Thin films of non-peripherally substituted liquid crystalline phthalocyanines A

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Three non-peripherally substituted liquid crystalline bisphthalocyanine (Pc) compounds have been studied to examine the role of central metal ions lutetium (Lu), and gadolinium (Gd) and substituent chain lengths, i.e. octyl (C8H17) and hexyl (C6H13), in determining the physical properties. For the octyl substituted Pc molecules, the head-to-tail or Jaggregates within the as-deposited spun films produced a redshift of the optical absorption Q bands in relation to their 0.01 mgml-1 solutions. Annealing at 80˚C produced a well-ordered discotic liquid crystalline (LC) mesophase causing additional redshifts irrespective of the metal ion in case of C8LuPc2 and C8GdPc2. Formation of face-to-face or H-aggregated monomers led to blueshifts of the Q bands with respect to solution spectra for C6GdPc2, both as-deposited and annealed films. Stretching and bending vibrations of pyrrole, isoindole, and metal-nitrogen bonds in Pc rings showed Raman bands at higher energy for smaller metal ion. However, no change was observed for the difference in chain lengths. As-deposited C8LuPc2 and C6GdPc2 produced comparable Ohmic conductivity, of the value 67.55 Scm-1 and 42.31 Scm-1, respectively. C8GdPc2 exhibited two orders of magnitude less conductivity than the other two due to the size effect of the central ion and side chain length. On annealing, an increase of Ohmic conductivity was noticed in the isostructural octyl substituted phthalocyanines on contrary to a reduced conductivity in hexyl substituted one. An optical band shift of the C8LuPc2 and C8GdPc2 thin films occurred on oxidation by bromine vapour. Oxidations of Pc-coated ITO were also achieved by applying potential at 0.88 V and 0.96 V electrochemically for the C8LuPc2 and C8GdPc2 compounds, respectively. To explore the applications of these compounds in biosensing, in situ interaction studies between bromine oxidised compounds and biological cofactors nicotinamide adenine dinucleotide (NADH) and L-ascorbic acid (vitamin C) were carried out using optical absorption spectroscopy. Thin films of a non-peripherally octyl substituted LC lead phthalocyanine was exposed to 99.9 % pure hydrogen sulfide gas to produce hybrid nanocomposites consisting of lead sulphide quantum dots embedded in the analogous metal free phthalocyanine matrix. Trapping of charge carriers caused hysteresis in the current-voltage characteristics of the film on interdigitated gold electrodes. The charge hopping distance was found to be 9.05 nm, more than the percolation limit and responsible for forming two well-defined conducting states with potential application as a memristor

Steady state charge conduction through solution processed liquid crystalline lanthanide bisphthalocyanine films

In-plane electrical characteristics of non-peripherally octyl (C8H17) and hexyl (C6H13) substituted liquid crystalline (LC) double decker lanthanide bisphthalocyanine (LnPc2) complexes with central metal ions lutetium (Lu), and gadolinium (Gd) have been measured in thin film formulations on interdigitated gold (Au) electrodes for the applied voltage (V_a) range of 〖0 ≤ V〗_a ≤100 V. The conduction mechanism is found to be Ohmic within the bias of 〖0 ≤ V〗_a ≤30 V 0≤Va≤30 V while the bulk limited Poole-Frenkel mechanism is responsible for the higher bias. The compounds show individual characteristics depending on the central metal ions, substituent chain lengths and their mesophases. Values of 67.55 μS〖cm〗^(-1) and 42.31 μS〖cm〗^(-1) have been obtained. for room temperature in-plane Ohmic conductivity of as-deposited octyl lutetium (C8LuPc2) and hexyl gadolinium (C6GdPc2) films, respectively while C8GdPc2 films exhibit nearly two orders of magnitude smaller conductivity. On annealing at 80 ̊C, Ohmic conductivities of C8LuPc2 and C8GdPc2 are found to have increased but the conductivity of C6GdPc2 decreases by more than one order of magnitude to 1.5 μS〖cm〗^(-1). For physical interpretation of the charge transport behavior of these three molecules, their UV-visible optical absorption spectra have been studied in the solution and in as-deposited and annealed solid phases. It is believed that both orientational and positional reorganisations are responsible depending upon the size of the central ion and side chain length

Synthesis of N-(3-arylprop-2-ynyl)substituted olanzapine derivatives as potential inhibitors of PDE4B

The linkage between dopamine D2 receptors and PDE activity via cAMP prompted us to design a series of novel N-(3-arylprop-2-ynyl)substituted olanzapine derivatives as potential inhibitors of PDE4B. The target compounds were conveniently prepared by using a simple and inexpensive method involving Pd/C-mediated CC bond forming reaction under Sonogashira conditions. A number of compounds were synthesized by using this strategy in good yields. Some of the compounds showed promising inhibition of PDE4B when tested in vitro that was supported by the docking studies

A liquid crystalline copper phthalocyanine derivative for high performance organic thin film transistors

This journal is © The Royal Society of Chemistry 2012Bottom-gate, bottom-contact organic thin film transistors (OTFTs) were fabricated using solvent soluble copper 1,4,8,11,15,18,22,25-octakis(hexyl)phthalocyanine as the active semiconductor layer. The compound was deposited as 70 nm thick spin-coated films onto gold source–drain electrodes supported on octadecyltrichlorosilane treated 250 nm thick SiO2 gate insulators. The performance of the OTFTs was optimised by investigating the effects of vacuum annealing of the films at temperatures between 50 0C and 200 0C, a range that included the thermotropic mesophase of the bulk material. These effects were monitored by ultraviolet-visible absorption spectroscopy, atomic force microscopy and XRD measurements. Device performance was shown to be dependent upon the annealing temperature due to structural changes of the film. Devices heat treated at 100 0C under vacuum (≥10-7 mbar) were found to exhibit the highest field-effect mobility, 0.7 cm2 V^-1 s^-1, with an on–off current modulation ratio of~107, a reduced threshold voltage of 2.0 V and a sub-threshold swing of 1.11 V per decade.UK Technology Strategy Board (Project no: TP/6/EPH/6/S/K2536J) and UK National Measurement System (Project IRD C02 ‘‘Plastic Electronics’’, 2008–2011)

Genetic variation among species, races, forms and inbred lines of lac insects belonging to the genus Kerria (Homoptera, Tachardiidae)

The lac insects (Homoptera: Tachardiidae), belonging to the genus Kerria, are commercially exploited for the production of lac. Kerria lacca is the most commonly used species in India. RAPD markers were used for assessing genetic variation in forty-eight lines of Kerria, especially among geographic races, infrasubspecific forms, cultivated lines, inbred lines, etc., of K. lacca. In the 48 lines studied, the 26 RAPD primers generated 173 loci, showing 97.7% polymorphism. By using neighbor-joining, the dendrogram generated from the similarity matrix resolved the lines into basically two clusters and outgroups. The major cluster, comprising 32 lines, included mainly cultivated lines of the rangeeni form, geographic races and inbred lines of K. lacca. The second cluster consisted of eight lines of K. lacca, seven of the kusmi form and one of the rangeeni from the southern state of Karnataka. The remaining eight lines formed a series of outgroups, this including a group of three yellow mutant lines of K. lacca and other species of the Kerria studied, among others. Color mutants always showed distinctive banding patterns compared to their wild-type counterparts from the same population. This study also adds support to the current status of kusmi and rangeeni, as infraspecific forms of K. lacca

Maxillo-orbital granulocytic sarcoma in acute myeloid leukemia

Granulocytic sarcoma or chloroma, a manifestation of acute myeloid leukemia (AML) is a rare cause of childhood proptosis. A 14-year-old boy presented with progressively increasing unilateral proptosis and swelling of lower eyelid and face on the right side. Contrast enhanced computed tomographic images revealed enhancing infiltrates occupying the right orbit, maxillary antrum, and infratemporal fossa. Incisional biopsy from the orbital swelling and the bone marrow aspirate showing leukemic blast cells confirmed the diagnosis of AML. The peripheral smear was normal initially, but high total leukocytic count with immature blast cells was evident after 1-month of presentation. Chemotherapy brought about the remission of the disease. However, the delay in diagnosis because of negative peripheral blood smear examination and inconclusive fine-needle aspiration biopsy led to the loss of vision in right eye. Diagnosis of such case can be made by a combination of good clinical examination and relevant investigations. This case of maxillo-orbital granulocytic sarcoma is reported because of its rarity and to emphasize the clinical and cyto-histological features and problems concerning differential diagnosis

QSAR with electrotopological state atom index:Part II^†-Antimalarial activity of dihydroqinghaosu derivatives^‡

587-595QSAR analysis of antimalarial activity of some ester and ether derivatives (AR1-AR21) of dihydroqinghaosu (dihydroartemisinin) has been done with electrotopological state atom (ETSA) index in an attempt to explore the atoms or fragments of the molecules that are most important for the mediation of the activity. The study reveals the importance of the oxygen atoms (including those of the peroxide bridge) of artemisinin skeletal ring structure and the lactol oxygen. The observation corroborates an earlier finding that reduction of the peroxide bridge of artemisinin resulting in loss of one oxygen reduces the activity. It was previously suggested that artemisinin and related compounds might kill the parasites by a free radical mediated process and the peroxide bridge might play a crucial role in the mechanism. Further, that the dihydro form (of the lactone moiety) of artemisinin is more active is also traced to the importance of the corresponding lactol oxygen atom in the present QSAR study. Thus, diagnostic potential of the ETSA scheme in identifying the atoms or fragments important for activity is revealed from the study. The study further suggests that α configuration of the lactol oxygen is preferred. The ether / ester side chain should be of less bulk and preferably with oxo functionality. Presence of branchedness and alicyclic ring in the side chain has negative contributions to the activity

Hansch analysis of anticancer activities of C2-modified paclitaxel analogs against human ovarian carcinoma 1A9, human colon carcinoma HCT116 and human burkitt lymphoma CA46 cell lines

1194-1202Anticancer activities, recently reported by Kingston et al, of paclitaxel and its thirty analogs, having substitution(s) on the phenyl ring of 2-benzoyloxy moiety, against human ovarian carcinoma 1A9, human colon carcinoma HCT116 and human burkitt lymphoma CA46 cell lines have been subjected to QSAR analyses by extrathermodynamic approach of Hansch. The aims of the study are to explore the effects of the phenyl ring substituents on the activities and to unravel the quantitative relations of the activities with physico-chemical parameters of the substituents. For the activity against ovarian carcinoma, presence of meta and absence of para substituents on the phenyl ring (with Respect to the ester linkage on the 2-position of taxane skeleton) has been found to be conducive to the activity. Molar refractivity and electronic parameter (Hammett ϭ ) of the meta substituents show parabolic relationships with the activity. In case of the activity against colon carcinoma, para substitution is not preferred. However, Iipophilicity of the para substituent, If present, has been found to favour to the activity which was further negatively contributed by square term of molar refractivity of the meta substituents. In the relation best obtained, the activity against burkitt lymphoma is found to be negatively contributed by square term of molar refractivity of the meta substituents and those of electronic parameters (Hammett ϭ) of the para and meta substituents. The differences among the equations relating activity against three cell lines with physico-chemical parameters suggest that there might be some differences among the receptor structures

Comparative QSAR studies with molecular negentropy, molecular connectivity, STIMS and TAU indices: Part II — General anaesthetic activity of aliphatic hydrocarbons, halocarbons and ethers^†

129-135General anaesthetic activity of two sets of compounds, one (set A) comprising twenty seven aliphatic ethers and the other (set B) consisting of twenty one heterofunctional compounds (aliphatic hydrocarbons, halocarbons and ethers) is subjected to quantitative structure activity relationship studies with various topological indices and the relations are compared with atopological index Nv (vertex count). The relations of the activity of set A compounds with molecular connectivity index 1v (EV 83.4%), TAU (EV 79.7-83.9%) and STIMS (EV 77.3- 84.8%) indices are comparable to that of Nv (EV 80.8%) while molecular negentropy I (EV 72.8%) showed somewhat inferior relation. In case of set B, Nv and I did not produce statistically acceptable relations while TAU indices explained 66.9-85.6% variation in the activity. The study reveals that the activity increases with the increase in Nv (molecular bulk) and functionality F (in case of set B) and decreases as the branchedness increases. Important contributions of branchedness, shape factors (STIMS like NX, NY and NB) and functionality F (in set B) towards the activity suggest that the non-specific nature of general anaesthetic action requires further evaluation

Hepatoprotective and Antioxidant Potential of Phenolics-Enriched Fraction of Anogeissus acuminata Leaf against Alcohol-Induced Hepatotoxicity in Rats

Anogeissus acuminata is used to treat wounds, diarrhoea, dysentery, and skin ailments. However, its hepatoprotective effect against ethanol-induced liver damage is yet to be reported. The phenolic-enriched ethyl acetate fraction of Anogeissus acuminata (AAE) was evaluated for hepatoprotective activity against ethanol-induced liver toxicity in rats. The intoxicated animals were treated with a phenolic-rich fraction of Anogeissus acuminata (AAE) (100 and 200 mg/kg) and silymarin (100 mg/kg). The antioxidant activity of AAE was analysed. Biochemical markers (ALT, AST, ALP, GGT, and TBL) for liver injury in ethanol-administered animals resulted in higher levels of key serum biochemical injury markers, as evidenced by increased levels of ALT (127.24 ± 3.95), AST (189.54 ± 7.56), ALP (263.88 ± 12.96), GGT (91.65 ± 3.96), and TBL (2.85 ± 0.12) compared to Group I ALT (38.67 ± 3.84), AST (64.45 ± 5.97), GGT (38.67 ± 3.84), and TBL (0.53 ± 064) (p < 0.05). AAE administration decreased serum biochemical liver injury markers as manifested in Group III animals’ ALT (79.56 ± 5.16), AST (151.76 ± 6.16), ALP (184.67 ± 10.12), GGT (68.24 ± 4.05), TBL (1.66 ± 0.082) (p < 0.05), and Group IV ALT (55.54 ± 4.35), AST (78.79 ± 4.88), ALP (81.96 ± 9.43), GGT (47.32 ± 2.95), TBL (0.74 ± 0.075) (p < 0.05). Group IV exhibited the most significant reduction in serum biochemical markers as compared to Group III (p < 0.05) and close to silymarin-treated Group V ALT (44.42 ± 3.15), AST (74.45 ± 5.75), ALP (67.32 ± 9.14), GGT (42.43 ± 2.54), TBL (0.634 ± 0.077). Gene expression indices and histoarchitecture were evaluated to demonstrate the potential of AAE. The bioactive fraction of Anogeissus acuminata was rich in phenolics and flavonoid content. GC–MS analysis identified gallic acid, palmitic acid, cis-10-heptadecenoic acid, 9-octadecenoic acid, epigallocatechin, 2,5-dihydroxyacetophenone, and catechin. Oral administration of AAE (100 and 200 mg/kg) lowered the elevated levels of the biochemical markers and interleukin, and enhanced the level of enzymatic antioxidant. It also downregulated the expression level of proapoptotic genes and upregulated the expression level of the antiapoptotic gene along with improved liver histopathology