Francisco J. Fernández-Alvarez- Professor
- Professor (Full) at University of Zaragoza
Francisco J. Fernández-Alvarez
- Professor
- Professor (Full) at University of Zaragoza
About
69
Publications
4,582
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,126
Citations
Introduction
Current institution
Publications
Publications (69)
CO(2) as feedstock: An air- and moisture-stable iridium(III) catalyst effectively promotes the hydrosilylation of CO(2) . This reaction leads to silyl formate in a highly selective manner and proceeds efficiently under mild conditions, most likely by an outer-sphere mechanism, as suggested by theoretical calculations.
The iridium(III) complex [Ir(H)(CF3SO3)(NSiN)(coe)] (NSiN = bis(pyridine-2-yloxy)methylsilyl, coe = cyclooctene) has demonstrated to be an active catalyst for the solvent-free hydrosilylation of CO2 with 1,1,1,3,5,5,5-heptamethyltrisiloxane (HMTS) under mild reaction conditions (3 bar). The activity of this catalytic system depends on the reaction...
The rhodium(I) complexes [Rh(Cl)(COD)(R-NHC-(CH2)3Si(OiPr)3)] [COD=cyclooctadiene; R=2,6-diisopropylphenyl (1 a); n-butyl (1 b)] are effective catalyst precursors for the homogeneous hydrodechlorination of benzyl chloride using HSiEt3 as hydrogen source. This reaction is selective to the formation of toluene. However, in presence of a stoichiometri...
The complex [Ir(H)(CF3SO3)(NSiN)(coe)] (NSiN=bis(pyridine-2-yloxy)methylsilyl fac-coordinated) (1) is an effective catalyst precursor for the solvent-free synthesis of silyl carbamates from reaction of aliphatic secondary amines with CO2 and HSiMe(OSiMe3)2. The preferential formation of the silyl carbamate instead of the expected formamide or methy...
The iridium(III) complex [Ir(H)(CF3SO3)(NSiN)(coe)] (NSiN = bis(pyridine-2-yloxy)methylsilyl, coe = cyclooctene) has demonstrated to be an active catalyst for the solvent-free and selective hydrosilylation of CO2 with HSiMe(OSiMe3)2 to afford the corresponding silyl formate, namely HC(O)OSiMe(OSiMe3)2. The activity of this catalytic system depends...
The 18e saturated rhodium(III) species [Rh(H)(X)(κ²‐NSitBu2)(bipyMe2)] (NSitBu2={4‐methylpyridine‐2‐yloxy}ditertbutylsilyl; bipyMe2=4,4'‐dimethylbipyridine) (X=Cl, 1; OTf, 2) have been prepared and characterized by NMR spectroscopy and in the case of 2 it has been possible to determine its solid‐state structure by X‐ray diffraction. Complex 1 has p...
An active catalytic system for the cross-dehydrogenative coupling (CDC) of a wide range of secondary amines with silanes is reported. The iridium(III) derivatives [Ir(H)(X)(κ²-NSiDMQ)(L)] (NSiDMQ = {4,8-dimethylquinoline-2-yloxy}dimethylsilyl; L = coe, X = Cl, 2; L = coe, X = OTf, 3; L = PCy3, X = Cl, 4; L = PCy3, X = OTf, 5), which are stabilized...
![Synthesis of the complex [Re(κ²‐N,Si‐L1)(CO)4] (1).](publication/380822285/figure/fig2/AS:11431281284522772@1729266687970/Synthesis-of-the-complex-Rek-N-Si-L1CO4-1_Q320.jpg)
![Synthesis of complexes [M(Cl)(κ²‐N,Si‐L2)2] (M=Rh, 2; Ir, 3) and...](publication/380822285/figure/fig3/AS:11431281284440460@1729266688128/Synthesis-of-complexes-MClk-N-Si-L22-MRh-2-Ir-3-and_Q320.jpg)
![Synthesis of complexes [M(κ²‐Si,N‐Ln)3] (Ln=L2, L3, L4 and L5).](publication/380822285/figure/fig4/AS:11431281284456690@1729266688308/Synthesis-of-complexes-Mk-Si-N-Ln3-LnL2-L3-L4-and-L5_Q320.jpg)
![Synthesis of the complex [Co(κ²‐N,Si‐L6)3] (13).](publication/380822285/figure/fig5/AS:11431281284502946@1729266688690/Synthesis-of-the-complex-Cok-N-Si-L63-13_Q320.jpg)
The chemistry of transition‐metal (TM) complexes with monoanionic bidentate (κ²‐L,Si) silyl ligands has considerably grown in recent years. This work summarizes the advances in the chemistry of TM‐(κ²‐L,Si) complexes (L=N‐heterocycle, phosphine, N‐heterocyclic carbene, thioether, ester, silylether or tetrylene). The most common synthetic method has...
This chapter reviews the state of the art of rhodium- and iridium-catalyzed hydrosilylation reactions, demonstrating the utility of rhodium and iridium catalysts for organic synthesis. Nowadays, this field has solid and proven mechanistic foundations that allow the design, development, and optimization of new catalytic systems. As this chemistry wi...
Correction for 'Iridium-(κ2-NSi) catalyzed dehydrogenation of formic acid: effect of auxiliary ligands on the catalytic performance' by Alejandra Gomez-España et al., Dalton Trans., 2023, 52, 6722-6729, https://doi.org/10.1039/d3dt00744h.
Correction for 'Iridium-(κ2-NSi) catalyzed dehydrogenation of formic acid: effect of auxiliary ligands on the catalytic performance' by Alejandra Gomez-España et al., Dalton Trans., 2023, https://doi.org/10.1039/d3dt00744h.
The iridium(III) complexes [Ir(H)(Cl)(κ2-NSitBu2)(κ2-bipyMe2)] (2) and [Ir(H)(OTf)(κ2-NSitBu2)(κ2-bipyMe2)] (3) (NSitBu2 = {4-methylpyridine-2-yloxy}ditertbutylsilyl) have been synthesized and characterized including X-ray studies of 3. A comparative study of the catalytic activity of complexes 2, 3, [Ir(H)(OTf)(κ2-NSitBu2)(coe)] (4), and [Ir(H)(OT...
The catalytic system [Ir(CF3CO2)(κ2-NSiMe)2] [1; NSiMe = (4-methylpyridin-2-yloxy)dimethylsilyl]/B(C6F5)3 promotes the selective reduction of CO2 with tertiary silanes to the corresponding bis(silyl)acetal. Stoichiometric and catalytic studies evidenced that species [Ir(CF3COO-B(C6F5)3)(κ2-NSiMe)2] (3), [Ir(κ2-NSiMe)2][HB(C6F5)3] (4), and [Ir(HCOO-...
The reaction of [IrH(Cl)(κ2-NSitBu2)(coe)] (1) with 1 equiv of PCy3 (or PHtBu2) gives the species [IrH(Cl)(κ2-NSitBu2)(L)] (L = PCy3, 2a; PHtBu2, 2b), which reacts with 1 equiv of AgOTf to afford [IrH(OTf)(κ2-NSitBu2)(L)] (L = PCy3, 3a and PHtBu2, 3b). Complexes 2a, 2b, 3a, and 3b have been characterized by means of NMR spectroscopy and HR-MS. The...
The present research investigates the mental models about the atom of Spanish 15- to 18- years old students. A sample of 454 students was taken into account within a representative Spanish context. A specific questionnaire, validated before students solved it, where the students should draw, define and argue was designed. It has been found that mos...
Using a low loading of the iridium(III) complexes [Ir(CF3SO3)(κ2-NSiiPr)2] (1) (NSiiPr = (4-methylpyridin-2-yloxy)diisopropylsilyl) and [{Ir(κ2-NSiMe)2}2(μ-CF3SO3)2] (2) (NSiMe = (4-methylpyridin-2-yloxy)dimethylsilyl) in the presence of Et3N, it has been possible to achieve the solventless selective dehydrogenation of formic acid. The best catalyt...
Formic acid (FA) possesses a high volumetric concentration of H2 (53 g L−1). Moreover, it can be easily prepared, stored, and transported. Therefore, FA stands out as a potential liquid organic hydrogen carrier (LOHC), which allows storage and transportation of hydrogen in a safe way. The dehydrogenation to produce H2 and CO2 competes with its dehy...
The Ir-Si bond distances reported for Ir-(fac-κ3-NSiNOPy) and Ir-(fac-κ3-NSiN4MeOPy) species (NSiNOPy = bis(pyridine-2-yloxy)methylsilyl and NSiN4MeOPy = bis(4-methyl-pyridine-2-yloxy)methylsily) are in the range of 2.220-2.235 Å. These values are in the lowest limit of the Ir-Si bond distances found in the Cambridge Structural Database (CSD). To u...
Iridium(III) complexes of the general formula [Ir(X)(κ²-NSiiPr2)2] (NSiiPr2 = (4-methyl-pyridine-2-yloxy)diisopropylsilyl; X = Cl, 3; CF3SO3, 5; CF3CO2, 6) have been prepared and fully characterized, including X-ray diffraction studies and theoretical calculations. The presence of isopropyl substituents at the silicon atom favours the monomeric str...
The knowledge of the potential of transition metal-based complexes as catalysts for the reduction of CO2 has grown significantly over the last few decades. This chapter focuses on the progress made during recent years in the field of homogeneous iridium-catalyzed reduction of CO2 by using hydrogen and/or silicon hydrides as reducing agents, compari...
The iridium complex [Ir(μ-CF3SO3)(κ²-NSiMe2)2]2 (3) (NSiMe2 = {4-methylpyridine-2-yloxy}dimethylsilyl) has been prepared by reaction of [Ir(μ-Cl)(κ²-NSiMe2)2]2 (1) with two equivalents of AgCF3SO3. The solid structure of 3 evidenced its dinuclear nature, being a rare example of an iridium species with triflate groups acting as bridges. The 3-cataly...
The zwitterionic complex [Cp*IrCl{(MeIm)2CHCOO}] (1) efficiently catalyzes the selective hydrosilylation of CO2 to afford the corresponding silylformate. The best reaction performance has been achieved in acetonitrile at 348 K using HSiMe2Ph. The 1‐catalyzed reaction of pyrrolidine with CO2 and HSiMe2Ph strongly depends on the CO2 pressure. At low...
The reaction of (4-methyl-pyridine-2-iloxy)dimethylsilane (NSiMe–H, 1) with [RhCl(coe)2]2 gives the rhodium(III) complex [Rh(Cl)(κ²-NSiMe)2] (2), which reacts with a stoichiometric amount of AgCF3CO2 to afford [Rh(κ²-CF3CO2)(κ²-NSiMe)2] (3). Complexes 2 and 3 have been fully characterized by elemental analysis and NMR spectroscopy. The solid-state...
The iridium(III) complex [Ir(CF3CO2)(κ2-NSi)2] (3) (NSi = 4-methylpyridine-2-yloxydimethylsilyl) has proven to be an effective catalyst for the reduction of CO2 with HSiMe(OSiMe3)2 under mild reaction conditions. 1H NMR studies of the 3-catalyzed reactions of CO2 with HSiMe(OSiMe3)2 in C6D6 at 298 K evidenced that the selectivity of these reduction...
Reaction of [Ir(μ-Cl)(COE)2]2 (COE = cis-cyclooctene) with tris(3,5-dimethylpyrazol-1-yl)methane (MeTpm) affords complex [IrCl(κ1-N-MeTpm)(COD)] (1) (COD = 1,5-cyclooctadiene). The formation of 1 implies the transfer dehydrogenation of a COE ligand to give COD and COA (cyclooctane). A mechanistic proposal based on DFT calculations that explains thi...
This article reviews the most recent advances on the study of non-classical mechanisms for the reduction of organic substrates with hydrosilanes catalyzed by transition metals. A wide variety of catalytic cycles that go beyond the classical steps described for Ojima, Chalk-Harrod and modified Chalk-Harrod mechanisms, as representative examples, hav...
The reaction of (4-methyl-pyridin-2-iloxy)ditertbutylsilane (NSitBu-H, 1) with [IrCl(coe)2]2 affords the iridium(III) complex [Ir(H)(Cl)(κ2-NSitBu)(coe)] (2), which has been fully characterized including X-ray diffraction studies. The reaction of 2 with AgCF3SO3 leads to the formation of species [Ir(H)(CF3SO3)(κ2-NSitBu)(coe)] (3). The iridium comp...
The Cover Feature shows the formation of silylformates, bis(silyl)acetals or methoxysilanes by catalytic reduction of CO2 with hydrosilanes. In their Full Paper, F. J. Fernández‐Alvarez and L. A. Oro summarize the different catalytic systems that have shown to be efficient for the transformation of CO2 into value added chemicals using silicon‐hydri...
During the last recent years, the catalytic transformation of CO2 using silicon‐hydrides as reductants has emerged as a promising methodology that allows the selective reduction of CO2 to the formate, formaldehyde, methoxide or methane level under mild reaction conditions. Moreover, some catalysts have been employed for the formylation and/or methy...
This work describes the results from the studies on the potential of [Ir(-Cl)(cod)]2 (cod = 1,5-cyclooctadiene) as metallic precursor for the preparation of Ir(NSiN) complexes (NSiN = fac-bis-(pyridine-2-yloxy)methylsilyl). It is noteworthy that the reaction of [Ir(-Cl)(cod)]2 with bis-(pyridine-2-yloxy)methylsilane has allowed the synthesis of [...
The hydrosilylation of CO2 with different silanes such as HSiEt3, HSiMe2Ph, HSiMePh2, HSiMe(OSiMe3)2 and HSi(OSiMe3)3 in presence of catalytic ammounts of the iridium(III) complex [Ir(H)(CF3CO2)(NSiN*)(coe)] (1; NSiN* = fac-bis-(4-methylpyridine-2-yloxy); coe = cis-cyclooctene) has been comparatively studied. The activity of the hydrosilylation cat...
The number of late transition metal complexes bearing tridentate monoanionic silyl-based NSiN-type ligands has grown in the last few years. This review describes the synthetic methodologies that allow preparation of NSiN ligands precursors as well as the chemical and structural behavior of the transition metal complexes resulting from the reaction...
The iridium–NSiN species [Ir(H)(X)(NSiN)(coe)] (coe = cis-cyclooctene; NSiN = bis(pyridine-2-yloxy)methylsilyl fac-coordinated; X = Cl, (1); CF3SO3, (2)) have been proven to be effective catalyst precursors for the formation of silylphosphinecarboxylates (P{CO2SiMe3}(R)2 (R = Ph, (3a); Cy (3b))) by the reaction of CO2 with the corresponding silyl p...
A series of rhodium–NSiN complexes (NSiN=bis (pyridine-2-yloxy)methylsilyl fac-coordinated) is reported, including the solid-state structures of [Rh(H)(Cl)(NSiN)(PCy3)] (Cy=cyclohexane) and [Rh(H)(CF3SO3)(NSiN)(coe)] (coe=cis-cyclooctene). The [Rh(H)(CF3SO3)(NSiN)(coe)]-catalyzed reaction of acetophenone with silanes performed in an open system was...
The catalytic activity of various Ir-NSiN-type complexes, containing different ancillary ligands and/or modified NSiN-type ligands, as catalyst precursors for CO2-hydrosilylation has been studied. The results from these experiments evidenced that the activity and selectivity of the above mentioned catalytic systems depend on the nature of the ancil...
The copper(I) complexes [Cu(X){2,6-diisopropylphenyl–NHC–(CH2)3Si(OiPr)3}] (X=Cl (2 a); I (2 b), NHC=N-heterocyclic carbene) have been synthesized and characterized. Furthermore, the structure of 2 b has been confirmed by X-ray diffraction studies. Complex 2 a has been successfully anchored in MCM-41 to afford 2–MCM-41. The activity of both the hom...
We describe a bis‐N‐heterocyclic carbene rhodium(III) complex, featuring two trifluoroacetato ligands, that affords a variety of α‐vinylsilanes in good yields by hydrosilylation of terminal alkynes. Selectivities around 7:1 α/β‐( E ) were reached, while the β‐( Z ) product was only marginally obtained. This example sharply contrasts with the β‐( Z...
The rhodium(I) complex [Rh(Cl)(COD)(2-methoxyphenyl-NHC-(CH2)3Si(OiPr)3)] (2a) catalyzes the solvent-free homogeneous hydrosilylation of acetophenone with HSiMe(OSiMe3)2. Kinetic studies show that 2a behaves differently to the related homogeneous catalysts [Rh(Cl)(COD)(R-NHC-(CH2)3Si(OiPr)3)] (R = 2,6-diisopropylphenyl, (2b); R = 2-methoxyethyl (2c...
Breaking ties: Recent reports on iridium and ruthenium homogeneous hydrosilylation catalysis point to a heterolytic activation of SiH bonds promoted by the oxophilicity of the silicon atom and the Lewis acidity of the metal center. This unusual type of mechanism opens the door to a more widespread use of catalysts that operate by an ionic or concer...
The iridium(III) complex [Ir(H)(CF3SO3)(NSiN)(coe)] (NSiN=fac-coordinated bis(pyridine-2-yloxy)methylsilyl, coe=cyclooctene) has been proven to be an effective catalyst precursor for hydrogen production from the hydrolysis of hydrosilanes at room temperature. The reaction performance depends both on the nature of the silane and the solvent. Interes...
Catalytic CO2 hydrosilylation is a thermodynamically favored chemical process that could be potentially applied to large-scale transformations of this greenhouse gas. During the last decade, there has been an increasing number of experimental studies regarding metal-catalyzed CO2 hydrosilylation processes. The first examples of catalytic systems us...
The new rhodium(I) complexes [Rh(Cl)(COD)(R-NHC-(CH2)3Si(OiPr3)3)] (R = 2,6-diisopropylphenyl (2a); n-butyl (2b))
have been synthesised and fully characterised. The study of their application as ketone hydrosilylation catalysts
showed a clear N-substituent effect, 2a being the most active catalyst precursor. Complex 2a has been
immobilised in the m...
Recent reports on homogeneous catalytic transformation of
carbon dioxide by iridium complexes have prompted us to
review the area. Progress on new iridium catalysts for carbon
dioxide transformations should take into account the interaction
of carbon dioxide with the iridium center, which seems to
be governed by the oxidation state of iridium and t...
The β-Z selectivity in the hydrosilylation of terminal alkynes has been hitherto explained by introduction of isomerisation steps in classical mechanisms. DFT calculations and experimental observations on the system [M(I)2 {κ-C,C,O,O-(bis-NHC)}]BF4 (M=Ir (3 a), Rh (3 b); bis-NHC=methylenebis(N-2-methoxyethyl)imidazole-2-ylidene) support a new mecha...
The catalytic activation of bonds is a key step determining the outcome of the overall transformation of organic substrates. A relevant endeavor is the development of economically viable catalytic systems that efficiently convert alkanes or saturated hydrocarbons into more valuable chemicals. The focus of this chapter is on stoichiometric and catal...
The preparation of 1-(3-triisopropoxysilylpropyl)-3-(2-methoxyethyl)-imidazolium bromide or chloride salts and their reaction with [Rh(COD)(μ-OMe)]2 (COD=1,5-cyclooctadiene) to afford the corresponding [Rh(COD)(NHC)X] (X=Br, Cl; NHC=1-(3-triisopropoxysilylpropyl)-3-(2-methoxyethyl)-2-ilydene-imidazol) species is described. These new compounds were...
A synthon for a 14-electron Ir(III) species is described. The geometrical control exerted by the ligand system over the Ir-alkenyl intermediate in hydrosilylation of terminal alkynes precludes formation of the more thermodynamically stable β-(E)-vinylsilane, thus affording the β-(Z) isomer in excellent yields.
The complex OsH(2)Cl(2)(P(i)Pr(3))(2) reacts with pinacolborane, Me(2)NH-BH(3), and (t)BuNH(2)-BH(3) to give the complexes OsH(2)Cl{eta(2)-HBOC(CH(3))(2)C(CH(3))(2)OBpin}(P(i)Pr(3))(2) and OsH(2)Cl(eta(2)-HBNR(1)R(2))(P(i)Pr(3))(2) (R(1) = R(2) = Me; R(1) = H, R(2) = (t)Bu) containing monosubstituted alkoxy- and amidoborinium cations coordinated as...
The reactions of the iridium complexes IrHCl(2)(P(i)Pr(3))(2) (1) and IrCl(eta(2)-C(8)H(14))(P(i)Pr(3))(2) (2) with quinoline, 8-methylquinoline, 2-methylpyridine and benzo[h]quinoline (Hbq) have been studied. Complex 1 promotes the NH-tautomerization of quinoline and 8-methylquinoline and stabilizes the resulting NH-tautomers to afford IrHCl(2){ka...
Complexes MH2Cl2(PiPr3)2 (M = Os (1), Ru (1a)) promote the NH-tautomerization of 2-methylpyridine and stabilize the resulting NH-tautomer to afford the dihydrogen derivatives MCl2(η2-H2){κ-C-[HNC5H3Me]}(PiPr3)2 (M = Os (2), Ru (3)), containing the heterocycle coordinated by the Cα atom. In dichloromethane under reflux, complex 3 loses the coordinat...
Benzo[h]quinoline (Hbq) undergoes 1,2-hydrogen shift from the carbon at the 2-position to the nitrogen in the presence of the complexes MH2Cl2(PiPr3)2 (M = Os (1), Ru (1a)). The coordination of the undressed carbon atom of the resulting NH tautomer (HNbq) to the metal center of the osmium and ruthenium complexes gives rise to the formation of the o...
Complexes OsH2Cl2(PiPr3)2 and RuH2Cl2(PiPr3)2 promote the tautomerization of quinoline and 8-methylquinoline to NH tautomers, which lie about 44 kcal.mol-1 above the usual CH tautomers. The NH tautomers are stabilized by coordination to the metal center and by means of a Cl...HN interaction. As a consequence, the six-coordinate elongated dihydrogen...
Treatment of [Ir(μ-Cl)(COE)2]2 (1) with LiCpO gives Ir(η5-CpO)(COE)2 (2; CpO = C5H4(CH2)2OCH3, COE = cis-cyclooctene), which reacts with X2 to afford the iridium(III) derivatives [Ir(η5-CpO)X(μ-X)]2 (X = I (3), Cl (4)). Complexes 3 and 4 react with PiPr3 to yield the corresponding species Ir(η5-CpO)(PiPr3)X2 (X = I (5), Cl (6)), which by addition o...
Complex OsH2Cl2(PiPr3)2 promotes the C-H activation of 2-vinylpyridine and subsequently couples the activated substrate with a second 2-vinylpyridine and two acetylene molecules. In the absence of 2-vinylpyridine, the activated substrate is coupled with an acetylene unit to afford a 2-butadienylpyridine derivative.
The symmetric d(5) trans-bis-alkynyl complexes [Mn(dmpe)(2)(C triple bond CSiR(3))(2)] (R = Me, 1 a; Et, 1 b; Ph, 1 c) (dmpe = 1,2-bis(dimethylphosphino)ethane) have been prepared by the reaction of [Mn(dmpe)(2)Br(2)] with two equivalents of the corresponding acetylide LiC triple bond CSiR(3). The reactions of species 1 with [Cp(2)Fe][PF(6)] yield...
The theoretically characterized (DFT) C4 cumulenic species Mn(C5H4R)(dmpe)
{CCCC(SnPh3)2} was obtained by photolysis of the Csp2–Sn bond in the vinylidene complex Mn(C5H4R)(dmpe)[CC(SnPh3)–CCSnPh3], which in turn was prepared by a thermal reaction from MnC5H4R(dmpe)(C7H8) and Ph3Sn–C4–SnPh3.
Complex [Ir(mu-Cl)(COE)(2)](2) (1; COE = cis-cyclooctene) reacts with Li[C5H4(CH2)(2)N(CH3)(2)] to give Ir{eta(5)-C5H4(CH2)(2)N(CH3)(2)}(COE)(2) (2), which affords IrI2-{eta(5)-C-5,kappa-N-[C5H4(CH2)(2)N(CH3)(2)]} (3), by addition of I-2. The reaction of 3 with phenylacetylene yields Ir{eta(5)-C-5, sigma- C-a,sigma-C-b-[C5H4(CH2)(2)N(CH3)(2)C-a=CHC...
The binuclear rigid-rod complex
[{Mn(dmpe)2(CCH)}2(μ-C4
)][PF6] was spontaneously obtained from the reaction of
[Mn(dmpe)2(CCSiMe3)2][PF6
] with one equivalent of TBAF.
The reaction of the low-spin d5 complex Mn(dmpe)2(CCSiMe3)2 (1) (dmpe = 1,2-bis(dimethylphosphino)ethane) with [NBu4][Ph3F2M] (M = Si or Sn) yields the SiMe3 metathesis products Mn(dmpe)2(CCMPh3)2 (M = Si 2a, Sn 2b). When the Mn(II) species 1 was dissolved in MeOH in the presence of NaBF4, disproportionation occurred with formation of the Mn(I) pro...
Vinylation of the chloro–ethyl and dichloro zirconium complexes [Zr(CpSi2Cp)ClX] (CpSi2Cp=1,1′,2,2′-(SiMe2)2(η5-C5H3)2; X=Et, Cl) with one or two equivalents of Mg(CHCH2)Cl gave the new zirconacyclopentane [Zr(CpSi2Cp){η2-CH2(CH2)2CH2}] and (η4-butadiene)zirconium [Zr(CpSi2Cp){η4-(butadiene)}] complexes, respectively. Addition of a toluene solut...
New dicyclopentadienyl iminoacyl zirconium complexes have been prepared and characterized by NMR spectroscopy. The reaction of [Zr{SiMe2)2(η5-C5H3)2)Me2] with CNR (R 2,6-Me2C6H3, t-Bu) yields [Zr((SiMe2)2(η5-C5H3)2Me(η2-CMeNR)] (R = 2,6-Me2C6H3, t-Bu), which reacts with a stoichiometric amount of water to give the μ-oxo dimers [Zr{(SiMe2)2(η5-C5H...
Alkylation of [Zr(CpSi2Cp)Cl2] (CpSi2Cp = (η5-C5H3)2[Si(CH3)2]2 with 1 equiv of RMgCl in THF at 10 °C gave the monoalkylated complexes [Zr(CpSi2Cp)ClR] (R = Et, n-Pr, i-Pr) in 80% yield, the isopropyl complex isomerizing to the n-propyl derivative above 10 °C. Addition of a second equivalent or an excess amount of the akylating agent resulted in th...
Alkylation Of [Zr(CpSi2Cp)Cl2] (CpSi2Cp = (η5-C5H3)2[Si(CH 3)2]2 with 1 equiv of RMgCl in THF at 10 °C gave the monoalkylated complexes [Zr(CpSi2Cp)ClR] (R = Et, n-Pr, i-Pr) in 80% yield, the isopropyl complex isomerizing to the n-propyl derivative above 10 °C. Addition of a second equivalent or an excess amount of the akylating agent resulted in t...
Questions
Question (1)
I often have troubles obtaining adequate elemental analysis for iridium compounds when the ligand is triflate (CF3SO3), hydrogen and nitrogen work well but carbon is usually about 5% lower and sulfur values are random, even in samples from the same batch. Does anyone know if this is frequent? Are there any references to problems in the analysis when there is sulfur in the organometallic samples?
