Dicyanovinyl Moiety Research Articles

Ratiometric detection and monitoring of cyanide in biological, environmental and food samples by a novel triphenylamine-xhantane based fluorescent probe

BackgroundAs cyanide (CN−) is a significant hazard to the environment and human health, it is essential to monitor cyanide levels in water and food samples. Moreover, real-time visualization of CN−could provide an additional understanding of its critical physiological and toxicological roles in living cells. The fluorescence approach based on small organic probes is an effective way for the detection of CN−. In this approach, a triphenylamine-xhantane conjugate was applied to detect in many samples such as sewage water, soil, sprouted potato, apricot seed, and living cells. ResultsWe report a new ratiometric near-infrared fluorescent probe based on a triphenylamine-xhantane derivative for CN−sensing in many samples. The probe displays high selectivity for only CN− ions among a series of analytes. The addition of cyanide to the dicyanovinyl moiety of the probe disrupts π-conjugation followed by the interruption of internal charge transfer. Consequently, the emission peak of the probe shifts hypsochromically from 655 to 495 nm. There is a linear correlation between the emission intensity (I495) and cyanide level, with a detection limit of 0.036 μM. The probe has many advantages over many probes, such as NIR fluorescence, ratiometric response, low cytotoxicity (85.0 % cell viability up to 50.0 μM of the probe), good membrane permeability, fast response time (4.0 min), high selectivity, good photostability, and anti-interference capability. SignificanceAlthough various probes have been reported in the literature, the use of triphenylamine-xhantane unit as CN− probe has yet to be explored. The probe can detect trace levels of cyanide in many samples such as sewage water, soil, sprouted potatoes, and apricot seeds. Furthermore, it is successfully utilized for the ratiometric fluorescent bioimaging of cyanide in living cells.

Swift and quantitative naked-eye detection of cyanide: A dual-mode approach using an ICT-based colorimetric and ratiometric fluorescent chemodosimeter

A chemodosimeter (1) based on dicyanovinyl with a strong intramolecular charge transfer (ICT) mechanism has been devised for the selective and sensitive detection of cyanide (CN−) in a tetrahydrofuran aqueous solution. In polar solvents, chemodosimeter 1 exhibits robust ICT-induced emission; however, in the solid state, its fluorescence weakens owing to the formation of molecular aggregates prompted by intermolecular π–π interactions. The colorimetric and ratiometric fluorescent changes observed in the chemodosimeter upon exposure to CN− result from the incorporation of CN− at the β-conjugated site of the dicyanovinyl moiety of chemodosimeter 1, effectively hindering the ICT process. This alteration is supported by 1H NMR titration experiments and density functional theory calculations, which corroborate the cyanide-induced ICT on–off switching mechanism. The detection limit of chemodosimeter 1 (5.8 × 10−7 M) for CN− falls below the maximum allowable level of cyanide in drinking water (1.9 × 10−6 M), as established by the World Health Organization. Test strips utilizing chemodosimeter 1 offer a potential solution for swift and quantitative naked-eye detection of CN− in real-time scenarios. Moreover, chemodosimeter 1 was effectively employed for detecting cyanide in actual environmental water samples.

Highly Efficient β‐Functionalized Oxidomolybdenum(V) Corroles for Catalytic Oxidative Bromination of Phenols at Room Temperature

AbstractTwo new β‐functionalized oxidomolybdenum(V) corroles, oxido[3‐formyl‐5,10,15‐triphenylcorrolato]molybdenum(V) (Mo‐1) and oxido[3‐dicyanovinyl‐5,10,15‐triphenylcorrolato]molybdenum(V) (Mo‐2) were synthesized and characterized by various spectroscopic techniques and electrochemical studies. Mo‐2 manifests splitted B bands due to x and y polarizations and highly red shifted longest B and Q bands due to the electron‐deficient nature of the dicyanovinyl group. EPR data showed that these complexes exhibit an axial compression with dxy1 configuration. DFT studies revealed that HOMO and LUMO orbitals are stabilized in Mo‐2 relative to Mo‐1. Mo‐1 exhibits two successive reversible reductions and two oxidation potentials in cyclic voltammetry. Surprisingly, Mo‐2 exhibits three successive reversible reductions and two oxidations; the one extra reduction could possibly be due to the reduction of the dicyanovinyl moiety. The catalytic activities of Mo‐1 and Mo‐2 for the oxidative bromination of various phenols using H2O2‐KBr‐HClO4 mixture in water have been explored and exhibited excellent activity at a very low catalyst loading of 0.0030 and 0.0028 mol%, respectively. Both synthesized β‐functionalized Mo(V) corroles manifest much higher conversion and TOF (59801–71174 h−1) for oxidative bromination of phenols relative to earlier reported meso‐functionalized Mo(V) corroles (20781–61646 h−1). Hence, Mo‐1 and Mo‐2 mimic vanadium bromoperoxidase (VBPO) and act as functional models for these catalytic applications. These catalysts were reused upto 3 cycles and showed conversion rate upto 82 % indicating their excellent thermal and chemical stabilities.

Highly twisted luminogen based on asymmetric D-A-D’ type dicyanovinyl derivative decorated dibenzofuran and carbazole with aggregation-induced emission enhancement and obvious mechanochromic behavior

A novel asymmetric D-A-D’ type dicyanovinyl derivative DBF-DCN-Cz, which was constructed with a dibenzofuran unit and a carbazole moiety bridged by a dicyanovinyl spacer, was designed and synthesized. It was found that the luminogen DBF-DCN-Cz showed unique intramolecular charge transfer (ICT) process from electron-donating carbazole unit to electron-accepting dicyanovinyl moiety. Optical studies and theoretical calculations indicated that DBF-DCN-Cz possessed highly twisted conformation and aggregation-induced emission enhancement (AIEE) property because of the presence of the large steric hindrance. Interestingly, the emitting color of solid powder of DBF-DCN-Cz changed from initial bright yellow to orange after grinding, showing obvious mechanochromic luminescence (MCL). XRD and DSC experiments confirmed that the MCL phenomenon originated from the phase transition from crystalline to amorphous states. This work might broaden the knowledge for AIE-active MCL materials and laid the foundation for their extensive applications.

Dual-functional turn-on fluorescent probe for discriminative sulfite and sulfide detection via organic/aqueous ratio tuning and its application in real samples

Sulfite and sulfide are substances commonly present in food, biological and industrial processes. While excess amounts of these anions can elicit physiological disorders in humans, there are only limited examples of probes capable of selectively detecting both of them. In this study, we present a sulfite/sulfide dual-functional probe 1 based on a dimethylaminonaphthalene-oxazaborine fluorophore and a dicyanovinyl reaction site. Probe 1 enabled a highly selective detection of sulfite under acetonitrile/tris buffer (85:15, v/v), discriminating sulfite from common interfering species such as sulfide, cyanide, and biothiols. The probe fully responded to sulfite within 4 min, with an 18-fold increase in the fluorescence intensity. Besides, probe 1 was also able to selectively sense sulfide in pure acetonitrile, while displaying a detection limit as low as 96 nM. Mechanistic studies revealed that a large 170 nm Stokes shift of the probe after sulfite/sulfide detection can be ascribed to the nucleophilic addition of sulfite/sulfide to the dicyanovinyl moiety, which broke the conjugation system between the fluorophore scaffold and the dicyanovinyl group, thereby triggering the intramolecular charge transfer effect. Finally, the probe displayed good capability for sensing sulfite and sulfide in real samples with good recoveries, proving its potential in the determination of sulfite and sulfide concentrations for real-life applications.

A NIR fluorescent sensor based on thiazoline-isophorone with low cytotoxicity in living cells for Hg2+ detection through ICT associated hydrogen bonding effect

Mercury (Hg) is a toxic pollutant and may cause serious health and environmental threats even at low concentrations. Thus, sensitive, efficient, and accurate techniques for the detection of Hg2+ ions in biological systems are in particular demand. In the current paper, a new, red emitting fluorescence probe (THI) based on electron deficient dicyanovinyl, electron-rich diethylamino, and receptor thiazoline toward Hg2+ has been developed. It has been determined that the recognition behavior of the probe toward Hg2+ is reversible with S2−. The probe not only shows perfect selectivity toward Hg2+ with a low detection limit over a series of metal ions, but it also displays positive solvato-chromism among the tested solvents via modulation of intramolecular energy transfer from the diethylamino to a dicyanovinyl moiety. Furthermore, it has been shown that the probe can be applied as a fluorescent probe for visualizing Hg2+ in living HeLa cells through a confocal laser scanning microscope. Also, the probe THI has not shown any toxic effect in cervical cancer and epithelial cells. Thus, the probe demonstrates high promise for Hg2+ detection in biomarker screening, disease diagnosis, and clinical medicine with low cytotoxicity.

Novel styrylbenzimidazolium-based fluorescent probe for reactive sulfur species: Selectively distinguishing between bisulfite and thiol amino acids

In this study, a new fluorescent probe containing dicyanovinyl moiety has been designed and synthesized. Fluorescent probe based on styrylbenzimidazolium derivative was reported for the effective detection of bisulfite and distinguish it from biothiols by exploiting dicyanovinyl group as the recognition site. The photophysical properties of the novel styrylbenzimidazolium derivative were assessed by determination of absorption and fluorescence spectra, fluorescence quantum yield, and fluorescence lifetime. Its spectroscopic behavior towards various analytes has been evaluated in aqueous media at a pH of 7.4. The highest increase in fluorescence intensity of compound 5 in the presence of different analytes was observed for sodium bisulfite and the limit of detection was estimated to be 0.25 μM. The styrylbenzimidazolium dye was applied to detect bisulfite in various wine sample using fluorimetry. Finally, the ability of this novel probe to detect HSO3− in red wine samples was evaluated.

Phenanthroimidazole and dicyanovinyl-substituted triphenylamine for the selective detection of CN−: DFT calculations and practically applications

A novel CN− selective fluorescent turn-on sensor (TPMN) possessing triphenylamine and phenanthroimidazole as signaling units and dicyanovinyl unit for the binding site was designed and synthesized. TPMN exhibited a drastic change in its emission spectra with about 13-fold fluorescence enhancement when treated with CN−, while other tested anions could not arouse the fluorescence enhancement. The experimental and theoretical calculation results showed that this increase in fluorescence intensity of TPMN in presence of CN− is due to the large decrease in the ICT effect by the addition of CN− ion to β-carbon of the dicyanovinyl moiety. TPMN could selectively detect CN− with a detection limit of 0.23 μM among the common anions. The CN−-binding mode was well-characterized to be 1:1 by using Job’s plot with an association constant of 5.36 (logKa). Besides, the possible utilization ofTPMN was successively tested in water samples and test kits.

Hydrazine-Selective Fluorescent Turn-On Probe Based on Ortho-Methoxy-Methyl-Ether (o-MOM) Assisted Retro-aza-Henry Type Reaction.

Hydrazine (N2H4) is one of the most widely used industrial chemicals that can be utilized as a precursor of pesticides, pharmaceutics, and rocket propellant. Due to its biological and environmental toxicity with potential health risks, various sensing tools have been developed. Among them, fluorescence-based molecular sensing systems have been highlighted due to its simple-operation, high selectivity and sensitivity, and biocompatibility. In our recent report, we disclosed a ratiometric type fluorescent probe, called HyP-1, for the detection of hydrazine, which is based on ortho-methoxy-methyl-ether (o-MOM) moiety assisted hydrazone-formation of the donor (D)-acceptor (A) type naphthaldehyde backbone. As our follow-up research, we disclose a turn-on type fluorescent probe, named HyP-2, as the next-generation hydrazine probe. The sensing rational of HyP-2 is based on the o-MOM assisted retro-aza-Henry type reaction. The dicyanovinyl moiety, commonly known as a molecular rotor, causes significant emission quenching of a fluorescent platform in aqueous media, and its cleavage with hydrazone-formation, which induces a significant fluorescence enhancement. The high selectivity and sensitivity of HyP-2 shows practical explicabilities, including real-time paper strip assay, vapor test, soil analysis, and real water assay. We believe its successful demonstrations suggest further applications into a wide variety of fields.

Isophorone‐boronate ester: A simple chemosensor for optical detection of fluoride anion

A highly selective isophorone‐boronate ester based chemosensor, (1), having a dicyanovinyl moiety as a convenient colorimetric probe, has been designed. Different types of anionic analyte such as CH3COO−, ClO4−, Cl−, F−, PF6−, Br− and HSO4− were tested and among them only highly nucleophilic F− anion displayed significant response towards the sensor. Addition of the fluoride anion across the boron atom disrupts the π‐conjugation thereby shifts the absorption wavelength towards the redshift region due to the decrease in the HOMO‐LUMO energy gap and a colour change from yellow to blue is observed under visible light condition. The detection limit of this probe was calculated to be 3.25 × 10—8 M for fluoride anion. The binding constants and the detection limits of the sensor were calculated using absorption titration studies. The silica gel TLC strips dip‐coated by the chemosensor (1) revealed a colour change from yellow to brick red to naked eye.

Synthesis of Novel Intramolecular Charge-Transfer Molecules Bearing Triphenylamine and Benzothiadiazole Moieties, and Application to Single-Absorber Organic Solar Cells

Organic solar cells (OSCs) have been extensively studied due to their potential for flexible, printable, and low-cost devices. Recently, power conversion efficiency (PCE) has reached around 10% by using bulkhetero junction (BHJ) system which possesses miscible interface between two kinds of materials, electron donor and acceptor. In the BHJ system, LUMO offset is required to promote charge separation at donor-acceptor interface, causing serious photovoltage loss. In order to overcome this problem, we have pursued the possibility of single-absorber organic solar cells, whose active organic layer consists of one component. Generally, photogeneration efficiency in organic bulk film is quite low because of the large exciton binding energy (EBE). In previous work, we found that molecules with intramolecular charge transfer photoabsorption are suitable for the single-absorber OSC. A donor-acceptor (D-A) linked molecule DTDCPB (Fig. 1) was applied to the single absorber OSC, and comparatively good performance was obtained. In this study, we synthesized novel donor-acceptor linked molecules bearing triphenylamine and benzothiadiazole moieties by derivatizing DTDCPB (Fig. 1). DTDCPB was extended by insertion of thienothiophene at the donor-acceptor linkage part to form DTDCPB-TT. DTERPB and DTRCNPB bear an acceptor moiety of 3-ethyl rhodanine and 2-(3-ethyl-4-oxothiazolidin-2-ylidene)malononitrile, respectively, instead of dicyanovinyl moiety. EBEs in the solid state were estimated with quantum chemical calculation to design a suitable molecule for lower EBE. The D-A molecules were applied to a single absorber OSC composed of ITO/PEDOT:PSS/organic/Ca/Al. In the DTDCPB-TT device, FF and hole mobility increased compared with those in the DTDCPB device because the film crystallinity was improved due to thienothiophene. In the DTERPB and DTRCNPB devices, the photovoltage loss was only 0.60 V, that was less than that of the typical BHJ system. The ratio of the voltage loss to the absorbed energy was 33% for DTERPB and 35% for DTRCNPB, which were rather small in comparison with the typical BHJ system, e.g. 65% for P3HT:PC61BM and 56% for PTB7:PC71BM. Figure 1

A convenient colorimetric and ratiometric fluorescent probe for detection of cyanide based on BODIPY derivative in aqueous media

A convenient colorimetric and ratiometric fluorescent probe based on BODIPY derivative for cyanide detection has been synthesized, whose structural contains a dicyanovinyl group used as a sensing unit. Among the tested analytes, such as CN−, F−, Cl−, Br−, I−, ClO4−, AcO−, NO3−, H2PO4− HSO4−, S2− and N3−, only CN− could react with dicyanovinyl moiety by nucleophilic addition, which disrupted the π-conjugation of the probe and hindered the intramolecular charge transfer (ICT), leading a blue shift of absorption and fluorescence spectrum and a concomitant color change from yellow to light pink. The detection limit of this probe was calculated to be 0.98 μM, which is lower than the maximum concentration in drinking water (1.9 μM) permitted by the World Health Organization (WHO). Moreover, the probe showed excellent selectivity and anti-interference ability towards CN− over other anions. The reaction mechanism was fully supported by 1H NMR and MS spectrum.

DFT Study of the Structure, Reactivity, Natural Bond Orbital and Hyperpolarizability of Thiazole Azo Dyes.

The structure, reactivity, natural bond orbital (NBO), linear and nonlinear optical (NLO) properties of three thiazole azo dyes (A, B and C) were monitored by applying B3LYP, CAM-B3LYP and ωB97XD functionals with 6-311++G** and aug-cc-pvdz basis sets. The geometrical parameters, dipole moments, HOMO-LUMO (highest occupied molecular orbital, lowest unoccupied molecular orbital) energy gaps, absorption wavelengths and total hyperpolarizabilities were investigated in carbon tetrachloride (CCl4) chloroform (CHCl3), dichloromethane (CH2Cl2) and dimethlysulphoxide (DMSO). The donor methoxyphenyl group deviates from planarity with the thiazole azo moiety by ca. 38°; while the acceptor dicyanovinyl, indandione and dicyanovinylindanone groups diverge by ca. 6°. The HOMOs for the three dyes are identical. They spread over the methoxyphenyl donor moiety, the thiazole and benzene rings as π-bonding orbitals. The LUMOs are shaped up by the nature of the acceptor moieties. The LUMOs of the A, B and C dyes extend over the indandione, malononitrile and dicyanovinylindanone acceptor moieties, respectively, as π-antibonding orbitals. The HOMO-LUMO splittings showed that Dye C is much more reactive than dyes A and B. Compared to dyes A and B, Dye C yielded a longer maximum absorption wavelength because of the stabilization of its LUMOs relative to those of the other two. The three dyes show solvatochromism accompanied by significant increases in hyperpolarizability. The enhancement of the total hyperpolarizability of C compared to those of A and B is due to the cumulative action of the long π-conjugation of the indanone ring and the stronger electron-withdrawing ability of the dicyanovinyl moiety that form the dicyanovinylindanone acceptor group. These findings are facilitated by a natural bond orbital (NBO) technique. The very high total hyperpolarizabilities of the three dyes define their potent nonlinear optical (NLO) behaviour.

An AIE and ICT based NIR florescent probe for cysteine and homocysteine

A combination of aggregation-induced emission and intramolecular charge transfer was achieved by using a triphenylamine analogue and a dicyanovinyl moiety as the electron donating and accepting units, respectively. Hence, we designed and synthesized a probe with a D-π-A framework as a near-infrared fluorescence turn-on probe for biothiols (cysteine and homocysteine). Owing to the remarkable intramolecular charge transfer effect as well as intramolecular rotations associated with the donor moiety, the probe exhibits extremely weak fluorescence, which becomes a good starting point for developing fluorescence “turn-on” probes. Upon reaction with cysteine or homocysteine utilizing the dicyanovinyl moiety, the intramolecular charge transfer character was weakened, and the reacting products were observed to aggregate in aqueous solutions, resulting in the aggregation-induced emission effect with red fluorescence at 651 and 656 nm, respectively. Hence, the probe could be used as a fluorescence “turn-on” sensor for cysteine and homocysteine, with the sensing time of less than 4 min and the detection limits of 8.4 μM and 5.7 μM towards cysteine and homocysteine, respectively. The probe could distinguish cysteine and homocysteine from glutathione. The sensing mechanism was systematically investigated by employing high resolution mass spectrometry, 1H NMR and density functional theory calculations as well as checking the solvent viscosity dependent fluorescence, and thus the nucleophilic addition products, the intramolecular charge transfer character, and the aggregation-induced emission behaviour were clearly elucidated. It is noteworthy that the low cytotoxicity, the intrinsic aggregation-induced emission nature and near-infrared emissions enable the application of the probe in living cell imaging.

A novel colorimetric and fluorescent sensor for cyanide anions detection based on triphenylamine and benzothiadiazole

A chemical sensor containing triphenylamine and benzothiadiazole for cyanide anions detection was designed and synthesized, whose structural feature is a donor-acceptor-donor (D-A-D) molecular configuration, which is substituted with a dicyanovinyl group served as a sensing unit. The nucleophilic addition of cyanide ion to the dicyanovinyl moiety was activated in the principle of Michael addition, which broken the electron-withdrawing interaction of dicyanovinyl moiety. The obstruction in the intramolecular charge transfer (ICT) induced remarkable changes in the absorption and emission spectra. The sensor exhibited splendid selectivity and anti-interference performance towards CN− over other anions (F−, Cl−, Br−, I−, NO2−, NO3−, HCO3−, H2PO4−, HS−, HSO3−, NCO−, SCN−, SO32−, SO42−, HPO42−, CO32−). The mechanism was investigated by absorption and emission spectra together with 1H NMR titration.

Switching between porphyrin, porphodimethene and porphyrinogen using cyanide and fluoride ions mimicking volatile molecular memory and the 'NOR' logic gate.

β-Functionalization of meso-tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin with electron acceptors such as formyl and dicyanovinyl has been reported for the first time. 2-Formyl-5,10,15,20-tetrakis(3',5'-di-tert-butyl-4'-hydroxyphenyl)porphyrinatocopper(ii) (Cu-TDtBHPP-CHO) crystallizes in the triclinic space group P1[combining macron], [a = 10.8479(4) Å, b = 14.6207(5) Å, c = 15.9745(5) Å, V = 2198.97(13) Å3] and exhibits an almost planar structure and a square planar geometry. β-Formyl/dicyanovinyl substituted porphyrins such as Cu-TDtBHPP-CHO, Ni-TDtBHPP-CHO, Cu-TDtBHPP-MN (1), Ni-TDtBHPP-MN (2) and H2-TDtBHPP-MN (3) exhibited red-shifted optical absorption features (Δλmax = 13-40 nm) in CH2Cl2 compared to the corresponding MTPPs. β-Dicyanovinyl substituted porphyrins were developed as a quantitatively operating 'lab-on-a-molecule' for the visual detection of F- and CN- ions. Having a CN- ion responsive dicyanovinyl moiety and a F- ion responsive redox-active 3,5-di-tert-butyl-4-hydroxyphenyl groups, they detect F- and CN- ions simultaneously by switching unique structural changes between porphyrin, porphodimethene and porphyrinogen along with distinct colour changes which were monitored by UV-Vis-NIR, fluorescence and NMR spectroscopic techniques.

A simple 7-azaindole-based ratiometric fluorescent sensor for detection of cyanide in aqueous media

A simple, relatively low molecular weight 7-azaindole derivative was synthesized and fully characterized. The 1-methyl-7-azaindole moiety was substituted with a dicyanovinyl group which served as an electron-withdrawing group and also as a sensing unit. The nucleophilic addition of cyanide ion to the dicyanovinyl moiety induces a remarkable change in the emission spectrum, enabling ratiometric fluorescent sensing of cyanide ions in aqueous media. An excited state intramolecular charge transfer mechanism played a key role in the sensing event and the mechanism was supported by density functional theory and time-dependent density functional theory calculations. Furthermore, test strips containing the sensor molecule were easily fabricated and provide a low-cost, practical and efficient test kit for cyanide ion.

Synthesis of alkylphenanthrenes from naphthylalkylidenemalonodinitriles. A route to 1-methyl-, 2-methyl-, and 1,2-dimethylphenanthrene

The study has been carried out to evaluate the feasibility of synthesis of 1-methyl-, 2-methyl-, 1,2-dimethyl-, and 1-ethyl-2-methylphenanthrene through the annulation of the naphthalene system with the exploitation of the dicyanovinyl moiety of 2-naphthylalkylidenemalonodinitriles as an active electrophile in cold solutions of concentrated sulfuric acid. 2-(2-Naphthyl)propanal ( 3 ), 1-(2-naphthyl)propan-2-one ( 9 ), 3-(2-naphthyl)butan-2-one ( 14 ), and 3-(2-naphthyl)pentan-2-one ( 19 ) had been condensed with malonodinitrile to afford 2-naphthylalkylidenemalonodinitriles which were then cyclised to give 4-amino-1-methylphenanthrene-3-carbonitrile ( 5 ), 4-amino-2-methylphenanthrene-3-carbonitrile ( 11 ), 4-amino-1,2-dimethylphenanthrene-3-carbonitrile ( 16 ), and 4-amino-1-ethyl-2-metylphenanthrene-3-carbonitrile ( 21 ). The nitrile function has been removed from the aminonitriles, with the exception of 21 , through hydrolysis and decarboxylation in alkaline ethanolic solutions under elevated pressure (∼3 MPa) and temperature 220–230°C to give the respective 4-amino-methylphenanthrenes. Diazotisation of the phenanthreneamines and the reaction with hypophosphorus acid has lead to the methylphenanthrenes in moderate yields (50–52%).

Synthesis, electrochemistry and ab initio molecular orbital calculations on some norbornane- and bicyclo[2.2.2]octane-fused 5,12-bis(dicyanomethylidene)naphthalene systems

A series of norbornane- and bicyclo[2.2.2]octane-fused tetracyanonaphthoquinodimethane (benzoTCNQ) derivatives, 4,6,8,10 and 12 has been synthesized. Cyclic voltammetry measurements revealed two one-electron reduction waves for the benzo-TCNQ systems 4, 8 and 10 which possess either a cyclobutane or a norbornane moiety fused to the quinonoid ring, but a single (presumably two-electron) reduction wave for 6 and 12 which possess a bicyclo[2.2.2]octane group fused to the gmnonoid ring. The benzo-TCNQ systems were found to be potent electron acceptors. The results of (U)HF/3-21G calculations carried out on representative benzo-TCNQ derivatives suggest that steric interactions between the quinonoid ring and its adjacent fused alicyclic group are largely responsible for the observed decrease in the electron affinities along the series: 8 > 4 > 6. The MO calculations further suggest that LUMO energies of neutral TCNQ derivatives are qualitatively reliable predictors of electron affinities. The calculated (gas phase) internal reorganization energies, λi, for the benzo-TCNQ systems are ca. 54 kJ mol–1 and are comparable to that calculated for the dicyanovinyl (DCV) system, 27. The similarity between the λi values for the benzo-TCNQ systems and 27, together with the experimental finding that benzo-TCNQ systems are reduced at ca. 1.7 V less negative potentials than 27, should make the norbornane- and bicyclo [2.2.2] octane-benzo-TCNQ systems superior to the DCV moiety as acceptor chromophores in giant multichromophoric systems.