Synthesis, Characterization, and Crystal Structure of the Water Soluble Copper(I) Complex with Trisulfonated Triphenylphosphine

Synthesis, Characterization, and Crystal Structure of the Water Soluble Copper(I) Complex with Trisulfonated Triphenylphosphin

Uncommon Anionic Dioxorhenium(V) and Neutral Monooxorhenium(V) Mixed-Ligand Complexes Containing Heterofunctionalized Phosphine Ligands: Syntheses and Structural Characterization

The potentially bidentate hybrid ligand (o-hydroxyphenyl)diphenylphosphine, abbreviated POH, reacted via ligand-exchange with pentavalent rhenium precursors to give a series of six-coordinate mono- and dioxo complexes. Accurate control of the metal:ligand stoichiometric ratio allowed for the isolation of the mono-substituted [ReOCl3(PO)]- (1) and [ReOCl2(PO)(PPh3)] (2) derivatives. 1 was found to be the key intermediate for the syntheses of three more types of bis-substituted compounds:  anionic dioxo [ReO2(PO)2][A] (A = NBu4 (3), AsPh4 (4)), neutral monooxo [ReOX(PO)2] (X = Cl (5), Br (6), I (7)), and neutral monooxo mixed-ligand [ReOX(PO)(PNH)] [PNH = (o-amidophenyl)diphenylphosphine; X = Cl (8), Br (9), I (10)] complexes. In the mono-substituted complexes, the P,O-donors of the bidentate ligand spanned an equatorial (P) and the apical position (O) trans to the ReO linkage in a distorted octahedral arrangement. In all of the bis-substituted monooxo compounds, the second chelate ligated on the equatorial plane almost orthogonally positioned with respect to the first one, the two phosphorus donors showing a mutual cis-(P,P) orientation. Dioxo complexes retained the cis-(P,P) configuration with the bidentate ligands symmetrically coordinated on the equatorial plane normal to the trans-ReO2 core. All the complexes were characterized by various physical techniques, including IR, MS, and 1H/31P{1H} NMR. The X-ray structure of a representative compound for each category, namely [ReOCl3(PO)][NBu4] (1), [ReO2(PO)2][AsPh4] (4), [ReOCl(PO)2] (5), and [ReOCl(PO)(PNH)] (8), were determined. Crystals of 1 were monoclinic, P21/n, a = 10.840(3) Å, b = 22.167(6) Å, c = 15.210(4) Å, β = 95.91(2)°, and Z = 4; those of 4 were triclinic, P1̄, a = 12.679(7) Å, b = 13.082(7) Å, c = 19.649(8) Å, α = 82.64(4)°, β = 81.16(4)°, γ = 62.27(3)°, and Z = 2; those of 5 were orthorhombic, a = 10.225(4) Å, b = 14.208(6) Å, c = 21.771(9) Å, P212121, and Z = 4; and those of 8 were orthorhombic, a = 10.199(2) Å, b = 14.147(4) Å, c = 21.772(6) Å, P212121, and Z = 4. The four structures were solved by the Patterson method and refined by full-matrix least-squares procedures to R = 0.050, 0.063, 0.043, and 0.039 for 1, 4, 5 and 8, respectively. Both solution state (31P{1H} NMR) and solid state (X-ray) demonstrated a cis-(P,P) arrangement for each bis-substituted complex, with the Re atom at the center of a highly distorted octahedron. Detailed analyses of the IR spectra of this series of Re(V) compounds in the region 900−580 cm-1 allowed us the possibility to distinguish between symmetrical and asymmetrical bis-substituted complexes

Technetium and Rhenium in Five-Coordinate Symmetrical and Dissymmetrical Nitrido Complexes with Alkyl Phosphino-thiol Ligands. Synthesis and Structural Characterization

The reactivity of bulky alkylphosphino-thiol ligands (PSH) toward nitride-M(V, VI) (M = Tc/Re) precursors was investigated. Neutral five-coordinate monosubstituted complexes of the type [M(N)(PS)Cl(PPh3)] (Tc1−4, Re1−2) were prepared in moderate to high yields. It was found that these [M(N)(PS)Cl(PPh3)] species underwent ligand-exchange reactions under mild conditions when reacted with bidentate mononegative ligands having soft donor atoms such as dithiocarbamates (NaLn) to afford stable dissymmetrical mixed-substituted complexes of the type [M(N)(PS)(Ln)] (Tc5,8−10, Re5−9) containing two different bidentate chelating ligands bound to the [MN]2+ moiety. In these reactions, the dithiocarbamate replaced the two labile monodentate ligands (Cl and PPh3) leaving the [M(N)(PS)]+ building block intact. In the above reactions, technetium and rhenium were found to behave in a similar way. Instead, under more drastic conditions, reactions of PSH with [M(N)Cl2(PPh3)2] gave a mixture of monosubstituted [M(N)(PS)Cl(PPh3)] and bis-substituted species [M(N)(PS)2] (Tc11−14) in the case of technetium, whereas only monosubstituted [M(N)(PS)Cl(PPh3)] complexes were recovered for rhenium. All isolated products were characterized by elemental analysis, IR and multinuclear (1H, 13C, and 31P) NMR spectroscopies, ESI MS spectrometry, and X-ray crystal structure determination of the representative monosubstituted [Tc(N)(PStbu)Cl(PPh3)] (Tc4) and mixed-substituted [Re(N)(PScy)(L3)] (Re7) and [Re(N)(PSiso)(L4)] (Re9) complexes. The latter rhenium complexes represent the first example of a square-pyramidal nitrido Re species with the basal plane defined by a PS3 donor set. Monosubstituted [M(N)(PS)Cl(PPh3)] species bearing the substitution-inert [M(N)(PS)]+ moieties act as suitable building blocks proposed for the construction of new classes of dissymmetrical nitrido compounds with potential application in the development of essential and target specific 99mTc and 188Re radiopharmaceuticals for imaging and therapy, respectively

Synthesis and Characterization of the First Mononuclear Ni^II Phosphorane Imino Complex

Synthesis and Characterization of the First Mononuclear NiII Phosphorane Imino Comple

Synthesis and Characterization of the First Mononuclear Ni^II Phosphorane Imino Complex

Synthesis and Characterization of the First Mononuclear NiII Phosphorane Imino Comple

Oxorhenium Phosphinophenolato Complexes with Model Peptide Fragments: Synthesis, Characterization, and Stability Considerations

The synthesis and characterization of a series of mixed-ligand oxorhenium(V) complexes containing the o-diphenylphosphinophenolato ligand (HL) and model peptide fragments acting as the tridentate coligand are reported. Thus, by reacting equimolar amounts of tiopronin, Gly-Gly, Gly-l-Phe, or glutathione (GSH) peptides on the [(n-C4H9)4N][ReOCl3(L)] precursor in refluxing MeCN/MeOH or aqueous MeCN/MeOH mixtures, the following complexes were obtained:  ReO{[SC(CH3)CONCH2COO][L]}[(n-C4H9)4N], 1, ReO{[H2NCH2CONCH2COO][L]}, 2, ReO{[H2NCH2CONCH(CH2C6H5)COO][L]}, 3, and ReO{[SCH2CH(NHCOCH2CH2CHNH2COOH)CONCH2COO][L]}Na, 4. The compounds are closed-shell 18-electron oxorhenium species adopting a distorted octahedral geometry, as demonstrated by classical spectroscopical methods including multinuclear NMR. X-ray diffraction analyses for 1 and 2 are also reported. By comparative stability studies of complexes 1−3 against excess GSH it was shown that complex 3 containing the bulky C6H5CH2 substituent adjacent to the coordinated carboxylate group of Phe is the most stable complex

Oxorhenium Phosphinophenolato Complexes with Model Peptide Fragments: Synthesis, Characterization, and Stability Considerations

The synthesis and characterization of a series of mixed-ligand oxorhenium(V) complexes containing the o-diphenylphosphinophenolato ligand (HL) and model peptide fragments acting as the tridentate coligand are reported. Thus, by reacting equimolar amounts of tiopronin, Gly-Gly, Gly-l-Phe, or glutathione (GSH) peptides on the [(n-C4H9)4N][ReOCl3(L)] precursor in refluxing MeCN/MeOH or aqueous MeCN/MeOH mixtures, the following complexes were obtained:  ReO{[SC(CH3)CONCH2COO][L]}[(n-C4H9)4N], 1, ReO{[H2NCH2CONCH2COO][L]}, 2, ReO{[H2NCH2CONCH(CH2C6H5)COO][L]}, 3, and ReO{[SCH2CH(NHCOCH2CH2CHNH2COOH)CONCH2COO][L]}Na, 4. The compounds are closed-shell 18-electron oxorhenium species adopting a distorted octahedral geometry, as demonstrated by classical spectroscopical methods including multinuclear NMR. X-ray diffraction analyses for 1 and 2 are also reported. By comparative stability studies of complexes 1−3 against excess GSH it was shown that complex 3 containing the bulky C6H5CH2 substituent adjacent to the coordinated carboxylate group of Phe is the most stable complex

Novel Six-Coordinate Oxorhenium “3 + 2” Mixed-Ligand Complexes Carrying the SNS/PO Donor Atom Set: Synthesis and Characterization

Replacing the monothiolate group of the so-called “3 + 1” mixed-ligand oxorhenium(V) complexes with the bidentate phosphinophenolate ligand produces novel “3 + 2” mixed-ligand complexes carrying the SNS/PO donor atom set. Thus, reactions of either [ReOCl3(L)]- or [ReOCl2(L)(PPh3)] (HL = o-HOC6H4P(C6H5)2) with aminedithiol (H2Ln) in dichloromethane methanol solutions lead to six-coordinate mixed-ligand oxo−Re(V) complexes of the type [ReO(Ln)(L)], where H2L1 = CH3CH2N(CH2CH2SH)2 (1), H2L2 = (CH3CH2)2NCH2CH2N(CH2CH2SH)2 (2), and H2L3 = CH3CH2SCH2CH2N(CH2CH2SH)2 (3). The coordination geometry around rhenium is distorted octahedral with the SNS donors of the aminedithiolate and the phosphorus of the phosphinophenolate ligand defining the equatorial plane, while the apical positions are occupied by the oxo group and the oxygen atom of the HL ligand, as shown by single-crystal X-ray analyses of 1 and 3. The strong metal−phosphorus bonds together with the chelating properties of both ligands contribute to the stability of 18-electron [ReO(Ln)(L)] complexes. In fact, these six-coordinate species appear to be much more substitution inert than the “3 + 1” analogous complexes vs excess thiolate, such as cysteine or glutathione, during appropriate challenge reactions

Synthesis and Characterization of Six-Coordinate “3 + 2” Mixed-Ligand Oxorhenium Complexes with the <i>o</i>-Diphenylphosphinophenolato Ligand and Tridentate Coligands of Different N and S Donor Atom Combinations

A series of octahedral six-coordinate oxorhenium(V) mixed ligand complexes containing the common [ReO(L)]2+ fragment (L = o-OC6H4P(C6H5)2] have been synthesized and characterized. Hence, it was shown that the [ReO(L)]2+ moiety can accommodate a variety of tridentate ligands containing a central amine group amenable to deprotonation and different combinations of lateral groups, such as ethylamine, substituted ethylamine, ethylthiol, and ethylthioether arms. In particular, by reaction of equimolar amounts of the pertinent HLn ligands with the [(n-C4H9)4N][ReOCl3(L)] precursor in refluxing acetonitrile/methanol or dichloromethane/methanol mixtures, the following series of [ReO(Ln)(L)]+/0 oxorhenium(V) complexes has been generated:  ReO{[N(CH2CH2NH2)2][o-OC6H4P(C6H5)2]}Cl (1); ReO{[(C2H5)2NCH2CH2NCH2CH2S][o-OC6H4P(C6H5)2]} (2); ReO{[(CH2)4NCH2CH2NCH2CH2S][o-OC6H4P(C6H5)2]} (3); and ReO{[C2H5SCH2CH2NCH2CH2S][o-OC6H4P(C6H5)2]} (4). The complexes are closed-shell 18-electron oxorhenium species, which adopt octahedral geometries both in solution and in the solid state, as established by conventional physicochemical techniques including multinuclear NMR and single-crystal X-ray diffraction analyses

Synthesis and Characterization of Six-Coordinate “3 + 2” Mixed-Ligand Oxorhenium Complexes with the <i>o</i>-Diphenylphosphinophenolato Ligand and Tridentate Coligands of Different N and S Donor Atom Combinations

A series of octahedral six-coordinate oxorhenium(V) mixed ligand complexes containing the common [ReO(L)]2+ fragment (L = o-OC6H4P(C6H5)2] have been synthesized and characterized. Hence, it was shown that the [ReO(L)]2+ moiety can accommodate a variety of tridentate ligands containing a central amine group amenable to deprotonation and different combinations of lateral groups, such as ethylamine, substituted ethylamine, ethylthiol, and ethylthioether arms. In particular, by reaction of equimolar amounts of the pertinent HLn ligands with the [(n-C4H9)4N][ReOCl3(L)] precursor in refluxing acetonitrile/methanol or dichloromethane/methanol mixtures, the following series of [ReO(Ln)(L)]+/0 oxorhenium(V) complexes has been generated:  ReO{[N(CH2CH2NH2)2][o-OC6H4P(C6H5)2]}Cl (1); ReO{[(C2H5)2NCH2CH2NCH2CH2S][o-OC6H4P(C6H5)2]} (2); ReO{[(CH2)4NCH2CH2NCH2CH2S][o-OC6H4P(C6H5)2]} (3); and ReO{[C2H5SCH2CH2NCH2CH2S][o-OC6H4P(C6H5)2]} (4). The complexes are closed-shell 18-electron oxorhenium species, which adopt octahedral geometries both in solution and in the solid state, as established by conventional physicochemical techniques including multinuclear NMR and single-crystal X-ray diffraction analyses