Hugo Vazquez-Lima

Benemérita Universidad Autónoma de Puebla | BUAP · Facultad de Ciencias Químicas

The synthesis and characterization of a novel hexacoordinated compound as a product of the reaction between chlorodimethylesterprotoprphyrin–Fe(III) 1 and 2–methylpiridine (2–CH 3 Py) was performed. The [bis(o–methylpyridino)(dimethylesterprotoporphyrinato)Fe(III)] chloride 2 is a compound of the family of the pinch–porphyrins, a model of peroxidas...

Soret-excited resonance Raman spectra (λex 413.1 nm) were acquired for manganese(III) and gold(III) tris(pentafluorophenyl)corrole, each as four different isotopomeric samples: natural abundance, fully pyrrole-¹⁵N-substituted, fully meso-¹³C-substituted, and fully pyrrole-¹⁵N-meso-¹³C-substituted. The spectra were modeled with density functional th...

Getting high purity glycerol at a low cost from biodiesel (methylricinoleate) production is of great economic interest. Therefore, exist several strategies for raw glycerol purification. Some involve liquid-liquid extraction steps using ether, toluene, n-butanol, cyclohexanol, aniline, or solvent mixtures to remove organic impurities from glycerol....

Mono- and dinuclear zinc(II) complexes bearing bis(thiosemicarbazone) (bTSC) ligand were employed in the cleavage of phosphoester bonds. Comparative kinetic studies combined with theory suggested that the P–O bond cleavage is much accelerated by dinuclear zinc(II) complex in the presence of base. Based on the DFT-optimized structures of the propose...

A scalar-relativistic DFT study of isoelectronic, quadruple-bonded Group 6 metalloporphyrins (M = Mo, W) and Group 7 metallocorroles (M = Tc, Re) has uncovered dramatic differences in ionization potential (IP) and electron affinity (EA) among the compounds. Thus, both the IPs and EAs of the corrole derivatives are 1 eV or more higher than those of...

Extensive DFT calculations with several exchange-correlation functionals indicate that molybdenum-dichlorido Viking helmet corroles are noninnocent with significant MoIV-corrole˙2- character. The effect is mediated by a Mo(4d)-corrole(π) orbital interaction similar to that postulated for MnCl, FeCl and FeNO corroles. The effect also appears to oper...

The construction and use of a simple 3D-model that is useful for visualizing the symmetry operations of D2-symmetry point group are presented. (C28-D2)[5,6]-fullerene and [Cu(en)2]2+ complex cation belong to this symmetry point group. The model can be built starting from low-cost or recyclable materials and the symmetry operations serve as a theore...

Two compounds [Co2(pa)2(μ1,1‐N3)2]n (1) and [Co4(pa)6(μ1,1‐N3)6] (2), (pa=picolinamide) were obtained and studied by electronic and magnetic spectroscopies. 1 is a polymer and 2 is a tetramer of mixed‐valence CoII/III. The N3⁻ anions act as bridges between cobalt ions in the μ1,1 coordination mode. UV‐Vis spectrum analysis showed the octahedral dis...

Tautomeric equilibria at room temperature were studied for three aromatic imine polyol compounds, previously reported 2‐((2‐hydroxybenzylidene)amino)‐2‐(hydroxymethyl)propane‐1,3‐diol 1 and two new compounds 2‐(((1,3‐dihydroxy‐2‐(hydroxymethyl)propan‐2‐yl)imino)methyl)benzene‐1,4‐diol 2 and 3‐(((1,3‐dihydroxy‐2‐(hydroxymethyl)propan‐2 yl)imino)meth...

Recent DFT calculations have suggested that iron nitrosyl triarylcorrole complexes have substantial {FeNO}7-corrole•2- character. With this formulation, reduction of Fe(C)(NO) complexes, where C = triarylcorrole, should be centered on the corrole macrocycle rather than on the {FeNO}7 moiety. To verify this proposition, visible and infrared spectroe...

In the present manuscript, we report the kinetic and spectroscopic analysis of six new pinch-porphyrins: protoporphyrin-picpenta 1, mesoporphyrin-picpenta 2, deuteroporphyrin-picpenta 3, protoporphyrin-picocta 4, mesoporphyrin-picocta 5, and deuteroporphyrin-picocta 6. The Michaelis–Menten enzymatic pathway and the guaiacol test confirmed the abili...

The conformational behavior of host molecular systems is intimately related to their performance, both as molecular containers and as interfaces in biological environments. Thus, it is of great importance to carry out rational analyses to understand this behavior. In the present study we established a systematic feedback methodology by correlating...

A combination of quantum chemical calculations and synthetic studies was used to address the possibility of very high (>6) valence states of transition metals in porphyrin‐type complexes. With corrole as a supporting ligand, DFT calculations ruled out Re(VII) and Ir(VII) dioxo complexes as stable species. Attempted rhenium insertion into benzocarba...

A series of metal-metal bonded osmium corrole dimers, {Os[TpXPC]} 2 , were synthesized in reasonably good yields (35-46%) via the interaction of the corresponding free-base meso-tris(p-X-phenyl)corroles (H 3 [TpXPC], X = CF 3 , H, CH 3 , and OCH 3 ), Os 3 (CO) 12 , and potassium carbonate in 1,2,4-trichlorobenzene under an inert atmosphere at 180 °...

Using different spectroscopic techniques and computational calculations, we describe the structural and electromagnetic relationship that causes many interesting phenomena within a novel coordination compound with mixed valence manganese (II, III and IV) in its crystal and powder state. The novel compound [MnII MnIII MnIV(HL)2(H2L)2(H2O)4](NO3)2(H2...

Relativistic and nonrelativistic density functional theory calculations were used to investigate rare or nonexistent ruthenium and osmium analogues of nitrosylhemes. Strong ligand field effects and, to a lesser degree, relativistic effects were found to destabilize {RuNO}7 porphyrins relative to their {FeNO}7 analogues. Substantially stronger relat...

Halterman corroles have been synthesized for the first time from pyrrole and Halterman's aldehyde via Gryko's "water-methanol method". These were derivatized to the corresponding copper complexes and subsequently to the β-octabromo complexes. Electronic circular dichroism spectra were recorded for the enantiopure copper complexes, affording the fir...

The high versatility of allyl groups at the dendrimer periphery makes it important to improve the methodologies to obtain them. Fréchet-type poly(aryl ether) first and second generation dendrimers bearing a conjugated phloroglucinol core with 6 or 12 peripheral allyl groups have been synthesized by convergent and divergent approaches. By the diverg...

An inherently chiral metallocorrole has been resolved for the first time by means of HPLC on a chiral stationary phase. For the compound in question, a homoleptic tungsten biscorrole, the absolute configurations of the enantiomers were assigned using online HPLC-ECD measurements in conjunction with time-dependent CAM-B3LYP calculations, which provi...

The homoleptic sandwich compounds - Mo and W biscorroles - have afforded a novel platform for experimental studies of relativistic effects. A 200 mV difference in reduction potential and a remarkable 130 nm shift of a near-IR spectral feature have been identified as manifestations of relativistic effects on the properties of these complexes.

Given the many applications of ruthenium porphyrins, the rarity of ruthenium corroles and the underdeveloped state of their chemistry are clearly indicative of an area ripe for significant breakthroughs. The tendency of ruthenium corroles to form unreactive metal-metal-bonded dimers has been recognized as a key impediment in this area. Herein, by e...

Single-crystal X-ray analysis of the ?-heptakis(trifluoromethyl)-meso-tetrakis(p-fluorophenyl)porphyrin, H2 [(CF3 )7 TpFPP], has revealed the first example of a stable cis tautomer of a free-base porphyrin, the long-postulated intermediate of porphyrin tautomerism. The stability of the unique molecule appears to reflect a dual origin: a strongly sa...

Single-crystal X-ray analysis of the β-heptakis(trifluoromethyl)-meso-tetrakis(p-fluorophenyl)porphyrin, H2[(CF3)7TpFPP], has revealed the first example of a stable cis tautomer of a free-base porphyrin, the long-postulated intermediate of porphyrin tautomerism. The stability of the unique molecule appears to reflect a dual origin: a strongly saddl...

The structural, electronic, magnetic and theoretical study of the complex [Co3(HL)2(μ-AcO)2(AcO)2], 1, (HL is the dianion obtained by deprotonation of N,N’-bis(salicylidene)-2-hydroxy-1,3-propanediamine and AcO is acetate) shows that 1 crystallizes with two independent molecules in the asymmetric unit. Each molecule is a trinuclear complex. Both mo...

The first 99Tc corroles have been synthesized and fully characterized. A single-crystal X-ray structure of a 99TcO triarylcorrole revealed nearly identical geometry parameters as the corresponding ReO structure. A significant spectral shift between the Soret maxima of TcO (410-413 nm) and ReO (438-441 nm) corroles was observed and, based on two-com...

Presented herein is a first DFT survey of metallocorrole (M = Mn, Fe, Co) adducts of CO, NO, NO(-), and HNO. Bound states with relatively short M-N(O) distances <1.9 Å are predicted for both [M(Cor)(NO)](-) and [M(Cor)(HNO)] derivatives for all three metals. The calculations also confirm the existence of moderately stable charge-neutral CoCO corrol...

For well over 20 years, μ-oxo-diiron corroles, first reported by Vogel and co-workers in the form of μ-oxo-bis[(octaethylcorrolato)iron] (Mössbauer δ 0.02 mm s(-1) , ΔEQ 2.35 mm s(-1) ), have been thought of as comprising a pair antiferromagnetically coupled low-spin Fe(IV) centers. The remarkable stability of these complexes, which can be handled...

The oxidative metalation method, involving the interaction of free-base meso-triarylcorroles and W(CO) 6 in re-fluxing decalin, led to a set of three tungsten(VI) biscorroles, the first homoleptic sandwich compounds involving corroles. Single-crystal X-ray structures of two of the complexes revealed square-antiprismatic coordination and strongly do...

The first 99Tc corroles have been synthesized and fully characterized. A single-crystal X-ray structure of a 99TcO triarylcorrole revealed nearly identical geometry parameters as the corresponding ReO structure. A significant spectral shift between the Soret maxima of TcO (410–413 nm) and ReO (438–441 nm) corroles was observed and, based on two-com...

The first FeNO octabromocorroles have been synthesized including four β-octabromo-meso-tris(p-X-phenyl)corrole derivatives Fe[Br8TpXPC](NO) (X = CF3, H, CH3, OCH3) and the β-octabromo-meso-tris(pentafluorophenyl)corrole complex, Fe[Br8TPFPC](NO). The last complex, which proved amenable to single-crystal X-ray structure determination, exhibits the g...

In contrast to noninnocent copper corroles and essentially innocent gold corroles, silver corroles appear to be poised on a knife-edge between the two electronic-structural descriptions. The summit trail of Mount Sir Alexander, a peak of the Canadian Rockies described by mountaineer Chris Goulet as a knife-edge that only a mouse can walk on, provid...

Interaction of 3,4-diiodopyrrole with 4-trifluoromethylbenzaldeyde under carefully optimized, Lindsey-type conditions at -10 °C has led to the synthesis of the first β-octaiodoporphyrin, H2[I8TpCF3PP]. The free ligand readily yielded Ni, Cu, and Zn complexes, which all proved amenable to single-crystal X-ray structure analyses. The zinc complex Zn[...

A silver β-octabromo-meso-triarylcorrole has been found to exhibit a strongly saddled geometry, providing the first instance of a strongly saddled corrole complex involving a metal other than copper. The Soret maxima of the Ag octabromocorroles also redshift markedly in response to increasingly electron-donating para substituents on the meso-aryl g...

Multiple lines of evidence, including electronic absorption spectroscopy, infrared spectroscopy, and broken-symmetry DFT calculations, indicate that the well-known FeNO corroles, long assumed to be {FeNO}6 complexes, are in fact better described as {FeNO}7-(corrole˙2−).

A series of tris(pentafluorophenyl)corrole (TPFC) tin(IV) and tin(II) complexes were prepared and studied by various characterization techniques including (1)H, (19)F, and (119)Sn NMR and UV-vis spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. The unusual 4-coordinate, monomeric, divalent tin(II) complex [(TPFC)Sn(II)](-) (2a)...

Platinum has been inserted into corroles for the first time and three oxidized Pt(IV)(corrole˙(2-))ArAr' complexes have been structurally characterized. The Soret maxima of these complexes exhibit an unusually strong dependence on the meso-aryl substituents on the corrole, indicating aryl → corrole˙(2-) charge transfer character in these transition...

Studies of the kinetics of polymerization of ε-caprolactone (CL) by salen-aluminum catalysts comprising ligands with similar steric profiles but different electron donating characteristics (R = OMe, Br, or NO2) were performed using high initial monomer concentrations (2 M < [CL]0 < 2.6 M) in toluene-d8 at temperatures ranging from 20 to 90 °C. Satu...

Six complexes, mimics of T1 Cu active site, were studied under the density functional theory framework and their redox potentials were theoretically estimated with an average error of 0.095 V. Among different functionals, the hybrid functional PBE0 gave the best results to reproduce geometric parameters and to estimate redox potentials. The use of...

A model of the three-coordinated T1 Cu site from Trametes versicolor was considered to evaluate the effect on redox potential of geometrical distortions in the copper coordination sphere. Systematic modifications of geometrical parameters (distances and angles) of the coordination sphere of the T1 Cu site were carried out within a density functiona...

Simplified models (model A: [(PhNCH2CH2)3N]Mo; model B: [(PhNCH2CH2)3N]Mo–N2) based on triamidoamine complexes were proposed to evaluate the electrostatic/orbital effects of the phenyl rings on complexation and reduction of N2. The effect of systematic synchronized rotations (from 0° to 90°) of phenyl dihedral angles on the charge and/or orbital co...

The disubstituted calix[4]arene derivative 5,11, 17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-bis(2-pyridylmethoxy)calix[4]arene 2, which crystallises in the monoclinic space group P2(1/n), was functionalised in the phenolic O-H groups with (tert-butoxycarbonyl)methoxy groups. The yield of the isolated cone and partial-cone conformers of tetrasubst...