Metals and metal complexes in coal

1981 ◽  
Vol 300 (1453) ◽  
pp. 51-63 ◽  
Keyword(s):  
Metal Complexes ◽  
Soxhlet Extraction ◽  
Coal Liquefaction ◽  
Coal Rank ◽  
Metallic Elements ◽  
Iron Porphyrins ◽  
Metal Compounds ◽  
Manganese Porphyrins ◽  
Metal Free ◽  
Anthracene Oil

Some of the metal compounds that occur in coal are soluble in organic solvents and are extracted in coal liquefaction processes. The material made by the extraction of coal with hydrogenated anthracene oil has been fractionated by sequential Soxhlet extraction with low-boiling solvents, and the distribution of the metallic elements in the various fractions has been determined. Extraction of Daw Mill coal (92 kg) with acidic methanol furnishes 17.8 mg of a mixture of gallium complexes of homologous porphyrins (C 27 -C 32 ). Similar metalloporphyrin concentrates are obtained from a variety of British bituminous coals, the amount detected being about 1 pg/g, but falling off as coal rank increases. Various lignites and a range of Polish coals have also been surveyed: here, iron porphyrins and (in one case) manganese porphyrins have been observed. The iron porphyrins tend to be confined to coals of lower rank : in the lignites, metal-free tetrapyrroles are also detected. The metalloporphyrins are thought to be derived from the chlorophylls and haems of the biological precursors. Indeed, it is possible that the iron porphyrins are derived directly (i.e. without demetallation-metallation) from biological and microbiological haem compounds.

Noble-metal-free electrocatalysts toward H2O2 production

2020 ◽  
Vol 8 (44) ◽  
pp. 23123-23141
Author(s):  
Kai Dong ◽  
Ying Lei ◽  
Haitao Zhao ◽  
Jie Liang ◽  
Peng Ding ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Noble Metal ◽  
Recent Progress ◽  
Single Atom ◽  
H2o2 Production ◽  
Metal Compounds ◽  
Metal Free ◽  
Carbon Based

This review summaries recent progress of noble-metal-free electrocatalysts toward H2O2 production including carbon-based materials, metal compounds, single atom catalysts and metal complexes.

scholarly journals Frustration across the periodic table: heterolytic cleavage of dihydrogen by metal complexes

2017 ◽  
Vol 375 (2101) ◽  
pp. 20170002 ◽  
Author(s):  
R. Morris Bullock ◽  
Geoffrey M. Chambers
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Molecular Complexes ◽  
Main Group ◽  
Lewis Base ◽  
Metal Compounds ◽  
Metal Catalysis ◽  
Heterolytic Cleavage ◽  
Lewis Pairs

This perspective examines frustrated Lewis pairs (FLPs) in the context of heterolytic cleavage of H 2 by transition metal complexes, with an emphasis on molecular complexes bearing an intramolecular Lewis base. FLPs have traditionally been associated with main group compounds, yet many reactions of transition metal complexes support a broader classification of FLPs that includes certain types of transition metal complexes with reactivity resembling main group-based FLPs. This article surveys transition metal complexes that heterolytically cleave H 2 , which vary in the degree that the Lewis pairs within these systems interact. Many of the examples include complexes bearing a pendant amine functioning as the base with the metal functioning as the hydride acceptor. Consideration of transition metal compounds in the context of FLPs can inspire new innovations and improvements in transition metal catalysis. This article is part of the themed issue ‘Frustrated Lewis pair chemistry’.

Electrodeposition of catalytically active polyporphyrin films of metal complexes of amino-substituted tetraphenylporphyrins

2018 ◽  
Vol 22 (12) ◽  
pp. 1047-1053 ◽  
Author(s):  
Mariya V. Tesakova ◽  
Mitar Lutovac ◽  
Vladimir I. Parfenyuk
Keyword(s):  
Metal Complexes ◽  
Quartz Crystal ◽  
Film Growth ◽  
Metal Free ◽  
Porphyrin Ligand ◽  
Catalytically Active ◽  
Microscopy Method ◽  
Scanning Electron Microscopy Method ◽  
Electron Microscopy Method ◽  
Scanning Electron

The process of electrodeposition of polyporphyrin films based on amino-substituted tetraphenylporphyrins and their metal complexes (CuT([Formula: see text]-NH[Formula: see text]Ph)P, FeClT([Formula: see text]-NH[Formula: see text]Ph)P, MnClT([Formula: see text]-NH[Formula: see text]Ph)P) has been studied by the quartz crystal microbalance method. The surfaces of the films have been characterized by the scanning electron microscopy method and the number of electrons taking part in porphyrin electropolymerization has been determined. It has been established that the most intensive film growth is observed for the metal-free porphyrin ligand. The obtained polyporphyrin films have been analyzed for the catalytic ability in oxygen electroreduction reactions.

scholarly journals RECENTES APLICAÇÕES DO ORGANOFOTOCATALISADOR 1,2,3,5-TETRAQUIS(CARBAZOL-9-IL)-4,6- DICIANOBENZENO EM TRANSFORMAÇÕES QUÍMICAS

Química Nova ◽  
2020 ◽  
Author(s):  
Lucas Pugnal ◽  
Emanuele Pissinati ◽  
Karina Quaglio ◽  
Márcio Paixão
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Chemical Transformations ◽  
Redox Potentials ◽  
Research Groups ◽  
Organic Fluorophores ◽  
Metal Free ◽  
Polypyridine Complexes ◽  
Distinguished Research

RECENT APPLICATIONS OF THE ORGANIC PHOTOCATALYST 1,2,3,5-TETRAKIS(CARBAZOL-9-YL)- 4,6-DICIANOBENZENE IN CHEMICAL TRANSFORMATIONS. Ruthenium and iridium polypyridine complexes are among the most employed photocatalysts described in literature. The broad applicability is due to the redox potentials and long half-life times of the excited state which these molecules presented. The pursuit for metal-free alternatives has been intensified in the last few years, therefore, many organic fluorophores were successfully employed as photocatalysts. Among them, 1,2,3,5-tetrakis(carbazol-9-yl)- 4,6-dicianobenzene (4CzIPN) recently drawn attention of the community, and it’s been widely employed by distinguished research groups. Recent studies have shown that this catalyst do not only present similar properties to transition metal complexes, but also, its synthesis can be accomplished more easily and less expensive when compared with the metallic photocatalysts above mentioned. Therefore, 4CzIPN constitutes a metal-free alternative to replace transition metal complexes in conventional photochemical protocols. Moreover, it’s as a powerful ally in the development of new photochemical approaches. In this work, we aim to summarize recent applications of 4CzIPN as catalyst in the emerging field of redox photocatalysis.

Diverse composites of metal-complexes and PEDOT facilitated by metal-free vapour phase polymerization

2017 ◽  
Vol 116 ◽  
pp. 101-106 ◽  
Author(s):  
Shravan S. Acharya ◽  
Christopher D. Easton ◽  
Thomas M. McCoy ◽  
Leone Spiccia ◽  
C. André Ohlin ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Vapour Phase ◽  
Metal Free

Metallkomplexe von Farbstoffen, IV [1]. Übergangsmetallverbindungen mit den Dianionen von Epindolidion und 2.8-Dimethylepindolidion als Bis(chelat)-Liganden / Metal Complexes of Dyes, IV [1]. Transition Metal Compounds of the Dianions of Epindolidione and 2.8-Dimethylepindolidione as Bis(chelate) Ligands

1993 ◽  
Vol 48 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Christoph Schmidt ◽  
Wolfgang Beck ◽  
Christoph Schmidt ◽  
Wolfgang Beck
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Compounds ◽  
Chelate Complexes ◽  
Metal Compounds ◽  
Chelate Ligands ◽  
Polymeric Complexes

AbstractThe dianions of epindolidione and dimethylepindolidione act as bis(chelate) ligands (L) and form deep red polymeric complexes [L′ML]n (M = Ni(II), Co(II); L′ = DMF, PEt3). They react with chloro bridged complexes [(R3P)MCl2]2 (M = Pd, Pt) and [(η5-C5Me5)MCl2]2 (M = Rh, Ir) to give red bis-N,O-chelate complexes (R3P)(Cl)M-μ-L-M (Cl)(PR3) and (η5-C5H5)(Cl)M -μ-L-M(Cl)(η5-C5H5).

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