Contributions to the chemistry of halosilane adducts: XVIII. On the nature of compounds of trimethylhalosilanes with 1,1,3,3-tetramethylguanidine and 2-trimethylsilyl-1,1,3,3-tetramethylguanidine: preparation and characterization of mono- and bis-(2-trimethylsilyl)-1,1,3,3-tetramethylguanidinium halides

1,1,3,3-Tetramethylguanidine (TMG) and 2-(trimethylsilyl)-1,1,3,3-tetramethylguanidine (TMSTMG) react with trimethylhalosilanes Me₃SiHal in equimolar ratio with ionization of the Sihalogen bond to give the stable guanidinium salts [(Me₂N)₂CNHSiMe₃]Hal (Hal  Cl (1), Br (2)) and [(Me₂N)₂CN(SiMe₃)₂]Hal (Hal  Cl (3), Br (4), I (5)), respectively, involving tetracoordinate silicon. No reaction occurs with Me₃SiF. The same ionic species are present in CHCl₃ or CH₃CN solutions (IR, ¹H, ²⁹Si NMR), thus establishing for the first time, the formation of an ionic solid derivative of Me₃SiCl stable towards dissociation. Reaction with an excess of TMG gives an equilibrium mixture of TMSTMG and TMG · HHal. The bis(silyl)guanidinium salts are less stable towards dissociation than the mono(silyl) derivatives, the stability sequence being Cl⁻ < Br⁻ < I⁻ within the series. The reactions of both types of compound have been investigated. The implications of the present and earlier results for the mechanisms of racemization and nucleophilic substitution at silicon are discussed.     

Spectroscopic and structural characterization of O,O′-(diphenylphosphineoxide)amidate and acetylacetonate complexes of pentacoordinate nickel(II)

Heteroleptic nickel pentacoordinate complexes with the macrocyclic ligands 2,4,4-trimethyl-1,5,9-triazacyclododec-1-ene (Me₃-mcN₃) or its 9-methyl derivative (Me₄-mcN₃), as ancillary ligands, and O,O′-(diphenylphosphineoxide)amidate ligands, [RC(O)NP(O)Ph₂]^¯ (R = C₆H₆ (1), C₅H₄N (2), C₄H₃S (3)), have been prepared as well as related acetylacetonate derivatives. The complexes have been studied by spectroscopic methods (IR, UV-Vis and ¹H NMR). In acetone solution, the complexes exhibit isotropically shifted ¹H NMR resonances. The full assignment of these resonances has been achieved using one- and two-dimensional ¹H NMR techniques. The single-crystal structures of {(Me₄-mcN₃)Ni[OP(Ph₂)NC(Tf)O]}[PF₆] (9) and {(Me₃-mcN₃)Ni(acac)}[PF₆] (10) have been established by X-ray diffraction.     

Reaction of iodo(trimethyl)silane with <Emphasis Type="Italic">N,N</Emphasis>-dimethyl carboxylic acid amides

The reactions of iodo(trimethyl)silane with N,N-dimethylformamide and N,N-dimethylacetamide Me₂NCOR (R = H, Me) at a molar ratio of 1: 2 involved mainly cleavage of the N-C(=O) bond with formation of up to 80% of N,N-dimethyltrimethylsilylamine Me₃SiNMe₂ and the corresponding acyl iodide RCOI. In the reaction with N,N-dimethylformamide, formyl iodide HCOI was detected for the first time by gas chromatography-mass spectrometry. The contribution of Me-N bond cleavage, leading to N-methyl-N-trimethylsilyl derivative Me(Me₃Si)NCOR and methyl iodide was considerably smaller. Another by-product was the corresponding N-methyl imide MeN(COR)₂ formed by reaction of the initial amide with acyl iodide. The primary intermediate in the reaction of iodo(trimethyl)silane with DMF and DMA is quaternary ammonium salt [Me₂(Me₃Si)N⁺COR] I⁻ which decomposes via dissociation of the N-CO and N-Me bonds.     

Synthesis and conformational analysis of 1,3-azasilinanes

1-Isopropyl-3-methyl-3-phenyl-1,3-azasilinane 1 and 1-isopropyl-3,3-dimethyl-1,3-azasilinane 2 were synthesized and a detailed analysis of their NMR spectra, conformational equilibria and ring inversion processes is presented. Low temperature ¹H/¹³C NMR spectroscopy, iteration of the ¹H NMR spectra and quantum chemical calculations showed slight predominance of the Ph_eqMe_ax over the Ph_axMe_eq conformer of 1 at low temperature. The barrier for the chair to chair interconversion of both compounds was measured to be 8.25 kcal/mol.     

Rare‐Earth‐Metal Methyl,Amide, and Imide Complexes Supported by a Superbulky Scorpionate Ligand

The reaction of monomeric [(Tp^tBu,Me)LuMe₂] (Tp^tBu,Me=tris(3‐Me‐5‐tBu‐pyrazolyl)borate) with primary aliphatic amines H₂NR (R=tBu, Ad=adamantyl) led to lutetium methyl primary amide complexes [(Tp^tBu,Me)LuMe(NHR)], the solid‐state structures of which were determined by XRD analyses. The mixed methyl/tetramethylaluminate compounds [(Tp^tBu,Me)LnMe({μ₂‐Me}AlMe₃)] (Ln=Y, Ho) reacted selectively and in high yield with H₂NR, according to methane elimination, to afford heterobimetallic complexes: [(Tp^tBu,Me)Ln({μ₂‐Me}AlMe₂)(μ₂‐NR)] (Ln=Y, Ho). X‐ray structure analyses revealed that the monomeric alkylaluminum‐supported imide complexes were isostructural, featuring bridging methyl and imido ligands. Deeper insight into the fluxional behavior in solution was gained by ¹H and ¹³C NMR spectroscopic studies at variable temperatures and ¹H–⁸⁹Y HSQC NMR spectroscopy. Treatment of [(Tp^tBu,Me)LnMe(AlMe₄)] with H₂NtBu gave dimethyl compounds [(Tp^tBu,Me)LnMe₂] as minor side products for the mid‐sized metals yttrium and holmium and in high yield for the smaller lutetium. Preparative‐scale amounts of complexes [(Tp^tBu,Me)LnMe₂] (Ln=Y, Ho, Lu) were made accessible through aluminate cleavage of [(Tp^tBu,Me)LnMe(AlMe₄)] with N,N,N′,N′‐tetramethylethylenediamine (tmeda). The solid‐state structures of [(Tp^tBu,Me)HoMe(AlMe₄)] and [(Tp^tBu,Me)HoMe₂] were analyzed by XRD.     

Derivatives of cyclotetrazenoborane (tetrazoborol-2-ine)—VI.1 Mass spectra of B substituted cyclotetrazenoboranes

The mass spectra of B substituted 2,5-dimethyl cyclotetrazenoboranes have been studied. The compounds Me₂N₄BD, Me₂N₄BEt, Me₂N₄BVi, Me₂N₄BCl and Me₂N₄BBr give confirmatory evidence that loss of N₂+H^. from the system occurs by loss of H from the side chain and that the B? R bond is very stable under electron impact conditions. Fragmentation proceeds in a similar fashion to that of the 2,5-dimethyl substituted compounds with H bonded to the boron atom.     

Trifluoromethanesulfonate (triflate) as a moderately coordinating anion: Studies from chemistry of the cationic coordinatively unsaturated mono- and diruthenium amidinates

Triflate complexes of mono- and diruthenium amidinates, (η⁶-C₆R₆)Ru(κ¹-OTf){η²-R′NC(R′′)NR′} (1: R = Me; 2: R = H) and (η⁵-C₅Me₅)Ru(μ-η²-ⁱPrNC(Me)NⁱPr)Ru(κ¹-OTf)(η⁵-C₅R₅) (3: R = Me; 4: R = H), are synthesized, and coordination behavior of the triflate anion to the coordinatively unsaturated ruthenium species is investigated by crystallography and variable temperature (VT) NMR spectroscopy (¹⁹F, ¹H). The monoruthenium amidinate complexes have three-legged piano-stool structures in single crystals, which include a κ¹-OTf ligand with the Ru–O bond of 2.15–2.20 Å. In contrast, reversible dissociation of OTf is observed in variable temperature ¹H NMR spectroscopy in liquid states; the activation energy for the dissociation and recombination of the OTf ligand is varied with the substituents on the arene and amidinate ligand in the corresponding ruthenium cation and the solvent used. A typical example of moderately coordinating ability of the OTf ligand is seen in ¹⁹F NMR spectra of (η⁶-C₆Me₆)Ru(κ¹-OTf){η²-ⁱPrNC(Me)NⁱPr} (1a) and (η⁶-C₆H₆)Ru(κ¹-OTf){η²-ⁱPrNC(Me)NⁱPr} (2a) in CD₂Cl₂ at the temperature range from −90 to 20 °C, in which the OTf anion is dissociated in 1a, whereas 2a has a relatively robust Ru–OTf bond. Combination of crystallography and VT NMR contributes to understanding the difference in coordination behavior of the OTf ligand between two diruthenium amidinates, (η⁵-C₅Me₅)Ru(μ-η²-ⁱPrNC(Me)NⁱPr)Ru(κ¹-OTf)(η⁵-C₅Me₅) (3) and (η⁵-C₅Me₅)Ru(μ-η²-ⁱPrNC(Me)NⁱPr)Ru(κ¹-OTf)(η⁵-C₅H₅) (4); the results suggest that the electron-donating and sterically demanding η⁵-C₅Me₅ helps for dissociation of the triflate ligand. Moderate coordinating ability of the triflate anion sometimes provides characteristic reactions of mono- and diruthenium amidinates which differ from the corresponding neutral halogeno-compounds or cationic coordinatively unsaturated homologues bearing fluorinated tetraarylborates; a typical example is given by inhibition of coordination of ethylene to the [(η⁶-C₆H₆)Ru{η²-^tBuNC(Ph)N^tBu}]⁺ species by the OTf ligand.     

Reaktionen von metall-koordiniertem kohlenmonoxid mit yliden: XVII. Darstellung eines molybdän- und wolframkomplexes mit η3-gebundenem trimethylsiloxybutenon-liganden durch silylierung der phosphonium-metall-enolat-vorstufe

The reaction of the phosphonium metallates Me₄P[C₅R₅(CO)(Me₃P)$\text{MC(O)=CHC(O}$)R′] (M = W, R = H, R′ = Et (1a); M = Mo, R = Me, R′ = Me (1b)) with the silylating reagent Me₃SiOSO₂CF₃ yields the neutral complexes C₅R₅(CO)(Me₃P)$\text{MC(OSiMe}{}_3\text{)=CHC(O}$)R (2a, 2b) bearing a chelating O(2), C(4)-trimethylsiloxybutenone ligand. The structure of the new compounds is established by the IR, ¹H and ³¹P NMR spectra.     

Triorganoantimony(V) carboxylates: Synthesis, characterization and crystal structure of [Me3Sb(O2C-C5H4N)2] · H2O

Reactions of [R₃Sb(OPrⁱ)₂] with N-heterocylic carboxylic acids gave compounds of the type [R₃Sb(O₂C-Ar)₂] (1) (R = Me, Et, Prⁱ, Ph; Ar = 2-C₅H₄N, 2-C₉H₆N). The mono-bromo compound [Me₃Sb(Br)(O₂C-C₅H₄N)] (2) exists in equilibrium with [Me₃Sb(O₂C-C₅H₄N)₂] and [Me₃SbBr₂]. All new compounds have been characterized by IR and NMR (¹H and ¹³C{¹H}) spectral data. X-ray structural analysis of one example, [Me₃Sb(O₂C-C₅H₄N)₂], isolated as its monohydrate, revealed an essentially trigonal bipyramidal geometry for the antimony atom defined by three equilaterally disposed methyl groups and two oxygen atoms from monodentate carboxylate groups, in apical positions. The crystal structure is consolidated into a three-dimensional network by cooperative O-H?O, O-H?N and C-H?O interactions.     

Synthesis, characterization, and molecular structures of di- and triorganotin(IV) complexes with 9-anthracenecarboxylic acid: The structural diversity in organotin 9-anthracenecarboxylates

The di- and triorganotin(IV) derivatives of anthracenecarboxylic acid, Ph₂MeSnOC(O)C₁₄H₉ (2), Me₃SnOC(O)C₁₄H₉ (3), Me₂Sn[OC(O)C₁₄H₉]₂ · CH₃OH (4) Ph₃SnOC(O)C₁₄H₉ · CH₃OH (5), Ph₂EtSnOC(O)C₁₄H₉ (6), Ph₂Sn[OC(O)(C₁₄H₉)]₂ (7) and PhMe₂SnOC(O)C₁₄H₉ (8) were synthesized by the reaction of Ph₂MeSnI, Me₃SnCl, Me₂SnCl₂, Ph₃SnCl, Ph₂EtSnI, Ph₂SnCl₂, and PhMe₂SnI with 9-anthracenecarboxylic acid, respectively, with the aid of potassium iso-propoxide. All complexes were characterized by elemental analysis, mass spectrometry, IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopes. The molecular structures of complexes 2, 3 and 4 were determined by single crystal X-ray analysis. The X-ray structures reveal that complex 2 and 3 adopt a polymeric trans-C₃SnO₂ trigonal bipyamidal configuration with the oxygen atoms occupying axial positions. Complex 4 adopts a monomeric structure with two carboxylates coordinated to tin in a monodentate form from axial and equatorial positions, and with the coordination number raised to five as the methanol occupies the apical position of the trigonal bipyramid.     

Synthesis and Characterisation of 1‐[9‐(H,Me3Si,Me3Ge,Me3Sn)9‐Fluorenyl]‐3,7,10‐trimethylgermatranes. The Crystal Structure Analysis of 1‐(9‐Fluorenyl)‐3,7,10‐trimethylgermatrane

The title compounds, viz. C₁₃H₈(R)Ge · (OCHMeCH₂)₃N ( 1 : R = H, 2 : R = Me₃Si; 3 : R = Me₃Ge) were prepared as mixtures of diastereomers by the reaction of N(CH₂CHMeOSnAlk₃)₃ ( 7 : Alk = Et; 8 : Alk = Bu) with C₁₃H₈(R)GeBr₃ ( 4 : R = H, 5 : R = Me₃Si; 6 : R = Me₃Ge), respectively. The synthesis of C₁₃H₈(Me₃Sn)Ge · (OCHMeCH₂)₃N ( 13 ) by the reaction of germatrane ( 1 ) with Me₃SnNMe₂ is reported. Identity and structures were established by elemental analyses, ¹H and ¹³C NMR spectroscopy and mass spectrometry. The crystal structure of 1 was determined by X‐ray diffraction methods.     

Synthesis, structural characterization and reactivity of new tin bridged ansa-bis(cyclopentadiene) compounds: X-ray crystal structures of Me2Sn(C5Me4R-1)2 (R = H, SiMe3)

The organo-tin compounds, Me₂Sn(C₅H₄R-1)₂ (R = Me (1), Prⁱ (2), Bu^t (3), SiMe₃ (4)) and Me₂Sn(C₅Me₄R-1)₂ (R = H (5), SiMe₃ (6)), were prepared by the reaction of Me₂SnCl₂ with the lithium or sodium derivative of the corresponding cyclopentadiene. Compounds 1-6 have been characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ¹¹⁹Sn). In addition the molecular structures of 5 and 6 were determined by single crystal X-ray diffraction studies. The transmetalation reaction of 1-6 with ZrCl₄ or [NbCl₄(THF)₂] gave the corresponding metallocene complexes in high yields.     

Heavier alkali metal complexes of the bulky alkyl ligand 2-(bis(trimethylsilyl)methyl)-6-methylpyridine: Crystal structures of [{6-Me(2 Pyr)}(Me3Si)2CNa(pmdta)] and [{6-Me(2-Pyr)}(Me3Si)2CK]∞

Reaction of the bulky pyridyl based ligand 6-Me(2-Pyr)(Me₃Si)₂CH with ⁿBuM (M = Na, K) in the presence of the N donors pmdta (N,N′,N′,N″,N″ pentamethyldiethylenetriamine) and tmeda (N,N,N′,N′ tetramethylethylenediamine) resulted in the formation and crystallisation of the heavy alkali metal complexes, [{6-Me(2-Pyr)}(Me₃Si)₂CNa(pmdta)], 1, and [{6-Me(2-Pyr)}(Me₃Si)₂CK]_∞, 2. Single crystal X-ray diffraction studies show the sodium complex, 1, to be monomeric with a six coordinate metal centre, while the unsolvated potassium complex, 2, is polymeric, involving repeating η³ 1-aza-allyl and allylic interactions of the pyridyl moiety with the potassium cation.     

Neutral penta-coordinated diorganotin(IV) complexes derived from ortho-aminophenol Schiff bases: Synthesis, characterization and molecular structures

The one pot reactions carried among ortho-aminophenol, R₂SnO (R = Me or Ph) and acetyl acetone, 2-hydroxyacetophenone and 2-hydroxy-3-methylacetophenone led to six new diorganotin(IV) compounds Me₂SnL1 (1), Ph₂SnL1 (2), Me₂SnL2 (3) Ph₂SnL2 (4), Me₂SnL3 (5) and Ph₂SnL3 (6) (H2L1 = 2-(3-hydroxy-1-methyl-but-2-enylideneamino)-phenol, H2L2 and H2L3 = 2-[1-(2-hydroxyaryl)alkylideneamino]-phenol) in good yields. Combination of IR, ¹H, ¹³C and ¹¹⁹Sn NMR and X-ray diffraction techniques along with elemental analyses evidenced the formation of penta-coordinated monomeric species. The crystal structures of ligand H2L1 and complexes 1, 3 and 4 were determined by single crystal X-ray diffraction study. In the solid state, the ligand H2L1 exists as keto-enamine tautomeric form. There are N-H…O intra-molecular hydrogen bonds between amine and carbonyl groups. Diorganotin(IV) complexes 1, 3 and 4 are monomers with TBP (trigonal bipyramidal) geometry surrounding the tin atom. The O, N, O- tridentate ligand places its two oxygen donating atoms in the axial positions, and the nitrogen atom occupies one equatorial position. The two R groups attached to tin occupy the other two equatorial positions. The solution structures were predicted by ¹¹⁹Sn NMR spectroscopy.     

Synthesis and structures of organoantimony compounds containing intramolecular Sb-N interactions

Stibines containing the pendant arm [2-(Me₂NCHR)C₆H₄] (where R = H or Me) were synthesized, and their reactions with CH3I and HBr have been carried out to obtain the diammonium salt {[2-(Me₂NCHR)C₆H₄] [2-(Me₃N⁺CHR)C₆H₄]}Sb 2[I]⁻ (where R = H 3; Me 4) and triammonium salt {2-[(Me₂HN⁺CH₂)C₆H₄]₃}Sb 3[Br]⁻5, respectively. A novel platinum complex 6 [PtCl₂ · 1] containing stibine 1 as a bidentate ligand has also been prepared. All these compounds show Sb-N interactions. A good conjunction was observed between semi-empirical method and ¹H and ¹³C NMR (at different temperature) data for the diammonium salts of compounds 3 and 4. The structures of all the synthesized compounds were determined by X-ray diffraction analyses. This appears to be the second molecular structure of a Pt stibine complex containing a Pt-Cl bond trans to stibine ligand, as few Pt-Sb X-ray structures are known.     

Hydro- and chloro-substituted silyl- and silyl-η-amido-η-tetramethylcyclopentadienyl titanium complexes

Chlorosilyl-cyclopentadienyl titanium precursors [Ti(η⁵-C₅Me₄SiMeXCl)Cl₃] (X=H 2, Cl 3) were prepared by reaction of TiCl₄ with the trimethylsilyl derivatives of the corresponding cyclopentadienes. Methylation of these compounds with MgClMe under appropriate conditions afforded the methyl complexes [Ti(η⁵-C₅Me₄SiMe₂R)XMe₂] (R=H, X=Cl 5, Me 6; R=X=Me 7). Reactions of 2 and 3 with two equivalents of LiNH^tBu afforded the ansa-silyl-η-amido compounds [Ti{η⁵-C₅Me₄SiMeX(η¹-N^tBu)}Cl₂] (X=H 8, Cl 9). Methylation of 8 gave [Ti{η⁵-C₅Me₄SiMeH(η¹-N^tBu)}Me₂] 10. Complex 9 was also obtained by reaction of 8 with BCl₃, whereas the same reaction using alternative chlorinating agents (TiCl₄, HCl) resulted in deamidation to give 2, which was also converted into 3 by reaction with BCl₃. All of the new compounds were characterized by NMR spectroscopy and the molecular structures of 2 and 4 were determined by X-ray diffraction methods.     

Binding H2, N2, H-, and BH3 to transition-metal sulfur sites: synthesis and properties of [RuL(PR3)(N2Me2S2)] Complexes (L=eta2-H2, H-, BH3; R=Cy, iPr)

The reactions of [Ru(N₂)(PR₃)(‘N₂Me₂S₂’)] [‘N₂Me₂S₂’=1,2‐ethanediamine‐N,N′‐dimethyl‐N,N′‐bis(2‐benzenethiolate)(2?)] [ 1 a (R=iPr), 1 b (R=Cy)] and [μ‐N₂{Ru(N₂)(PiPr₃)(‘N₂Me₂S₂’)}₂] ( 1 c ) with H₂, NaBH₄, and NBu₄BH₄, intended to reduce the N₂ ligands, led to substitution of N₂ and formation of the new complexes [Ru(H₂)(PR₃)(‘N₂Me₂S₂’)] [ 2 a (R=iPr), 2 b (R=Cy)], [Ru(BH₃)(PR₃)(‘N₂Me₂S₂’)] [ 3 a (R=iPr), 3 b (R=Cy)], and [Ru(H)(PR₃)(‘N₂Me₂S₂’)]^? [ 4 a (R=iPr), 4 b (R=Cy)]. The BH₃ and hydride complexes 3 a , 3 b , 4 a , and 4 b were obtained subsequently by rational synthesis from 1 a or 1 b and BH₃?THF or LiBEt₃H. The primary step in all reactions probably is the dissociation of N₂ from the N₂ complexes to give coordinatively unsaturated [Ru(PR₃)(‘N₂Me₂S₂’)] fragments that add H₂, BH₄^?, BH₃, or H^?. All complexes were completely characterized by elemental analysis and common spectroscopic methods. The molecular structures of [Ru(H₂)(PR₃)(‘N₂Me₂S₂’)] [ 2 a (R=iPr), 2 b (R=Cy)], [Ru(BH₃)(PiPr₃)(‘N₂Me₂S₂’)] ( 3 a ), [Li(THF)₂][Ru(H)(PiPr₃)(‘N₂Me₂S₂’)] ([Li(THF)₂]‐ 4 a ), and NBu₄[Ru(H)(PCy₃)(‘N₂Me₂S₂’)] (NBu₄‐ 4 b ) were determined by X‐ray crystal structure analysis. Measurements of the NMR relaxation time T₁ corroborated the η² bonding mode of the H₂ ligands in 2 a (T₁=35 ms) and 2 b (T₁=21 ms). The H,D coupling constants of the analogous HD complexes HD‐ 2 a (¹J(H,D)=26.0 Hz) and HD‐ 2 b (¹J(H,D)=25.9 Hz) enabled calculation of the H? D distances, which agreed with the values found by X‐ray crystal structure analysis ( 2 a : 92 pm (X‐ray) versus 98 pm (calculated), 2 b : 99 versus 98 pm). The BH₃ entities in 3 a and 3 b bind to one thiolate donor of the [Ru(PR₃)(‘N₂Me₂S₂’)] fragment and through a B‐H‐Ru bond to the Ru center. The hydride complex anions 4 a and 4 b are extremely Brønsted basic and are instantanously protonated to give the η²‐H₂ complexes 2 a and 2 b .     

Coordination polymers based on building blocks of dimethyltin(IV) Chloride iso‐thiocyanate and dimethyltin(IV) di‐iso‐thiocyanate with pyrazine‐2‐carboxylate and 4, 4′‐bipyridine

The reaction of 4,4′‐bipy with dimethyltin(IV) chloride iso‐thiocyanate affords the one‐dimensional (1D) coordination polymer, [Me₂Sn(NCS)Cl·(4,4′‐bipy)]_n ( 1 ), whereas reaction of dimethyltin(IV) dichloride with sodium pyrazine‐2‐carboxylate in the presence of potassium iso‐thiocyanate affords the two‐dimensional (2D) coordination polymer, {[Me₂Sn(C₄H₃N₂COO)₂]₂ [Me₂Sn(NCS)₂]}_n ( 2 ). Both coordination polymers were characterized by elemental analysis and infrared spectroscopy in addition to ¹H and ¹³C NMR spectroscopy of the soluble coordination polymer ( 1 ). A single‐crystal structure determination showed that the asymmetric unit in 1 contains Me₂Sn(NCS)Cl and 4,4′‐bipy moieties and a 1D infinite rigid chain structure forms through bridging of the 4,4′‐bipy ligand between tin atoms and the geometry around the tin atom is a distorted octahedral. Coordination polymer 2 contains two distinct tin atom geometrics in which one tin atom is seven coordinate, and the other is six coordinate. The two tin atom environments are best described as a pentagonal bipyramidal in the former and distorted octahedral in the latter where the carboxylate groups bridge the two tin atoms and construct a 2D‐coordination polymer. The ¹¹⁹Sn NMR spectroscopy indicates the octahedral geometry of 1 retains in solution. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:699–706, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/.20736     

Intramolekulare Cyclisierung von terminal disubstituierten α, ω-Diinen an Titanocen “Cp2Ti” mit einer nachfolgenden, ungewöhnlichen Cp-ringöffnung und neuen intramolekularen C---C-Knüpfung

The reaction of Cp₂Ti(Me₃SiC₂SiMe₃) (1) with terminal disubstituted α,ω-diynes RC≡C---(CH₂)_n---C≡CR affords, after substitution of Me₃SiC₂SiMe₃, bicyclic titanacyclopentadienes via intramolecular cyclization. The stability of the obtained products 2, 3 and 5 is determined by the spacer length (n = 2, 4, 5, 6). The four-membered ring derivatives (n = 2) 2a and 2b were obtained in good yield. In the case of n = 4 the bicyclic six-membered ring 3 was formed at first, which rearranges to a stable tricyclic η⁴:η³-dihydroindenyl-Ti complex 4 by Cp cleavage and intramolecular C---C coupling. Complex 4 was characterized by X-ray structure analysis and NMR spectroscopy. An increase of spacer length (n > 4) provides indefinable secondary and decomposition products.

Zusammenfassung

Bei der Umsetzung von Cp₂Ti(Me₃SiC₂SiMe₃) (1) mit terminal disubstituierten α, ω-Diinen RC≡C---(CH₂)_n---C≡CR erhält man nach Substitution des Me₃SiC₂SiMe₃ in Abhängigkeit von der Spacerlänge (n = 2, 4, 5, 6) über eine intramolekulare Cyclisierung die unterschiedlich stabilen bicyclischen Titanacyclopentadiene 2, 3 and 5. In guten Ausbeuten lassen sich die 4-Ring-Derivate (n = 22a und 2b isolieren. Im Falle von n = 4 entsteht zunächst das bicyclische 6-Ring-System 3, das sich durch Cp-Spaltung und intramolekulare C---C-Knüpfung in den stabilen tricyclischen η⁴:η³-Dihydroindenyl-Titan-Komplex4 umlagert. Komplex 4 wurde durch Röntgenstrukturanalyse und NMR-Spektroskopie charakterisiert. Eine Erhöhung der Spacerlänge (n > 4) führt zu undefinierbaren Folge- und Zersetzungsprodukten.     

Properties of η-pentamethylcyclopentadienyl rhodium(III) and iridium(III) complexes with quinolin-8-ol and their cytostatic activity

Reaction of dimers [M(η⁵-C₅Me₅)Cl₂]₂ (M-Rh, Ir) with quinolin-8-ol in molar ratio 1:2 leads to formation of monomer complexes [Rh(η⁵-C₅Me₅)Cl(qol)] (1) and [Ir(η⁵-C₅Me₅)Cl(qol)] (2) (qol = quinolin-8-olate). Compounds 1 and 2 have been characterized with elemental analysis and spectroscopic methods. ¹H NMR spectra revealed that quinolin-8-olate is coordinated via oxygen and nitrogen atoms. The ¹H NMR and ¹³C NMR spectra showed that carbon and hydrogen atoms of pentamethylcyclopentadienyl ligand are equivalent. The structure of rhodium complex has been calculated using DFT B3LYP method. The calculated geometry of complex 1 agrees very well with data found for rhodium complexes containing Cl, C₅Me₅ and qol ligands. Both complexes are active antitumor and antibacterial agents.