Competitive reactions of coordinated carbon monoxide and methyl isocyanide with amines

The relative reactivities of CO and CNR ligands with CH₃NH₂ were investigated in complexes which contained both ligands. Like (C₅H₅Fe(CO)₃⁺; the (C₅H₅)Fe(CO)₂(CNCH₃)⁺ complex reacts with CH₃NH₂ to give the carbamoyl complex (C₅)Fe(CO)(CNCH₃)(CONHCH₃); this is a readily reversible reaction. In contrast, (C₅H₅)Fe(CO)(CNCH₃)₂⁺ reacts with CH₃NH₂ to give the amidinium or carbene complex, (C₅H₅)Fe(CO)(CNCH₃)[C(NHCH₃)₂]⁺]. In a slow reaction, (C₅H₅)Fe(PPh₃)(CO)(CNCH₃)⁺ forms the amidinium complex, (C₅H₅)Fe(PPh₃)(CO)[C(NHCH₃)₂]⁺. Factors that affect the site of CH₃NH₂ reaction are discussed. The complexes have been characterized by IR and NMR spectroscopy; a variable temperature NMR study of (C₅H₅)Fe(CO)(CNCH₃)[C(NHCH₃)₂]⁺ indicates restricted rotation around the CN bonds of the amidinium ligand.     

Metallkomplexe mit biologisch wichtigen Liganden. CLVII [1] Halbsandwich‐Komplexe mit Isocyanoacetylaminosäureestern und Isocyanoacetyldi‐ und tripeptidestern („Isocyano‐Peptide”︁)

Metal Complexes of Biologically Important Ligands, CLVII [1] Halfsandwich Complexes of Isocyanoacetylamino acid esters and of Isocyanoacetyldi‐ and tripeptide esters (?Isocyanopeptides”?) N‐Isocyanoacetyl‐amino acid esters CNCH₂C(O) NHCH(R)CO₂CH₃ (R = CH₃, CH(CH₃)₂, CH₂CH(CH₃)₂, CH₂C₆H₅) and N‐isocyanoacetyl‐di‐ and tripeptide esters CNCH₂C(O)NHCH(R¹)C(O)NHCH(R²)CO₂C₂H₅ and CNCH₂C(O)NHCH(R¹)C(O)NHCH (R²)C(O)NHCH(R³)CO₂CH₃ (R¹ = R² = R³ = CH₂C₆H₅, R² = H, CH₂C₆H₅) are available by condensation of potassium isocyanoacetate with amino acid esters or peptide esters. These isocyanides form with chloro‐bridged complexes [(arene)M(Cl)(μ‐Cl)]₂ (arene = Cp*, p‐cymene, M = Ir, Rh, Ru) in the presence of Ag[BF₄] or Ag[CF₃SO₃] the cationic halfsandwich complexes [(arene)M(isocyanide)₃]⁺X^? (X = BF₄, CF₃SO₃).     

Homogeneous Catalysis with Dicationic PdII Complexes: Aldol reaction of methyl isocyanoacetate with benzaldehyde

A series of dicationic Pd^II-acetonitrile complexes containing bi- and tridentate nitrogen and bidentate phosphine ligands (some of which are chiral) has been prepared as their BF₄ salts. The molecular structures for two of these, [Pd(CH₃CN)₂(bipy)] (BF₄)₂ ( 4 ) and [Pd(CH₃CN)((pybox)(i-Pr))] (BF₄)₂((S,S)-pybox(i-Pr) = 2,6-bis[(S)-4′-isopropyloxazolin-2′-yl]pyridine, 5 ) have been determined by X-ray diffraction. All of these complexes are shown to be effective homogeneous catalysts for the aldol-type condensation of the isonitrile, methyl isocyanoacetate, with benzaldehyde. Two isonitrile complexes, [Pd(2,2′-bipyridyl)(CNCH₂COOCH₃)₂] (BF₄)₂ and [Pd((S,S)-pybox(i-Pr))(CNCH₂COOCH₃)] (BF₄)₂, have also been prepared.     

Synthesis,spectral characterization,properties and structures of copper(I) complexes containing novel bidentate iminopyridine ligands

Four new ligands, (4-methyl-phenyl)-pyridin-2-ylmethylene-amine (A), (2,3-dimethyl-phenyl)-pyridin-2-ylmethylene-amine (B), (2,4-dimethyl-phenyl)-pyridin-2-ylmethylene-amine (C) and (2,5-dimethyl-phenyl)-pyridin-2-ylmethylene-amine (D), and their corresponding copper(I) complexes, [Cu(A)₂]ClO₄ (1a), [Cu(B)₂]ClO₄ (1b), [Cu(C)₂]ClO₄ (1c), [Cu(D)₂]ClO₄ (1d), [Cu(A)(PPh₃)₂]ClO₄ (2a), [Cu(B)(PPh₃)₂]ClO₄ (2b), [Cu(C)(PPh₃)₂]ClO₄ (2c) and [Cu(D)(PPh₃)₂]ClO₄ (2d), have been synthesized and characterized by CHN analyses, ¹H and ¹³C NMR, IR and UV–Vis spectroscopy. The crystal structures of [Cu(B)₂]ClO₄ (1b), [Cu(C)₂]ClO₄ (1c) and [Cu(A)(PPh₃)₂]ClO₄ · 1/2CH₃CN (2a) were determined from single crystal X-ray diffraction. The coordination polyhedron about the copper(I) center in the three complexes is best described as a distorted tetrahedron. A quasireversible redox behavior is observed for the complexes.     

Cyanomethyl cyclopentadienyl complexes of cobalt

The reactions of the complexes CpCo(CO)L (Cp = cyclopentadienyl, L = CO, PPh₃) with ClCH₂CN have been investigated. Chloroacetonitrile reacts with CpCo(CO)PPh₃ to give the cationic complex [CpCo(CH₂CN)(CNCH₂Cl)PPh₃]⁺, which has been isolated and characterized. Compounds of the type [CpCo(CH₂CN)(bipy)]⁺ BPh₄^? and CpCo(CH₂CN)PPh₃CN have been obtained by substitution reactions.     

Halbsandwichkomplex des Chroms mit dem Trifluormethylisocyanid-Liganden

Halfsandwich Complexes of Chromium with the Trifluoromethyl Isocyanide Ligand The synthesis and properties of the halfsandwich complexes [η⁶-1,3,5-C₆H₃(CH₃)₃]Cr(CO)₂(CNCF₃), [η⁶-1,3,5-C₆H₃(CH₃)₃]Cr(CO)(CNCH₃)(CNCF₃) und [η⁶-1,3,5-C₆H₃(CH₃)₃]Cr(CNCF₃)₃ is reported. The vibrational spectroscopic data proof the strong π accepting character of the trifluoromethyl isocyanide ligand.     

Komplexchemie polyfunktioneller Liganden. XXXI. Komplexe des Tetrakis(diphenylphosphorylmethyl)-methan mit FeCl3, SnCl4 und SbCl5

Complex Chemistry of Polyfunctional Ligands. XXXI. Complexes of Tetrakis(diphenylphosphorylmethyl) methane with FeCl₃, SnCl₄, and SbCl₅ C[CH₂P(O)(C₆H₅)₂]₄ forms with FeCl₃ the compounds C[CH₂P(O)(C₆H₅)₂]₄ · 2FeCl₃ and C[CH₂P(O)(C₆H₅)₂]₄ · 4 FeCl₃. From their IR spectra ionic, spirocyclic structures have been derived. C[CH₂P(O)(C₆H₅)₂]₄ yields with SnCl₄ and SbCl₅ also spirocyclic compounds of the composition C[CH₂P(O)(C₆H₅)₂]₄ · 2 SnCl₄ and C[CH₂P(O)(C₆H₅)₂]₄ · 4 SbCl₅, but the SnCl₄ derivative has a nonionic structure.     

Dicopper complexes catalyzed coupling/cyclization of 2‐bromobenzoic acids with amidines leading to quinazolinones

Dicopper(I) complexes {Cu₂(bpnp)(CH₃CN)₄}(PF₆)₂] ( 2 ), [{Cu₂(bpnp)(CH₃CN)₄}(BAr₄^F)₂] ( 3 ) and [Cu₂(bpnp)Cl₂] ( 4 ) were prepared from the complexation of [Cu(CH₃CN)₄](PF₆) with 2,7‐bis(2‐pyridyl)‐1,8‐naphthyridine (bpnp) followed by anion metathesis and treatment of chloride sequentially. The X‐ray structural analysis of 4 indicates the molecule to have a twofold axis passing through the Cu₂Cl₂ core, which has the shape of a butterfly, and that the Cu atom is tetrahedrally coordinated with in a Cl₂N₂ donor set. In preliminary experiments 2 was found to be an effective catalyst in the coupling/cyclization of 2‐bromobenzoic acids with amidines, providing the corresponding quinazolinones in good yields. Copyright © 2014 John Wiley & Sons, Ltd.     

Six-membered cyclometallated derivatives of platinum(II) derived from 2-benzylpyridines. Crystal and molecular structure of [Pt(L)(Ph3P)Cl] (HL = 2-(1-methylbenzyl)pyridine)

The reaction of K₂[PtCl₄] with 2-(1-methylbenzyl)pyridine, HL, and 2-benzylpyridine, HL', affords the cyclometallated species [{Pt(L)Cl}₂] (1) and [{Pt(L')Cl}₂] (2), respectively. The chloride bridge in complex 1 can be split by neutral or anionic species to give the monomeric, [Pt(L)(Ph₃P)Cl], as two isomers, trans-P-Pt-C (3) and trans-P-Pt-N, (4), [Pt(L)(py)Cl] (5), [Pt(L)(CO)Cl] (6), [Pt(L)(CNCH₂SO₂C₆H₄CH₃-4)Cl] (7), [Pt(L)(acac)] (Hacac = 2,4-pentanedione) (8), [Pt(L)(dppm)][BF₄] (dppm = bis(diphenyl-phosphino)methane) (9), [Pt(L)(dppe)][BF₄] (dppe = bis(diphenylphosphino)ethane) (10) and [Pt(L)(dipy)][BF₄](dipy = 2,2'-dipyridine) (11). Similarly, compound 2, by reaction with Ph₃P, affords [Pt(L')(Ph₃P)Cl], as two isomers, trans-P-Pt-C (12) and trans-P-Pt-N (13). Reaction of compounds 1 or 4 with AgBF₄ in acetonitrile affords [Pt(L)(CH₃CN)₂IBF₄] (14) or [Pt(L)(Ph₃P)-(CH₃CN)][BF₄] (15). From these, [Pt(L)(Ph₃P)₂][BF₄] (16), [Pt(L)(Ph₃P)(CO)][BF₄] (17) and [Pt(L)(Ph₃P)(py)][BF₄] (18), can be obtained by displacement of the coordinated acetonitrile. The new complexes were characterized by IR, ¹H and ³¹P NMR and FAB-MS spectroscopic techniques. The NMR spectra at room temperature of most of the species derived from HL give evidence for the presence in solution of two diastereomers a and b. The structure of one diastereomer of complex 4 has been solved by single crystal X-ray diffraction, 4b. The platinum atom is in an almost square planar geometry with a P-Pt-N trans arrangement: Pt-N = 2.095(3), Pt-C = 1.998(4), Pt-P = 2.226(1) and Pt-Cl = 2.400(1) Å. The six-membered cyclometallated ring is in a boat conformation, with the CH₃ group in an equatorial position, i.e pointing away from the metal. Attempts to obtain [{Pt(L″)Cl}₂] (HL″ = 2-(dimethylbenzyl)pyridine), afforded an insoluble product heavily contaminated by platinum metal; treatment of this crude material with Ph₃P gave [Pt(L″)(Ph₃P)Cl] (19).     

Synthesis,spectroscopic investigation,structural characterization,and DFT calculations of [ReX2(N2COPh)(CH3PhCN)(PPh3)2] (X=Cl,Br)

Reactions of [ReX₂(η ²-N₂COPh-N′,O)(PPh₃)₂] with 3-methylbenzonitrile give two iso-structural complexes, [ReX₂(N₂COPh)(CH₃PhCN)(PPh₃)₂] (X?=?Cl, Br). The crystal and molecular structures of [ReCl₂(N₂COPh)(CH₃PhCN)(PPh₃)₂] (1) and [ReBr₂(N₂COPh)(CH₃PhCN)(PPh₃)₂]?·?CH₂Cl₂ (2) were determined. The electronic structures were examined with density functional theory (DFT). The spin-allowed electronic transitions were calculated with the time-dependent DFT method, and the UV-Vis spectrum has been discussed.     

Metal catalysed Brooke rearrangement of 3-Halo-1-(trimethylsilyl) propan-2-one (Halo = Cl or Br)

The complexes [IrH(CO)(PPh₃)₃], trans-[IrCI(CO)- (PPh₃)₂], [RhH(PPh₃)₄], [Pd(PPh₃)₄], [Pt(trans-stilbene)(PPh₃)₂] and [Pt(η³-CH₂-COCH₂)-(PPh₃)₂] catalyse the rearrangement of Me₃SiCH₂C(O)CH₂Cl to CH₂?C(OSiMe₃)-CH₂Cl.     

Zur solvensfreien Darstellung von Tetramethylammoniumsalzen: Synthese und Charakterisierung von [N(CH3)4]2[C2O4], [N(CH3)4][CO3(CH3)], [N(CH3)4][NO2], [N(CH3)4][CO2H] und [N(CH3)4][O2C(CH2)2CO2(CH3)]

Solvent-free Synthesis of Tetramethylammonium Salts: Synthesis and Characterization of [N(CH₃)₄]₂[C₂O₄], [N(CH₃)₄][CO₃CH₃], [N(CH₃)₄][NO₂], [N(CH₃)₄][CO₂H], and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] A general procedure to synthesize tetramethylammonium salts is presented. Several tetramethylammonium salts were prepared in a crystalline state by solvent-free reaction of trimethylamine and different methyl compounds at mild conditions: [N(CH₃)₄]₂[C₂O₄] (cubic; a = 1 114.8(3) pm), [N(CH₃)₄][CO₃CH₃] (P2₁/n; a = 813.64(3), b = 953.36(3), c = 1 131.3(4) pm, β = 90.03(1)°), [N(CH₃)₄][NO₂] (Pmmn; a = 821.2(4), b = 746.5(3), c = 551.5(2) pm), [N(CH₃)₄][CO₂H] (Pmmn; a = 792.8(7), b = 791.7(3), c = 563.3(4) pm) and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] (P2₁; a = 731.1(2), b = 826.4(3), c = 1 025.2(3) pm, β = 110.1(1)°). The tetramethylammonium salts were characterized by IR-spectroscopy and X-ray diffraction. The crystal structures of the methylcarbonate and the nitrite are described.     

Heteronuclear Alkoxide Compounds Containing Copper and Alkaline Earth Metals

The tetrameric Cu(β-diketonate) alkoxide complex [Cu(thd)(OCH₂CH₂OCH₃)]₄ (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate; 1a ) reacts with the alkaline earth metal alkoxides [M(OCH₂CH₂OCH₃)₂] (M = Ca, 2a ; M = Sr, 2b ; M = Ba, 2c ) to yield the heteronuclear compounds [Cu₂M(thd)₃(OCH₂CH₂OCH₃)₃] (M = Ca, 6a ; M = Sr, 6b ). These heterometallic complexes were also obtained in the reaction of 1a and the mixed Ca and Sr complexes of β-diketonate-alkoxide [M_x(thd)_y(OCH₂CH₂OCH₃)_2x?y] (M = Ca, x = 7, y = 6, 3 ; M = Sr, x = 5, y = 3, 4 ), respectively. In comparison, 1a reacts with the analogous [Ba(thd)(OCH₂CH₂OCH₃)] ( 5a ) to yield a[Ba₂Cu₂(thd)₄(OCH₃)₄(HOCH₂CH₂OCH₃)₂] species ( 8a .) The in situ prepared mixed-ligand Ba Compounds [Ba(thd)OR)] (R = CH₂CH₂OCH₂CH₂OCH₃, ( 5b ); R = CH₂CH₂CH₂OCH₃ ( 5c ) react with the corresponding Cu complexes [Cu(thd)(OR)]_n (R = CH₂CH₂OCH₂CH₂OCH₃), n = 4 ( 1b ); R = CH₂CH₂OCH₂CH₂OCH₃ ( 8b ); R = CH₂CH₂CH₂OCH₃ ( 8c ). However, [Cu(hfd)(OCH₂CH₂OCH₃)]₄ (hfd = 1,1,1,5,5,5,-hexafluoroacetylacetonate; 1e ) is converted in the presence of 2a–c to the simple metathesis products [M(hfd)₂] (M = Ca, Sr, Ba) and [Cu(OCH₂CH₂OCH₃)₂]. Crystalline [Ba₂Cu₂(hfd)₂(thd)₂(OCH₂CH₂CH₂OCH₃)₄(HOCH₂CH₂CH₂OCH₃)₂] ( 9 ) was isolated from the reaction of 1a with in situ prepared [Ba((hfd)OCH₂CH₂CH₂OCH₃)] ( 5d ) in 2-, methoxyethanol. X-Ray crystallographic structure determinations are reported for 6a , 6b , 8b , and 8c .     

Synthesis,Characterization and X‐ray Crystal Structures of [Cu(ncaen)2]ClO4 and [Cu(nca2en)(PPh3)2]BPh4 Complexes

A novel ligand, N,N′‐Bis‐[3‐(2‐nitrophenyl)‐allylidene]‐ethane‐1,2‐diamine (nca₂en), and their corresponding copper(I) complexes, [Cu(ncaen)₂]ClO₄ ( 1 ), and [Cu(nca₂en)(PPh₃)₂]BPh₄ ( 2 ), have been synthesized and characterized by CHN analyses, ¹H and ¹³C‐NMR, IR, and UV‐Vis spectroscopy. The crystal and molecular structures of [Cu(ncaen)₂]ClO₄ ( 1 ), and [Cu(nca₂en)(PPh₃)₂]BPh₄ ( 2 ), were determined by X‐ray crystallography from single‐crystal data. The coordination polyhedron about the copper(I) atom in the two complexes is best described as a distorted tetrahedron. A quasireversible redox behavior is observed for complex 1 and 2 (E_1/2 = 0.55 and 0.95 V, respectively).     

Synthesis, structure, spectroscopic properties, electrochemistry, and DFT correlative studies of N-[(2-pyridyl)methyliden]-6-coumarin complexes of Cu(I) and Ag(I)

6-Aminocoumarin reacts with pyridine-2-carboxaldehyde and has synthesized N-[(2-pyridyl)methyliden]-6-coumarin (L). The ligand, L, reacts with [Cu(MeCN)₄]ClO₄/AgNO₃ to synthesize Cu(I) and Ag(I) complexes of formulae, [Cu(L)₂]ClO₄ and [Ag(L)₂]NO₃, respectively. While similar reaction in the presence of PPh₃ has isolated [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃. All these compounds are characterized by FTIR, UV-Vis and ¹H NMR spectroscopic data. In case of [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃, the structures have been confirmed by X-ray crystallography. The structure of the complexes are distorted tetrahedral in which L coordinates in a N,N′ bidentate fashion and other two coordination sites are occupied by PPh₃. The ligand and the complexes are fluorescent and the fluorescence quantum yields of [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃ are higher than [Cu(L)₂]ClO₄ and [Ag(L)₂]NO₃. Cu(I) complexes show Cu(II)/Cu(I) quasireversible redox couple while Ag(I) complexes exhibit deposition of Ag(0) on the electrode surface during cyclic voltammetric experiments. gaussian 03 computations of representative complexes have been used to determine the composition and energy of molecular levels. An attempt has been made to explain solution spectra and redox properties of the complexes.     

Binuclear ruthenium complexes of fluorous phosphine ligands: Synthesis, properties, and biphasic catalytic activity. Crystal structure of [Ru(μ-O2CMe)(CO)2P(CH2CH2(CF2)5CF3)3]2

The fluorocarbon soluble, binuclear ruthenium(I) complexes [Ru(μ-O₂CMe)(CO)₂L^F]₂, where L^F is the perfluoroalkyl substituted tertiary phosphine, P(C₆H₄-4-CH₂CH₂(CF₂)₇CF₃)₃, or P(CH₂CH₂(CF₂)₅CF₃)₃, were synthesized and partition coefficients for the complexes in fluorocarbon/hydrocarbon biphases were determined. Catalytic hydrogenation of acetophenone to 1-phenylethanol in benzotrifluoride at 105 °C occured in the presence of either [Ru(μ-O₂CMe)(CO)₂P(C₆H₄-4-CH₂CH₂(CF₂)₇CF₃)₃]₂ (1) or [Ru(μ-O₂CMe)(CO)₂P(CH₂CH₂(CF₂)₅CF₃)₃]₂ (2). The X-ray crystal structure of [Ru(μ-O₂CMe)(CO)₂P(CH₂CH₂(CF₂)₅CF₃)₃]₂ was determined. The compound exhibited discrete regions of fluorous and non-fluorous packing.     

Linking of CuI Units by Tetrahedral Mo2E2 Complexes (E=P,As)

The reaction of [Cp₂Mo₂(CO)₄(μ,η^2:2-E₂)] ( A : E=P, B : E=As, Cp=C₅H₅) with the WCA-containing Cu^I salts ([Cu(CH₃CN)₄][Al{OC(CF₃)₃}₄] (CuTEF, C ), [Cu(CH₃CN)₄][BF₄] ( D ) and [Cu(CH₃CN)_3.5][FAl{OC₆F₁₀(C₆F₅)}₃] (CuFAl, E )) affords seven unprecedented coordination compounds. Depending on the E₂ ligand complex, the counter anion of the copper salt and the stoichiometry, four dinuclear copper dimers and three trinuclear copper compounds are accessible. The latter complexes reveal first linear Cu₃ arrays linked by E₂ units (E=P, As) coordinated in an η^2:1:1 coordination mode. All compounds were characterized by X-ray crystallography, NMR and IR spectroscopy, mass spectrometry and elemental analysis. To define the nature of the Cu⋅⋅⋅Cu⋅⋅⋅Cu interactions, DFT calculations were performed.     

Triethylphosphanimin-Komplexe der Acetate von Kupfer(II) und Zink. Kristallstrukturen von [Zn(O2C–CH3)2(HNPEt3)], [Cu5(O2C–CH3)10(HNPEt3)2] und [Cu(O2C–CH3)2(HNPEt3)2]

Triethylphosphanimine Complexes of the Acetates of Copper(II) and Zinc. Crystal Structures of [Zn(O₂C–CH₃)₂(HNPEt₃)], [Cu₅(O₂C–CH₃)₁₀(HNPEt₃)₂], and [Cu(O₂C–CH₃)₂(HNPEt₃)₂] The title compounds originate from the anhydrous acetates of zinc and copper(II) with trimethylsilyl-triethylphosphanimine, Me₃SiNPEt₃, in the presence of water in dichloromethane. They form colourless ( 1 ), bluish-green ( 2 ), and blue ( 3 ), respectively, single crystals, which were characterized by IR spectroscopy and by crystal structure analyses. [Zn(O₂C–CH₃)₂(HNPEt₃)] ( 1 ): Space group P 4 2₁c, Z = 8, lattice dimensions at –83 °C: a = b = 1709.6(2), c = 982.4(1) pm, R = 0.0551. 1 has a polymeric chain structure in which the zinc atoms are μ₂-bridged via the oxygen atoms of one of the two acetato groups, while the second acetato group and the phosphanimine are bonded terminally. [Cu₅(O₂C–CH₃)₁₀(HNPEt₃)₂]( 2 · 4 CH₂Cl₂): Space group P2₁/c, Z = 8, lattice dimensions at –80 °C: a = 1761.18(13), b = 4074.5(2), c = 1733.34(15) pm, β = 91.383(10)°, R = 0.0413. 2 consists of the two structural units [Cu₂(O₂C–CH₃)₄] and [Cu₃(O₂C–CH₃)₆(HNPEt₃)₂], which are connected via two of the acetato groups of the Cu₃-unit along the crystallographic a-axis to form three crystallographically independent polymeric strands. [Cu(O₂C–CH₃)₂(HNPEt₃)₂] ( 3 ): Space group P2₁/n, Z = 2, lattice dimensions at 20 °C: a = 695.49(8), b = 1217.85(10), c = 1380.05(7) pm, β = 96.451(7)°, R = 0.0291. 3 forms monomeric, centrosymmetric molecules with a square planar environment at the Cu atoms.     

Syntheses,characterizations and crystal structures of two new complexes, [Co2(CH2 =C(CH3)CO2)4(phen)2(H2O)2] and [Pb2(CH2 =C(CH3)CO2)4(phen)2]

Two new complexes, [Co₂(CH₂=C(CH₃)CO₂)₄(phen)₂(H₂O)₂] (1) and [Pb₂(CH₂=C(CH₃)CO₂)₄(phen)₂] (phen = 1,10-phenanthroline) (2), have been synthesized and structurally characterized by single crystal X-ray diffraction methods. There are two cocrystallized conformers of [Co(CH₂=C(CH₃)CO₂)₂(phen)(H₂O)] in the asymmetric unit of 1 with the Co atoms displaying similar coordination modes. In the asymmetric unit of 2, there exist two crystallographically independent [Pb(CH₂=C(CH₃)CO₂)₂(phen)] molecules with the Pb atoms showing completely different coordination geometries. Weak intermolecular interactions such as hydrogen bonding and π–π stacking are responsible for the supramolecular assembly and stabilization of the crystal structures of 1 and 2. The complexes are characterized by elemental analysis, IR spectra, and UV–Vis spectra. The fluorescent properties of 2 are also discussed.     

Some transesterification reactions of [Ir(CO2Me)(CO)2(PPh3)2]

The iridium(I) complex [Ir(CO₂Me)(CO)₂(PPh₃)₂] undergoes a transesterification reaction with the alcohols CH₂C(R)CH₂OH (R = H, Me), MeCCCH₂CH₂OH, and HOCH₂CH₂OH to afford the complexes

[Ir(CO₂CH₂CH₂CMe)(CO)₂(PPh₃)₂] and [Ir(CO₂CH₂CH₂OH)(CO)₂(PPh₃)₂], respectively. In contrast the acetylenic alcohol HCCCH₂CH₂OH gives [Ir(CCCH₂CH₂OH)(CO)PPh₃)₂]. Some reactions of the new complexes are described.