Synthesis and structure of (boratabenzene)rhodacarborane (η-7,8-C2B9H11)Rh(η-C5H5BMe)

The bromide complex [(η-C₅H₅BMe)RhBr₂]₂ (1) was synthesized by the reaction of the cyclooctadiene derivative (η-C₅H₅BMe)Rh(1,5-C₈H₁₂) with Br₂. The reaction of compound 1 with Tl[Tl(η-7,8-C₂B₉H₁₁)] gave (boratabenzene)rhodacarborane (η-7,8-C₂B₉H₁₁)Rh-(η-C₅H₅BMe) (2). The structure of compound 2 was determined by X-ray diffraction     

Synthesis and crystal structure of [(η3-C3H5)(CO)2Mo(μ-S2CPCy3)-Mo(η3-CH2CMeCH2)(CO)2]

A novel dimolybdenum complex [(³-C₃H₅)(CO)₂Mo(-S₂CPCy₃)Mo(³-CH₂CMeCH₂)(CO)₂], obtained by reacting the [(CO)₂(³-C₃H₅)Mo(-S₂CPCy₃)Mo(CO)₃]^– anion with an excess of ClCH₂CMe=CH₂, has been characterized by i.r., ³¹P{¹H}, ¹H- and ¹³C-n.m.r. spectroscopy and by elemental analysis. The crystal structure of the complex, determined by X-ray diffraction, shows a definite preference for the central carbon of the S₂CPCy₃ bridge to bind to the Mo(2) atom coordinated by ³-2-methylallyl, rather than the Mo(1) atom attached to unsubstituted ³-allyl ligand.     

Correlations between 13C NMR chemical shifts of [(1-R-η3-C3H4)PdCl]2 and Na[(1-R-η3-C3H4)PdCl2] and substituent constants

Linear correlations between ¹³C NMR chemical shifts of unsubstituted terminal carbon atom of the allylic ligand in [(1-R-η³-C₃H₄)PdCl]₂ and Na[(1-R-η³-C₃H₄)PdCl₂] and the modified Hammett constants were established. Two-parameter correlations using the Swain-Lupton parameters R ⁺, R ⁻, and F were obtained. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1171–1174, June, 2008.     

Photochemical arene exchange in the iron dicarbollide complex [(η-9-SMe2-7,8-C2B9H10)Fe(η-C6H6)]+

Visible light irradiation of the dicarbollide complex [(η-9-SMe₂-7,8-C₂B₉H₁₀)Fe(η-C₆H₆)]⁺ (2a) in the presence of the benzene derivatives in CH₂Cl₂/MeNO₂ resulted in cations [(η-9-SMe₂-7,8-C₂B₉H₁₀)Fe(η-C₆R₆)]⁺ (2b-g; arene is anisole (b), toluene (c), m-xylene (d), mesitylene (e), durene (f), and hexamethylbenzene (g)) due to the arene exchange. The structures of [2g]PF₆ and related tricarbollide complex [(η-1-Bu^tNH-1,7,9-C₃B₈H₁₀)Fe-(η-C₆H₆)]PF₆ (1) were confirmed by X-ray diffraction analysis. The nature of bonding in cations 1, 2a, and [CpFe(η-C₆H₆)]⁺ was analyzed by an energy decomposition analysis.     

Synthesis and characterisation of a pyrazine bridged bis-allyl ruthenium(IV) complex. Crystal structure of [{(η3:η3-C10H16)RuCl2}2(μ-C4H4N2)]·2CHCl3

The reaction of pyrazine with the ruthenium(IV) bis-allyl dimer [(η³:η³-C₁₀H₁₆)RuCl(μ-Cl)]₂ gives the bridged binuclear complex [{(η³:η³-C₁₀H₁₆)RuCl₂}₂(μ-C₄H₄N₂)] in high yield. The complex has been characterised by ¹H NMR spectroscopy and by a single-crystal X-ray diffraction study.     

The Thermolysis of [Ru3(CO)12] in Cyclohexene: Synthesis and Charaterisation of the New Clusters [Ru3H2(CO)9(μ3-η1:η2:η1-C6H8)] and [Ru5(CO)12(μ4-η2-C6H8)(η4-C6H8)]

Thermolysis of [Ru₃(CO)₁₂] in cyclohexene for 24 h affords the complexes [Ru(CO)₃(η⁴-C₆H₈)] (1), [Ru₃H₂(CO)₉(μ₂-η¹:η²:η¹-C₆H₈)] (2), [Ru₄(CO)₁₂(μ₄-C₆H₈)] (3) [Ru₄(CO)₉(μ₄-C₆H₈)(η⁶-C₆H₆)] (4a and 4b, two isomers) and [Ru₅(CO)₁₂(μ₄-η²-C₆H₈)(η⁴-C₆H₈)] (5), where 1, 3, 4a and 4b have been previously characterised as products of the thermolysis of [Ru₃(CO)₁₂] with cyclohexa-1,3-diene. The molecular structures of the new clusters 2 and 5 were determined by single-crystal X-ray crystallography, showing that two conformational polymorphs of 5 exist in the solid state, differing in the orientation of the cyclohexa-1,3-diene ligand on a ruthenium vertex.     

Synthesis and structure of neutral π-arene complex (η6-C6H5Me)U(AlCl4)3

A new neutral -arene complex of trivalent uranium, (⁶-C₆H₅Me)U(AlCl₄)₃ (1), was obtained by the reductive Freidel-Crafts reaction. The crystal structure of 1 was determined by single crystal X-ray diffraction analysis. The U atom in 1 is bound to the C₆H₅Me group by the ⁶ mechanism and is linked to the three AICl₄ groups through two g-CI bridges. The coordination of the U atom is a distorted pentagonal bipyramid in which the center of the arene ring is in one apical position, and the bridging Cl atoms occupy the other vertices.Translated from Izvestiva Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 469–472, February, 1996.     

Cyclooctaselenadiazole: synthesis,decomposition pathway,and reaction with (η5-C5H5) Co(L)2 (L = C2H4, PPh3). Crystal and molecular structure of [(η5-C5H5)CO]2(μ2-η3,η2-C8H6Se)

Thermolysis of cyclooctaselenadiazole (2) yields only selenium-containing products. Compound 2 reacts with CpCo sources to give [(η⁵-C₅H₅)CO]₂(μ₂η³,η²-C₈H₆Se), a fluxional compound whose structure has been determined by X-Ray crystallography.     

Lithium and lanthanum complexes with acenaphthylene dianion. Molecular structure of [Li(Et2O)2]2μ2:η3[Li(η3:η3-C12H8)]2 complex

The lithium complex with the acenaphthylene dianion [Li(Et₂O)₂]₂₂:³[Li(³:³-C₁₂H₈)]₂ (1) was synthesized by the reduction of acenaphthylene with lithium in diethyl ether. According to the X-ray diffraction data, compound 1 has a reverse-sandwich structure with the bridging dianion ₂:³[Li(³:³-C₁₂H₈)]₂. Two lithium atoms in complex 1 are located between two coplanar acenaphthylene ligands of the ₂:³[Li(³:³-C₁₂H₈)]₂ ^2– dianion and are ³-coordinated with the five- and six-membered rings. The lanthanum complex with the acenaphthylene dianion [LaI₂(THF)₃]₂(₂-C₁₂H₈) (2) was synthesized by the reduction of acenaphthylene in THF with the lanthanum(iii) complex [LaI₂(THF)₃]₂(₂-C₁₀H₈) containing the naphthalene dianion. The ¹H NMR spectrum of complex 2 in THF-d₈ exhibits four signals of the acenaphthylene dianion, whose strong upfield shifts compared to those of free acenaphthylene indicate the dianionic character of the ligand. The highest upfield chemical shift belongs to the proton bound to the C atom on which, according to calculation, the maximum negative charge is concentrated.     

Synthesis and crystal structure of (E)-[(2-cyclohexenyl) vinyl]triaryltin

(E)-[(2-Cyclohexenyl)vinyl]triaryltin (aryl=phenyl, p-tolyl) were synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy. The crystal structure of (E)-[(2-cyclohexenyl)vinyl]triphenyltin was also determined by the X-ray diffraction. Experiments show that this compound has the conjugated system, which makes it have possible bioactivity and anti-tumor activity.     

Conformational analysis and x-ray crystal structure of [(η5-C5H5)Fe(CO)(PPh3)CH2CH3]

The complex [(η⁵-C₅H₅)Fe(CO)(PPh₃)CH₂CH₃] is shown by ¹H NMR spectroscopy and an X-ray crystal structure analysis to adopt a single conformation with the methyl group residing between the cyclopentadienyl and carbon monoxide ligands.     

Syntheses of chromium tricarbonyl organometals of 1-methyl-naphthalene and different polycyclic aromatic hydrocarbons,characterisation of the (C11H10)Cr(CO)3 isomers and the crystal structure of the [(η6-5,6,7,8,9,10-C11H10)Cr(CO)3] complex

The synthesis of organometal complexes from chromium hexacarbonyl with 1-methyl-naphthalene ligand is reported. Two arene-chromium-tricarbonyl isomers are formed at competitive yields, featured with the metal fragment coordinated to both the methylated and the benzenic aromatic ring. A single-crystal X-ray diffraction measurement has been performed on the [(η⁶-5,6,7,8,9,10-C₁₁H₁₀)Cr(CO)₃] isomer, which presents the metal carbonyl moiety attached to the benzenic arene ligand. The products of reaction have been studied by UV–VIS–NIR, fluorescence and ¹H NMR spectroscopies. A detailed vibrational characterisation by mean of experimental FT-IR and Raman spectroscopy and DFT calculations is reported. The electron ligand donation to the metal carbonyl system, determined by FT-IR spectroscopy, has been related to the actual decrease of resonance energy of the aromatic hydrocarbon in the complex and compared with other chromium tricarbonyl complexes of different polycyclic aromatic hydrocarbons provided with the naphthalenic moiety.     

Uranium versus Thorium: Synthesis and Reactivity of [η5-1,2,4-(Me3C)3C5H2]2U[η2-C2Ph2]

The synthesis, electronic structure, and reactivity of a uranium metallacyclopropene were comprehensively studied. Addition of diphenylacetylene (PhC≡CPh) to the uranium phosphinidene metallocene [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂U=P-2,4,6-tBu₃C₆H₂ ( 1 ) yields the stable uranium metallacyclopropene, [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂U[η²-C₂Ph₂] ( 2 ). Based on density functional theory (DFT) results the 5f orbital contributions to the bonding within the metallacyclopropene U-(η²-C=C) moiety increases significantly compared to the related Th^IV compound [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂Th[η²-C₂Ph₂], which also results in more covalent bonds between the [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂U²⁺ and [η²-C₂Ph₂]²⁻ fragments. Although the thorium and uranium complexes are structurally closely related, different reaction patterns are therefore observed. For example, 2 reacts as a masked synthon for the low-valent uranium(II) metallocene [η⁵-1,2,4-(Me₃C)₃C₅H₂]₂U^II when reacted with Ph₂E₂ (E=S, Se), alkynes and a variety of hetero-unsaturated molecules such as imines, ketazine, bipy, nitriles, organic azides, and azo derivatives. In contrast, five-membered metallaheterocycles are accessible when 2 is treated with isothiocyanate, aldehydes, and ketones.     

The reductive dimerization of [W(NCMe)(MeC2Me)2(η-C5H5)]+: Synthesis and X-ray structure of the novel bis(metallacyclopentadiene) complex [W2(μ-σ,σ,η2,η2-C4Me4)2(η-C5H5)2]

Treatment of [W(CO)(MeC₂Me)₂(-C₅H₅)][PF₆] with ONMe₃ in acetonitrile yields [W(NCMe)(MeC₂Me)₂(-C₅H₅)][PF₆] which undergoes irreversible reduction at a Pt electrode in THF. Sodium amalgam reduction of [W(NCMe) (MeC₂Me)₂(-C₅H₅)][PF₆] gives orange crystals of [W₂(µ-,, ², ²-C₄Me₄)₂ (-C₅H₅)₂] X-ray studies on which reveal pairwise alkyne coupling and a novel bis(metallacyclopentadiene) structure.Dedicated to Professor L. F. Dahl on the occasion of his 65th birthday.     

Synthesis and structures of the η5-C5H5Cl(CO)2W-η1,η5-(PPh2)C5H4(CO)2Fe-η1,η5-C5H4Mn(CO)3 and MeSi[C5H4(CO)2Fe-η1,η5-C5H4Mn(CO)2PPh3]3 complexes

The metallation of the η⁵-C₅H₅(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ complex with BuⁿLi (THF, ?78 °C) followed by the treatment of the lithium derivative with Ph₂PCl afforded the η⁵-Ph₂PC₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ complex. The reaction of the latter with η⁵-C₅H₅(CO)₃WCl in the presence of Me₃NO produced the trinuclear complex η⁵-C₅H₅Cl(CO)₂W-η¹,η⁵-(Ph₂P)C₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃. The structure of the latter complex was established by IR, UV, and 1H and ³¹P NMR spectroscopy and X-ray diffraction. The reaction of MeSiCl₃ with three equivalents of LiC₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₂PPh₃ gave the hexanuclear complex MeSi[C₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₂PPh₃]₃.     

Synthesis of the iridacarborane halide complexes [(η-9-SMe2-7,8-C2B9H10)IrX2]2 (X = Cl,Br, or I)

The reaction of Na[9-SMe₂-7,8-C₂B₉H₁₀] with [(Cod)IrCl]₂ (Cod is cycloocta-1,5-diene) gave rise to the iridium complex (-9-SMe₂-7,8-C₂B₉H₁₀)Ir(Cod). Treatment of the latter with anhydrous acids HX (X = Cl, Br, or I) afforded the corresponding iridacarborane halide complexes [(-9-SMe₂-7,8-C₂B₉H₁₀)IrX₂]₂ analogous to the cyclopentadienyl complexes [(C₅Me₅)IrX₂]₂.     

Molecular structure of ansa-compound (η5-C5H4)CMe2(η5-C9H6)TiCl2

The structure of a new ansa compound, (⁵-C₅H₄)CMe₂(⁵-C₉H₆)TiCl₂ (1), was studied by X-ray analysis:a = 15.00(1),b =15.500(5),c = 13.032(4) Å, = 92.66°(4),V = 3025.1(1) ų, space groupP2₁/.,R = 0.038. The distorted tetrahedral coordination sphere of the Ti atom is formed by two Cl atoms and two -ligands. It was proposed that the angle () between theC-M direction and the line normal to M-Cp can be considered as one of the geometric parameters characteristic of the structure-properties correlation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 305–308, February, 1995.     

Synthesis of rhodacarborane halide complexes [(η-9-Me2S-7,8-C2B9H10)RhX2]2 (X=Cl, Br, or I)

The reactions of the complex (η-9-Me₂S-7,8-C₂B₉H₁₀)Rh(η-cod) (cod is 1,5-cyclo-octadiene) with HX acids (X=Cl, Br, or I) in acetone afforded rhodacarborane halide complexes [(η-9-Me₂S-7,8-C₂B₉H₁₀)RhX₂]₂, which are carborane analogs of cyclopentadienyl halide rhodium complexes [(η-C₅R₅)RhX₂]₂. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1817–1819, September, 1999.     

Thorocene adducts of the neutral 2,2′-bipyridine and its radical anion. Synthesis and crystal structures of [Th(η8-C8H8)2(κ2-bipy)] and [Th(μ-η8:η5-C8H8)2(κ2-bipy)K(py)2]∞

Thorocene [Th(Cot)₂] (Cot = η⁸-C₈H₈) readily reacts with 2,2′-bipyridine to give [Th(Cot)₂(κ²-bipy)], which has an unusual bent geometry. This compound is rapidly reduced by KC₈ into the anionic derivative [(Th(Cot)₂(κ²-bipy)]⁻. X-ray diffraction studies suggest the latter to be a Th(IV) compound with the bipyridyl radical anion. These complexes are rare examples of bent actinocene [An(Cot)₂(L)]^q− (q = 0, 1; An = actinide) and bipyridine-containing thorium species.