bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Structure and Magnetic Properties of a μ‐Carboxylato‐Bridged Ferromagnetic Trinuclear Copper(II) Complex with Lariat Tetraazacrown Ether as Ligand
Authors: Ma Shu‐Lan , Zhu Wen‐Xiang , Gao Song , Guo Qian‐Ling , Xu Miao‐Qiong 
Published: March 2004

AbstractFour o‐toluic acid pendant groups have been attached to a tetraaza crown ether to prepare the novel tetraazamacrocyclic ligand H4L, 4,7,13,16‐tetrakis(2‐carboxybenzyl)‐1,10‐dioxa‐4,7,13,16‐tetraazacyclooctadecane. The trinuclear copper(II) complex of the ligand, [Cu3L·2H2O]2+·2NO3−·2H2O, has been newly synthesized, and its subsequent structural characterization has revealed that it consists of three CuII cores with a isosceles triangular array and that there is a twofold rotation axis that passes through the Cu2 center. The complex contains two symmetry‐related CuN2O3 cores in a distorted square‐pyramidal geometry and one CuO4 core in a distorted square‐plane geometry. The two μ‐bidentate syn‐anti carboxylate groups bridge Cu1 with Cu2, and Cu1A with Cu2. The trinuclear copper(II) complex units are connected in a one‐dimensional zigzag chain via μ‐H2O−NO3−‐bridged hydrogen bonds. Variable‐temperature susceptibility measurements (2−300 K) reveal a ferromagnetic coupling, Ja = 8.08 cm−1, between the μ‐carboxylato‐bridged Cu1 and Cu2, or Cu1A and Cu2, and a weak antiferromagnetic interaction, Jb = −0.40 cm−1, between Cu1 and Cu1A. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Structure and Characterizations in Solid State and Solution of Dinuclear Pentacoordinated FeII and MnII Complexes and of a Linear Tetranuclear FeIII Complex Obtained with the Ligand N,N,N′,N′‐Tetrakis[(6‐methyl‐2‐pyridyl)methyl]propane‐1,3‐diamine
Authors: Balland Véronique , Anxolabéhère‐Mallart Elodie , Banse Frédéric , Rivière Eric , Bourcier Sophie , Nierlich Martine , Girerd Jean‐Jacques 
Published: March 2004

AbstractTwo neutral complexes [(L634M)Fe2Cl4]·2H2O·2CHCl3 (1) and [(L634M)Mn2Cl4]·CH3CN (2) have been synthesized {L634M = N,N,N′,N′‐tetrakis[(6‐methyl‐2‐pyridyl)methyl]propane‐1,3‐diamine} and their molecular structures established by X‐ray crystallography. Both structures are similar, with each metal center in a trigonal‐bipyramidal environment. No magnetic coupling is observed between the metal centers. UV/Vis spectra and cyclic voltammograms were recorded in CH2Cl2 and CH3CN solutions. Both complexes are stable in CH2Cl2, whereas only 2 is stable in CH3CN. On the contrary, 1 is in equilibrium with another FeII species in CH3CN. When this last solution is aerated, monocrystals of the neutral linear tetranuclear complex [(L634M)Fe4(μ‐O)3Cl6]·2CH3CN (3) can be isolated. Its structure is unusual with two FeIII ions pentacoordinate and the two others tetracoordinate with only chloro ligands and oxo bridges. The magnetic properties reveal that two consecutive metal centers are strongly antiferromagnetically coupled. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis and Carbonylation of Platinum(II) Organometallic Complexes with Bis(phosphanyl) Monosulfides − Crystal Structures of [κ2P,S‐{Ph2CH2P(S)Ph2}Pt(CH3)(Cl)] and [κP,μ‐κS‐{Ph2CH2CH2P(S)Ph2}Pt‐(CH3)]2[BF4]2
Authors: Mastrorilli Piero , Nobile Cosimo F. , Suranna Gian P. , Fanizzi Francesco P. , Ciccarella Giuseppe , Englert Ulli , Li Qi 
Published: March 2004

AbstractThe neutral complexes of formula [κ2P,S‐(dppmS)Pt(CH3)(Cl)] (1) and [κ2P,S‐(dppeS)Pt(CH3)(Cl)] (2) [dppmS = Ph2PCH2P(S)Ph2, dppeS = Ph2P(CH2)2P(S)Ph2] have been synthesised and characterised. Reaction of 1 and 2 with AgBF4 carried out in CH3CN or CH3CN/CH2Cl2 affords the corresponding monomeric cationic complexes [κ2P,S‐(dppmS)Pt(CH3CN)(CH3)][BF4] (3) and [κ2P,S‐(dppeS)Pt(CH3CN)(CH3)][BF4] (4). Complexes 3 and 4 partially dissociate in CD2Cl2, giving, in the case of 3, the asymmetric dimer {[κ2P,S‐(dppmS)](CH3)Pt{κP,μ‐κS‐(dppmS)}Pt(CH3)(CH3CN)][BF4]2 (5), and, in the case of 4, the symmetrical sulfur‐bridged dimer [κP,μ‐κS‐(dppeS)Pt(CH3)]2[BF4]2 (6). Pure 6 can be obtained by heating 4 under vacuum. Exposing CD2Cl2 solutions of the cationic complexes 3 and 4 to CO at ambient conditions brings about the formation of the monomeric methyl carbonyl complexes [κ2P,S‐(dppmS)Pt(CO)(CH3)][BF4] (CO trans to P, 7a) and [κ2P,S‐(dppeS)Pt(CO)(CH3)][BF4] (CO trans to P, 8a), which slowly transform into their CO cis to P isomers 7b and 8b, respectively. The single‐crystal X‐ray diffraction studies of 1·CD2Cl2 and 6·2CD2Cl2 are reported. Mass spectrometric analyses with APCI and ESI interfaces were also performed for all new complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Predicted Structures of the New Pnictides HfMQ in Contrast to ZrMQ (M = Ti, V; Q = P, As)
Authors: Derakhshan Shahab , Dashjav Enkhtsetseg , Kleinke Holger 
Published: March 2004

AbstractThe new pnictides HfTiP, HfTiAs and HfVAs have been prepared through arc‐melting. These arsenides form the predicted structures with (distorted) TiAs4 and VAs4 tetrahedra, while the structures of both Zr analogs (ZrTiAs and ZrVAs) are comprised of TiAs4 and VAs4 square planes, respectively. These differences stem from significant differences in the metal atom substructures. On the other hand, HfTiP and ZrTiP are isostructural. These variations were predicted by utilizing a structure map for metal‐rich pnictides and chalcogenides M2Q (M = valence‐electron poor transition metal, Q = pnicogen or chalcogen) presented in the year 2000. The HfMQ structure is stabilized by strong Hf−Q, M−Q and M−M bonds, and to a minor extent by Hf−Hf and Hf−M bonding interactions. All three new Hf1−δM1+δQ phases exhibit significant phase ranges. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
A Series of Transition Metal Bis(dicyanobenzenedithiolate) Complexes [M(dcbdt)2] (M = Fe, Co, Ni, Pd, Pt, Cu, Au and Zn)
Authors: Alves Helena , Simão Dulce , Cordeiro Santos Isabel , Gama Vasco , Teives Henriques Rui , Novais Horácio , Almeida Manuel 
Published: March 2004

AbstractA series of new M[(dcbdt)2]−z complexes of the dicyanobenzodithiolate (dcbdt) ligand with a range of transition metals (M = Co, Pd, Pt, Cu, Au and Zn) in different oxidation states (z = 0.4, 1, 2) were prepared as their nBu4N salts and characterised by X‐ray diffraction, cyclic voltammetry, EPR and static magnetic susceptibility. Their properties are discussed in comparison with the Ni and Fe analogues described by us recently. The structures of these complexes belong to four distinct groups: i) the ZnII compound 10 is triclinic P$\bar 1$
with the metal in a tetrahedral coordination geometry; ii) other MII complexes [M = Pt (8), Pd (7), Co (3) and Cu (5)] are monoclinic C2/m, and are isostructural with the NiII analogue, presenting a perfectly planar square geometry; iii) the CoIII compound 4 is triclinic P$\bar 1$
, and isostructural with the Fe and Ni analogues, with a strong dimerisation of the M(dcbdt)2 units and the metal in a square‐pyramidal coordination geometry; iv) the MIII salts with M = Au (2), Cu (6) and Pt (9) are monoclinic P21/c and the complexes are arranged as pseudo‐dimers. The EPR and static magnetic‐susceptibility measurements show that the CoII (3), CuII (5), PtIII (9) and CoIII (4) complexes are paramagnetic corresponding to an S = 1/2 state, except for CoIII, which is in a high‐spin S = 1 configuration. The solid state EPR spectra of the CoII compound presents a hyperfine structure typical of the I = 7/2 59Co. The temperature dependence of the paramagnetic susceptibility of the PtIII compound follows a singlet‐triplet model with a dimer antiferromagnetic coupling, J, of 984 K. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
(Nitrido)ruthenium(VI) and ‐osmium(VI) Complexes with Catecholate Auxiliaries: Synthesis, Structure, and Conversion into a (Phosphoraniminato)osmium(V) Complex
Authors: Fang Guo‐Su , Huang Jie‐Sheng , Zhu Nianyong , Che Chi‐Ming 
Published: March 2004

AbstractTreatment of [NnBu4][MVINCl4] (where M = Ru, Os) with catechol (H2Cat) and 3,5‐di‐tert‐butylcatechol (H2DBCat) in the presence of 2,6‐dimethylpyridine (2,6‐Me2Py) gave [NnBu4][MVIN(Cat)2] (where M = Ru 1a, Os 1b) and [2,6Me2PyH][MVIN(DBCat)2] (where M = Ru 2a, Os 2b), respectively, in 75−90 % yields. Reaction of 2b with triphenylphosphane afforded the (phosphoraniminato)osmium(V) complex [OsV(NPPh3)(DBCat)2(PPh3)] (3) in 90 % yield. X‐ray crystal structure determinations on 1a, 1b and 3 reveal M≡N distances of 1.603(4) and 1.641(8) Å (for 1a and 1b, respectively) and an Os−N(NPPh3) distance of 2.077(3) Å (for 3). The C−O distances in the three complexes range from 1.341(4) to 1.374(7) Å, indicating that the coordinated catecholate ligands adopt the catecholate(2−) state, rather than the semiquinonate(1−) or quinone states. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis, Structural Characterisation and Reactivity of New Dinuclear Monocyclopentadienyl Imidoniobium and ‐tantalum Complexes − X‐ray Crystal Structures of [{Nb(η5‐C5H4SiMe3)Cl2}2(μ‐1,4‐NC6H4N)], [{Ta(η5‐C5Me5)Cl2}2(μ‐1,4‐NC6H4N)] and [{Ta(η5‐C5Me5)(CH2SiMe3)2}2(μ‐1,4‐NC6H4N)]
Authors: Antiñolo Antonio , Dorado Iván , Fajardo Mariano , Garcés Andrés , López‐Solera Isabel , López‐Mardomingo Carmen , Kubicki Marek M. , Otero Antonio , Prashar Sanjiv 
Published: March 2004

AbstractThe preparation of a family of dinuclear monocyclopentadienyl imidoniobium and ‐tantalum complexes was achieved by two different synthetic routes. The diimido complexes [{M(Cp′)Cl2}2(μ‐1,i‐NC6H4N)] [Cp′ = η5‐C5H4SiMe3, M = Nb, i = 4 (1); Cp′ = η5‐C5H4SiMe3, M = Nb, i = 3 (2); Cp′ = η5‐C5H4SiMe3, M = Nb, i = 2 (3); Cp′ = η5‐C5Me5, M = Nb, i = 4 (4); Cp′ = η5‐C5Me5, M = Nb, i = 3 (5); Cp′ = η5‐C5H4SiMe3, M = Ta, i = 4 (6); Cp′ = η5‐C5H4SiMe3, M = Ta, i = 3 (7)] were prepared by the reaction of one equivalent of the trichloro precursor [{MCl3}2(μ‐1,i‐NC6H4N)] (M = Nb, Ta, i = 4, 3 or 2) with two equivalents of either C5H4(SiMe3)2 or C5Me5(SiMe3). Complexes 1−7 can also be prepared by the reaction of two equivalents of [MCp′Cl4] (Cp′ = η5‐C5H4SiMe3, M = Nb, Ta; Cp′ = η5‐C5Me5, M = Nb, Ta) with one equivalent of the corresponding aniline compound, N,N,N′,N′‐tetrakis(trimethylsilyl)‐1,4‐, ‐1,3‐, or ‐1,2‐phenylenediamine, respectively. The synthesis of [{Ta(Cp′)Cl2}2(μ‐1,i‐NC6H4N)] [Cp′ = η5‐C5Me5, i = 4 (8); Cp′ = η5‐C5Me5, i = 3 (9)] was only successful with the second preparative method. The reaction of 1, 2 and 8 with alkylating reagents gave the corresponding tetraalkyl derivatives, [{M(Cp′)R2}2(μ‐1,i‐NC6H4N)] [Cp′ = η5‐C5H4SiMe3, M = Nb, R = Me, i = 4 (10); Cp′ = η5‐C5H4SiMe3, M = Nb, R = CH2SiMe3, i = 4 (11); Cp′ = η5‐C5H4SiMe3, M = Nb, R = CH2Ph, i = 4 (12); Cp′ = η5‐C5H4SiMe3, M = Nb, R = Me, i = 3 (13); Cp′ = η5‐C5H4SiMe3, M = Nb, R = CH2SiMe3, i = 3 (14); Cp′ = η5‐C5H4SiMe3, M = Nb, R = CH2Ph, i = 3 (15); Cp′ = η5‐C5Me5, M = Ta, R = Me, i = 4 (16); Cp′ = η5‐C5Me5, M = Ta, R = CH2SiMe3, i = 4 (17); Cp′ = η5‐C5Me5, M = Ta, R = CH2Ph, i = 4 (18)]. The alkylated complexes with other stoichiometries, [{M(Cp′)(Me)(X)}2(μ‐1,4‐NC6H4N)] [Cp = η5‐C5H4SiMe3, M = Nb, X = Cl (19); Cp = η5‐C5H4SiMe3, M = Nb, X = NMe2 (20); Cp = η5‐C5Me5, M = Ta, X = Cl (21)], were also prepared. The molecular structures of complexes 1, 8 and 17 were determined by single‐crystal X‐ray diffraction studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Polymetallated 4‐tert‐Butylcalix[4]arene Complexes of Sodium and Potassium Stabilized by Crown Ethers: Syntheses, Structures and Activation of Carbon Dioxide
Authors: Fischer Reinald , Görls Helmar , Walther Dirk 
Published: March 2004

Abstract4‐tert‐Butylcalix[4]arene and 18‐crown‐6 react with NaH in THF to form the complex [(18‐crown‐6)(THF)Na4(4‐tert‐butylcalix[4]arene‐4H)]2·3THF (1). Analogously, the reaction with 4‐tert‐butyltetrathiacalix[4]arene in DMF results in the formation of [(18‐crown‐6)Na(dmf)1.5]2[(4‐tert‐butyltetrathiacalix[4]arene‐4H)2Na6(dmf)2] (2) The X‐ray analysis of 1 shows an Na6O6 skeleton consisting of two fused open heterocubanes. Two Na+ ions are encapsulated in the cavities of the calix[4]arene units. Additionally, two peripheral Na+ ions, each surrounded by a crown ether and one THF ligand, are connected to the central Na6O6 skeleton by one bridging oxygen of the calix[4]arene. In contrast, 2 contains the highly symmetrical anion [(4‐tert‐butyltetrathiacalix[4]arene‐4H)2Na6(dmf)2]2− and crown‐ether‐stabilized cations. While 1 shows a dynamic process in solution above 40 °C, the structure of the highly symmetrical compound 2 remains stable at higher temperatures. The solid‐state structure of the potassium complex [(dibenzo‐18‐crown‐6)K4(4‐tert‐butylcalix[4]arene‐4H)(THF)3]2·4THF (4) is similar to 1; however, the calix[4]arene units in the open heterocubane structure of 4 are shifted less than half a diameter to one another than in the sodium complex 1. According to the 1H NMR spectra complex 3a, containing 18‐crown‐6, has a very similar structure to the related complex 4. Both 1 and 4 absorb carbon dioxide in THF and are active CO2‐transfer reagents towards 2‐fluoropropiophenone; complex 2 is much less active. This clearly demonstrates the subtle influence of the structure of the alkali metal complexes on the CO2 reactivity in these types of compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis and Magnetic Properties of Single‐Crystals of MnFe2O4 Nanorods
Authors: Wang Jun , Chen Qianwang , Hou Binyang , Peng Zhenmeng 
Published: March 2004

AbstractSingle‐crystals of MnFe2O4 nanorods with an average diameter of 20 nm and length of 250 nm were synthesized by a hydrothermal process at 180 °C after 12 h. High‐resolution transmission electron microscopy (HRTEM) and electron diffraction (ED) analysis revealed that the nanorods grow along the [110] axis, which is one of the easy magnetization axes of the material MnFe2O4. It was found that the nanorods exhibited a saturation magnetization (Ms) of 68.02 emu/g, which is much higher than that of quasi‐spherical particles of MnFe2O4, prepared by other approaches such as solid‐state reaction methods (Ms = 36.7 emu/g), and coprecipitation processes followed by annealing in vacuo at 400 °C (Ms = 24.4 emu/g). The oriented growth along the easy magnetization axis of MnFe2O4 was suggested to be responsible for the improvement of magnetic properties of MnFe2O4 nanorods. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Electronic Structure of (Diiminopyridine)cobalt(I) Complexes
Authors: Knijnenburg Quinten , Hetterscheid Dennis , Kooistra T. Martijn , Budzelaar Peter H. M. 
Published: March 2004

AbstractDFT calculations show that square‐planar LCoIR complexes of a diiminopyridine ligand are best regarded as containing low‐spin CoII antiferromagnetically coupled to a ligand radical anion. The lowest triplet state, corresponding to a 3d⇄π* excitation, is calculated to be only a few kcal/mol above the ground state, and is thermally accessible. The anomalous 1H NMR chemical shifts of the LCoR complexes are suggested to be due to thermal population of the triplet state at room temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Alkali‐Metal‐Directed Hydrolytic Condensation of Trifunctional Phenylalkoxysilanes
Authors: Pozdniakova Yulia A. , Lyssenko Konstantin A. , Korlyukov Alexandr A. , Blagodatskikh Inessa V. , Auner Norbert , Katsoulis Dimitris , Shchegolikhina Olga I. 
Published: March 2004

AbstractThe alkali‐metal‐directed hydrolysis of phenyltrialkoxysilanes, PhSi(OR)3 (R = Me, Et, nBu), was performed under various reaction conditions. The alkali metal ions were used both as templating entities and as structural elements. The crystalline sodium and potassium phenylsiloxanolates (Na‐PhS and K‐PhS) were obtained in two different molecular compositions based on a cis‐tetraphenylcyclotetrasiloxanolate, cis‐[PhSi(O)O−]4, or on a cis‐triphenylcyclotrisiloxanolate, cis‐[PhSi(O)O−]3, anions assembled into a chain or double‐layer supramolecular structure through coordination with alkali cations and hydrogen‐bonding contacts. Conditions for selective preparation of crystalline Na‐PhS or K‐PhS of both structural types were identified. The molecular and crystal structures of [(Na+)3{PhSi(O)O−}3]·8H2O (2), [(Na+)3{PhSi(O)O−}3]·4H2O·1EtOH (3) and [(K+)3{PhSi(O)O−}3]2·7H2O·3MeOH (4) were determined by single‐crystal X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
EuIII Luminescence in a Hygroscopic Ionic Liquid: Effect of Water and Evidence for a Complexation Process
Authors: Billard Isabelle , Mekki Soufiane , Gaillard Clotilde , Hesemann Peter , Moutiers Gilles , Mariet Clarisse , Labet Alexandre , Bünzli Jean‐Claude G. 
Published: March 2004

AbstractThe spectroscopic characteristics (excitation, emission and lifetime) of EuIII dissolved in 1‐methyl‐3‐butylimidazolium bis(trifluoromethanesulfon)imide (BumimTf2N) are reported. In a first series of experiments, the effect of the presence of water in BumimTf2N was examined. It appears that non‐degassed solutions are most probably inhomogeneous, displaying large water clusters leading to an intense diffusion of the red light of an He:Ne laser. In these samples, the Eu emission spectrum is close to that observed in slightly acidic aqueous solutions. In contrast, when the samples were degassed the solution appeared homogeneous and water can be considered as a competitive ligand for the first coordination sphere of Eu. In a subsequent series of experiments, tetrabutylammonium chloride (TBACl) was added to the solution and the resultant species investigated. The ensuing enhancement in the metal‐centered luminescence has been interpreted in terms of changes in the inner coordination sphere of the EuIII ion and possible structures are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Peripherally Metallated Porphyrins: the First Examples of meso‐η1‐Palladio(II) and ‐Platinio(II) Complexes with Chelating Diamine Ligands
Authors: Hartnell Regan D. , Arnold Dennis P. 
Published: March 2004

AbstractThe oxidative addition of bis(dibenzylideneacetone)platinum(0) to meso‐bromo‐5,15‐diarylporphyrins in the presence of PPh3 has been shown to be an effective way of synthesising η1‐organoplatinum porphyrins in high yields. This methodology has been extended to synthesise various palladio‐ and platinioporphyrins that utilise bidentate nitrogen donor ligands [N,N,N′,N′‐tetramethylethylenediamine (tmeda) and 2,2′‐bipyridyl (bpy)] in order to enforce a cis configuration at the metal centre. The products were characterised by multinuclear NMR and UV‐Vis spectroscopy as well as fast‐atom bombardment and high‐resolution electrospray ionisation mass spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Novel Layered Lead(II) Aminodiphosphonates with Carboxylate‐Sulfonate and 1,3,5‐Benzenetricarboxylate Ligands as Pendant Groups or Intercalated Species
Authors: Ying Shao‐Ming , Mao Jiang‐Gao 
Published: March 2004

AbstractThe hydrothermal reaction of lead(II) carbonate with 3‐sulfobenzoic acid, 3‐HO3S−C6H4−CO2H, and isopropylimino‐bis(methylenephosphonic acid), (CH3)2CHN(CH2PO3H2)2 (H4L1), gave a new layered lead(II) carboxylate‐phosphonate, Pb7(3‐O3S−C6H4−CO2)(L1)3(H2O)2·2H2O (1), whereas the hydrothermal reaction of lead(II) carbonate with 1, 3,5‐benzenetricarboxylic acid (H3BTC) and N‐cyclohexylimino‐bis(methylenephosphonic acid), C6H11N(CH2PO3H2)2 (H4L2), afforded a layered complex, Pb3(HL2)(H2L2)(H2BTC)(H2O)·H3BTC·H2O (2). The structure of complex 1 contains <010> lead(II) carboxylate‐phosphonate hybrid layers, with the sulfonate group of the carboxylate‐sulfonate ligand as the pendant group. In complex 2, the lead(II) ions are interconnected through bridging diphosphonate ligands, and results in the formation of a lead(II) diphosphonate slab, which are further interlinked via hydrogen bonds between non‐coordinated phosphonate oxygen atoms to form a <001> layer. The doubly protonated H2BTC anion is bidentately chelated to a lead(II) ion through a carboxylate group, whereas the neutral H3BTC ligand is intercalated between two layers, forming hydrogen bonds with the non‐coordinated carboxylate groups of the H2BTC anion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Aminomethyl and Aminoacetyl Complexes of Palladium(II), Platinum(II), Iron(II) and Rhenium(I) with N‐Phthaloyl as Amino Protecting Group and Mechanistic Studies on the Palladium‐Catalyzed Amidocarbonylation
Authors: Enzmann Armin , Eckert Markus , Ponikwar Walter , Polborn Kurt , Schneiderbauer Stefan , Beller Matthias , Beck Wolfgang 
Published: March 2004

AbstractNew aminomethyl and aminoacetyl complexes with N‐phthaloyl as the amino protecting group were synthesised by oxidative addition of N‐phthaloylmethyl or ‐acetyl halide to carbonylmetallates or to Pd(PPh3)4 or [Pt(C2H4)(PPh3)2] to give [Re{C(O)CH2N‐phthaloyl}(CO)5] (1), [FeCp(CH2N‐phthaloyl)(CO)2] (2), [FeCp{C(O)CH2N‐phthaloyl}(CO)2] (3), trans‐[PdBr(CH2N‐phthaloyl)(PPh3)2] (4) and trans‐[Pd{C(O)CH2N‐phthaloyl}(X)(PPh3)2] (X = Br, Cl; 5, 6). The bis(phosphane) complexes [Pd(CH2N‐phthaloyl)(X)(R2PCH2CH2PR2)] and [Pd{C(O)CH2N‐phthaloyl}(X)(R2PCH2CH2PR2)] (X = Cl, Br; R = Ph, C6H11) 8−13 were obtained by ligand exchange from 4, 5 or 6 with the corresponding bis(phosphanes). Halide abstraction from 4, 5, 6, 10, 11 or 12 gives the cationic complexes 14 and 15 with formation of a five‐membered chelate ring which includes one carbonyl atom of the phthaloyl group. The reaction of 6 with the tridentate ligand PhP(CH2CH2PPh2)2 affords the five‐coordinate complex 16 and from [Pt(C2H4)(PPh3)2] and organic halides the platinum(II) complexes trans‐[Pt(CH2N‐phthaloyl)(Cl)(PPh3)2] (17) and [PtC(O)CH(CH2Ph)N‐phthaloyl(Cl)(PPh3)2] (18) were isolated. The structures of 2, 11, 14, 15 and 16 were determined by single‐crystal X‐ray analysis. The mechanism of the palladium‐catalysed amidocarbonylation was studied using phthalimide, formaldehyde and CO as a model system which gives N‐phthaloylglycine in good yield. The proposed elementary steps in the palladium‐catalysed amidocarbonylation could be verified by use of the possible intermediates phthaloyl‐NCH2OH and phthaloyl‐NCH2Br as substrates, by oxidative addition of phthaloylmethyl bromide to Pd0, by insertion of CO into the palladium‐carbon‐bond of 4 and 8 with formation of 5 or 9, respectively, and by use of the isolated possible intermediates 4, 5 and 14 as catalysts. Thus, all crucial steps of the palladium‐catalysed amidocarbonylation with the model system phthalimide/formaldehyde/CO have been verified for the first time. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)