Synthesis and coordination of the bifunctionalized ylides Ph2P(CH2)n(Ph)2PCHCOOMe (n = 1, 2) and ketenylidene Ph2P(CH2)2(Ph)2PCCO to Pd and Pt complexes

In this paper it is reported the synthesis of the phosphonium salts [Ph₂P(CH₂)_n(Ph)₂PCH₂COOMe]Br (n = 1 (1), 2 (2)) and [Ph₂P(CH₂COOMe)(CH₂)_n(Ph)₂PCH₂COOMe]Br₂ (n = 3 (3)) derived from the reactions of the diphosphines dppm, dppe and dppp with methyl bromoacetate. By reaction of the monophosphonium salt of dppm and dppe with the strong base Na[N(SiMe₃)₂] the corresponding carbonyl stabilized ylides Ph₂P(CH₂)_n(Ph)₂PCHCOOMe (n = 1 (4), 2 (5)) were obtained. The Ph₂P(CH₂)₂(Ph)₂PCHCOOMe (5) ylide was reacted with Pd(II) and Pt(II) substrates. From these reactions were isolated exclusively complexes in which the ylide was chelated to the metal through the free phosphine group and the ylidic carbon atom. A further reaction of the Ph₂P(CH₂)₂(Ph)₂PCHCOOMe (5) ylide with 1.5 equiv. of Na[N(SiMe₃)₂] gives the bifunctionalized ketenylidene Ph₂P(CH₂)₂(Ph)₂PCCO (6) system. This cumulenic ylide reacts with Pt(II) complexes to form a chelated derivative in which IR and NMR spectra suggest the breaking of the CC bond of the -CCO group.     

Sn-S and Ru-Ru bonds cleavage reactions between [Ph3SnS(CH2)3SSnPh3] and Ru3(CO)12: X-ray crystal structures of [Ph3SnS(CH2)3SSnPh3] and trans-[Ru(CO)4(SnPh3)2]

The organotin complex [Ph₃SnS(CH₂)₃SSnPh₃] (1) was synthesized by PdCl₂ catalyzed reaction between Ph₃SnCl and disodium-1,3-propanedithiolate which in turn was prepared from 1,2-propanedithiol and sodium in refluxing THF. Reaction of 1 with Ru₃(CO)₁₂ in refluxing THF affords the mononuclear complex trans-[Ru(CO)₄(SnPh₃)₂] (2) and the dinuclear complex [Ru₂(CO)₆(μ-κ²-SCH₂CH₂CH₂S)] (3) in 20 and 11% yields, respectively, formed by cleavage of Sn-S bond of the ligand and Ru-Ru bonds of the cluster. Treatment of pymSSnPPh₃ (pymS = pyrimidine-2-thiolate) with Ru₃(CO)₁₂ at 55-60 °C also gives 2 in 38% yield. Both 1 and 2 have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction analysis.     

Mononuclear and dinuclear iridium and heterodinuclear iridium-rhodium complexes derived from 1,4-C6H4(CCSiMe3)2 as precursor

The labile iridium(I) precursor trans-[IrCl(C₈H₁₄)(PiPr₃)₂] (2), prepared in situ from [IrCl(C₈H₁₄)₂]₂ (1) and PiPr₃, reacted with equimolar amounts of 1,4-C₆H₄(CCSiMe₃)₂ (3) at 60 °C to give the mononuclear vinylidene complex trans-[IrCl(CC(SiMe₃)C₆H₄CCSiMe₃)(PiPr₃)₂] (4). From 2 and 3 in the molar ratio of 2:1, the dinuclear compound trans,trans-[(PiPr₃)₂ClIr(CC(SiMe₃)C₆H₄C(SiMe₃)C)IrCl(PiPr₃)₂] (5) was obtained. Reaction of 4 with [RhCl(PiPr₃)₂]₂ (6) at room temperature afforded the heterodinuclear alkyne(vinylidene) complex trans,trans-[(PiPr₃)₂ClIr(CC(SiMe₃)C₆H₄CCSiMe₃)RhCl(PiPr₃)₂] (7), which on heating at 45 °C was converted to the bis(vinylidene) isomer trans,trans-[(PiPr₃)₂ClIr(CC(SiMe₃)C₆H₄C(SiMe₃)C)RhCl(PiPr₃)₂] (8).     

[S2], [S3], and [N3] coordination modes of hydrotris(thioxotriazolyl)borato. Zinc, nickel, cobalt, and bismuth complexes

The ligand hydrotris(1,4-dihydro-3-methyl-4-phenyl-5-thioxo-1,2,4-triazolyl)borato (Tr^Ph,Me) was synthetized as natrium salt and the complexes [Zn(Tr^Ph,Me)₂] · 7.5H₂O · 1.5CH₃CN (2a), [Zn(Tr^Ph,Me)₂] · 8DMF (2b), [Co(Tr^Ph,Me)₂] · 8DMF (3a), [Ni(Tr^Ph,Me)₂] · H₂O · 6DMSO (4a), [Bi(Tr^Ph,Me)₂]NO₃ (5), have been isolated and structurally characterized by X-ray diffraction. In the zinc derivatives the ligand adopts different denticity and coordination modes, η² and [S₂] for 2a and η³ and [N₃] for 2b, depending on the crystallization solvent, giving rise to tetrahedral and octahedral geometry, respectively. In the octahedral cobalt and nickel complexes the ligand is η³ and [N₃] coordinated whereas in the bismuth complex the η³ and [S₃] coordination is exhibited.     

Synthesis and structural characterization of trans-[Mo2(H2DMepyF)2(CH3CN)4](BF4)6 (HDMepyF=N,N-di(6-methyl-2-pyridyl)formamidine)

Reaction of Mo₂(O₂CCH₃)₂(DMepyF)₂ (HDMepyF=N,N^′-di(6-methyl-2-pyridyl)formamidine) with HBF₄ in CH₂Cl₂/CH₃CN afforded the complex trans-[Mo₂(H₂DMepyF)₂(CH₃CN)₄](BF₄)₆ (1), which crystallized in two forms, trans-[Mo₂(H₂DMepyF)₂(CH₃CN)₄](ax-CH₃CN)₂(BF ₄)₆ · 2CH₃CN (1a), and trans- [Mo₂(H₂DMepyF)₂(CH₃CN)₄](ax-BF₄) ₂(BF₄)₄ · 2CH₃CN (1b). The molecular structures of complexes (1) consist of two quadruply bonded molybdenum atoms, which are spanned by two trans-bridging formamidinate ligands and coordinated by four trans-CH₃CN. Each H₂DMepyF⁺ ligand adopts an s-cis,s-cis- conformation. The difference between 1a and 1b is that complex 1a contains two CH₃CN molecules as axial ligands, while 1b contains two BF₄⁻ anions as axial ligands. Complex 1 is the first dimolybdenum complex containing a pair of trans bridging ligands and two pairs of trans-CH₃CN ligands.     

Synthetic and mechanistic studies on ruthenium dicarbonyl complexes containing PhP(CH2CH2CH2PCy2)2 (Cyttp) ligand

A synthetic and mechanistic study is reported on ligand substitution and other reactions of six-coordinate ruthenium(II) carbonyl complexes containing tridentate PhP(CH₂CH₂CH₂PCy₂)₂ (Cyttp). Carbonylation of cis-mer-Ru(OSO₂CF₃)₂(CO)(Cyttp) (1) affords [cis-mer-Ru(OSO₂CF₃)(CO)₂(Cyttp)]O₃SCF₃ (2(O₃SCF₃)) and, on longer reaction times, [cis-mer-Ru(solvent)(CO)₂(Cyttp)](O₃SCF₃)₂ (solvent = acetone, THF, methanol). 2(O₃SCF₃) reacts with each of NaF, LiCl, LiBr, NaI, and LiHBEt₃ to yield [cis-mer-RuX(CO)₂(Cyttp)]⁺ (X = F (3), Cl (4), Br (5), I (6), H (7)), isolated as 3-7(BPh₄). These conversions proceed with high stereospecificity to afford only a single isomer of the product that is assigned a structure in which the Ph group of Cyttp points toward the CO trans to X (anti when X = F, Cl, Br, or I; syn when X = H). Treatment of 2(O₃SCF₃) with NaOMe and CO generates the methoxycarbonyl complex [cis-mer-Ru(CO₂Me)(CO)₂(Cyttp)]⁺ (8), whereas addition of excess n-BuLi to 2(O₃SCF₃) in THF under CO affords mer-Ru(CO)₂(Cyttp) (9). The two ¹³C isotopomers [cis-mer-Ru(OSO₂CF₃)(CO)(¹³CO)(Cyttp)]O₃SCF₃ (2′(O₃SCF₃): ¹³CO trans to P_C; 2″(O₃SCF₃): ¹³CO cis to all P donors) were synthesized by appropriate adaptations of known transformations and used in mechanistic studies of reactions with each of LiHBEt₃, NaOMe/CO, and n-BuLi. Whereas LiHBEt₃ reacts with 2′(O₃SCF₃) and 2″(O₃SCF₃) to replace triflate by hydride without any scrambling of the carbonyl ligands, the corresponding reactions of NaOMe-CO are more complex. The methoxide combines with the CO cis to triflate in 2, and the resultant methoxycarbonyl ligand ends up positioned trans to the incoming CO in 8. A mechanism is proposed for this transformation. Finally, treatment of either 2′(O₃SCF₃) or 2″(O₃SCF₃) with an excess of n-BuLi leads to the formation of the same two ruthenium(0) isomers of mer-Ru(CO)(¹³CO)(Cyttp). These products represent, to our knowledge, the first example of a syn-anti pair of isomers of a five-coordinate metal complex.     

ansa-Chromocenes: An alternative route to Me2Si(C5Me4)2Cr

The mechanism for the preparation of Me₂Si(C₅Me₄)₂Cr, 1, from CrCl₂(THF)_x and Me₂Si(C₅Me₄)₂Li₂ was investigated and - in contrast to earlier claims - no evidence was found for the participation of an auxiliary ligand. The formation and stability of 1 is attributed to the combination of correct reaction conditions and a highly substituted ligand framework. Reactions with other ligands under identical conditions did not lead to the formation of ansa-chromocenes. Reaction with H₄C₂Ind₂Li₂ afforded the η³-Ind bridged dimer {H₄C₂(η⁵-Ind)(μ-,η³-Ind)Cr}₂, 9. Complex 1 does not coordinate PPh₃ or carbenes, but from reaction with two equivalents of xylyl isocyanide the CH-activated complex Me₂Si(C₅Me₄)(η³-C₅Me₃(H)(CH₂)Cr(CNC₆MeH₃)₂, 7, was obtained. Complexes 7 and 9 were characterised by X-ray crystallography.     

Analysis of the main structural trends for biscyclometalated dinuclear rhodium compounds of general formula Rh2(O2CR)2(PC)2 · 2H2O

A new series of biscyclometalated dinuclear rhodium (II) compounds with the general formula Rh₂(O₂CR)₂(PC)₂ · 2H₂O, being PC = (C₆H₄)P(C₆H₅)₂, R = CH₃ (1 · 2H₂O), PC = [(p-CH₃ OC₆H₃)P(p-CH₃ OC₆H₄)₂], R = CF₃ (2 · 2H₂O), PC = (C₆H₄)P[CH(CH₃)₂]₂, R = CH₃ (3 · 2H₂O) and PC = (C₆H₄)P(C₆H₅)₂, R = C₆F₅ (4 · 2H₂O) has been obtained. The crystal structures for these compounds have been determined by X-ray diffraction and the main structural trends, bond lengths, bond angles and torsion angles have been analyzed, and have also been compared with the structural parameters for different analogous complexes described previously in the literature.     

Versatile coordination behaviour of Ph2AsCH2AsPh2 with Ru(II)

Treatment of ‘RuCl₃ · 3H₂O’ with Ph₂AsCH₂AsPh₂ (dpam) in hot EtOH gives either trans-[RuCl₂(dpam-As,As′)(dpam-As)₂] (1), or cis-[RuCl₂(dpam-As,As′)₂] (2), depending on the mole ratio. On exposure to light, solutions of 2 isomerise to trans-[RuCl₂(dpam-As,As′)₂] (3). Treatment of [RuCl₂(PPh₃)₃] with two equivalents of dpam in CH₂Cl₂ gave a mixture of two products, from which trans-[RuCl₂(PPh₃) (dpam-As,As′)(dpam-As)] (4) was isolated by recrystallisation. The crystal structures of 1-4 are reported. Complexes 1-3 in CH₂Cl₂ undergo electrochemical oxidation to Ru(III), and the Ru(III) form of 2 undergoes isomerisation on the voltammetric timescale to the Ru(III) form of 3.     

Hydrogen-halide versus alkyl-halide oxidative addition in dimethyl platinum(II) complexes: Crystal structure of [PtBr2(bpy)]

Dimethyl platinum(II) complexes [PtMe₂(NN)] {NN = bu₂bpy (4,4′-di-tert-butyl-2,2′-bipyridine) (1a), bpy (2,2′-bipyridine) (1b), phen (1,10-phenanthroline) (1c)} reacted with commercial 3-bromo-1-propanol in the presence of 1,3-propylene oxide to afford cis, trans- [PtBrMe₂{(CH₂)₃OH}(NN)] (NN = bu₂bpy (2a), bpy (2b), phen (2c)). On the other hand, [PtMe₂(NN)] (1a)-(1b) reacted with the trace of HBr in commercial 3-bromo-1-propanol to give [PtBr₂(NN)] (NN = bu₂bpy (3a), bpy (3b)). The reaction pathways were monitored by ¹H NMR at various temperatures. Treatment of 1a-1b with a large excess of 3-bromo-1-propanol at −80 °C gave the corresponding methyl(hydrido)platinum(IV) complexes [PtBr(H)Me₂(NN)] (NN = bu₂bpy (4a), bpy (4b)) via the oxidative addition of dimethyl platinum(II) complexes with HBr. The complexes [PtBr(H)Me₂(NN)] decomposed by reductive elimination of methane above −20 °C for bu₂bpy and from −20 to 0 °C for bpy analogue to give methane and platinum(II) complexes [PtBrMe(NN)] (5a)-(5b) and then decomposed at about 0 °C to yield [PtBr₂(NN)] and methane. When the reactions were performed at a molar ratio of Pt:RX/1:10, the corresponding complexes [PtBrMe(NN)] (5a)-(5b) were also obtained. The crystal structure of the complex 3b shows that platinum adopts square planar geometry with a twofold axis through the platinum atom. The Pt…Pt distance (5.164 Å) is considerably larger than the interplanar spacing (3.400 Å) and there is no platinum-platinum interaction.     

Substitution reactions of tetrahydrofuran in [Cr(thf)3Cl3] with mono and bidentate N-donor ligands: X-ray crystal structures of [Cr(bipy)(OH2)Cl3] and [HpyNH2][Cr(bipy)Cl4]

Substitution of thf ligands in [Cr(thf)₃Cl₃] and [Cr(thf)₂(OH₂)Cl₃] was investigated. 2,2′-Bipyridine (bipy) was reacted with [Cr(thf)₃Cl₃] to form [Cr(bipy)(thf)Cl₃] (1), which was subsequently reacted with water to give [Cr(bipy)(OH₂)Cl₃] (2). Reaction of 1 with acetonitrile (CH₃CN), pyridine (py) and pyridine derivatives to form [Cr(bipy)(L)Cl₃] (L = CH₃CN 3, py 4 and 4-pyR with R = NH₂5, Bu^t6 and Ph 7). In addition, the substitution of bipy in [Cr(thf)₃Cl₃] was followed by ¹H NMR spectroscopy at room temperature, which showed completion of the reaction in ca. 100 min. Complex 2 was characterised by single crystal X-ray diffraction. The theoretical powder diffraction pattern of 2 was compared to the experimentally obtained powder X-ray diffraction pattern, and shows excellent agreement. The dimer [Cr₂(bipy)₂Cl₄(μ-Cl)₂] was cleaved asymmetrically to give the anionic complex [Cr(bipy)Cl₄]⁻ (8) and [Cr(bipy)₂Cl₂]⁺ (9). Complexes 8 and 9 were characterised by single crystal X-ray diffraction.     

Syntheses, structures and electrochemical study of π-acetylene complexes of cobalt

The preparation and characterisation of the complexes [Co₂(CO)₄(PMe₃)₂][Co₂(CO)₆](Me₃SiC₂C₂SiMe₃) (4), [Co₂(CO)₄(dppm)][Co₂(CO)₆](Me₃SiC₂C₂H) (5), [Co₂(CO)₄(dppa)][Co₂(CO)₆](Me₃SiC₂C₂SiMe₃) (6), [Co₂(CO)₄(dppm)]₂[Co₂(CO)₆](Me₃SiC₂CCC₂C₂SiMe₃) (7) and [{SiMe₃(Co₂(CO)₄(dppm))C₂}₂(HCC)(1,3,5-C₆H₃)] (8) are described. An electrochemical study of the complexes 5-8 and of the related [Co₂(CO)₄(dppm)]₂(Me₃SiC₂(CC)₂C₂SiMe₃) (1), [Co₂(CO)₄(dppa)]₂(Me₃SiC₂C₂SiMe₃) (2) and [{SiMe₃(Co₂(CO)₄(dppm))C₂}(HCC)₂(1,3,5-C₆H₃)] (3) is presented by means of the cyclic and square-wave voltammetry techniques. Crystals of 8 suitable for single-crystal X-ray diffraction were grown and the molecular structure of this compound is discussed.     

Heterobimetallic Fe-Pd and Fe-Pt NCN pincer complexes (NCN = [C6H2(CH2NMe2)2-2,6])

The meta-diaminoaryl ferrocenes Fc-NCN-H (3) and Fc-CC-NCN-H (5) (Fc = (η⁵-C₅H₅)(η⁵-C₅H₄)Fe, NCN-H = C₆H₃(CH₂NMe₂)₂-3,5) can be used as precursors in the preparation of heterobimetallic transition metal complexes of structural type Fc-NCN-MX (NCN = [C₆H₂(CH₂NMe₂)₂-2,6]⁻; MX = PdCl (7), PtCl (8), PtI (9)) and Fc-CC-NCN-MX (MX = PdCl (11), PdI (12), PtCl (13)), respectively. They are accessible by applying different synthesis procedures, including oxidative addition and metallation-transmetallation processes.Cyclovoltammetric studies show that the ferrocene moieties in 3, 5, 7-9 and 11-13 can reversibly be oxidised. The potential of the Fe(II)/Fe(III) redox couple decreases with increasing electron density at the NCN pincer unit. The use of 8 as a possible (electro)chemical sensor in the detection of SO₂ is discussed as well.The solid-state structures of 8 and 13 are reported. The crystals of 8 contain two molecules of 8 in the asymmetric unit. The plane of the C₆H₂ moiety is with 27.2(3)° and 38.2(3)° tilted towards the C₅H₄ entity, while in 13 an angle of 45.9(3)° can be found. The d⁸-electron configured platinum atoms possess a somewhat distorted square-planar surrounding, setup by two Me₂NCH₂ortho-substituents, the NCN C_ipso carbon atom and the chloride ligand.     

Reactivity of the ligand bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]ether (L1) with Pd(II) and Pt(II): crystal structure of cis-[PtCl2(L1)]

The coordination chemistry of the ligand bis[2-(3,5-dimethyl-1-pyrazolyl)ethyl]ether (L₁) was tested in front of Pd(II) and Pt(II). Complexes cis-[MCl₂(L₁)] (M=Pd(II) and Pt(II)) were obtained, due to the chelate condition of the ligand and the formation of a stable 10-membered ring. The crystal structure of cis-[PtCl₂(L₁)] was resolved by X-ray diffraction. Treatment of [PdCl₂(L₁)] or [Pd(CH₃CN)₄](BF₄)₂ with AgBF₄ in the presence of L₁ gave the complex [Pd(L₁)₂](BF₄)₂. The initial cis-[PdCl₂(L₁)] was recovered by reacting [Pd(L₁)₂](BF₄)₂ with an excess of NEt₄Cl. Reaction of [Pt(CH₃CN)₄](BF₄)₂ (generated in situ from [PtCl₂(CH₃CN)₂] and AgBF₄ in acetonitrile) with ligand L₁ yields complex [Pt(L₁)₂](BF₄)₂.     

Secondary ligand-metal interactions in rhodium(III) and iridium(III) phosphoramidite complexes

The synthesis, characterization, and application in asymmetric catalytic cyclopropanation of Rh(III) and Ir(III) complexes containing (S_a,R_C,R_C)-O,O′-[1,1′-binaphthyl-2,2′-diyl]-N,N′-bis[1-phenyl-ethyl]phosphoramidite (1) are reported. The X-ray structures of the half-sandwich complexes [MCl₂(C₅Me₅)(1,κP)] (M = Rh, 2a; M = Ir, 2b) show that the metal-phosphoramidite bond is significantly shorter in the Ir(III) analog. Chloride abstraction from 2a (with CF₃SO₃SiMe₃ or with CF₃SO₃Me) and from 2b (with AgSbF₆) gives the cationic species [MCl(C₅Me₅)(1,2-η-1,κP)]⁺ (M = Rh, 3a; M = Ir, 3b), which display a secondary interaction between the metal and a dangling phenethyl group (NCH(CH₃)Ph) of the phosphoramidite ligand, as indicated by NMR spectroscopic studies. Complexes 3a and 3b slowly decompose in solution. In the case of 3b, the binuclear species [Ir₂Cl₃(C₅Me₅)₂]⁺ is slowly formed, as indicated by an X-ray study. Preliminary catalytic tests showed that 3a cyclopropanates styrene with moderate yield (35%) and diastereoselectivity (70:30 trans:cis ratio) and with 32% ee (for the trans isomer).     

Electrochemical behavior of S,S-bridged adducts of square planar metalladithiolene complexes [M(S2C2Ph2)2](M=Ni, Pd, and Pt)

The electrochemical behavior of the S,S^′-bridged adducts of square planar metalladithiolene complexes was investigated by using cyclic voltammetry and electrochemical spectroscopies (visible, near-IR, and ESR). The norbornene-bridged S,S^′-adduct [Ni(S₂C₂Ph₂)₂(C₇H₈)] (2a; C₇H₈=norbornene) formed by [Ni(S₂C₂Ph₂)₂] (1a) and quadricyclane (Q) was dissociated by an electrochemical reduction, and anion 1a⁻ and norbornadiene (NBD) were formed. Q was isomerized to NBD in the overall reaction. The o-xylyl-bridged S,S^′-adduct [Ni(S₂C₂Ph₂)₂(CH₂)₂(C₆H₄)] (3a; (CH₂)₂(C₆H₄)=o-xylyl) was also dissociated by an electrochemical reduction, and this reaction gave the o-xylyl radical (o-quinodimethane). The reduction of complex 3a in the presence of excess o-xylylene dibromide underwent the catalytic formation of o-quinodimethane. The butylene-bridged S,S^′-adduct [Ni(S₂C₂Ph₂)₂(CH₂)₄] (4a; (CH₂)₄=butylene) was stable on an electrochemical reduction. The lifetimes of reduced species of these adducts 2a-4a were influenced by the stability of the eliminated group (stability: NBD > o-xylyl radical (o-quinodimethane) > butylene radical). Therefore, the reduced species are stable in the sequence 4a⁻ > 3a⁻ > 2a⁻. Although the palladium complex [Pd(S₂C₂Ph₂)₂] (1b) was easier to reduce than the nickel complex 1a or the platinum complex [Pt(S₂C₂Ph₂)₂] (1c), their S,S^′-adducts were easier to reduce in the order of Ni adduct > Pd adduct > Pt adduct.     

Synthesis and structures of bimetallic silicon-containing imido alkylidene complexes of molybdenum Me2Si[CHMo(NAr)(ORF3)2]2 and PhVinSi[CHMo(NAr)(ORF3)2]2

Bimetallic alkylidene complexes of molybdenum (R_F3O)₂(ArN)MoCH-SiMe₂-CHMo(NAr)(OR_F3)₂ (1) and (R_F3O)₂(ArN)MoCH-SiPhVin-CHMo(NAr)(OR_F3)₂ (2) (Ar = 2,6-C₆H₃; R_F3 = CMe₂CF₃) have been prepared by the reactions of vinyl silicon reagents Me₂Si(CHCH₂)₂ and PhSi(CHCH₂)₃ with known alkylidene compound PhMe₂C-CHMo(NAr)(OR_F3)₂. Complexes 1 and 2 were structurally characterized. Ring opening metathesis polymerization (ROMP) of cyclooctene using compounds 1 and 2 as initiators led to the formation of high molecular weight polyoctenamers with predominant trans-units content in the case of 1 and predominant cis-units content in the case of 2.     

Synthesis and structures of aryloxo- and binaphthoxogermanium(IV) alkyl iodide complexes

The germanium(II) aryloxide complexes (S)-[Ge{O₂C₂₀H₁₀-(SiMe₂Ph)₂-3,3′}{NH₃}] (1) and [Ge(OC₆H₃Ph₂-2,6)₂] (2) react with either Bu^tI or MeI to yield the corresponding germanium(IV) compounds (S)-[Ge{O₂C₂₀H₁₀-(SiMe₂Ph)₂-3,3′}{Bu^t}{I}] (3), (S)-[Ge{O₂C₂₀H₁₀-(SiMe₂Ph)₂-3,3′}{Me}{I}] (4), [Ge(OC₆H₃Ph₂-2,6)₂(Bu^t)(I)] (5), and [Ge(OC₆H₃Ph₂-2,6)₂(Me)(I)] (6). Compound 6 reacts with 2,6-diphenylphenol to yield [Ge(OC₆H₃Ph₂-2,6)₃(Me)] (7), while 3-5 do not. The X-ray crystal structures of 3-5 and 7 were determined, and 3-5 represent the first structurally characterized germanium(IV) species having germanium bound to both oxygen and iodine.     

Unexpected formation and structure elucidation of mer-[RuCl3(TMSO)(bpy)] derived from [H(TMSO)][trans-RuCl4(TMSO)2] under mild condition

Treatment of [H(TMSO)][trans-RuCl₄(TMSO)₂] (1) with 2,2′-bipyridine (bpy) in ethanol at room temperature resulted an unknown mer-[RuCl₃(TMSO)(bpy)] (3) and a known cis-[RuCl₂(TMSO)₄] (4) (TMSO =  tetramethylene sulfoxide) complexes. The 3 was obtained by the substitution with bpy in mer-[RuCl₃(TMSO)₃] (2), whereas 4 was obtained by one-electron reduction of 2, suggesting that 2 is a precursor for both 3 and 4. The structure of 3 was determined by single crystal X-ray diffraction. The reaction is a new synthetic procedure for 3 and/or 3 and 4 in mild reaction conditions from the anionic complex 1. It involves simultaneous substitution and redox reaction. This is the first known example of precisely characterized Ru(III)-chloride-TMSO-bpy-complex derived from anionic [H(TMSO)][trans-RuCl₄(TMSO)₂] at room temperature.     

New aryl phosphinite ligands avoiding ortho-metallation: Synthesis and molecular structures of trans-[PdCl2(PPh2OR)2] and trans-[Rh(CO)Cl(PPh2OR)2] (R = 2,4,6-Me3C6H2; 2,6-Ph2C6H3)

The new aryl phosphinites PPh₂OR (R = 2,4,6-Me₃C₆H₂, 1; R = 2,6-Ph₂C₆H₃, 2) have been prepared from chlorodiphenylphosphine and the corresponding phenols. In these ligands, the ortho-positions of the aromatic phosphite function are blocked by methyl and phenyl substituents, which allows coordination to metal centres without ortho-metallation. Thus, reaction with [PdCl₂(cod)] leads to the complexes trans-[PdCl₂(PPh₂OR)₂] (R = 2,4,6-Me₃C₆H₂, 3; R = 2,6-Ph₂C₆H₃, 4), while the reaction with [Rh₂(CO)₄Cl₂] gives trans-[Rh(CO)Cl(PPh₂OR)₂] (R = 2,4,6-Me₃C₆H₂, 5; R = 2,6-Ph₂C₆H₃, 6). The single-crystal X-ray structure analyses of 3 and 5 confirm the trans-coordination of the new ligands in these square-planar complexes.