Synthesis and structures of aluminum alkanethiolate complexes

The homoleptic aluminum thiolate complex [Al(mu-S-t-Bu)(S-t-Bu)(2)](2) was prepared by reacting AlBr(3) with NaS-t-Bu while the analogous 2-propanethiolate complex [Al(mu-S-i-Pr)(S-i-Pr)(2)](2) was synthesized by reacting AlH(3)(OEt(2)) with i-PrSH. In the solid state, the dimers have tetrahedral Al atoms and anti-Al(mu-SR)(2)Al four-member rings. The attempted synthesis of [Al(mu-S-t-Bu)(S-t-Bu)(2)](2) by reacting Al(N-i-Pr(2))(3) with t-BuSH in THF solvent yielded the thermally stable THF adduct Al(S-t-Bu)(3)(THF). The same reaction in diethyl ether solvent produced a mixture of [Al(mu-mgr;-S-t-Bu)(S-t-Bu)(2)](2) and the salt [i-Pr(2)NH(2)][Al(S-t-Bu)(4)]. In the solid-state structure of the salt, the anion [Al(S-t-Bu)(4)](-) has a distorted tetrahedral geometry. Reactions of [Al(NMe(2))(3)](2) and AlH(3)(NMe(2)Et) with the alkanethiols yielded stable amine adducts Al(SR)(3)(R'NMe(2)) (R = i-Pr or t-Bu; R' = H or Et). The ligand adducts Al(S-i-Pr)(3)(HNMe(2)) and Al(S-t-Bu)(3)(THF) have distorted trigonal pyramidal geometries in the solid state. Three of the new compounds, [Al(mu-S-i-Pr)(S-i-Pr)(2)](2) and Al(SR)(3)(HNMe(2)) (R = i-Pr or t-Bu), are viable precursor candidates for the chemical vapor deposition of aluminum sulfide films because they are thermally stable, volatile liquids at moderate temperatures.     

Synthesis of boroxine-linked aluminum complexes

The reaction of LAlH(2) (L = HC(CMeNAr)(2), Ar = 2,6-iPr(2)C(6)H(3)) (1) with 3-methylphenylboronic acid and 3-fluorophenylboronic acid resulted in the boroxine-linked aluminum compounds LAl[OB(3-CH(3)C(6)H(4))](2)(μ-O) (2) and LAl[OB(3-FC(6)H(4))](2)(μ-O) (3), respectively. LAl[OB(2-PhC(6)H(4))(OH)](2) (4) was synthesized by the reaction of 1 with 2-biphenylboronic acid. Compound 4 is the intermediate analogue to those, which we postulated for the formation of 2 and 3. The reaction of 1 with 3-hydroxyphenylboronic acid resulted in the first metal benzoboroxole oxide LAl[OB(o-CH(2)O)C(6)H(4)](2) (5), which is formed from a compound with B-(OH)(2) and C-OH functionalities.     

Synthesis and structures of gold perfluorophthalimido complexes

Compounds of the new tetrafluorophthalimido anion, [C(6)F(4)(CO)(2)N](-), are readily accessible by treatment of tetrafluorophthalimide with either LiNPr(i)(2) or mixtures of NEt(3) and Me(3)ECl (E = Si or Sn), to give C(6)F(4)(CO)(2)N-X (X = Li 3, SiMe(3)4, and SnMe(3)5). The reaction of the trimethylsilyl derivative 4 with AgF leads cleanly to the ion pair complex [Ag(NCMe)(2)][Ag(N(CO)(2)C(6)F(4))(2)] (6·2MeCN), which contains a linear [Ag{N(CO)(2)C(6)F(4)}(2)](-) anion and a tetracoordinate Ag(+) cation. Compound 6 reacts with iodine to give the N-iodo compound C(6)F(4)(CO)(2)NI 7, which crystallises as an acetonitrile adduct. Treatment of 6 with LAuCl affords LAu{N(CO)(2)C(6)F(4)} (L = Ph(3)P 8a, Cy(3)P 8b, or THT 9), whereas the reaction with AuCl in acetonitrile affords the heterobinuclear compound [Ag(MeCN)(2)][Au{N(CO)(2)C(6)F(4)}(2)]·MeCN (10·3MeCN). The tetrafluorophthalimido ligand is not readily displaced by donor ligands; however, the addition of B(C(6)F(5))(3)(Et(2)O) to a diethyl ether solution of 8a leads to the salt [Au(PPh(3))(2)][N{COB(C(6)F(5))(3)}(2)C(6)F(4))] 11. The analogous reaction of (THT)Au{N(CO)(2)C(6)F(4)} with B(C(6)F(5))(3) in toluene in the presence of excess norbornene (nb) gives [Au(nb)(3)][N{COB(C(6)F(5))(3)}(2)C(6)F(4))] 12. Compounds 11 and 12 contain a new non-coordinating phthalimido-bridged diborate anion with O-bonded boron atoms. The crystal structures of compounds 2-11 are reported.     

Synthesis and structures of cuprous triptycylthiolate complexes

A synthesis of 1-(thioacetyl)triptycene (5), a convenient protected form of 1-(thiolato)triptycene [STrip](-), is described, a key transformation being the high yield conversion of tert-butyl 1-triptycenyl sulfide (8) to 5 by a protocol employing BBr(3)/AcCl. Syntheses of the two-coordinate copper(I) compounds [Bu(4)N][Cu(STrip)(2)], [Bu(4)N]10, and [(Cu(IMes)(STrip)] (13) proceed readily by chloride displacement from CuCl and [Cu(IMes)Cl], respectively. Reaction of 10 with Ph(3)SiSH or Me(3)SiI produces the heteroleptic species [Cu(STrip)(SSiPh(3))](-) (11) and [Cu(STrip)I](-) (12), detected by mass spectrometry, in mixture with the homoleptic bis(thiolate) anions. Structural identification by X-ray crystallography of the ligand precursor molecules 9-(thioacetyl)anthracene (4, triclinic and orthorhombic polymorphs), tert-butyl 9-anthracenyl sulfide (7), 5, and tert-butyl 1-triptycenyl sulfide (8) are presented. Crystallographic characterization of bis(9-anthracenyl)sulfide (3), which features a C-S-C angle of 104.0° and twist angle of 54.8° between anthracenyl planes, is also given. A crystal structure of [Bu(4)N][(STrip)], [Bu(4)N]9, provides an experimental measure of 144.6° for the ligand cone angle. The crystal structures of [Bu(4)N]10 and 13 are reported, the former of which reveals an unexpectedly small C-S···S-C torsion angle of ～41° (average of two values), which confers a near "cis" disposition of the triptycenyl groups with respect the S-Cu-S axis. This conformation is governed by interligand π···π and CH···π interactions. A crystal structure of an adventitious product, [Bu(4)N][(Cu-STrip)(6)(μ(6)-Br)]·[Bu(4)N][PF(6)], [Bu(4)N]14·[Bu(4)N][PF(6)] is described, which reveals a cyclic hexameric structure previously unobserved in cuprous thiolate chemistry. The Cu(6)S(6) ring displays a centrosymmetric cyclohexane chair type conformation with a Br(-) ion residing at the inversion center and held in place by apparent soft-soft interactions with the Cu(I) ions.     

Synthesis and structures of fulvene-bridged diruthenium complexes

Three diruthenium carbonyl complexes, namely (η ³:η ⁵-C₅H₄C(CH₂)₂)Ru₂(CO)₅ (1), (η ³:η ⁵-C₅H₄C(CHCH₂)(C₂H₅))Ru₂(CO)₅ (2), and (η ¹:η ⁵-C₅H₄C₅H₈)Ru₂(CO)₆ (3), were obtained from the reactions of C₅H₄C(Me)₂, C₅H₄C(Et)₂, and C₅H₄C(CH₂)₄, respectively, with Ru₃(CO)₁₂ in refluxing xylene. The complexes were characterized by elemental analysis, IR and ¹H NMR spectra. Single-crystal X-ray diffraction analysis for complexes 1 and 2 revealed that the fulvene ligands bridge two ruthenium atoms in η ³:η ⁵ fashion.     

Synthesis and structures of zirconium amide-iodide complexes

Zirconium amide-iodide complexes were synthesized for possible use as chemical vapor deposition precursors to zirconium nitride films. The series of six complexes Zr(NR(2))(4-n)I(n)(R = Me or Et; n = 1-3) was prepared by reacting ZrI(4) and Zr(NR(2))(4) in hot toluene. X-ray crystallographic analyses were performed for Zr(NMe(2))(3)I, Zr(NEt(2))(2)I(2), and Zr(NEt(2))I(3). In the solid state, Zr(NMe(2))(3)I and Zr(NEt(2))(2)I(2) are the discrete dimers [Zr(NMe(2))(2)I(mu-NMe(2))](2) and [Zr(NEt(2))(2)I(mu-I)](2), and Zr(NEt(2))I(3) is the polymer of dimers ([Zr(NEt(2))I(2)(mu-I)](2))(n). In solution, Zr(NEt(2))(3)I is proposed to be monomeric on the basis of NMR data and a molecular weight determination. The complex Zr(NEt(2))(3)I is the most promising precursor candidate because of its physical properties.     

Synthesis and structures of bridged biscyclopentadienyl diiron complexes

Three diiron carbonyl complexes, namely [(η ⁵-C₅H₄)(η ³-C(CH₂)₂)]Fe₂(CO)₅ (1), [(C₂H₅)₂C(η ⁵-C₅H₄)₂]Fe₂(μ-CO)₂(CO)₂ (2), and [(CH₂)₄C(η ⁵-C₅H₄)(η ⁵-C₅H₃)(C₅H₉)]Fe₂(μ-CO)₂(CO)₂ (3), have been synthesized by the reactions of C₅H₄C(Me)₂, C₅H₄C(Et)₂, and C₅H₄C(CH₂)₄, respectively, with Fe(CO)₅ in refluxing xylene. The complexes have been characterized by elemental analysis, IR, and ¹H NMR spectra. The molecular structures of the complexes have been determined by single-crystal X-ray diffraction. The structures of the complexes indicate that fulvenes can be bound to transition metal centers by diverse modes.     

Synthesis and crystal structures of 1,2-diaminobenzene-Ni complexes

Treatment in different proportions of 1,2-diaminobenzene with Ni(OAc)₂ · 4H₂O in methanol results in the formation of two 1,2-diaminobenzene-Ni complexes I (C₉₂H₁₃₄N₂₄Ni₉O₂₈) and II (C₁₆H₂₂N₄NiO₄). Their structures were determined by X-ray diffraction analysis. The complexes are also characterized by elemental analysis and IR.     

Constrained-geometry aluminum complexes with eta5;eta1-coordination: syntheses, structures, and theoretical studies of dicarbollylamino aluminum(III) complexes

A series of constrained geometry complexes of formula [(eta5-RC2B9H10)CH2(eta1-NMe2)]Al(Me) (R = H, 2a; Me, 2b) was prepared in high yields from the reaction of dicarbollylamine with trimethylaluminum. These complexes showed a unique constrained geometry structure with a central aluminum atom having eta5;eta1-coordination. DFT calculations further elaborate the electronic effect of an amine sidearm on the bonding capability of dicarbollyl ligand with an aluminum atom. It has been noted that dicarbollylamines are effective ancillary ligands for the production of novel constrained geometry complexes of aluminum.     

Synthesis and crystal structures of cyclopentadienyl dimolybdenum carbonyl complexes

Reactions of the fulvenes C₅H₄C(R ₁ R ₂) [(R ₁ = CH₂CH₃, R ₂ = CH₃ (1); R ₁ = R ₂ = C₂H₅ (2); R ₁, R ₂ = (CH₂)₄ (3), R ₁,R ₂ = (CH₂)₅ (4)] with Mo(CO)₆ in refluxing xylene gave the corresponding cyclopentadienyl dimolybdenum carbonyl complexes [(η⁵-C₅H₄CR₁′R₂′Mo(CO)₃]₂ [(R ₁′ = CH₂CH₃, R ₂′ = CH₃ (5); R ₁′ = R ₂′ = C₂H₅ (6); R ₁′, R ₂′ = CH(CH₂)₃ (7); R ₁′, R ₂′ = CH(CH₂)₄ (8)], which were characterized by elemental analysis, IR and ¹H NMR spectra. The molecular structures were determined by single-crystal X-ray diffraction. The results indicated the exocyclic double bond of the ligands 1 and 2 changed into a single bond and the exocyclic double bond of the ligands 3 and 4 underwent a double-bond isomerization process.     

Synthesis and X-ray crystal structures of some isothiosemicarbazone complexes

Transition Metal Chemistry - Four complexes of a new isothiosemicarbazone ligand have been prepared and characterized as μ2-pip-(NiL)2 (1), MnL2 (2), UO2L(BrSal)BuOH (3) and (μ2-MoO2L)2...     

Ketiminate supported aluminum(III) complexes: Synthesis, characterization and reactivity

The reaction of LLi, (L = [RNC(Me)CHC(Me) = O] (R = C₂H₄NEt₂)), with AlCl₃ at −78 °C forms the mono-ketiminate product, LAlCl₂, 1, while the same reaction at 0 °C affords the bis-ketiminate complex, [{(LH)₂AlCl}(Cl₂)], 2, Reduction of 1 with Li^o, K^o or Mg^o yielded an unusual dimeric aluminum(III) species, [L′AlCl]₂, 3, where C-C coupling of the ligand backbone is observed.     

Density functional calculations for predicting structures and vibrational frequencies of aluminum chloride-fluoride complexes

Quantum chemical calculations are used to study AlCl_y−xF_x^3−y (y = 5 or 6, x = 0,…,y) species that can occur in aluminum electrorefining melts. These theoretical studies are included in a wider research program concerning the chemical instabilities in the bulk of molten salts during the refinement process. Stabilization energies, equilibrium geometries and vibrational frequencies of the complexes are calculated using the Delley functional methodology described in Ref. [1] (B. Delley, J. Chem. Phys., 92 (1990) 508). These computational simulations, discussed and compared with the experimental results demonstrate that density functional calculations can be reliably used in the study of complexes existing in molten salts. Quantum chemical calculations are accurate tools for theoretically predicting structures, physical and chemical properties and vibrational frequencies of known entities as well as unknown compounds.     

Synthesis and structures of polyiodide acetamide complexes of transition metals

Polyiodides of acetamide complexes of transition elements have been synthesized and studied by X-ray diffraction analysis. Compounds [M(AA)₆][I₁₀] (M = Mn, Fe, Co, Ni, Zn) are isostructural with the earlier studied cadmium compound. The crystals of [Co(AA)₄(H₂O)₂][I₁₂] are monoclinic: a = 17.486(6) Å, b = 15.015(4) Å, c = 7.8309(15) Å, β = 99.87(2)°, V = 2025.6(10) ų, space group C2/m, Z = 4. The crystals of [Ni(AA)₆][I₃]₂ are monoclinic: a = 23.032(9) Å, b = 12.176(4) Å, c = 18.274(5) Å, β = 139.22(3)°, V = 3347.0(19) ų, space group Cc, Z = 4.     

Synthesis and structures of boron complexes of acyl hydroxy coumarins

New boron chelates were synthesized by the reactions of 3-acetyl-4-hydroxycoumarin and 8-acyl-7-hydroxy-4-methylcoumarins with boron trifluoride etherate and hydroxybenzodioxaborole. The structure of 3-acetyl-4-difluoroboryloxycoumarin containing an intramolecular C=O...B coordination bond was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2012–2015, November, 2006.     

Synthesis and molecular structures of nitrosoarene metalloporphyrin complexes of ruthenium

Several new ruthenium porphyrins containing nitrosoarene ligands have been synthesized and characterized by IR and (1)H NMR spectroscopy, and by single-crystal X-ray crystallography. Bis-nitrosoarene complexes of the form (por)Ru(ArNO)(2)(Ar = aryl group; por = TPP, TTP; TPP = tetraphenylporphyrinato dianion, TTP = tetratolylporphyrinato dianion) were prepared in good yields from the reaction of the nitrosoarenes with (por)Ru(CO). The IR spectra of the complexes (as KBr pellets) display new bands in the 1346-1350 cm(-1) region due to nu(NO). Reactions of the (por)Ru(ArNO)(2) complexes with excess pyridine and 1-methylimidazole produce the mono-nitrosoarene complexes (por)Ru(ArNO)(py) and (por)Ru(ArNO)(1-MeIm), respectively. The IR spectra of these mono-nitrosoarene complexes reveal a lowering of nu(NO) by 14-44 cm(-1), a feature consistent with the replacement of one of the pi-acid ArNO ligands with the more basic pyridine and 1-MeIm ligands. The solid-state molecular structures of two members of each of the three classes of compounds, namely (por)Ru(ArNO)(2), (por)Ru(ArNO)(py) and (por)Ru(ArNO)(1-MeIm) were determined by single-crystal X-ray diffraction, and reveal the N-binding mode of the ArNO ligands.     

A Diene Synthesis of Quinone Aldehydes

Cycloaddition of 2-(hydroxymethyl)-1,3-butadiene with representative quinones occurs readily in refluxing toluene. Oxidative dehydrogenation of the resulting cycloadduct with activated manganese dioxide in refluxing benzene affords quinone aldehydes in good to excellent overall yield.     

Synthesis,structures and magnetic properties of two hexanuclear complexes

The reaction of salicylaldoxime (H₂salox) with Mn(ClO₄)₂ · 6H₂O, NaN(CN)₂ and NEt₃ in MeOH affords a Mn^III₆ hexanuclear complex of [Mn₆O₂(salox)₆(MeOH)₆(NCNCONH₂)₂] (1), while reaction of H₂salox with MnCl₂ · 4H₂O and NEt₄OH in EtOH affords a Mn^III₆ hexanuclear complex of [Mn₆O₂(salox)₆(EtOH)₄(H₂O)₂Cl₂] (2). Both complexes 1 and 2 contain a [Mn^III₆(μ₃-O)₂]¹⁴⁺ core, which is a known structural type in the family of Mn₆ complexes. Variable temperature magnetic susceptibilities and magnetization measurement of complexes 1 and 2 have been carried out. Exchange interactions of metal centers for complexes 1 and 2 are fitted by a full diagonalization matrix method. The fitting results indicate that both complexes 1 and 2 have the ground-state spin value of S = 4, and the ground state of complex 1 has the much closer energy to low-lying spin states than that of complex 2. Magnetization measurements at 2.0–4.0 K and 10–70 kG confirm that the ground state is S = 4, with significant magnetoanisotropy as gauged by the D value of ?0.82 cm^?1 and ?1.18 cm^?1, for 1 and 2, respectively. The frequency dependence of the out-of-phase component in alternating current magnetic susceptibilities for both complexes 1 and 2 indicates the slow magnetic relaxation of superparamagnetic behaviour with a U_eff of 27.0(1) K and τ₀ = 3.8(2) × 10^?9 s for complex 1, and U_eff of 25.1(6) K and τ₀ = 4.6(1) × 10^?8 s for complex 2.     

Synthesis and structures of new octahedral heterometal rhenium-osmium cluster complexes

New octahedral anionic heterometal rhenium-osmium cluster complexes [Re₅OsSe₈(OH)₆]³⁻ and [Re₄Os₂Se₈(OH)₆]²⁻ were synthesized starting from [Re₅OsSe₈Cl₆]³⁻ and [Re₄Os₂Se₈Cl₆]²⁻, respectively. They were isolated as salts of the compositions Cs₃[Re₅OsSe₈(OH)₆] · 11H₂O (I), K₃[Re₅OsSe₈(OH)₆] · 7H₂O (II), and K₂[Re₄Os₂Se₈(OH)₆] · 3H₂O (III). The protonation of the terminal OH ligands of [Re₅OsSe₈(OH)₆]³⁻ in an aqueous solution resulted in crystallization of a neutral complex [Re₅OsSe₈(H₂O)₃(OH)₃] · 12H₂O (IV). The compounds have been characterized by single-crystal X-ray diffraction analysis. The luminescence properties of [Re₅OsSe₈(OH)₆]³⁻ and [Re₄Os₂Se₈(OH)₆]²⁻ were studied. In addition, the electronic structures of the complexes were elucidated by DFT calculations.