69 research outputs found
Whereâs the Spin? A DFT Study of Mixed-Valence Cyanide-Bridged Ruthenium Polypyridines
This article discusses the use of density functional theory (DFT) calculations in classifying and characterizing bimetallic ruthenium mixed-valence systems in terms of their electronic localization/ delocalization degree. A standard B3LYP/LanL2DZ methodology including integral equation formalism-polarizable continuum model (IEF-PCM) solvent model is evaluated for a set of 16 nonsymmetric mixed-valence cyanide-bridged ruthenium polypyridines. This procedure reproduces well the features of the observed electronic and vibrational spectra, with better agreement for the more delocalized systems, and therefore provides an appropriate description of the electronic structures. Computed spin densities support class II or class III Robin-Day assignments and allow to quantify the electronic delocalization degree. The applied methodology yields good results due to the nature of the systems explored, which display a strong electronic coupling promoted by the cyanide-bridge and a lack of strong specific solvation effects. This procedure is not only useful in the study of ground state mixed-valence systems, but also provides a powerful insight into photoinduced mixed-valence excited states of related complexes.Fil: Pieslinger, German Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de QuĂmica InorgĂĄnica, AnalĂtica y QuĂmica FĂsica; ArgentinaFil: Cadranel, Alejandro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de QuĂmica InorgĂĄnica, AnalĂtica y QuĂmica FĂsica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; Argentina. Universitat Erlangen Nuremberg; AlemaniaFil: Baraldo Victorica, Luis Mario. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de QuĂmica InorgĂĄnica, AnalĂtica y QuĂmica FĂsica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; Argentin
The ExcitedâState CreutzâTaube Ion
The excited-state version of the CreutzâTaube ion was prepared via visible light excitation of [(NH3)5RuII(ÎŒ-pz)RuII(NH3)5]4+. The resulting excited state is a mixed valence {RuIIIâÎŽ(ÎŒ-pzâ
â)RuII+ÎŽ} transient species, which was characterized using femtosecond transient absorption spectroscopy with vis-NIR detection. Very intense photoinduced intervalence charge transfers were observed at 7500 cmâ1, revealing an excited-state electronic coupling element HDA=3750 cmâ1. DFT calculations confirm a strongly delocalized excited state. A notable consequence of strong electron delocalization is the nanosecond excited state lifetime, which was exploited in a proof-of-concept intermolecular electron transfer. The excited-state CreutzâTaube ion is established as a reference, and demonstrates that electron delocalization in the excited state can be leveraged for artificial photosynthesis or other photocatalytic schemes based on electron transfer chemistry.Fil: Pieslinger, German Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas; ArgentinaFil: Ramirez Wierzbicki, Ivana Elizabeth. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Cadranel, Alejandro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; Argentin
A Strongly Coupled Biruthenium Complex as Catalyst for the Water Oxidation Reaction
The catalytic activity towards water oxidation of a strongly coupled bimetallic ruthenium complex, trans-[Ru(tpy)(bpy)(ÎŒ-CN)Ru(py)4(OH2)]3+ (RuIIRuIIOH2), where tpy=2,2âČ:6âČ,2ââ-terpyridine, bpy=2,2âČ-bipyridine and py=pyridine are presented. At pH 1 the first two oxidation reactions are centred at the aquo fragment and result in the RuIIRuIIIOH2 and RuIIRuIVO redox states as confirmed by its spectroscopy and DFT calculations. Oxidation by an additional electron is followed by an irreversible step and a catalytic wave associated with the water oxidation reaction. At pH 1 the reaction with an excess of Ce(IV) results in the generation of an stoichiometric amount of oxygen based on molar amounts of the added Ce(IV). The dominant species during the catalytic cycle is the three-electron oxidized product, RuIIIRuIVO. The reduction of the concentration of Ce(IV) monitored at 370 nm follow the rate equation, âd[Ce(IV)]/dt=kox[Ce(IV)][RuIIRuIIOH2] with a kox=82±3 Mâ1sâ1 at T=298 K. The RuIIIRuIVO species is not stable and reacts to give RuIIRuIVO.Fil: DomĂnguez, SofĂa Eugenia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: JuĂĄrez, MarĂa Virginia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Pieslinger, German Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas; ArgentinaFil: Baraldo Victorica, Luis Mario. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; Argentin
Coexistence of MLCT Excited States of Different Symmetry upon Photoexcitation of a Single Molecular Species
Photoexcitation of [Ru(tpy)(bpy)(ÎŒ-CN)Ru(py) 4 Cl] 2+ ([RuRu] 2+ ) at 387 nm results in the population of two 3 MLCT excited states of different symmetry that coexist on the nanosecond scale. Common to both states is an excited electron in a tpy-based orbital. Their configuration differs in the position of the hole. In one excited state, 3 MLCTz, the hole sits in an orbital parallel to the intermetallic axis allowing for a strong metal-metal electronic interaction. As a result, 3 MLCTz is highly delocalized over both metal centers and shows an intense photoinduced intervalence charge transfer (PIIVCT) NIR signature. In the other excited state, 3 MLCTxy, the hole is localized in an orbital perpendicular to the intermetallic axis and hence, significant intermetallic coupling is absent. This state shows no PIIVCT in the NIR and its spectrum is very similar to the one observed for the monometallic [Ru(tpy)(bpy)(CN)] + reference. Both 3 MLCT excited states have nanosecond lifetimes. The intervening energy barrier for a hole reconfiguration between the two different 3 MLCT excited states offers the opportunity to exploit wave functions of different symmetry before either the interconversion between them or the decay to the ground state is operative.Fil: Oviedo, Paola Soledad. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Pieslinger, German Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Baraldo Victorica, Luis Mario. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Cadranel, Alejandro. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; Argentina. Universitat Erlangen-Nuremberg; AlemaniaFil: Guldi, Dirk M.. Universitat Erlangen-Nuremberg; Alemani
The ExcitedâState CreutzâTaube Ion
Abstract
The excitedâstate version of the CreutzâTaube ion was prepared via visible light excitation of [(NH3)5RuII(ÎŒâpz)RuII(NH3)5]4+. The resulting excited state is a mixed valence {RuIIIâÎŽ(ÎŒâpzâ
â)RuII+ÎŽ} transient species, which was characterized using femtosecond transient absorption spectroscopy with visâNIR detection. Very intense photoinduced intervalence charge transfers were observed at 7500â
cmâ1, revealing an excitedâstate electronic coupling element HDA=3750â
cmâ1. DFT calculations confirm a strongly delocalized excited state. A notable consequence of strong electron delocalization is the nanosecond excited state lifetime, which was exploited in a proofâofâconcept intermolecular electron transfer. The excitedâstate CreutzâTaube ion is established as a reference, and demonstrates that electron delocalization in the excited state can be leveraged for artificial photosynthesis or other photocatalytic schemes based on electron transfer chemistry
El tamaño importa: influencia de funcionales y bases en propiedades electrĂłnicas de polipiridinas de rutenio calculadas por teorĂa del funcional de la densidad
Durante las Ășltimas cuatro dĂ©cadas, se han desarrollado numerosas estrategias computacionales para la simulaciĂłn de espectros electrĂłnicos. En particular, las propiedades electrĂłnicas de los complejos de metales de transiciĂłn han sido de gran interĂ©s debido a la relevancia quĂmica de estos en diversos campos, desde la medicina hasta el diseño de materiales. Bajo esta perspectiva, los mĂ©todos quĂmico-cuĂĄnticos presentan numerosas ventajas y han ayudado notablemente a asignar espectros experimentales. Sin embargo, las herramientas disponibles a menudo demandan mucho tiempo de cĂĄlculo y, en general, requieren una elecciĂłn cuidadosa de los parĂĄmetros computacionales.[1,2] En este trabajo, evaluamos la performance de dos populares funcionales (B3LYP y PBE0) combinados con distintas bases (LanL2DZ, SDD, 6-31G**, def2-SVP, def2-TZVP) en el cĂĄlculo de las propiedades electrĂłnicas de la familia de polipiridinas de rutenio: trans-[RuL4(CN)2] con L = piridina, 4-metoxipiridina y 4-dimetilaminopiridina, utilizando mĂ©todos basados en la teorĂa funcional de la densidad (DFT).Para cada combinaciĂłn de funcional y base, se optimizaron las geometrĂas a partir de las estructuras de RX. Una vez confirmado que se trataban de mĂnimos locales, se utilizaron las estructuras resultantes para calcular la espectroscopĂa electrĂłnica de cada complejo.Los parĂĄmetros estructurales obtenidos a travĂ©s de cada mĂ©todo resultaron muy similares, por lo que no se justifica el uso de bases muy completas a la hora de optimizar este tipo de sistemas. Respecto a la espectroscopia, cualquiera sea la base, PBE0 tiende a sobreestimar la energĂa de las transiciones tanto respecto a B3LYP como a los resultados experimentales. Dentro de un mismo funcional, el cambio de base no muestra una clara tendencia. Sorprendentemente, B3LYP/LanL2DZ presentĂł el mejor compromiso entre precisiĂłn y costo computacional por mĂĄs que incluya la base mĂĄs pequeña entre las exploradas. Este nivel de teorĂa parece ser el mĂ©todo ganador para analizar la espectroscopĂa de esta clase de complejos.Fil: Cavalieri, Juan Pablo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Baraldo, Luis M.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Pieslinger, German Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas; ArgentinaXXII Congreso Argentino de FisicoquĂmica y QuĂmica InorgĂĄnicaArgentinaUniversidad Nacional de la Plata. Facultad de IngenierĂaAsociaciĂłn Argentina de Investigaciones FisicoquĂmica
A Hole Delocalization Strategy: Photoinduced Mixed-Valence MLCT States Featuring Extended Lifetimes
Bimetallic trans-[RuII(tpm)(bpy)(ÎŒNC)RuII(L)4(CN)]2+, where bpy is 2,2âČ-bipyridine, tpm is tris(1-pyrazolyl)methane and L = 4-methoxypyridine (MeOpy) or pyridine (py), was examined using ultrafast vis-NIR transient absorption spectroscopy. Of great relevance are the longest-lived excited states in the form of strongly coupled photoinduced mixed-valence systems, which exhibit intense photoinduced absorptions in the NIR and are freely tunable by the judicious choice of the coordination spheres of the metallic ions. Using the latter strategy, we succeeded in tailoring the excited state lifetimes of bimetallic complexes and, in turn, achieving significantly longer values relative to related monometallic complexes. Notable is the success in extending the lifetimes, when considering the higher density of vibrational states, as they are expected to facilitate nonradiative ground-state recovery.Fil: Aramburu Troselj, Bruno MartĂn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Oviedo, Paola Soledad. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Pieslinger, German Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Instituto de QuĂmica y FĂsico-QuĂmica BiolĂłgicas; ArgentinaFil: Hodak, Jose Hector. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Baraldo Victorica, Luis Mario. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Guldi, Dirk M.. Universitat Erlangen-Nuremberg; AlemaniaFil: Cadranel, Alejandro. Universitat Erlangen-Nuremberg; Alemania. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; Argentin
Down-regulation of the myo-inositol oxygenase gene family has no effect on cell wall composition in Arabidopsis
The enzyme myo-inositol oxygenase (MIOX; E.C. 1.13.99.1) catalyzes the ring-opening four-electron oxidation of myo-inositol into glucuronic acid, which is subsequently activated to UDP-glucuronic acid (UDP-GlcA) and serves as a precursor for plant cell wall polysaccharides. Starting from single T-DNA insertion lines in different MIOX-genes a quadruple knockdown (miox1/2/4/5-mutant) was obtained by crossing, which exhibits greater than 90% down-regulation of all four functional MIOX genes. Miox1/2/4/5-mutant shows no visible phenotype and produces viable pollen. The alternative pathway to UDP-glucuronic acid via UDP-glucose is upregulated in the miox1/2/4/5-mutant as a compensatory mechanism. Miox1/2/4/5-mutant is impaired in the utilization of myo-inositol for seedling growth. The incorporation of myo-inositol derived sugars into cell walls is strongly (>90%) inhibited. Instead, myo-inositol and metabolites produced from myo-inositol such as galactinol accumulate in the miox1/2/4/5-mutant. The increase in galactinol and raffinose family oligosaccharides does not enhance stress tolerance. The ascorbic acid levels are the same in mutant and wild type plants
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Diphenylamine-substituted osmanaphthalyne complexes: structural, bonding, and redox properties of unusual donorâbridgeâacceptor systems
Diarylamine-substituted osmanaphthalyne complexes
that feature two redox centers linked by the rigid
skeleton of the metallacycle (C^C+), specifically,
[OsCl2(PPh3)2{(C^C+)NAr2}][BF4
] (Ar=Ph (1 a), p-MeOPh (1 b))
and their open-ring precursors [OsHCl2(PPh3)2{(CC(PPh3
+)=
CHPh)NR2}][BF4
] (Ar=Ph (2 a), p-MeOPh (2 b)), were successfully
synthesized and characterized by 1
H, 13C, and 31P NMR
spectroscopy, ESI-MS, and elemental analysis. The solid-state
molecular structures of complexes 1 a and 2 a were ascertained
by single-crystal X-ray diffraction. The OsC bond
length in both complexes 1 a and 2 a fell within the range
reported for similar osmanaphthalynes and osmium carbyne
complexes, respectively. The structural parameters determined
for complex 1 a, which were successfully reproduced
by theoretical calculations, point to a p-delocalized metallacycle
structure. The purple color of compounds 1 a and b
was explained by the diarylamine!Os(metallacycle) chargetransfer
absorption in the visible region. The neutral, oneelectron-oxidized
and one-electron-reduced states of compounds 1 a, b, and a reference complex that lacked the diarylamine substituent, [OsCl2(PPh3)2{(C^C+)}][BF4] (1â), were investigated by cyclic and square-wave voltammetry, UV/Vis/NIR spectroelectrochemistry, and DFT calculations. The spin
density in singly oxidized complexes [1 a]+ and [1 b]+ predominantly resided on the aminyl segment, with osmium involvement controlled by the diphenylamine substitution.
Spin density in stable, singly-reduced [1â] was distributed
mainly over the osmanaphthalyne metallacycle
Character and Evolution of Ore Mineralisation in the Te-Rich EnÄsen Au-Cu Deposit, Central Sweden
The EnĂ„sen gold deposit is located in GĂ€vleborg county in central Sweden. Mining operations at EnĂ„sen took place from 1984 to 1991 with Au as the main target for exploitation. The deposit has been interpreted as a metamorphosed Palaeoproterozoic analogue to near-recent epithermal Au mineralisations of a high sulphidation type. Its present mineralogy, textural-structural features, and morphology have been suggested to be the result of a combination of later deformation and regional Svecokarelian metamorphism at upper amphibolite to granulite facies conditions of the original epithermal deposit and itâs hydrothermally altered host rock. The main ore body now consists of a mineralised sillimanite quartzite gneiss. The aim of the project was to characterise the ore mineralogy, petrography and its paragenesis, evaluate the potential of EnĂ„sen in terms of critical metals, and to test a hypothesis of partial ore melting.Among the most frequent ore minerals in the deposit are pyrite, chalcopyrite, pyrrhotite, bornite and tetrahedrite-tennantite, with variable but less abundant sulphides including covellite, digenite, mawsonite, stannite, arsenopyrite, cobaltite, galena, marcasite, sphalerite and pentlandite. Additionally, native gold, Se-bearing tellurobismuthite, hessite, tsumoite, pilsenite, rickardite, vulcanite, altaite, molybdenite, frohbergite, montbrayite, tellurantimony, löllingite and tellurbismuthantimony. While not an ore mineral here, rutile occurs abundantly. The ore mineral assemblages have seemingly at least partially melted. This is evidenced by failed quenching textures in the form of abundant multi-scale symplectites, potential sharp dihedral angles, localised concentrations of low melting point chalcophile elements (LMCE) + Au and Ag and arrays of multiphase sulphide/sulphosalt ± gold inclusions, as well as available mineral stability data considering that the ore assemblages have been subjected to upper amphibolite/granulite facies conditions followed by ductile and brittle deformation stages. Some ore mineral relationships have been described. Further studies would be required for a full paragenesis. The potential of EnĂ„sen type deposits in terms of critical or near critical metals and semi-metals is likely to be as biproduct extraction in a mining operation aimed at gold. The most relevant element is likely to be bismuth, followed by tellurium and antimony
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