Organolead Research Articles

Perovskite Photovoltaics: Rare Functions of Organo Lead Halide in Solar Cells and Optoelectronic Devices

Abstract Organo-lead halide perovskite compounds, otherwise called organic–inorganic hybrid perovskite, represented by CH3NH3PbI3, exhibit many rare functions as narrow-band-gap semiconductors that are superior in applications for photovoltaic power conversion as well as for high-gain photon-mode detection of visible light. In this review, photoelectric properties of solution-processed CH3NH3PbI3 films and future perspectives in low-cost device fabrication are discussed based on our investigations.

Gamma-ray spectroscopy and pulse shape discrimination with a plastic scintillator

The scintillation properties of a novel plastic scintillator loaded with an organolead compound are presented. Under X-ray and gamma-ray excitation, emission is observed peaking at 435nm. The scintillation light output is 9000ph/MeV. An energy resolution (full width at half maximum over the peak position) of about 16% was observed for the 662keV full absorption peak. Excellent pulse shape discrimination between neutrons and gamma-rays with a Figure of Merit of 2.6 at 1MeVee was observed.

β-Diketiminato Organolead Complexes: Structures, 207Pb NMR, and Hammett Correlations

The synthesis, structure, and spectroscopic details of a series of β-diketiminato lead(II) alkyl complexes are described. The Hammett correlation between the 207Pb NMR chemical shifts and σpara Hammett constant was examined computationally and found to be due to the paramagnetic shielding contribution, whereas the diamagnetic and spin–orbit coupling contributions remained fairly constant across this series of compounds.

High Efficiency and Robust Performance of Organo Lead Perovskite Solar Cells with Large Grain Absorbers Prepared in Ambient Air Conditions

Abstract Organo lead halide perovskite absorbers were prepared by a two-step solution-processing method under ambient air conditions. Large cuboid crystalline grains that form a porous surface in junction with an organic hole conductor enable power conversion efficiency up to 15.3%, exhibiting minimal J–V hysteresis and stable performance against light intensity change. The cell without encapsulation showed sufficiently high stability under exposure to air.

The organomercurial lyase Merb possesses unique metal-binding properties

Select bacterial strains survive in mercury-contaminated environments due to acquisition of a transferable genetic element known as the mer operon. The mer operon typically encodes for a series of proteins that includes two enzymes, MerA and MerB. The organomercurial lyase (MerB) cleaves carbon-mercury bonds of organomercurial compounds yielding ionic mercury Hg (II) and a reduced-carbon compound. The Hg (II) ion product remains bounds until it is shuttled directly to the mercuric ion reductase (MerA) to be reduced. Based on NMR spectroscopy and X-ray crystallography studies1, we have determined that Cys96, Asp99 and Cys159 of E. Coli MerB form a catalytic triad required for cleavage of the carbon-Hg bond and binding of the Hg (II) ion product. The three catalytic residues are conserved in 61 of 65 known variants of MerB and the four remaining variants retain both cysteine residues, but contain a serine in place of Asp99. Given its unique activity, we have examined the role of serine as a catalytic residue and the ability of MerB to cleave other organometals such as organotin (known substrates or inhibitors) and organolead compounds. Soaking MerB crystals with either dimethyltindibromide or trimethylleadchloride compound indicates that MerB crystals have the capacity to cleave both carbon-Sn and carbon-Pb bonds, and we have determined crystal structures of a MerB-Sn and a MerB-Pb complex. Furthermore, substitution of Ser for Asp99 (MerB D99S) in E. coli MerB alters the metal-binding specificity, as MerB D99S chelated an unknown metal during its purification. X-ray crystallography, ICP-MS and electron paramagnetic resonance (EPR) studies were performed to identify the unknown metal and the results of these studies will be presented. Given that mercury contaminated sites are often contaminated with other heavy metals, these studies indicate that other heavy metals may have important implications when using MerA and MerB in bioremediation of organomercurial compounds.

Isotope record of anthropogenic lead pollution in lake sediments of Florida, USA

We examined the anthropogenic lead (Pb) burden that accumulated in sediment of lakes in the southeastern USA during the last ~150 years. Mining, smelting, agriculture, and fossil-fuel combustion are known to have contributed to Pb pollution in lakes of other regions. Few studies, however, have examined Pb sequestered in lakes of the southeastern USA, particulary peninsular Florida, which is subject to less continental atmospheric influence than other regions of the eastern USA. We obtained sediment cores from Little Lake Jackson and Little Lake Bonnet in Highlands County, Florida and used Pb isotopes in the records to identify principal sources of Pb contamination. The sediment records showed that changes in Pb concentration and isotope ratios correspond temporally with gasoline consumption in the USA, as well as with changes in lead ores used to produce leaded gasoline. Lead concentrations in the study lakes showed temporal variations that were similar to those found in peat records from east-central Florida. Isotope trends were similar to the mean USA atmospheric Pb deposition record, and to Pb isotope records from Bermuda and Atlantic corals. We modeled the isotopic composition of the anthropogenic Pb in lake sediments and found that the overall trend is controlled by Pb that was released during leaded gasoline combustion. There is, however, additional Pb at each site that comes from sources that are not fully represented by the natural, background Pb. Lead isotope ratios and Pb/arsenic (As) ratios provide evidence that Pb deposition in lakes during the middle 1900s might have been influenced by lead arsenate applications to golf courses, a source that is often ignored in Pb isotope studies. Isotope evidence confirms, however, that following cessation of commercial lead arsenate use in the 1960s, atmospheric alkyl lead was again the primary influence on Pb in sediments of the study lakes.

Distribution of PCDD/Fs and organometallic compounds in sewage sludge of wastewater treatment plants in China

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), organotin and organolead compounds were measured in sewage sludge samples collected from 24 wastewater treatment plants from 18 cities of 13 provinces in China. Total international toxicity equivalent (I-TEQ) values were evaluated for PCDD/Fs. The total concentration of PCDD/Fs ranged from 104.0 to 1661 pg/g dry weight (d.w.) and 2.51–75.21 pg I-TEQ/g d.w., indicating that all I-TEQs were below Chinese legislation limit value regulated for land application. The concentrations ranged from 258 to 3886, 126 to 1129, and 84–2133 ng/g as Sn d.w., for tributyltin (TBT), dibutyltin (DBT), and diphenyltin (DPhT), respectively. On the other side, organolead concentrations ranged from 85 to 668 with an average of 279 ng/g as lead. High concentrations of organolead compounds in sewage sludge indicated that the environmental impact of organolead compounds remains in China.

Synthesis and characterization of some triorgano, diorgano, monoorganotin and a triorganolead heteroaromatic dithiocarbamate complexes

The reactions of benzyl-thiophen-2-ylmethyldithiocarbamate and 4-methyl-benzyl-thiophen-2-ylmethyldithiocarbamate with six organotin compounds and one organolead compound resulted in seven dithiocarbamate complexes exhibiting different structural forms. The compounds have been characterized by multinuclear NMR and IR spectral studies. X-ray crystallographic study of the compounds were made to understand the structure and bonding in these molecules. The dithiocarbamate ligands in all the organotin and organolead complexes showed anisobidentate bonding mode, however, in case of dichlorotin bis(dithiocarbamate) symmetrically bidentate mode of bonding was observed. Representative compounds [Ph3Sn{(C6H5)(CH2)}{(C4H3S)(CH2)}NCS2] 1 and [Ph3Pb{(C6H5)(CH2)} {(C4H3S)(CH2)}NCS2] 7 on pyrolysis yielded corresponding sulfides, SnS and PbS showing the usefulness of these dithiocarbamate complexes as single source precursors for the preparation of metal sulfides.

Distribution of Different Organotin and Organolead Compounds in Sediment of Suez Gulf

Organotin and organolead compounds were determined in sediments of the Suez Gulf The concentrations of Tributyltin (TBT) ranged from 0.27 to 2.77 with an average value of 1.37 µgg-1; dry wt. However, the concentrations of dibutyltin (DBT) ranged from 0.07 to 2.27 with an average value of 0.58 µgg-1; dry wt. A significant correlation was found between TBT and DBT with r = 0.82, (p = 0.05) indicating that the occurrence of DBT is mainly related to the degradation of TBT. Generally, the high concentration of TBT was attributed to shipping activity in harbours. In addition, Diphenyltin (DPhT) concentrations ranged from not detected to 2.09 with an average of 1.10 µgg-1 dry wt. Antifouling agents, industrial discharge and the influence of sewage discharge are the main sources of pollution by DPhT compounds in Suez Gulf. On the other side, organolead (OLC) concentrations ranged from 10.88 - 440.2 with an average of 168.7 ngg-1; dry wt. A significant setting of OLC recorded in sediments of Suez Gulf was mainly attributed to cars exhaust and/or spelling and direct evaporation of fuels.

Natural and anthropogenic lead in sediments of the Rotorua lakes, New Zealand

Global atmospheric sources of lead have increased more than 100-fold over the past century as a result of deforestation, coal combustion, ore smelting and leaded petroleum. Lead compounds generally accumulate in depositional areas across the globe where, due to low solubility and relative freedom from microbial degradation, the history of their inputs is preserved. In lakes there is rapid deposition and often little bioturbation of lead, resulting in an excellent depositional history of changes in both natural and anthropogenic sources. The objective of this study was to use sediments from a regionally bounded set of lakes to provide an indication of the rates of environmental inputs of lead whilst taking into account differences of trophic state and lead exposure between lakes. Intact sediment gravity cores were collected from 13 Rotorua lakes in North Island of New Zealand between March 2006 and January 2007. Cores penetrated sediments to a depth of 16–30 cm and contained volcanic tephra from the 1886 AD Tarawera eruption. The upper depth of the Tarawera tephra enabled prescription of a date for the associated depth in the core (120 years). Each core showed a sub-surface peak in lead concentration above the Tarawera tephra which was contemporaneous with the peak use of lead alkyl as a petroleum additive in New Zealand. An 8 m piston core was taken in the largest of the lakes, Lake Rotorua, in March 2007. The lake is antipodal to the pre-industrial sources of atmospheric lead but still shows increasing lead concentrations from <2 up to 3.5 μg g − 1 between the Whakatane eruption (5530 ± 60 cal. yr BP) and the Tarawera eruption. Peaks in lead concentration in Lake Rotorua are associated with volcanic tephras, but are small compared with those arising from recent anthropogenic-derived lead deposition. Our results show that diagenetic processes associated with iron, manganese and sulfate oxidation-reduction, and sulfide precipitation, act to smooth distributions of lead from anthropogenic sources in the lake sediments. The extent of this smoothing can be related to changes in sulfate availability and reduction in sulfide driven by differences in trophic status amongst the lakes. Greatest lead mobilisation occurs in mesotrophic lakes during seasonal anoxia as iron and manganese are released to the porewater, allowing upward migration of lead towards the sediment–water interface. This lead mobilisation can only occur if sulfides are not present. The sub-surface peak in lead concentrations in lake sediments ascribed to lead alkyl in petroleum persists despite the diagenetic processes acting to disperse lead within the sediments and into the overlying water.

ChemInform Abstract: Palladium- and Copper-Catalyzed Homocoupling of Organolead Compounds: Synthesis of Biaryls and Diynes.

Abstract The palladium- and copper-catalyzed dimerization of aryl- and alkynyllead triacetates to form biaryls and dialkynes under mild conditions is described.

Synthesis, Structures, and Properties of Plumboles

Reactions of 1,4-dilithio-1,2,3,4-tetraphenyl-1,3-butadiene with dichlorodiphenylplumbane gave hexaphenylplumbole 1 and spirobiplumbole 2. These structures were determined by X-ray diffraction analysis. Electronic structures of 1 and 2 were discussed by the aid of NMR analysis and theoretical calculations. The compounds 1 and 2 were found to be the first fluorescent organolead compounds.

Alkyllead compounds and their environmental toxicology.

Alkyllead compounds are man-made compounds in which a carbon atom of one or more organic molecules is bound to a lead atom. Tetraethyllead and tetramethyllead are the most common alkyllead compounds that were used primarily as gasoline additives for many years. Consequently, auto emissions have accounted for a major part of lead environmental pollution. Alkyllead compounds can readily enter living organisms as they are well absorbed via all major routes of entry. Because of their lipid solubility, the alkylleads can also readily cross the blood-brain barrier. The toxicokinetic information on organic lead can be used as biomarkers of exposure for monitoring exposed individuals. The organic alkyllead compounds are more toxic than the inorganic forms of lead. Neurotoxicity is the predominant effect of lead (both for organic and inorganic forms), although lead affects almost every organ of the body. The use of alkyllead compounds has declined over the last 20 years, due to the worldwide effort to eliminate the use of leaded gasoline. This achievement can be viewed as a great accomplishment of public health preventive measures.

Interactions of Diorganolead(IV) with 3-(2-Thienyl)-2-sulfanylpropenoic Acid and/or Thiamine: Chemical and in Vitro and in Vivo Toxicological Results

The reactions of PbR(2)(OAc)(2) (R = Me, Ph) with 3-(2-thienyl)-2-sulfanylpropenoic acid (H(2)tspa) in methanol or ethanol afforded complexes [PbR(2)(tspa)] that electrospray ionization-mass spectrometry (ESI-MS) and IR data suggest are polymeric. X-ray studies showed that [PbPh(2)(tspa)(dmso)] x dmso, crystallized from a solution of [PbPh(2)(tspa)] in dmso, is dimeric, and that [HQ](2)[PbPh(2)(tspa)(2)] (Q = diisopropylamine), obtained after removal of [PbPh(2)(tspa)] from a reaction including Q, contains the monomeric anion [PbPh(2)(tspa)(2)](2-). In the solid state the lead atoms are O,S-chelated by the tspa(2-) ligands in all these products, and in the latter two have distorted octahedral coordination environments. NMR data suggest that tspa(2-) remains coordinated to PbR(2)(2+) in solution in dmso. Neither thiamine nor thiamine diphosphate reacted with PbMe(2)(NO(3))(2) in D(2)O. Prior addition of H(2)tspa protected LLC-PK1 renal proximal tubule cells against PbMe(2)(NO(3))(2); thiamine had no statistically significant effect by itself, but greatly potentiated the action of H(2)tspa. Administration of either H(2)tspa or thiamine to male albino Sprague-Dawley rats dosed 30 min previously with PbMe(2)(NO(3))(2) was associated with reduced inhibition of delta-ALAD by the organolead compound, and with lower lead levels in kidney and brain, but joint administration of both H(2)tspa and thiamine only lowered lead concentration in the kidney.

Development of a methodology for the simultaneous determination of inorganic and organolead compounds using supercritical fluid extraction followed by gas chromatography–mass spectrometry and its application to environmental matrices

A method for the extraction of triethyl lead (TEL +), trimethyl lead (TML +), and Pb 2+ from sand was developed using supercritical modified CO 2–CH 3OH extraction and in situ complexation with sodium diethyldithiocarbamate (NaDDTC) using a 2 5 factorial exploratory design is described. The screened variables were (i) pressure (69–193 bar), (ii) temperature (40–150 °C), (iii) ligand amount (0–100 mg), (iv) methanol volume (0.0–0.5 mL) and (v) static time (0–45 min). The optimum extraction conditions found were as follow: pressure, 193 bar; temperature, 40 °C; amount of NaDDTC, 100 mg; methanol volume, 0.5 mL; static time 45 min; and CO 2 flow rate, 1 mL min −1. Under these conditions the following recoveries were obtained (TML + 97 ± 2%, TEL + 70 ± 5%, and Pb 2+ 100 ± 4%). The presence of NaDDTC is not necessary for the extraction of TML + and TEL +, but it is a very significative parameter for Pb 2+. A second experimental design 2 2 + star for temperature and pressure was realized, but the results were not better than those of the first model. SFE extract derivatization was achieved with pentylmagnesium bromide, and target analyte determination was carried out by gas chromatography–mass spectrometry. Detection limits in the full-scan mode were 4, 10, and 39 pg as lead for TMPeL, TEPeL and PbPe 4, respectively. The method was validated with urban dust containing TML + (CRM 605. Pb 7.9 ±1.2 μg kg −1) and river sediment containing inorganic lead (GBW08301. Pb 79.0 ± 12.0 mg kg −1) as reference materials. The proposed method was applied to lead analysis in sand collected from an oil-polluted beach in Chile.

Organoboron(III) and organolead(IV) complexes as antimicrobial and antimycobacterial agents: Synthetic, structural, and biological aspects

Phenylboron(III) and triorganolead(IV) derivatives of the types PhB(OH)(DTCZ), PhB(DTCZ)2, and Ph3Pb(DTCZ) (where DTCZ− is the anion of a S-benzyldithiocarbazate ligand) have been synthesized by the substitution reactions of phenylboronic acid and triphenyllead chloride with S-benzyldithiocarbazate. The resulting complexes have been characterized by elemental analyses, molecular weight determinations, and conductivity measurements. The mode of bonding has been established on the basis of infrared and 1H, 13C, and 11B NMR spectroscopic studies. Probable tetrahedral and trigonal bipyramidal structures for the resulting derivatives have been proposed. The X-ray powder diffraction study of the compound [PhB(OH)(L1)] was carried out in order to have an idea about the molecular symmetry of the compound. The results show that the compound belongs to the orthorhombic crystal system. In the quest for better fungicides and bactericides, the studies were conducted to assess the growth inhibiting potential of the synthesized complexes against various fungal and bacterial strains. The studies demonstrate the concentration reached levels which are sufficient to inhibit and kill the pathogens. The antimycobacterial effects of the organolead(IV) compounds were also examined. The results obtained indicated that the compounds display antimycobacterial activity.

Synthesis, characterization and crystal structures of organolead dithiolate compounds displaying transannular interactions D···Pb (D = O, S)

Treatment of Ph 2PbCl 2 with O(C 6H 4SH) 2 ( 1a), S(C 6H 4SH) 2 ( 2a) and S(C 6H 3SH) 2O ( 3a) afforded the stable organolead compounds [{O(C 6H 4S) 2}PbPh 2] ( 1b), [{S(C 6H 4S) 2}PbPh 2] ( 2b) and [{S(C 6H 3S) 2O}PbPh 2] ( 3b). X-ray structure determinations of dithiolate-diphenyl lead compounds 1b– 3b revealed that the trichalcogenated ligands are tridentate in 1b and 2b, and bidentate in 3b. The lead atom acts as an acceptor atom exhibiting weak intramolecular transannular interactions with the donor D atom, with tetrahedral distortions of 48% for 1b, 51% for 2b and 45% for 3b. The local geometry at the lead atom is described as monocapped tetrahedral. The crystal packing of title compounds is stabilized by several non-bonded interactions.

Simultaneous Determination of Trimethyl- and Triethyllead in Urban Dust by Species-specific Isotope Dilution/Gas Chromatography-Inductively Coupled Plasma Mass Spectrometry

Both (206)Pb-labeled trimethyllead (TML) and triethyllead (TEL) were synthesized from (206)Pb-enriched metallic Pb certified reference material (NIST SRM 983) and iodomethane or iodoethane through a one-process reaction in a closed system using centrifuge tubes, respectively. Organolead compounds in an urban dust reference material (BCR CRM 605) were extracted with an acetic acid/methanol (1:1) solution, which was mechanically shaken for 24 h. After adjusting the pH of the extracted solution to pH 5, the extracted organolead compounds were derivatized by tetrabutylammonium tetrabutylborate (TATB) and measured with GC-ICPMS. The analytical results of TML and TEL for BCR CRM 605 were 8.22 +/- 0.04 microg kg(-1) (mean +/- standard deviation, n = 3) and 1.12 +/- 0.06 microg kg(-1), respectively. The analytical results of TML agreed well with the certified value (7.9 +/- 1.2 microg kg(-1)).

Feasibility study for the remediation of groundwater contaminated by organolead compounds

The aim of this research was to assess the effectiveness of chemical oxidation, Advanced Oxidation Processes (AOPs) and adsorption on granular activated carbon (GAC) for the ex situ remediation of a groundwater contaminated by organolead compounds, including tetraethyl lead (TEL), triethyl lead (TREL) and diethyl lead (DEL). The groundwater of concern was collected from the site of a former tetraalkyllead producing company in Trento (Italy), and showed an average total organic lead (TOL) content about 95.1 μg/L (TEL 0.5 μg/L, TREL 86.4 μg/L, DEL 8.3 μg/L). The main target of the study was to find out which method was more effective in reducing the pollutant content. For this purpose, several laboratory tests were performed, including chemical oxidation tests with different reactants (hydrogen peroxide, modified Fenton's reagent, potassium permanganate, activated potassium persulfate, oxygen and combinations of potassium permanganate and modified Fenton's reagent), AOPs with ozone, UV radiation and hydrogen peroxide and filtration on granular activated carbon. A combination of chemical and physical treatments was also tested, with GAC filtration followed by chemical oxidation. According to the results achieved, the treatments which showed the best remediation performances were: chemical oxidation with modified Fenton's reagent, AOPs with hydrogen peroxide and ozone (perozone), AOPs with hydrogen peroxide and UV radiation, and the combined treatment with activated carbon filtration followed by chemical oxidation with perozone. All these treatments showed a 90% TOL removal, with excellent removals of both TEL and TREL, and final DEL concentrations below 5 μg/L.

On the distribution of dissolved lead in the Loire estuary and the North Biscay continental shelf, France

The dissolved lead was studied in the whole salinity gradient of the system composed of the Loire estuary and the North Biscay continental shelf. About 130 samples were collected in winter 2001 and spring 2002 during Nutrigas and Gasprod campaigns (Programme PNEC-Golfe de Gascogne, RV Thalassa) and metal measurements were conducted on board by Potentiometric Stripping Analysis. In the Loire estuary, levels of dissolved lead ranged from 0.15 to 0.24 nM and from 0.04 to 0.26 nM in winter and spring, respectively. Compared to the concentrations reported in 1987 and 1990 (0.4–1.7 nM; Boutier, B., Chiffoleau, J.F., Auger, D., Truquet, I., 1993. Influence of the Loire river on dissolved lead and cadmium concentrations in coastal waters of Brittany. Estuar. Coast. Shelf S., 36:133–143, Estuarine, Coastal and Shelf Science 36, 133–143) our study indicated much lower values. The fall in concentration in the estuary could be attributed to the stopping of activity of Octel, a big manufacturer of tetra alkyl lead. Discharge in dissolved metal to the continental shelf by the Loire river was assessed as 7.5 and 1.9 kg day − 1 for winter and spring, respectively. On the continental shelf, levels of dissolved lead varied within 0.06 and 0.27 nM in winter (0.15 ± 0.06 nM, sd = 1.96, n = 49), whereas concentrations measured in spring were in the range 0.06–0.17 nM (0.09 ± 0.03 nM, sd = 1.96, n = 60). This difference in metal concentration was related to the amounts of rainfall that have fallen over the continental shelf: estimations of inputs by this way (74 and 32 kg day − 1 in winter and spring, respectively) appeared to be significantly higher than inputs from the Loire river (7.5 and 1.9 kg day − 1 in winter and spring, respectively). The distributions of dissolved metal in the surface waters highlighted the role of suspended particular matter (SPM) for a rapid “trapping” of lead near the mouth of the estuary. The vertical distributions showed, in the stratified area, a biological transfer of lead between winter and spring from surface waters to the halocline.