Heterotrimetallic Compounds Research Articles

Revealing the Role of the Cyaphide Ion as a Bridging Ligand in Heterometallic Complexes.

The synthesis of heterometallic transition metal complexes featuring bridging cyaphide ions (C≡P−) is reported. These are synthesized from reactions of Au(IDipp)(CP) (IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) with electron‐rich, nucleophilic transition metal reagents, affording Au(IDipp)(μ2−C≡P)Ni(MeI i Pr)2 (MeI i Pr=1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) and Au(IDipp)(μ2−C≡P)Rh(Cp*)(PMe3). These studies reveal that, in contrast to the cyanide ion, bimetallic cyaphido complexes strongly favor a η1 : η2 coordination mode that maximizes the interaction of the second metal (Ni, Rh) with the π‐manifold of the ion (and not the phosphorus atom lone pair). End‐on bridging can be effectively unlocked by blocking the π‐manifold, as demonstrated by reaction of Au(IDipp)(μ2−C≡P)Rh(Cp*)(PMe3) with an electrophilic transition metal reagent, W(CO)5(THF), which affords the heterotrimetallic compound Au(IDipp)(μ3−C≡P)[Rh(Cp*)(PMe3)][W(CO)5].

Revealing the Role of the Cyaphide Ion as a Bridging Ligand in Heterometallic Complexes

AbstractThe synthesis of heterometallic transition metal complexes featuring bridging cyaphide ions (C≡P−) is reported. These are synthesized from reactions of Au(IDipp)(CP) (IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) with electron‐rich, nucleophilic transition metal reagents, affording Au(IDipp)(μ2−C≡P)Ni(MeIiPr)2 (MeIiPr=1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) and Au(IDipp)(μ2−C≡P)Rh(Cp*)(PMe3). These studies reveal that, in contrast to the cyanide ion, bimetallic cyaphido complexes strongly favor a η1 : η2 coordination mode that maximizes the interaction of the second metal (Ni, Rh) with the π‐manifold of the ion (and not the phosphorus atom lone pair). End‐on bridging can be effectively unlocked by blocking the π‐manifold, as demonstrated by reaction of Au(IDipp)(μ2−C≡P)Rh(Cp*)(PMe3) with an electrophilic transition metal reagent, W(CO)5(THF), which affords the heterotrimetallic compound Au(IDipp)(μ3−C≡P)[Rh(Cp*)(PMe3)][W(CO)5].

A pair of chiral Cu(II)‐Tb(III)‐Fe(III) heterotrimetallic enantiomers: Structural, luminescent, and magnetic studies

AbstractOne chiral heterotrimetallic compound, [Cu(H2O){(R,R)‐valcy}Tb(CH3OH)2(H2O)(μ‐CN)Fe(CN)5]·[Cu(H2O){(R,R)‐valcy}Tb(CH3OH)1.5(H2O)1.5(μ‐CN)Fe(CN)5]·7.85H2O·2CH3OH (1) (H2(R,R)‐valcy = N,N′‐bis(3‐methoxysalicylidene)‐1R,2R‐1,2‐diaminocyclohexane), has been prepared and structurally characterized by X‐ray single‐crystal diffraction. In 1, the asymmetric trinuclear {CuIITbIIIFeIII} units are assembled into 1‐D supramolecular single chain by hydrogen‐bonds and the supramolecular chains are further connected into 2D sheets. Magnetic studies show overall weak ferromagnetic interaction and magnetic anisotropy. The enantiomer of 1, denoted as complex 2, derived from N,N′‐bis(3‐methoxysalicylidene)‐1S,2S‐1,2‐diaminocyclohexane was also synthesized and characterized by PXRD, Infrared spectra, CD spectra, and fluorescence spectra. The results indicated that complexes 1 and 2 are isomorphous exhibiting similar fluorescence properties.

Paramagnetic Metal-Metal Bonded Heterometallic Complexes.

Significant progress has been made in the past 10-15 years on the design, synthesis, and properties of multimetallic coordination complexes with heterometallic metal-metal bonds that are paramagnetic. Several general classes have been explored including heterobimetallic compounds, heterotrimetallic compounds of either linear or triangular geometry, discrete molecular compounds containing a linear array of more than three metal atoms, and coordination polymers with a heterometallic metal-metal bonded backbone. We focus in this Review on the synthetic methods employed to access these compounds, their structural features, magnetic properties, and electronic structure. Regarding the metal-metal bond distances, we make use of the formal shortness ratio (FSR) for comparison of bond distances between a broad range of metal atoms of different sizes. The magnetic properties of these compounds can be described using an extension of the Goodenough-Kanamori rules to cases where two magnetic ions interact via a third metal atom. In describing the electronic structure, we focus on the ability (or not) of electrons to be delocalized across heterometallic bonds, allowing for rationalizations and predictions of single-molecule conductance measurements in paramagnetic heterometallic molecular wires.

Three to tango requires a site-specific substitution: heterotrimetallic molecular precursors for high-voltage rechargeable batteries.

Design of heterotrimetallic molecules, especially those containing at least two different metals with close atomic numbers, radii, and the same coordination number/environment is a challenging task. This quest is greatly facilitated by having a heterobimetallic parent molecule that features multiple metal sites with only some of those displaying substitutional flexibility. Recently, a unique heterobimetallic complex LiMn2(thd)5 (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) has been introduced as a single-source precursor for the preparation of a popular spinel cathode material, LiMn2O4. Theoretical calculations convincingly predict that in the above trinuclear molecule only one of the Mn sites is sufficiently flexible to be substituted with another 3d transition metal. Following those predictions, two heterotrimetallic complexes, LiMn2-x Co x (thd)5 (x = 1 (1a) and 0.5 (1b)), that represent full and partial substitution, respectively, of Co for Mn in the parent molecule, have been synthesized. X-ray structural elucidation clearly showed that only one transition metal position in the trinuclear molecule contains Co, while the other site remains fully occupied by Mn. A number of techniques have been employed for deciphering the structure and composition of heterotrimetallic compounds. Synchrotron resonant diffraction experiments unambiguously assigned 3d transition metal positions as well as provided a precise "site-specific Mn/Co elemental analysis" in a single crystal, even in an extremely difficult case of severely disordered structure formed by the superposition of two enantiomers. DART mass spectrometry and magnetic measurements clearly confirmed the presence of heterotrimetallic species LiMnCo(thd)5 rather than a statistical mixture of two heterobimetallic LiMn2(thd)5 and LiCo2(thd)5 molecules. Heterometallic precursors 1a and 1b were found to exhibit a clean decomposition yielding phase-pure LiMnCoO4 and LiMn1.5Co0.5O4 spinels, respectively, at the relatively low temperature of 400 °C. The latter oxide represents an important "5V spinel" cathode material for the lithium ion batteries. Transmission electron microscopy confirmed a homogeneous distribution of transition metals in quaternary oxides obtained by pyrolysis of single-source precursors.

Facile Axial Ligand Substitution in Linear Mo≣Mo-Ni Complexes.

Clean axial ligand substitution reactions of heterometallic extended metal atom chains (HEMACs) supported by the dpa ligand (dpa = 2,2'-dipyridylamine) have been synthetically challenging due to side reactions that alter the trimetallic core. Following the hypothesis that a heterometallic core containing second-row transition metals would be more robust toward ligand substitution, we report the synthesis of three new heterotrimetallic compounds, Mo2Ni(dpa)4(OTf)2 (1), Mo2Ni(dpa)4(NCS)2 (2), and Mo2Ni(dpa)4(NCSe)2 (3) that are obtained cleanly and in good yield. Compound 1 may be synthesized either directly by reaction of Ni(OTf)2 with Mo2(dpa)4 (4) or indirectly, by reaction of Mo2Ni(dpa)4Cl2 (5) with 2 equiv of TlOTf. Axial ligand substitution on 1 via solutions containing NaNCS or KNCSe afford 2 or 3, respectively. X-ray crystal structures of 1, 2, and 3 present short Mo-Ni distances of 2.458(8)Å /2.47(1) Å, 2.548(1), and 2.546(1), respectively. Density functional theory (DFT) calculations indicate a 3-center 3-electron σ bonding interaction between the Mo2 quadruply bonded core and the Ni in both 1 and 2. These complexes were analyzed by SQUID magnetometry, supporting the presence of a high spin Ni2+ center with S = 1.

Ruthenium Carbon-Rich Group as a Redox-Switchable Metal Coupling Unit in Linear Trinuclear Complexes.

The preparation and properties of novel ruthenium carbon-rich complexes [(Ph-C≡C-)2-nRu(dppe)2(-C≡C-bipyM(hfac)2)n] (n = 1, 2; M = CuII, MnII; bipy = 2,2'-bipyridin-5-yl) characterized by single-crystal X-ray diffraction and designed for molecular magnetism are reported. With the help of EPR spectroscopy, we show that the neutral ruthenium system sets up a magnetic coupling between two remote paramagnetic CuII units. More specifically, these copper compounds are unique examples of bimetallic and linear heterotrimetallic compounds for which a complete rationalization of the magnetic interactions could be made for exceptionally long distances between the spin carriers (8.3 Å between adjacent Cu and Ru centers, 16.6 Å between external Cu centers) and compared at two different redox states. Surprisingly, oxidation of the ruthenium redox-active metal coupling unit (MCU), which introduces an additional spin unit on the carbon-rich part, leads to weaker magnetic interactions. In contrast, in the simpler parent complexes bearing only one paramagnetic metal unit [Ph-C≡C-Ru(dppe)2-C≡C-bipyCu(hfac)2], one-electron oxidation of the ruthenium bis(acetylide) unit generates an interaction between the Cu and Ru spin carriers of magnitude comparable to that observed between the two far apart Cu ions in the above corresponding neutral trimetallic system. Evaluation and rationalization of this coupling with theoretical tools are in rational agreement with experiments for such complex systems.

Synthesis, structures and magnetic properties of chiral 3d–3d′–4f heterotrimetallic complexes based on [(Tp*)Fe(CN)3]−

A series of chiral cyano- and phenolate-bridged heterotrimetallic compounds have been obtained. The Dy and Tb derivatives exhibit similar single-molecule magnetic behaviors under a 1000 Oe dc field.

Bifunctional Chalcogen Linkers for the Stepwise Generation of Multimetallic Assemblies and Functionalized Nanoparticles.

The disulfide ligand (SC6H4CO2H-4)2 acts as a simple but versatile linker for a range of group 8 transition metals through reaction of the oxygen donors. This leads to a range of homobimetallic ruthenium and osmium alkenyl compounds, [{M(CH═CHR)(CO)(PPh3)2(O2CC6H4S-4)}2] (M = Ru, Os; R = C6H4Me-4). Additional metal-based functionality can be added through the use of precursors incorporating rhenium bipyridine units (R = (bpy)ReCl(CO)3). The more robust diphosphine ligands in [{Ru(dppm)2(O2CC6H4S-4)}2]2+ (dppm = diphenylphosphinomethane) allow reduction of the disulfide bond with sodium borohydride to yield the thiol complex [Ru(O2CC6H4SH-4)(dppm)2]+. This complex reacts with [AuCl(PPh3)] to afford the bimetallic compound [Ru(dppm)2(O2CC6H4S-4)Au(PPh3)]+. However, an improved route to the same and related heterobimetallic compounds is provided by the reaction of cis-[RuCl2(dppm)2] with [Au(SC6H4CO2H-4)(L)] (L = PPh3, PCy3, PMe3, IDip) in the presence of base and NH4PF6 (IDip = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). The heterotrimetallic compound [Au(SC6H4CO2Ru(dppm)2)2]+ is accessible through the reaction of the homoleptic gold(I) dithiolate [Au(SC6H4CO2H-4)2]PPN (PPN = bis(triphenylphosphine)iminium) with cis-[RuCl2(dppm)2]. Without departure from the same methodology, greater complexity can be incorporated into the system to provide the penta- and heptametallic assemblies [(dppf){AuSC6H4CO2Ru(dppm)2}2]2+ and [(dppf){AuSC6H4CO2Os(CH═CH-bpyReCl(CO)3)(CO)(PPh3)2}2]. The same stepwise approach provides the dinuclear organometallic complexes [(L)Au(SC6H4CO2-4)M(CH═CHC6H4Me-4)(CO)(PPh3)2] (M = Ru, Os; L = PPh3, IDip). Complexes containing three metals from different groups of the periodic table [(L)Au(SC6H4CO2-4)M{CH═CH-bpyReCl(CO)3}(CO)(PPh3)2] (M = Ru, Os) can also be prepared, with one ruthenium example (L = PPh3) being structurally characterized. In order to illustrate the versatility of this approach, the synthesis and characterization (IR and NMR spectroscopy, TEM, EDS, and TGA) of the functionalized gold and palladium nanoparticles Au@[SC6H4CO2Ru(dppm)2]+ and Pd@[SC6H4CO2Ru(dppm)2]+ is reported.

Multimetallic systems composed of CpFe(CO)2-, Cp2Re- and (RCO2)2Bi- moieties

The reaction of [Fp]2 (Fp = (η5-C5H5)(CO)2Fe) with bismuth formate was shown to proceed via Fe-Bi bond formation yielding [Fp–Bi(O2CH)2]n, 1, that could be crystallized in form of two polymorphs. These differ in the way the [Fp−Bi(O2CH)2] units are connected via bridging formate ligands to yield the respective coordination polymers. The acetate derivative [Fp–Bi(O2CCH3)2] was used as a precursor compound targeting at the construction of an additional transition metal-bismuth bond: the reaction of [Fp–Bi(O2CCH3)2] with [Cp2ReH] likely yields in the envisaged complex [Fp−Bi(O2CCH3)ReCp2] first but then undergoes further transformation due to the presence of chloride and acetic acid in solution, which lead to the formation of [Fp−Bi(Cl)ReCp2], 3, and [Cp2Re–Bi(O2CCH3)2], 4, respectively. The identity of the heterotrimetallic compound 3 was established by a single-crystal X-ray diffraction analysis, while an independent synthetic route (reaction of [Cp2ReH] with [Bi(O2CCH3)3]) was developed for 4 in order to unambiguously identify 4 also as the product of the reaction between [Fp–Bi(O2CCH3)2] and [Cp2ReH].

Mono‐Oxido‐Bridged Heterobimetallic and Heterotrimetallic Compounds Containing Titanium(IV) and Chromium(III)

AbstractA series of oxido‐bridged heterobi‐ and heterotrimetallic complexes, [(tmtaa)Ti=O→Cr(Por)Cl] and [(tmtaa)Ti=O→Cr(Por)←O=Ti(tmtaa)]+ (tmtaa = 7,16‐dihydro‐6,8,15,17‐tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine; Por = 5,10,15,20‐tetraarylporphyrin), have been synthesized. To the best of our knowledge, these complexes are the first structurally characterized examples to contain a Ti=O→Cr or Ti=O→Cr←O=Ti structural motif. Crystal structures of representative heterobimetallic compounds, including the Ti=O→Cr binuclear complex 2 and two separate trimers, [Ti=O→Cr←O=Ti]SbF6 (10) and [Ti=O→Cr←O=Ti]Cl (12), are reported. The bi‐ and trimetallic molecules have similar structural parameters, including Ti–O, Cr–O, and Ti–O–Cr bond lengths and angles with a linear Ti=O→Cr geometry. Magnetic studies showed that a high‐spin CrIII (S = 3/2) center is present in both the bi‐ and trinuclear molecules. The redox potentials for CrIV/III (ΔE = 320 mV) and Por/Por·– (ΔE = 260 mV) can be tuned by modifying the porphyrin ligand. By determining the thermodynamics and kinetics of the formation of these complexes by titration experiments and electrochemistry, it was found that the bi‐ and trimetallic species undergo isomerization in solution, allowing easy substitution of the apical chlorido ligand.

Heterometallic multiple bonding: delocalized three-center σ and π bonding in chains of 4d and 5d transition metals.

Heterotrimetallic compounds Mo2Ru(dpa)4Cl2 (1) and W2Ru(dpa)4Cl2 (2) are prepared by reactions of M2(dpa)4 (M = Mo or W; dpa = 2,2'-dipyridylamide) with [Ru(CO)3Cl2]2. Crystallographic studies reveal short Mo-Ru and W-Ru distances, 2.38 Å (1) and 2.39 Å (2), suggestive of delocalized Mo-Mo-Ru and W-W-Ru bonding. In contrast to the σ bonding found in the corresponding iron compounds, density functional theory calculations reveal both a three-center/two-electron σ bond and two three-center/four-electron π bonds in the M-M-Ru compounds.

Homo- and Heterometal Complexes of Oxido–Metal Ions with a Triangular [V(V)O–MO–V(V)O] [M = V(IV) and Re(V)] Core: Reporting Mixed-Oxidation Oxido–Vanadium(V/IV/V) Compounds with Valence Trapped Structures

A new family of trinuclear homo- and heterometal complexes with a triangular [V(V)O-MO-V(V)O] (M = V(IV), 1 and 2; Re(V), 3] all-oxido-metal core have been synthesized following a single-pot protocol using compartmental Schiff-base ligands, N,N'-bis(3-hydroxysalicylidene)-diiminoalkanes/arene (H4L(1)-H4L(3)). The upper compartment of these ligands with N2O2 donor combination (Salen-type) contains either a V(IV) or a Re(V) center, while the lower compartment with O4 donor set accommodates two V(V) centers, stabilized by a terminal and a couple of bridging methoxido ligands. The compounds have been characterized by single-crystal X-ray diffraction analyses, which reveal octahedral geometry for all three metal centers in 1-3. Compound 1 crystallizes in a monoclinic space group P2(1)/c, while both 2 and 3 have more symmetric structures with orthorhombic space group Pnma that renders the vanadium(V) centers in these compounds exactly identical. In DMF solution, compound 1 displays an 8-line EPR at room temperature with <g> and <A> values of 1.972 and 86.61 × 10(-4) cm(-1), respectively. High-resolution X-ray photoelectron spectrum (XPS) of this compound shows a couple of bands at 515.14 and 522.14 eV due to vanadium 2p(3/2) and 2p(1/2) electrons in the oxidation states +5 and +4, respectively. All of these, together with bond valence sum (BVS) calculation, confirm the trapped-valence nature of mixed-oxidation in compounds 1 and 2. Electrochemically, compound 1 undergoes two one-electron oxidations at E(1/2) = 0.52 and 0.83 V vs Ag/AgCl reference. While the former is due to a metal-based V(IV/V) oxidation, the latter one at higher potential is most likely due to a ligand-based process involving one of the catecholate centers. A larger cavity size in the upper compartment of the ligand H4L(3) is spacious enough to accommodate Re(V) with larger size to generate a rare type of all-oxido heterotrimetallic compound (3) as established by X-ray crystallography.

Structural variations in the coordination chemistry of amine-bis(phenolate) cobalt(II/III) complexes

A series of cobalt(II), cobalt(III) and mixed valence cobalt(II/III) compounds has been prepared and characterized. The protonated tripodal tetradentate ligand precursors (dimethylaminoethylamino-N,N-bis(2-methylene-4-tert-butyl-6-methylphenol), H2[O2NN′]BuMeNMe2, dimethylaminoethylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol), H2[O2NN′]BuBuNMe2, and 2-pyridylamino-N,N-bis(2-methylene-4-tert-butyl-6-methylphenol), H2[O2NN′]BuMePy were reacted with cobaltous acetate tetrahydrate under varying conditions to afford a range of monometallic, bimetallic and trimetallic species. Monometallic compounds, 1 and 2, were obtained with pendant amine-containing ligands [O2NN′]BuMeNMe2 and [O2NN′]BuBuNMe2, respectively. Compound 1 is a trigonal bipyramidal CoII acetone adduct, CoII(OCMe2)[O2NN′]BuMeNMe2, and 2 is a distorted octahedral CoIII acetate complex, CoII(OAc)[O2NN′]BuBuNMe2. A dimethoxo-bridged dicobalt(III) complex, 3, was obtained using the pyridyl group-containing ligand, [O2NN′]BuMePy, after oxidation in air of a methanol solution of {Co[O2NN′]BuMePy}2. Two side-products, 4 and 5 were also obtained from this reaction. Complex 4 contains two octahedrally coordinated cobalt(III) atoms, each bonded to a tetradentate amine-bis(phenolate) ligand and bridged by one syn,syn η1:η1:μ2 acetate ligand, and one hydroxide ligand. Complex 5 is a heterotrimetallic compound and consists of two Co[O2NN′]BuMePy fragments, each bridged by a syn,anti η1:η1:μ2 acetate ligand to a central CaII(HOMe)4 fragment. Mixed valence CoIII–CoII–CoIII trimetallic complexes, 6 and 7, were obtained by reaction of H2[O2NN′]BuMePy or H2[O2NN′]BuBuPy ligands, respectively, with Co(OAc)2·4H2O in 2:3 molar ratios in methanol under nitrogen followed by aerobic oxidation. Diethylaminoethylamino-N,N-bis(2-methylene-4,6-di-tert-amylphenol), H2[O2NN′]AmAmNEt2 was reacted with cobaltous chloride hexahydrate under acidic conditions to give the ionic compound {H3[O2NN′]AmAmNEt2}+2[CoCl4]2−, 8.

Heterotrimetallic compounds containing Mo–M–Li [M = K, Rb and Cs] clusters: synthesis, structure, bonding, aromaticity and theoretical investigations of Li2M2 [M = K and Rb] and Cs4 rings

A new polydentate fac-trioxo molybdenum complex, [MoO(3)L](3-) {LH(3) = nitrilotriacetic acid}, has been synthesized by the reaction of lithium molybdate with iminodiacetic acid. The trinegative complex anion coordinates the alkali metal cations, K(+), Rb(+) or Cs(+). The potassium, rubidium and cesium complexes, [Li{K(H(2)O)(2)}MoO(3)L](n) (1), [Li{Rb(H(2)O)(2)}MoO(3)L](n) (2) and [Cs{Li(H(2)O)}(2)MoO(3)L](n) (3), form heterotrimetallic coordination chains, containing planar rings of Li(2)M(2) (M = K or Rb) and Cs(4). Theoretical investigations on these rings were carried out using NICS calculations and ab initio ring current maps, revealing aromaticity to be of limited significance.

Self-assembly of d-penicillaminato M6M′8 (M = Niii, Pdii, Ptii; M′ = Cui, Agi) clusters and their organization into extended LaiiiM6M′8 supramolecular structures

A series of chiral M(6)M'(8) cluster compounds having twelve free carboxylate groups, [M(6)M'(8)(D-pen-N,S)(12)X](5-) (M/M'/X = Pd(II)/Ag(I)/Cl(-) ([1](5-)), Pd(II)/Ag(I)/Br(-) ([2](5-)), Pd(II)/Ag(I)/I(-) ([3](5-)), Ni(II)/Ag(I)/Cl(-) ([4](5-)), Pt(II)/Ag(I)/Cl(-) ([5](5-)), Pd(II)/Cu(I)/Cl(-) ([6](5-)); D-H(2)pen = D-penicillamine), in which six cis-[M(D-pen-N,S)(2)](2-) square-planar units are bound to a [M'(8)X](7+) cubic core through sulfur-bridges, was synthesized by the reactions of cis-[M(D-pen-N,S)(2)](2-) with M' in water in the presence of halide ions. These M(6)M'(8) clusters readily reacted with La(3+) in aqueous buffer to form La(III)(2)M(6)M'(8) heterotrimetallic compounds, La(2)[1](CH(3)COO), La(2)[2](CH(3)COO), La(2)[3](CH(3)COO), La(2)[4](CH(3)COO), La(2)[5](CH(3)COO) and La(2)[6]Cl, in which the M(6)M'(8) cluster units are linked by La(3+) ions through carboxylate groups in a 1 : 2 ratio. While the La(III)(2)M(6)Ag(I)(8) compounds derived from [1](5-), [2](5-), [3](5-), [4](5-) and [5](5-) have a 1D helix supramolecular structure with a right-handedness, the La(III)(2)Pd(II)(6)Cu(I)(8) compound derived from [6](5-) has a 2D sheet-like structure with a triangular grid of the Pd(II)(6)Cu(I)(8) cluster units. When aqueous HCl was added to the reaction solution of [6](5-) and La(3+), another La(III)(2)Pd(II)(6)Cu(I)(8) heterotrimetallic compound, La(2)[6]Cl·HCl, in which the Pd(II)(6)Cu(I)(8) cluster units are linked by La(3+) ions to form a 2D structure with a rectangular grid, was produced. The solid-state structures of these La(III)(2)M(6)M'(8) compounds, determined by single-crystal X-ray crystallography, along with the spectroscopic properties of the M(6)M'(8) cluster compounds in solution, are described.

Synthesis, crystal structures and magnetic properties of two three-dimensional heterotrimetallic compounds [Cu(en)2Li(H2O)][Fe(CN)6] and [Cu(en)2Li(H2O)][Co(CN)6] (en = ethylenediamine)

Abstract Two heterotrimetallic compounds, [Cu(en)2Li(H2O)][Fe(CN)6] and [Cu(en)2Li(H2O)][Co(CN)6] (en = ethylenediamine), were synthesized and characterized. They are isostructural and crystallize in the orthorhombic space group Pbca at 293 K. The structures of the two compounds are composed of one-dimensional zigzag Fe/Co–C≡N–Cu chains linked by Li(I) ions into three-dimensional frameworks. Magnetic study of [Cu(en)2Li(H2O)][Fe(CN)6] reveals a weak magnetic interaction in the compound.

Reversible Opening of the Triangular Structure of a Sulfido-Bridged ZrRh2 Early−Late Heterobimetallic Complex Induced by Bis-(diphenylphosphino)methane

Reaction of the early−late heterobimetallic complexes [Cptt2Zr(μ3-S)2{M(CO)}2(μ-dppm)] (M = Rh, Ir) with dppm (bis-(diphenylphosphino)methane) yields the compounds [Cptt2Zr(μ-S)2M(μ-CO)2(μ-dppm)M(η2-dppm)] (M = Rh (3), Ir (4)). The molecular structure of 3 shows a bent trimetallic ZrRhRh chain with tetrahedral, trigonal-bipyramidal, and square-pyramidal geometries, respectively. This trinuclear compound exhibits a mixed-valence Rh(II)−Rh(0) metal−metal bonded unit that results from the unusual chelating coordination of the metalloligand [Cptt2Zr(S)2]2- and is further stabilized by the presence of two unsymmetrical bridging carbonyl ligands, which interact with the unsaturated Rh(II) metal. The formation of 3 is reversible, and the equilibrium 1 + dppm ⇆ 3 has been observed in solution (K ≈ 16 at 22 °C in C6D6). The opening of the triangular core in the heterotrimetallic compound [Cptt2Zr(μ3-S)2{Rh(CO)}{Ir(CO)}(μ-dppm)] (5) is not selective and gives the compounds [Cptt2Zr(μ-S)2Rh(μ-CO)2(μ-dppm)Ir(η2-dppm)] (6) and [Cptt2Zr(μ-S)2Ir(μ-CO)2(μ-dppm)Rh(η2-dppm)] (7) in a 3:1 molar ratio.

165 POSTER Furan ring-opened 17-hydroxywortmannin analogs as phcsphoinositide 3-kinase inhibitors active in human tumor xenograft models

A series of cobalt(II), cobalt(III) and mixed valence cobalt(II/III) compounds has been prepared and characterized. The protonated tripodal tetradentate ligand precursors (dimethylaminoethylamino-N,N-bis(2-methylene-4-tert-butyl-6-methylphenol), H2[O2NN′]BuMeNMe2, dimethylaminoethylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol), H2[O2NN′]BuBuNMe2, and 2-pyridylamino-N,N-bis(2-methylene-4-tert-butyl-6-methylphenol), H2[O2NN′]BuMePy were reacted with cobaltous acetate tetrahydrate under varying conditions to afford a range of monometallic, bimetallic and trimetallic species. Monometallic compounds, 1 and 2, were obtained with pendant amine-containing ligands [O2NN′]BuMeNMe2 and [O2NN′]BuBuNMe2, respectively. Compound 1 is a trigonal bipyramidal CoII acetone adduct, CoII(OCMe2)[O2NN′]BuMeNMe2, and 2 is a distorted octahedral CoIII acetate complex, CoII(OAc)[O2NN′]BuBuNMe2. A dimethoxo-bridged dicobalt(III) complex, 3, was obtained using the pyridyl group-containing ligand, [O2NN′]BuMePy, after oxidation in air of a methanol solution of {Co[O2NN′]BuMePy}2. Two side-products, 4 and 5 were also obtained from this reaction. Complex 4 contains two octahedrally coordinated cobalt(III) atoms, each bonded to a tetradentate amine-bis(phenolate) ligand and bridged by one syn,syn η1:η1:μ2 acetate ligand, and one hydroxide ligand. Complex 5 is a heterotrimetallic compound and consists of two Co[O2NN′]BuMePy fragments, each bridged by a syn,anti η1:η1:μ2 acetate ligand to a central CaII(HOMe)4 fragment. Mixed valence CoIII–CoII–CoIII trimetallic complexes, 6 and 7, were obtained by reaction of H2[O2NN′]BuMePy or H2[O2NN′]BuBuPy ligands, respectively, with Co(OAc)2·4H2O in 2:3 molar ratios in methanol under nitrogen followed by aerobic oxidation. Diethylaminoethylamino-N,N-bis(2-methylene-4,6-di-tert-amylphenol), H2[O2NN′]AmAmNEt2 was reacted with cobaltous chloride hexahydrate under acidic conditions to give the ionic compound {H3[O2NN′]AmAmNEt2}+2[CoCl4]2−, 8.

Direct synthesis and crystal structures of new heteropolynuclear complexes containing aminoalcohol ligands: From heterobi- (Co/Zn) to heterotrimetallic (Cu/Co/Zn) compounds

Three novel heterometallic complexes [Co 2Zn 2(Dea) 2(HDea) 2(NCS) 4] · 4dmso ( 1), [CuCoZn 2(Dea) 3Cl 3(HOMe)] · MeOH ( 2) and [CuCoZn(Me 2Ea) 4(NCS) 2(OAc)] ( 3) have been prepared from zerovalent zinc, cobalt thiocyanate and a dimethylsulfoxide solution of diethanolamine ( 1), zerovalent copper, cobalt chloride, zinc chloride and a methanol solution of diethanolamine ( 2), zerovalent copper, cobalt thiocyanate, zinc acetate and an acetonitrile solution of 2-(dimethylamino)ethanol in air ( 3) [H 2Dea is diethanolamine and HMe 2Ea is 2-(dimethylamino)ethanol]. The structures of all complexes were determined by single crystal X-ray analysis. Compound 1 consists of a centrosymmetric molecule based on a Co 2Zn 2O 6 core. In contrast to 1, the coordination cores of the structures of the heterotrimetallic complexes, CuCoZn 2O 6 (for 2) and CuCoZnO 4 (for 3) have no inversion centre. Both 2 and 3 possess a similar CuCoZnO 4 fragment that can be viewed as an incomplete distorted cube.