INORGANIC RINGS WITH GALLIUM ORGANYLS AND IMINODIPHOSPHINECHALCHOGENIDES

The organometallic complexes of general formula [Me ₂ Ga{(XPR ₂ ) (YPR′ ₂ )N}] (R, R′ = Ph, X, Y = O, (1); R, R′ = Ph, X, Y = S (2); R, R′ = Ph, X = O, Y = S (3); R = Me, R′ = Ph, X = O, Y = S (4)) were obtained by alkane eliminations from Me ₃ Ga and the free acidic ligands, LH, in toluene solutions. Complexes 1– 4 seem to be potential precursors to cationic gallium species.     

Organometallic Niobium and Tantalum Complexes with Primary Phosphine Ligands: Syntheses and Molecular Structures of [Cp*MCl4(PH2R)] (M = Nb,Ta; Cp* = C5Me5;R = But,Ad, Cy,Ph, 2, 4, 6‐Me3C6H2 (Mes))

The reaction of [Cp*MCl₄] (M = Nb, Ta; Cp* = C₅Me₅) with PH₂R in toluene at room temperature gives the primary phosphine complexes [Cp*MCl₄(PH₂R)] [Cp* = C₅Me₅; M = Nb: R = Bu^t ( 1a ), Ad ( 2a ), Cy ( 3a ), Ph ( 4a ), 2, 4, 6‐Me₃C₆H₂ (Mes) ( 5a ); M = Ta: R = Bu^t ( 1b ), Ad ( 2b ), Cy ( 3b ), Ph ( 4b ), Mes ( 5b )] in high yield. 1—5 were characterized spectroscopically (NMR, IR, MS) and by crystal structure determinations. The starting material [Cp*TaCl₄] is monomeric in the solid state, as shown by crystal structure determination.     

Sterically Demanding Novel Triazole Based Tertiary Phosphines: Synthesis,Transition Metal Chemistry and Catalytic Applications

Sterically demanding 2,6-dibenzhydryl-4-methylphenyl and 1,2,3-triazole based tertiary phosphines, [Ar*{1,2,3-N₃C(Ph)C(PR₂)}] (R=Ph, 3 ; R=ⁱPr, 4 ) were obtained by the temperature-controlled lithiation of 1-(2,6-dibenzydryl-4-methyl)-5-iodo-4-phenyl-1H-1,2,3-triazole ( 2 ) followed by the reaction with R₂PCl (R=Ph, ⁱPr). Treatment of 3 with H₂O₂, elemental sulfur and selenium yielded chalcogenides [Ar*{1,2,3-N₃C(Ph)C(P(E)Ph₂)}] (E=O, 5 ; E=S, 6 ; E=Se, 7 ). The reaction of 3 with [Pd(COD)Cl₂] in 1 : 1 molar ratio, afforded dimeric complex [Pd(μ₂-Cl)Cl{Ar*{1,2,3-N₃C(Ph)C(PPh₂)}-κ¹-P}]₂ ( 8 ), whereas the reactions of 3 and 4 with [Pd(η³-C₃H₅)Cl]₂ in 2 : 1 molar ratios produced complexes [Pd(η³-C₃H₅)Cl{Ar*{1,2,3-N₃C(Ph)C(PR₂)}-κ¹-P}] (R=Ph, 9 ; R=ⁱPr, 10 ). Treatment of 3 with [Pd(OAc)₂] in 1 : 1 molar ratio afforded a rare trinuclear complex [{Pd₃(OAc)₄}{Ar*{1,2,3-N₃C(C₆H₄)C(PPh₂)}-κ²-C,P}₂] ( 11 ). Treatment of 3 and 4 with [AuCl(SMe₂)] resulted in [AuCl{Ar*{1,2,3-N₃C(Ph)C(PR₂)}-κ¹-P}] (R=Ph, 12 ; R=ⁱPr, 13 ). Bulky phosphine 4 was very effective in Suzuki-Miyaura coupling and amination reactions with very low catalyst loading. Molecular structures of 3 – 5 , and 8 – 13 were confirmed by single-crystal X-ray diffraction studies.     

Übergangsmetall-Silyl-Komplexe, 44. Darstellung der zweikernigen Silyl-Komplexe (CO)3(R3Si)Fe(μ-PR′R′′)Pt(PPh3)2 durch oxidative Addition von (CO)3(R′R′′HP)Fe(H)SiR3 an (C2H4)Pt(PPh3)2

Transition Metal Silyl Complexes, 44. — Preparation of the Binuclear Silyl Complexes (CO)₃(R₃Si)Fe(μ-PR′R′′)Pt(PPh₃)₂ by Oxidative Addition of (CO)₃(R′R′′HP)Fe(H)SiR₃ to (C₂H₄)Pt(PPh₃)₂ The complexes (CO)₃(R′R′′HP)Fe(H)SiR₃ ( 1 ) [PHR′R′′ = PHPh₂, PH₂Ph, PH₂Cy; SiR₃ = SiPh₃, SiPh₂Me, SiPhMe₂, Si(OMe)₃] react with Pt(C₂H₄)(PPh₃)₂ to give the dinuclear, silyl-substituted complexes (CO)₃(R₃Si)Fe(μ-PR′R′′)Pt(PPh₃)₂ ( 2 ) in high yields. Upon reaction of 2 (R = R′ R′′ = Ph) with CO, the PPh₃ ligand at Pt being trans to the PPh₂ bridge is exchanged, and (CO)₃(Ph₃Si)Fe(μ-PPh₂)Pt(PPh₃)CO ( 3 ) is formed. Complex 3 is characterized by an X-ray structure analysis. The rather short Fe — Si distance [233.9(2) pm] and the infrared spectrum of 3 indicate that the Fe — Pt bond is quite polar.     

Selenoquinones Stabilized by Ruthenium(II) Arene Complexes: Synthesis,Structure, and Cytotoxicity

A new series of monoselenoquinone and diselenoquinone π complexes, [(η⁶‐p‐cymene)Ru(η⁴‐C₆R₄SeE)] (R=H, E=Se ( 6 ); R=CH₃, E=Se ( 7 ); R=H, E=O ( 8 )), as well as selenolate π complexes [(η⁶‐p‐cymene)Ru(η⁵‐C₆H₃R₂Se)][SbF₆] (R=H ( 9 ); R=CH₃ ( 10 )), stabilized by arene ruthenium moieties were prepared in good yields through nucleophilic substitution reactions from dichlorinated‐arene and hydroxymonochlorinated‐arene ruthenium complexes [(η⁶‐p‐cymene)Ru(C₆R₄XCl)][SbF₆]₂ (R=H, X=Cl ( 1 ); R=CH₃, X=Cl ( 2 ); R=H, X=OH ( 3 )) as well as the monochlorinated π complexes [(η⁶‐p‐cymene)Ru(η⁵‐C₆H₃R₂Cl)][SbF₆]₂ (R=H ( 4 ); R=CH₃ ( 5 )). The X‐ray crystallographic structures of two of the compounds, [(η⁶‐p‐cymene)Ru(η⁴‐C₆Me₄Se₂)] ( 7 ) and [(η⁶‐p‐cymene)Ru(η⁴‐C₆H₄SeO)] ( 8 ), were determined. The structures confirm the identity of the target compounds and ascertain the coordination mode of these unprecedented ruthenium π complexes of selenoquinones. Furthermore, these new compounds display relevant cytotoxic properties towards human ovarian cancer cells.     

Transition metal chemistry of phosphorus based ligands. Ruthenium(II) chemistry of bis(phosphino)amines, X2PN(R)PX2 (R=H or Ph, X=Ph; R=Ph, X2=O2C6H4)

Reactions of CpRuCl(PPh₃)₂ with bis(phosphino)amines, X₂PN(R)PX₂ (1 R=H, X=Ph; 2 R=X=Ph; 3 R=Ph, X₂=O₂C₆H₄) give neutral or cationic mononuclear complexes depending on the reaction conditions. Reaction of 1 with CpRuCl(PPh₃)₂ gives one neutral complex, [CpRu(Cl)(η²-Ph₂PN(H)PPh₂)] (4) and two cationic complexes, [CpRu(η²-Ph₂PN(H)PPh₂)(η¹-Ph₂PN(H)PPh₂)]Cl (5) and [CpRu(PPh₃)(η²-Ph₂PN(H)PPh₂)]Cl (6), whereas the reaction of 2 with CpRuCl(PPh₃)₂ leads only to the isolation of cationic complex, [CpRu(PPh₃)(η²-Ph₂PN(Ph)PPh₂)]Cl (7). The catechol derivative 3, in a similar reaction, affords an interesting mononuclear complex [CpRu(PPh₃){η¹-(C₆H₄O₂)PN(Ph)P(O₂H₄C₆)}₂]Cl (8) containing two monodentate bis(phosphino)amine ligands. The structural elucidation of the complexes was carried out by elemental analyses, IR and NMR spectroscopic data.     

Syntheses and Structures of trans-bis(Alkenylacetylide) Ruthenium Complexes

A series of ruthenium alkenylacetylide complexes trans-[Ru{C≡CC(=CH₂)R}Cl(dppe)₂] (R=Ph ( 1 a ), ^cC₄H₃S ( 1 b ), 4-MeS-C₆H₄ ( 1 c ), 3,3-dimethyl-2,3-dihydrobenzo[b]thiophene (DMBT) ( 1 d )) or trans-[Ru{C≡C-^cC₆H₉}Cl(dppe)₂] ( 1 e ) were allowed to react with the corresponding propargylic alcohol HC≡CC(Me)R(OH) (R=Ph ( A ), ^cC₄H₃S ( B ), 4-MeS-C₆H₄ ( C ), DMBT ( D ) or HC≡C-^cC₆H₁₀(OH) ( E ) in the presence of TlBF₄ and DBU to presumably give alkenylacetylide/allenylidene intermediates trans-[Ru{C≡CC(=CH₂)R}{C=C=C(Me)}(dppe)₂]PF₆ ([ 2 ]PF₆). These complexes were not isolated but deprotonated to give the isolable bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH₂)R}₂(dppe)₂] (R=Ph ( 3 a ), ^cC₄H₃S ( 3 b ), 4-MeS-C₆H₄ ( 3 c ), DMBT ( 3 d )) and trans-[Ru{C≡C-^cC₆H₉}₂(dppe)₂] ( 3 e ). Analogous reactions of trans-[Ru(CH₃)₂(dmpe)₂], featuring the more electron-donating 1,2-bis(dimethylphosphino)ethane (dmpe) ancillary ligands, with the propargylic alcohols A or C and NH₄PF₆ in methanol allowed isolation of the intermediate mixed alkenylacetylide/allenylidene complexes trans-[Ru{C≡CC(=CH₂)R}{C=C=C(Me)}(dmpe)₂]PF₆ (R=Ph ([ 4 a ]PF₆), 4-MeS-C₆H₄ ([ 4 c ]PF₆). Deprotonation of [ 4 a ]PF₆ or [ 4 c ]PF₆ gave the symmetric bis(alkenylacetylide) complexes trans-[Ru{C≡CC(=CH₂)R}₂(dmpe)₂] (R=Ph ( 5 a ), 4-MeS-C₆H₄ ( 5 c )), the first of their kind containing the dmpe ancillary ligand sphere. Attempts to isolate bis(allenylidene) complexes [Ru{C=C=C(Me)R}₂(PP)₂]²⁺ (PP=dppe, dmpe) from treatment of the bis(alkenylacetylide) species 3 or 5 with HBF₄ ⋅ Et₂O were ultimately unsuccessful.     

Five-Membered Ruthenacycles: Ligand-Assisted Alkyne Insertion into 1,3-N,S-Chelated Ruthenium Borate Species

Building upon previous work, the chemistry of [(η⁶-p-cymene)Ru{P(OMe)₂OR}Cl₂], (R=H or Me) has been extended with [H₂B(mbz)₂]⁻ (mbz=2-mercaptobenzothiazolyl) using different Ru precursors and borate ligands. As a result, a series of 1,3-N,S-chelated ruthenium borate complexes, for example, [(κ²-N,S-L)PR₃Ru{κ³-H,S,S’−H₂B(L)₂}], ( 2 a – d and 2 a’ – d’ ; R=Ph, Cy, OMe or OPh and L=C₅H₄NS or C₇H₄NS₂) and [Ru{κ³-H,S,S’-H₂B(L)₂}₂], ( 3 : L=C₅H₄NS, 3’ : L=C₇H₄NS₂) were isolated upon treatment of [(η⁶-p-cymene)RuCl₂PR₃], 1 a – d (R=Ph, Cy, OMe or OPh) with [H₂B(mp)₂]⁻ or [H₂B(mbz)₂]⁻ ligands (mp=2-mercaptopyridyl). All the Ru borate complexes, 2 a – d and 2 a’ – d’ are stabilized by phosphine/phosphite and hemilabile N,S-chelating ligands. Treatment of these Ru borate species, 2 a’ – c’ with various terminal alkynes yielded two different types of five-membered ruthenacycle species, namely [PR₃{C₇H₄S₂-(E)-N-C=CH(R ’ )}Ru{κ³-H,S,S ’ −H₂B(L)₂}], ( 4 – 4’ ; R=Ph and R ’ =CO₂Me or C₆H₄NO₂; L=C₇H₄NS₂) and [PR₃{C₇H₄NS-(E)-S-C=CH(R ’ )}Ru{κ³-H,S,S ’ −H₂B(L)₂}], ( 5 – 5’ , 6 and 7 ; R=Ph, Cy or OMe and R ’ =CO₂Me or C₆H₄NO₂; L=C₇H₄NS₂). All these five-membered ruthenacycle species contain an exocyclic C=C moiety, presumably formed by the insertion of a terminal alkyne into the Ru−N and Ru−S bonds. The new species have been characterized spectroscopically and the structures were further confirmed by single-crystal X-ray diffraction analysis. Theoretical studies and chemical-bonding analyses established that charge transfer occurs from phosphorus to ruthenium center following the trend PCy₃<PPh₃<P(OPh)₃<P(OMe)₃.     

Monomere Tripod–Zink-Thiolat-Komplexe

Monomeric Tripod–Zinc Thiolate Complexes Reaction of the pyrazolylborate-zinc complex Tp^Cum,MeZn–OH with the corresponding thiols yielded the stable complexes Tp^Cum,MeZn–SR ( 1 : R = Ph, 2 : R = CH₂–Ph, 3 : R = CH₂–CH₂–Ph) which are further representatives of this class of compounds. Using the ligand tris(benzimidazolylmethyl)amine (BIMA), zinc perchlorate, and the corresponding sodium thiolates, the cationic complexes (BIMA)Zn–SR (R = Ph, CH₂Ph) were obtained, which were isolated as [(BIMA)Zn–S–Ph] BPh₄ ( 4 ) and [(BIMA)Zn–S–CH₂Ph] ClO₄ ( 5 ). A structure determination of 4 confirmed the pseudotetrahedral coordination geometry for this new type of compounds.     

Chemistry of Fischer-type rhenacyclobutadiene complexes. II. Reactions with alkynes and sulfonium ylides, and rearrangements induced by nitriles and pyridine

Further investigations into the chemistry of the rhenacyclobutadiene complexes (CO)₄Re(η²-C(R)C(CO₂Me)C(X)) (1: R=Me, X=OEt (1a), O(CH₂)₃CCH (1b), NEt₂ (1c); R=CHEt₂, X=OEt (1d); R=Ph, X=OEt (1e)) are reported. Reactions of 1 with alkynes at reflux temperature of toluene and at ambient temperature either under photochemical conditions or in the presence of PdO yield ring-substituted η⁵-cyclopentadienylrhenium tricarbonyl complexes, 2. The symmetrical alkynes R^′CCR^′ (R^′=Ph, Me, CO₂Me) afford the pentasubstituted complexes (η⁵-C₅(Me)(CO₂Me)(OEt)(Ph)(Ph))Re(CO)₃ (2d), (η⁵-C₅(Me)(CO₂Me)(OEt)(Me)(Me))Re(CO)₃ (2e), (η⁵-C₅(Me)(CO₂Me)(OEt)(CO₂Me)(CO₂Me))Re(CO)₃ (2f), and (η⁵-C₅(Me)(CO₂Me)(NEt₂)(CO₂Me)(CO₂Me))Re(CO)₃ (2i) on reaction with the appropriate 1, whereas the unsymmetrical alkynes R^′CCR″ (R^′=Ph; R″=H, Me) give either only one, (η⁵-C₅(Me)(CO₂Me)(OEt)(Ph)H)Re(CO)₃ (2a)), or both, (η⁵-C₅(Me)(CO₂Me) (OEt)(Ph)(Me))Re(CO)₃ (2b) and (η⁵-C₅(Me)(CO₂Me)(OEt)(Me)(Ph))Re(CO)₃ (2c), (η⁵-C₅(Ph)(CO₂Me)(OEt)(Ph)H)Re(CO)₃ (2g) and (η⁵-C₅(Ph)(CO₂Me)(OEt)(H)(Ph))Re(CO)₃ (2h), of the possible products of [3 + 2] cycloaddition of alkyne to η²-C(R)C(CO₂Me)C(X). Thermolysis of (CO)₄Re(η²-C(Me)C(CO₂Me)C(O(CH₂)₃CCH)) (1b) containing a pendant alkynyl group proceeds to (η⁵-C₅(Me)(CO₂Me)(O(CH₂)₃)H)Re(CO)₃ (2j), a η⁵-cyclopentadienyl-dihydropyran fused-ring product. Competition experiments showed that each of PhCCH and MeO₂CCCCO₂Me reacts faster than PhCCPh with 1a. The results with unsymmetrical alkynes are rationalized by steric properties of substituents at the CC and ReC bonds and by a preference of ReC(Me) over ReC(OEt) to undergo alkyne insertion. A mechanism is proposed that involves substitution of a trans CO by alkyne in 1, insertion of alkyne into ReC bond to give a rhenabenzene intermediate, and collapse of the latter to 2. Complexes 1a and 1d undergo rearrangement in MeCN at reflux temperature to give rhenafuran-like products, (CO)₄Re(κ²-OC(OMe)C(CHCR₂)C(OEt)) (R=H (3a) or Et (3b)). The reaction of 1d also proceeds in EtCN, PhCN, and t-BuCN at comparable temperature, but is slower (especially in t-BuCN) than in MeCN. In pyridine at reflux temperature, 1a undergoes a similar rearrangement, with CO substitution, to give (CO)₃(py)Re(κ²-OC(OMe)C(CHCEt₂)C(OEt)) (4). A mechanism is proposed for these reactions. The sulfonium ylides Me₂SCHC(O)Ph and Me₂SC(CN)₂ (Me₂SCRR^′) react with 1a in acetonitrile at reflux temperature by nucleophilic addition of the ylide to the ReC(Me) carbon, loss of Me₂S, and rearrangement to a rhenafuran-type structure to yield (CO)₄Re(κ²-OC(OMe)C(C(Me)CRR^′)C(OEt)) (R=H, R^′=C(O)Ph (5a); R=R^′CN (5b)). All new compounds were characterized by a combination of elemental analysis, mass spectrometry, and IR and NMR spectroscopy.     

1‐Azaallyl Complexes of NiII,PdII, and TiIII

The metal complexes [Ni{N(Ar)C(R)C(H)Ph}₂) ( 2 ) (Ar = 2,6‐Me₂C₆H₃, R = SiMe₃), [Ti(Cp₂){N(R)C(Bu^t)C(H)R}] ( 3 ), M{N(R)C(Bu^t)C(H)R}I [M = Ni ( 4 a ) or Pd ( 4 b )] and [M{N(R)C(Bu^t)C(H)R}I(PPh₃)] [M = Ni ( 5 a ) or Pd ( 5 b )] have been prepared from a suitable metal halide and lithium precursor of ( 2 ) or ( 3 ) or, alternatively from [M(LL)₂] (M = Ni, LL = cod; M = Pd, LL = dba) and the ketimine RN = C(Bu^t)CH(I)R ( 1 ). All compounds, except 4 were fully characterised, including the provision of X‐ray crystallographic data for complex 5 a .     

Unerwartete Reduktion von [Cp*TaCl4(PH2R)] (R = But,Cy, Ad,Ph, 2,4,6‐Me3C6H2; Cp* = C5Me5) durch Reaktion mit DBU – Molekülstruktur von [(DBU)H][Cp*TaCl4] (DBU = 1,8‐Diazabicyclo[5.4.0]undec‐7‐en)

Unexpected Reduction of [Cp*TaCl₄(PH₂R)] (R = Bu^t, Cy, Ad, Ph, 2,4,6‐Me₃C₆H₂; Cp* = C₅Me₅) by Reaction with DBU – Molecular Structure of [(DBU)H][Cp*TaCl₄] (DBU = 1,8‐diazabicyclo[5.4.0]undec‐7‐ene) [Cp*TaCl₄(PH₂R)] (R = Bu^t, Cy, Ad, Ph, 2,4,6‐Me₃C₆H₂ (Mes); Cp* = C₅Me₅) react with DBU in an internal redox reaction with formation of [(DBU)H][Cp*TaCl₄] ( 1 ) (DBU = 1,8‐diazabicyclo[5.4.0]undec‐7‐ene) and the corresponding diphosphane (P₂H₂R₂) or decomposition products thereof. 1 was characterised spectroscopically and by crystal structure determination. In the solid state, hydrogen bonding between the (DBU)H cation and one chloro ligand of the anion is observed.     

Vierkernige Clusterkomplexe vom Typ [MM′(AuPR3)2(μ‐H)(μ‐PCy2)(μ4‐PCy)(CO)6] (M,M′ = Mn,Re; R = Ph,Cy, Et): Synthese,Struktur und Topomerisierung

Tetranuclear Cluster Complexes of the Type [MM′(AuR₃)₂(μ‐H)(μ‐PCy₂)(μ₄‐PCy)(CO)₆] (M,M′ = Mn, Re; R = Ph, Cy, Et): Synthesis, Structure, and Topomerisation The dirhenium complex [Re₂(μ‐H)(μ‐PCy₂)(CO)₇(ax‐H₂PCy)] ( 1 ) reacts at room temperature in thf solution with each two equivalents of the base DBU and of ClAuPR₃ (R = Ph, Cy, Et) in a photochemical reaction process to afford the tetranuclear clusters [Re₂(AuPR₃)₂(μ‐H)(μ‐PCy₂)(μ₄‐PCy)(CO)₆] (R = Ph ( 2 ), Cy ( 3 ), Et ( 4 )) in yields of 35–48%. The homologue [Mn₂(μ‐H)(μ‐PCy₂)(CO)₇(ax‐H₂PCy)] ( 5 ) leads under the same reaction conditions to the corresponding products [Mn₂(AuPR₃)₂(μ‐H)(μ‐PCy₂)(μ₄‐PCy)(CO)₆] (R = Ph ( 6 ), Et ( 8 )). Also [MnRe(μ‐H)(μ‐PCy₂)(CO)₇(ax/eq‐H₂PCy)] ( 9 ) reacts under formation of [MnRe(AuPR₃)₂(μ‐H)(μ‐PCy₂)(μ₄‐PCy)(CO)₆] (R = Ph ( 10 ), Et ( 11 )). All new cluster complexes were identified by means of ¹H‐NMR, ³¹P‐NMR and ν(CO)‐IR spectroscopic measurements. 2 , 4 and 10 have also been characterized by single crystal X‐ray structure analyses with crystal parameters: 2 triclinic, space group P 1, a = 12.256(4) Å, b = 12.326(4) Å, c = 24.200(6) Å, α = 83.77(2)°, β = 78.43(2)°, γ = 68.76(2)°, Z = 2; 4 monoclinic, space group C2/c, a = 12.851(3) Å, b = 18.369(3) Å, c = 40.966(8) Å, β = 94.22(1)°, Z = 8; 10 triclinic, space group P 1, a = 12.083(1) Å, b = 12.185(2) Å, c = 24.017(6) Å, α = 83.49(29)°, β = 78.54(2)°, γ = 69.15(2)°, Z = 2. The trapezoid arrangement of the metal atoms in 2 and 4 show in the solid structure trans‐positioned an open and a closed Re…Au edge. In solution these edges are equivalent and, on the ³¹P NMR time scale, represent two fluxional Re–Au bonds in the course of a topomerization process. Corresponding dynamic properties were observed for the dimanganese compounds 6 and 8 but not for the related MnRe clusters 10 and 11 . 2 and 4 are the first examples of cluster compounds with a permanent Re–Au bond valence isomerization.     

Synthesis and Structural Characterization of Some Novel Trialkylsilyl‐substituted Lithium Benzyl Complexes [Li(tmeda)][CHRSiMe2R′] (R = Ph, 3,5‐Me2C6H3; R′ = Me,tBu, Ph)

The reactions of PhCH₂SiMe₃ ( 1 ), PhCH₂SiMe₂^tBu ( 2 ), PhCH₂SiMe₂Ph ( 3 ), 3,5‐Me₂C₆H₃CH₂SiMe₃ ( 4 ), and 3,5‐Me₂C₆H₃CH₂SiMe₂^tBu ( 5 ) with ⁿBuLi in tetramethylethylenediamine (tmeda) afford the corresponding lithium complexes [Li(tmeda)][CHRSiMe₂R′] (R, R′ = Ph, Me ( 6 ), Ph, ^tBu ( 7 ), Ph, Ph ( 8 ), 3,5‐Me₂C₆H₃, Me ( 9 ), and 3,5‐Me₂C₆H₃, ^tBu ( 10 )), respectively. The new compounds 5 , 7 , 8 , 9 and 10 have been characterized by ¹H and ¹³C NMR spectroscopy, compounds 7 , 8 and 9 also by X‐ray structure analysis.     

Tuning Ruthenium Carbene Complexes for Selective P−H Activation through Metal-Ligand Cooperation

The use of iminophosphoryl-tethered ruthenium carbene complexes to activate secondary phosphine P−H bonds is reported. Complexes of type [(p-cymene)-RuC(SO₂Ph)(PPh₂NR)] (with R = SiMe₃ or 4-C₆H₄−NO₂) were found to exhibit different reactivities depending on the electronics of the applied phosphine and the substituent at the iminophosphoryl moiety. Hence, the electron-rich silyl-substituted complex undergoes cyclometallation or shift of the imine moiety after cooperative activation of the P−H bond across the M=C linkage, depending on the electronics of the applied phosphine. Deuteration experiments and computational studies proved that cyclometallation is initiated by the activation process at the M=C bond and triggered by the high electron density at the metal in the phosphido intermediates. Consistently, replacement of the trimethylsilyl (TMS) group by the electron-withdrawing 4-nitrophenyl substituent allowed the selective cooperative P−H activation to form stable activation products.     

Syntheses,Characterizations, Crystal structures,and Antitumor Activities of Arenetelluronic Triorganotin Esters

Six new arenetelluronic triorganotin esters, namely (R₃Sn)₄[ArTe(μ‐O)(OH)O₂)]₂ (Ar = Ph, R = Me: 1 , R = Ph: 2 ; Ar = 3‐Me‐Ph, R = Me: 3 , R = Ph: 4 , Ar = 3‐Cl‐Ph, R = Me: 5 , R = Ph: 6 ), were prepared by treating arenetelluronic acids with the corresponding R₃SnCl (R = Me, Ph) with potassium hydroxide in methanol. All complexes were characterized by elemental analysis, FT‐IR, NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy, and X‐ray crystallography. The structural analyses indicate that these complexes are isostructural as Sn₄Te₂ moiety, in which the Te₂(μ₂‐O)₂ units are situated in the center and each Te atom is coordinated with two OSnR₃ groups on the side. Complexes 1 , 3 , and 5 show one‐dimensional chain and two‐dimensional network supramolecular structures by intermolecular C H···O or C H···Cl interactions. The antitumor activities of these complexes reveal that most arenetelluronic triorganotin esters have powerful antitumor activities with certain regularity.     

Homoleptische Amide von Zink,Cadmium und Quecksilber

Homoleptic Amides of Zinc, Cadmium, and Mercury ZnCl₂, CdCl₂ and HgCl₂ react with the lithium salts ( 1 a–5 a ) of the sterically demanding secundary amines HN(SiMe₃)Ph ( 1 ), HN(SiMe₃)C₆H₃Me₂‐2,6 ( 2 ), HN(SiMe₃)C₆H₃ⁱPr₂‐2,6 ( 3 ), HN(SiMe₃)C₆H₃^tBu₂‐2,5 ( 4 ), and HN(SiMe₂NMe₂)C₆H₃ⁱPr₂‐2,6 ( 5 ) yielding the corresponding homoleptic metal amides Zn[N(SiMe₂R′)R]₂ ( 1 b–5 b ), Cd[N(SiMe₂R′)R]₂ ( 1 c , 5 c ), and Hg[N(SiMe₂R′)R]₂ ( 1 d–5 d ), respectively. Except the dimeric {Zn[N(SiMe₃)Ph]₂}₂ ( 1 b ), all complexes are monomeric. The compounds were characterized by elemental analyses, molecular weight determinations, NMR and mass spectra. Furthermore, the zinc amides ( 1 b–5 b ) and the mercury amides 1 d–3 d and 5 d were characterized by single crystal X‐ray structure analysis. Except 1 b and 5 b , they show a linear N–M–N arrangement.     

Reaction of Carbon Anions With Iron α,β-Unsaturated Ketimine Complexes

Complexes (η⁴-PhCH=CHCR=NPh)Fe(CO)₃, where R=H(1a) and CH₃ were synthesized in excellent yield from the reaction of the corresponding α,β-unsaturated ketimines with excess Fe₂(CO)₉. Reaction of la with (Ph)₂CHLi and (CH₃)₂(NC)CLi at ?78°C or ambient temperature followed by acid quenching gave trans-PhCH=CHCHRNHPh, where R=CHPH₂ and C(CH₃)₂CN, respectively, in good yield. In the presence of 1 atm. of CO the reaction of 1a with (CH₃)₂(NC)CLi, followed by CuCl₂ oxidation resulted in the formation of a carbamyl choride, trans-PhCH=CHCH[C(CH₃)₂CN]N(Ph)COCl. This species was converted to a carbamate compound trans-PhCH=CHCH[C(CH₃)₂ - CN]N(Ph)COOCH₃ in MeOH in the presence of Ag⁺.     

Synthese,Struktur und Reaktivität von funktionalisierten Stibanidokomplexen des Eisens und Rutheniums [(η5-C5Me5)(CO)2MSbR1R2] (M = Fe,Ru; R1, R2 = SiMe3, C(O)tBu,C(O)Ph,C(O)-1 Ad)

Synthesis, Structure, and Reactivity of Functionalized Stibanido Complexes of Iron and Ruthenium [(η⁵-C₅Me₅)(CO)₂MSbR¹R²] (M = Fe, Ru; R¹, R² = SiMe₃, C(O) t Bu, C(O)Ph, C(O)-1 Ad) The reaction of equimolar amounts of [(η⁵-C₅Me₅)(CO)₂RuSb(SiMe₃)₂] ( 1 b ) and the carboxylic chlorides RC(O)Cl (R = tBu, Ph, 1-adamantyl) afforded the acyl(trimethylsilyl)stibanido complexes [(η⁵-C₅Me₅)(CO)₂RuSb · {C(O)R}(SiMe₃)] 2 b (R = tBu), 4 b (R = Ph), and 6 b (R = 1-Ad). The treatment of 1 b with two molar equivalents of pivaloyl chloride and benzoyl chloride led to the diacylstibanido complexes [(η⁵-C₅Me₅)(CO)₂RuSb{C(O)R}₂] ( 3 b , 5 b ). Analogously, the iron complex [(η⁵-C₅Me₅)(CO)₂FeSb · (SiMe₃)₂] ( 1 a ) is converted into the corresponding diacylstibanido complexes 3 a (R = tBu), 5 a (R = Ph) and 7 a (R = 1-Ad) by an excess of acid chloride. The treatment of 1 a with equimolar amounts of RC(O)Cl gave inseparable mixtures of starting material and the monoacyl- and diacyl stibanido complexes. Oxalyl chloride reacted quantitatively with two equivalents of 1 a to give complex [{(η⁵-C₅Me₅) · (CO)₂FeSb(SiMe₃)C(O)}₂] ( 8 ). The molecular structures of 1 a , 2 b and 5 b were elucidated by single crystal X-ray analyses.     

Diorganotin(IV) and triorganotin(IV) derivatives of diphenic acid

The diorganotin(IV) and triorganotin(IV) derivatives R₂SnA (R = Me, n-Pr, n-Bu, n-Oct) and (R₃Sn)₂A [R = Me, Ph, cyclohexyl (Cyh); A = an anion of diphenic acid] have been prepared and characterized by elemental analysis, IR, ¹H and ¹³C NMR spectroscopies. Tetrahedral tin forms a part of a diphenate cyclic ring in the diorganotin complexes with unidentate carboxylates, which have further been used for the synthesis of cyclic acid anhydrides. The soluble dinuclear triorganotin complexes (Me, Ph) possess symmetrically bonded carboxylates while the less soluble compound (Cyh₃Sn)₂A has two asymmetrically bonded carboxylates. All have a trigonal bipyramidal structure with R₃Sn units remote from each other.