Cl Ligands Research Articles

Crystal and mol-ecular structures of di-chlorido-palladium(II) containing 2-methyl- or 2-phenyl-8-(diphenyphosphan-yl)quinoline.

The crystal structures of di-chlorido-palladium(II) complexes bearing 2-methyl- and 2-phenyl-8-(di-phenyl-phosphan-yl)quinoline, namely, di-chlorido-[8-(di-phenyl-phosphan-yl)-2-methyl-quinoline-κ2 N,P]palladium(II), [PdCl2(C22H18NP)] (1) and di-chlorido-[8-(di-phenyl-phosphan-yl)-2-phenyl-quinoline-κ2 N,P]palladium(II), [PdCl2(C27H20NP)] (2), were analyzed and compared to that of the 8-(di-phenyl-phosphan-yl)quinoline (PQH) analogue (3). In all three complexes, the phosphanyl-quinoline moiety acts as a bidentate P,N-donating chelate ligand. In the PQH complex (3), the PdII center has a typical planar coordination environment; however, both the methyl- and phenyl-substituted phosphanyl-quinoline (PQMe and PQPh, respectively) complexes (1) and (2) exhibit a considerable tetra-hedral distortion around the PdII center, as parameterized by the τ4 values of 0.1555 (4) and 0.1438 (4) for (1) and (2), respectively. The steric inter-action from the substituted group introduced at the 2-position of the quinoline ring enforces the cis-positioned Cl ligand to be displaced from the ideal coordination plane. Also, the ideally planar phosphanyl-quinoline five-membered chelate ring shows a large bending deformation by the displacement of the PdII center from the quinoline plane. In addition, in the phenyl-substituted complex (3), the coordinating quinolyl and the substituted phenyl rings are not co-planar to each other, having a dihedral angle of 33.08 (7)°. This twist conformation prohibits any inter-molecular π-π stacking inter-action between the quinoline planes, which is observed in the crystals of complexes (1) and (2).

Preparation, spectral, structural and hirshfeld surface analysis of a new organic-inorganic compound (C5H7N2).[ZnCl3(C5H6N2)

Single crystals of organic-inorganic hybrid compound (C5H7N2).[ZnCl3(C5H6N2)] was synthesized by slow evaporation method at room temperature and characterized byX-ray diffraction analysis, UV-visible, infrared spectroscopy (FTIR) and thermal analysis (TGA and DTA).This complex crystallizes in the triclinic system, space group P1¯. The unit cell parameters are a = 8.164 (4) Å, b = 9.196 (5), Å, c = 10.892 (6) Å, α = 89.25 (2)°, β = 86.23 (2)°, ɤ = 63.87 (2)°, Z = 2 and V =732.5 (6) Å3.The asymmetric unit of the title compound containsa distorted tetrahedral [ZnCl3(C5H6N2)]−1 anion and one protonated 2-Aminopyridinium cation. The Zn(II) ion is coordinated by three chloro ligands (Cl) and one nitrogen belonging to 2-aminopyridine ligand building a distorted tetrahedron.The supramolecular compound exhibits a three-dimensional solid state structure resulting from the interconnection of molecules through N–H···Cl, C–H···Cl hydrogen bonds and π–π stacking interactions.

Selective synthesis of mono(amidinate) chromium(II) chloride complexes and a computational insight of their interaction with human insulin

Treatment of one equivalent of sterically bulky lithiated amidinate ligands, [RC(NHAr)(NAr)] {R = Ph and Ar = 2,6-diisopropylphenyl (1); R = t-Bu and Ar = 2,6-diisopropylphenyl (2)}, with anhydrous chromium(II) chloride in tetrahydrofuran (THF) afforded, after workup in pentane or hexane, selectively rare examples of mono(amidinate) Cr(II) complexes, [{PhC(NAr)2}Cr(µ-Cl)(thf)]2 (3) and [{t-BuC(NAr)2}Cr(µ-Cl)]2 (4) in 48 and 45% yields, respectively. X-ray analysis shows both 3 and 4 to be dimeric with the amidinate ligands η2-coordinated to one Cr atom each and the Cl ligands bridge the two Cr centers. Owing to the low steric bulk of the amidinate ligand in 3, one thf ligand is coordinated to each Cr atom. A sterically less bulky ligand, [RC(NHAr)(NAr)] {R = t-Bu and Ar = 2,6-dimethylphenyl (5)} instead led to a bis(amidinate) Cr(II) complex (6). A molecular docking simulation of the ligands and metal ligated complexes was performed with the human insulin protein (PDB code: 3Q6E.) to gauge the potential of the metal complexes as effective drug candidates for the treatment of type I and type II diabetes. Docking simulations of the ligands and metal complexes showed a strong binding inside the active site cleft. The docked poses showed important binding features, mostly because of the interactions due to the aromatic moieties of the amidinate ligands.

Crystal structure of bis-[(R,R)-1,2-(bi-naph-thyl-phospho-nito)ethane]-dichlorido-iron(II) di-chloro-methane disolvate.

In the title compound (systematic name: bis-{1,2-bis[12,14-dioxa-13-phospha-penta-cyclo-[13.8.0.02,11.03,8.018,23]tricosa-1(15),2(11),3(8),4,6,9,16,18(23),19,21-deca-en-13-yl]ethane}-dichlorido-iron(II) di-chloro-methane disolvate), [FeCl2(C42H28O4P2)2]·2CH2Cl2, the FeII ion lies on a crystallographic twofold rotation axis and is coordinated by four P atoms from two (R,R)-1,2-bis-(bi-naphthyl-phospho-n-ito)ethane (BPE) ligands and two Cl ligands in a distorted cis-FeCl2P4 octa-hedral coordination geometry. In the crystal, weak C-H⋯O and C-H⋯π inter-actions link the mol-ecules into layers lying parallel to (001). A weak intra-molecular C-H⋯O hydrogen bond is also observed. The asymmetric unit contains one CH2Cl2 solvent mol-ecule, which is disordered over two sets of site with refined occupancies in the ratio 0.700 (6):0.300 (6).

Structural characterization of the derivatives of bis{[2,6-(dimethylamino)methyl]phenyl} selenide with palladium(II) and mercury(II).

The intramolecularly coordinated homoleptic diorgano selenide bis{2,6-bis[(dimethylamino)methyl]phenyl} selenide, C24H38N4Se or R2Se, where R is 2,6-(Me2NCH2)2C6H3, 14, was synthesized and its ligation reactions with PdII and HgII precursors were explored. The reaction of 14 with SO2Cl2 and K2PdCl4 resulted in the formation of the meta C-H-activated dipalladated complex {μ-2,2'-bis[(dimethylamino)methyl]-4,4'-bis[(dimethylazaniumyl)methyl]-3,3'-selanediyldiphenyl-κ4C1,N2:C1',N2'}bis[dichloridopalladium(II)], [Pd2Cl4(C24H38N4Se)] or [{R(H)PdCl2}2Se], 15. On the other hand, when ligand 14 was reacted with HgCl2, the reaction afforded a dimercurated selenolate complex, {μ-bis{2,6-bis[(dimethylamino)methyl]benzeneselanolato-κ4N2,Se:Se,N6}-μ-chlorido-bis[chloridomercury(II)], [Hg2(C12H19N2Se)Cl3] or RSeHg2Cl3, 16, where two HgII ions are bridged by selenolate and chloride ligands. In palladium complex 15, there are two molecules located on crystallographic twofold axes and within each molecule the Pd moieties are related by symmetry, but there are still two independent Pd centers. Mercury complex 16 results from the cleavage of one of the Se-C bonds to form a bifurcated SeHg2 moiety with the formal charge on the Se atom being -1. In addition, one of the Cl ligands bridges the two Hg atoms and there are two terminal Hg-Cl bonds. Each Hg atom is in a distorted environment which can be best described as a T-shaped base with the bridging Cl atom in an apical position, with several angles close to 90° and with one angle much larger and closer to 180°.

Efficient NH3-based process to remove chlorine from electron beam deposited ruthenium produced from (\u03b73-C3H5)Ru(CO)3Cl

The fabrication of Ru nanostructures by focused electron beam induced deposition (FEBID) requires suitable precursor molecules and processes to obtain the pure metal. So far this is problematic because established organometallic Ru precursors contain large organic ligands, such as cyclopentadienyl anions, that tend to become embedded in the deposit during the FEBID process. Recently, (η3-C3H5)Ru(CO)3X (X = Cl, Br) has been proposed as an alternative precursor because CO can easily desorb under electron exposure. However, allyl and Cl ligands remain behind after electron irradiation and the removal of the halide requires extensive electron exposures. Auger electron spectroscopy is applied to demonstrate a postdeposition purification process in which NH3 is used as a reactant that enhances the removal of Cl from deposits formed by electron irradiation of thin condensed layers of (η3-C3H5)Ru(CO)3Cl. The loss of CO from the precursor during electron-induced decomposition enables a reaction between NH3 and the Cl ligands that produces HCl. The combined use of electron-stimulated desorption experiments and thermal desorption spectrometry further reveals that thermal reactions contribute to the loss of CO in the FEBID process but remove only minor amounts of the allyl and Cl ligands.

Structure-activity relationships for osmium(II) arene phenylazopyridine anticancer complexes functionalised with alkoxy and glycolic substituents

Twenty-four novel organometallic osmium(II) phenylazopyridine (AZPY) complexes have been synthesised and characterised; [Os(η6-arene)(5-RO-AZPY)X]Y, where arene = p-cym or bip, AZPY is functionalized with an alkoxyl (O-R, R = Me, Et, nPr, iPr, nBu) or glycolic (O-{CH2CH2O}nR*, n = 1–4, R* = H, Me, or Et) substituent on the pyridyl ring para to the azo-bond, X is a monodentate halido ligand (Cl, Br or I), and Y is a counter-anion (PF6−, CF3SO3− or IO3−). X-ray crystal structures of two complexes confirmed their ‘half-sandwich’ structures. Aqueous solubility depended on X, the AZPY substituents, arene, and Y. Iodido complexes are highly stable in water (X = I ⋙ Br > Cl), and exhibit the highest antiproliferative activity against A2780 (ovarian), MCF-7 (breast), SUNE1 (nasopharyngeal), and OE19 (oesophageal) cancer cells, some attaining nanomolar potency and good cancer-cell selectivity. Their activity and distinctive mechanism of action is discussed in relation to hydrophobicity (RP-HPLC capacity factor and Log Po/w), cellular accumulation, electrochemical reduction (activation of azo bond), cell cycle analysis, apoptosis and induction of reactive oxygen species (ROS). Two complexes show ca. 4× higher activity than cisplatin in the National Cancer Institute (NCI) 60-cell line five-dose screen. The COMPARE algorithm of their datasets reveals a strong correlation with one another, as well as anticancer agents olivomycin, phyllanthoside, bouvardin and gamitrinib, but only a weak correlation with cisplatin, indicative of a different mechanism of action.

Multiresponsive Spin Crossover Driven by Rotation of Tetraphenylborate Anion in an Iron(III) Complex

Dynamic molecular materials, which involve mechanical motions in crystals, usually exhibit tunable properties related to conformational polymorphs. Herein, we describe a solvent-free molecular crys...

Electrocatalytic CO2 Reduction to Formate with Molecular Fe(III) Complexes Containing Pendent Proton Relays.

Previously, we reported an iron(III) complex with 6,6'-([2,2'-bipyridine]-6,6'-diyl)bis(2,4-ditertbutyl-phenol) as a ligand (Fe(tbudhbpy)Cl, 1) as catalytically competent for the electrochemical reduction of CO2 to formate (Faradaic efficiency FEHCO2- = 68 ± 4%). In mechanistic experiments, an essential component was found to be a pre-equilibrium reaction involving the association of the proton donor with the catalyst, which preceded proton transfer to the Fe-bound O atoms upon reduction of the Fe center. Here, we report the synthesis, structural characterization, and reactivity of two iron(III) compounds with 6,6'-([2,2'-bipyridine]-6,6'-diyl)bis(2-methoxy-4-methylphenol) (mecrebpy[H]2, Fe(mecrebpy)Cl, 2) and 6,6'-([2,2'-bipyridine]-6,6'-diyl)bis(4-(tert-butyl)benzene-1,2-diol) (tbucatbpy[H]4, Fe(tbucatbpy), 3) as ligands, where pendent -OMe and -OH groups are poised to modify the protonation reaction involving the Fe-bound O atoms. Differences in selectivity and activity for the electrocatalytic reduction of carbon dioxide (CO2) to formate (HCO2-) between complexes 1-3 were assessed via cyclic voltammetry and controlled potential electrolysis (CPE) experiments in N,N-dimethylformamide. Mechanistic studies suggest that the O atoms in the secondary coordination sphere are important for relaying the exogenous proton donor to the active site through a preconcentration effect, which leads to the JHCO2- (partial catalytic current density for formate) increasing by 3.3-fold for 2 and 1.2-fold for 3 in comparison to the JHCO2- of 1. These results also suggest that there is a difference in the strength of the interaction between the pendent functional groups and the sacrificial proton donor between 2 and 3, resulting in quantifiable differences in catalytic activity and efficiency. CPE experiments demonstrate an increased FEHCO2- = 85 ± 2% for 2, whereas 3 had a lower FEHCO2- = 71 ± 3%, with CO and H2 generated as co-products in each case to reach mass balance. These results indicate that using secondary sphere moieties to modulate metal-ligand interactions and multisite electron and proton transfer reactivity in the primary coordination sphere through reactant preconcentration can be a powerful strategy for enhancing electrocatalytic activity and selectivity.

Insights into CO2 Adsorption in M–OH Functionalized MOFs

A series of benzotriazolate MOFs containing nucleophilic transition metal hydroxide (M–OH) groups has been synthesized to compare the effects of framework structure, metal composition, and method of postsynthetic ligand exchange (PSLE) on CO2 adsorption. Analogues of MFU-4 (1a/b-OH, [Zn5(OH)4(bbta)3], bbta2– = benzo-1,2,4,5-bistriazolate) and MFU-4l (2a/b-OH, [Zn5(OH)4(btdd)3], btdd2– = bis(1,2,3-triazolo)dibenzodioxin) were prepared by direct Cl–/OH– ligand exchange (a) or Cl–/HCO3– ligand exchange followed by thermal activation (b). A Ni/Zn heterobimetallic analogue of MFU-4l (2a/b-NiOH) was also synthesized to investigate the effect of metal identity. The products have been characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). All of the M–OH functionalized MOFs show steep CO2 adsorption at low partial pressures. However, materials synthesized using the direct Cl–/OH– ligand exchange method show greater low-pressure CO2 uptake than those prepared by Cl–/HCO3– PSLE. Notably, the small pore size in 1a/b-OH not only promotes stronger framework–CO2 interactions and higher CO2 uptake than 2a/b-OH but also results in slow adsorption kinetics. The Ni/Zn heterobimetallic analogue 2a-NiOH exhibits the greatest low-pressure CO2 capacity (1.70 mmol g–1 at 2.6 mbar) among the series. In situ DRIFTS studies reveal that both 2a-OH and 2a-NiOH contain weak Zn–OH binding sites that readily desorb CO2 at room temperature. However, 2a-NiOH also contains strong Ni–OH binding sites that are spectroscopically distinct and only desorb CO2 upon heating.

Crystal structure of trans-di-chlorido-(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ4 N)chromium(III) bis-(form-amide-κO)(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ4 N)chromium(III) bis-[tetra-chlorido-zincate(II)

The structure of the title compound, [CrCl2(C10H24N4)][Cr(HCONH2)2(C10H24N4)][ZnCl4]2 (C10H24N4 = 1,4,8,11-tetra-aza-cyclo-tetra-decane, cyclam; HCONH2 = formamide, fa), has been determined from synchrotron X-ray data. The asymmetric unit contains two independent halves of the [CrCl2(cyclam)]+ and [Cr(fa)(cyclam)]3+ cations, and one tetra-chlorido-zincate anion. In each complex cation, the CrIII ion is coordinated by the four N atoms of the cyclam ligand in the equatorial plane and two Cl ligands or two O-bonded formamide mol-ecules in a trans axial arrangement, displaying a distorted octa-hedral geometry with crystallographic inversion symmetry. The Cr-N(cyclam) bond lengths are in the range 2.061 (2) to 2.074 (2) Å, while the Cr-Cl and Cr-O(fa) bond distances are 2.3194 (7) and 1.9953 (19) Å, respectively. The macrocyclic cyclam moieties adopt the centrosymmetric trans-III conformation with six- and five-membered chelate rings in chair and gauche conformations. The crystal structure is stabilized by inter-molecular hydrogen bonds involving the NH or CH groups of cyclam and the NH2 group of coordinated formamide as donors, and Cl atoms of the ZnCl4 2- anion as acceptors.

Iridium(III)porphyrin arrays with tuneable photophysical properties.

The photophysical properties of iridium(III) porphyrins complexes with two different axial ligands (Cl(CO) and bipyridine (bpy)) in solution and in cellulose acetate polymer matrix were investigated. The axial ligands substitution was made aiming to evaluate the photophysical properties and the solubility in different solvents. Therefore, dissimilar from the free porphyrin, non-polar solvents (as toluene) favours the quantum yield of iridium(III)porphyrins and ligands with a more extended π-conjugated compound as bpy results in higher yields. Moreover, despite all the porphyrins reveals a negative solvatochromism, the substitution of Cl(CO) ligand by bpy ligand exhibits similar solubility either on non-polar or polar solvents. The observed photoluminescence (PL) at room temperature appears at NIR region in contrast to the previously reported iridium(III) porphyrins. Comparing with free porphyrin H2TTP, the red/NIR PL spectra of the iridium(III)porphyrins (either in solution and in the polymer matrix) reveals remarkable changes. Particularly, a more significative decrease of the red/NIR intensity ratio was detected for [Ir(ttp)(bpy)2] 2 where the maxima of the NIR emission can be adjusted under suitable excitation wavelength.

Synthesis and crystal structure of a phenolato, chlorido and end-on azido-cobridged tetranuclear copper(II) complex derived from 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol

A novel phenolato-, chlorido- and end-on azido-cobridged tetranuclear copper(II) complex, [Cu4(daemp)2Cl2(μ-Cl)2(μ1,1-N3)2(MeOH)2] (Hdaemp = 2-[(2-dimethylaminoethylimino)methyl]-4-methylphenol), was prepared and characterized by elemental analyses, IR and UV-Vis spectra, and single crystal X-ray diffraction study. The Schiff base ligands coordinate to the Cu atoms through phenolate O, imino N and amino N atoms. The adjacent Cu···Cu distances are 3.169(2) and 3.063(2) Å. Each Cu atom is in a square pyramidal coordination. The azido ligands link two Cu atoms with end-on bridging mode. There are two coordination modes for the Cl ligands, viz. terminal and bridging. In the crystal structure, the complex molecules are stack along the b axis.

One‐Pot Synthesis of New Organometallic Compounds with Platinum‐Carbon Bond

Organometallic compounds of platinum containing ortho metalated para‐nitro‐benzamidate or 1‐naphthalene‐methylamine have been prepared by one‐pot synthesis. The para‐nitro‐benzamidate [Pt{K2C,N‐pNO2‐C6H4C(O)NH}(R,R‐DACH)] (compound 2) was obtained starting from [PtCl2(R,R‐DACH)] and para‐nitro‐benzonitrile, which, in the reaction conditions, hydrolyzes to the corresponding amide and forms the dinuclear intermediate [Pt2{µ‐N,O‐pNO2‐C6H4C(O)NH}2(R,R‐DACH)2]SO4 (compound 1·SO4) with HH or HT arrangement of the two bridging amidato ligands. Compound 1·SO4, kept at 90 °C for few hours, transforms into 2. The ortho‐metalated PtII derivative with 1‐naphthalene‐methylamine [PtCl{K2C,N‐C10H6CH2NH2}(DMSO)] (3) was obtained by direct reaction of [PtCl2(DMSO)2] with the amine. Unlike compound 2 that has no labile ligands, compound 3 has Cl and DMSO ligands that can be released, allowing the formation of cross‐links with DNA. Oxidation of 3 to the PtIV counterpart was performed with PhICl2 (compound 4). Unexpectedly, although six‐coordinate complexes of PtIV are considered to be inert, 4 underwent spontaneous isomerization from the mer to the fac isomer. All compounds have been fully characterized by multinuclear NMR spectroscopy, which has enabled complete assignment of all proton resonances. In the case of compound 2, a single‐crystal X‐ray investigation was also performed, showing, with the only exception of the puckered cyclohexane ring, a complete planarity of the complex frame, which could favor an intercalative interaction with DNA.

Synthesis, crystal structure and magnetic properties of copper(II) complexes with 4-methyl-N-[2-[(E)-2-pyridyl[alkyl]iminomethyl]phenyl]benzenesulfamide ligands

Two types of copper(II) complexes CuL1Cl and CuL2COOCH3 with tetradentate 4-methyl-N-[2-[(E)-2-pyridylmethyliminomethyl]phenyl]benzene-sulfamide (L1) and 4-methyl-N-[2-[(E)-2-pyridylethyliminomethyl]phenyl]-benzenesulfamide (L2) ligands were synthesized. The complexes were characterized by elemental analysis, infrared and 1H NMR spectra, magnetochemical measurements, and single crystal X-ray diffraction. The Cu atoms in the complexes CuL1Cl and CuL2COOCH3 are coordinated by tosylamine N,O, imino N and pyridine N atoms of the Schiff base ligand, and one Cl or acetate ligand at the apex, thus forming the strongly distorted square-pyramidal or octahedral environment, respectively. Complexes CuL1Cl and CuL2COOCH3 are paramagnetic.

Syntheses and Characterization of a Pair of Isomers of Heteroleptic Bis(Bidentate) Ruthenium(II) Complexes with Two Different Monodentate Ligands.

Two isomers of heteroleptic bis(bidentate) ruthenium(II) complexes with dimethyl sulfoxide (dmso) and chloride ligands, trans(Cl,Nbpy )- and trans(Cl,NHdpa )-[Ru(bpy)Cl(dmso-S)(Hdpa)]+ (bpy: 2,2'-bipyridine; Hdpa: di-2-pyridylamine), are synthesized. This is the first report on the selective synthesis of a pair of isomers of cis-[Ru(L)(L')XY]n+ (L≠L': bidentate ligands; X≠Y: monodentate ligands). The structures of the ruthenium(II) complexes are clarified by means of X-ray crystallography, and the signals in the 1 H NMR spectra are assigned based on 1 H-1 H COSY spectra. The colors of the two isomers are clearly different in both the solid state and solution: the trans(Cl,Nbpy ) isomer has a deep red color, whereas the trans(Cl,NHdpa ) isomer is yellow. Although both complexes have intense absorption bands at λ≈440-450 nm, only the trans(Cl,Nbpy ) isomer has a shoulder band at λ≈550 nm. DFT calculations indicate that the LUMOs of both isomers are the π* orbitals in the bpy ligand, and that the LUMO level of the trans(Cl,Nbpy ) isomer is lower than that of the trans(Cl,NHdpa ) isomer due to the trans effect of the Cl ligand; thus resulting in the appearance of the shoulder band. The HOMO levels are almost the same in both isomers. The energy levels are experimentally supported by cyclic voltammograms, in which these isomers have different reduction potentials and similar oxidation potentials.

Geometrical and Electronic Structure, Stability, and Optical Absorption Spectra Comparisons between Thiolate- and Chloride-Stabilized Gold Nanoclusters.

Thiolate-stabilized gold nanoclusters have drawn significant attention for their extraordinary properties and their applications in many fields such as catalysis, sensing, biomedicine, etc. However, due to the size, complexity, and conformational flexibility of thiolate ligands, accurate structure prediction can be a challenge using computational approaches. Substitution of thiolate ligands with chloride ligands provides a possible alternative. In this work, the stabilities of a series of gold thiolate and chloride clusters with 1:1 stoichiometry (AunLn; L = SH, Cl; n = 2-9) and the analogs of some experimentally observed gold nanoclusters (AunLm; L = SH, Cl; n = 18-133) are examined, and binding energies, HOMO-LUMO gaps, and absorption spectra are determined using density functional theory (DFT). We observed that the optimized geometries of gold nanoclusters for both types of ligands converged to the same local minimum structure as the experimentally observed structures. The average binding energy per gold atom in gold clusters converges after Au4L4. The binding energies of chloride-stabilized gold clusters and nanoclusters average 87.5% and 95.7% of the binding energies of thiolate-stabilized systems for the clusters and nanoclusters, respectively. Typically, thiolates are found to be more stable than the chlorides. However, higher HOMO-LUMO gaps in Au2Cl2, Au38Cl24, and Au102Cl44 compared to their thiolate analogs suggest systems of particular interest for investigating the possible existence of chloride-based gold nanoclusters. Absorption spectra are very similar regardless of the ligand used. This study also demonstrates that in theoretical studies on large nanoclusters, complex thiolate ligands can be replaced by Cl ligands to predict structural and electronic properties with reasonable accuracy and reduced computational effort.

PF5 and PCl5 interacting with water – Comparative study at the molecular level

The isomeric structures formed by the interaction of PF5 and PCl5 with up to four water molecules were theoretically examined by employing the MP2 method and the aug-cc-pVDZ basis set. The additional effects of surrounding water molecules were approximated by employing the polarized continuum solvation model (PCM) within a self-consistent reaction field treatment. The calculations indicate that the global minimum resulting from the interaction of PF5 and one H2O molecule corresponds to the PF5–H2O adduct and remains the most stable isomer after addition of second and third H2O, whereas the presence of fourth H2O molecule renders the PF5OH−/H3O+/2H2O structure the most stable. On the contrary, the interaction of PCl5 and a single H2O molecule leads to the global minimum structure corresponding to the PCl3O phosphoryl chloride with two HCl moieties attached. The lowest energy isomers resulting from the interaction of PCl5 with two, three, and four H2O molecules indicate the tendency of PCl3O to subsequent replacement of the Cl ligands with OH groups resulting in formation of H3PO4 (with five surrounding HCl fragments) when the number of available H2O molecules is sufficient. The presence of the competitive isomers containing H3O+ fragments in the case of the PCl5 interacting with water molecules is also predicted and discussed.

Increasing Lewis acidity in perchlorophenyl derivatives of antimony

The improved synthesis of the homoleptic perchlorophenyl stibine (C6Cl5)3Sb (1a) has enabled us to obtain detailed spectroscopic and structural information. In contrast to the planar structure shown by the nitrogen homologue (C6Cl5)3N, the antimony compound 1a shows unmistakable pyramidal structure (C–Sb–C 100.9(2)°, av.) with slightly elongated Sb–C bonds (219.6(4) pm, av.) with respect to the non-chlorinated model compound Ph3Sb. The Sb–C bonds shorten upon oxidation, as it is found in the oxidized compound (C6Cl5)3SbCl2 (2a). A single isomer is stereoselectively obtained for this hypervalent compound 2a, namely that with the Cl ligands in axial positions. This neutral, hypervalent compound (2a) is found to dissociate chloride in the gas phase (MS) giving rise to the [(C6Cl5)3SbCl]+ cation (3a). According to theoretical calculations this cation should have nearly tetrahedral structure and behave as a Lewis superacid. The structural properties and Lewis acidity of compounds 1a–3a are compared with those calculated for their corresponding isoelectronic tin derivatives (1b–3b).

Extended Assemblies of Ru(bpy)(CO)2X2 (X = Cl, Br, I) Molecules Linked by 1,4-Diiodotetrafluoro-Benzene (DITFB) Halogen Bond Donors

The ruthenium carbonyl compounds, Ru(bpy)(CO)2X2 (X = Cl, Br or I) act as neutral halogen bond (XB) acceptors when co-crystallized with 1,4-diiodotetrafluoro-benzene (DITFB). The halogen bonding strength of the Ru-X⋅⋅⋅I halogen bonds follow the nucleophilic character of the halido ligand. The strongest halogen bond occurs between the chlorido ligand and the iodide atoms of the DITFB. All three halogen bonded complexes form polymeric assemblies in the solid state. In Ru(bpy)(CO)2Cl2⋅DITFB (1) and in Ru(bpy)(CO)2Br2⋅DITFB (2) both halido ligands are halogen bonded to only one DITFB donor. In Ru(bpy)(CO)2I2⋅DITFB (3) only one of the halido ligands is involved in halogen bonding acting as ditopic center for two DITFB donors. The polymeric structures of 1 and 2 are isomorphic wave-like single chain systems, while the iodine complexes form pairs of linear chains attached together with weak F⋅⋅⋅O≡C interactions between the closest neighbors. The stronger polarization of the iodide ligand compared to the Cl or Br ligands favors nearly linear C-I⋅⋅⋅I angles between the XB donor and the metal complex supporting the linear arrangement of the halogen bonded chain.