Sn-S and Ru-Ru bonds cleavage reactions between [Ph3SnS(CH2)3SSnPh3] and Ru3(CO)12: X-ray crystal structures of [Ph3SnS(CH2)3SSnPh3] and trans-[Ru(CO)4(SnPh3)2]

The organotin complex [Ph₃SnS(CH₂)₃SSnPh₃] (1) was synthesized by PdCl₂ catalyzed reaction between Ph₃SnCl and disodium-1,3-propanedithiolate which in turn was prepared from 1,2-propanedithiol and sodium in refluxing THF. Reaction of 1 with Ru₃(CO)₁₂ in refluxing THF affords the mononuclear complex trans-[Ru(CO)₄(SnPh₃)₂] (2) and the dinuclear complex [Ru₂(CO)₆(μ-κ²-SCH₂CH₂CH₂S)] (3) in 20 and 11% yields, respectively, formed by cleavage of Sn-S bond of the ligand and Ru-Ru bonds of the cluster. Treatment of pymSSnPPh₃ (pymS = pyrimidine-2-thiolate) with Ru₃(CO)₁₂ at 55-60 °C also gives 2 in 38% yield. Both 1 and 2 have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction analysis.     

Optimum conditions for lipase immobilization on chitosan-coated Fe3O4 nanoparticles

Magnetic Fe₃O₄-chitosan nanoparticles are prepared by the coagulation of an aqueous solution of chitosan with Fe₃O₄ nanoparticles. The characterization of Fe₃O₄-chitosan is analyzed by FTIR, FESEM, and SQUID magnetometry. The Fe₃O₄-chitosan nanoparticles are used for the covalent immobilization of lipase from Candida rugosa using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. The response surface methodology (RSM) was employed to search the optimal immobilization conditions and understand the significance of the factors affecting the immobilized lipase activity. Based on the ridge max analysis, the optimum immobilization conditions were immobilization time 2.14 h, pH 6.37, and enzyme/support ratio 0.73 (w/w); the highest activity obtained was 20 U/g Fe₃O₄-chitosan. After twenty repeated uses, the immobilized lipase retains over 83% of its original activity. The immobilized lipase shows better operational stability, including wider thermal and pH ranges, and remains stable after 13 days of storage at 25 °C.     

Tailoring size and structural distortion of Fe3O4 nanoparticles for the purification of contaminated water

Fe₃O₄ magnetic nanoparticles with different particle sizes were synthesized using two methods, i.e., a co-precipitation process and a polyol process, respectively. The atomic pair distribution analyses from the high-energy X-ray scattering data and TEM observations show that the two kinds of nanoparticles have different sizes and structural distortions. An average particle size of 6–8 nm with a narrow size distribution was observed for the nanoparticles prepared with the co-precipitation method. Magnetic measurements show that those particles are in ferromagnetic state with a saturation magnetization of 74.3 emu g⁻¹. For the particles synthesized with the polyol process, a mean diameter of 18–35 nm was observed with a saturation magnetization of 78.2 emu g⁻¹. Although both kinds of nanoparticles are well crystallized, an obviously higher structural distortion is evidenced for the co-precipitation processed nanoparticles. The synthesized Fe₃O₄ particles with different mean particle size were used for treating the wastewater contaminated with the metal ions, such as Ni(II), Cu(II), Cd(II) and Cr(VI). It is found that the adsorption capacity of Fe₃O₄ particles increased with decreasing the particle size or increasing the surface area. While the particle size was decreased to 8 nm, the Fe₃O₄ particles can absorb almost all of the above-mentioned metal ions in the contaminated water with the adsorption capacity of 34.93 mg/g, which is ∼7 times higher than that using the coarse particles. We attribute the extremely high adsorption capacity to the highly-distorted surface.     

Synthesis and characterization of three group 10 complexes containing nido-carborane diphosphine: [MCl(PPh3){7,8-(PPh2)2-7,8-C2B9H10}] (M = Ni, Pd, Pt)

Three group 10 complexes containing nido-carborane diphosphine, [NiCl(PPh₃){7,8-(PPh₂)₂-7,8-C₂B₉H₁₀}] (1), [PdCl(PPh₃){7,8-(PPh₂)₂-7,8-C₂B₉H₁₀}] · 1.25CH₂Cl₂ (2) and [PtCl(PPh₃){7,8-(PPh₂)₂-7,8-C₂B₉H₁₀}] · 2.5CH₂Cl₂ (3) have been synthesized by the reactions of [M(PPh₃)₂Cl₂] (M = Ni, Pd, Pt) with closo carborane diphosphine 1,2-(PPh₂)₂-1,2-C₂B₁₀H₁₀ in ethanol. For complex 3, it could also be obtained under solvothermal condition. All three complexes were characterized by elemental analysis, FT-IR, ¹H and ¹³C NMR spectroscopy and X-ray structure determination. Single crystal structures show that their structures are similar to each other. In each complex, the nido [7,8-(PPh₂)₂-7,8-C₂B₉H₁₀]⁻, which resulted from the degradation of the initial closo ligand 1,2-(PPh₂)₂-1,2-C₂B₁₀H₁₀ during the reaction process, was coordinated bidentately through the P atoms to M(II) ion, and this resulted in a stable five-membered chelating ring between the bis-diphosphine ligand and the metal. The coordination mode of the metal can be described as a slightly distorted square-planar, in which the remaining two positions were occupied by one Cl⁻ and one PPh₃ group.     

Synthesis and characterization of tetrairon-tungsten cluster complex containing a μ4, η-carbonyl ligand

Reaction of [(PPh₂C₅H₄)Cp₃Fe₄(CO)₄] (1) with (CO)₄W(CH₃CN)₂ at ambient temperature affords [(CO)₄W(PPh₂C₅H₄)Cp₃Fe₄(CO)₄] (2) as the major product, together with a small amount of [(CO)₅W(PPh₂C₅H₄)Cp₃Fe₄(CO)₄] (3). Compound 3 can be obtained in good yield by treating (CO)₅W(CH₃CN) with equal molar of 1, and reaction of 3 with Me₃NO in acetonitrile solvent produces 2 exclusively. The crystal structures of 2 and 3 have been determined by an X-ray diffraction study. Compound 2 contains an interesting μ₄, η²-CO ligand, where two electrons donated by the carbon atom are involved to bridge a Fe₃ face and two electrons from oxygen are donated to the tungsten(0) atom.     

Transesterification of sunflower oil to biodiesel on ZrO2 supported La2O3 catalyst

ZrO₂ supported La₂O₃ catalyst prepared by impregnation method was examined in the transesterification reaction of sunflower oil with methanol to produce biodiesel. It was found that the catalyst with 21 wt% loaded La₂O₃ and calcined at 600 °C showed the optimum activity. The basic property of the catalyst was studied by CO₂-TPD, and the results showed that the fatty acid methyl ester (FAME) yield was related to their basicity. The catalyst was also characterized by TG–DTA, XRD, FTIR, SEM and TEM, and the mechanism for the formation of basic sites was discussed. It was also found that the crystallite size of support ZrO₂ decreased by loading of La₂O₃, and the model of the solid-state reaction on the surface of La₂O₃/ZrO₂ catalyst was proposed. Besides, the influence of various reaction variables on the conversion was investigated.     

Reactions of the fac-[Re(CO)3] and [ReO] moieties with substituted benzothiazoles

The reaction of 2-(2-aminophenyl)benzothiazole (Habt) with [Re(CO)₅Br] led to the isolation of the rhenium(I) complex fac-[Re(Habt)(CO)₃Br] (1). With trans-[ReOCl₃(PPh₃)₂], the ligand Habt decomposed to form the oxofree rhenium(V) complex [Re(itp)₂Cl(PPh₃)] (2) (itp = 2-amidophenylthiolate). From the reaction of trans-[ReOBr₃(PPh₃)₂] with 2-(2-hydroxyphenyl)benzothiazole (Hhpd) the complex [Re^VOBr₂(hpd)(PPh₃)] (3) was obtained. Complexes 1-3 are stable and lipophilic. ¹H NMR and infrared assignments, as well as the X-ray crystal structures, of the complexes are reported.     

Efficiency enhancement of the electrocatalytic reduction of CO2: fac-[Re(v-bpy)(CO)3Cl] electropolymerized onto mesoporous TiO2 electrodes

As the greenhouse effect increases, the development of systems able to convert with high efficiency CO₂ to energetically rich molecules owns a crucial weight in the technological and environmental domain. As catalyst, rhenium complexes, of the type fac-[Re(L)(CO)₃Cl] (i.e. L = 2,2′-bipyridyl or 4,4′-bipyridyl), have attracted a large interest demonstrating promising catalytic properties. fac-[Re(v-bpy)(CO)₃Cl]-based polymer deposited onto a solid support has been already investigated as heterogeneous catalyst in the reduction of CO₂. Here, we deposited by electrochemical polymerization fac-[Re(v-bpy)(CO)₃Cl] onto a nanocrystalline TiO₂ film on glass and we investigated by cyclic voltammetry the properties of such heterogeneous catalyst in the electrochemical reduction of CO₂. We demonstrated that the nanoporous nature of the substrate allows to increase the two-dimensional number of redox sites per surface area and hence to get a significant enhancement of the catalytic yield.     

Heterometal cubane-type WFe3S4 and related clusters trigonally symmetrized with hydrotris(3,5-dimethylpyrazolyl)borate

The scope of formation and structures of tungsten-iron-sulfur clusters has been explored using reactions based on [(Tp*)WS₃]¹⁻ (1) as the ultimate precursor. The reaction system 1/FeCl₂/NaSEt/S affords the cubane cluster [(Tp*)WFe₃S₄Cl₃]¹⁻ (2), which with NaSEt is converted to [(Tp*)WFe₃S₄(SEt)₃]¹⁻ (3).Clusters 2 and 3 contain the cubane [WFe₃(μ₃-S)₄]³⁺ core.Complex 1 with FeCl₂/NaSEt forms [(Tp*)WFe₂S₃Cl₂(SEt)]¹⁻ (4) with the cuboidal [WFe₂(μ₂-S)₂(μ₃-S)(μ₂-SR)]²⁺ core.Treatment of 2 with excess Et₃P yields the edge-bridged double [(Tp*)₂W₂Fe₆S₈(PEt₃)₄] (5) with the [W₂Fe₆(μ₃-S)₆(μ₄-S)₂] core. Reaction of 2 with excess leads a mixture of products, from which [(Tp*)₂W₂Fe₅S₉Na(SH)(MeCN)]³⁻(6) was identified.This cluster, as closely related [(Tp)₂Mo₂Fe₆S₉(SH)₂]³⁻, exhibits a core topology [W₂Fe₅Na(μ₂-S)₂(μ₃-S)₆(μ₆-S)] very similar to the P^N cluster of nitrogenase. All reactions were carried out in acetonitrile. The structures of 2-6 were established crystallographically as Et₄N⁺ salts. In the cubane series, substitution of tungsten for molybdenum decreases the [MFe₃S₄]^3+/2+ redox potential by ca. 0.20 V but has a negligible effect on electron distribution. This work expands the small set of previously known weak-field W-Fe-S clusters, demonstrates the existence of tungsten-containing edge-bridged double cubanes and clusters with the P^N core topology, and introduces a new cuboidal core structure as found in 4 (Tp = hydrotris(pyrazolyl)borate, Tp* = hydrotris(3,5-dimethylpyrazolyl)borate).     

Reactions of Zr(C5H5)(6,6-dmch)(PMe3)2 and Zr(6,6-dmch)2(PMe3)2 (dmch=dimethylcyclohexadienyl) with CO and alkynes

The reactions of Zr(C₅H₅)(6,6-dmch)(PMe₃)₂ and Zr(6,6-dmch)₂(PMe₃)₂ (dmch=dimethylcyclohexadienyl) with CO lead to the selective replacement of one PMe₃ ligand by CO. Both carbonyl complexes have been structurally characterized. Additionally, the reaction of the latter complex with PhC₂SiMe₃ leads to a similar replacement of one PMe₃ ligand, involving simple coordination of the alkyne, rather than any coupling to the dmch ligand.     

Cobalt(III) complexes with linear hexadentate N6 or N4S2 donor set atoms providing pyridyl-amide-amine/thioether coordination

Two new cobalt(III) complexes of symmetric hexadentate ligand with N₆ [1,10-bis(2-picolinamide)-4,7-diazadecane (pycdpnen)] and N₄S₂ [1,8-bis(2-picolinamide)-3,6-dithiaoctane (pycdadt)] donor set atoms have been synthesized as perchlorate salts and characterized by spectroscopic methods. All two ligands with strong-field pyridylcarboxamido N donor stabilize Co(III) as demonstrated by the facile oxidation of the cobalt center. The structures of [Co(pycdpnenH₋₂)](ClO₄) (1) and [Co(pycdadtH₋₂)](ClO₄) · H₂O (2) investigated by COSY, HMBC, HMQC and NOESY NMR studies show that compounds 1 and 2 have the same geometrical configuration. The X-ray analysis reveals that complex 2 crystallizes in a orthorhombic space group Pccn. The cation [Co(pycdadtH₋₂)]⁺ is distorted octahedral with the two pyridyl groups in cis position.     

Synthetic and mechanistic studies on ruthenium dicarbonyl complexes containing PhP(CH2CH2CH2PCy2)2 (Cyttp) ligand

A synthetic and mechanistic study is reported on ligand substitution and other reactions of six-coordinate ruthenium(II) carbonyl complexes containing tridentate PhP(CH₂CH₂CH₂PCy₂)₂ (Cyttp). Carbonylation of cis-mer-Ru(OSO₂CF₃)₂(CO)(Cyttp) (1) affords [cis-mer-Ru(OSO₂CF₃)(CO)₂(Cyttp)]O₃SCF₃ (2(O₃SCF₃)) and, on longer reaction times, [cis-mer-Ru(solvent)(CO)₂(Cyttp)](O₃SCF₃)₂ (solvent = acetone, THF, methanol). 2(O₃SCF₃) reacts with each of NaF, LiCl, LiBr, NaI, and LiHBEt₃ to yield [cis-mer-RuX(CO)₂(Cyttp)]⁺ (X = F (3), Cl (4), Br (5), I (6), H (7)), isolated as 3-7(BPh₄). These conversions proceed with high stereospecificity to afford only a single isomer of the product that is assigned a structure in which the Ph group of Cyttp points toward the CO trans to X (anti when X = F, Cl, Br, or I; syn when X = H). Treatment of 2(O₃SCF₃) with NaOMe and CO generates the methoxycarbonyl complex [cis-mer-Ru(CO₂Me)(CO)₂(Cyttp)]⁺ (8), whereas addition of excess n-BuLi to 2(O₃SCF₃) in THF under CO affords mer-Ru(CO)₂(Cyttp) (9). The two ¹³C isotopomers [cis-mer-Ru(OSO₂CF₃)(CO)(¹³CO)(Cyttp)]O₃SCF₃ (2′(O₃SCF₃): ¹³CO trans to P_C; 2″(O₃SCF₃): ¹³CO cis to all P donors) were synthesized by appropriate adaptations of known transformations and used in mechanistic studies of reactions with each of LiHBEt₃, NaOMe/CO, and n-BuLi. Whereas LiHBEt₃ reacts with 2′(O₃SCF₃) and 2″(O₃SCF₃) to replace triflate by hydride without any scrambling of the carbonyl ligands, the corresponding reactions of NaOMe-CO are more complex. The methoxide combines with the CO cis to triflate in 2, and the resultant methoxycarbonyl ligand ends up positioned trans to the incoming CO in 8. A mechanism is proposed for this transformation. Finally, treatment of either 2′(O₃SCF₃) or 2″(O₃SCF₃) with an excess of n-BuLi leads to the formation of the same two ruthenium(0) isomers of mer-Ru(CO)(¹³CO)(Cyttp). These products represent, to our knowledge, the first example of a syn-anti pair of isomers of a five-coordinate metal complex.     

Processing of glutathionylcobalamin by a bovine B12 trafficking chaperone bCblC involved in intracellular B12 metabolism

Glutathionylcobalamin (GSCbl) is a biologically relevant vitamin B₁₂ derivative and contains glutathione as the upper axial ligand thought formation of a cobalt-sulfur bond. GSCbl has been shown to be an effective precursor of enzyme cofactors, however processing of the cobalamin in intracellular B₁₂ metabolism has not been fully elucidated. In this study, we discovered that bCblC, a bovine B₁₂ trafficking chaperone, catalyzes elimination of the glutathione ligand from GSCbl by using the reduced form of glutathione (GSH). Deglutathionylation products are base-off cob(II)alamin and glutathione disulfide, which are generated stoichiometrically to GSH. Although cob(I)alamin was not detected due to its instability, deglutathionylation is likely analogous to dealkylation of alkylcobalamins, which uses the thiolate of GSH for nucleophilic displacement. The catalytic turnover number for the deglutathionylation of GSCbl is ?1.62 ± 0.13 min⁻¹, which is, at least, an order of magnitude higher than that for elimination of upper axial ligands from other cobalamins. Considering the prevalence of GSH at millimolar concentrations in cells, our results explain the previous finding that GSCbl is more effective than other cobalamins for synthesis of enzyme cofactors.     

Kinetics and mechanisms of the CO2 and SO2 uptake by coordinate ion, cis-[Cr(C2O4)(L-L)(OH2)2] {(L-L) = methyl 3-amino-2,3-dideoxy-α-d-arabino-hexopyranoside} as studied by stopped-flow spectrophotometry

The kinetics of CO₂ and SO₂ uptake by a coordinate ion, cis-[Cr(C₂O₄)(L-L)(OH₂)₂]⁺, where L-L stands for a bidentate sugar ligand, methyl 3-amino-2,3-dideoxy-α-d-arabino-hexopyranoside has been studied, over temperature ranges of 5 - 25 and 5 - 20 °C for CO₂ and SO₂, respectively. Investigations were carried out using stopped-flow spectrophotometry in the range of 340-700 nm. Results of the kinetic measurements obtained for both gases were compared. The kinetics and mechanisms of the reactions were suggested and ΔH^‡ values for both processes were determined.     

Mono- and dinuclear Fe(III) complexes with the N2O2 donor 5-chlorosalicylideneimine ligands; synthesis, X-ray structural characterization and magnetic properties

Two novel monomeric [C₁₈H₁₇Cl₃N₂O₂Fe] (1) and dimeric [C₃₈H₃₆N₄O₄Cl₆Fe₂] (2) Fe(III) tetradentate Schiff base complexes have been synthesized and their crystal structures have been determined by single crystal X-ray diffraction analysis. In complex (1) the Schiff base ligand coordinates toward one iron atom in a tetradentate mode and each iron atom is five coordinated with the coordination geometry around iron atom which can be described as a distorted square pyramid. The presence of a short (2.89 Å) non-bonding interatomic Fe···O distances between adjacent monomeric Fe(III) complexes results in the formation of a dimer. Structural analysis of compound (2) shows that the structure is a centrosymmetric dimer in which the six coordinated Fe(III) atoms are linked by μ-phenoxo bridges from one of the phenolic oxygen atoms of each Schiff base ligand to the opposite metal center. The variable-temperature (2-300 K) magnetic susceptibility (χ) data of these two compounds have been investigated. The results show that for both complexes Fe(III) centers are in the high spin configuration (S = 5/2) and indicate antiferromagnetic spin-exchange interaction between Fe(III) ions. The obtained results are briefly discussed using magnetostructural correlations developed for other class of iron(III) complexes.     

Study on the heterogeneous degradation of chitosan with H2O2 catalyzed by a new supermolecular assembly crystal: [C6H8N2]6H3[PW12O40]·2H2O

A new supermolecular assembly crystal, [C₆H₈N₂]₆H₃[PW₁₂O₄₀]·2H₂O (DMB-PWA), was synthesized with phosphotungstic acid (PWA) and 1,2-diaminobenzene (DMB) under hydrothermal conditions and was characterized by Fourier-transform infrared spectra (FTIR) and single-crystal X-ray diffraction analysis. DMB-PWA could effectively catalyze oxidative degradation of chitosan with H₂O₂ in the heterogeneous phase. The optimum degradation conditions were determined by orthogonal tests as follows: amount of chitosan 1.00 g, 30% (wt %); H₂O₂, 3.0 mL; dosage of catalyst, 0.06 g; reaction temperature, 85 °C; and reaction time, 30 min. The water-soluble chitosan with a viscosity-average molecular weight (M_v) of 4900 was obtained under the optimum degradation conditions and was characterized by FTIR, ultraviolet-visible diffuse reflection spectra (UV-vis DRS), and X-ray powder diffraction analysis.     

Interactions between TGF-β1 and TGF-β3 and their role in medial edge epithelium cell death and palatal fusion in vitro

In recent decades, studies have shown that both TGF-β₁ and TGF-β₃ play an important role in the induction of medial edge epithelium (MEE) cell death and palatal fusion. Many of these experiments involved the addition or blockage of one of these growth factors in wild-type (WT) mouse palate cultures, where both TGF-β₁ and TGF-β₃ are present. Few studies have addressed the existence of interactions between TGF-β₁ and TGF-β₃, which could modify their individual roles in MEE cell death during palatal fusion. We carried out several experiments to test this possibility, and to investigate how this could influence TGF-β₁ and TGF-β₃ actions on MEE cell death and palatal shelf fusion. We double-immunolabelled developing mouse palates with anti-TGF-β₁ or anti-TGF-β₃ antibodies and TUNEL, added rhTGF-β₁ or rhTGF-β₃ or blocked the TGF-β₁ and TGF-β₃ action at different concentrations to WT or Tgf-β₃ null mutant palate cultures, performed in situ hybridizations with Tgf-β₁ or Tgf-β₃ riboprobes, and measured the presence of TUNEL-positive midline epithelial seam (MES) cells and MES disappearance (palatal shelf fusion) in the different in vitro conditions. By combining all these experiments, we demonstrate great interaction between TGF-β₁ and TGF-β₃ in the developing palate and confirm that TGF-β₃ has a more active role in MES cell death than TGF-β₁, although both are major inductors of MES disappearance. Finally, the co-localization of TGF-β₁, but not TGF-β₃, with TUNEL in the MES allows us to suggest a possible role for TGF-β₁ in MES apoptotic clearance.     

血红蛋白A2现象发生机制的研究——“红细胞HbA2”为HbA2与HbA的结合产物

为了弄清血红蛋白A₂现象的发生机制,我们对“红细胞HbA₂”的化学组成进行了分析。“红细胞HbA₂”的双向电泳结果表明,它含有两种血红蛋白成分:一种相当于HbA,另一种很可能是溶血液HbA₂。其单向二次电泳结果也证明,它是由溶血液HbA₂和HbA所组成。结果初步说明,盘红细胞中HbA₂可能与HbA结合存在。两者可能有相互作用,也许这是产生血红蛋白A₂现象的原因。     

Multinuclear magnetic resonance studies of the hydrolyzed and aquated species of the antitumor complexes cis-Pt(cyclobutylamine)2X2 and cis-Pt(NH3)(cyclobutylamine)X2 and antitumor testing of mixed-amine Pt(II) compounds

The aquated and hydrolyzed species formed from the complexes cis-Pt(cba)₂I₂ and cis-Pt(NH₃)(cba)I₂ (cba = cyclobutylamine) were studied by multinuclear (¹⁹⁵Pt, ¹⁵N and ¹H) magnetic resonance spectroscopy. The iodo ligands were removed with AgNO₃. In acidic medium, the aqueous product consists of the diaqua and the aqua-nitrato cations, although some monohydroxo-bridged dimers are formed after several hours, especially for the mixed-ligand compound. In basic medium, the main species are the dihydroxo compounds. At neutral pD, several species exist in solution, especially with the mixed-amine system, which contained also a small quantity of the symmetric cis-Pt(cba)₂ complexes. Difficulties were encountered because of the insolubility of several oligomeric species, contrary to the cis-Pt(NH₃)₂ system, probably due to the greater lipophilicity of cba compared to NH₃. Monohydroxo-bridged dimers are formed in large quantities and the stereochemistry of the mixed-amine species was determined by ¹⁵N NMR spectroscopy. For the latter system, the cyclic dihydroxo-bridged dimers are the predominant species at neutral pD after a few hours. After an extended period of time, most of the oligomers precipitate, leaving the more soluble monohydroxo-bridged dimers as the major species in solution. The preliminary antitumor testing results on several dichloro mixed-ligand compounds are listed. The results on further testing on the most active compound cis-Pt(NH₃)(cba)Cl₂ are also included.     

From U(IV) double-decker phthalocyanine with stacked UPc2 sandwiches to unstacked ones

The uranium diphthalocyanine complex with the composition of [UPc₂]·2DBU·(CH₃)₂CO has been obtained by recrystallisation of [UPc₂](I₃)_2/3 in DBU (1,8-diazabicyclo[4.5.0]undec-7-ene) during slow dilution with acetone. The [UPc₂]·2DBU·(CH₃)₂CO complex crystallises in the Pna2₁ space group of the orthorhombic system with four molecules in the unit cell. In contrast to the stacked structure of [UPc₂](I₃)_2/3 the structure of [UPc₂]·2DBU·(CH₃)₂CO contains separated and unstacked UPc₂ sandwiches. The [UPc₂]·2DBU·(CH₃)₂CO complex dissolved in benzene, in 1-choronaphthalene and in DBU has been characterised by the UV-Vis spectroscopy. Some remarks on the stability of the complex in these solutions as well as its transformation to uranium monophthalocyanine have been made.