Supramolecular Recognition within a Nanosized "Buckytrap" That Exhibits Substantial Photoconductivity.

We report here a nanosized "buckytrap", 1, constructed from two bis-zinc(II) expanded-TTF (exTTF) porphyrin subunits. Two forms, 1a and 1b, differing in the axial ligands, H2O vs tetrahydrofuran (THF), were isolated and characterized. Discrete host-guest inclusion complexes are formed upon treatment with fullerenes as inferred from a single-crystal X-ray structural analyses of 1a with C70. The fullerene is found to be encapsulated within the inner pseudohexagonal cavity of 1a. In contrast, the corresponding free-base derivative (2) was found to form infinite ball-and-socket type supramolecular organic frameworks (3D-SOFs) with fullerenes, (2•C60)n or (2•C70)n. This difference is ascribed to the fact that in 1a and 1b the axial positions are blocked by a H2O or THF ligand. Emission spectroscopic studies supported a 1:1 host-guest binding stoichiometry, allowing association constants of (2.0 ± 0.5) × 104 M-1 and (4.3 ± 0.9) × 104 M-1 to be calculated for C60 and C70, respectively. Flash-photolysis time-resolved microwave conductivity (FP-TRMC) studies of solid films of the Zn-complex 1a revealed that the intrinsic charge carrier transport, i.e., pseudo-photoconductivity (ϕ∑µ), increases upon fullerene inclusion (e.g., ϕ∑µ = 1.53 × 10-4 cm2 V-1 s-1 for C60⊂(1a)2 and ϕ∑µ = 1.45 × 10-4 cm2 V-1 s-1 for C70⊂(1a)2 vs ϕ∑µ = 2.49 × 10-5 cm2 V-1 s-1 for 1a) at 298 K. These findings provide support for the notion that controlling the nature of self-assembly supramolecular constructs formed from exTTF-porphyrin dimers through metalation or choice of fullerene can be used to regulate key functional features, including photoconductivity.

Oligopyrrolic Cages: From Classic Molecular Constructs to Chemically Responsive Polytopic Receptors.

"Functional molecular systems", discrete and self-assembled constructs where control over molecular recognition, structure, bonding, transport, release, catalytic activity, etc., is readily achieved, are a topic of current interest. Within this broad paradigm, oligopyrrolic cages have garnered attention due to their responsive recognition features. Due to the presence of slightly polar pyrrole subunits which can also behave as hydrogen-bonding donors, these oligopyrrolic cages are potential receptors for various polarized species. In this Account, we summarize recent advances involving the syntheses and study of (1) covalent oligopyrrolic macrobicyclic cages, (2) oligopyrrolic metallacages, and (3) oligopyrrolic noncovalently linked cages. Considered in concert, these molecular constructs have allowed advances in applied supramolecular chemistry; to date, they have been exploited for selective guest encapsulation studies, anion binding and ion-channel formation, and gas absorption, among other applications. While key findings from others will be noted, in this Account will focus on our own contributions to the chemistry of discrete oligopyrrolic macrocycles and their use in supramolecular host-guest chemistry and sensing applications. In terms of specifics, we will detail how oligopyrrole cages with well-defined molecular geometries permit reversible guest binding under ambient conditions and how the incorporation of pyrrole subunits within larger superstructures allows effective control over anion/conjugate acid binding activity under ambient conditions. We will also provide examples that show how derivatization of these rudimentary macrocyclic cores with various sterically congested ß-substituted oligopyrroles can provide entry into more complex supramolecular architectures. In addition, we will detail how hybrid systems that include heterocycles other than pyrrole, such as pyridine and naphthyridine, can be used to create self-assembled materials that show promise as gas-absorbing materials and colorimetric reversible sensors. Studies involving oligopyrrolic polymetallic cages and oligopyrrolic supramolecular cages will also be reviewed. First, we will discuss all-carbon-linked oligopyrrolic bicycles and continue on to present systems linked via amines and imines linkages. Finally, we will summarize recent work on pyrrolic cages created through the use of metal centers or various noncovalent interactions. We hope that this Account will provide researchers with an initial foundation for understanding oligopyrrolic cage chemistry, thereby allowing for further advances in the area. It is expected that the fundamental design and recognition principles made in the area of oligopyrrole cages, as exemplified by our contributions, will be of general use to researchers targeting the design of functional molecular systems. As such, we have structured this Account so as to summarize the past while setting the stage for the future.

Solid-State Synthesis and Optical Studies of Water-Stable Pb2+-Doped Mn2+ Complexes.

The limited Mn2+ doping that occurs in lead halide perovskites has been widely described, while the Pb2+ doping that occurs in Mn2+ halide perovskites has not been studied well. Generally, a large amount of doping of Mn2+ in lead halide perovskite degrades the perovskite structure; eventually, high orange luminescence of Mn2+ dopant has not been achieved. In our present study, we followed a reverse strategy, i.e., Pb2+ doping in Mn2+ halide perovskites, to increase the amount of Mn2+ in halide perovskites through the high-energy ball milling method. This strategy yields bright-fluorescence orange light-emitting Mn2+-doped perovskite with a Mn/Pb ratio of 95%, which is the highest among Mn2+-doped perovskites. Zero-dimensional (0D) Mn2+ perovskites and two-dimensional (2D) Pb2+-doped Mn2+-based perovskites were successfully synthesized and characterized. During the mechanochemical engineering, Pb2+ ions partially occupy the site of Mn2+ ions and act as a luminescence activator. Mn2+-based 2D perovskites with the proper amounts of Pb2+ ions as dopant ions and phenylethylammonium (PEA+) as dielectric organic cations show enhanced stability in water. The dual-emissive properties of these 2D-Pb2+-doped Mn2+-based perovskites were also investigated by using single-particle imaging fluorescence. We believe that these findings will pave the way for designing eco-friendly dimension and bandgap tunable layered perovskites.

Progress and challenges of graphene and its congeners for biomedical applications.

Nanomaterials by virtue of their small size and enhanced surface area, present unique physicochemical properties that enjoy widespread applications in bioengineering, biomedicine, biotechnology, disease diagnosis, and therapy. In recent years, graphene and its derivatives have attracted a great deal of attention in various applications, including photovoltaics, electronics, energy storage, catalysis, sensing, and biotechnology owing to their exceptional structural, optical, thermal, mechanical, and electrical. Graphene is a two-dimensional sheet of sp2 hybridized carbon atoms of atomic thickness, which are arranged in a honeycomb crystal lattice structure. Graphene derivatives are graphene oxide (GO) and reduced graphene oxide (rGO), which are highly oxidized and less oxidized forms of graphene, respectively. Another form of graphene is graphene quantum dots (GQDs), having a size of less than 20 nm. Contemporary graphene research focuses on using graphene nanomaterials for biomedical purposes as they have a large surface area for loading biomolecules and medicine and offer the potential for the conjugation of fluorescent dyes or quantum dots for bioimaging. The present review begins with the synthesis, purification, structure, and properties of graphene nanomaterials. Then, we focussed on the biomedical application of graphene nanomaterials with special emphasis on drug delivery, bioimaging, biosensing, tissue engineering, gene delivery, and chemotherapy. The implications of graphene nanomaterials on human health and the environment have also been summarized due to their exposure to their biomedical applications. This review is anticipated to offer useful existing understanding and inspire new concepts to advance secure and effective graphene nanomaterials-based biomedical devices.

Benzo-Tetrathiafulvalene- (BTTF-) Annulated Expanded Porphyrins: Potential Next-Generation Multielectron Reservoirs.

Two sterically crowded benzo-tetrathiafulvalene (BTTF)-annulated expanded porphyrins (BTTF7-F and BTTF8) are synthesized. Detailed photophysical investigations reveal their intrinsic intramolecular charge transfer (CT) character, originated from partial electron transfer from electron-rich TTF units to the relatively electron-deficient macrocyclic core. This finding stands in contrast to what was observed in the previously reported Figure-of-eight conformer of BTTF-annulated [28]hexaphyrin (BTTF6), in which a typical π-π* electronic transition from HOMO to LUMO was observed. However, core expansion in BTTF7-F and BTTF8 makes the oligopyrrole macrocyclic cores relatively more electron-deficient, facilitating the effective intramolecular CT process. Comparative electrochemical investigations reveal that the current generated at the oxidative region is directly proportional to the number of TTF units attached to the macrocyclic core. This work demonstrates the control of the intramolecular CT process through incremental addition of TTF units to the macrocyclic core. Facile multielectron electrochemical oxidations of these expanded porphyrins suggest that they behave like potential multielectron reservoirs.

Solvent-Regulated Fluorimetric Differentiation of Al3+ and Zn2+ Using an AIE-Active Single Sensor.

The absence of d-orbital electrons or presence of full-filled d-orbital electrons in metal ions is a well-known Achilles' heel problem for the detection of these metal ions by a simple UV-visible study. For this reason, detection of metal ions such as Al3+ with no d-orbital electrons or Zn2+ with filled d-orbital electrons is a challenging task. Herein, we report a 2-naphthol-based fluorescent probe [1-((E)-((E)-(5-bromo-2-hydroxybenzylidene)hydrazono)methyl)naphthalen-2-ol] (H2L) that has been used to sense and discriminate Al3+ and Zn2+ via solvent regulation. The probe exhibits excellent selectivity and swift sensitivity toward Al3+ in MeOH-water (9:1, v/v) and toward Zn2+ in dimethyl sulfoxide (DMSO)-water (9:1, v/v) among various metal ions. The respective detection limit is found to be 9.78 and 3.65 µM. The sensing mechanism is attributed to multiple processes, viz., the inhibition of photo-induced electron transfer (PET) along with the introduction of chelation-enhanced emission (CHEF) and excited-state intramolecular proton transfer (ESIPT) inhibition, which are experimentally well verified by UV-vis absorption spectroscopy, emission spectroscopy, and NMR spectroscopy. The probe shows aggregation-induced emissive (AIE) response in ≥70% aqueous media as well as in the solid state. The experimental results are well corroborated by time-resolved photoluminescence (TRPL) and density functional theory (DFT) calculations. An advanced-level OR-AND-NOT logic gate has been constructed from a different chemical combinational input and emission output. The reversible recognition of both Al3+ in MeOH-water (9:1, v/v) and Zn2+ in DMSO-water (9:1, v/v) is also ascertained in the presence of Na2EDTA, enabling the construction of a molecular memory device. The probe H2L also detects intracellular Al3+/Zn2+ ions in Hela cells. Altogether, our fundamental findings will pave the way for designing and synthesis of unique chemosensors that could be used for cell imaging studies as well as constructing molecular logic gates.

Solvent-Controlled Self-Assembled Oligopyrrolic Receptor.

We report a fully organic pyridine-tetrapyrrolic U-shaped acyclic receptor 10, which prefers a supramolecular pseudo-macrocyclic dimeric structure (10)2 in a less polar, non-coordinating solvent (e.g., CHCl3). Conversely, when it is crystalized from a polar, coordinating solvent (e.g., N,N-dimethylformamide, DMF), it exhibited an infinite supramolecular one-dimensional (1D) "zig-zag" polymeric chain, as inferred from the single-crystal X-ray structures. This supramolecular system acts as a potential receptor for strong acids, e.g., p-toluenesulfonic acid (PTSA), methane sulfonic acid (MSA), H2SO4, HNO3, and HCl, with a prominent colorimetric response from pale yellow to deep red. The receptor can easily be recovered from the organic solution of the host-guest complex by simple aqueous washing. It was observed that relatively stronger acids with pKa < -1.92 in water were able to interact with the receptor, as inferred from 1H NMR titration in tetrahydrofuran-d8 (THF-d8) and ultraviolet-visible (UV-vis) spectroscopic titrations in anhydrous THF at 298 K. Therefore, this new dynamic supramolecular receptor system may have potentiality in materials science research.

Self-Assembled Cagelike Receptor That Binds Biologically Relevant Dicarboxylic Acids via Proton-Coupled Anion Recognition.

We report here a fully organic, self-assembled dimeric receptor, constructed from acyclic naphthyridyl-polypyrrolic building blocks. The cagelike dimer is stable in the solid state, in solution, and in gas phase, as inferred from X-ray diffraction and spectroscopic analyses. This system acts as a receptor for oxalic acid, maleic acid, and malonic acid in the solid state and in THF solution. In contrast, acetic acid, propionic acid, adipic acid, and succinic acid, with pKa values > ca. 2.8, were not bound effectively within the cagelike cavity. It is speculated that oxalic acid, maleic acid, and malonic acid serve to protonate the naphthyridine moieties of the host, which then favors binding of the corresponding carboxylate anions via hydrogen-bonding to the pyrrolic NH protons. The present naphthyridine-polypyrrole dimer is stable under acidic conditions, including in the presence of 100 equiv trifluoroacetic acid (TFA), p-toluenesulfonic acid (PTSA), H2SO4, and HCl. However, disassembly may be achieved by exposure to tetrabutylammonium fluoride (TBAF). Washing with water then regenerates the cage. This process of assembly and disassembly could be repeated >20 times with little evidence of degradation. The reversible nature of the present system, coupled with its dicarboxylic acid recognition features, leads us to suggest it could have a role to play in effecting the controlled "capture" and "release" of biologically relevant dicarboxylic acids.

Semiconducting Supramolecular Organic Frameworks Assembled from a Near-Infrared Fluorescent Macrocyclic Probe and Fullerenes.

We report here a new extended tetrathiafulvalene (exTTF)-porphyrin scaffold, 2, that acts as a ball-and-socket receptor for C60 and C70. Supramolecular interactions between 2 and these fullerenes serve to stabilize 3D supramolecular organic frameworks (SOFs) in the solid state formally comprising peapod-like linear assemblies. The SOFs prepared via self-assembly in this way act as "tunable functional materials", wherein the complementary geometry of the components and the choice of fullerene play crucial roles in defining the conductance properties. The highest electrical conductivity (σ = 1.3 × 10-8 S cm-1 at 298 K) was observed in the case of the C70-based SOF. In contrast, low conductivity was seen for the SOF based on pristine 2 (σ = 5.9 × 10-11 S cm-1 at 298 K). The conductivity seen for the C70-based SOF approaches that seen for other TTF- and fullerene-based supramolecular materials despite the fact that the present systems are metal-free and constructed entirely from neutral building blocks. Transient absorption spectroscopic measurements corroborated the formation of charge-transfer states (i.e., 2δ+/C60δ- and 2δ+/C70δ-, respectively) rather than fully charge separated states (i.e., 2•+/C60•- and 2•+/C70•-, respectively) both in solution (toluene and benzonitrile) and in the solid state at 298 K. Such findings are considered consistent with an ability to transfer charges effectively over long distances within the present SOFs, rather than, for example, the formation of energetically trapped ionic species.

Detection of Trace-Level Nitroaromatic Explosives by 1-Pyreneiodide-Ligated Luminescent Gold Nanostructures and Their Forensic Applications.

By attaching the1-pyreneiodide ancillary ligand to the surface of polyvinylpyrrolidone-stabilized gold (Au:PVP) cluster or the cetyltrimethyl ammonium bromide-stabilized gold (Au:CTAB) nanorod, a new class of luminescent mixed ligand-stabilized gold nanostructures is synthesized. This postsynthetic surface modification method followed by us is a comparatively easier and hassle-free technique to acquire surface-active luminescent "functional nanomaterials". Careful analyses of transmission electron microscopy images revealed that the sizes of these Au-clusters or Au-nanorods remain unchanged without any noticeable aggregation in the medium. Owing to the formation of an excimer within the neighboring pyrenes mounted on the surface of core nanostructures (i.e., Au:PVP nanocluster and Au:CTAB nanorod), the resulting pyrene-grafted nanocomposites exhibit strong emission characteristics. The strong excimer emission is significantly quenched in the presence of electron-deficient chemical inputs, and this phenomenon can be used for analytical purposes. Using these luminescent Au-nanomaterials, we demonstrate a selective detection and sensing of trace-level nitroaromatic explosives (e.g., trinitrotoluene, trinitrophenol (TNP), dinitrotoluene, 4-nitrotoluene, etc.). It was observed that the Py-Au:PVP nanocluster is equally effective for explosive detection in both solution and solid phases with the limit of detection up to 10 nanomolar. A high Stern-Volmer constant of up to 3.88 × 106 M-1 was seen in the case of TNP in anhydrous methanol at 298 K. The deactivation pathway operating within the Py-Au:PVP nanocluster and the analytes is thought to be a result of a predominating static quenching process, where a nonfluorescent D-A supramolecular adduct is formed in the medium. Py-Au:PVP has also been successfully used to develop latent fingerprints from nonporous surfaces under an exposure of 365 nm UV light. The results suggest that these new composite materials could behave as potential "functional nanomaterials", which might be a promising alternative for on-the-spot detection of explosive traces as well as for easy visualization of latent fingerprints.

Tetrathiafulvalene- (TTF-) Derived Oligopyrrolic Macrocycles.

After the epochal discovery of the "organic metal", namely, tetrathiafulvalene (TTF)-7,7,8,8-tetracyano-p-quinodimethane (TCNQ) dyad in 1973, scientists have made efforts to derivatize TTF for constructing various supramolecular architectures to control the charge-transfer processes by adjusting the donor-acceptor strength of the dyads for numerous applications. The interesting inherent electronic donor properties of TTFs control the overall electrochemical properties of the supramolecular structures, leading to the construction of highly efficient optoelectronic materials, photovoltaic solar cells, organic field-effect transistors, and optical sensors. Modified TTF structures thus constitute promising candidates for the development of so-called "functional materials" that could see use in modern technological applications. The versatility of the TTF unit and the pioneering synthetic strategies that have been developed over the past few decades provide opportunities to tune the architecture and function for specific purposes. This review covers the "state of the art" associated with TTF-annulated oligopyrrolic macrocyclic compounds. Points of emphasis include synthesis, properties, and potential applications.

Neurodevelopmental Outcomes of Very Low Birth Weight Infants at 18-24 Months, Corrected Gestational Age in a Tertiary Health Centre: A Prospective Cohort Study.

OBJECTIVE: To determine the prevalence and risk factors for poor neurodevelopmental outcome in a cohort of very low birth weight (VLBW) infants. SUBJECTS AND METHODS: Four hundred and twenty-two infants of a total of 643 VLBW survivors from a teaching hospital in South India were followed up to assess their neurodevelopmental outcomes. RESULTS: Among the 422 children who completed the assessment, results of 359 children whose assessments were done between 18 and 24 months were analysed. Thirty-seven children (10.31%) had poor neurodevelopmental outcome, six children [1.67%] had cerebral palsy, one child had visual impairment and another had hearing impairment. Poor post-natal growth was independently associated with poor neurodevelopmental outcomes in the multivariate analysis (p = 0.045). Neonatal complications were not associated with the developmental outcome. CONCLUSION: Despite lower rates of neonatal complications compared with Western cohorts, significant proportion of VLBW infants had poor neurodevelopmental outcomes. Poor post-natal growth was an important determinant of the developmental outcome.

Functionalised tetrathiafulvalene- (TTF-) macrocycles: recent trends in applied supramolecular chemistry.

Tetrathiafulvalene (TTF) has been extensively explored as a π-electron donor in supramolecular systems. Over the last two decades substantial advances have been made in terms of constructing elaborate architectures based on TTF and in exploiting the resulting systems in the context of supramolecular host-guest recognition. The inherent electron-donating character of TTF derivatives has led to their use in the construction of highly efficient optoelectronic materials, optical sensors, and electron-transfer ensembles. TTFs are also promising candidates for the development of the so-called "functional materials" that might see use in a range of modern technological applications. Novel synthetic strategies, coupled with the versatility inherent within the TTF moiety, are now allowing the architecture of TTF-based systems to be tuned precisely and modified for use in specific purposes. In this critical review, we provide a "state-of-the-art" overview of research involving TTF-based macrocyclic systems with a focus on their use in supramolecular host-guest recognition, as components in non-covalent electron transfer systems, and in the construction of "molecular machines".

Perinatal Risk Factors for Neonatal Early-onset Group B Streptococcal Sepsis after Initiation of Risk-based Maternal Intrapartum Antibiotic Prophylaxis-A Case Control Study.

OBJECTIVES: To identify the perinatal risk factors for early-onset Group B Streptococcus (EOGBS) sepsis in neonates after inception of a risk-based maternal intrapartum antibiotic prophylaxis strategy in 2004. DESIGN: Case control study. METHODS: All newborn with early onset GBS sepsis (born between 2004 and 2013) were deemed to be "cases" and controls were selected in a 1:4 ratio. RESULTS: More than three per vaginal (PV) examinations [odds ratio (OR) 8.57, 95% confidence interval (CI) 3.10-23.6] was a significant risk factors. Peripartum fever (OR 3.54, 95% CI 1.3-9.67), urinary tract infection (OR 2.88, 95% CI 1.08-7.63), meconium-stained amniotic fluid (MSAF) (OR 2.52, 95% CI 1.18-5.37) and caesarean section (OR 1.99, 95% CI 1.16-3.43) were also found to be associated with EOGBS sepsis. CONCLUSION: Multiple vaginal examinations are the strongest risk factors for peripartum Group B Streptococcal (GBS) sepsis. The association of MSAF and caesarean section indicates that foetal distress is an early symptom of perinatal GBS infection.

Pt(II)C∧N∧N-Based Luminophore-Micelle Adducts for Sensing Nitroaromatic Explosives.

Two luminescent cyclometalated Pt(II)-complexes, 1•Pt and 2•Pt, respectively, were synthesized by using unsymmetrical C∧N∧N ligands having different alkyl substituents. These π-electron-rich complexes are used for sensing various electron deficient nitroaromatic explosives, e.g., 4-nitrotoluene (NT), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), and 2,4,6-trinitrophenol (TNP), in aqueous, nonaqueous, as well as in the solid state as a paper strip with maximum detection limit of ca. 10-9 M. It was demonstrated that the sparingly soluble 2•Pt complex becomes water-soluble in the presence of all kinds of surfactants, viz., cationic (e.g., cetyltrimethylammonium bromide, CTAB), anionic (e.g., sodium dodecyl sulfate, SDS), and neutral (e.g., Triton X-100). This may be due to the incorporation of its long lyophilic tail group (-C12H25) inside the micellar core, exposing planar Pt(II)C∧N∧N headgroup to the aqueous bulk phase. It was also observed that the extent of solubility of these Pt(II)-complexes in micellar media strongly depends on the length of the existing alkyl chain. For instance, the presence of longer dodecyl chain makes 2•Pt complex ca. 1000-fold more soluble than the complex 1•Pt, which contains a shorter propyl chain. Their sensing behavior essentially arises by the quenching of Pt(II)-based intense luminescence due to the supramolecular charge transfer (CT) process originating from Pt(II)C∧N∧N-antenna to the electron deficient nitroaromatic explosives. Our present work shows that the micellar adducts formed by highly luminophoric material and surfactant molecules could effectively detect such explosives in aqueous medium with better sensitivity compared to what were observed in other media.

Influence of using a blend of rennet casein and whey protein concentrate as protein source on the quality of Mozzarella cheese analogue.

The effect of incorporating whey protein concentrate (WPC) on the quality characteristics of Mozzarella cheese analogue (MCA) based on rennet casein (RC) was studied. The proportion of RC:WPC tried out were 95:5, 90:10, and 85:15 w/w. The formulation of MCA comprised of 23.5% of blend of RC and WPC, 15% specialty vegetable fat, 2.75% trisodium citrate + disodium hydrogen orthophosphate (2.5:1, w/w), 0.07% calcium chloride, 0.6% citric acid, 1.1% NaCl, 1.5% cheese bud flavoring, and rest water. Varying the proportion of RC and WPC had a significant influence on the composition, textural properties, baking qualities and sensory quality of MCA judged as a topping on pizza pie. MCA made using protein blends (RC:WPC-90:10 or 85:15) behaved satisfactorily during pizza baking trials. However, looking at the superiority of MCA made using RC:WPC (90:10) with regard to shred quality and marginal superiority in terms of the total sensory score of cheese, judged as pizza topping, the former blend (i.e. RC:WPC, 90:10) was selected. The MCA obtained employing such protein blend had composition similar to that of Pizza cheese prepared from cheese milk and had requisite baking characteristics needed as a pizza topping. It is recommended to use a blend of RC and WPC (90:10) as the protein source in the formulation of MCA to obtain nutritionally superior cheese product having desired functional properties for its end use in baking applications.

Porphyrin/Platinum(II) C

A new class of substituted porphyrins has been developed in which a different number of cyclometalated Pt(II) C^N^N acetylides and polyethylene glycol (PEG) chains are attached to the meso positions of the porphyrin core, which are meant for photophysical, electrochemical, and in vitro light-induced singlet oxygen ((1)O2) generation studies. All of these Zn(II) porphyrin-Pt(II) C^N^N acetylide conjugates show moderate to high (ΦΔ =0.55 to 0.63) singlet oxygen generation efficiency. The complexes are soluble in organic solvents but, despite the PEG substituents, slowly aggregate in aqueous solvent systems. These conjugates also exhibit interesting photophysical properties, including near-complete photoinduced energy transfer (PEnT) through the rigid acetylenic bond(s) from the Pt(II) C^N^N antenna units to the Zn(II) porphyrin core, which shows sensitized luminescence, as shown by quenching of Pt(II) C^N^N-based luminescence. Electrochemical measurements show a set of redox processes that are approximately the sum of what is observed for the Pt(II) C^N^N acetylide and Zn(II) porphyrin units. UV/Vis spectroscopic properties are supported by DFT calculations.

Heteronuclear Ir(III)-Ln(III) Luminescent Complexes: Small-Molecule Probes for Dual Modal Imaging and Oxygen Sensing.

Luminescent, mixed metal d-f complexes have the potential to be used for dual (magnetic resonance imaging (MRI) and luminescence) in vivo imaging. Here, we present dinuclear and trinuclear d-f complexes, comprising a rigid framework linking a luminescent Ir center to one (Ir·Ln) or two (Ir·Ln2) lanthanide metal centers (where Ln = Eu(III) and Gd(III), respectively). A range of physical, spectroscopic, and imaging-based properties including relaxivity arising from the Gd(III) units and the occurrence of Ir(III) → Eu(III) photoinduced energy-transfer are presented. The rigidity imposed by the ligand facilitates high relaxivities for the Gd(III) complexes, while the luminescence from the Ir(III) and Eu(III) centers provide luminescence imaging capabilities. Dinuclear (Ir·Ln) complexes performed best in cellular studies, exhibiting good solubility in aqueous solutions, low toxicity after 4 and 18 h, respectively, and punctate lysosomal staining. We also demonstrate the first example of oxygen sensing in fixed cells using the dyad Ir·Gd, via two-photon phosphorescence lifetime imaging (PLIM).

Comparison of neonatal outcomes in women with gestational diabetes with moderate hyperglycaemia on metformin or glibenclamide--a randomised controlled trial.

BACKGROUND: Two oral hypoglycaemic agents, metformin and glibenclamide, have been compared with insulin in separate large randomised controlled trials and have been found to be as effective as insulin in gestational diabetes. However, very few trials have compared metformin with glibenclamide. MATERIALS AND METHODS: Of 159 South Indian women with fasting glucose ≥5.5 mmol/l and ≤7.2 mmol/l and/or 2-h post-prandial value ≥6.7 mmol/l and ≤13.9 mmol/l after medical nutritional therapy consented to be randomised to receive either glibenclamide or metformin. 80 women received glibenclamide and 79 received metformin. Neonatal outcomes were assessed by neonatologists who were unaware that the mother was part of a study and were recorded by assessors blinded to the medication the mother was given. The primary outcome was a composite of neonatal outcomes namely macrosomia, hypoglycaemia, need for phototherapy, respiratory distress, stillbirth or neonatal death and birth trauma. Secondary outcomes were birthweight, maternal glycaemic control, pregnancy induced hypertension, preterm birth, need for induction of labour, mode of delivery and complications of delivery. RESULTS: Baseline characteristics were similar but for the higher fasting triglyceride levels in women on metformin. The primary outcome was seen in 35% of the glibenclamide group and 18.9% of the metformin group [95% CI 16.1 (2.5, 29.7); P = 0.02]. The difference in outcome related to a higher rate of neonatal hypoglycaemia in the glibenclamide group (12.5%) versus none in the metformin group [95% CI 12.5(5.3, 19.7); P = 0.001]. Secondary outcomes in both groups were similar. CONCLUSION: In a south Indian population with gestational diabetes, metformin was associated with better neonatal outcomes than glibenclamide.

A novel 2,6-diformyl-4-methylphenol based chemosensor for Zn(II) ions by ratiometric displacement of Cd(II) ions and its application for cell imaging on human melanoma cancer cells.

A new chelating ligand [4-methyl-2,6-bis-(pyridin-2-yl-hydrazonomethyl)-phenol] (1) was prepared by the condensation of 2-hydrazinylpyridine with 2,6-diformyl-p-cresol. Compound 1 exhibits weak fluorescence due to intramolecular photoinduced electron transfer (PET). The sensor (1) demonstrates Zn(2+)-specific emission enhancement due to the "PET off" process through a 1:1 binding mode with the metal ion. The fluorescence quantum yield of chemosensor 1 is only 0.020, and it increases more than 14-fold (0.280) in the presence of one equivalent of the zinc ion. Interestingly, the introduction of other metal ions causes the fluorescence intensity to remain either unchanged or weakened except for Cd(2+). The new sensor showed 'naked-eye' detection of Zn(2+) ions: a color change of the solution from colorless to yellow. Ratiometric displacement of Cd(2+) ions from the complex by Zn(2+) ions supports the formation of a more stable sensor­Zn(2+) complex over the sensor­Cd(2+) complex. The experimental findings have been correlated with theoretical results using the B3LYP functional and 6-31G (d, p), LANL2DZ basis set for Cd(2+) (2) and Zn(2+) (3) complexes, respectively, by the Density Functional Theory (DFT) method. Moreover, the ability of probe 1 to sense Zn(2+) within human melanoma cancer cells has been explored, and the Zn(2+)-probing process in living cells was found to be reversible with zinc chelator solution of N,N,N,N-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) or EDTA.