Catalytic properties of binuclear rhodium(II) complexes in hydrogenation and isomerization of allylbenzene

Binuclear hexafluoroacetylacetonate complexes of Rh(II) with axial ligands (Py, H₂O) exhibit activity in hydrogenation and isomerization of allylbenzene, and the isomerization reaction also takes place in an atmosphere of Ar. The catalytic system [Rh₂(hfacac)₄(H₂O)₂]-Ph₃P is much more active than Rh(II) hexafluoroacetylacetonate complexes in transformation of allylbenzene. Treatment of the acetate complex [Rh₂(O₂CCH₂)₄] with sodium borohydride significantly increases its activity, probably due to the formation of [Rh₂(O₂CCH₃)₃]⁺ and [Rh₂(O₂CCH₂)₂]²⁺ complexes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1957–1961, September, 1989.     

Rhodium (II) compounds with functionalized metalated phosphines as bridging ligands

The reaction of Rh₂(O₂CCH₃)₄ · 2CH₃OH with the phosphine P(4-BrC₆H₄)₂(C₆H₅), 2, results in the formation of the monometalated compound Rh₂(O₂CCH₃)₃[PC] · 2CH₃CO₂H (PC representing a metalated P(4-BrC₆H₄)₂(C₆H₅)). The reaction involves selective metalation of the phosphine at one Br-substituted ring (12:1 isomer ratio). The reaction of Rh₂(O₂CCH₃)₃[(4-BrC₆H₃)P(4-BrC₆H₄)(C₆H₅)] · 2CH₃CO₂H, 4, with one additional mol of triphenylphosphine yields a mixture of two main stereoisomers Rh₂(O₂CCH₃)₂[(4-BrC₆H₃)P(4-BrC₆H₄)(C₆H₅)] [(C₆H₄)P(C₆H₅)₂] · 2CH₃CO₂H, 5a and 5b, that were isolated as pure compounds. These two compounds were resolved in the corresponding M and P enantiomers as trifluoroacetate derivatives that show good enantioselectivities in catalytic transformation of α-diazocarbonyl compounds.     

Fast orthometalation reactions at a binuclear dirhodium(II) complex. Synthesis,crystal structure and reactivity of Rh2(O2CCH3)3[(C6H4)PPh2]·(HO2CCH3)2

From the reaction of Rh₂(O₂CCH₃)₄(MeOH)₂, in hot acetic acid with PPh₃ the monometalated intermediate Rh₂(O₂CCH₃)₃[(C₆H₄)PPh₂](HO₂CCH₃)₂ has been isolated and characterized by an X-ray study. This compound rapidly reacts with an excess of PPh₃ in dichloromethane at room temperature to give Rh₂(O₂CCH₃)₂-[(C₆H₄)PPh₂]₂(PPh₃)₂ with a head-to-tail structure. The same procedure at higher temperatures gives a mixture of this compound and another doubly metalated compound with a head-to-head structure.     

Synthesis,Structure, and Luminescence Properties of a {Mo6I8} Complex with (C6F5)2PO2 Ligands

Reaction of [Mo₆I₈(CH₃COO)₆]^2– with bis(pentafluorophenyl)phosphinic acid HO(O)P(C₆F₅)₂ yielded a new bright‐red luminescent complex [{Mo₆I₈}(O₂P(C₆F₅)₂)₆]^2–, isolated as (Bu₄N)(H₅O₂)[{Mo₆I₈}(O₂P(C₆F₅)₂)₆] · 3(Et₂O) · 1.5(acetone). It was characterized by X‐ray analysis, CV, ESI‐mass spectrometry, and NMR spectroscopy.     

Tris‐Functionalized Hybrid Anderson Polyoxometalates: Synthesis,Characterization, Hydrolytic Stability and Inversion of Protein Surface Charge

Single‐ and double‐sided functionalized hybrid organic–inorganic Anderson polyoxomolybdates with Ga^III and Fe^III positioned as central heteroatoms have been synthesized in a mild, two‐step synthesis in an aqueous medium. Compounds 1 – 4 were isolated as hydrated salts, [TBA]₃[GaMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]×12 H₂O ( 1 ) (TBA=tetrabutylammonium), Na₃[FeMo₆O₁₈{(OCH₂)₃CCH₂OH}₂]×11 H₂O ( 2 ), [TMA]₂[GaMo₆O₁₈(OH)₃{(OCH₂)₃CNH₃}]×7 H₂O ( 3 ) (TMA=tetramethylammonium), and Na[TMA]₂[FeMo₆O₁₈(OH)₃{(OCH₂)₃CNH₃}](OH)×6 H₂O ( 4 ). All the compounds were characterized based on single‐crystal X‐ray diffraction (SXRD), FTIR, UV/Vis, thermogravimetric, ESI‐MS, NMR, and elemental analyses. Compound 1 was also crystallized with two smaller organic cations, giving [TMA]₃[GaMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]×n H₂O ( 5 ) and [GDM]₃[GaMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]×n H₂O ( 6 ) (GDM=guanidinium) and were characterized based on UV/Vis, NMR, FTIR, and elemental analyses. The use of these compounds as additives in macromolecular crystallography was investigated by examining their hydrolytic stability by using ESI‐MS in a pH range of 4 to 9. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) analysis showed that BSA remains intact in a solution containing up to 100 equivalents of 1 or 4 over more than four days at 20 °C. Zeta potential measurements demonstrate that 1 – 4 induce charge inversions on the positively charged surface of BSA (1 mg mL^?1) with concentrations starting as low as 1.29 mM for compounds 1 and 2 , which have the highest negative surface charge.     

Synthesis,characterization and molecular docking of new C,N‐palladacycles containing pyridinium‐derived ligands: DNA and BSA interaction studies and evaluation as anti‐tumor agents

Four new monomeric Pd (II) complexes with formulas [Pd(C,N)‐(2′‐NH₂C₆H₄)C₆H₄ (N₃)(L)] ( A ), ( B ) and [Pd(C,N)‐C₆H₄CH₂NH(C₄H₉)(N₃)(L)] ( C ), ( D ), [L = isonicotinamide for ( A ) and ( C ), L = 4‐N,N‐dimethylaminopyridine for ( B ) and ( D )] have been synthesized using four initial dimers [Pd₂{(C,N)‐(2′‐NH₂C₆H₄)C₆H₄}₂(μ‐OAc)₂] ( 1 ), [Pd₂{(C,N)‐ (2′‐NH₂C₆H₄)C₆H₄}₂(μ‐N₃)₂] ( 3 ) for A and C , and [Pd₂{(C,N)‐C₆H₄CH₂NH(C₄H₉)}₂(μ‐OAc)₂] ( 2 ) and [Pd₂{(C,N)‐C₆H₄CH₂NH(C₄H₉)}₂(μ‐N₃)₂] ( 4 ) for B and D . Then synthesized complexes have been characterized by Fourier transform‐infrared, NMR spectroscopy and thermal gravimetric‐differential thermal analysis. Furthermore, UV–Vis spectroscopy, fluorescence spectroscopy, circular dichroism (CD) and helix melting temperature measurements have been employed to study the binding interaction of them with calf thymus‐deoxyribonucleic acid (DNA). The results reveal that all synthesized complexes can interact with DNA via groove‐binding mode. Bovine serum albumin (BSA)‐binding studies have been carried out using UV–Vis spectroscopy, emission titration and CD. However, competitive binding studies using warfarin, ibuprofen and digoxin on site markers demonstrated that the complexes bind to different sites on BSA. The results also indicated that the binding site was mainly located within site‐III for complex A , and site‐I for complexes B , C and D of BSA. In addition, molecular docking studies have been executed to determine the binding site of the DNA and BSA with complexes. Eventually, in vitro cytotoxicity of synthesized palladium complexes and cisplatin were carried out against human promyelocytic leukemia cancer (Hela) and breast cancer (MCF‐7) cell lines. Pursuant to the IC₅₀ values, the cytotoxicity of complexes against MCF‐7 was more than Hela.     

Synthesis,characterization and biological studies of alkenyl‐substituted titanocene(IV) carboxylate complexes

The carboxylate compounds [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})(O₂CCH₂SXyl)₂] (2; Xyl = 3,5‐Me₂C₆H₃) and [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})(O₂CCH₂SMesl)₂] (3; Mes 1 = 2,4,6‐Me₃C₆H₂) were synthesized by the reaction of [Ti(η⁵‐C₅H₅)(η⁵‐C₅H₄{CMe₂(CH₂CH₂CH?CH₂)})Cl₂] (1) with 2 equivalents of xylylthioacetic acid or mesitylthioacetic acid, respectively. Compounds 2 and 3 were characterized by spectroscopic methods. The cytotoxic activity of 1–3 was tested against human tumor cell lines from four different histogenic origins—8505C (anaplastic thyroid cancer), DLD‐1 (colon cancer) and the cisplatin sensitive A253 (head and neck cancer) and A549 (lung carcinoma)—and compared with those of the reference complex [Ti(η⁵‐C₅H₅)₂Cl₂] (R1) and cisplatin. Surprisingly, the cytotoxic activities of the carboxylate derivatives were lower than those of their corresponding dichloride analogue (1). However, complexes 1–3 were more active than titanocene dichloride against all the studied cells with the exception of complex 2 against A253 and A549 cell lines. DNA‐interaction tests were also carried out. Solutions of all the studied complexes were treated with different concentrations of fish sperm DNA, observing modifications of the UV spectra with intrinsic binding constants of 2.99 × 10⁵, 2.45 × 10⁵, and 2.35 × 10⁵ M ^?1 for 1–3. Structural studies based on density functional theory calculations of 2 and 3 were also carried out. Copyright © 2010 John Wiley & Sons, Ltd.     

Nucleophilic addition of water to coordinated dipyridylethylene in rhenium(V) complexes

Complexes of general formula [ReOX₂{(C₅H₄N)CH(O)CH₂(C₅H₄N)}] (X?=?Cl,?I) were prepared by reaction of trans-[ReOCl₃(PPh₃)₂] and trans-[ReOI₂(OEt)(PPh₃)₂] with cis-1,2-di-(2-pyridyl)ethylene (DPE) in ethanol and benzene in air. The coordinated DPE ligand undergoes addition of water at the ethylenic carbon atoms, and the (C₅H₄N)CH(O)CH₂(C₅H₄N) moiety acts as a uninegative terdentate N,O,N-donor ligand. X-ray crystal structures of both complexes have been determined and show distorted octahedral geometry at the rhenium(V) centre.     

Alkylation of [Pt2(μ-S)2(PPh3)4] with boronic acid derivatives

The reactivity of the metalloligand [Pt₂(μ-S)₂(PPh₃)₄] with the boron-functionalized alkylating agents BrCH₂(C₆H₄)B(OR)₂ (R = H or C(CH₃)₂) was investigated by electrospray ionization mass spectrometry (ESI-MS) in real time using pressurized sample infusion (PSI). The macroscopic reaction of [Pt₂(μ-S)₂(PPh₃)₄] with one mole equivalent of alkylating agents BrCH₂(C₆H₄)B{OC(CH₃)₂}₂ and BrCH₂(C₆H₄)B(OH)₂ gave the dinuclear monocationic μ-sulfide thiolate complexes [Pt₂(μ-S){μ-SCH₂(C₆H₄)B{OC(CH₃)₂}₂}(PPh₃)₄]⁺ and [Pt₂(μ-S){μ-S⁺CH₂(C₆H₄)B(OH)(O^?)}(PPh₃)₄]. The products were isolated as the [PF₆]^? salt and zwitterion, respectively, and fully characterized by ESI-MS, IR, ¹H and ³¹P NMR spectroscopy, and single-crystal X-ray structure determinations.     

Bis(dimethyl sulfoxide‐S)tetrakis(μ‐p‐hydroxybenzoato‐O:O′)dirhodium(II)–tetrakis(μ‐butyrato‐O:O′)bis(dimethyl sulfoxide‐S)dirhodium(II) cocrystal ethanol disolvate

The title structure, [Rh₂(C₇H₅O₃)₄(C₂H₆OS)₂]·[Rh₂(C₄H₇­O₂)₄(C₂H₆OS)₂]·2C₂H₆O, contains two discrete neutral Rh–Rh dimers cocrystallized as the ethanol disolvate. Each dimer is situated on an inversion center. The butyrate chain displays disorder in one C‐atom position. In each dimer, the di­methyl sulfoxide ligand (dmso) is bound via S, as expected. The ethanol is a hydrogen‐bond acceptor for one p‐hydroxy­benzoate hydroxyl group and acts as a hydrogen‐bond donor to the dmso O atom of a neighboring p‐hydroxy­benzoate dirhodium complex. A third hydrogen bond is formed from the other p‐hydroxy­benzoate hydroxyl group to the dmso O atom of a butyrate–dirhodium complex.     

Isomorphous rare‐earth tris[bis(2,6‐diisopropylphenyl) phosphate] complexes and their catalytic properties in 1,3‐diene polymerization and in the inhibited oxidation of polydimethylsiloxane

Crystals of mononuclear tris[bis(2,6‐diisopropylphenyl) phosphato‐κO]pentakis(methanol‐κO)lanthanide methanol monosolvates of lanthanum, [La(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 1 ), cerium, [Ce(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 2 ), and neodymium, [Nd(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 3 ), have been obtained by reactions between LnCl₃(H₂O)_n (n = 6 or 7) and lithium bis(2,6‐diisopropylphenyl) phosphate in a 1:3 molar ratio in methanol media. Compounds ( 1 )–( 3 ) crystallize in the monoclinic P2₁/c space group and have isomorphous crystal structures. All three bis(2,6‐diisopropylphenyl) phosphate ligands display a κO‐monodentate coordination mode. The coordination number of the metal atom is 8. Each [Ln{O₂P(O‐2,6‐ⁱPr₂C₆H₃)₂}₃(CH₃OH)₅] molecular unit exhibits four intramolecular O—H…O hydrogen bonds, forming six‐membered rings. The unit forms two intermolecular O—H…O hydrogen bonds with one noncoordinating methanol molecule. All six hydroxy H atoms are involved in hydrogen bonding within the [Ln{O₂P(O‐2,6‐ⁱPr₂C₆H₃)₂}₃(CH₃OH)₅]·CH₃OH unit. This, along with the high steric hindrance induced by the three bulky diaryl phosphate ligands, prevents the formation of a hydrogen‐bond network. Complexes ( 1 )–( 3 ) exhibit disorder of two of the isopropyl groups of the phosphate ligands. The cerium compound ( 2 ) demonstrates an essential catalytic inhibition in the thermal decomposition of polydimethylsiloxane in air at 573 K. Catalytic systems based on the neodymium complex tris[bis(2,6‐diisopropylphenyl) phosphato‐κO]neodymium, ( 3′ ), which was obtained as a dry powder of ( 3 ) upon removal of methanol, display a high catalytic activity in isoprene and butadiene polymerization.     

Paddlewheel dirhodium complexes bridged by para‐substituted benzoates

The dirhodium complex bis­(benzonitrile)tetra­kis[μ‐4‐(diethyl­amino)benzoato‐κ²O:O′]dirhodium(II)(Rh—Rh) benzonitrile disolvate, [Rh₂(C₁₁H₁₄NO₂)₄(C₇H₅N)₂]·2C₇H₅N, lies about an inversion centre. The dirhodium complex (methanol)tetra­kis(μ‐4‐nitro­benzoato‐κ²O:O′)(pyridine)dirhodium(II)(Rh—Rh) dichloro­methane solvate, [Rh₂(C₇H₄NO₄)₄(C₅H₅N)(CH₄O)]·CH₂Cl₂, lies in a general position in the unit cell, but the complexes dimerize around an inversion centre via O—H⋯O hydrogen bonding of the axial MeOH to a carboxyl­ate O atom. In the latter crystal structure, π–π stacking inter­actions between the bridging 4‐nitro­benzoate ligands and the axial pyridine ligand are observed between adjacent mol­ecules.     

Heterometallic Polyhydride Complexes Containing Yttrium Hydrides with Different Cp Ligands: Synthesis,Structure, and Hydrogen‐Uptake/Release Properties

A new family of Y₄/M₂ and Y₅/M heterobimetallic rare‐earth‐metal/d‐block‐transition‐metal? polyhydride complexes has been synthesized. The reactions of the tetranuclear yttrium? octahydride complex [{Cp′′Y(μ‐H)₂}₄(thf)₄] (Cp′′=C₅Me₄H, 1‐C₅Me₄H ) with one equivalent of Group‐6‐metal? pentahydride complexes [Cp*M(PMe₃)H₅] (M=Mo, W; Cp*=C₅Me₅) afforded pentanuclear heterobimetallic Y₄/M? polyhydride complexes [{(Cp′′Y)₄(μ‐H)₇}(μ‐H)₄MCp*(PMe₃)] (M=Mo ( 2 a ), W ( 2 b )). UV irradiation of compounds 2 a , b in THF gave PMe₃‐free complexes [{(Cp′′Y)₄(μ‐H)₆(thf)₂}(μ‐H)₅MCp*] (M=Mo ( 3 a ), W ( 3 b )). Compounds 3 a , b reacted with one equivalent of [Cp*M(PMe₃)H₅] to afford hexanuclear Y₄/M₂ complexes [{Cp*M(μ‐H)₅}{(Cp′′Y)₄(μ‐H)₅}{(μ‐H)₄MCp*(PMe₃)}] (M=Mo ( 4 a ), W ( 4 b )). UV irradiation of compounds 4 a , b provided the PMe₃‐free complexes [(Cp′′Y)₄(μ‐H)₄{(μ‐H)₅MCp*}₂] (M=Mo ( 5 a ), W ( 5 b )). C₅Me₄Et‐ligated analogue [(Cp′′Y)₄(μ‐H)₄{(μ‐H)₅Mo(C₅Me₄Et)}₂] ( 5 a′ ) was obtained from the reaction of 1‐C₅Me₄H with [(C₅Me₄Et)Mo(PMe₃)H₅]. On the other hand, the reaction of pentanuclear yttrium? decahydride complex [{(C₅Me₄R)Y(μ‐H)₂}₅(thf)₂] ( 1‐C₅Me₅ : R=Me; 1‐C₅Me₄Et : R=Et) with [Cp*M(PMe₃)H₅] gave the hexanuclear heterobimetallic Y₅/M? polyhydride complexes [({(C₅Me₄R)Y}₅(μ‐H)₈)(μ‐H)₅MCp*] ( 6 a : M=Mo, R=Me; 6 a′ : M=Mo, R=Et; 6 b : M=W, R=Me). Compound 5 a released two molecules of H₂ under vacuum to give [(Cp′′Y)₄(μ‐H)₂{(μ‐H)₄MoCp*}₂] ( 7 ). In contrast, compound 6 a lost one molecule of H₂ under vacuum to yield [{(Cp*Y)₅(μ‐H)₇}(μ‐H)₄MoCp*] ( 8 ). Both compounds 7 and 8 readily reacted with H₂ to regenerate compounds 5 a and 6 a , respectively. The structures of compounds 4 a , 5 a′ , 6 a′ , 7 , and 8 were determined by single‐crystal X‐ray diffraction.     

Regioselective ortho‐Metallation of 2‐Diphenylphosphanylpyridine and (2‐(2‐Diphenylphosphanyl)phenyl)‐1‐3‐dioxalane with Methyltetrakis(trimethylphosphane)cobalt(I)

Co(CH₃)(PMe₃)₄ forms 100 % regioselectively with (2‐(2‐diphenylphosphanyl)phenyl)‐1,3‐dioxalane and 2‐diphenylphosphanyl‐pyridine, by elimination of methane, the four‐membered metallacycles Co{(C₃O₂HC₆H₃)P(C₆H₅)₂}(PMe₃)₃ ( 1 ) and Co{(CNC₄H₃)P(C₆H₅)₂}(PMe₃)₃ ( 4 ). The regioselectivity is independent of the steric requirement of the ortho substituent in the 2‐diphenylphosphanylaryl‐ligands. Oxidative addition with iodomethane transforms 1 and 4 into octahedral, diamagnetic low‐spin d⁶ complexes Co(CH₃)I‐{(C₃O₂HC₆H₃)P(C₆H₅)₂}(PMe₃)₂ ( 2 ) and Co(CH₃)I‐{(CNC₄H₃)P(C₆H₅)₂}(PMe₃)₂ ( 5 ). Under an atmosphere of carbon monoxide, insertion into the Co‐C bond results in ring expansion by forming the new assembled phosphanylbenzoyl complexes Co{(C₄O₃HC₆H₃)‐P(C₆H₅)₂}CO(PMe₃)₂ ( 3 ) and Co{(OCNC₄H₃)P(C₆H₅)₂}CO(PMe₃)₂ ( 6 ). The three different types of cobaltacycles are supported by X‐ray diffraction of 1 , 3 , 5 and 6 .     

catena‐Poly[[[tetrakis(μ‐acetato‐κ2O:O′)dirhodium(II)]‐μ‐[1,3‐bis(dimethylamino)propan‐2‐ol‐κ2N:N′]] tetrahydrofuran hemisolvate]

In the structure of the title compound, {[Rh₂(C₂H₃O₂)₄(C₇H₁₈N₂O)]·0.5C₄H₈O}_n or {[Rh₂(O₂CMe)₄(Hbdmap)]·0.5C₄H₈O}_n, where Hbdmap is 1,3‐bis­(dimethyl­amino)propan‐2‐ol, each Hbdmap ligand is coordinated to two [Rh₂(O₂CMe)₄] units by two N atoms, resulting in a polymeric chain structure. The observed coordination mode of the Hbdmap mol­ecule is unprecedented.     

Influence of Cyclopentadienyl Ring‐Tilt on Electron‐Transfer Reactions: Redox‐Induced Reactivity of Strained [2] and [3]Ruthenocenophanes

In contrast to ruthenocene [Ru(η⁵‐C₅H₅)₂] and dimethylruthenocene [Ru(η⁵‐C₅H₄Me)₂] ( 7 ), chemical oxidation of highly strained, ring‐tilted [2]ruthenocenophane [Ru(η⁵‐C₅H₄)₂(CH₂)₂] ( 5 ) and slightly strained [3]ruthenocenophane [Ru(η⁵‐C₅H₄)₂(CH₂)₃] ( 6 ) with cationic oxidants containing the non‐coordinating [B(C₆F₅)₄]^? anion was found to afford stable and isolable metal?metal bonded dicationic dimer salts [Ru(η⁵‐C₅H₄)₂(CH₂)₂]₂[B(C₆F₅)₄]₂ ( 8 ) and [Ru(η⁵‐C₅H₄)₂(CH₂)₃]₂[B(C₆F₅)₄]₂ ( 17 ), respectively. Cyclic voltammetry and DFT studies indicated that the oxidation potential, propensity for dimerization, and strength of the resulting Ru?Ru bond is strongly dependent on the degree of tilt present in 5 and 6 and thereby degree of exposure of the Ru center. Cleavage of the Ru?Ru bond in 8 was achieved through reaction with the radical source [(CH₃)₂NC(S)S?SC(S)N(CH₃)₂] (thiram), affording unusual dimer [(CH₃)₂NCS₂Ru(η⁵‐C₅H₄)(η³‐C₅H₄)C₂H₄]₂[B(C₆F₅)₄]₂ ( 9 ) through a haptotropic η⁵–η³ ring‐slippage followed by an apparent [2+2] cyclodimerization of the cyclopentadienyl ligand. Analogs of possible intermediates in the reaction pathway [C₆H₅ERu(η⁵‐C₅H₄)₂C₂H₄][B(C₆F₅)₄] [E=S ( 15 ) or Se ( 16 )] were synthesized through reaction of 8 with C₆H₅E?EC₆H₅ (E=S or Se).     

Über Reaktionen des P4S10 mit siliciumorganischen Verbindungen

Reactions of P₄S₁₀ with Organosilicon Compounds P₄S₁₀ ( 1 ) can be degraded with silicon-nitrogen compounds. 1 reacts with (CH₃)₃Si? N(CH₃)₂ ( 2 a ) and (CH₃)₃Si? N(C₂H₅)₂ ( 2 b ) to yield S?P[N(CH₃)₂]₂SSi(CH₃)₃ ( 3 a ) and ( 3 b ). By the reaction of 1 with [(CH₃)₃Si]₂S ( 4 ) S?P[S? Si(CH₃)₃]₃ ( 6 ) is formed in high yield. (C₆H₅PS₂)₂ ( 7 ) was used as a model to investigate the course of the reaction. This leads to C₆H₅P(S)? [N(CH₃)₂]SSi(CH₃)₃ ( 9 ) and C₆H₅P(S)[SSi(CH₃)₃]₂ ( 10 ). The reaction mechanism will be discussed. The n.m.r. data and mass spectra are reported.     

Synthesis and coordination chemistry of fluorinated phosphonic acids

Phosphonic acids [(HO)₂P(O)C₂H₄C_nF_2n+1] (n = 4, 6) and [(HO)₂P(O)C₆H₄-4-C_nF_2n+1] (n = 0, 1, 6) have been prepared in good yields. Deprotonation and reaction with cis-[PtCl₂(PPh₃)₂] affords fluorinated platinum complexes which have been characterised by elemental analysis, mass spectrometry, IR and NMR spectroscopies. The structures of [Pt{O₂P(O)C₆H₄-4-F}(PPh₃)₂], [Pt{O₂P(O)C₆H₄-4-CF₃}(PPh₃)₂] and [Pt{O₂P(O)C₂H₄C₆F₁₃}(PPh₃)₂] have been determined by single crystal X-ray diffraction.     

Phosphaniminato‐Acetato‐Cluster von Kupfer und Zink. Kristallstrukturen von [Cu4(NPEt3)2(O2CCH3)6] und [Zn4(NPEt3)2(O2CCH3)6]

Phosphoraneiminato Acetate Cluster of Copper and Zinc. Crystal Structures of [Cu₄(NPEt₃)₂(O₂CCH₃)₆] and [Zn₄(NPEt₃)₂(O₂CCH₃)₆] The anhydrous acetates of copper(II) and zinc react with the silylated phosphaneimine Me₃SiNPEt₃ in dichloromethane at 20 °C forming the mixed phosphoraneiminato acetate clusters [Cu₄(NPEt₃)₂(O₂CCH₃)₆] ( 1 ), which forms emerald crystals, and colourless [Zn₄(NPEt₃)₂ · (O₂CCH₃)₆] ( 2 ). In spite of analogous composition the structures of 1 and 2 are completely different. In the asymmetric unit of 1 three copper atoms of an almost isosceles triangle are linked via two nitrogen atoms of the NPEt₃^– groups to form a trigonal bipyramidal aggregate. One of these three copper atoms is chelated by an acetate group, another one is connected with the fourth copper atom via three μ₂‐O₂C–CH₃ groups. The asymmetric units are associated via a μ₂‐O₂C–CH₃ group and a μ₃‐OC(O)CH₃ group at a time so that infinite chains result. In 2 two zinc atoms are linked via the nitrogen atoms of the two NPEt₃^– groups to form an almost centrosymmetric four‐membered ring. Both nitrogen atoms of the four‐membered ring are connected with another zinc atom each. These zinc atoms again are linked with the zinc atoms of the Zn₂N₂ four‐membered ring via two μ₂‐O₂C–CH₃ groups each and additionally coordinated with a terminal acetate ligand each.     

Role of hydrogen peroxide in the synthesis of nitrogen heterocycle containing cobalt complexes

The reactions of Co(O₂CCH₃)₂·4H₂O with the sodium salt of p-toluene sulfonic acid (NapTS) and pyridine (py) or 4-methylpyridine (4mepy) in the presence of hydrogen peroxide in methanol led to the formation of [Co(py)₃(H₂O)₃](pTS)₂ or [Co(4mepy)₂(H₂O)₄](pTS)₂·MeOH, respectively. The coordination polymer [{Co(44′bpy)(H₂O)₄}(pTS)₂]_n (4,4′-bipyridine = 44′bpy) was obtained from the reaction of Co(O₂CCH₃)₂·4H₂O with 44′bpy in the presence of NapTS. The reaction of Co(O₂CCH₃)₂·4H₂O, 2,2′-bipyridine (22′bpy) and NapTS with hydrogen peroxide resulted in the formation of the dinuclear complex [Co₂(μ-OH)₂(μ-O₂CCH₃)(O₂CCH₃)₂(22′bpy)₂](pTS). Characterization of these complexes and the role of hydrogen peroxide in these reactions are discussed. Similar reactions with sodium sulfamate gave the mononuclear [Co(22′bpy)₂(O₂CCH₃)]NH₂SO₃·2H₂O complex and [Co₂(μ-OH)₂(μ-O₂CCH₃)(O₂CCH₃)₂(22′bpy)₂](NH₂SO₃).