Mono-η complexes of chromium(II) and chromium(0). Electron demanding substituents, structural and spectroscopic data comparisons

Using thermal and photochemical methods a series of new chromium complexes has been prepared: (ν⁶-p-C₆H₄F₂)Cr(CO)₃; (ν⁶-C₆H₅CF₃)Cr(CO)₃; [m-C₆H₄(CF₃)₂]Cr(CO)₃; (ν⁶-C₆H₅F)Cr(CO)₂H(SiCl₃); (ν⁶-C₆H₅F)Cr(CO)₂(SiCl₃)₂; (p-C₆H₄F₂)Cr(CO)₂-H(SiCl₃); (C₆H₅CF₃)Cr(CO)₂H(SiCl₃(p-C₆H₄F₂)Cr(CO)₂(SiCl₃)₂; C₆H₅CF₃)Cr(CO)₂(SiCl₃)₂; [m-C₆H₄(CF₃)₂]Cr(CO)₂-H(SiCl₃); [m-C₆H₄(CF₃)₂]Cr(CO)₂(SiCl₃)₂. Two compounds were structurally characterized by X-ray diffraction. These data combined with IR and ¹H NMR have allowed assessment of some of the electronic and steric effects. The Cr-arene bond is considerably longer in the Cr(II) derivatives than in the Cr(0) species. Also the Cr center, as might be expected, is less electron rich in the Cr(II) dicarbonyl disilyl derivatives. The ν⁶-p-C₆H₄F₂ ligands are slightly folded so that the C---F carbons are moved further away from the Cr center. Comparison of structural and electronic effects is made with a series of similar chromium compounds reported in the literature. These new (arene)Cr(II) derivatives possess more labile ν⁶-arene ligands, which promise a rich chemistry at the chromium center.     

Synthesis and characterization of SrCu2(O2CR)3(bdmap)3 and Bi2(O2CCH3)4(bdmap)2(H2O) (R = CH3, CF3; bdmap = 1,3-bis(dimethylamino)-2-propanolato)

New mixed metal complexes SrCu₂(O₂CR)₃(bdmap)₃ (R = CF₃ (1a), CH₃ (1b)) and a new dinuclear bismuth complex Bi₂(O₂CCH₃)₄(bdmap)₂(H₂O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF₂ and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi₂O₃ at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2J = 34.0(8) cm⁻¹. Crystal data for 1a: C₂₇H₅₁N₆O₉F₉Cu₂Sr/THF, monoclinic space group P2₁/m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) ų, Z = 2; for 1b: C₂₇H₆₀N₆O₉Cu₂Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) ų, Z = 8; for 2: C₂₂H₄₈O₁₁N₄Bi₂, monoclinic space group P2₁/c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) ų, Z = 4.     

Chemistry of the azine phosphine ligand Z,E-PPh2CH2C(Bu)=N-N=CMe(C6H4NO2-4): crystal structure of [Mo(CO)4{PPh2CH2C(Bu)=N-N=CMe(C6H4NO2-4)}]

Condensation of Z-PPh₂CH₂C(Bu^t)=NNH₂ with 4-nitroacetophenone gave the azine phosphine Z,E-PPh₂CH₂C(Bu^t)=N-N=CMe(C₆H₄NO₂-4) (I). The corresponding phsophine oxide II was prepared by treatment of I with H₂O₂. The phosphine I with [Mo(CO)₄(nbd)] (nbd=norbornadiene) gave [Mo(CO)₄{PPh₂CH₂C(Bu^t)=N-N=CMe(C₆H₄NO₂-4)}] (1a); the corresponding tungsten 1b and chromium 1c complexes were made similarly. The crystal structure of 1a was determined by X-ray diffraction and showed the presence of a six-membered chelate ring with the bulky 4-nitrophenyl group held close to the metal. Oxidation of 1a with bromine gave the seven-coordinate molybdenum (II) complex 2. Treatment of [PtMe₂(cod)] (cod=cycloocta-1,5-diene) with I at 20°C gave the dimethyl-platinum (II) complex [PtMe₂{PPh₂CH₂C(Bu^t)=N-N=CMe(C₆H₄NO₂-4)}] (3a) which with MeI gave the iodotrimethylplatinum(IV) complex 4. Treatment of 3a with C≡O opened the chelate ring to give the dimethyl(carbonyl)platinum(II) complex 5 containing a monodentate phosphine ligand. When 3a was heated in toluene solution at 110°C it gave the cyclometallated methylplatinum(II) complex [PtMe{PPh₂CH₂C(Bu^t)=N-N=CMe(C₆H₃NO₂-4)}] (6). Treatment of 6 with MeI gave the platinum(IV) complex 7. The dichloropalladium(II) complex [PdCl₂{PPh₂CH₂C(Bu^t)=N-N=CMe(C₆H₄NO₂-4)}] (3b) was prepared by treatment of [PdCl₂(NCPh)₂] with I in CH₂Cl₂. Treatment of [PtCl₂(NCMe)₂] with 2 equiv. of I gave the trans-bis(phosphine) complex 8. When 2 equiv. of I were treated with [PtCl₂(cod)] followed by NH₄PF₆ this gave the salt 9a containing two six-membered chelate rings; the analogous palladium(II) 9b) salt was also prepared. Treatment of 2 equiv. of I with [PtCl₂(cod)] followed by NH₄PF₆ gave the PF₆ salt 10 containing a six-membered chelate ring and a monodentate ligand. When 10 was treated with AgNO₃ followed by NH₄PF₆ this gave the bis-chelate complex 11 containing five- and six-membered chelate rings. Treatment of [IrCl(CO)₂(p-toluidine)] with I gave the cyclometallated iridium(III) hydride complex [IrHClCO{PPh₂CH₂C(Bu^t)=N-N=CMe(C₆H₃NO₂-4)}] (12). [RuCl₂(PPh₃)₃] with the phosphine I resulted in the Ru(II) complex 13 in which the ortho hydrogens of the 4-nitrophenyl group are agostically interacting with ruthenium. Proton, Phosphorus-31, some carbon-13 NMR and IR data have been obtained. Crystals of 1a are orthorhombic, space group Pna2₁, with a = 1819.3(2), b = 1050.0(1), c = 1614.8(2) pm and Z = 4; final R = 0.0191 for 2616 observed reflections.     

Syntheses and structures of palladium(II) and platinum(II) complexes with tridentate (Ph2PCH2CH2CH2)2S and its arsenic analogue

A series of square-planar complexes [MLCl]ClO₄ (M = Pd(II), Pt(II); L = bis(3-(diphenylphosphino)propyl)sulfide (psp), bis(3-(diphenylarsino)propyl)sulfide (asa)) have been prepared and characterized. The X-ray crystal structures of two of them have been determined: [Pd(psp)Cl]ClO₄, P2₁/c, A = 12.519(2), B = 15.766(2), C = 16.501(2) Å, β = 105.22(1)°, Z = 4; and [Pt(asa)Cl]ClO₄, P2₁/c, a = 12.583(5), B = 16.007(6), C = 16.549(6) Å, β = 104.89(3)°, Z = 4. In both structures, there is a conformational disorder between the chair and skew-boat orientation in one of the two six-membered chelate rings. The C---H…O hydrogen bond between the hybrid ligand and the perchlorate counter ion that induces the conformational disorder is discussed.     

Chiroptical properties of heterotrimetallic ‘wing-tip’ butterflies; synthesis and crystal structure of (μ-H)Ru2Fe2PdC(CO)12 (η-ß-C10H15)

HRu₂Fe₂PdC(CO)₁₂ (η³-ß-C₁₀H₁₅) cluster was prepared in the reaction of (Et₄N) [HFe₂Ru₂C(CO)₁₂] with [Pd(η³-ß-C₁₀H₁₅)Cl]₂. X-ray structural study of HRu₂Fe₂PdC(CO)₁₂ (η³-ß-C₁₀H₁₅) (where ß-C₁₀H₁₅ is ß-pinenyl) revealed a wing-tip butterfly geometry of the metal core and (1R, 2S, 3S, 5R) absolute configuration for both crystallography independent molecules in the crystal. Chiroptical properties of this cluster are compared with other clusters containing a Pd(η³-ß-C₁₀H₁₅) fragment and discussed.     

The synthesis, fluctionality and structural characterization of ReMo3H4(CO)12

The reaction of ReH₉²⁻ with Mo(diglyme)(CO)₃ leads to the formation of the mixed metal cluster trianion, ReMo₃H₄(CO)₁₂³⁻. This species has been characterized analytically, spectroscopically and through X-ray diffraction analysis. A pseudo-tetrahedral arrangement of M(CO)₃ fragments is adopted, such that each set of three carbonyl ligands eclipses the adjacent three tetrahedral edges, an apparent result of the location of the hydride ligands on the tetrahedral faces. Variable temperature NMR studies revealed a fluctional process for some of the carbonyl ligands, but not for the hydrides. Crystal data for [Me₄N]₃[ReMo₃H₄(CO)₁₂]·THF; space group P2₁/n, a = 12.157(2), B = 21.480(4), C = 15.964(3) Å, β = 98.26(1)°, Z = 4, R = 0.067 and R_w = 0.076.     

Thermal and photochemical substitution reactions of CpRe(PPh3)2H2 and CpRe(PPh3)H4. Catalytic insertion of ethylene into the C-H bond of benzene

The thermal and photochemical reactions of CpRe(PPh₃)₂H₄ and CpRe(PPh₃)H₄ (Cp = η⁵-C₅H₅) with PMe₃, P(p-tolyl)₃, PMe₂Ph, DMPE, DPPE, DPPM, CO, 2,6-xylylisocyanide and ethylene have been examined. While CpRe(PPh₃)₂H₂ is thermally inert, it will undergo photochemical substitution of one or two PPh₃ ligands. With ethylene, substitution is followed by insertion of the olefin into the C-H bond of benzene, giving ethylbenzene. CpRe(PPh₃)H₄ undergoes thermal loss of PPh₃, which leads to substituted products of the type CpRe(L) H₄. Photochemically, reductive elimination of dihydrogen occurs preferentially. The complex trans-CpRe(DMPE)H₂ was structurally characterized, crystallizing in the monoclinic space group P2₁/n (No. 14) with a = 6.249(6), b = 16.671(8), c = 13.867(7) Å, β = 92.11(6)°, V = 1443.7(2.9) Å and Z = 4. The complex trans-CpRe(PMe₂Ph)₂H₂ was structurally characterized, crystallizing in the monoclinic space group P2₁/n (No. 14) with a = 7.467(3), b = 23.874(14), c = 11.798(6) Å, β = 100.16(4)°, V = 2070.2(3.4) ų and Z = 4.     

The coordination chemistry of cationic main group clusters: syntheses and structures of [Fe3(Se2)2(CO)10] and [Fe4(Se2)3(CO)12]

The reactions of the polysulfur and selenium cationic clusters S₈²⁺ and Se₈²⁺ with various iron carbonyls were investigated. Several new chalcogen containing iron carbonyl cluster cations were isolated, depending on the nature of the counteranion. In the presence of SbF₆⁻ as a counterion, the cluster [Fe₃(E₂)₂(CO)₁₀] [SbF₆]₂·SO₂ (E = S, Se) could be isolated from the reaction of E₈²⁺ and excess iron carbonyl. The cluster is a picnic-basket shaped molecule of two iron centers linked by two Se₂ groups, with the whole fragment capped by an Fe(CO)₄ group. Crystallographic data for C₁₀O₁₂Fe₃Se₄Sb₂F₁₂S (I): space group monoclinic P2₁/c, A = 11.810(9), b = 24.023(6), c = 10.853(7) Å, β = 107.15(5)°, V = 2942(3) ų, Z = 4, R = 0.0426, R_w = 0.0503. When Sb₂F₁₁⁻ is present as the counterion, or Se₄[Sb₂F₁₁]₂ is used as the cluster cation source, a different cluster can be isolated, which has the formula [Fe₄(Se₂)₃(CO)₁₂] [SbF₆]₂·3SO₂. The dication contains two Fe₂Se₂ fragments bridged by an Se₂ group. Crystallographic data for C₁₂O₁₈Fe₄Se₆Sb₂F₁₂S₃ (III): space group triclinic , b = 18.400(9), C = 10.253(4) Å, = 93.10(4), β = 103.74(3), γ = 93.98(3)°, V = 1995(1) ų, Z = 2, R = 0.0328, R_w = 0.0325. The CO stretches in the IR spectrum all show a large shift to higher wavenumbers, suggesting almost no τ backbonding from the metals. This also correlates with the observed bond distances. All the compounds are extremely sensitive to air and water, and readily lose SO₂ when removed from the solvent. Thus all the crystals were handled at −100°C. The clusters seem to be either insoluble or unstable in all solvents investigated.     

Palladium complexes with PCP ligands.: Preparation and structural studies of two forms of [(PCP)Pd(OH2)]BF4

Abstraction of chloride from the Pd complex {[η³-2,6-(^tBu₂PCH₂)₂C₆H₃)]PdCl with AgBF₄ in THF gives {[η³-2,6-(^tBu₂PCH₂)₂C₆H₃)]Pd(THF)}⁺BF₄ ⁻. Attemped crystallization of this THF complex produced the aqua complex {[η³-2,6-(^tBu₂PCH₂)₂C₆H₃)]Pd(OH₂)}⁺BF₄ ⁻. Crystal structures of two crystalline forms of this compound are reported. In {[η³-2,6-(^tBu₂PCH₂)₂C₆H₃)]Pd(OH₂)}⁺BF₄ ⁻·THF, one hydrogen of the water is hydrogen bonded to the oxygen of the THF, and the other hydrogen is hydrogen bonded to an F of the BF₄ ⁻ anion. Another crystalline form has no THF, but has both of the hydrogens of water hydrogen bonded to different BF₄ ⁻ anions, such that two different BF₄ ⁻ anions bridge two {[η³-2,6-(^tBu₂PCH₂)₂C₆H₃)]Pd(OH₂)}⁺ cations. A crystal structure is also reported for the palladium chloride complex [η³-2,6-(^tBu₂PCH₂)₂C₆H₃)]PdCl.     

Systematic synthesis, structural characterization, and reactivity studies of vanadium(V)–citrate anions [VO2(C6H6O7)]2, isolated from aqueous solutions in the presence of different cations

The aqueous chemistry of vanadium with physiologically relevant ligands constitutes a subject of burgeoning research, extending from bacterial metalloenzymic functions to human-health physiology. Vanadium, in the form of VCl₃ and V₂O_5, reacted expediently with citric acid, in a 1:2 molar ratio in water at pH4, and, in the presence of various cations, afforded crystalline materials bearing the general formula (Cat)₂[V₂O₄(C₆H₆O₇)₂]·nH₂O (A) (Cat⁺=Na⁺, NH₄ ⁺, n=2; Me₄N⁺, K⁺, n=4). Exploration of the reactivity of A toward H₂O₂ yielded the peroxo-containing complexes (Cat)₂[V₂O₂(O₂)₂(C₆H₆O₇)₂]·2H₂O (B) (Cat⁺=K⁺, NH₄ ⁺). Both classes of compounds were characterized analytically and spectroscopically. The X-ray structures of complexes A and B emphasize the exceptional stability of the dimeric rhombic unit V^V ₂O₂, which is retained upon H₂O₂ reaction, and the preserved mode of coordination of the citrate ligand as a doubly deprotonated moiety. In these complexes, typical six and eight coordination numbers were observed for the Na⁺ and K⁺ counter-ions, respectively. The variety of synthetic approaches leading to A, along with the stepwise and direct assembly and isolation of peroxo-compounds (B), denotes the significance of reaction pathways and intermediates in vanadium(III–V)–citrate synthetic chemistry. Hence, a systematic investigation of reactivity modes in aqueous vanadium–citrate systems emerges as a crucial tool for the establishment of chemical interconnectivity among low MW complex species, potentially participating in the intricate biodistribution of that metal ion in biological fluids.     

Reactions of the haloalcohols HO(CH2)nCl (n = 2, 3) with platinum(II) - alkynyl and -alkyne complexes. X-ray crystal structure of trans-[Pt(Me) {C(OCH2CH2Cl) (CH2Ph)} (PPh3)2] [BF4]

The chloro complexes trans-[Pt(Me)(Cl)(PPh₃)₂], after treatment with AgBF₄, react with 1-alkynes HC---C---R in the presence of NEt₃ to afford the corresponding acetylide derivatives trans-[Pt(Me) (C---C---R) (PPh₃)₂] (R = p-tolyl (1), Ph (2), C(CH₃)₃ (3)). These complexes, with the exception of the t-butylacetylide complex, react with the chloroalcohols HO(CH₂)_nCl (n = 2, 3) in the presence of 1 equiv. of HBF₄ to afford the alkyl(chloroalkoxy)carbene complexes trans-[Pt(Me) {C[O(CH₂)_nCl](CH₂R) } (PPh₃)₂][BF₄] (R = p-tolyl, N = 2 (4), N = 3 (5); R=Ph, N = 2 (6)). A similar reaction of the bis(acetylide) complex trans-[Pt(C---C---Ph)₂(PMe₂Ph)₂] with 2 equiv. HBF₄ and 3-chloro-1-propanol affords trans-[Pt(C---CPh) {C(OCH₂CH₂CH₂Cl)(CH₂Ph) } (PMe₂Ph)₂][BF₄] (7). T alkyl(chloroalkoxy)-carbene complex trans-[Pt(Me) {C(OCH₂CH₂Cl)(CH₂Ph) } (PPh₃)₂][BF₄] (8) is formed by reaction of trans-[Pt(Me)(Cl)(PPh₃)₂], after treatment with AgBF₄ in HOCH₂CH₂Cl, with phenylacetylene in the presence of 1 equiv. of n-BuLi. The reaction of the dimer [Pt(Cl)(μ-Cl)(PMe₂Ph)]₂ with p-tolylacetylene and 3-chloro-1-propanol yields cis-[PtCl₂{C(OCH₂CH₂CH₂Cl)(CH₂C₆H₄-p-Me}(PMe₂Ph)] (9). The X-ray molecular structure of (8) has been determined. It crystallizes in the orthorhombic system, space group Pna2₁, with a = 11.785(2), B = 29.418(4), C = 15.409(3) Å, V = 4889(1) ų and Z = 4. The carbene ligand is perpendicular to the Pt(II) coordination plane; the PtC(carbene) bond distance is 2.01(1) Å and the short C(carbene)-O bond distance of 1.30(1) Å suggests extensive electronic delocalization within the Pt---C(carbene)---O moietry.     

Hetero-polynuclear complexes containing bridging diphenylphosphino-alkenes and -alkynes. The crystal structure of an Rh2{μ−ν:ν−P(Ph2) (CH2)3C≡CR}Co2 complex

The phosphinoalkenes Ph₂P(CH₂)_nCH=CH₂ (n= 1, 2, 3) and phosphinoalkynes Ph₂P(CH₂)_n C≡CR (R = H, N = 2, 3; R = CH₃, N = 1) have been prepared and reacted with the dirhodium complex (η−C₅H₅)₂Rh₂(μ−CO) (μ−η²−CF₃C₂CF₃). Six new complexes of the type (ν−C₅H₅)₂(Rh₂(CO) (μ−η¹:η¹−CF₃C₂CF₃)L, where L is a P-coordinated phosphinoalkene, or phosphinoalkyne have been isolated and fully characterized; the carbonyl and phosphine ligands are predominantly trans on the Rh---Rh bond, but there is spectroscopic evidence that a small amount of the cis-isomer is formed also. Treatment of the dirhodium-phosphinoalkene complexes with (η−CH₃C₅H₄)Mn(CO)₂thf resulted in coordination of the manganese to the alkene function. The Rh₂---Mn complex [(η−C₅H₅)₂Rh₂(CO) (μ−η¹:η¹−CF₃C₂CF₃) {Ph₂P(CH₂)₃CH=CH₂} (η−CH₃C₅H₄)Mn(CO)₂] was fully characterized. Simi treatment of the dirhodium-phosphinoalkyne complexes with Co₂(CO)₈ resulted in the coordination of Co₂(CO)₆ to the alkyne function. The Rh₂---Co₂ complex [(η−C₅H₅)₂Rh₂(CO) (μ−η¹:η¹−CF₃C₂CF₃) {Ph₂PCH₂C≡CCH₃}Co₂(CO)₂], C₃₇H₂₅Co₂F₆O₇PRh₂, was fully characteriz spectroscopically, and the molecular structure of this complex was determined by a single crystal X-ray diffraction study. It is triclinic, space group (C_i¹, No. 2) with a = 18.454(6), B = 11.418(3), C = 10.124(3) Å, = 112.16(2), β = 102.34(3), γ = 91.62(3)°, Z = 2. Conventional R on |F| was 0.052 fo observed (I > 3σ(I)) reflections. The Rh₂ and Co₂ parts of the molecule are distinct, the carbonyl and phosphine are mutually trans on the Rh---Rh bond, and the orientations of the alkynes are parallel for Rh₂ and perpendicular for Co₂. Attempts to induce Rh₂Co₂ cluster formation were unsuccessful.     

Heterobimetallic chloro bridgedcomplexes of (η:η−C10H16)-ruthenium(IV) with palladium(II), platinum(II), rhodium(III), iridium(III), copper(I) and rhodium(I)

Metathesis of [(η³:η³−C₁₀H₁₆)Ru(Cl) (μ−Cl)]₂ (1) with [R₃P) (Cl)M(μ-Cl)]₂ (M = Pd, Pt), [Me₂NCH₂C₆H₄Pd(μ-Cl)]₂ and [(OC)₂Rh(μ-Cl)]₂ affords the heterobimetallic chloro bridged complexes (η³:η³-C₁₀H₁₆) (Cl)Ru(μ-Cl)₂M(PR₃)(Cl) (M = Pd, Pt), (η³:η³-C₁₀H₁₆) (Cl)Ru(μ-Cl)₂PdC₆H₄CH₂NMe₂ and (η³:η³-C₁₀H₁₆) (Cl)Ru(μ-Cl)₂Rh(CO)₂, respectively. Complex 1 reacts with [Cp^*M(Cl) (μ-Cl)]₂ (M = Rh, Ir), [p-cymene Ru(Cl) (μ-Cl]₂ and [(Cy₃P)Cu(μ-Cl)]₂ to give an equilibrium of the heterobimetallic complexes and of educts. The structures of (η³:η³-C₁₀H₁₆)Ru(μ-Cl)₂Pd(PR₃) (Cl) (R = Et, Bu) and of one diastereoisomer of (η³:η³-C₁₀H₁₆)Ru(μ-Cl)₂IrCp^*(Cl) were determined by X-ray diffraction.     

Intermolecular Re---H·H---X hydrogen bonding (X = N, C) involving ReH5(PPh3)3

Ab initio (B3LYP) calculations show that PD·H---ReH₄(PH₃)₃ (PD = Proton donor) interactions follow the order PD = pyrrole > NH₃ > HCCH > C₂H₄ > CH₃---H 0 and decrease with the pK_a of the PD. For equivalent pK_a's, NH interacts more strongly than CH. However, intermolecular hydrogen-bonding of the M---H·H---C type is too weak to be detected experimentally in FTIR or UV-vis studies between ReH₅(PPh₃)₃ and PhCCH, C₆F₅H or PhCHCl₂.     

Direct nitration of aryl groups σ-bound to ruthenium(II)

A new method has been developed for the preparation of nitroaryl transition metal complexes using copper(II) nitrate in the presence of acetic anhydride (Menke conditions) to directly nitrate an aryl group which is already σ-bound to a transition metal centre. Under these conditions ruthenium(II) aryl complexes of the type: (where R₁=R₂=H; R₁=H, R₂=CH₃; R₁=CH₃, R₂=H) react to yield three distinct types of nitroaryl-containing products (I–III).

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The preparation and characterisation of these compounds are described. X-ray crystallographic data for one example of each of the three types of compound, are also reported. The compounds that have been studied crystallographically are Ru(C₆H₄NO₂-4)(η²-O₂CCH₃)(CO)(PPh₃)₂ (1a), C₄₅H₃₇NO₅P₂Ru·(CH₂Cl₂)_0.5, a = 20.254(5), b=19.437(8), c=22.629(3) Å, β=115.390(10)°, monoclinic, space group C2/c, Z=8; Ru(C6H4N[O]O-2)- Cl(CO)(PPh₃)₂ (4a), C₄₃H₃₄ClNO₃P₂Ru, a=9.331(3), b=12.443(2), c=16.346(3) Å, =82.81(2), β=85.03(2), γ=74.76(2)°, triclinic, space group P , Z=2; Ru(C₆H₂CH₃-2,NO₂-4,N[O]O-6)Cl(CO)(PPh₃)₂ (5b), C₄₄H₃₅Cl- N₂O₅P₂Ru·(CH₂Cl₂)₂, a=19.497(3), b=14.502(3), c=19.340(5) Å, β=122.79(1)°, monoclinic, space group Cc, Z=4.     

The synthesis of the tripodal phosphine CH3C{CH2P(m-CF3C6H4)2}3 and its rhodium coordination chemistry

The new tripodal phosphine CH₃C{CH₂P(m-CF₃C₆H₄)₂}₃, CF₃PPP, was prepared by reacting CH₃C(CH₂Br)₃ with Li⁺P(m-CF₃C₆H₄)₂⁻, the latter being best obtained by adding Li⁺NⁱPr₂⁻ to PH(m-CF₃C₆H₄)₂. The rhodium complexes [RhCl(CO)(CF₃PPP)], [Rh(LL)(CF₃PPP)](CF₃SO₃) (LL = 2 CO or NBD), [RhX₃(CF₃PPP)], [RhX(MeCN)₃(CF₃PPP)](CF₃SO₃)₂ (X = H and Cl), [RhCl₂(MeCN)(CF₃PPP)](CF₃SO₃) and [Rh(MeCN)₃(CF₃PPP)](CF₃SO₃)₃ were prepared and characterized. The X-ray crystal structure of [Rh(NBD)(CF₃PPP)](CF₃SO₃) is reported. The lower oxygen sensitivity of the CF₃PPP rhodium(I) complexes, relative to the corresponding species with the parent ligand CH₃C(CH₂PPh₂)₃, is attributed to the higher effective nuclear charge on the metal centers caused by the presence of the six CF₃ substituents on the terdentate phosphine. A similar effect may be responsible for the easier hydrolysis of the CF₃PPP-containing, cationic rhodium(III) complexes relative to the corresponding compounds of the parent ligand.     

Chelated alkyl halide manganese complexes (η:η-C5H4CH2CH2X)Mn(CO)2 from photolysis of (η-C5H4CH2CH2X)Mn(CO)3

Manganese tricarbonyl complexes (η⁵-C₅H₄CH₂CH₂Br)Mn(CO)₃ (3) and (η⁵-C₅H₄CH₂CH₂I)Mn(CO)₃ (4), with an alkyl halide side chain attached to the cyclopentadienyl ligand, were synthesized as possible precursors to chelated alkyl halide manganese complexes. Photolysis of 3 or 4 in toluene, hexane or acetone-d₆ resulted in CO dissociation and intramolecular coordination of the alkyl halide to manganese to produce (η⁵:η¹-C₅H₄CH₂CH₂Br)Mn(CO)₂ (5) and (η⁵:η¹-C₅H₄CH₂CH₂I)Mn(CO)₂ (6). Low temperature NMR and IR spectroscopy established the structures of 5 and 6. Photolysis of 3 in a glass matrix at 91 K demonstrated CO release from manganese. Low temperature NMR spectroscopy established that the coordinated alkyl halide complexes are stable to approximately −20°C.     

Macrocylic thioether-esters and thioether-thioesters and their palladium, platinum and silver complexes

Preparations by the high dilution method are reported for seven macrocyclic thioether-esters and thioether-thioesters (L1–;L7). Yields in these reactions between thiodiglycolyl dichloride and appropriate ,ω-diols or dithiols range from 10 to 51%. The compounds are characterized by ¹H and ¹³C NMR, IR and high resolution mass spectroscopy. They react with salts of Pd(II), Pt(II) and Ag(I) to form complexes of which MX₂·L2, (M = Pt, X = Cl; M = Pd, X = Cl, Br, I, SCN), [Pd(L2)₂][CF₃SO₃]₂·H₂O and [Ag(L5)₂][CF₃SO₃]·C₂H₅OH have been isolated and characterized by elemental analysis, IR and NMR spectroscopy. NMR spectra indicate reversible dissociation of the ligand occurs in dimethyl sulfoxide solvent for PdCl₂·L2 but not for the Pt analogue. For PtCl₂·L2, spectra indicate that the ligand is undergoing a conformational ‘wag’ about its pair of equivalent sulfurs. These remain bound to the metal while the unique sulfur moves from the apical position of the coordination sphere to a non-coordinated situation. Simultaneously, inversions at the bound sulfurs are occurring.     

Crystal growth in aqueous hydrofluoric acid and (HF)x · pyridine solutions: syntheses and crystal structures of [Ni(H2O)6][MF6] (M = Ti, Zr, Hf) and Ni3(py)12F6 · 7H2O

The syntheses and structures of [Ni(H₂O)₆]²⁺[MF₆]²⁻ (M = Ti,Zr,Hf) and Ni₃(py)₁₂F₆·7H₂O are reported. The former three compounds are isostructural, crystallizing in the trigonal space group (No. 148) with Z = 3. The lattice parameters are a = 9.489(4), C = 9.764(7) Å, with V = 761(1) ų for Ti; a = 9.727(2), C = 10.051(3) Å, with V = 823.6(6) ų for Zr; and a = 9.724(3), C = 10.028(4)Å, with V = 821.2(8)ų for Hf. The structures consist of discrete [Ni(H₂O)₆]²⁺ and [MF₆]²⁻ octahedra joined by O---HF hydrogen bond Large single crystals were grown in an aqueous hydrofluoric acid solution. Ni₃(py)₁₂F₆·7H₂O crystallizes in the monoclinic space group I2/a (No. 15) with Z = 4. The lattice parameters are a = 16.117(4), B = 8.529(3), C = 46.220(7) Å, β = 92.46(2)°, and V = 6348(5) ų. The structure consists of discrete Ni(py)₄F₂ octahedra linked through H---O---HF and H---O---HO hydrogen bonding interactions. Single c were grown from a (HF)_x·pyridine/pyridine/water solution.     

Intramolecular and intermolecular C-H activation at a cationic Pt center

Syntheses and C-H bond activation reactions of the novel electrophilic Pt^II complexes [(tmeda)Pt(CH₃)(OEt₂)][BAr₁], [(tmeda)Pt(CH₃)(THF)][BAr_f], and [(tmeda)Pt(CH₃)(NC₅F₅)][BAr_f] are described {[BAr_f]⁻ = [(3,5-C₆H₃(CF₃)₂)₄B]⁻} (tmeda is N,N,N′,N′-tetramethylethylenediamine), [(tmeda)Pt(CH₃)(OEt₂)][BAr_f] and [(tmeda)Pt(CH₃)(THF)][BAr_f] are unstable at room temperature, yielding methane and the Fischer carbene Pt^II hydrides, [(tmeda)Pt(=C(CH₃)(OCH₂CH₃))(H)][BAr_f] and . The methane liberated from [(tmeda)Pt(CH₃)(OEt₂-d₁₀)][BAr_f] consists of an isotopomeric mixture, (CH₄, CH₃D, CH₂D₂ and CHD₃), indicating a multiple H/D exchange reaction following the C-D activation and prior to methane loss. [(tmeda)Pt(CH₃)(THF-d₈)][BAr] liberates CH₄ and CH₃D. Methane-¹³C, cyclohexane, toluene, and benzene react with [(tmeda)Pt(CH₃)(NC₅F₅)][BAr_f] to yield methane and new organoplatinum complexes. Deuterated alkanes and arenes react with [(tmeda)Pt(CH₃)(NC₅F₅] [BAr_f] to give a mixture of methane isotopomers. The relevance of these results to the oxidation of alkanes by aqueous platinum complexes is discussed.