Alkyliminophosphorsäuretrihalogenide, 1. Mitt.: Halogenaustausch zwischen (CH3NPCl3)2 und (CH3NPF3)2

Zusammenfassung Durch Reaktion von dimerem Methyliminophosphorsäuretrichlorid mit dimerem Methyliminophosphorsäuretrifluorid werden die gemischt halogenierten dimeren Methyliminophosphorsäuretrihalogenide der allgemeinen Zusammensetzung (CH₃NP)₂Cl _n F_6–n mitn=1–5 dargestellt. Die analytischen Daten und die IR-Spektren werden mitgeteilt.

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Alkylimino phosphoric acid trihalogenides, I.: Halogen exchange between (CH₃NPCl₃)₂ and (CH₃NPF₃)₂

The reaction of (CH₃NPCl₃)₂ and (CH₃NPF₃)₂ yields the unknown 1.3-diaza-2.4-fluorochloro-phosphetidines of the general formula (CH₃NP)₂Cl _n F_6–n withn=1–5. The synthesis, the analytical data and the IR-spectra are reported.

     

Comparative IR spectroscopic study of phosphorus-containing dendrimers built of thiophosphoryl, cyclophosphazene and phthalocyanine cores

The FTIR spectra of four generations of phosphorus-containing dendrimers built of thiophosphoryl, cyclophosphazene and phthalocyanine cores with terminal benzaldehyde and P–Cl groups have been recorded and analyzed. FT-Raman spectra of four generations of phosphorus dendrimers built of cyclotriphosphazene core with terminal benzaldehyde groups have been detected. Their spectral pattern is determined by the ratio T_n/R_n (T_n—number of terminal groups, R_n—number of repeating units). This ratio trends to r − 1 (r—branching functionality of repeating unit), and becomes constant, when the generation number is higher than 3. Experimental IR spectra of dendrimers built of thiophosphoryl, cyclophosphazene and phthalocyanine cores are very closely similar. The dependence of band full width at half height in IR spectra on the number of dendrons is established. The possibility appears to separate the bands assigned to the core, repeating units and terminal groups of dendrimers by difference spectroscopy method.     

A Photophysical Study of Terphenyl Core Oligosulfonimide Dendrimers Exhibiting High Steady‐State Anisotropy

The photophysical properties of three dendrimers containing a p‐terphenyl core with appended sulfonimide branches of different size and n‐octyl chains have been investigated in dichloromethane solution. In the dendrimer absorption spectra contributions from both the branches and the core are clearly identified. The fluorescence spectra show only the characteristic fluorescence of the terphenyl unit. Energy transfer from the appended chromophoric groups to the core does not occur. In the dendrimers, the terphenyl core exhibits a very high fluorescence quantum yield (ca. 0.75) and a short emission lifetime (0.8 ns). These properties allowed investigations of the fluorescence depolarization caused by rotation of the dendrimers. The dendrimers show a very high steady‐state anisotropy in dichloromethane solution at room temperature (0.24 for the largest one), compared to that of the parent terphenyl under the same experimental conditions (<0.01) and in rigid matrix (0.33). Both the n‐octyl chains and the sulfonimide branches play important roles to slow down the molecular rotation.     

A fullerene core to probe dendritic shielding effects

Dendrimers with a C₆₀ core have been obtained by cyclization of dendritic bis-malonate derivatives at the carbon sphere. The resulting bis-methanofullerene derivatives have been characterised by electrospray (ES) and/or MALDI-TOF mass spectrometries. UV-VIS absorption spectra, fluorescence spectra, and fullerene singlet excited state lifetimes have been determined in solvents of different polarity (toluene, dichloromethane, acetonitrile). These data suggest a tighter core/periphery contact upon increase of solvent polarity and dendrimer size. In all the investigated solvents, the fullerene triplet lifetimes are steadily increased with the dendrimer volume, reflecting lower diffusion rates of O₂ inside the dendrimers along the series. Measurements of quantum yields of singlet oxygen sensitization indicate that longer lived triplet states generate lower amounts of singlet oxygen (¹O₂^∗) in dichloromethane but not in apolar toluene suggesting a tighter contact between the dendritic branches and the fullerene core in CH₂Cl₂. In acetonitrile, the trend in singlet oxygen production is peculiar. Effectively, enhanced singlet oxygen production is monitored for the largest dendrimer. This reflects specific interactions of excited ¹O₂^∗ molecules with the dendritic wedges, as probed by singlet oxygen lifetime measurements, possibly as a consequence of trapping effects.     

Formation of helix-containing rods in a hybrid inorganic–organic material

The novel aluminum ethylenediphosphonate fluoride, [HN(CH₂CH₂NH₃)₃][Al₂(O₃PCH₂CH₂PO₃)₂F₂]·H₂O (1) (monoclinic, P2₁/n, a=12.145(4) Å, b=9.265(3) Å, c=20.422(6) Å, β=104.952(4)°, Z=3, R₁=0.092, wR₂=0.196) has been synthesized by solvothermal methods in the presence of tris(2-aminoethyl)amine and its structure determined using single microcrystal X-ray diffraction data. Compound 1 is a one-dimensional extended chain structure composed of well-separated anionic [Al₂(O₃PCH₂CH₂PO₃)₂F₂]⁴⁻ rods containing helical chains of corner-shared cis-AlO₄F₂ octahedra at their core. The charge-compensating tris(2-aminoethyl)ammonium cations separate the anionic [Al₂(O₃PCH₂CH₂PO₃)₂F₂]⁴⁻ rods that contain either left- or right-handed helical chains. The incorporation of the organic components into this hybrid material has aided the adoption of one-dimensionality by the compound and defined the pitch of the helical AlO₄F chain.     

Thermal study of some new quinolone ruthenium(III) complexes with potential cytostatic activity

A series of new complexes with mixed ligands of the type RuL _m (DMSO) _n Cl₃·xH₂O ((1) L: oxolinic acid (oxo), m = 1, n = 0, x = 4; (2) L: pipemidic acid (pip), m = 2, n = 1, x = 2; (3) L: enoxacin (enx), m = 2, n = 1, x = 0; (4) L: levofloxacin (levofx), m = 2, n = 2, x = 8; DMSO: dimethylsulfoxide) were synthesized and characterized by chemical analysis, IR and electronic data. Except oxolinic acid that behaves as bidentate, the other ligands (quinolone derivatives and DMSO) act as unidentate. Electronic spectra are in accordance with an octahedral stereochemistry. The thermal analysis (TG, DTA) in synthetic air flow elucidated the composition and also the number and nature of both water and DMSO molecules. The TG curves show 3–5 well-separated thermal steps. The first corresponds to the water and/or DMSO loss at lower temperatures followed either by quinolone thermal decomposition or pyrolisys at higher temperatures. The final product is ruthenium(IV) oxide.     

Copper formal oxidation states above +1 in organometallic chemistry: the possibility of synthesizing cyclopentadienylcopper chlorides by oxidative addition reactions

Although organometallic compounds of Cu(I) have been known for some time, including cyclopentadienyl derivatives of the type CpCuL (Cp = η⁵-cyclopentadienyl ligand; L = phosphine or CO), organometallic compounds of copper in higher formal oxidation states are essentially unknown except for a few alkylcopper(III) and allylcopper(III) derivatives, only stable at very low temperatures. Theoretical studies on the cyclopentadienyl derivatives Cp₂Cu₂Cl _n (n = 1, 2, 3) indicate a preference for structures with terminal Cp rings and bridging Cl atoms up to a maximum of two of the latter. However, Cp₂Cu₂Cl _n (n = 1, 2, 3) structures with bridging Cp rings are found at only slightly higher energies. The lowest energy doublet mixed Cu(II/III) oxidation state Cp₂Cu₂Cl₃ structure with a single bridging Cl atom can be formally derived from the lowest energy doublet Cu(I/II) mixed oxidation state Cp₂Cu₂Cl structure by oxidative addition of Cl₂.     

Rhodium or ruthenium units peripherally coordinated to carbosilane dendrimers functionalized with P-stereogenic monophosphines

Carbosilane dendrimers containing P-stereogenic monophosphines as terminal groups, Dend-{CH₂PPhR}_n (R = 2-biphenylyl or 9-phenanthryl), were reacted with [RhCl(COD)]₂ or [RuCl₂(p-cymene)]₂ to afford the corresponding chiral metalladendrimers Dend-{CH₂PPhR(RhCl(COD))}_n or Dend-{CH₂PPhR(RuCl₂(p-cymene))}_n, respectively. Attempts to obtain the first generation Ru-dendrimer for R = 2-biphenylyl proved unsuccessful, probably due to the steric hindrance of R. Complete characterization of these species was achieved by multinuclear NMR spectra, including 2D experiments, mass spectrometry, and optical rotation determinations. The catalytic properties of the rhodium dendrimers were tested in the hydrogenation of dimethylitaconate and those of the ruthenium derivatives in the asymmetric hydrogen transfer of acetophenone. The following model chiral compounds, (CH₃)₃Si{CH₂PPhR(RhCl(COD))} and (CH₃)₃Si{CH₂PPhR(RuCl₂(p-cymene))}, were prepared in order to detect potential dendritic effects. All compounds were active in the catalytic conditions tested, but low or null e.e. were found.     

Synthesis,crystal structure and nonlinear optical properties of a cluster compound containing the bipy ligand

The [MoO_0.75S_3.25Cu₃Cl(bipy)₂] complex was synthesized for nonlinear optical studies by the reaction of (NH₄)₂[MoOS₃], CuCl and bipy in CH₂Cl₂ solution. A single crystal X-ray analysis revealed that the complex consists of a nest-shaped core. The Mo atom is tetrahedrally coordinated by four S atoms, or three S atoms and one terminal O atom. There are two types of copper atom in the MoO_0.75S_3.25Cu₃ aggregate: two copper atoms are tetrahedrally coordinated and another copper atom is trigonally coordinated. The third-order nonlinear optical properties were investigated by the Z-scan technique with 8 ns laser pulses at 532 nm. The cluster exhibits both optical self-focusing and optical nonlinear absorption (effectively n ₂ = 1.3 × 10^–11 e.s.u., ₂ = 1.2 × 10^–10 m W^–1 in a 2.68 × 10^–4 mol dm^–3 CH₂Cl₂ solution).     

Cluster Compounds with Oxidised,Hexanuclear [Nb6Cli 12Ia 6] n− Anions (n=2 or 3)

Four mixed‐halide cluster salts with chloride‐iodide‐supported octahedral Nb₆ metal atoms cores were prepared and investigated. The cluster anions have the formula [Nb₆Clⁱ ₁₂I^a ₆] ⁿ⁻ with Cl occupying the inner ligand sites and I the outer one. They are one‐ or two‐electron‐oxidized (n=2 or 3) with respect to the starting material cluster. (Ph₄P)⁺ and (PPN)⁺ function as counter cations. The X‐ray structures reveal a mixed occupation of the outer sites for only one compound, (PPN)₃[Nb₆Clⁱ ₁₂I^a _5.047(9)Cl^a _0.953]. All four compounds are obtained in high yield. If in the chemical reactions a mixture of acetic anhydride, CH₂Cl₂, and trimethylsilyl iodide is used, the resulting acidic conditions lead to form the two‐electron‐oxidised species (n=2) with 14 cluster‐based electrons (CBEs). If only acetic anhydride is used, the 15 CBE species (n=3) is obtained in high yield. Interesting intermolecular bonding is found in (Ph₄P)₂[Nb₆Clⁱ ₁₂I^a ₆] ⋅ 4CH₂Cl₂ with I⋅⋅⋅I halogen bonding and π‐π bonding interactions between the phenyl rings of the cations in (PPN)₃[Nb₆Clⁱ ₁₂I^a _5.047(9)Cl^a _0.953]. The solubility of (Ph₄P)₂[Nb₆Clⁱ ₁₂I^a ₆] ⋅ 4CH₂Cl₂ has been determined qualitatively in a variety of solvents, and good solubility in the aprotic solvents CH₃CN, THF and CH₂Cl₂ has been found.     

Lithiated γ-O-functionalized propyl phenyl sulfides and sulfones of the type Li[CH(SOxPh)CH2CH2OR] (x = 0, 2). [Li{CH(SPh)CH2CH2Ot-Bu}(tmeda)] – A structurally characterized organolithium inner complex

Lithiation of O-functionalized alkyl phenyl sulfides PhSCH₂CH₂CH₂OR (R = Me, 1a; i-Pr, 1b; t-Bu, 1c; CPh₃, 1d) with n-BuLi/tmeda in n-pentane resulted in the formation of α- and ortho-lithiated compounds [Li{CH(SPh)CH₂CH₂OR}(tmeda)] (α-2a–d) and [Li{o-C₆H₄SCH₂CH₂CH₂OR)(tmeda)] (o-2a–d), respectively, which has been proved by subsequent reaction with n-Bu₃SnCl yielding the requisite stannylated γ-OR-functionalized propyl phenyl sulfides n-Bu₃SnCH(SPh)CH₂CH₂OR (α-3a–d) and n-Bu₃Sn(o-C₆H₄SCH₂CH₂CH₂OR) (o-3a–d). The α/ortho ratios were found to be dependent on the sterical demand of the substituent R. Stannylated alkyl phenyl sulfides α-3a–c were found to react with n-BuLi/tmeda and n-BuLi yielding the pure α-lithiated compounds α-2a–c and [Li{CH(SPh)CH₂CH₂OR}] (α-4a–b), respectively, as white to yellowish powders. Single-crystal X-ray diffraction analysis of [Li{CH(SPh)CH₂CH₂Ot-Bu}(tmeda)] (α-2c) exhibited a distorted tetrahedral coordination of lithium having a chelating tmeda ligand and a C,O coordinated organyl ligand. Thus, α-2c is a typical organolithium inner complex.Lithiation of O-functionalized alkyl phenyl sulfones PhSO₂CH₂CH₂CH₂OR (R = Me, 5a; i-Pr, 5b; CPh₃, 5c) with n-BuLi resulted in the exclusive formation of the α-lithiated products Li[CH(SO₂Ph)CH₂CH₂OR] (6a–c) that were found to react with n-Bu₃SnCl yielding the requisite α-stannylated compounds n-Bu₃SnCH(SO₂Ph)CH₂CH₂OR (7a–c). The identities of all lithium and tin compounds have been unambiguously proved by NMR spectroscopy (¹H, ¹³C, ¹¹⁹Sn).     

pH-Directed assembly and magnetic properties of two polynuclear Mn complexes: (Δ, Λ)-{Mn3(phen)2(OOCCH3)6} and 1-D [Mn(phen)Cl2]n

When the reaction conditions are deliberately controlled by the pH, two different polynuclear manganese complexes, (Δ, Λ)-{Mn₃(phen)₂ (CH₃COO)₆} (1) and [Mn(phen)Cl₂]_n (2) (phen = 1,10-phenanthroline), have been synthesized from the same raw materials. The structural analyses show that 1 has a structure formed by neutral chiral linear trinuclear molecules, while 2 has a structure consisting of one-dimensional infinite chains. A study of the temperature dependent magnetic susceptibilities reveal that 1 is an antiferromagnetically coupled trimer molecule while 2 shows ferromagnetic interactions within the chain.     

Na3RuD7 – Synthese und Struktur

Na₃RuD₇ – Synthesis and Structure Na₃RuD₇ was synthesized by the reaction of sodium deuteride with ruthenium powder under a hydrogen pressure of 6000 bar at 900 K. X‐ray investigations on powdered samples and elastic neutron diffraction experiments led to the atomic arrangement (space group: P4₂/mnm), which is characterized by isolated [RuD₇]‐anions. The coordination polyhedron formed by the seven deuterium ligands can be described as a distorted pentagonal bipyramide.     

Synthesis and Electrochemistry of Alkylidynetrihydridotriruthenium Clusters with Apical π-Substituents

The clusters, (-H)₃Ru₃( ₃-CY)(CO)_9–n (PPh₃) _n [Y=–CH₂CHCH₂, n=0 (1); Y=–CH₂CHCH₂, n=3 (2); Y=–C₆H₄CH₃, n=0 (3); Y=–C₆H₄CH₃, n=3 (4)], have been synthesized in good yields and characterized by IR and NMR spectroscopy and by elemental analysis. The electrochemical properties of these clusters is also reported. These data indicate that the -system of the apical substituent does not interact significantly with the cluster and should be available for further chemistry.     

Pyrene-Terminated Tin Sulfide Clusters: Optical Properties and Deposition on a Metal Surface

Herein, we present the synthesis of two pyrene-functionalized clusters, [(R^pyrSn)₄S₆]⋅2 CH₂Cl₂ ( 4 ) and [(R^pyrSn)₄Sn₂S₁₀]⋅n CH₂Cl₂ (n=4, 5 a ; n=2, 5 b ; R^pyr=CMe₂CH₂C(Me)N-NC(H)C₁₆H₉), both of which form in reactions of the organotin sulfide cluster [(R^NSn)₄S₆] ( C ; R^N=CMe₂CH₂C(Me)N-NH₂) with the well-known fluorescent dye 1-pyrenecarboxaldehyde ( B ). In contrast, reactions using an organotin sulfide cluster with another core structure, [(R^NSn)₃S₄Cl] ( A ), leads to formation of small molecular fragments, [(R^pyrCl₂Sn)₂S] ( 1 ), (pyren-1-ylmethylene)hydrazine ( 2 ), and 1,2-bis(pyren-1-ylmethylene)hydrazine ( 3 ). Besides synthesis and structures of the new compounds, we report the influence of the inorganic core on the optical properties of the dye, which was analyzed exemplarily for compound 5 a via absorption and fluorescence spectroscopy. This cluster was also used for exploring the potential of such non-volatile clusters for deposition on a metal surface under vacuum conditions.     

New route to 1,1-difluoro-5-methylquasisilatrane

A new route to 1,1-difluoro-5-methylquasisilatrane (N→Si) F₂Si(OCH₂CH₂)₂NMe is elaborated: the reaction of chlorinated methyltrifluorosilanes F₃SiCH_3−n Cln (n = 1–3) as well as trifluoro(3-chloropropyl) silane and trifluoro(propenyl)silane with N-methyl-bis(2-hydroxyethyl)amine. The reactivity of the silanes F₃SiCH_3−n Cl _n increases with the number of chlorine atoms, that is, with the electronegativity of the CH_3−n Cl _n group.     

Synthesis,characterization and reactions of the transition metal halogenoalkyl carbocation complexes [Cp(CO)2M{η2-CH2CH(CH2)nX}]PF6 (n = 1–8, 10, M = Fe; n = 3, 4 M = Ru; X = Br,I)

The halogenoalkyl complexes [Cp(CO)₂M{(CH₂)_nX}] (n = 3–10, 12, M = Fe; n = 5, 6, M = Ru, X = Br, I) react with Ph₃CPF₆ in dry CH₂Cl₂ to give the corresponding carbocation complexes [Cp(CO)₂M{η²-(CH₂CH(CH₂)_n?2X}]PF₆ in high yields. NMR evidence indicates that the metals form metallacyclopropane type structures with the carbocation ligand. The reactions of some of the cationic complexes with NaI, PPh₃, Na[Cp(CO)₂Fe] and Et₃N are discussed. NaI and Na[Cp(CO)₂Fe] displace the halogeno-olefin, while PPh₃ adds at the β-CH^δ+ giving the unstable phosphonium adducts [Cp(CO)₂Fe{CH₂CH(PPh₃)(CH₂)_n?2X}]PF₆ which decompose to the halogeno-olefins and the cationic PPh₃ complex [Cp(CO)₂Fe(PPh₃)]⁺. Et₃N causes allylic deprotonation forming internal olefin complexes of the type [Cp(CO)₂Fe{CH₂CHCH(CH₂)_n?3X}]PF₆.     

New sol–gel precursors for binary oxides of antimony,Sb<Subscript>2</Subscript>O<Subscript>3</Subscript> (senarmonite) and α-Sb<Subscript>2</Subscript>O<Subscript>4</Subscript>: synthesis and characterization of some ketoximate modified antimony(III) alkoxides

Hydrolysis of pure Sb(OPrⁱ)₃ by sol–gel method followed by sintering at 500 °C yields microcrystallites of Sb₂O₃ (senarmonite phase). Under similar conditions bimetallic alkoxide, [NaSb(OPrⁱ)₄], yields a mixture of binary oxides Sb₂O₃ and Sb₂O₄. Chemical modification of Sb(OPrⁱ)₃ with oximes forms monomeric products of the type [Sb(OPrⁱ)_3−n {ON=C(CH₃)R} _n ] {where R = CH₃, n = 1 [1]; n = 2 [2]; n = 3 [3]; R = 2-C₅H₄N, n = 1 [4]; n = 2 [5]; n = 3 [6]; R = 2-C₄H₃O, n = 1 [7]; n = 2 [8]; n = 3 [9]; R = 2-C₄H₃S, n = 1 [10]; n = 2 [11]; n = 3 [12]}. The liquid products [1–3, 7 & 10] were purified by distillation while the solids by recrystallization. All these products were characterized by elemental analyses, IR, NMR (¹H and ¹³C{¹H}) and representative derivatives [1], [2] and [3] by FAB mass studies. On the basis of these studies, a distorted pyramidal structure for all the derivatives may be assumed in the solution state containing an end-on coordination of oximes with the metal atom. Hydrolysis of the distilled precursors [1], [2] and [3] under sol–gel conditions yields pure nano-sized α-Sb₂O₄. All the oxides were characterized by XRD, SEM and EDX analysis exhibiting minimum particle size for the oxide obtained from the precursor [3].     

Optical properties of a tetradentate bis(beta-diketonate) europium(III) complex

Eu₂(BPOPB)₃H₂O, an europium complex chelated with bis(β-diketone), was synthesized. Its properties have been investigated by absorption spectrum, emission spectrum and luminescence lifetime measurement. The complex displays strong red luminescence upon irradiation at the ligand band around 355 nm, which indicates that the bis-β-diketonate ligand BPOPB is an efficient sensitizer. The Judd–Ofelt parameters obtained from the emission spectrum of Eu₂(BPOPB)₃H₂O have been used to calculate the total spontaneous emission probabilities (A), the radiative lifetime (τ_rad), the fluorescence branching ratio (β) and the stimulated emission cross-sections (σ). The luminescence lifetimes are determined to be 402 and 169 μs for Eu₂(BPOPB)₃H₂O and Eu(DBM)₃(H₂O)₂, respectively. The relationship between the structures of rare-earth complexes and luminescence lifetimes was analyzed. The radiative properties reveal that Eu₂(BPOPB)₃H₂O is potential to be an efficient luminescent material.     

The Heavy-Atom Effect on the Photophysics of Aromatic Hydrocarbons in the Presence of Solid Clays

The exchange of the original cation present on a Laponite clay (usually Na⁺) for heavy atoms such as Rb⁺, Cs⁺, and Tl⁺ significantly alters the emission characteristics of some aromatic hydrocarbons (p-terphenyl, naphthalene, pyrene, and biphenyl). The increase of the atomic mass of the cation induces a decrease of the fluorescence emission simultaneous with an increase of the emission in the region of lower energies of the spectra, ascribed to the phosphorescence of those hydrocarbons. Time-resolved experiments for the pyrene–clay system showed a decrease of singlet lifetimes for the heavier atoms. Hydrocarbon aggregates were also detected from both the emission spectra and the time-resolved studies. The “excimer-like” emission showed longer lifetimes (10–25 ns) than the monomolecular hydrocarbons (1–3 ns), as already found for other similar systems. The amount of aggregates increased for the heavier cations due to the smaller surface available on the clay particles. Experiments increasing the amount of Tl⁺ in samples containing a constant concentration of naphthalene allowed evaluation of the distance between the heavy atoms and the probe on the clay surface. The Perrin model treatment was used and resulted in approximately R₀=9.2 Å.