Mónica Moya-Cabrera

Structural Variety of Alkali Metal Compounds Containing P−E−M (E = S, Se; M = Li, Na, K) Units Derived from Nitrogen Rich Heterocycles

The preparation of novel alkali metal chalcogenides supported by multidentate nitrogen rich ligands is reported. Treatment of the ligand precursors [H{(4,5-(P(E)Ph(2))(2)tz}] (E = S (1a), Se (1b)) with organolithium reagents or elemental sodium and potassium in tetrahydrofuran (THF) leads to the isolation of 2-7 in high yields. These compounds were characterized by elemental analysis, IR spectroscopy, mass spectrometry, solution and solid-state multinuclear NMR spectroscopy, and single crystal X-ray diffraction analysis. In the solid state, 2, 4, and 5 are dimers that contain bimetallic six-membered (M(2)N(4)) rings (M = Li, Na). In 3, the discrete monomer [Li{4,5-(P(Se)Ph(2))(2)tz}(thf)(2)] (tz = 1,2,3-triazole) contains a five-membered CPSeLiN ring which adopts an envelope conformation. The polymeric arrangement [K{4,5-(P(S)Ph(2))(2)}tz](infinity) in 6 displays different bonding modes based on the hapticity of the ligand upon binding to the potassium atom. In compounds 2-6, the presence of secondary bonding features the alkali metal chalcogen bonds.

Cyclic alumosiloxanes and alumosilicates: exemplifying the Loewenstein rule at the molecular level.

The cyclic alumosiloxane [{LAl(μ-O)(Ph(2)Si)(μ-O)}(2)] (3) and alumosilicate [{LAl(μ-O){((t)BuO)(2)Si}(μ-O)}(2)] (4) were obtained by reaction of the appropriate R(2)Si(OH)(2) precursor (R = Ph, O(t)Bu) with [{LAl(H)}(2)(μ-O)] (1), providing a nice illustration of the Loewenstein rule at work at the molecular level.

Preparation of telluro- and selenoalumoxanes under mild conditions.

Syntheses of the heavy chalcogen-containing alumoxanes [(Me)LAl(SeH)]2(μ-O) (4) and ((Me)LAl)2(μ-Te)(μ-O) (7) were accomplished by the reaction of ((Me)LAlH)2(μ-O) (2; (Me)L = HC[(CMe)N(2,4,6-Me3C6H2)]2(-)) with either red selenium or metallic tellurium. The aluminum hydrogenselenide [(Me)LAl(SeH)]2(μ-Se) (3) was also prepared from the reaction of red selenium and (Me)LAlH2 (1). All compounds were characterized by spectroscopic methods and X-ray diffraction studies. Density functional theory calculations were performed on 4 and 7.

A synthetic route to a molecular galloxane dihydroxide and its group 4 heterobimetallic compounds.

Controlled hydrolysis of (Me)LGaCl2 ((Me)L = HC[(CMe)N(2,4,6-Me3C6H2)]2(-)) (1) in the presence of a N-heterocyclic carbene, as a HCl acceptor, led to the unprecedented molecular galloxane dihydroxide [{(Me)LGa(OH)}2(μ-O)] (2) in high yield. Compound 2 was used in the assembly of the heterobimetallic galloxanes with group 4 metals [{((Me)LGa)2(μ-O)}(μ-O)2{M(NR2)2}] (M = Ti, R = Me (6); M = Zr (7), Hf (8), R = Et).

Ca[(Ph2PO)2N]2·nTHF, an α-hydroperoxidation promoter of coordinated THF molecules

Ca[(Ph2PO)2N]2·nTHF (2) was obtained by direct synthesis from tetraphenylimidodiphosphinic acid and Ca° in THF. X-ray quality single crystals of Ca2[(Ph2PO)2N]4·H2O (3) and Ca[(Ph2PO)2N]2·2C4H8O3 (4) were obtained upon crystallization of 2 under different conditions. The solid-state structure of 3 reveals a Ca2O3 core in which the two hexacoordinated calcium metals are linked together by three μ-oxygen atoms from three independent tetraphenylimidodiphosphinate ligands. Compound 4 is a monomeric octahedral complex bearing two tetraphenylimidodiphosphinate ligands in the equatorial plane and two α-hydroperoxidated THF molecules, formed in situ, in the axial positions. Compound 4 represents the first example of a metal center exhibiting this type of hydroperoxidation behavior.

X-ray and spectroscopic characterisation of novel mono- and trinuclear Fe(0) complexes derived from 1-dimethylhydrazono-4-phenylbuten-3-ones

Abstract The reaction between α,β-unsaturated derivatives of monohydrazones of 1,2-dicarbonylic compounds (namely the 1-dimethylhydrazono-4-phenylbuten-3-ones (1a–c)) and di-iron nonacarbonyl affords the novel mono- and trinuclear Fe (0) complexes 2b–c and 3a–c, respectively, with a σ-N and an η2-coordination upon the CC bond of the α,β-unsaturated system for the former compounds, which actually generate six-membered metallocycles. With the latter complexes 3a–c, the main structural features are the unexpected presence of a dinuclear iron unit displaying at one end both the σ-N and σ-O coordination and at the other an η2-coordination upon the CN double bond giving rise to an unique organometallic arrangement in the heteroatom-containing moiety and, in addition, an η2-coordination of another Fe(CO)4 fragment upon the CC bond of the α,β-unsaturated system also results. The complexes were characterised by spectroscopic methods (IR, MS, 1H and 13C NMR) and their structures were confirmed by single-crystal X-ray analysis.

Novel synthesis of new 1,2,4‐trithioles by reductive coupling of benzoyldithioacetic acid derivatives mediated by Sml2

1,2,4-trithioles 2a–e are readily obtained in good yields by dimerization of benzoyldithioacetic acid derivatives using samarium diiodide as a promotor under very mild conditions. The structures of compounds 2a–e were determined by IR, 1H, and 13C NMR spectroscopies using heteronuclear multiple bond correlation, heteronuclear multiple quantum correlation, and nuclear Overhauser enhancement spectroscopy experiments, mass spectrometry, and, in the case of 2a, the structure was confirmed by single-crystal X-ray diffraction studies.

Synthesis and characterization of the first Te(IV) organometallic complexes with azepane-1-carbodithioate

GRAPHICAL ABSTRACT ABSTRACT We report the synthesis and spectroscopic characterization of organometallic Te(IV) complexes bearing the seven-membered azepane-1-carbodithioate ligand and four different types of tellurium(IV) heterocycles; [C4H8Te{S2C-N(CH2)6}2](2),[C8H8Te{S2C-N(CH2)6}2](3),[C4H8OTe{S2C-N(CH2)6}2](4)and [C5H10Te{S2C-N(CH2)6}2](5). Compounds 2–5, obtained in a 2:1 stoichiometric ratio, are air-stable for long periods of time, but readily decompose in solution. They have been characterized by elemental analyses, IR, FAB+–MS, and multinuclear NMR (1H, 13C, and 125Te) spectroscopy. The molecular structures of 2 and 5 were established by single-crystal X-ray diffraction studies. The geometrical arrangement around the tellurium atom can be described as a distorted trigonalbipyramid or sawhorse structure, typical for tellurium atom, where the lone pair is apparently stereochemically active, occupying an equatorial position. The coordination mode for the azepane-1-carbodithioate ligands is considered as anisobidentate. Due to the orthogonal arrangement of the dithiocarbamate groups around tellurium, it is difficult for other atoms to approach and in consequence there are not intermolecular secondary interactions.

CCDC 1552675: Experimental Crystal Structure Determination

Related Article: Erandi Bernabe-Pablo, Vojtech Jancik, Diego Martinez-Otero, Joaquin Barroso-Flores, Monica Moya-Cabrera|2017|Inorg.Chem.|56|7890|doi:10.1021/acs.inorgchem.7b00634

CCDC 1552676: Experimental Crystal Structure Determination

Related Article: Erandi Bernabe-Pablo, Vojtech Jancik, Diego Martinez-Otero, Joaquin Barroso-Flores, Monica Moya-Cabrera|2017|Inorg.Chem.|56|7890|doi:10.1021/acs.inorgchem.7b00634