCN to 4:6 (v/v) DMSO: H2O mixture suggests the ILCT nature of both the ground and excited states (Figure 1). 2.3. Anion Sensing Studies of the Receptor. As tpy-HPhImz-Anq contains an imidazole NH proton capable of interacting with anions, we will thoroughly investigate its anion recognition and sensing ability in all the three media through different optical channels such as UV-vis absorption, steady state and time-resolved emission spectroscopy. Tetrabutylammonium (TBA) salts of F–, Cl–, Br–, I–, CN–, H2PO4–, AcO–, NO3–, and ClO4- ions were used for the sensing studies. In acetonitrile, among the studied anions, only F– and CN– can cause the red-shift of the lowest energy absorption peak at 404 nm to 480 nm and leads to the quenching of emission band at 528 nm with concomitant appearance of a new and much stronger band at 607 nm (Figure 2). The spectral changes are also visualized by the color change from yellow to orange in normal light and from yellowish green to red under UV illumination (Figure 2). Absorption and emission titration experiments were performed with the selective anions to get quantitative aspects about the interaction between the sensor and the anions. During the course of incremental addition of both F- (Figure 3) and CN- (Figure S4a, SI) ions, the successive absorption curves pass through several well defined isosbestic points with evolution of a new band at 480 nm at the expense of the original band at 404 nm. In the emission titration, the intensity of the original band at 528 nm gradually decreased and at its expense a new emission band at 607 nm was evolved and gradually intensified till 3 equiv of the ions are added (Figure 3b and Figure S4b, SI). During the course of the titration, the successive emission spectrum passes through a nice isoemissive point at 556 nm. The observed ratiometric changes in both absorption and emission spectral profiles can lead to quantify the amount of the anionic species present in the solution. The ratio of emission intensity of the peak at 607 nm to that of 528 nm (I607nm/I528 nm) versus [F-] 7



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Figure 2 Figure 3 or [CN-] plot shows a linear dependence towards F- and CN- within the concentration range of 7 × 10-7 M to 8× 10-6 M (Figure S5, SI). The spectral behaviors of the receptor towards AcO- ion (Figure S6, SI) show the extent of change is much smaller compared with both F– and CN– ions. The excited state lifetimes was measured at both the wavelengths (528 and 607 nm) with incremental addition of F- (Figure 3) and CN- (Figure S4, SI). At both wavelengths, the lifetime value increases, although the extent of increase is higher at 528 nm than at 607 nm. Anioninduced deprotonation of the imidazole NH proton and subsequent delocalization of the negative charge throughout the aromatic frame of tpy-PhImz-Anq probably leads to the stabilization of the emitting excited state and thereby enhance the excited state lifetime. The equilibrium constants for the interaction processes can be calculated from the plots given in the inset of the Figure 3 and Figure S4 (SI) and the values were given in Table 1. The detection limit of tpyHPhImz-Anq was calculated from the titration data and found to lie in the order of 10-7 M for Fand CN- and 10-6 M for AcO- (Figure S7-S12 and Table 1). The mode of interaction can be either

Table 1

through hydrogen bonding interaction between the imidazole N-H proton of the receptor and the anions or due to the anion-induced deprotonation of NH proton. The imidazole N-H first form NH···F- or N-H···CN- type of adduct in presence of F- or CN- ions. In presence of excess anions, the N-H bond finally splits and formed deprotonated species. The similar type of spectral pattern of the receptor in presence of tetrabutylammonium hydroxide (TBAOH) also supports the fact of deprotonation process in presence of F– and CN– (Figure S13, SI). On passing from pure organic to DMSO: H2O (4:6, v/v) medium, the selectivity of tpyHPhImz-Anq is dramatically increased and it responds only to CN-. On addition of ~200 equiv of each of the different anions, the absorption peak at 397 nm gets red-shifted to 471 nm and substantial quenching of emission band 557 nm followed by the increases of band position at 619 nm occurs only in presence of CN- (Figure S14, SI). The spectral changes are also reflected 8


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in the digital photograph of the receptor taken under normal and UV light (Figure 4). The absorption and emission titration profiles of tpy-HPhImz-Anq in mixed organic-aqueous medium differ substantially compared with those in pure acetonitrile medium (Figure 4a,b). We also measured the emission lifetimes by monitoring at two emission wavelengths (557 nm and 619 nm). Incremental addition of CN- leads to substantial enhancement of lifetime (τ = 4.05 ns → τ1= 2.92 ns and τ2 =8.26 ns) at 557 nm, while gradual lowering of lifetime (τ1= 1.68 ns and τ2 = 5.01 ns → τ1= 0.67 ns and τ2 = 3.89 ns) at 619 nm (Figure 4c,d). The calculated values of the

Figure 4 equilibrium constants (Ks = 103 M-1) of the receptor towards CN- ion in mixed DMSO: H2O (4:6, v/v) medium is two order of magnitude less compared to pure acetonitrile (Table 1). The calculated detection limit of the receptor was found to lie in the order of 10-5 M (Table 1 and Figure S15 and S16, SI). The selectivity of the receptor towards CN- over F- and AcO- ions in mixed aqueous-organic media is probably due to greater free energy of hydration for both F(∆Gh°= -465 kJ/mol) and AcO- (∆Gh°= -365 kJ/mol) compared to CN- (∆Gh°= -295 kJ/mol).64 Moreover, greater pKa (9.21) for HCN than HF (pKa = 3.17) and AcOH (pKa =4.76)65 are also responsible for more basic nature of CN- compared with other studied anions in water. The sole selectivity of the receptor towards CN- in presence of other studied anions was also confirmed by UV-vis absorption and emission experiments. The sensing behavior in the solid state was explored by mechanical grinding the receptor with the anions. On grinding the receptor with the TBA salts of different anions in a mortar pestle, an immediate color change is found to occur in presence of CN- and F- ions only (Figure 5a). This color change is also reflected in the UV-vis absorption spectrum where the lowest energy absorption band at 406 nm gets red-shifted to 489 nm (Figure 5b). Similar to absorption spectra, red-shift of the emission band also occurs from 572 nm to 621 nm with concomitant quenching of the original emission at 572 nm (Figure 5c). Excited-state lifetime of the mechanically grinded solid form of the receptor is seen to be considerably smaller than that of free receptor in the solid as well as those of the solution states (Figure S17, SI). Sensitivity towards CN- and F- ions were also examined by grinding a fixed amount of the receptor with 9



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varying crystal size of TBACN. Instant color changes in each case conclude the remarkable sensitivity of the receptor towards F- and CN- in the solid state also. Thus, the receptor is capable of detecting the said anions in real solid sample.

Figure 5

2.4. Cation Binding Studies. Figure 6 shows the absorption and emission spectral changes of tpy-HPhImz-Anq in presence of 0.5 equiv of different metal ions in acetonitrile medium. It is observed that Co2+, Ni2+, Cu2+, Cd2+, Zn2+ and Al3+ leads to the generation of a new band, assignable to ILCT in nature, in the range between 324 nm and 335 nm, while only Fe2+ can lead to the evolution of sharp and intense band at 574 nm, believed to be FeII(dπ) → tpyHPhImz-Anq (π*) MLCT in nature and this spectral change is accompanied by instant color change from pale yellow to deep violet (Figure 6). The assignments of the metal-coordinated lowest energy bands as ILCT and MLCT will also be supported by TD-DFT calculations. Figure 6b shows that the emission intensity of the band at 528 nm decreases in presence of Ni2+, Co2+, Cu2+ and Fe2+, while gets enhanced with small blue-shift in presence of Cd2+, Zn2+, and Al3+, albeit in different extent. Absorption and emission titration experiments of tpy-HPhImz-Anq with incremental addition of metal ions were performed in order to get the quantitative idea of the metal-ligand binding interactions (Figure 7 and Figures S18-S22, SI). Spectral saturation in each case occurs upon addition of 0.5 equiv of metal ion suggesting the formation of [M(tpy-HPhImzAnq)2]n+ type complex (Chart 1). For the confirmation of the composition of the species, the ESI

N N O O

N H

N

Mn+

N

N O O

N

N NM N N N

N H

tpy-HPhImz-Anq Chart 1

O H N N

[M(tpy-HPhImz-Anq)2]n+

Figure 6 Figure 7 10


O

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mass spectra of the receptor were recorded in presence of 0.5 equiv of each of Fe2+ and Cu2+ ion in acetonitrile and the appearance of a signal at m/z = 582.95 and 587.25 with excellent correlation between experimental and simulated isotopic patterns indicate the formation of [Fe(tpy-HPhImz-Anq)2]2+ and [Cu(tpy-HPhImz-Anq)2]2+, respectively (Figure S23 and S24, SI). The emission lifetimes of tpy-HPhImz-Anq were measured upon incremental addition of each of Fe2+, Cu2+ and Zn2+ ions (Figure S25, SI). Surprisingly, the lifetime (bi-exponential decay profiles) of the receptor increases gradually and substantially in each case, albeit in different extent, which is in sharp contrast to that of the steady state emission behavior of the receptor in presence of the said metal ions. Enhancement of the lifetime is probably due to greater delocalization of charge throughout the aromatic frame of the ligand induced by coordination to the metal. The results indicate that the emitting excited state is predominantly ILCT in nature. We are also able to detect Fe2+ ion in the solid state by mechanical grinding the ion with the receptor through intense color change visible with naked eyes. The solid state UV-vis spectra exhibits an intense band at 598 nm which is ~22 nm red-shifted than that in pure acetonitrile. In the emission spectrum, again significant quenching of the band at 571 nm occurs keeping the band position intact (Figure S26, SI). 2.4. DFT and TD-DFT Study. Geometry optimization of tpy-HPhImz-Anq, its NH deprotonated form, tpy-PhImz-Anq and three metal complexes of the form [M(tpy-HPhImzAnq)2]2+, where M = Fe2+, Cu2+, and Zn2+, were done by employing Gaussian 09 program in acetonitrile medium (Figure S27 and S28, SI).66 In both protonated and deprotonated forms, three pyridyl groups adopt usual transoid conformation to minimize the interelectronic repulsions, while in the complexes, the metal is coordinated in bis-tridentate meridional fashion with distorted octahedral geometry (Figure S27 and S28, SI). The metal-nitrogen bond distances lie in the range between 1.906 Å and 2.236 Å and chelate bite angles span in the range between 74.9° and 105.6°, depending slightly on the metal center (Table S1-S2, SI). The central metalnitrogen distance is shorter than that of outer metal-nitrogen bonds in each complex because of the effective overlap between metal t2g and π* orbitals of central pyridine atoms. Frontier molecular orbital sketch indicates that with few exceptions, the HOMOs are mainly localized on the imidazole part of the anthraimidazoledione group, while the LUMOs are localized on either quinone part of anthraimidazoledione group or the tpy moiety (Table 2 and 11



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Figure S29 and S30, SI). The charge distribution in tpy-HPhImz-Anq and tpy-PhImz-Anq can be visualized from their electric surface potential plots (ESP), where the red and blue representing the region negative and positive electrostatic potential, respectively (Figure S31, SI).

Table 2 Among the three complexes, the composition of HOMOs and LUMOs for both Cu2+ and Zn2+ complexes are of similar type, while the compositions differ substantially in Fe2+ complex (Table 2). In case of Cu2+ and Zn2+ complexes, all the four HOMOs are composed predominantly of imidazole moiety of anthraimidazoledione group with some minor contribution of phenyl group of tpy moiety. Among the four LUMOs, first two (LUMO and LUMO+1) mainly composed of quinone part of anthraimidazoledione group, while the next two LUMOs (LUMO+2 and LUMO+3) mainly composed of tpy moiety (Table 2 and Figure S32-S33, SI). In contrast to Cu2+ and Zn2+ complexes, all the four HOMOs in the Fe2+ complex are mainly composed of Fe (II) ion, with some contribution from tpy moiety, while the LUMOs are similar to that of Cu2+ and Zn2+ complexes (Table 2 and Figure S33, SI). TD-DFT computations were performed on the optimized structures of the compounds in acetonitrile to obtain their theoretical UV-vis spectra (Table 3). In general the agreement between the experimental and calculated data is quite good (Figure 8). The involvement of the molecular orbitals to the lowest energy transition of all the compounds is portrayed in Figure 9. The calculated band at 437 nm for tpy-HPhImz-Anq can be assigned as ILCT from the phenylimidazole part to the quinone part of anthraimidazoledione moiety, while the band 326 nm as a combination of the ILCT and π-π* transitions localized on anthraimidazoledione and tpy moieties. The corresponding experimental values are 404 nm and 290 nm which are typically within the error of TD-DFT calculations. In addition, the experimentally observed red-shift of the absorption bands, in particular the lower energy ILCT bands on NH deprotonation can also be predicted by the computational results.

Table 3 Figure 8 12


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Figure 9 The calculated lowest energy absorption band for both Zn2+ and Cu2+ complexes is the same (452 nm) and assigned as ILCT from phenyl-imidazole to anthraquinone moiety, while the next higher energy band at 373 nm for Zn2+ and 379 nm for Cu2+ is due to phenyl-imidazole to tpy ILCT. Thus, the experimentally observed bands at 401 nm and 327 nm for Zn2+and 401 nm and 335 nm for Cu2+ arise due to respective ILCTs. In contrast to both Zn2+ and Cu2+ complexes, experimentally observed lowest energy band at 575 nm for Fe(II) complex is due to MLCT (FeII to the quinone moiety of anthraimidazoledione). In order to take into account the emission characteristics of the compounds, we optimized the geometries of tpy-HPhImz-Anq, tpy-PhImz-Anq and [Zn(tpy-HPhImz-Anq)2]2+ in their lowest singlet (S1) excited states by TD-DFT methodology (Table S3 and Figures S27-S30 and S32-S33, SI). Taking into account the involvement of MOs, the emission process in the compounds is ascribed due to the ILCT from the anthraquinone part to the pheny-imidazole moiety of tpy-HPhImz-Anq (Figure S34, SI). Calculated emission bands at 528 and 627 nm and 511 nm that are found for tpy-HPhImz-Anq, tpy-PhImz-Anq and [Zn(tpy-HPhImz-Anq)2]2+, respectively correlate remarkably well with the corresponding experimental values (528 and 607 nm and 516 nm) (Table S4, SI). Again, the shift of emission maximum towards longer wavelength on deprotonation of the imidazole NH proton of the receptor has been taken into account by the TD-DFT calculations. 2.5. Molecular Logic Devices 2.5.1. Half-Subtractor. A half-subtractor is a combination of two different circuits that subtracts two bits and produces their difference: one generates the difference (D), and the other generates the borrow (B). In this particular case, the two outputs are the absorbance at 340 and 477 nm modulated by the action of two inputs: F- (input 1) and Zn2+ (input 2) ions, respectively. These two outputs are generated through XOR and INHIBIT logic gates. With these considerations in mind, we developed a binary half-subtractor. In presence of both the chemical inputs, the absorption spectrum of the receptor changes considerably and by monitoring the absorbance at two different wavelengths (340 nm and 477 nm), we are able to design two logic gates: XOR and INHIBIT. In case of XOR logic gate, the output signal at 340 nm become active 13



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(1) in presence of any one of the inputs and become deactivated (0) either in presence or absence of the both the inputs. Similarly in case of INHIBIT logic gate, the output signal at 477 nm become activated (1) in presence of only input1 and for the other three combinations, the output signal become deactivated (0). Thus, by combining the functions of both XOR and INHIBIT logic gates, we can easily construct the mimic of a half-subtractor as demonstrated in Figure10.

Figure 10

2.5.2. Key-Pad Lock. Molecular keypad locks protect information at the molecular level by creating a secret password and thus play vital roles in information security. To mimic the function of a key-pad lock, the absorption intensity of tpy-HPhImz-Anq at 576 nm has been utilized as the output signal which is a delicate function of two cationic inputs (Fe2+ and Cu2+) used in this particular case. It is important to note that maintaining of proper sequence for the addition of said ions is essential for developing a security keypad lock. As illustrated in Figure 11, the input Fe2+ ion is designated as “A”, while input Cu2+ is designated “R”. Likewise “onstate” and “off-state” is designated as “T’ and “M”, respectively. In the absence of any of two ionic inputs, there is no detectable absorbance at 576 nm which indicates “off-state”. Addition of “A” followed by “R” can give rise to a high absorbance values corresponding to the “on-state” of the system and thereby creates a secret password “ART”. By contrast, reversing of the sequence (“R” followed by “A”) leads to decrease of the absorbance below threshold limit indicating the “off-state” of the system and the password generated by this sequence is “RAM”. Thus, this sequence failed to open the keypad lock because of wrong entry “RAM”. Therefore, the sequence dependent inputs are essential for the construction of the molecular keypad lock i.e. ‘ART’ only in the present system. This observation indicates that only the authorized user who knows the exact password “ART” can open the lock and it is a new approach for protecting information at the molecular scale. When the numerical digits (0-9) are used as PIN numbers in a two-digit password, a total of 90 different combinations are allowed, while choice increases up to 650 different combinations when individual letters (A–Z), each signifying a specific ionic input, are used as PIN numbers. Thus, the cracking of the keypad lock becomes more difficult and thereby improved the security of the molecular devices remarkably. Moreover it is important to 14


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mention that the present molecular level security device has advantages in the fact that it is easy to detect Fe2+and Cu2+ by naked eye by their visual color changes.

Figure 11

2.5.3. Combination of INHIBIT and IMPLICATION Logic Gates Leads to the Construction of Memory Device. As mentioned in the previous section, addition of F- ion leads to quenching of the emission band of the receptor at 528 nm with simultaneous emergence of a much enhanced new emission band at 607 nm. On the other hand, addition of Zn2+ ion leads to enhancement of the original band at 528 nm with small blue-shift to 516 nm. Thus, addition of both F- and Zn2+ ions leads to turn-on the emission of the receptor but at different wavelengths. By maintaining proper sequence of the addition of these two inputs, F– (input 1) and Zn2+ (input 2) and monitoring the output emission signals at 607 nm and 528 nm, it is possible to mimic the functions of INHIBIT and IMPLICATION logic gates. High emission intensity at the said wavelengths corresponds to the on-state (1), while low intensity below the threshold value corresponds to off-state (0) of the system. When both of the inputs (F– or Zn2+) are absent, the output at 607 nm is low indicating the off-state (0) of the system. In presence of Input 1, significant enhancement of emission occurs implying the on-state (1) of the system, while in presence of input 2, the emission is very low indicating off-state (0) of the system. These combinations lead to the construction of INHIBIT logic gate (Figure 12). By using the same inputs, IMPLICATION logic gate can be constructed by monitoring the output signal 528 nm. In absence of any of the chemical inputs, free receptor shows intense emission at 528 nm and corresponds to the on-state (1). By contrast, addition of input 1 leads to almost complete quenching of emission and thus corresponds to the off-state (0). Now, the presence of either input 2 or both leads to activate the signal at 528 nm and again imply the on-state (1) of the system. These combinations lead to the construction of the IMPLICATION logic gate (Figure 12). Figure 12

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Thus, the above logic operations indicate that INHIBIT logic output is complementary to an IMPLICATION gate which is equivalent to the IF-THEN and NOT operations. For the construction of memory devices which are capable of storing information, the sequential logic circuits are essential. It operates through the feedback loop in which one of the outputs of the memory device serves as the input and is memorized as ‘‘memory element’’. Thus, according to above observations, we were able to design sequential logic circuit displaying ‘‘Write–Read– Erase–Read’’ with the help of binary logic. In our system, the on-state (1) corresponds to the strong emission output signal at 607 nm, whereas the off-state (0) corresponds to very weak emission signal at the same wavelength. Here the chemical inputs F- and Zn2+ are designated as input 1 and input 2 for Set (S) and Reset (R) process. When the Set (S=1) inputs is high, the system writes and memorizes the binary state ‘‘1’’. This memorized information is erased by the use of Reset input (R) resulting the written and memorized of binary state ‘‘0’’. This type of reversible reconfigurable sequences of Set/Reset logic operations constructed feedback can be represented in the form of a feedback loop, which demonstrates the memory feature with ‘‘Write–Read–Erase–Read” function with the emission signal at 607 nm (Figure 13). The interesting part is that this ‘‘Write–Read–Erase–Read” loop can be repeated many time.

Figure 13

It is of interest to note interactions between tpy-HPhImz-Anq and anions or cations are reversible. After complexation of tpy-HPhImz-Anq with cations or anions, the restoration of the initial state of tpy-HPhImz-Anq is possible. Moreover, the functions of different logic gates displayed by the receptor is based upon the strategy of coordination of metal ions (Fe2+ or Zn2+) to the terpyridine moiety of tpy-HPhImz-Anq followed by their reversible decomplexation by Fion. Figure S35 and S36 (SI) show the absorption and fluorescence spectral changes of [Fe(tpyHPhImz-Anq)2]2+ and [Zn(tpy-HPhImz-Anq)2]2+ as a function of F- ion. Two-step changes are observed in the spectra of both complexes. Addition of F- up to 3 equiv give rise to the deprotonation of the imidazole NH protons in the complexes in the first step and addition of excess anions (up to 8.0 equiv) give rise to decoordination of metals (Fe2+ or Zn2+) from [M(tpyHPhImz-Anq)2]2+ in the second step leading to the regeneration of free tpy-PhImz-Anq and 16


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stable fluoride complexes of the metals. In the second category experiment, we performed the titrations of tpy-HPhImz-Anq with Fe2+ in the presence of excess F- ion (Figure S37, SI). Thus, the reversibility of the spectral responses towards successive coordination by metal ions and decoordination by F- was observed and as a result the functions of half-substractor and memory device displayed by the receptor can be repeated many times (Figure S38, SI). 2.5.4. Three Input NOR Logic Gate. Thus far, we demonstrated several advanced logic functions exhibited by the receptor by using two ionic inputs. Now, based on the florescence response profiles (λem= 528 nm) of tpy-HPhImz-Anq upon action of three cationic inputs (Cu2+, Co2+, and Ni2+), the function of NOR logic gate can be mimicked. NOR logic gate attracts special attention because it is believed to be the universal logic gate that is capable to connect with other logic operations leading to the combinatorial creation of all other Boolean operations. Figure S39 (SI) shows the histogram and truth table upon sequential action of Cu2+, Co2+, and Ni2+ on the florescence behavior of receptor leading to the construction of three inputs NOR logic gate. 2.6. Multivalued Logic with Fuzzy Interference System. Due to the vague nature of chemical reactions, the Fuzzy logic computing is thought to be a potential alternative to address the uncertain information in the analogue region in Boolean logic system.39,56-62 In the absence of exact values of the variables, one can express the variable in terms of a few linguistic values such as low, medium, or high. Figure 14 represents how the input (Cu2+) and output (emission quantum yield, Φ) variables can be expressed in terms of fuzzy sets. A compilation of different IF-THEN statements which comprises the inference rules is given in the red box of Figure 14. The IF-part corresponds to the antecedent, while the THEN-part corresponds to the consequence. The inference engine of the FLS is capable of mapping out the input fuzzy sets into the output fuzzy sets. The defuzzifier is then capable of converting the output fuzzy sets into crisp numbers. The output crisp number plays the important role of predicting variable such as quantum yield (Φ). In a similar way, the input (Fe2+) and output (emission quantum yield, Φ) variables can be expressed in terms of fuzzy logic (Figure S40, S I).

Figure 14

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Addition of Fe2+ leads to quench the emission intensity of tpy-HPhImz-Anq, while simultaneous addition of both Fe2+ and F – may lead to either increase or decrease of emission intensity. Thus, tpy-HPhImz-Anq can be subjected to implement fuzzy logic functions with varying amount of Fe2+ and F- as the inputs and fluorescence quantum yield as the outputs (Table S5, SI). In FLS, the rules are “IF…, THEN…” statements with multiple antecedents involving the OR, and AND operators. Probable combinations of Fe2+ and F- can give rise to thirteen rules (Table S6, SI). The molar ratio of input and tpy-HPhImz-Anq (nFe2+/ntpy-HPhImz-Anq and nF-/ntpyHPhImz-Anq)

can be decomposed into three fuzzy sets: (1) low (µL), whose symbol is zmf, (2)

medium (µM) with symbol trimf, and (3) high (µH) with symbol smf. Likewise, ΦF (output variable) is spread into three fuzzy sets: (1) low with a zmf µL, (2) medium with a trimf µM, and (3) high with a smf µH. Now we will implement Mamdani’s FLS fuzzy rules.67,68 Dual antecedents are joined by the OR and AND operators because of the synergetic action of the inputs. Table S6 (SI) lists all the fuzzy rules. Moreover, the variations of emission quantum yield (ΦF) as a function of both inputs (Fe2+ and F-) is shown in a three-dimensional representation (Figure 15). Figure 15

3. CONCLUSIONS In our endeavor to construct suitable optical chemosensors that can lead to mimic sequential advanced logic function, we designed in this work a new family of anthraquinone and imidazole functionalized terpyridine receptor (tpy-HPhImz-Anq). The terpyridine motif was utilized for cation coordination site and the imidazole moiety as the anion binding site. Furthermore, angular annulation of the anthraquinone unit into the phenyl terpyridine moiety leads to the generation of an ICT-sensitive sensor whose optical properties are very much sensitive to selected anions and cations. Both anion and cation recognition properties of the receptor were also investigated in acetonitrile, mixed DMSO-water as well as in solid media via different optical channels such as absorption, steady state and time-resolved emission spectroscopic techniques. In conjunction with the experimental investigation, DFT and TD-DFT studies were carried out to investigate the structural and electronic properties of the receptor. Based on the absorption and emission spectral 18


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responses towards a specific set of ionic inputs, this unique bifunctional receptor can mimic several advanced logic functions such as those of half-subtractor, key-pad lock and memory device. Moreover, implementation of fuzzy logic approach was adopted to develop an infinitevalued logic system to characterize the imprecise values between completely true (1) and completely false (0). Thus, implementation of a binary and a multivalued fuzzy logic within a single molecule makes it a potential candidate for versatile use in molecular computing.

4. Experimental Section 4.1. Materials. 1, 2-diaminonanthraquinone, tetrabutylammonium (TBA) salts of the anions and perchlorate salts of the cations were purchased from Sigma-Aldrich. Other reagents and solvents were procured from local vendors and used without further purification. 4′-formyl2, 2′:6′, 2″ terpyridine (tpy-PhCHO) was synthesized by following the literature procedure.69 4.2. Synthesis of 2-(4-(2,6-di(pyridine-4-yl)phenyl)-1H-anthra[1,2-d]imidazole-6,11dione (tpy-HPhImz-Anq). Synthesis of the ligand were carried out by refluxing a mixture of 1, 2-diaminonanthraquinone (0.238 g, 1.0 mmol), 4′-(p-formylphenyl)-2,2′:6′,2″-terpyridine (tpyPhCHO) (0.337 mg , 1.0 mmol), and NaOAc (0.544 g, 4.0 mmol) in 25 mL AcOH for 4 h. After cooling, the reaction mixture was poured slowly into ice-cooled water and resulted suspension was neutralized with a saturated solution of Na2CO3. A yellowish brown colored that appeared was collected through filtration and washed with water for removing excess Na2CO3. Finally the compound was recrystallized from chloroform-methanol (1:1 v/v) mixture. Yield, 0.410 g, 74%. Anal. Calcd for C36H21N5O2: C, 77.83; H, 3.78; N, 12.61; O, 5.76 Found: C, 77.85; H, 3.8; N, 12.63; O, 5.74. 1H NMR (300 MHz, DMSO–d6, δ / ppm): 13.41 (s, 1H, NH imidazole), 8.82 (s, 2H, H3ʹ), 8.79 (d, 2H, J=4.2,H6), 8.69(d, 2H, J=7.6 ,H3), 8.62(d, 2H, J =8.4 H8), 8.17-8.11(m, 2H, H9+H10), 8.07- 8.02 (m, 4H, H4+H7) , 7.85-7.74 (m, 4H, H11+H12), 7.54 (t, 2H, J=5.8, H5). 4.3. Physical measurements. Description of different physical measurements and theoretical calculation methods were provided in the experimental section of the Supporting Information. ACKNOWLEDGEMENT. We gratefully acknowledge the financial support received from the Council of Scientific and Industrial Research New Delhi, India through the project 19



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[Grant No. 01(2766)/13/EMR-II]. Thanks are due to the DST for providing Time-Resolved Nanosecond Spectrofluorimeter in PURSE programme at Department of Chemistry of Jadavpur University. D. M acknowledges CSIR, New Delhi and M. B acknowledges UGC, New Delhi for their fellowship. Supporting Information Available: UV-vis absorption, steady state and time-resolved luminescence spectra, and molecular orbital pictures spectra related to DFT and TD-DFT calculation. This material is available free of charge via the Internet at http://pubs.acs.org

References (1) Schraderr, T.; Hamilton, A. D. Functional synthetic receptors, Wiley-VCH: Weinheim, Germany, 2005. (2) de Silva, A. P.; Gunaratne, H. Q. N.; Gunnlaugsson, T. A.; Huxley, J. M.; McCoy, C. P.; Rademacher, J. T.; Rice, T. E. Signaling recognition events with fluorescent sensors and switches. Chem. Rev. 1997, 97, 1515-1566. (3) Sessler, J. L.; Gale, P. A.; Cho, W. S. Anion receptor chemistry, Royal Society of Chemistry: U.K., 2006. (4) Wang, F.; Wang, Li; Chen, X.; Yoon, J. Recent progress in the development of fluoremetric and colorimetric chemosensors for detection of cyanide ions. Chem. Soc. Rev. 2014, 43, 4312-4324 (5) de silva, A. P.; Gunaratne, H. Q. N.; McCoy, C. P. A molecular photoionic AND gate based on fluorescent signalling. Nature, 1993, 364, 42-44. (6) Andréasson, J.; Pischel, U. Molecules with a sense of logic: a progress report. Chem. Soc. Rev. 2015, 44, 1053-1069. (7) Daly, B.; Ling, J.; de Silva, A. P. Current developments in fluorescent PET (photoinduced electron transfer) sensors and switches. Chem. Soc. Rev. 2015, 44, 42034211. (8) Molecular and Supramolecular information processing, Katz, E., Ed., Wiley-VCH, Weinheim, 2012. (9) de Silva, A. P. Molecular logic gate arrays. Chem. Asian J. 2011, 6, 750-766.

20


Page 21 of 45

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(10) de Ruiter, G.; van der Boom, M. E. Surface-confined assemblies and polymers for molecular logic. Acc. Chem. Res. 2011, 44, 563-573. (11) Ball, P. Chemistry meets computing. Nature. 2000, 406, 118-120. (12) Suresh, M.; Jose, D. A.; Das, A. [2,2′-Bipyridyl]-3,3′-diol as a molecular half-subtractor. Org. Lett. 2007, 9, 441-444. (13) Coskun, A.; Deniz, E.; Akkaya, E. U. Effective PET and ICT switching of boradiazaindacene emission: a unimolecular, emission-mode, molecular half-subtractor with reconfigurable logic gate. Org. Lett. 2005, 7, 5187-5189. (14) Langford,

S.

J.;

Yann,

T.

Molecular

logic:

a

half-subtractor

based

on

tetraphenylporphyrin. J. Am. Chem. Soc. 2003, 125, 11198-11199. (15) Kumar, S.; Luxami V.; Saini, R.; Kaur, D. Superimposed molecular keypad lock and half-subtractor implications in a single fluorophore. Chem. Commun. 2009, 3044-3046. (16) Margulies, D.; Melman, G.; Shanzer, A. Molecular full-adder and full-subtractor, an additional step toward a moleculator. J. Am. Chem. Soc. 2006, 128, 4865-4871. (17) Kaur, N.; Kumar, S. Aminoanthraquinone-based chemosensors: colorimetric molecular logic mimicking molecular trafficking and a set–reset memorized device. Dalton Trans. 2012, 41, 5217-5224. (18) MacVittie, K.; Halamek, J.; Katz, E. Enzyme-based D-flip-flop memory system Chem. Commun. 2012, 48, 11742-11744. (19) Zhuang, H.; Zhou, Q.; Zhang, Q.; Li, H.; Li, N.; Xu, Q.; Lu, J. Effects of aromatic spacers on film morphology and device memory performance based on imidazole- πtriphenylamine derivatives. J. Mater. Chem. C, 2015, 3, 416-422. (20) Mardanya, S.; Karmakar, S.; Mondal, D.; Baitalik, S. An imidazolyl-pyreno-imidazole conjugate as a cyanide sensor and a set–reset memorized sequential logic device, Dalton Trans, 2015, 44, 15994-16012. (21) Karmakar, S.; Mardanya, S.; Das, S.; Baitalik, S. Efficient deep-blue emittier and molecular-scale

memory

device

based

on

dipyridyl-phenylimidazole-terpyridine

assembly. J. Phys. Chem. C. 2015, 119, 6793-6805. (22) Andrasson, J.; Straight, S. Moore, D. T.; Moore, A.; Gust, D. An all-photonic molecular keypad lock. Chem. Eur. J. 2009, 15, 3936-3939. 21



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 22 of 45

(23) Margulies, D.; Felder, C. E.; Melman, G.; Shanzer, A. A molecular keypad lock: a photochemical device capable of authorizing password entries. J. Am. Chem. Soc. 2007, 129, 347-354. (24) Guo, Z.; Zhu, W.; Shen L.; Tian, H. A fluorophore capable of crossword puzzles and logic memory. Angew. Chem. Int. Ed. 2007, 46, 5549-5553. (25) Bhalla, V.; Roopa; Kumar, M. Fluoride triggered fluorescence “turn on” sensor for Zn2+ ions based on pentaquinone scaffold that works as a molecular keypad lock. Org. Lett. 2012, 14, 2802-2805. (26) Zou, Qi.; Li, X.; Zhang, J.; Zhou, J.; Sun, B.; Tian, H. Unsymmetrical diarylethenes as molecular keypad locks with tunable photochromism and flurescence via Cu2+ and CNcoordinations. Chem. Commun. 2012, 48, 2095-2097. (27) Carvalho, C. P.; Domınguez, Z.; Da Silva, J. P.; Pischel, U. A supramolecular keypad lock. Chem. Commun. 2015, 51, 2698-2701. (28) Jiang, X.-J.; Ng, D. K. P. Sequential logic operations with a molecular keypad lock with four inputs and dual fluorescence outputs. Angew. Chem. 2014, 126, 10649 -10652. (29) Andrasson, J.; Straight,S. D.; Bandyopadhyay, S.; Mitchell, R. H.; Moore, T. A.; Moore, A. L.; Gust, D. Molecular 2:1 digital multiplexer. Angew. Chem. Int. Ed. 2007, 46, 958961. (30) Erbas-Cakmak, S.; Bozdemir, O. A.; Cakmak, Y.; Akkaya, E. U.; Proof of principle for a molecular 1 : 2 demultiplexer to function as an autonomously switching theranostic device . Chem. Sci. 2013, 4, 858-862. (31) Xu, S.; Hao, Y.-X.; Sun, W.; Fang, C.-J.; Lu, X.; Li, M.-N.; Zhao, M.; Peng, S.-Q.; Yan C.H. 2:1 Multiplexing function in a simple molecular system. Sensors. 2012, 12, 44214430. (32) Andreasson, J.; Pischel, U. Smart molecules at work-mimicking advanced logic operations. Chem. Soc. Rev. 2010, 39, 174-188. (33) Guliyev, R.; Ozturk, S.; Kostereli, Z.; Akkaya, E. U. From virtual to physical: integration of chemical logic gates. Angew. Chem. Int. Ed. 2011, 50, 9826-9831. (34) Gupta, T.; van der Boom, M. E. Redox-active monolayers as a versatile platform for integrating boolean logic gates. Angew. Chem. Int. Ed. 2008, 47, 5322-5326. 22


Page 23 of 45

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(35) Das, S.; Karmakar, S.; Saha, D.; Baitalik, S. A combined experimental and DFT/TD-DFT investigation of structural, electronic, and cation-induced switching of photophysical properties of bimetallic Ru(II) and Os(II) complexes derived from imidazole-4,5dicarboxylic acid and 2,2′-bipyridine. Inorg. Chem. 2013, 52, 6860-6879. (36) Das, S.; Karmakar, S.; Mardanya. S.; Baitalik, S. Synthesis, structural characterization, and multichannel anion and cation sensing studies of a bifunctional Ru(II) polypyridyl– imidazole based receptor. Dalton Trans. 2014, 43, 3767-3782. (37) Maity, D.; Bhaumik,C.; Mondal, D.; Baitalik, S. Ru(II) and Os(II) Complexes based on terpyridyl-imidazole ligand rigidly linked to pyrene: synthesis, structure, photophysics, plectrochemistry, and anion-sensing studies. Inorg. Chem. 2013, 52, 13941-13955. (38) Mardanya, S.; Karmakar, S.; Das, S.; Baitalik, S. Anion and cation triggered modulation of optical properties of a pyridyl-imidazole receptor rigidly linked to pyrene and construction of INHIBIT, OR and XOR molecular logic gates: a combined experimental and DFT/TD-DFT investigation. Sensors and Actuators B. 2015, 206, 701-713. (39) Karmakar, S.; Maity, D.; Mardanya, S.; Baitalik, S. Demonstration of multiple logic operations in a heteroditopic pyrene−phenylimidazole−terpyridine conjugate based on optical responses by selective anions and cations: An experimental and theoretical investigation. J. Phys. Chem. A. 2014, 118, 9397-9410. (40) Zubay, G. L.; Brown, Wm. C.; Biochemistry, Dubuque, IA, 4th Ed. 1998. (41) Langdon-Jones, E. E.; Pope, S. J. A. The coordination chemistry of substituted anthraquinones: developments and applications. Coordination Chemistry Reviews 2014, 269, 32-53. (42) Ng, T.B.; Liu, F.; Lua,Y.; Chenga, C.H.K.; Wang, Z. Antioxidant activity of compounds from the medicinal herb aster tataricus. Comparative Biochemistry and Physiology Part C. 2003, 136, 109-115. (43) Liua, Q.;

Kima, S. B.; Ahna, J. H.;

Hwanga, B. Y.; Kim, S. Y.;

Lee, M. K.

Anthraquinones from morinda officinalis roots enhance adipocyte differentiation in 3T3L1 cells . Natural Product Research. 2012, 26, 1750-1754.

23



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 45

(44) Shrestha, J. P.; Fosso, M. Y.; Bearss, J.; Chang, C.-W. T. Synthesis and anticancer structure activity relationship investigation of cationic anthraquinone analogs. European Journal of Medicinal Chemistry. 2014, 77, 96-102. (45) Stathopouloua, K. ; Valianoub, L.; Skaltsounisa, A.- L.; Karapanagiotis, I.; Magiatisa, P. Structure elucidation and chromatographic identification of anthraquinone components of cochineal (dactylopius coccus) detected in historical objects. Analytica Chimica Acta 2013, 804, 264-272. (46) Saha, S.; Ghosh, A.; Mahato, P.; Mishra, S.; Mishra, S. K.; Suresh, E.; Das, S.; Das, A. Specific recognition and sensing of CN- in sodium cyanide solution. Org. Lett. 2010, 12, 3406-3409. (47) Marín-Hernández, C. C.; Santos-Figueroa, L. E.; Moragues, M. E.; Raposo, M. M. M.; Batista, R. M. F.; Costa, S. P. G.; Pardo, T.; Martínez-Máñez, R.; Sancenón F. Imidazoanthraquinone derivatives for the chromofluorogenic sensing of basic anions and trivalent metal. J. Org. Chem. 2014, 79, 10752-10761. (48) Kumari, N.; Jha, S.; Bhattachary S. Colorimetric probes based on anthraimidazolediones for selective sensing of fluoride and cyanide ion via intramolecular charge transfer. J. Org. Chem. 2011, 76, 8215-8222. (49) Batistaa, R. M.F.; Oliveirab, E.; Costa, S. P.G.; Lodeirob, C.; Raposo, M. M. M. Cyanide and fluoride colorimetric sensing by novel imidazo-anthraquinones functionalised with indole and carbazole. Supramolecular Chemistry 2014, 26, 71–80. (50) Zhu, H.; Yang, Y.; Hyeon-Deuk, K.; Califano, M.; Song, N.; Wang, Y.; Zhang, W.; Prezhdo, O. V.; Lian, T. Auger-assisted electron transfer from photoexcited semiconductor quantum dots. Nano Lett. 2014, 14, 1263-1269. (51) Rabache,V.; Chaste, J.; Petit, P.; Rocca, M. L. D.; Martin, P.; Lacroix, J.- C.; McCreery, R. L.;

Lafarge, P. Direct observation of large quantum interference effect in

anthraquinone solid-State junctions. J. Am. Chem. Soc. 2013, 135, 10218-10221. (52) Darwish, N.; Diez-Prez, I. ; Da Silva, P.; Tao, N.; Gooding, J. J. ; Paddon-Row M. N. Observation of electrochemically controlled quantum interference in a single anthraquinone-based norbornylogous bridge molecule. Angew. Chem. Int. Ed. 2012, 51, 3203- 3206. 24


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(53) Peng, X.; Wu, Y.; Fan, J.; Tian, M.; Keli, H. Colorimetric and ratiometric fluorescence sensing of fluoride: tuning selectivity in proton transfer. J. Org. Chem. 2005, 70, 1052410531. (54) Batista, R. M. F.; Costa, S. P.G.; Raposo M. M. M. Selective colorimetric and fluorimetric detection of cyanide in aqueous solution using novel heterocyclic imidazoanthraquinones. Sensors and Actuators B. 2014, 191, 791- 799. (55) Constable, E. C. 2, 2′: 6′, 2″-terpyridines: From chemical obscurity to common supramolecular motifs. Chem. Soc. Rev. 2007, 36, 246-253. (56) Gentili, P. L. The fundamental fuzzy logic operators and some complex boolean logic circuits implemented by the chromogenism of a spirooxazinew. Phys. Chem. Chem. Phys. 2011, 13, 20335-20344. (57) Gentili, P. L. Boolean and fuzzy logic gates based on the interaction of flindersine with bovine serum albumin and tryptophan. J. Phys. Chem. A 2008, 112, 11992-11997. (58) Gentili, P. L. Molecular processors: from qubits to fuzzy logic. Chem Phys Chem. 2011, 12,739-745. (59) Gentili, P. L.; Gotoda, H.; Dolnik, M.; Epstein, I. R. Analysis and prediction of a periodic hydrodynamic oscillatory time series by feed-forward neural networks, fuzzy logic, and a local nonlinear predictor Chaos 2015, DOI: 10.1063/1.4905458. (60) Gentili, P. L. The fuzziness of a chromogenic spirooxazine. Dyes and Pigments. 2014, 110, 235-248. (61) Bavireddi, H.; Bharatez, P.; Kikkeri, R. Use of Boolean and fuzzy logics in lactose glycocluster research. Chem. Commun. 2013, 49, 9185-9187. (62) Sahu, S., Sil, T. B.; Das, M.; Krishnamoorthy, G. A single fluorophore to address multiple logic gates, Analyst, 2015, 140, 6114-6123. (63) Fu, G.-L.; Pan, H. Zhao Y.-H.; Zhao, C.-H. Solid-state emissive triarylborane-based BODIPY dyes: Photophysical properties and fluorescent sensing for fluoride and cyanide ions. Org. Bio. Chem. 2011, 9, 8141-8146. (64) Marcus, Y. Thermodynamics of Solvation of Ions. J. Chem. Soc. Faraday Trans. 1991, 87, 2995-2999. (65) Lide, D. R. Handbook of chemistry and physics, 84th ed., CRC press, 2003-2004. 25



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(66) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A. et al. Gaussian 09, revision A.02; Gaussian Inc.: Wallingford, CT, 2009 (67) Zadeh, L. A. IEEE Software, 1994, 11, 48-56. (68) Mamdani, E. H. IEEE Trans. Comput. 1977, 26, 1182-1191. (69) Pott, K. T.; Usifer, D.A.; Guadalupa, A.; Abruna, H. D. 4-Vinyl, 6-vinyl-, and 4′-vinyl2,2′:6′,2″-terpyridinyl ligand: their synthesis and the electrochemistry of their transitionmetal coordination complexs. J. Am. Chem. Soc. 1987, 109, 3961-3967.

26


Page 26 of 45

Page 27 of 45

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Tables for Main Text Table 1 Equilibrium constantsa,b (K / M-1) and detection limit for tpy-HPhImz-Anq towards Fand CN- and AcO- ions in MeCN and CN- in DMSO-H2O (4:6 v/v) solution at 298 K.

F-

In MeCN Solution From Absorption Spectra From Emission Spectra Equilibrium Detection Limit Equilibrium Detection constants constants Limit 2.63 ×105 M-1 7.94 × 10-7 3.58×105 M-1 5.75× 10-7 M.

CN-

1.27 ×105 M-1

AcO-

5.7 ×104 M-1

Anion

Anion

CN-

3.16×10-7

2.49 ×105 M-1

2.95 × 10-7 M

1.25 × 10-6M 6.26×104M-1 1.24 × 10-6 M In DMSO-H2O (4:6 v/v) solution From Absorption Spectra From Emission Spectra Equilibrium Detection Limit Equilibrium Detection constants constants Limit 1.97 x 103 M-1 1.16 × 10-5 M. 1.80 × 103 M 1.54 × 10-5 M.

t-Butyl salts of the respective anions were used for the studies. bEstimated errors were < 15 a

27



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

Page 28 of 45

Table 2 Selected MOs along with their energies and compositions in the ground state for tpy-HPhImz-Anq, tpy-PhImz-Anq, [Zn(tpyHPhImz-Anq)2]2+ , [Fe(tpy-HPhImz-Anq)2]2+ , and [Cu(tpy-HPhImz-Anq)2]2+ complex in MeCN.

tpy-HPhImz-Anq (%) Composition MO Energy/ Anthraquin tpy eV imd LUMO+3 -1.43 72.21 27.78 LUMO+2 -1.62 0.03 99.97 LUMO+1 -1.94 29.01 70.9 LUMO -2.89 94.48 5.50 HOMO -6.16 57.79 42.20 HOMO-1 -6.36 0.01 99.99 HOMO-2 -6.77 97.35 2.64 HOMO-3 -6.86 99.58 00.41 [Fe(tpy-HPhImz-Anq)2]2+ (%) Composition MO Energy/ Anthraquin tpy eV imd LUMO+3 -2.98 7.63 88.29 LUMO+2 -2.98 7.74 88.24 LUMO+1 -3.49 76.85 22.86 LUMO -3.62 86.51 13.27 HOMO -6.49 22.58 33.28 HOMO-1 -6.5 17.09 35.10 HOMO-2 -6.55 .03 22.00 HOMO-3 -6.82 42.99 22.19

tpy-PhImz-Anq (%) Composition Energy/ eV Anthraquin imd -1.0 91.41 -1.53 0 -1.62 9.77 -2.46 93.24 -5.29 72.94 -5.58 99.36 -6.23 99.22 -6.29 0

Fe 4.07 4.01 0.28 0.20 44.12 47.80 77.95 34.81

tpy 8.58 100 90.22 6.75 27.05 0.64 .73 100

[Cu(tpy-HPhImz-Anq)2]2+ (α MO) (%) Composition Energy/ Anthraquin tpy Cu eV imd -3.06 11.03 88.29 0.6 -3.06 8.67 90.59 0.7 -3.5 74.67 25.26 0 -3.63 85.22 14.74 0 -6.69 62.32 37.59 0 -6.72 52.31 47.60 0 -7.18 95.59 4.40 0 -7.18 94.29 5.70 0

28


Zn(tpy-HPhImz-Anq)2]2+ (%) Composition Energy/ Anthraquin tpy eV imd -2.98 9.68 89.68 -2.98 7.75 91.58 -3.49 76.43 23.54 -3.62 86.23 13.74 -6.66 61.62 38.36 -7.17 51.70 48.27 -7.18 95.59 4.40 -6.82 94.24 5.75

Zn 0.36 0.66 0 0 0 0 0 0

[Cu(tpy-HPhImz-Anq)2]2+ (β MO) (%) Composition Energy/ Anthraquin tpy Cu eV imd 8.64 90.57 tpy .8 75.17 24.55 8.64 .2 .24 32.45 75.17 67.29 85.63 14.33 .24 0 62.02 37.87 85.63 0 52.06 47.83 62.02 0 0 68.37 52.06 31.62 95.61 4.38 0 0

Page 29 of 45

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table 3 Selected UV-vis Energy Transitions at the TD-DFT/B3LYP Level of tpy-HPhImz-Anq, tpy-PhImz-Anq, [Zn(tpy-HPhImz-Anq)2]2+,[Cu(tpy-HPhImz-Anq)2]2+ and [Fe(tpy-HPhImzAnq)2]2+. Excited state

λ cal/nm /εcal/ M-1 cm-

Oscillator strength(f)

λ expt/nm /εexpt/ M-1 cm-1

tpy-HPhImz-Anq, S2 437(23265)

0.55

404(19108)

H→L(98%)

ILCT

S7

0.61

290(61728)

H→L+1(71%),H-5→L(11%),H-7→L(7%),H-4→L(7%)

π-π*, ILCT

1

326 (58394)

Key transitions

Character

tpy-PhImz-Anq S1

503 (26084)

0.60

480 (18596)

H→L(98%)

ILCT

S5

374 (24480)

0.52

342(28017)

H→L+1(97%)

ILCT

S15

305 (61802),

0.43

291(55871)

H-11→L(15%), H-1→L+3(34%),H→L+4(24%),H15→L(8%), H-12→L(3%), H-10→L(3%),H-6→L(3%)

π-π*, ILCT

[Zn(tpy-HPhImz-Anq)2]2+ S3

452(36070)

0.60

401(22536)

H→L+1 (97%)

ILCT

S11

373(36930)

0.82

327(37657)

H→L+3 (80%), H→L+2 (10%), H-1→L+2(8%)

ILCT

S59

293(66845)

0.86

284(47138)

H-1→L+7 (44%), H-1→L+8 (28%), H-6→L+4 (7%),H5→L+4 (6%)

ILCT

[Cu(tpy-HPhImz-Anq)2]2+ S19

452(45395)

0. 64

401(28443)

H(α)→L+1(α)(49%),H(β)→L+2(β) (48%)

ILCT

S42

379(40349)

0.88

335(36701)

ILCT

S161

301(68137)

0.67

290(54877)

H(α)→L+3(α)(39%), H(β) →L+4(β) (34%), H1(α)→L+2(α)(7%), H-1(β) →L+3(β) (6%), H(β) →L+3(β)(6%) H(α)→L+6(α)(45%), H(β)→L+7(β)(45%) H-1→L(71%), H-4→L(5%),H-1→L+2(3%),H1→L+3(3%),HOMO→L+1(8%),HOMO→L+2(4%) H-5→L(72%), H-4→L(19%)

MLTC

H-4→L+2(19%), H-4→L+3(14%), H-3→ L+2 (23%),H3→L+3(24%),H-1→L+2(4%), H-1 →L+3(5%)

ILCT

[Fe(tpy-HPhImz-Anq)2]

ILCT

2+

S4

486(44156)

1.14

575(21627)

S22

413(21955)

0.34

402(22872)

S32

359 (26444)

0.64

326(44764)

29


ILCT


Figures for Main Text

0.9

3 2 DMSO:Water(4:6) Solid

1 0

MeCN

300

400 500 λ/nm

600

(b)

1000 Counts(Log)

(a)

PL Int. (a.u.)

4

Abs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 30 of 45

0.6

DMSO:Water(4:6)

100

Pure MeCN Solid

10 1

10

τ/ns

20

30

DMSO:Water (4:6) Solid

0.3 0.0

Pure MeCN

500

600 λ/nm

700

Figure 1. Normalized UV-vis absorption and luminescence spectrum of tpy-HPhImz-Anq (a and b, respectively) in MeCN, DMSO: H2O (4:6 v/v) mixture and solid state. Inset of (b) shows the lifetime of the receptor.

30


Page 31 of 45

(a) Free

(c) F-

Cl-

Br-

I-

CN- H2PO4- AcO- NO3- ClO4-

(b )

800 -

Free,H2PO4 ,Cl

0.6

- -

-

500

λ/nm

I-

CN- H2PO4- AcO- NO3- ClO4-

(d) -

- -

-

-

F

0.2

400

Br-

Free,H2PO4 ,Cl

-

CN

300

Cl-

-

Br ,I ,NO3 ,ClO4

AcO

F-

-

0.4

0.0

Free

PL Int. (a.u.)

0.8

Abs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


-

-

Br ,I ,NO3 ,ClO4

600

CN

-

-

400

AcO F

200 0

600

-

500

600

λ/nm

700

Figure 2. Visual color changes of tpy-HPhImz-Anq in presence of different anions in MeCN under normal (a) and UV (c) light, while (b) and (d) represent the UV-vis absorption and emission spectral changes of tpy-HPhImz-Anq upon addition of different anions as their TBA salts.

31



0.18

800

Abs 479

0.2 0.0

5 -1 K=(2.63±24)x10 M -5

0.0

-5

2.0x10 4.0x10 [F ]/[mol/L]

600

300

1000

400 500 λ/nm Eq. F Free 0.5 1 2 3

-

τ1 (ns)

.25 .81 1.55 1.71 1.72

2.33 3.85 6.36 6.85 6.92

500

600

2.0x10

-5

4.0x10

700

λ/nm

(d)

Εq. F τ1 (ns)

Free

1000

1

2 3

.53 1.10 1.23 1.24

τ2 (ns)

3.21 3.85 4.61 4.65

100 10 1

50

-5

-

[F ]/[mol/L]

τ2 (ns)

10

20 30 40 Time(ns)

0.0

200

600

100

10

5 -1 K=(3.58±13) x 10 M

400

0

(c)

1

PL Int.(a.u.)

Abs

0.06 0.00

600

300

0.12

0.4

900

(b)

PL Int606nm

(a)

Counts(Log)

0.6

Counts(Log)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 32 of 45

10

τ/ns

20

30

Figure 3. Changes in UV-vis absorption (a) and emission (b) spectra and excited state decay profiles monitored at 528 nm (c) and at 607 nm (d) of tpy-HPhImz-Anq in MeCN upon incremental addition of F- ion. The insets to (a) and (b) show the fit of the experimental absorbance and luminescence data to a 1:1 binding profile, while inset to (c) and (d) shows the lifetimes.

32


Page 33 of 45

300

(a)

0.25

300

(b)

PL Int.(a.u.)554nm

0.9

0.10 0.05 0.000

0.3 0.0

-1

0.004 0.008 [CN-]/[mol/L]

0.012

CN -

300

Eq CN τ1(ns)

(c)

0 10 20 50 100 200

1000

4.05 1.44 1.60 1.73 2.73 2.92

0

τ2(ns)

-2

CN-

600 λ/nm

800 Eq CN τ1(ns)

(d)

0 10 50 100 200

1000

τ2(ns)

1.68 5.01 1.41 5.00 1.13 4.69 0.82 4.09 0.67 3.89

100

100 10 1

1.0x10 5.0x10 [CN ]/[mol/L]

100

600

4.29 4.83 6.53 7.03 8.26

-3

0.0

Free

400 500 λ/nm

-1

100

200

Counts(Log)

Free

3

K=(1.97±0.081) X 10 M

PL Int (a.u.)

Abs 482 nm

Abs

0.15

0.6

3

K=(1.80±0.09)x10 M

200

0.20

Counts(Log)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


10

20

30 τ/ns

40

10 1

50

10

20

30

τ/ns

40

50

Figure 4. Changes in UV-vis absorption (a) and emission (b) spectra and excited-state decay profiles (c: monitored at 556 nm, d: monitored at 618 nm) of tpy-HPhImz-Anq in DMSO: H2O (4:6 v/v) medium upon incremental addition of CN- ion. The insets to (a) and (b) show the fit of the experimental absorbance and luminescence data to a 1:1 binding profile and visual color change under normal and UV light, respectively while inset to (c) and (d) shows the lifetimes.

33



Free

CN-

I-

Br-

Cl-

F-

AcO-

H2PO4-

(a)

0.09

200

(b) -

- -

Free,Cl ,Br ,I ,AcO NO3 ,H2PO4 ,ClO4

F

-

CN

-

0.03

300

400

-

500 λ/nm

- -

-

Free,Cl ,Br ,I ,AcO NO3 ,H2PO4 ,ClO4

150 PL Int.(a.u)

0.06

0.00

(c)

-

Abs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 34 of 45

100 F

CN

50 0

600

-

600 λ/nm

-

800

Figure 5. (a) Visual color change that occur upon mechanical grinding the receptor with TBA salt of different anions and their UV-vis absorption (b) and emission (c) spectra.

34


Page 35 of 45

0.6

800

(a)

(b)

Cd

2+

Al

0.4

C u 2+

Z n 2+

PL Int.(a.u.)

F e 2+

F ree 2+

Ni

Free

Abs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


0.2

2+

Zn Cu2+ 3+ Al Co

2+

Fe

2+

2+

Cd

3+

Zn

600

2+

Free

400 Ni

200

2+

Co

2+

Fe

2+

Cu

0.0

300

400 500 λ/nm

600

0

700

500

600 λ/nm

2+

700

Figure 6. Changes in UV-vis absorption (a) and emission (b) spectral profiles of tpy-HPhImzAnq in MeCN when treated with various metal cations as their perchlorate salts. Inset to (a) shows the visual color change upon addition of selected cations.

35



400

0.25

(a)

0.20

0.10

0.6 Abs

0.05 0.00 0.0

0.2 0.4 2+ 0.6 Equiv.Fe

0.8

0.3

0.0 200

400

λ/nm

PL Int.(a.u.)

Abs 557nm

0.15

300

300 200 100 0.0

200

0

500

600

λ/nm

600

516nm

500

0.2

400

0.1 0.0

0.3

0.0 200

550

PL Int.(a.u.)

Abs 339nm

0.6

700

600

(d)

0.3

PL Int.(a.u.)

(c)

0.3 0.6 2+ Equiv. Fe

100

600

0.9

400

(b) PL Int.(a.u.) 528nm

0.9

Abs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 36 of 45

400 λ/nm

0.2 0.4 0.6 2+ Equiv. Zn

0.8

450 400 350

0.0

0.2 0.4 0.6 Equiv. Zn2+

0.8

200

0

600

500

600 λ/nm

700

Figure 7. UV-vis absorption and emission spectral changes of tpy-HPhImz-Anq in MeCN upon incremental addition of Fe(ClO4)2 (a and b) and Zn (ClO4)2 (c and d). The insets show the change of absorption and emission intensity as a function of the equivalent of Fe2+ and Zn2+ ion added.

36


Page 37 of 45

6.0x10

(a)

2.0x10

4

4.0x10

4

2.0x10

4

-1

4

(c) Exp Theory

ε mol cm

4.0x10

4

Exp Theory

4

-1

ε m-1 cm-1

6.0x10

(b)

4.0x10

4

2.0x10

4

ε mol-1 cm-1

4

-1

6.0x10

8.0x10

4

6.0x10

4

4.0x10

4

2.0x10

4

6.0x10

4

4.0x10

4

2.0x10

4

0.0 400

500 λ /nm

600

(e)

700

Theory Exp

-1

ε mol cm

-1

300

Experimental Theory

(d)

Exp Theory

-1

ε m cm

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


0.0 300

400

500

λ /nm

600

700

Figure 8. Experimental and calculated absorption spectra of tpy-HPhImz-Anq (a), tpy-PhImzAnq (b), [Fe(tpy-HPhImz-Anq)2]2+ (c), [Cu(tpy-HPhImz-Anq)2]2 (d) and [Zn(tpy-HPhImzAnq)2]2+ (e) respectively in MeCN. 37



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

Page 38 of 45

HOMO

LUMO

(a)

LUMO+1

(b) (c)

LUMO+2(β)

LUMO

LUMO

(d)

(e)

LUMO+1(α)

HOMO

HOMO-1

LUMO

HOMO(β)

HOMO HOMO-1

HOMO(α)

HOMO-4

Figure 9. Energy level diagram depicting the dominant transition that comprises the lowest-energy absorption band for tpy-HPhImzAnq (a), tpy-PhImz-Anq (b), [Fe(tpy-HPhImz-Anq)2]2+(c),[Zn(tpy-HPhImz-Anq)2]2+(d) and [Cu (tpy-HPhImz-Anq)2]2+(e) respectively in MeCN. 38


Page 39 of 45

(a) F-

Z n 2+

Abs 340nm

F re e

F - + Z n 2+

0.2

0.4

0

300

1 0

400 500 λ/nm

Abs 477nm

1 0

0.1

600

0

(e)

L+F-

L

0.2

0.2 0.0

(b)

0.4

0.6

Abs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(c)

L+F-

L

In2 Zn2+

In1 F-

(d)

L+Zn+2 L+F-+Zn+2

0 1 0 1

0 0 1 1

L+Zn+2

Output1 Abs at 340nm 0(Low) 1(High) 1(High) 0(Low)

L+F-+Zn+2

Output2 Abs at 477nm 0(Low) 1(High) 0(Low) 0(Low)

Figure 10. XOR and INHIBIT logic gate based on tpy-HPhImz-Anq by monitoring the absorption spectral change at 340 nm and 477 nm in presence of F- (3 equiv) and Zn2+ (0.5 equiv) (a), horizontal and vertical dotted line represent the threshold value and corresponding wave length (inset shows the colour change in presence of different inputs). (b) and (c) represent the histogram at 340 nm and 477 nm. (d) Schematic representation of half-subtractor logic circuit by combination of XOR and INHIBIT logic gates. (e) Corresponding Truth Table of the combined logic circuit.

39



(a)

(b)

Free+Cu2++Fe+2(5) Free+Cu2+(3)

0.6

Free+Fe+2+Cu2+(4)

Abs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 40 of 45

Free(1) Free+Fe2+(2)

0.3

(c)

0.0

300

400

500

600

(d) 2

3

4

In2 Cu2+

0 1 0 1(1st ) 1(2nd)

0 0 1 1(2nd) 1(1st)

700

λ/nm

1

In1 Fe2+

5

Output Abs 576nm 0(low) 1(high) 0(low) 1(high) 0(low)

Figure 11. (a) UV-vis absorption spectral changes of tpy-HPhImz-Anq in presence of Fe2+ (0.5 equiv) and Cu2+ (0.5 equiv). (b) Schematic representation of keypad to access a secret code by monitoring absorbance at 576 nm with different input sequences; (c) Truth table of molecular keypad lock. (d) Sequence dependent color change of the receptor.

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IMP

INH

Figure 12. INHIBIT and IMPLICATION logic gate based on tpy-HPhImz-Anq by monitoring the emission spectral change at 607nm and 528 nm in presence of F- (3 equiv) and Zn2+ (0.5 equiv) ions (a), horizontal and vertical dotted line represent the threshold value and corresponding wave length. (b) and (c) represent the histogram at 607and 528 nm . (d) A schematic representation of a complementary output IMP/INH circuit. (e) Corresponding Truth Table of the combined logic circuit.

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(a)

(c)

Memory element

In2 Reset

Output1 Emission at 607nm

In1 Set (b)

Set In1

In1 FSet 0 1 0 1

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In2 Zn2+ Reset 0 0 1 1

Output1 Emission at 607nm 0(Low) 1(High) 0(High) 0(Low)

Writing Emission at 607nm ON

Emission at 607nm OFF

Erasing Reset In2

Figure 13. (a) Sequential logic circuit displaying memory unit with two inputs (In 1 and In 2) and one output; (b) Schematic representation of the reversible logic operation for the memory element with “writing-reading-erasing-reading” kind of behavior, (c) Corresponding Truth Table.

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Figure 14. Schematic presentation of fuzzy relation based on fuzzy inference rules taking Cu2+ as input and the emission quantum yield (ΦF) as the output. The change of emission intensity of tpy-HPhImz-Anq as a function of Cu2+ is represented in the green box. Fuzzy variables are decomposed in three fuzzy sets. Cu2+: (1) low (zmf µlow, [0.02 0.18]); (2) medium (trimf µmedium, [0.05 0.25 0.45]); (3) high (smf µhigh, [0.32 0.48]). ΦF: (1) low (zmf µlow, [0.0512 0.1408]); (2) medium (trimf µmedium, [0.068 0.18 0.292]); (3) high (smf µhigh, [0.2192 0.3088]).

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Figure 15. Three-dimensional representation of the dependence of emission quantum yield (ΦF) of tpy-HPhImz-Anq as a function of simultaneous injection of two chemical inputs (Fe2+ and F-).

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Table of Content Anthraimidazoledione-Terpyridine Based Optical Chemosensor for Anions and Cations That Works as Molecular Half-Subtractor, Key-Pad Lock and Memory Device Debiprasad Mondal, Manoranjan Bar, Dinesh Maity, and Sujoy Baitalik*

Anthraquinone and imidazole functionalized terpyridine conjugate as molecular half-subtractor, key-pad lock and memory device

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Anthraimidazoledione-Terpyridine-Based Optical ... - ACS Publications

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