Mixed schiff base,carbonyl(phosphine)rhenium(I) complexes

Summary The Re(CO)₂(L)P₂ complexes (L=N-methylsalicylideneiminate,N-phenylsalicylideneiminate, halfN,N-ethylenebis(salicylideneiminate) or 8-hydroxyquinolinate; P=dimethyl(phenyl)phosphine or triphenylphosphine) were synthesized from the ReCl(CO)₃P₂ complexes and characterized by elemental analysis, i.r. and¹H n.m.r. spectroscopy.     

Ruthenium hydride complexes of the hindered phosphine ligand tris(3-diisopropylphosphinopropyl)phosphine

The synthesis and characterization of the novel hindered tripodal phosphine ligand P(CH(2)CH(2)CH(2)P(i)Pr(2))(3) (P(3)P(3)(iPr)) (1) are reported, along with the synthesis and characterization of ruthenium chloro and hydrido complexes of 1. Complexes [RuCl(P(3)P(3)(i)Pr)][BPh(4)] (2[BPh(4)]), RuH(2)(P(3)P(3)(i)Pr) (3), and [Ru(H(2))(H)(P(3)P(3)(iPr))][BPh(4)] (4[BPh(4)]) were characterized by crystallography. Complex 2 is fluxional in solution, and low-temperature NMR spectroscopy of the complex correlates well with two dynamic processes, an exchange between stereoisomers and a faster turnstile-type exchange within one of the stereoisomers.     

Rhodium(I) carbonyl complexes of ether‐phosphine ligands and their reactivity

The reactions of dimeric complex [Rh(CO)₂Cl]₂ with hemilabile ether‐phosphine ligands Ph₂P(CH₂) _nOR [n = 1, R = CH₃ (a); n = 2, R = C₂H₅ (b)] yield cis‐[Rh(CO)₂Cl(P ～ O)] (1) [P ～ O = η ¹‐(P) coordinated]. Halide abstraction reactions of 1 with AgClO₄ produce cis‐[Rh(CO)₂(P ∩ O)]ClO₄ (2) [P ∩ O = η ²‐(P,O)chelated]. Oxidative addition reactions of 1 with CH₃I and I₂ give rhodium(III) complexes [Rh(CO)(COCH₃)ClI(P ∩ O)] (3) and [Rh(CO)ClI₂(P ∩ O)] (4) respectively. The complexes have been characterized by elemental analyses, IR, ¹H, ¹³C and ³¹P NMR spectroscopy. The catalytic activity of 1 for carbonylation of methanol is higher than that of the well‐known [Rh(CO)₂I₂]^? species. Copyright © 2002 John Wiley & Sons, Ltd.     

Quantum-chemical study of donor-acceptor interactions in rhodium(I) carbonyl carboxylate complexes with phosphine ligands

The DFT B3LYP method was used to optimize the geometries, calculate the IR spectra, and analyze the electronic structures of carbonyl(carboxylato)(phosphine)rhodium(I) complexes, namely, trans-[Rh(Cl)(CO)(PPh₃)₂], trans-[Rh(OCOR)(CO)(PPh₃)₂] (R = H, CH₃, and CF₃), and trans-[Rh(OCOH)(CO)(PX₃)₂], and free PX₃ molecules (X = H, F, CH₃, i-Pr, Cy, and Ph). A linear correlation between v(CO) in the IR spectra of trans-[Rh(OCOH)(CO)(PX₃)₂] and the HOMO energy of the free PX₃ molecule was found for phosphines with nonaromatic substituents X. It was concluded that the electronic state of the CO group is mainly determined by the σ-donor properties of phosphines. The distinctive features of the electronic structure of triphenylphosphine are discussed.     

Preparation and characterization of mixed amido,carboxylato or thiazolato carbonyl(phosphine)technetium(I) complexes

Summary The complex [Tc(PPh₃)₂(CO)₃Cl] reacts with the lithium salt of amido-carboxylato- and thiazolato-derivatives to give the new complexes (Ar= C₆H₄Me-p or C₆H₄OMe-p), [Tc(PPh₃)₂(CO)₂(amt_1,2)] [amt₁=anion of 2-(methylamino)thiazole; amt₂=anion of 2-4-methoxyphenylamino(thiazole)] and [Tc(PPh₃)₂(CO)₂- (R = Ph₂CH, PhCH₂ or CCl₃). The compounds have been characterized by elemental analysis, and i.r. and¹H n.m.r. spectra.     

Platinum and rhenium phosphine carbonyl thiolate complexes

The heterometallic complex (CO)₃(PPh₃)Re(μ-SPr)Pt(PPh₃)(CO) (I) was formed in the reaction of Re₂(μ-SPr)₂(CO)₈ with (PPh₃)₂Pt(C₂Ph₂), together with (CO)₃(PPh₃)Re(μ-SPr)₂Re(CO)₄ (II), which was also prepared by an alternative synthesis. Compounds I and II were characterized by X-ray diffraction. In I, the Re-Pt single bond, 2.7414(5) Å, is supplemented by a thiolate bridge with shortened bonds: Pt-S (2.336(2) Å) and Re-S (2.449(2) Å). The Re-P (2.469(2) Å) and Pt-P (2.329(2) Å) bonds are also shortened. Complex II resulting from replacement of one CO group in the starting rhenium complex by triphenylphosphine has no M-M bond, and the Re-S and Re-P bond lengths (2.511(2)–2.527(2) and 2.517(3) Å) are close to the length of single bonds. It is assumed that the platinum atom in I is attached to the formally double bond Re ? SPr arising upon dissociation of Re₂(μ-SPr)₂(CO)₈.     

Synthesis,reactivity and x-ray crystal structures of mixed thiazolato- or carboxylato- carbonyl(phosphine) rhenium(I) complexes

Summary The compound [Re(CO)₃(PPh₃)₂Cl] reacts with the lithium salt of thiazole derivatives (L¹H = 2-amino-benzothiazole, L²H = 2–N-methyl-aminothiazole, L³H = 2–N-phenylaminothiazole, L⁴H = 2–N-(4-methoxyphenyl)aminothiazole, L⁵H = 2–N(4-nitrophenyl)aminothiazole) to give [Re(CO)₂-(PPh₃)₂(L)]. The compounds have been characterized by elemental analysis, i.r. and¹H n.m.r. spectra. At room temperature [Re(CO)₂(PPh₃)(L²)] reacts with L⁶H (L⁶H = diphenylacetic acid), to give the carboxylato complex [Re(CO)₂ .The crystal structures of [Re(CO)₂(PPh₃)₂(L²)] (2) and [Re(CO)₂(PPh₃)₂(L⁶)] (6) were determined by x-ray crystallography. [Re(CO)₂(PPh₃)₂(L²)] crystallizes in the monoclinic space group P2₁/m witha = 9.16(1),b= 24.82(2),c =9.12(1) Å, and = 115.81(4)°; D_c = 1.56 g cm^–3for Z = 2.The structure was refined to a final R of 6.4%. The molecules have C_s symmetry. The rhenium atom is six-coordinate with approximately octahedral geometry. The anionic ligand is chelating through the nitrogen atoms and is strictly planar allowing delocalization of the -electron density. [Re(CO)₂(PPh₃)₂(L⁶)] (6) crystallizes in the monoclinic space group P2₁/n witha = 22.203(5),b = 18.651(5),c =10.653(3) Å, = 91.08(3)°, Dc = 1.47 g cm^–3 for Z = 4. The structure was refined to a final R of 4.7%. The complex is monomeric and the rhenium atom is distorted octahedral with two mutuallytrans PPh₃ ligands, twocis CO ligands and one chelating Ph₂CHCO ₂ ^– ion.     

Interaction of Cu(I) carbonyl with Pd(II) and Cu(II) complexes in aqueous and nonaqueous media

CO hydrogenation over Ni-rutile and Ni-anatase catalysts has been studied at 470–520 K. Activity of the rutile catalyst is by an order of magnitude higher and it produces C₁–C₁₅-hydrocarbons; the anatase sample yields only C₁–C₃-paraffins. At 310–330 K the Ni-anatase catalyst loses nickel, while the nickel content in the Ni-rutile sample remains practically unchanged.

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CO - 470–520 , ; C₁–C₁₅; — C₁–C₃. 310–330 - , .

     

Thermal decomposition of Cu(I) phosphine complexes

The thermal decomposition of Cu(I) phosphine complexes of the general types (CuXPPh₃)₄, [CuX(PPh₃)₂] and [CuX(PPh₃)₃] was investigated.The thermal decomposition of (CuXPPh₃)₄, where X denotes Cl^–, Br^–, I^–, NO ₃ ^– and PPh₃=P(C₆H₅)₃, occurs with formation of a phosphine oxide intermediate. For the remaining complexes this intermediate was not proved in the thermal decomposition.

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Zusammenfassung Die thermische Zersetzung der Cu(I)-Phosphinkomplexe vom allgemeinen Typ (CuXPPh₃)₄ und [CuX(PPh₃)₂], wie auch [CuX(PPh₃)₃] wurde untersucht. Die thermische Zersetzung von (CuXPPh₃)₄, wobei X=Cl^–, Br^–, I^– und NO ₃ ^– bedeutet und PPh₃=P(C₆H₅)₃, verläuft unter Bildung eines Phosphinoxid Zwischenproduktes, bei den übrigen Komplexen konnte dieses im Laufe der thermischen Zersetzung nicht nachgewiesen werden.

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Résumé On a étudié la décomposition thermique des complexes phosphine-Cu(I) de formule générale (CuXPPh₃)₄, [CuX(PPh₃)₂], [CuX(PPh₃)₃]. La décomposition thermique de (CuXPPh₃)₄, où X désigne Cl^–, Br^–, I^– et NO ₃ ^– , et PPh₃=P(C₆H₅)₃, s'effectue avec formation d'un oxyde de phosphine intermédiaire; avec les autres complexes, cet intermédiaire n'a pas été mis en évidence au cours de la décomposition thermique.

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(CuXPPb₃)₄ [CuX(PPh₃)₂] [CuX(PPh₃)₃]. (CuXPPh₃)₄, X=Cl^–, Br^–, I^–, NO ₃ ^– , PPh₃=(₆₅)₃ . .

     

Tertiary phosphine induced migratory carbonyl insertion in cyclopentadienyl complexes of iron(II)

Cyclopentadienyldicarbonylmethyliron, [CpFe(CO)₂Me] (1), undergoes migratory carbonyl insertion under the influence of isosteric phosphine ligands P(4-FC₆H₄)₃ and P(4-MeC₆H₄)₃. The products of the reaction, [CpFe(CO)(COMe)P(4-FC₆H₄)₃] (2a) and [CpFe(CO)(COMe)P(4-MeC₆H₄)₃] (2b), were characterised by X-ray crystallography. In both structures, the iron atom adopts a pseudo octahedral coordination geometry. Fe-P bond distances are the same at 2.1932(8) Å in 2a and 2b, respectively. Thus, contrary to what was expected, X-ray data could not be used to quantitatively differentiate between the two phosphine ligands in 2a and 2b. Therefore, additional spectroscopic techniques such as IR and NMR were employed. Similarly, the Fe-C bond lengths of the carbonyl (Fe-CO) and acetyl (Fe-COMe) are 1.748(3) and 1.955(3) in 2a, and 1.744(3) and 1.951(3) Å in 2b, respectively.The migratory carbonyl insertion was studied by NMR, IR, and UV-vis spectroscopies to determine the mechanism and the rate law. Results from NMR spectroscopy show that the formation of the product is accompanied by oxidation of the corresponding phosphine ligand. An increase in the reactivity of migratory carbonyl insertion for P(4-MeC₆H₄)₃ was observed when the solvent was changed from CH₂Cl₂ to MeCN. The kinetic data showed that P(4-MeC₆H₄)₃ reacts faster than P(4-FC₆H₄)₃.     

A molecular mechanics force field for rhodium(I) carbonyl phosphine complexes and its application on the oxidative addition reactions of these complexes

The main purpose of the development of an Rh(I) Carbonyl Phosphine force field was to predict the molecular structure of Rh(I) complexes as well as to compute possible intermediates or transition states during the oxidative addition of CH₃I to these complexes. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 692–703, 2000     

Some cationic carbonyl complexes of rhodium(I)

A number of cationic rhodium(I) complexes of the type [Rh(CO)₂(NN)]ClO₄, [Rh(CO)₂L₃]ClO₄ and [Rh(CO)(NN)L₂]ClO₄, where (NN) is 2,2^′-bipyridine or 1,10-phenanthroline and L is a tertiary phosphine or arsine, have been isolated and their structures assigned. The configuration of the complexes ion [Rh(CO)₂L₃]⁺ appears to depend critically on the size of the ligand L.     

Rhodium(I) carbonyl complexes based on naphthophosphacyclophanes

Naphthphosphacyclophanes based on symmetrical dihydroxynaphthalenes linked by diethylamidophospite groups were used to synthesize rhodium(I) complexes containing carb-onyl and acetylacetonato fragments. The physicochemical and spectral characteristics of the synthesized coordination systems were studied.

     

Gold(I) complexes with tertiary phosphine sulfide ligands

Phosphine sulfides and their gold(I) complexes with general formula R₃P=S—Au—X (X = Cl^–, Br^– or CN^–) were prepared and characterized by elemental analyses, i.r. and ³¹P-n.m.r. spectroscopy. A decrease in the i.r. frequency of the P=S bond in the ligands upon complexation, is indicative of S coordination to gold (I). The ³¹P-n.m.r. spectra revealed that electronegativity of the substituents and angles between them were the two most important factors influencing the ³¹P-n.m.r. chemical shifts. The phosphorus resonance was observed to be more downfield in alkyl substituted phosphine sulfides as compared to the aryl substituted phosphine sulfides. Ligand scrambling in the Cy₃P=S—Au—CN complex in solution, to form [(Cy₃P=S)₂Au]⁺ and [Au(CN)₂]^–, was investigated by ¹³C and ¹⁵N-n.m.r. spectroscopy. Equilibrium constants (K _eq) for scrambling of the Cy₃P=S—Au—CN complex and for its analogue, Cy₃P=Se—Au—CN were measured by integrating the ¹³C-n.m.r. at 297 K and were found to be 0.147 and 1.81 respectively.     

(Fluoroalkyl)phosphine complexes of nickel(0) and cobalt(I)

The synthesis of a series of (fluoroalkyl)phosphine complexes of nickel is reported. Treatment of (cod)₂Ni with dfepe (dfepe=(C₂F₅)₂PCH₂CH₂P(C₂F₅)₂) yields (dfepe)Ni(cod) (1), which has been structurally characterized. Treatment of 1 with CO or bipy results in the formation of (dfepe)Ni(CO)₂ (2) and (dfepe)Ni(bipy) (3), respectively. Addition of excess dfepe to 1 results in incomplete cod displacement to form (dfepe)₂Ni (4). The homoleptic complex 4 may be independently prepared in high yield by reduction of (acac)₂Ni with (ⁱBu)₃Al in the presence of butadiene and excess dfepe. Solvation of (dfepe)Ni(cod) in acetonitrile gives a new complex tentatively identified as (dfepe)Ni(MeCN)₂ (6), whereas dissolution of (dfepe)₂Ni in acetonitrile leads to a mixture of 6 and the partial displacement product (dfepe)(η¹-dfepe)Ni(MeCN) (5). In contrast to (R₃P)₄Ni(0) phosphine and phosphite complexes, which undergo protonation by strong anhydrous acids such as HCl, H₂SO₄ and CF₃CO₂H to give (R₃P)₄Ni(H)⁺ products, Treatment of (dfepe)₂Ni with neat CF₃CO₂H or excess HOTf in dichloromethane gave no spectroscopic evidence for (dfepe)₂Ni(H)⁺. Exposure for extended periods leads to dfepe loss and decomposition to Ni(II) products. The synthesis of the first cobalt complex of dfepe, (dfepe)Co(CO)₂H, is also reported.     

Oxidative addition of different electrophiles with rhodium(I) carbonyl complexes of unsymmetrical phosphine–phosphine monoselenide ligands

Dimeric chlorobridge complex [Rh(CO)₂Cl]₂ reacts with two equivalents of a series of unsymmetrical phosphine–phosphine monoselenide ligands, Ph₂P(CH₂)_nP(Se)Ph₂ {n = 1( a ), 2( b ), 3( c ), 4( d )}to form chelate complex [Rh(CO)Cl(P∩Se)] ( 1a ) {P∩Se = η²‐(P,Se) coordinated} and non‐chelate complexes [Rh(CO)₂Cl(P～Se)] ( 1b–d ) {P～Se = η¹‐(P) coordinated}. The complexes 1 undergo oxidative addition reactions with different electrophiles such as CH₃I, C₂H₅I, C₆H₅CH₂Cl and I₂ to produce Rh(III) complexes of the type [Rh(COR)ClX(P∩Se)] {where R = ? C₂H₅ ( 2a ), X = I; R = ? CH₂C₆H₅ ( 3a ), X = Cl}, [Rh(CO)ClI₂(P∩Se)] ( 4a ), [Rh(CO)(COCH₃)ClI(P～Se)] ( 5b–d ), [Rh(CO)(COH₅)ClI‐(P～Se)] ( 6b–d ), [Rh(CO)(COCH₂C₆H₅)Cl₂(P～Se)] ( 7b–d ) and [Rh(CO)ClI₂(P～Se)] ( 8b–d ). The kinetic study of the oxidative addition (OA) reactions of the complexes 1 with CH₃I and C₂H₅I reveals a single stage kinetics. The rate of OA of the complexes varies with the length of the ligand backbone and follows the order 1a > 1b > 1c > 1d . The CH₃I reacts with the different complexes at a rate 10–100 times faster than the C₂H₅I. The catalytic activity of complexes 1b–d for carbonylation of methanol is evaluated and a higher turnover number (TON) is obtained compared with that of the well‐known commercial species [Rh(CO)₂I₂]^?. Copyright © 2006 John Wiley & Sons, Ltd.     

Biimidazolate- and bibenzimidazolate-bridged binuclear substituted manganese(I) carbonyl complexes

Novel binuclear substituted manganese(I) carbonyls [Mn(CO)_4?nL_n]₂(μ-N-N)₂ (n = 1, (N-N)₂ = biimidazolate, L = PBuⁿ₃; (N-N)₂ = bibenzimidazolate, L = P(OMe)₃, P(OPh)₃, PPh₃, PEt₃ or PBuⁿ₃, as well as n = 2; (N-N)₂ = biimidazolate, or bibenzimidazolate, L = PBuⁿ₃, PEt₃ or P(OMe)₃) are described, in which the anions (N-N)₂ act as tetradentate bridging-groups. They were prepared by treating [Mn(CO)₄(μ-Br)]₂ with thallium or potassium salts of 2,2′-biimidazole or 2,2′-bibenzimidazole and subsequent displacement of CO by L. The structures of the complexes are discussed.     

Reactivity of rhenium(V) oxo Schiff base complexes with phosphine ligands: rearrangement and reduction reactions

The symmetric rhenium(V) oxo Schiff base complexes trans-[ReO(OH2)(acac2en)]Cl and trans-[ReOCl(acac2pn)], where acac2en and acac2pn are the tetradentate Schiff base ligands N,N'-ethylenebis(acetylacetone) diimine and N,N'-propylenebis(acetylacetone) diimine, respectively, were reacted with monodentate phosphine ligands to yield one of two unique cationic phosphine complexes depending on the ligand backbone length (en vs pn) and the identity of the phosphine ligand. Reduction of the Re(V) oxo core to Re(III) resulted on reaction of trans-[ReO(OH2)(acac2en)]Cl with triphenylphosphine or diethylphenylphosphine to yield a single reduced, disubstituted product of the general type trans-[Re(III)(PR3)2(acac2en)]+. Rather unexpectedly, a similar reaction with the stronger reducing agent triethylphosphine yielded the intramolecularly rearranged, asymmetric cis-[Re(V)O(PEt3)(acac2en)]+ complex. Reactions of trans-[Re(V)O(acac2pn)Cl] with the same phosphine ligands yielded only the rearranged asymmetric cis-[Re(V)O(PR3)(acac2pn)]+ complexes in quantitative yield. The compounds were characterized using standard spectroscopic methods, elemental analyses, cyclic voltammetry, and single-crystal X-ray diffraction. The crystallographic data for the structures reported are as follows: trans-[Re(III)(PPh3)2(acac2en)]PF6 (H48C48N2O2P2Re.PF6), 1, triclinic (P), a = 18.8261(12) A, b = 16.2517(10) A, c = 15.4556(10) A, alpha = 95.522(1) degrees , beta = 97.130(1) degrees , gamma = 91.350(1) degrees , V = 4667.4(5) A(3), Z = 4; trans-[Re(III)(PEt2Ph)2(acac2en)]PF6 (H48C32N2O2P2Re.PF6), 2, orthorhombic (Pccn), a = 10.4753(6) A, b =18.4315(10) A, c = 18.9245(11) A, V = 3653.9(4) A3, Z = 4; cis-[Re(V)O(PEt3)(acac2en)]PF6 (H33C18N2O3PRe.1.25PF6, 3, monoclinic (C2/c), a = 39.8194(15) A, b = 13.6187(5) A, c = 20.1777(8) A, beta = 107.7730(10) degrees , V = 10419.9(7) A3, Z = 16; cis-[Re(V)O(PPh3)(acac2pn)]PF6 (H35C31N2O3PRe.PF6), 4, triclinic (P), a = 10.3094(10) A, b =12.1196(12) A, c = 14.8146(15) A, alpha = 105.939(2) degrees , beta = 105.383(2) degrees , gamma = 93.525(2) degrees , V = 1698.0(3) A3, Z = 2; cis-[Re(V)O(PEt2Ph)(acac2pn)]PF6 (H35C23N2O3PRe.PF6), 5, monoclinic (P2(1)/n), a = 18.1183(18) A, b = 11.580(1) A, c = 28.519(3) A, beta = 101.861(2) degrees , V = 5855.9(10) A(3), Z = 4.     

Decomposition of electron-excited molecules of molybdenum and tungsten phosphine hydride and phosphine nitrogen complexes

The kinetics and mechanism of photodehydrogenation of the phosphine hydride complexes MH₄L₄ (M = Mo, W; L are phosphine ligands) and the formation of coordinatively unsaturated species M_L4 were studied by the absorbance of long-wavelength bands with λ_max at 450–460 nm appeared in the absorption spectra of the photoproducts. The rate constants of the reactions of the coordinatively unsaturated M(DPPE)₂ species (M = Mo, W; DPPE = Ph₂PCH₂CH₂PPh₂) with molecular nitrogen in benzene were determined (k _W = 200 s⁻¹, k _Mo = 8700 s⁻¹). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 282–284, February, 2008.