Elisabete Alegria

Instituto Politécnico de Lisboa | ISEL · Departamento de Engenharia Química

The aquasoluble FeIII complexes [Fe(H2O)3(L1)]∙4H2O (Fe1) and [Fe(H2O)3(L2)]∙3H2O (Fe2), bearing the basic forms of 5‐chloro‐3‐(2‐(4,4‐dimethyl‐2,6‐dioxocyclohexylidene)hydrazinyl)‐2‐hydroxy‐benzenesulfonic acid (H3L1) and 3‐(2‐(2,4‐dioxopentan‐3‐ylidene)hydrazinyl)‐2‐hydroxy‐5‐nitrobenzenesulfonic acid (H3L2), were incorporated for the first time...

The vanadium(V) complexes bearing the aroylhydrazone Schiff base 2-hydroxy-N'-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide ligand [VO(OMe)L] (1) and [Et3NH][VO2L] (2) were synthesized, characterized and supported on porous MIL-100(Fe) forming the 1@MIL-100(Fe) and 2@MIL-100(Fe) composites. The outcome of such immobilizations was assessed by...

Plasmonic phenomena and materials have been extensively investigated for a long time and gained popularity in the last few years, finding in the design of the biosensors platforms promising applications offering devices with excellent performances. Hybrid systems composed of graphene, or other 2D materials, and plasmonic metal nanostructures presen...

The new copper(II) complexes [Cu(μ-1κO:2κONN′-HL1)(μ-1κO:2κO′-NO3)]2.[Cu(μ-1κO:2κONN′-HL1)(CH3OH)]2(NO3)2 (1) and [Cu(κONN′-HL2)(μ-1κOO’:2κO′-NO3)]n (2), derived from the new pro-ligands H2L1 = 2-(5,6-dihydroindolo[1,2-c]quinazolin-6-yl)-5-methylphenol and H2L2 = 2-(5,6-dihydroindolo[1,2-c]quinazolin-6-yl)-4-nitrophenol, were synthesized and charac...

In SERS analysis, the specificity of molecular fingerprints is combined with potential single-molecule sensitivity so that is an attractive tool to detect molecules in trace amounts. Although several substrates have been widely used from early on, there are still some problems such as the difficulties to bind some molecules to the substrate. With t...

The aroylhydrazone Schiff bases 2-hydroxy-N’-(1-(pyrazin-2-yl)ethylidene)benzohydrazide and N,N'-bis(2-hydroxybenzylidene)oxalohydrazide, have been used to synthesize the dinuclear complexes [VO(HL¹)(µ-O)]2 (1) and [{VO(OEt)(EtOH)}2(L²)] (2)·2H2O. Complex 1 is newly synthesized and 2 was reported earlier. Structural characterization of 1 was accomp...

Solvothermal reactions between the polyaromatic group containing carboxylic acid pro-ligands 5-{(pyren-1-ylmethyl)amino}isophthalic acid (H2L1) and 5-{(anthracen-9-ylmethyl)amino}isophthalic acid (H2L2) with Zn(NO3)2·6H2O led to the formation of the new 1D coordination polymer [Zn(L1)(NMF)]n (1) and four other coordination polymers, [Zn(L1)(DMF)]n...

Aiming to develop a nanoparticle-based optical biosensor using gold nanoparticles (AuNPs) synthesized using green methods and supported by carbon-based nanomaterials, we studied the role of carbon derivatives in promoting AuNPs localized surface plasmon resonance (LSPR), as well as their morphology, dispersion, and stability. Carbon derivatives are...

The neutral trichloro[hydrotris(1-pyrazolyl)methane]vanadium(III) [VCl3(Tpm)] (Tpm = HC(pz)3; pz = pyrazolyl) C-scorpionate complex was immobilized on amine-functionalized mesoporous silica (aptesSBA-15) via an impregnation method forming the [VCl3(Tpm)]@aptesSBA-15 composite. The heterogenization of the vanadium compound was confirmed by several c...

Post-grafting methodologies were used to prepare aryl-organosulfonic acid functionalized silica nanoparticles (SO3H-aryl-SiO2NPs) as highly active heterogeneous acid catalysts for catalytic esterification of free fatty acids (FFA) and levulinic acid (LA), and aldol condensation of furfural with 3-methylfuran, well known renewable feedstocks for bio...

A tetranuclear Cu(II) cubane [Cu2(μ-1κONO’:2κOO’:3κO-HL)(μ-1κONO’:2κOO’-HL)]2‧4dmf (1) derived form (2,3-dihydroxybenzylidene)-2-hydroxybenzohydrazide (H3L) was synthesized at room temperature and characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray diffraction. The known tetranuclear Cu(II) open-cubane [Cu(HL)]4‧4E...

In this study, the mononuclear Fe(III) complex [Fe(HL)(NO3)(H2O)2]NO3 (1) derived from Nʹ-acetylpyrazine-2-carbohydrazide (H2L) was synthesized and characterized by several physicochemical methods, e.g., elemental analysis, infrared (IR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and single crystal X-ray diffraction analysis....

The new Au(III) complex [AuCl2(Tpms)] (1) and the previously reported [AuCl2(Tpm)]Cl (2), bearing the potentially tridentate ligands tris(1-pyrazolyl)methanesulfonate (SO3C(C3H3N2)3⁻, Tpms) or hydrotris(1-pyrazolyl)methane (HC(C3H3N2)3, Tpm), respectively, were synthesized in water at room temperature and characterized using NMR and IR spectroscopy...

Pd(II) and Pt(II) composites with activated carbon (AC), graphene oxide, and multiwalled carbon nanotubes were prepared by ball milling and used as catalysts for the Suzuki-Miyaura reaction, under several energy inputs (mechanical grinding, conventional heating, and microwave irradiation). The catalytic composites were characterized by ICP-MS, BET,...

The aroylhydrazone Schiff bases 2-hydroxy(2-hydroxybenzylidene)benzohydrazide (H2L1) and 2-amino(2-hydroxybenzylidene)benzohydrazide (H2L2) have been used to synthesize the new Cd(II) coordination polymer [Cd(-1ONO’:2O:3O’’-L1)(DMF)]n (1) and the dinuclear complex [Cd(1ONO’:2O-HL2)(OO’-Ac)]2·2DMF (2). Both 1 and 2 have been characterized by...

ZnO nanoparticles (ZnONPs) were successfully synthesized using bravo-de-esmolfe apple extract in aqueous medium at room temperature. ZnO microparticles, prepared with a pure apple phytochemical, quercetin (ZnOq), or without phytochemicals (ZnO) were studied for comparative purposes. The re-use of apple waste for highly efficient catalyst production...

The 1D Cu(II) coordination polymers [Cu3(L1)(NO3)4(H2O)2]n (1) and [Cu2(H2L2)(NO3)(H2O)2]n(NO3)n (2) have been synthesized using the aroylhyrazone Schiff bases N'1,N'2-bis(pyridin-2-ylmethylene)oxalohydrazide (H2L1) and N'1,N'3-bis(2-hydroxybenzylidene)malonohydrazide (H4L2), respectively. They have been characterized by elemental analysis, infrare...

Iron-containing particulate catalysts of 0.1–1 µm size were prepared by wet and ball-milling procedures from common salts and characterized by FTIR, TGA, UV-Vis, PXRD, FEG-SEM, and XPS analyses. It was found that when the wet method was used, semi-spherical magnetic nanoparticles were formed, whereas the mechanochemical method resulted in the forma...

Graphene-based materials have been extensively explored in recent years as valuable candidates as the key material for novel structures in the field, among many other applications, of sensing devices. This work reports a study about the applicability of rGO as a support for gold nanoparticles (AuNPs) prepared with an economic and eco-friendly metho...

The syntheses of the heterometallic sodium and potassium-dioxidovanadium 2D polymers, [NaVO2(1κNOO';2κO"-L)(H2O)]n(1) and [KVO2(1κNOO';2κO';3κO"-L)(EtOH)]n(2) (where the κ notation indicates the coordinating atoms of the polydentate ligand L) derived from (3,5-di-tert-butyl-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L) are reported. The polym...

Pure ZnO nanoparticles were synthesized by a sustainable precipitation method using zinc nitrate and sodium hydroxide in aqueous medium at room temperature. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible...

The new aroylhydrazone N'-(di(pyridin-2-yl)methylene)pyrazine-2-carbohydrazide (HL) species, rich in N-donor sites, has been used to synthesize Cu(II) compounds with different nuclearities, viz. the binuclear [{Cu2(-1N3,2N2O-L)(Cl)3(MeOH)] (1), the octanuclear [Cu4(-1N3,2N2O-L)2(-Cl)3(Cl)3]2 (2) and the 1D coordination polymer [Cu3(3-1N3,2...

Reactions of 3,3'-{(pyridine-2,6-dicarbonyl)bis(azanediyl)} dibenzoic acid (H2L) with copper(II) nitrate were studied and the obtained compounds [Cu2(1:2O1O2,2:3O3O4-L)(-NO3)(3-OH)(MeOH2]2•2MeOH•1DMF (1) and [Cu(-1O1:2O2,3O3:4O4-L)(DMF)]n•4n(DMF) (2) were characterized by elemental analysis, FT-IR spectroscopy, single-crystal and powder X-...

Reactions between N6O4 macrocyclic 1,4,19,22,25,40-hexaaza-10,13,31,34-tetraoxa-6,14,27,35(1,4)-tetrabenzenacyclopentacontane (L) and several copper salts (viz. trifuoromethane and toluene sulfonates, nitrate, perchlorate, benzoate, and acetate) led to the formation of dinuclear compounds [Cu2(OSO2CF3)2(DMF)2L](SO3CF3)2 (1), [Cu2(p-OSO2C6H4Me)2L(DM...

Noncovalent interactions often provide the spine of biomolecular and material structures, and can therefore play a key role in biological and catalytic processes. Selectivity in chemical reactions, particularly in catalytic processes, is often an orchestral action of various noncovalent interactions occurring in intermediates and transition states....

Intensification of chemical processes according to motto “faster, simpler, greener” is among the main concerns nowadays. One of the ways of intensification is the application of catalytic synergistic effects, when overall efficiency of a composite catalyst is much higher than a sum of the component activities. Here we report on preparation of the c...

The C-scorpionate iron(II) complexes [FeCl 2 {κ ³ -HC(pz) 3 }] (1) (pz = pyrazol-1-yl), Li[FeCl 2 {κ ³ -SO 3 C(pz) 3 }] (2) and the new [FeCl 2 {κ ³ -HOCH 2 C(pz) 3 }] (3) act as catalysts for the hydrocarboxylation of cyclohexane (with CO and H 2 O) to cyclohexanecarboxylic acid in a remarkable yield (up to 60%) and under mild conditions. The cata...

—Graphene-based materials have been extensively explored in recent years as valuable candidates as the key material for novel structures in the field, among many other applications, of sensing devices. Reduced Graphene Oxide (rGO) is a type of chemically derived graphene, with equivalent optical properties but easier to be synthetized. This wo...

This chapter concerns the use of nonconventional conditions in the functionalization of alkanes, namely light alkanes and cyclohexane, which is a precursor of adipic acid, a valuable commodity. The application of ionic liquids, supercritical carbon dioxide, and microwave irradiation as alternative approaches are discussed and compared with the use...

Bis(2-hydroxybenzylidene)isophthalohydrazide (H4L) has been used to synthesize the dinuclear [Cu2(1�NO2:2�N0O02-H2L)(NO3)2(H2O)2] (1) and the tetranuclear [Cu4(�-1�NO2:2�N0O2- H2L)2(�-NO3)2(H2O)4]�2C2H5OH (2) complexes. The solvent plays an important role in determining the ligand behaviour in the syntheses of the complexes. An ethanol-acetonitrile...

Reaction of N‐acetylpyrazine‐2‐carbohydrazide (H2L) with anhydrous Fe(II) or Fe(III) chloride in CH3CN or in MeOH leads to the mononuclear [Fe(κNN'O‐HL)Cl2] (1) or binuclear [Fe(κNN'O‐HL)Cl(μ‐OMe)]2 (2) Fe(III) complex, respectively. These complexes are characterized by elemental analysis, ESI‐MS, IR spectroscopy, single‐crystal X‐ray crystallograp...

This paper reports about a study of the local plasmonic resonance (LSPR) produced by metal nanoparticles embedded in a dielectric or semiconductor matrix. It is presented an analysis of the LSPR for different nanoparticle metals, shapes, and embedding media composition. Metals of interest for nanoparticle composition are Aluminum and Gold. Shapes o...

The effect of microwave and mechanochemical ball milling energy inputs was studied for the peroxidative oxidation (with aqueous H2O2) of cyclohexane to cyclohexanol and cyclohexanone, over CoCl2 and/or V2O5 dispersed (μm scale) catalysts. The maximum total yield of cyclohexanol and cyclohexanone of 43% after 1 h reaction at 30 °C, in acetonitrile a...

Gold nanoparticles (AuNPs) were prepared using an eco-friendly approach in a single step by reduction of HAuCl4 with polyphenols from tea extracts, which act as both reducing and capping agents. The obtained AuNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–v...

A series of derivative C-scorpionate rhenium complexes, i.e., [ReCl2{NNC(O)C6H5}(Hpz)(PPh3)2] (A) (where Hpz is pyrazole), [ReCl2{NNC(O)C6H5}(Hpz)2(PPh3)] (B), [ReClF{NNC(O)C6H5}(Hpz)2(PPh3)] (C), and their precursor [ReOCl3(PPh3)2] (D), immobilized on 3-aminopropyl-functionalized silica have been prepared and used for neat O2 oxidation of n-hexane...

For the first time, a magnetic C-scorpionate catalyst was prepared from the iron(II) complex [FeCl2{k³-HC(pz)3}] (pz = pyrazol-1-yl) and ferrite, using the sustainable mechanochemical synthetic procedure. Its catalytic activity for the cyclohexane oxidation with tert-butyl hydroperoxide (TBHP) was evaluated in different conditions, namely under mic...

The development and realization of a plasmonic structure based on the LSP interaction of metal nanoparticles with an embedding matrix of amorphous silicon is proposed. As a planned application, this structure will need to be usable as the basis for a sensor device applied in biomedical applications, after proper functionalization with selective ant...

Reaction of sodium (E/Z)-2-(2-(1-cyano-2-methoxy-2-oxoethylidene)hydrazinyl)benzene-sulfonate (NaHL) with copper(II) nitrate hydrate in the presence of imidazole (im) in methanol affords [CuL(im)(H2O)] (1). Complex 1 is characterized by IR spectroscopy and ESI-MS spectrometry, elemental and single crystal X-ray crystal structural analyses. The coor...

Cu(II) complexes in two different tautomeric forms (keto and enol) derived from the aroylhydrazone Schiff base 2-hydroxy(2-hydroxybenzylidene)benzohydrazide (H2L) have been synthesized and characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray crystallography. While the compound with the enol form of the ligand exists...

A simple and clean mechanochemical synthesis at room temperature was employed to prepare CuO-Fe2O3-CoCl2 (100 nm scale), MoO3-V2O5, CuO-CoCl2, Fe2O3-CoCl2, CuO-V2O5, Cu(CH3COO)2-V2O5, Cu(CH3COO)2-MoO3 (1–100 μm scale) 3d metal based dispersed composites with different ratios of components using simple metal salts/oxides and multiwalled carbon nanot...

The catalytic activity of the iron(II) C-scorpionate complexes [FeCl2{HC(pz)3}] 1 (pz = pyrazol-1-yl) and [FeCl2{HOCH2C(pz)3}] 2, and of their precursor FeCl2·2H2O 3, towards cyclohexane oxidation with tert-butyl hydroperoxide was evaluated and compared in different media: acetonitrile, ionic liquids (1-butyl-3-methylimidazolium hexafluorophosphate...

Treatment of trans-[Mo(NCN)2(dppe)2] with alkyl halides (RX) affords the alkylated cyanoimido-complexes trans-[Mo(NCN)(NCNR)(dppe)2]X [R = Me, X = I (1); R = Et, X = I (2); R = Pr, X = I (3); R = ⁱPr, X = I (4); R = CH2Ph, X = Br (5); R = CH2C6H4NO2-4, X = Br (6)], while its reaction with the trimethyloxonium salt [Me3O][BF4] affords trans-[Mo(NCN)...

This review concerns metal-catalyzed reactions of oxidation of alcohols to the respective products, mainly ketones and aldehydes, mostly within the period of 2010-2014. Both conventional and unconventional systems, not only with usual reagents, but also with uncommon and prospective ones, are overviewed, with recently achieved developments.

A simple and mild (room temperature) process for oxidation of o-, m- or p-xylene to the corresponding methylbenzyl alcohols, tolualdehydes and toluic acids, using H2O2 (30% aqueous solution) and the iron(II) C-scorpionate [FeCl2{κ3-HC(pz)3}] (pz = pyrazol-1-yl) catalyst is presented. Remarkably, after 5 minutes of reaction an overall oxygenates yie...

Mononuclear Cu(II) and Co(II) complexes comprising 2-methyltetrazole-saccharinate bidentate N,N-chelating ligand have been synthesized for the first time and tested as homogeneous catalysts for oxidation of secondary alcohols in a solvent-free and microwave assisted protocol using aqueous tert-butyl hydroperoxide (TBHP) as oxidant. The developed ca...

A highly-nuclear copper complex [CuII8O( t BuDea)5(H t BuDea)Cl2][CuICl2]·2H2O (1) has been prepared in a one-pot reaction of copper chloride with N-tert-butyldiethanolamine in methanol in the open air. The structure of the complex was established by single-crystal X-ray analysis. The octanuclear close-packed core of 1 belongs to the (M8(μ3-X)6(μ-X...

3d metal (Cu, Fe, Co, V) containing composite catalysts for the solvent-free microwave-assisted transformation of 1-phenylethanol to acetophenone with tert-butyl hydroperoxide (TBHP) as oxidant were prepared by ball milling. The influence of multiwalled carbon nanotubes (CNTs) and graphene oxide (GO) additives on the catalytic activity of the catal...

The five metal azolate/carboxylate (MAC) compounds [Cd(dmpzc)(DMF)(H2O)] (Cd-dmpzc), [Pd(H2dmpzc)2Cl2] (Pd-dmpzc), [Cu(Hdmpzc)2] (Cu-dmpzc), [Zn4O(dmpzc)3]·Solv (Zn-dmpzc·S), and [Co4O(dmpzc)3]·Solv (Co-dmpzc·S) were isolated by coupling 3,5-dimethyl-1H-pyrazol-4-carboxylic acid (H2dmpzc) to cadmium(II), palladium(II), copper(II), zinc(II), and cob...

The reaction of the Schiff base (3,5-di-tert-butyl-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H₃L) with a copper(II) salt of a base of a strong acid, i.e., nitrate, chloride or sulphate, yielded the mononuclear complexes [Cu(H₂L)(NO₃)(H₂O)] (1), [Cu(H₂L)Cl]·2MeOH (2) and the binuclear complex [{Cu(H₂L)}₂(µ-SO₄)]·2MeOH (3), respectively, with H₂...

Two Schiff bases derived from the condensation of 2-hydroxybenzohydrazide with 3,5-di-tert-butyl-2-hydroxybenzaldehyde (H2L1) or with 2,3-dihydroxy benzaldehyde (H2L2) were used to synthesize the Fe(III) and Co(III) complexes [Fe(L1)(HL1)] (1) and [Co(L2)(HL2)] (2), respectively. The compounds were characterized by elemental analysis, IR, ESI-MS an...

This review concerns metal-catalyzed reactions of oxidation of alcohols to the respective products, mainly ketones and aldehydes, mostly within the period of 2010–2014. Both conventional and unconventional systems, not only with usual reagents, but also with uncommon and prospective ones, are overviewed, with recently achieved developments.

The redox properties of the 1,10-phenanthroline containing Robson type symmetrical macrocyclic dicopper(II) complex [Cu2L(H2O.phen)2](ClO4)2 1 (L = μ-11,23-dimethyl-3,7,15,19-tetraazatricyclo-[19.3.1.18 19,13,21] he p t a c o s a-1(24) , 2, 7, 9, 11, 13(26), 14, 19, 21(25), 22-decaene-25,26-diolate) and of its dicopper(II) precursor [Cu2L(H2O)2](Cl...

The redox properties of the 1,10-phenanthroline containing Robson type symmetrical macrocyclic dicopper(II) complex [Cu2L(H2O.phen)2](ClO4)2 1 (L = μ-11,23-dimethyl3,7,15,19- tetraazatricyclo-[19.3.1.18 19,13,21] heptacosa-1(24),2,7,9,11,13(26), 14,19,21(25),22-decaene-25,26-diolate) and of its dicopper(II) precursor [Cu2L(H2O)2](ClO4)2 2 have been...

Coupling five, rigid or flexible, bis(pyrazolato)-based tectons with late transition metal ions allowed us the isolation of eighteen coordination polymers (CPs). As assessed by thermal analysis, all of them possess a remarkable thermal stability, their decomposition temperatures lying in the range 340-500 °C. As demonstrated by N2 adsorption measur...

Although copper based metal-organic materials as potential catalysts for hydrocarbon oxidation have been studied in last few years with diverse ligand systems, the application of tetrazole based copper-organic frameworks for the oxidation of hydrocarbons under mild oxidation conditions remains unexplored.

Two new tetranuclear copper(II) complexes [Cu4(μ4-O)(L1)Cl4] (1) and [Cu4(μ4-O)(L2)2Cl4] (2), where H2L1 is a macrocyclic ligand resulting from [2+2] condensation of 2,6-diformyl-4-methylphenol (DFF) and 1,3-bis(aminopropyl)tetramethyldisiloxane, and HL2 is a 1:2 condensation product of DFF with trimethylsilyl p-aminobenzoate, have been prepared. T...

The electrochemical properties of rhodium(III) 1-3 and iridium(III) 4-6 complexes containing bis(pyrazolyl)alkane ligands [MCp*Cl(R2C(3,5-R’2pz)2)]X (M = Rh (1) or Ir (4), R = R’ = H, X = Cl; M = Rh (2) or Ir (5), R = H, R’ = Me, X = Cl; M = Rh (3) or Ir (6), R = Me, R’ = H, X = OTf; pz = pyrazolyl; Cp* =η5-C5Me5) were investigated by cyclic voltam...

[RuCl(arene)(μ-Cl)]2 dimers were treated in a 1:2 molar ratio with sodium or thallium salts of bis- and tris(pyrazolyl)borate ligands [Na(Bp)], [Tl(Tp)], and [Tl(TpiPr, 4Br)]. Mononuclear neutral complexes [RuCl(arene)(κ2-Bp)] (1: arene=p-cymene (cym); 2: arene=hexamethylbenzene (hmb); 3: arene=benzene (bz)), [RuCl(arene)(κ2-Tp)] (4: arene=cym; 6:...

The behavior of copper(II) complexes of pentane-2,4-dione and 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, [Cu(acac)2] (1) and [Cu(HFacac)2(H2O)] (2), in ionic liquids and molecular organic solvents, was studied by spectroscopic and electrochemical techniques. The electron paramagnetic resonance characterization (EPR) showed well-resolved spectra in mo...

The reactions between 4'-phenyl-terpyridine (L) and nitrate, acetate or chloride Cu(ii) salts led to the formation of [Cu(NO3)2L] (), [Cu(OCOCH3)2L]·CH2Cl2 (·CH2Cl2) and [CuCl2L]·[Cu(Cl)(μ-Cl)L]2 (), respectively. Upon dissolving in mixtures of DMSO-MeOH or EtOH-DMF the compounds [Cu(H2O){OS(CH3)2}L](NO3)2 () and [Cu(HO)(CH3CH2OH)L](NO3) () were ob...

A series of six new mixed-ligand dinuclear Mn(ii,ii) complexes of three different hydrazone Schiff bases (H3L(1), H3L(2) and H3L(3)), derived from condensation of the aromatic acid hydrazides benzohydrazide, 2-aminobenzohydrazide or 2-hydroxybenzohydrazide, with 2,3-dihydroxy benzaldehyde, respectively, is reported. Reactions of Mn(NO3)2·4H2O with...

fac-[MBr(CO)3(pypzH)] (M = Mn, Re; pypzH = (3-(2-pyridyl)pyrazole) complexes are prepared from fac-[MBr(CO)3(NCMe)2] and pypzH. The result of their deprotonation depends on the metallic substrate: the rhenium complex affords cleanly the bimetallic compound [fac-{Re(CO)3(μ(2)-pypz)}]2 (μ(2)-pypz = μ(2)-3-(2-pyridyl-κ(1)N)pyrazolate-2κ(1)N), which wa...