Phosphorus-carbon(pyridyl) bond cleavage on reacting diphenyl-2-pyridylphosphine with triiron dodecacarbonyl

The reaction of [Fe₃(CO)₁₂] with diphenyl-2-pyridylphosphine (PPh₂Py) in refluxing toluene for 1 h afforded three compounds, [Fe₂(CO)₆(μ-PPh₂)(μ-κ²-C,N-C₅H₄N)] (1), [Fe(CO)₄(κ¹-P-PPh₂Py)] (2), and [Fe(CO)₃(κ¹-P-PPh₂Py)₂] (3) in 23%, 10% and 3.5% yields after work-up, respectively. The PPh₂Py ligand acts as a terminal P-donor ligand in 2 and 3, while in 1 it underwent a selective phosphorus-carbon(pyridyl) bond cleavage to afford phosphido- and pyridyl-bridged ligands. The complexes were characterized by elemental analysis, FAB-mass, FTIR, ¹H and ³¹P-{¹H}NMR spectroscopies. Compounds 1 and 2 were also characterized by X-ray single crystal.     

Neighbouring metal induced oxidative addition at the iron centre amongst the iron-arylpyridylphosphine complexes

Complexes of the type (η⁴-BuC₅H₅)Fe(CO)₂(P) (P = PPh₂Py 3, PPhPy₂4, PPy₃5; Py = 2-pyridyl) were satisfactorily prepared. Upon treatment of 3 with M(CO)₃(EtCN)₃ (M = Mo, 6a; W, 6b), the pyridyl N-atom could be coordinated to the metal M, which then eliminates a CO ligand from the Fe-centre and induced an oxidative addition of the endo-C-H of (η⁴-BuC₅H₅). This results in a bridged hydrido heterodimetallic complex [(η⁵-BuC₅H₄)Fe(CO)(μ-P,N-PPh₂Py)(μ-H)M(CO)₄] (M = Mo, 7a, 81%; W, 7b, 76%). The reaction of 4 or 5 with 6a,b did not give the induced oxidative addition, although these complexes contain more than one pyridyl N-atom. The reaction of 4 with M(CO)₄(EtCN)₂ (M = Mo, 9a; W, 9b) produced heterodimetallic complexes [(η⁴-BuC₅H₅)Fe(CO)₂(μ-P:N,N′-PPhPy₂)M(CO)₄] (M = Mo, 10a, 81%; W, 10b, 83%). Treatment of 5 with 6a,b gave [(η⁴-BuC₅H₅)Fe(CO)₂(μ-P:N,N′,N″-PPy₃)M(CO)₃] (M = Mo, 12a, 96%; W, 12b, 78%).     

Intramolecular exchange of coordinated and dangling phosphines in pentacarbonyl group 6 complexes of 1,1,2-tris(diphenylphosphino)ethane

The linkage isomers, (OC)₅M[κ¹-PPh₂ CH₂CH(PPh₂)₂] 1 and (OC)₅M[κ¹-PPh₂ CH(PPh₂)CH₂PPh₂] 2 (M = Cr, Mo and W) exist in equilibrium at room temperature. Equilibrium constants for 1Cr ? 2Cr, 1Mo ? 2Mo and 1W ? 2W at 25 °C in CDCl₃ are 2.61, 5.0 and 4.74, respectively. Enthalpy favors the forward reaction (ΔH = −13.5, −12 and −12.2 kJ mol⁻¹, respectively) while entropy favors the reverse reaction (ΔS = −37.6, −28 and −28.2 J K⁻¹ mol⁻¹, respectively). Isomerization is much faster than chelation with 1Mo ? 2Mo ? 1W ? 2W > 1Cr ? 2Cr. Enthalpies of activation for 1Cr ? 2Cr and 1W ? 2W are 119.0 and 92.6 kJ mol⁻¹, respectively, and entropies of activation are 1.4 and −28.2 J K⁻¹ mol⁻¹, respectively. Isomerization is 10⁴ times faster for these complexes than for (OC)₅M[κ¹-PPh₂CH₂CH₂P(p-tolyl)₂]. A novel mechanism is proposed to account for the rate differences. The X-ray crystal structure of 2W shows that the phosphorus atom of the short phosphine arm lies very close to a carbon atom of the W(CO)₄ equatorial plane (3.40 Å) which could allow “through-space” coupling, accounting in part for the observation of long-range J_PC and J_PW coupling. The X-ray structure of (OC)₅W[κ¹-PPh₂ C(CH₂)PPh₂] 5W has been determined for comparison to 2W.     

On the identification of ionic species of neutral halogen dimers, monomers and pincer type palladacycles in solution by electrospray mass and tandem mass spectrometry

Electrospray (ESI) mass spectra analysis of acetonitrile solutions of a series of neutral chloro dimers, pincer type, and monomeric palladacycles has enabled the detection of several of their derived ionic species. The monometallic cationic complexes Pd[κ¹-C,κ¹-N,κ¹-S-C(CH₃S-2-C₆H₄)C(Cl)CH₂N(CH₃)₂]⁺ (1a) and [Pd[κ¹-C,κ¹-N,κ¹-S-C(CH₃S-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](CH₃CN)]⁺ (1b) and the bimetallic cationic complex [κ¹-C,κ¹-N,κ¹-S-C(CH₃S-2-C₆H₄)C(Cl)CH₂N(CH₃)₂]Pd-Cl-Pd[κ¹-C,κ¹-N,κ¹-S-C(CH₃S-2-C₆H₄)C(Cl)CH₂N(CH₃)₂]⁺ (1c) were detected from an acetonitrile solution of the pincer palladacycles Pd[κ¹-C,κ¹-N,κ¹-S-C(CH₃S-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](Cl) 1. For the dimeric compounds {Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](μ-Cl)}₂ (2, Y=H and 3, CF₃), highly electronically unsaturated palladacycles [Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂]⁺ (2d, 3d) and their mono and di-acetonitrile adducts, namely, [Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](CH₃CN)]⁺ (2e, 3e) and [Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](CH₃CN)₂]⁺ (2f and 3f) were detected together with the bimetallic complex [Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂]-Cl-Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N](CH₃)₂]⁺ (2a, 3a) and its acetonitrile adducts [κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](CH₃CN)Pd-Cl-Pd[ κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂]⁺ (2b, 3b) and [κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](CH₃CN)Pd-Cl-Pd[κ¹-C, κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂(CH₃CN)]⁺ (2c, 3c). The dimeric palladacycle {Pd[κ¹-C,κ¹-N-C(CH₃O-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](μ-Cl)}₂ (4) is unique as it behaves as a pincer type compound with the OCH₃ substituent acting as an intramolecular coordinating group which prevents acetonitrile full coordination, thus forming the cationic complexes [(C₆H₄(o-CH₃O)CC(Cl)CH₂N(CH₃)₂-κO,κC,κN)Pd]⁺ (4b), [(C₆H₄(o-CH₃O)CC(Cl)CH₂N(CH₃)₂- κO,κC,κN)Pd(CH₃CN)]⁺ (4c) and [(C₆H₄ (o-MeO)CC(Cl)CH₂N(CH₃)₂-κO, κC,κN)Pd-Cl-Pd(C₆H₄(o-CH₃O)CC(Cl)CH₂N(CH₃)₂-κO,κC,κN)]⁺ (4a). ESI-MS spectra analysis of acetonitrile solutions of the monomeric palladacycles Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](Cl)(Py) (5, Y=H and 6, Y=CF₃) allows the detection of some of the same species observed in the spectra of the dimeric palladacycles, i.e., monometallic cationic 2d-3d, 2e-3e and {Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](Py)}⁺ (5a, 6a) and {Pd[κ¹-C,κ¹-N-C(Y-2-C₆H₄)C(Cl)CH₂N(CH₃)₂](CH₃CN)(Py)}⁺ (5b, 6b) and the bimetallic 2a, 3a, 2b, 3b, 2c and 3c. In all cationic complexes detected by ESI-MS, the cyclometallated moiety was intact indicating the high stability of the four or six electron anionic chelate ligands. The anionic (chloride) or neutral (pyridine) ligands are, however, easily replaced by the acetonitrile solvent.     

Phosphorus-carbon bond formation via reactions of triphenylphosphine with acetylene and pentamethylcyclopentadienyl coordinated to iridium(III)

Phosphorus-carbon bond is formed via: (i) the apparent HCCH insertion into Ir-P bond to produce Ir-CHCH-PPh₃ group and (ii) the activation of the ring-methyl group of the coordinated Cp^* (C₅Me₅ ⁻) to produce Ir(η⁵-C₅Me₄CH₂-PPh₃) group from reactions of iridium(III)-Cp^* complexes, [Cp^*IrL₃]ⁿ⁺ (n=1, 2); Cp^*=C₅Me₅ ⁻; L₃=Cl(PPh₃)₂ (3), (CH₃CN)₃ (5). The following new P-C bond containing iridium(III) complexes have been prepared: [Cp^*Ir(-CHCH-PPh₃)Cl(PPh₃)]⁺ (4) from 3 with HCCH; [Ir(η⁵-C₅Me₄CH₂-PPh₃)(H)(PPh₃)₂]²⁺ (6) from 5 with PPh₃; [Cp^*Ir(-CHCH-PPh₃)₂(PPh₃)]²⁺ (7) from 5 with HCCH and PPh₃; [Ir(η⁵-C₅Me₄CH₂-PPh₃)(-CHCH-PPh₃)Cl(PPh₃)]²⁺ (8) from [Ir(η⁵-C₅Me₄CH₂-PPh₃)(Cl)(PPh₃)₂]²⁺ (6-Cl) with HCCH; [Ir(η⁵-C₅Me₃(1,3-CH₂-PPh₃)₂(H)(PPh₃)₂)]³⁺ (10) from [Ir(η⁵-C₅Me₄CH₂-PPh₃)(NCCH₃)₂(PPh₃)]³⁺ (9) with PPh₃; [Ir(η⁵-C₅Me₄CH₂-PPh₃)(-CHCH-PPh₃)₂(PPh₃)]³⁺ (11) from 9 with HCCH and PPh₃.     

Copper(I)-imine complexes: Synthesis and catalytic activity in olefin cyclopropanation

Different imine-type ligands, prepared by the condensation of anilines or of α-methylbenzylamine with 2-pyridinecarboxaldehyde (pyim^1,2) or 2-quinolinecarboxaldehyde (quim^1,2) were prepared. These species act as N,N′-bidentate, chelating ligands upon coordination to Cu(I): treatment of [Cu(PPh₃)₃Cl] with an equimolar amount of the ligands resulted in the displacement of two molecules of PPh₃, giving rise to the formation of [Cu(pyim^1,2)(PPh₃)Cl] (1-2) and [Cu(quim^1,2)(PPh₃)Cl] (3-4), respectively. The copper derivatives 1-4 proved to be highly active catalysts in olefin cyclopropanation in the presence of ethyl diazoacetate, even using deactivated olefins (namely, 2-cyclohexen-1-one) as substrate. The X-ray structure of complex 2, [Cu(pyim²)(PPh₃)Cl], is also reported.     

Rhenium(III) and technetium(III) complexes with 2-mercapto-1,3-azole ligands and X-ray crystal structures

Reactions of labile [MCl₃(PPh₃)₂(NCMe)] (M = Tc, Re) precursors with 1H-benzoimidazole-2-thiol (H₂L¹), 5-methyl-1H-benzoimidazole-2-thiol (H₂L²) and 1H-imidazole-2-thiol (H₂L³), in the presence of PPh₃ and [AsPh₄]Cl gave a new series of trigonal bipyramidal M(III) complexes [AsPh₄]{[M(PPh₃)Cl(H₂L^1-3)₃]Cl₃} (M = Re, 1-3; M = Tc, 4-6). The molecular structures of 1 and 3 were determined by X-ray diffraction. When the reactions were carried out with benzothiazole-2-thiol (HL⁴) and benzoxazole-2-thiol (HL⁵), neutral paramagnetic monosubstituted M(III) complexes [M(PPh₃)₂Cl₂(L^4,5)] (M = Re, 8, 9; M = Tc, 10, 11) were obtained. In these compounds, the central metal ions adopt an octahedral coordination geometry as authenticated by single crystal X-ray diffraction analysis of 8 and 11. Rhenium and technetium complexes 1, 4 and rhenium chelate compounds 8, 9 have been also synthesized by reduction of [MO₄]⁻ with PPh₃ and HCl in the presence of the appropriate ligand. All the complexes were characterized by elemental analyses, FTIR and NMR spectroscopy.     

Antisymbiosis. Preferential coordination of anionic oxygen versus neutral sulfur donor atoms of methylsulfanyl- or methylsulfinyl-acetato, 2-benzoato and 2-phenolato to the cis-Pt(PPh3)2 and Pt(dppe) residues

The interaction of an excess of the title ligands L⁻ with the cis-Pt(phos)₂ moieties gives compounds a-bcis-[Pt(L-O)₂(phos)₂] (a, phos = P(Ph)₃; b, phos = 1/2 dppe), in which O- is preferred to S-coordination. Such preference is confirmed by the fact that the same products are obtained by reaction of excess of L⁻ with the previously reported a-d complexes [Pt(L-O,S)(phos)₂]⁺, (c, phos = PPh₃, d, phos = 1/2 dppe), for which chelate ring opening occurs with rupture of Pt-S rather than Pt-O bonds. Compound a can be obtained also by oxidative addition of HL to [Pt(PPh₃)₃]. The Pt-O bonds in compounds a-d are stable towards substitution by Me₂SO, pyridine and tetramethylthiourea. Substitution of L’s occurs with N,N′-diethyldithiocarbamate, which forms a very stable chelate with Pt(II). Thiourea and N,N′-dimethylthiourea also react, because they give rise to cyclometallated products [Pt(phos)₂(NRC(S)NHR)]⁺ (R = H, CH₃), with one ionised thioamido group, as revealed by an X-ray investigation of [Pt(PPh₃)₂(NHC(S)NH₂)]⁺. The preference of O versus S coordination, as well as the stability of the Pt-O bonds, are discussed in terms of antisymbiosis.     

A cyclic osmastannyl complex, Os(κ(Sn,P)-SnMe2C6H4PPh2)(κ-S2CNMe2)(CO)(PPh3) derived from the osmastannol complex, Os(SnMe2OH)(κ-S2CNMe2)(CO)(PPh3)2

Treatment of the six-coordinate trimethylstannyl complex, Os(SnMe₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (1) with SnMe₂Cl₂ produces Os(SnMe₂Cl)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (2), which in turn reacts readily with hydroxide ion to give, Os(SnMe₂OH)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (3). The osmastannol complex 3 undergoes a reaction with 2 equivalents of ^tBuLi, in which one of the phenyl rings of a triphenylphosphine ligand is “ortho-stannylated”, without cleavage of the Os-Sn bond, to give the cyclic complex, Os(κ²(Sn,P)-SnMe₂C₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (4). This novel cyclic complex is selectively functionalised at the tin atom by reaction with SnMe₂Cl₂ which exchanges one methyl group for chloride giving the diastereomeric mixture, Os(κ²(Sn,P)-SnMeClC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (5a/5b). Crystal structure determination reveals that both diastereomers occur in the unit cell. The mixture, 5a/5b, undergoes reaction with hydroxide ion to give the diastereomeric osmastannol complexes, Os(κ²(Sn,P)-SnMeOHC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (6a/6b) and with sodium borohydride to give the corresponding tin-hydride mixture, Os(κ²(Sn,P)-SnMeHC₆H₄PPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃) (7a/7b). Crystal structure determinations for 2, 4, and 5a/5b have been obtained.     

Stereochemical structure determination of p-cymene Ru(II) complexes containing the PPh2Py ligand with 2-D NOESY and HMQC NMR experiments

Complexes [Ru(p-cymene)Cl₂(PPh₂Py)] (1) and [Ru(p-cymene)Cl(PPh₂Py)]BF₄ (2) were studied by means of ¹H, ¹³C{¹H} 2-D NOESY and HMQC NMR spectral methods. NMR data agree with C₁ and C_s symmetries for complexes 1 and 2, respectively. NOESY cross-peaks allowed the assignment of signals to CH arene protons and in the case of complex 2 the determination of the molecular stereochemistry. These results are in agreement with the X-ray molecular structures of both complexes.     

Synthesis and structures of zinc complexes with new binucleating ligands containing alkoxide bridges, and their activities in the hydrolysis of tris(p-nitrophenyl)phosphate

Four new binucleating ligands featuring a hydroxytrimethylene linker between two coordination sites (1,3-bis{N-[3-(dimethylamino)propyl]-N-methylamino}propan-2-ol, HL¹; 1,3-bis{N-[2-(dimethylamino)ethyl]-N-methylamino}propan-2-ol, HL²; 1,3-bis[bis(2-methoxyethyl)amino]propan-2-ol, HL³; and 1-bis[(2-methoxyethyl)amino]-3-{N-[2-(dimethylamino)ethyl]-N-methylamino}propan-2-ol, HL⁴) were synthesized, along with the corresponding zinc complexes. The structures of three dinuclear zinc complexes ([Zn₂L¹(μ-CH₃COO)₂]BPh₄ (1), [Zn₂L³(μ-CH₃COO)₂]BPh₄ (3), and [Zn₂L⁴(μ-CH₃COO)(CH₃COO)(EtOH)]BPh₄ (4)) and a tetranuclear zinc complex ({[Zn₂L²(μ-CH₃COO)]₂(μ-OH)₂}(BPh₄)₂ (2)) were revealed by X-ray crystallography. Hydrolysis of tris(p-nitrophenyl)phosphate (TNP) by these zinc complexes in an acetonitrile solution containing 5% Tris buffer (pH 8.0) at 30 °C was investigated spectrophotometrically and by ³¹P NMR. Although zinc complexes 1, 3, and 4 did not show hydrolysis activity, the tetranuclear zinc complex 2, containing μ-hydroxo bridges, was capable of hydrolyzing TNP. This suggests that the hydroxide moiety in the complex may have an important role in the hydrolysis reaction.     

First microwave-assisted synthesis of an electron-rich phosphane and its coordination chemistry with platinum(II) and palladium(II)

The P-O ligand 3-(di(2-methoxyphenyl)phosphanyl)propionic acid (HL) was synthesized by a microwave-assisted reaction of a secondary phosphane. The coordination of HL to Pt^II yielded the neutral mononuclear complex trans-[PtCl(κ²-P,O-L)(κ-P-HL)] (1), while the reaction of PdClMe(η⁴-COD) (COD = 1,4-cyclooctadiene) with HL in the presence of NEt₃ gave the anionic Pd^II compound of the formula (HNEt₃)[PdClMe(κ²-P,O-L)] (2). Upon crystallization of the latter compound the neutral chloride-bridged dimetallic compound cis-[Pd(μ-Cl)Me(HL)]₂ (3) was obtained. HL, 1 and 3·CH₂Cl₂ have been characterized by single crystal X-ray structure analyses.     

Syntheses, reactions, and structures of osmium(II) stannyl complexes with the simple stannyl ligands SnH3, SnH2Me, and SnHMe2

Reaction between Os(SnI₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ and NaBH₄ produces the unusual, air-stable, trihydridostannyl complex, Os(SnH₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (1), which has been fully characterised including by X-ray crystal structure determination.Similarly, reaction between Os(SnI₂Me)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ or Os(SnClMe₂)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ and NaBH₄ produces the dihydridostannyl complex, Os(SnH₂Me)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (4) or the monohydridostannyl complex, Os(SnHMe₂)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (6), respectively.The SnH bonds in these complexes are reactive towards acids and in selected reactions complexes 1 and 4 with aqueous HF give Os(SnF₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (3) and Os(SnF₂Me)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (5), respectively, and complex 6 with aqueous HCl gives Os(SnClMe₂)(κ²-S₂CNMe₂)(CO)(PPh₃)₂.The trihydridostannyl complex 1 reacts with chloroform to form the trichlorostannyl complex, Os(SnCl₃)(κ²- S₂CNMe₂)(CO)(PPh₃)₂ (2). The crystal structures of 1-3, 5, and 6 have been determined.     

Rhodium and iridium olefin complexes with bulky cyclopentadienyl and hydrotris(pyrazolyl)borate ligands

The synthesis of a series of rhodium and iridium complexes bearing bulky cyclopentadienyl or hydro(trispyrazolyl)borate ligands is described. The rhodium cyclopentadienyl and hydrotris(pyrazolyl)borate diene compounds, [(η⁵-C₅Me₄Bu^t)Rh(η⁴-2,3-MeRC₄H₄] (R = H, 1; Me, 2) and Tp^MsRh(η⁴-2,3-MeRC₄H₄) (R = H, 3; Me, 4; Tp^Ms is hydrotris(3-mesitylpyrazol-1-yl)borate), respectively, have been prepared from the corresponding Rh(I) diene precursors and Zn(C₅Me₄Bu^t)₂ (for 1 and 2), or TlTp^Ms (for 3 and 4), as effective C₅Me₄Bu^t or Tp^Ms transfer reagents. In contrast with these results, attempts to obtain a bis(ethylene) derivative of the Tp^tolIr(I) unit (Tp^tol stands for hydrotris(3-p-tolylpyrazol-1-yl)borate) have provided instead the Ir(III) complex [(κ⁴-N,N′,N″,C-Tp^tol)-Ir(C₂H₅)(C₂H₄)] (5), whose formation requires C-H bond activation of a molecule of ethylene and of one of the Tp^tolp-tolyl substituents. In refluxing toluene 5 experiences metalation of a second p-tolyl substituent to give [(κ⁵-N,N′,N″,C,C′-Tp^tol)-Ir(C₂H₄)] (6), which features unusual κ⁵-Tp^tol coordination. The latter compound reacts with carbon monoxide to yield the corresponding carbonyl, 7.     

Structural variety and stereochemical features of bis(diphenylphosphinyl)[3]ferrocenophane gold(I) complexes

The P,N-[3]ferrocenophane ligand 3 forms a (κP-ligand)AuCl complex (5) upon treatment with (Me₂S)AuCl. The corresponding P,P-[3]ferrocenophane system 4 yields a binuclear (κP,κP-chelate ligand)(AuCl)₂ complex (6) when reacted with 2 equivalents of the (Me₂S)AuCl reagent. Complex 6 features an intramolecular aurophilic Au?Au interaction. Treatment of the P,P-[3]ferrocenophane 4 with 1.0 equiv. of (PPh₃)AuCl gives the tetra-coordinated mono-gold(I) complex (P,P-ligand)(PPh₃)AuCl (7), whereas the cationic [(P,P-ligand)₂Au]⁺[Cl⁻] system is obtained from 4 and 0.5 equivalents of (Me₂S)AuCl. The [(P,P-ligand)₂Au]⁺ system is obtained in different diastereoisomeric forms (8 and 9) depending on the stereochemistry of the pair of P,P-[3]ferrocenophane chelate ligand used. Examples of the complexes 5, 6, 7 and 8 were characterized by X-ray diffraction.     

Complexes of N-thiophosphorylthioureas RNHC(S)NHP(S)(OiPr)2 (HL) (R = pyridin-2-yl, pyridin-3-yl, 6-amino-pyridin-2-yl) with copper(I): Crystal structures of Cu(PPh3)nL (n = 1, 2)

Reaction of the potassium salts of N-thiophosphorylated thioureas of common formula RNHC(S)NHP(S)(OiPr)₂ [R = pyridin-2-yl (HL^a), pyridin-3-yl (HL^b), 6-amino-pyridin-2-yl (HL^c)] with Cu(PPh₃)₃I in aqueous EtOH/CH₂Cl₂ leads to mononuclear [Cu(PPh₃)₂L^a,b-S,S′] (1, 2) and [Cu(PPh₃)L^c-S,S′] (3) complexes. Using copper(I) iodide instead of Cu(PPh₃)₃I, polynuclear complexes [Cu_n(L-S,S′)_n] (4-6) were obtained. The structures of these compounds were investigated by IR, ¹H, ³¹P{¹H} NMR spectroscopy, ES-MS and elemental analyses. The crystal structures of Cu(PPh₃)₂L^b (2) and Cu(PPh₃)L^c (3) were determined by single-crystal X-ray diffraction.     

Hybrid scorpionate/cyclopentadienyl titanium and zirconium complexes with alkoxide and imido ligands

The reactivity of hybrid scorpionate/cyclopentadienyl ligand-containing trichloride zirconium complexes [ZrCl₃(bpzcp)] (1) [bpzcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethylcyclopentadienyl] and [ZrCl₃(bpztcp)] (2) [bpztcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1-tert-butylethylcyclopentadienyl] toward several lithium alkoxides has been carried out. Thus, alkoxide-containing complexes [ZrCl₂(OR)(bpzcp)] (R = Me, 3; Et, 4; ⁱPr, 5; (R)-2-Bu, 6), [ZrCl₂(OR)(bpztcp)] (R = Me, 7; Et, 8; ⁱPr, 9; (R)-2-Bu, 10) and [Zr(OR)₃(bpztcp)] (R = Et, 11; ⁱPr, 12) were prepared by deprotonation of the appropriate alcohol group with BuⁿLi followed by reaction with 1 or 2. In addition, the imido-complex [Ti(N^tBu)Cl(bpztcp)(py)] (13) were also prepared. The structures of these complexes have been proposed on basis of spectroscopic and DFT methods.     

Osmadisiloxane and osmastannasiloxane complexes derived from silanolate complexes of osmium(II)

Treatment of the five-coordinate chlorodimethylsilyl complex, Os(SiMe₂Cl)Cl(CO)(PPh₃)₂ with hydroxide readily produces Os(SiMe₂OH)Cl(CO)(PPh₃)₂ (1). Complex 1 is deprotonated by ^tBuLi giving the silanolate complex, Os(SiMe₂OLi)Cl(CO)(PPh₃)₂ (2), which reacts further with Me₃SiCl or Me₃SnCl to give Os(SiMe₂OSiMe₃)Cl(CO)(PPh₃)₂ (3) or Os(SiMe₂OSnMe₃)Cl(CO)(PPh₃)₂ (4), respectively. The structures of 3 and 4 have been determined by X-ray crystallography. Reaction between OsH(κ²-S₂CNMe₂)(CO)(PPh₃)₂ and HSiMe₂Cl gives Os(SiMe₂Cl)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (5). This six-coordinate chlorodimethylsilyl complex, is unreactive towards hydroxide at room temperature and at 60 °C forms Os[Si(OH)₃](κ²-S₂CNMe₂)(CO)(PPh₃)₂ (7). Complex 5 is, however, smoothly converted to the hydroxy derivative, Os(SiMe₂OH)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (6) upon chromatography on silica gel. Complex 6 is deprotonated by ^tBuLi giving the intermediate silanolate complex, Os(SiMe₂OLi)(κ²-S₂CNMe₂)(CO)(PPh₃)₂, which reacts further with Me₃SiCl to give Os(SiMe₂OSiMe₃)(κ²-S₂CNMe₂) (CO)(PPh₃)₂ (8). Crystal structure determinations for 5, 6, 7, and 8 have been obtained and structural comparisons of these related compounds are made.     

Syntheses and characterization of titanium malonato and amino acid complexes: [Ti(cp)2(OOCCH2NMe2)] - The first structurally characterized α-amino acid titanium(III) complex

The reaction of [Ti(cp^∗)₂(BTMSA)] (1) (cp^∗ = η⁵-C₅Me₅, BTMSA = bis(trimethylsilyl)acetylene) with malonic acids ((HOOC)₂CR₂, R = H, Me) and N,N-dimethylglycine resulted in the formation of titanium(IV) dicarboxylato complexes [Ti(cp^∗)₂{(OOC)₂CR₂}] (R = H, 2; R = Me, 3) and an α-amino acid titanium(III) complex [Ti(cp^∗)₂(OOCCH₂NMe₂)] (4). The identities of complexes 2-4 were confirmed by microanalysis, ¹H and ¹³C NMR spectroscopy (2, 3), ESI-MS and CID experiments (2, 3) as well as by ESR and magnetic measurements (μ_eff = 1.81, 298 K) for 4. Single X-ray diffraction analyses of 2 and 4 exhibited monomolecular complexes in which the titanium atom is distorted tetrahedrally coordinated by two η⁵-C₅Me₅ rings and by the chelating bound malonato-κ²O,O′ (2) and N,N-dimethylglycinato-κ²O,O′ ligand (4).     

Synthesis and isomerisation of two metallated N,O-complexes of ruthenium: Models for the Murai reaction

Two isomers of the N,O-coordinated acetylpyrrolyl complex [Ru(PPh₃)₂(CO)(NC₄H₃C(O)CH₃)H] {cis-N,H (1) and trans-N,H (2)} have been prepared as models for catalytic intermediates in the Murai reaction. Complex 2 isomerises to 1 upon heating via a dissociative pathway (ΔH^‡ = 195 ± 41 kJ mol⁻¹; ΔS^‡ = 232 ± 62 J mol⁻¹ K⁻¹); the mechanism of this process has been modeled using density functional calculations. Complex 2 displays moderate catalytic activity for the Murai coupling of 2′-methylacetophenone with trimethylvinylsilane, but 1 proved to be catalytically inactive under the same conditions.