Synthesis and structure of diamine bis(phenolate) complexes containing the Ti(OEt)–O–Ti(OEt) function

Reaction of diamine-bis(phenol) ligands containing a mixture of N-methyl and N,N′-dimethyl-N,N-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine, H₂L¹ and H₂L³, with [Ti(OCHMe₂)₄ in absolute ethanol under reflux without exclusion of air and moisture gives [(L¹)Ti (OEt–O–Ti(OEt)(L¹)] (1). [(L³)Ti(OEt)–O–Ti(OEt)(L³)] (2) forms when the remaining solution containing [(L³)Ti(OEt)₂] (3) (characterised by X-ray crystallography) is hydrolysed with H₂O. For the N-methyl and N,N′-dimethyl ligand mixture H₂L² and H₂L⁴, which contain tert-butyl groups on the ortho-positions of the aryl rings, [(L²)Ti(OEt)–O–Ti(OEt)(L²)] (4) forms much more slowly and [(L⁴)Ti(OEt)₂] (5) does not hydrolyse when H₂O is added. When the N-protonated ligand N,N-bis(2-hydroxy-3-methyl-5-tert-butylbenzyl)ethylenediamine, H₂L⁵, is used, rapid hydrolysis to two isomers of [(L⁵)Ti(OEt–O–Ti(OEt)(L⁵)] (6) occurs without addition of water. For N,N-bis(2-hydroxy-3,5-di-tert-butylbenzyl)ethylenediamine, H₂L⁶, hydrolysis to [(L⁶)Ti(OEt)–O–Ti(OEt)(L⁶)] (7) occurs slowly when H₂O is added. For pendant NMe₂ ligand N,N-dimethyl-N′,N′-bis(2-hydroxy-3-methyl-5-tert-butylbenzyl)ethylenediamine, H₂L⁷, the hydrolysis reaction readily gives [(L⁷)Ti(OEt)–O–Ti(OEt)(L⁷)] (8) for which an X-ray crystal structure was obtained. The ortho-tert-butyl ligand derivative H₂L⁸ formed a complex analysing as [(L⁸)Ti(OEt)–O–Ti(OEt)(L⁸)] (9) which could not be studied further due to insolubility. Pendant pyridine ligand N-(2-pyridylmethyl)-N,N-bis(2′-hydroxy-3′-methyl-5′-tert-butylbenzyl)amine, H₂L⁹, apparently forms isomers of [(L⁹)Ti(OEt)–O–Ti(OEt)(L⁹)] and possibly [{(L⁹)Ti(O)}₂] from [(L⁹)Ti(OEt)₂] (10). The ortho-tert-butyl ligand derivative H₂L¹⁰ formed [(L¹⁰)Ti(OEt)–O–Ti(OEt)(L¹⁰)] (11) for which an X-ray crystal structure was obtained.     

Oxide promoted isomerisation of an isonitrile complex,H2Os3(CO)10[CN(CH2)3Si(OEt)3]

The isomerisation of H₂Os₃(CO)₁₀[CN(CH₂)₃Si(OEt)₃] to HOs₃(CO)₁₀-[CN(H)(CH₂)₃Si(OEt)₃] is accelerated by interaction with some oxides; both complexes afford HOs₃(CO)₁₀[CN(H)(CH₂)₃Si(OEt)_3it-x(O)x] as oxide supported clusters.     

Preparation of dinitrogen complexes Mo(N2)2P4 stabilised by phosphonite PPh(OEt)2 and phosphinite PPh2(OEt) ligands

Dinitrogen complexes Mo(N₂)₂P₄1, 2 [P=PPh(OEt)₂ and PPh₂OEt] were prepared by allowing a MoCl₃(THF)₃ solution containing an excess of phosphine to react with magnesium under nitrogen. Substitution reactions with CO and p-tolylisocyanide were studied, and led to Mo(CO)₂P₄, Mo(CO)₃P₃, and Mo(p-tolylNC)₂P₄ derivatives. Treatment of dinitrogen compound Mo(N₂)₂[PPh(OEt)₂]₄ with an excess of HCl gave the hydrazido(2-) [MoCl(NNH₂){PPh(OEt)₂}₄]Cl derivative. Reduction reactions with zinc amalgam of complexes 1 and 2 in the presence of lutidine·HCl gave ammonia in about 8-10% yield.     

Metal assisted deprotonation of a β-phosphonato-phosphine ligand. X-ray structure of Pd(II) complexes with new P,O donor ligands

The new diethyl-{(diphenylphosphino)phenyl}methylphosphonate ligand, rac-Ph₂PCH(Ph)P(O)(OEt)₂ 1, has been prepared and coordinated to a Pd(II) metal centre to form P,O chelates involving P(III) and P(V) centres, as established by X-ray diffraction of cis-[Pd{Ph₂PCH(Ph)P(O)(OEt)₂-κ²-P,O }₂](BF₄)₂ 2. Deprotonation of P-bound 1 led to the first anionic β-phosphonato-phosphine P,O chelate, which was characterised by X-ray diffraction in complex [(dmba)Pd{Ph₂PC(Ph)PO(OEt)₂-κ²-P,O }] 4. To cite this article: X. Morise et al., C.R. Chimie 6 (2003) 000–000.     

Synthesis and reactivity of germyl complexes of manganese and rhenium

Trichlorogermyl complexes M(GeCl₃)(CO)_nP_{5? n} (1–4) [M = Mn, Re; n = 2, 3; P = PPh(OEt)₂ (a), P(OEt)₃ (b)] were prepared by allowing chloro compounds MCl(CO)_nP_{5? n} to react with an excess of GeCl₂?dioxane in 1,2-dichloroethane. Treatment of compounds 1–4 with LiAlH₄ in thf yielded trihydridegermyl derivatives M(GeH₃)(CO)_nP_5?n (5–8), whereas treatment of the same complexes with NaBH₄ in ethanol afforded triethoxygermyl derivatives M[Ge(OEt)₃](CO)_nP_5?n (9–11). Trimethylgermyl compounds M(GeMe₃)(CO)_nP_5?n (12, 13) and the alkynylgermyl derivative Mn[Ge(CCPh)₃](CO)₃[PPh(OEt)₂]₂ (14a) were also prepared by allowing trichlorogermyl compounds 1–4 to react with either MgBrMe or Li⁺CCPh^?, respectively, in thf. Treatment of compound Re(GeCl₃)(CO)₃[PPh(OEt)₂]₂ (4a) with SnCl₂?2H₂O gave the stannyl-germyl derivative Re[GeCl₂(SnCl₃)](CO)₃[PPh(OEt)₂]₂ (15a). The complexes were characterised by spectroscopy and X-ray crystal structure determination of 4a, 5a, and 13a.     

Synthesis and reactivity of germyl complexes of manganese and rhenium

Trichlorogermyl complexes M(GeCl₃)(CO)_nP_{5− n} (1–4) [M = Mn, Re; n = 2, 3; P = PPh(OEt)₂ (a), P(OEt)₃ (b)] were prepared by allowing chloro compounds MCl(CO)_nP_{5− n} to react with an excess of GeCl₂•dioxane in 1,2-dichloroethane. Treatment of compounds 1–4 with LiAlH₄ in thf yielded trihydridegermyl derivatives M(GeH₃)(CO)_nP_5−n (5–8), whereas treatment of the same complexes with NaBH₄ in ethanol afforded triethoxygermyl derivatives M[Ge(OEt)₃](CO)_nP_5−n (9–11). Trimethylgermyl compounds M(GeMe₃)(CO)_nP_5−n (12, 13) and the alkynylgermyl derivative Mn[Ge(CCPh)₃](CO)₃[PPh(OEt)₂]₂ (14a) were also prepared by allowing trichlorogermyl compounds 1–4 to react with either MgBrMe or Li⁺CCPh⁻, respectively, in thf. Treatment of compound Re(GeCl₃)(CO)₃[PPh(OEt)₂]₂ (4a) with SnCl₂•2H₂O gave the stannyl-germyl derivative Re[GeCl₂(SnCl₃)](CO)₃[PPh(OEt)₂]₂ (15a). The complexes were characterised by spectroscopy and X-ray crystal structure determination of 4a, 5a, and 13a.     

A novel access to the anionic permethylated fac-tripod ligand [C5Me5Co&P(O)(OEt)2&3]−, and its derived trinuclear and binuclear complexes

[C₅Me₅Co&P(O)(OEt)₂&₃]Co(II) was obtained in high yield from the reaction of C₅Me₅Li with Co(acac)₃ and diethylphosphite in a one-step synthesis. This provides high-yield synthetic routes to several decamethylated triple-decker sandwiches [C₅Me₅Co&P(O)(OEt)₂&M [M = Co(III) or Ti(IV)], and pentamethylated binuclear complexes [C₅Me₅Co&P(O)(OEt)₂&₃]M′L_n, &M′L_n = [Re(CO)₃]⁺, [VO(acac)]⁺ or [Ru(η-C₆Me₆)]²⁺&.     

Preparation method effect on the properties of Ziegler-type hydrogenation catalysts based on bis(acetylacetonato)cobalt

The turnover frequency and turnover number of Ziegler-type systems based on Co(acac)₂ · nH₂O (n = 0, 0.5, and 2) and AlEt₃ or AlEt₂(OEt) are reported in relation to the Al: Co molar ratio and to the concentrations of the initial components. Proton donor compounds have an effect on the catalytic characteristics of the systems. ESR data are presented for the interaction of Co(acac)₂ with organometallic compounds (AlEt₃, AlEt₂(OEt), Li(n-Bu), and (C₆H₅CH₂)MgCl) in the presence of various arenes. Seven preparation methods and a formation scheme are suggested for catalytic species that are active in styrene hydrogenation and are based on Co(acac)₂ combined with AlEt₃ or AlEt₂(OEt) and.     

Silicon and phosphorus alkoxide mixture: Sol-gel study by spectroscopic technics

Sol-gel synthesis of mixtures of tetraethoxysilane and a phosphorus alkoxide [P(OEt)₃ or (OEt)₂P-O-P(OEt)₂ or PO(OEt)₃] have been studied by ¹H, ¹³C²⁹Si and ³¹P liquid and solid state NMR, infrared and raman spectroscopies. This study shows different behaviors towards hydrolysis for these three different phosphates and phosphites. P(OEt)₃ almost instantly reacts with water to form an intermediate species HPO(OEt)₂, which slowly evolves first to HPO(OH)(OEt), then to HPO(OH)₂ a few days later. For (OEt)₂P-O-P(OEt)₂, the P-O-P bond is broken when water is added, then the same intermediates are formed faster. PO(OEt)₃ is hydrolyzed much slower than the other alkyl phosphates. After ten months, triethoxyphosphate is quantitatively present in the sol with little PO(OH)(OEt)₂ species. All these hydrolyzed species are well characterized. Only the system which contains the tetraethoxysilane and the triethoxyphosphite P(OEt)₃ forms a few P-O-P and P-O-Si bonds in the gel. Hydrolysis of tetraethoxysilane is much faster than that of phosphorus alkoxides and the conventional Q₂, Q₃ and Q₄ condensed silicon species form the gel three dimensional network.     

Mono- and bis-alkoxides of tris(3,5-dimethylpyrazolyl)borato molybdenum and tungsten nitrosyls

The complexes [ML^*(NO)Cl(OR)] {L^* = HB(3,5-Me₂C₃HN₂)₃; M= Mo, R = CH₂CH₂X, X = Cl, OMe or OEt; (CH₂)_nOH, n = 2, 5, 6; M = W, R = CH₂CH₂X, X = Cl, OMe or OEt; (CH₂)_nOH, n = 2–6; CH₂(CF₂)₃CH₂OH; CHMeCH₂CMe₂OH} and [ML^*(NO)(OR)₂] {M = Mo, R = CH₂CH₂X, X = Cl, OMe or OEt; (CH₂)_nOH, n = 2–6; M = W,R = CH₂CH₂X, X= Cl, OMe or OEt; (CH₂)_nOH, n = 2,4–6; CH₂(CF₂)₃CH₂OH} have been prepared from [ML^*(NO)Cl₂] and the appropriate alcohol in the presence of NEt₃ or NaCO₃, and have been characterized by IR, ¹H NMR and mass spectroscopy.     

Preparation and reactivity of half-sandwich hydrazine complexes of ruthenium and osmium

Hydrazine complexes [MCl(η⁶-p-cymene)(RNHNH₂)L]BPh₄ (1–6) [M = Ru, Os; R = H, Me, Ph; L = P(OEt)₃, PPh(OEt)₂, PPh₂OEt] were prepared by allowing dichloro complexes MCl₂(η⁶-p-cymene)L to react with hydrazines RNHNH₂ in the presence of NaBPh₄. Treatment of ruthenium complexes [RuCl(η⁶-p-cymene)(RNHNH₂)L]BPh₄ with Pb(OAc)₄ led to acetate complex [Ru(κ²–O₂CCH₃)(η⁶-p-cymene)L]BPh₄ (7). Instead, the reaction of osmium derivatives [OsCl(η⁶-p-cymene)(CH₃NHNH₂)L]BPh₄ with Pb(OAc)₄ afforded the methyldiazenido complex [Os(CH₃N₂)(η⁶-p-cymene)L}]BPh₄ (8). Treatment with HCl of this diazenido complex 8 led to the methyldiazene cation [OsCl(CH₃NNH)(η⁶-p-cymene)L}]⁺ (9⁺). The complexes were characterised spectroscopically and by X-ray crystal structure determination of [OsCl(η⁶-p-cymene)(PhNHNH₂){PPh(OEt)₂}]BPh₄ (6b) and [Ru(κ²–O₂CCH₃)(η⁶-p-cymene){PPh(OEt)₂}]BPh₄ (7b).     

On the interaction of tetraethoxosilane with metal alkoxides: Sol-gel synthesis of alkaline-earth metal silicates

Physicochemical analyses (solubility method, conductometry, and IR spectroscopy) revealed no complex formation in M(OR)_n-Si(OR)₄-ROH systems (M = Na, Ba, Al; R = Et, Prⁱ), unlike in the systems containing alkoxides of two metals. IR and NMR spectroscopy showed that Si(OR)₄ became reactive only due to microhydrolysis, which is accompanied most likely by the formation of intermediates (asymmetric molecules [Si(OH)_n(OR)_{4 ? n} ]). The hydrolysis was studied for model systems M(OEt)₂ ? si(OEt)₄ (M = Ba, Ca), and conditions for the synthesis of silicates were optimized.     

Efficient synthesis of the siderophore petrobactin via antimony triethoxide mediated coupling

Chemical synthesis of petrobactin, a siderophore for Bacillus anthracis, has been achieved via Sb(OEt)₃-mediated ester–amide exchange.     

Kinetic studies on the reactions of Ru(II) tetraammines with CS2N−3

The kinetics of the reactions of Ru(II) complexes with CS₂N⁻₃ ions were studied spectrophotometrically. The formation rate constants data for trans-[Ru(NH₃)₄L(CS₂N₃)] are 2.2 × 10², 1.8 × 10 and 1.3 × 10² M⁻¹ s⁻¹ for L = SO^2-₃, HSO⁻₃ and P(OEt)₃), respectively [μ = 1.0 M (NaCF₃COO), 25°C]. Under the same experimental conditions, the values of k⁻¹ (specific rate for the aquation reaction) are 1.5 × 10⁻², 5.0 × 10⁻² and 4.5 × 10 s⁻¹ for L = SO²⁻₃, HSO⁻₃ and P(OEt)₃, respectively. The free-energy change (ΔG^≠) for the systems where L = P(OEt)₃ and SO²⁻₃ are in agreement within the experimental error. It was observed that the affinity of the CS₂N⁻₃ ion decreases with the increasing π-acidity of the auxiliary ligand L. The order of affinity of the CS₂N⁻₃ ion for the Ru(II) center studies is SO²⁻₃ > HSO⁻₃ > P(OEt)₃ >SO₂.     

Preparation of imine complexes of ruthenium and osmium stabilised by [MCl(η -p-cymene)(PR3)] fragments

Imine complexes [MCl(η ⁶-p-cymene){η¹-NHC(H)Ar}(PR₃)]BPh₄ (1-3) [M = Ru, Os; PR₃ = PPh(OEt)₂, PPh₂OEt; Ar = Ph, p-tolyl] were prepared by reacting MCl₂(η ⁶-p-cymene)(PR₃) precursors with benzyl azide ArCH₂N₃ in the presence of NaBPh₄. Benzophenone-imine complexes [MCl(η ⁶-p-cymene){η¹-NHCPh₂}(PR₃)]BPh₄ (4-6) [M = Ru, Os; PR₃ = PPh(OEt)₂, PPh₂OEt] were also prepared by allowing MCl₂(η ⁶-p-cymene)(PR₃) to react with Ph₂CNH in the presence of NaBPh₄. The complexes were characterised spectroscopically (IR, ¹H, ¹³C, ³¹P, ¹⁵N NMR) and by X-ray crystal structure determination of [RuCl(η ⁶-p-cymene){η¹-NHC(H)-p-tolyl}{PPh(OEt)₂}]BPh₄ (1b).     

Stereochemical studies on the nucleophilic substitution in the reaction of allyl phosphates with organoaluminium reagents

The reaction of cis- or trans-5-isopropenyl-2-methyl-2-cyclohexenyl diethyl phosphate (I) with Me₂AlX (X = OPh, SPh, NHPh) in hexane results in substitution of the -O-PO(OEt)₂ group with X under predominant inversion. The solvent effects on the stereochemistry in these reactions have been disclosed.     

Schwingungsspektren von Alkoxostibanen

Vibrational Spectra of Alkoxostibanes The vibrational spectra of the ethoxostibanes Sb(OEt)₃ ( 1 ), Sb(OEt)₂Cl ( 2 ), SbOEtCl₂ ( 3 ), Sb(OEt)₂Br ( 4 ), SbOEtBr₂ ( 5 ), and Sb(OEt)₂I ( 6 ) were assigned with the aid of the known structures of 2 and 3 in the solid state. The structures of 5 and 6 , which were prepared by new methods, differ from those of the corresponding chloro compounds. The coordination number of antimony in 5 and 6 is probable 5 and 4 resp.     

Synthesis and Hydrolysis of Hybridized Silicon Alkoxide: Si(OEt)x(OBut)4-x. Part II: Hydrolysis of the Si(OEt)x(OBut)4-x

The hydrolyzation behavior of the Si(OEt)_x(OBu^t)_4-x synthesized in part I was investigated by gas chromatogram/mass spectrum (GC/MS) technique. In the Si(OEt)_x(OBu^t)_4-x, Si(OEt)(OBu^t)₃ showed more rapid hydrolysis than Si(OEt)₂(OBu^t)₂, especially in the initial stages of the hydrolyzation. The dimer and trimer formations along with the sol-gel course were followed during the hydrolyzation process.     

Hydrolysis-Polycondensation in Binary Phosphorus Alkoxides—TEOS System Studied by GC-MS

It is well known that various phosphorus precursors exhibit different reactivities towards hydrolysis-polycondensation in acidic media. The hydrolysis-condensation in binary P-alkoxides—TEOS system was studied by GC-MS, in relation to the mentioned reactivity. As P-precursors, the following reagents were used: PO(OMe)₃, PO(OEt)₃, PO(OBu)₃, P(OEt)₃ and HOP(OMe)₂. PO(OMe)₃, PO(OEt)₃ and PO(OBu)₃ do not hydrolyze, but change the TEOS hydrolysis-polycondensation ratio. P(OEt)₃ partially hydrolyzes and transforms into a very stable HOP(OEt)₂ form, while HOP(OMe)₂ reacts very fast with nonparental solvent and undergoes transesterification. Si–O–P bonds have not been observed in early stages of hydrolysis-polycondensation. However, the gelling tendency is strongly influenced by the P-precursor.     

Formation of pyrrolidines by the titanocene(II)-promoted intramolecular reaction of N-[3,3-bis(phenylthio)propyl]anilides

The reaction of anilides with the titanium carbene complexes generated by the desulfurization of thioacetals with the titanocene(II) species Cp₂Ti[P(OEt)₃]₂ produced the corresponding enamines. Unusual formation of pyrrolidines was observed when N-[3,3-bis(phenylthio)propyl]anilides were treated with the titanocene(II) reagent.