Dimorpholinoacetylene and Its Use for the Synthesis of Tetraaminocyclobutadiene Species

The new diaminoacetylene (DAA) dimorpholinoacetylene ( 3 ) was prepared from 1,1-dimorpholinoethene ( 1 ) by bromination to form the dibromoketene aminal 2 , which upon lithiation afforded 3 through a Fritsch-Buttenberg-Wiechell rearrangement. Heating 3 at elevated temperatures resulted in a complete conversion into the dimer 1,1,2,4-tetramorpholino-1-buten-3-yne ( 4 ), which was used for the synthesis of four-membered cyclic bent allene (CBA) transition-metal complexes of the type [(CBA)ML_n] ( 5 - 7 ; ML_n=AuCl, RhCl(COD), RhCl(CO)₂; CBA=1,3,4,4-tetramorpholino-1,2-cyclobutadiene; COD=1,5-cyclooctadiene). The reaction of 3 with tetraethylammonium bromide gave 1,2,3,4-tetramorpholinocyclobutenylium bromide ( 8 ), which reacted with bromine to form 1,2,3,4-tetra(morpholino)cyclobutenediylium bis(tribromide) ( 9 ). Compound 9 represents the first fully characterized compound containing a tetraaminocyclobutadiene dication and displays a nearly planar C₄N₄ core as shown by X-ray diffraction analysis. Detailed quantum chemical calculations were performed to assess the aromaticity of tetraaminocyclubutadiene dications by employing the Nucleus Independent Chemical Shift (NICS) method and current density analysis.     

Ge4Cl4[MCp(CO)3]4 (M = Cr,Mo, W): A Series of Transition Metal Substituted Four-membered Cyclogermanes

The reaction of GeCl₂ · dioxane with the sodium salts NaMCp(CO)₃ (M = Cr, Mo, W) leads to new four-membered ring compounds Ge₄Cl₄[MCp(CO)₃]₄, where the remaining chlorine atom cannot be substituted by another MCp(CO)₃ substituent. A large excess of the sodium salts only leads to some minor side-reactions. All Ge₄-compounds exhibit a non-planar four-membered Ge₄ ring, which can be traced back to electrostatic effects as shown by quantum chemical calculations. Furthermore, cluster build-up reactions might be possible due to the halide substituents in the new ring compounds of germanium, showing that GeCl₂ · dioxane is an excellent starting material for the synthesis of cluster compounds of germanium.     

Isolation of an Imino‐N‐heterocyclic Carbene/Germanium(0) Adduct: A Mesoionic Germylene Equivalent

An autoionization of germanium dichloride/dioxane complex with an imino‐N‐heterocyclic carbene ligand ( L ) afforded a novel germyliumylidene ion, [( L )GeCl]⁺[GeCl₃]^?, which was fully characterized. Reduction of the germyliumylidene ion with potassium graphite produced a cyclic species [( L )Ge], which can be viewed as both a Ge⁰ species and a mesoionic germylene. X‐ray diffraction analysis and computational studies revealed one of the lone pairs on the Ge atom is involved in the π system on the GeC₂N₂ five‐membered ring. It was also confirmed that the nucleophilic behavior of [( L )Ge] as a two lone‐pair donor.     

A new versatile binuclear seven-coordinate complex of molybdenum(II), [(μ-Cl)2{Mo(μ-Cl)(SnCl3)(CO)3}2]

The two new seven-coordinate anionic complexes of molybdenum(II), binuclear [(μ-Cl)₂{Mo(μ-Cl)(SnCl₃)(CO)₃}₂]²⁻ and mononuclear [MoCl₃(GeCl₃)(CO)₃]²⁻, have been synthesized and characterized by single-crystal X-ray diffraction studies. The binuclear complex exhibits a unique mode of reactivity towards norbornene. In a strictly anhydrous atmosphere the binuclear complex effectively initiates the ring-opening metathesis polymerization reaction of norbornene, but in the presence of water norbornene is efficiently transformed to the binorbornyl ether (C₇H₁₁)₂O.     

Reactions of germanium(II), tin(II), and antimony(III) chlorides with acenaphthene-1,2-diimines

Reactions of diimines dtb-BIAN and dph-BIAN with GeCl₂ afford germanium(II) complexes with radical-anionic ligands, (dtb-BIAN)GeCl (5) and (dph-BIAN)GeCl (6a), respectively, where dtb-BIAN is 1,2-bis[(2,5-di-tert-butylphenyl)imino]acenaphthene and dph-BIAN is 1,2-bis[(2-biphenyl)imino]acenaphthene. The latter reaction gives 6a along with [(dph-BIAN)GeCl]⁺[GeCl₃]⁻ (6b). The reactions of tin(II) and antimony(III) chlorides with dtb-BIAN and dpp-BIAN produce complexes of these halides with neutral coordinated diimines, viz., (dtb-BIAN)SnCl₂ (7) and (dpp-BIAN)SbCl₃ (8) (dpp-BIAN is 1,2-bis[(2,6-di-isopropylphenyl)imino]acenaphthene). Paramagnetic complexes 5 and 6a were studied by ESR spectroscopy. Diamagnetic compounds 7 and 8 were characterized by ¹H NMR spectroscopy. The structures of complexes 5, 6a,b, 7, 8, and (dpp-BIAN)Ge (9) were established by X-ray diffraction analysis. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 71–80, January, 2006.     

119Sn- and 31P-NMR. Spectroscopy of the 5-coordinate complexes [Rh (SnClnBr(3−n)) (norbornadiene) (tertiary phosphine)2]

The products of the reaction of [RhCl (NBD)]₂ (NBD = norbornadiene), with four equivalents tertiary phosphine and two equivalents of tin (II) bromide have been studied by ¹¹⁹Sn- and ³¹P-NMR. spectroscopy. The solution data suggest that halogen scrambling occurs during the preparation and results in a mixture of complexes containing SnBr₃, SnClBr₂, and SnCl₂Br and SnCl₃ ligands, and this is confirmed by independent synthesis of the SnCl₃ and SnBr₃ complexes. The metalmetal coupling constants, ¹J (¹¹⁹Sn, ¹⁰³Rh), vary from 452 to 580 Hz and are linearly related to: (a) δ(¹¹⁹Sn) in the complexes [Rh (SnCl_nBr_(3-n))NBD (PEtPh₂)₂] and (b) the sum of the Pauling electronegativities for the halogens on tin.     

Complexes amines du rhodium(I) : I. Complexes du type chloro-monoamine cyclooctadiène- 1,5 rhodium(I) et leurs produits de réaction avec l''oxyde de carbone

The reaction of amines with [(RhClCod)₂] (Cod = 1,5-cyclooctadiene) gives monomeric compounds [RhCl(Am)Cod](Am = amine). Elementary analyses as well as IR and NMR spectra are consistent with their structure.On treatment with carbon monoxide at atmospheric pressure these compounds give a series of complexes, [RhCl(Am)(CO)₂], identified by elementary analyses and IR spectra.The thermolysis of [RhCl(Aam)(CO)₂] with Aam = allyamine gives [{RhCl(Aam)CO_n}] not perfectly isolated. The reaction of [{RhCl(CO)₂}₂] with 2-vinylpyridine leads to the same kind of compound [{RhCl(Vpy)CO_m}] with Vpy = 2 -vinylpyridine. This latter complex is identified by elementary analysis. The IR spectra of these two complexes show that the olefinic double bond of amines β,γ-insaturated interacts with a rhodium atom. Their properties are discussed.     

Darstellung und Konfiguration von Tricarbonylchromat-Anionen mit SnCl3− und GeCl3− als Liganden

B₃N₃Me₆Cr(CO)₃ reacts with [AsPh₄] [SnCl₃] and [AsPh₄] [GeCl₃] in tetrahydrofuran to give [AsPh₄]₃[Cr(CO)₃(SnCl₃)₃] and [AsPh₄]₃[Cr(CO)₃(GeCl₃)₃], respectively. According to IR. and ¹³C-NMR.-data, the tricarbonylate anions possess a meridional configuration. The donor-acceptor properties of SnCl₃^? and GeCl₃^? in the anions [Cr(CO)₃(ECl₃)₃]^3? (E = Sn, Ge) are very similar. A similar synthesis of [AsPh₄]₃[Cr(CO)₃(SnF₃)₃] was not successful.     

Stannylene complexes of manganese,iron, and platinum

A number of stannylene complexes with different M: Sn ratios were obtained using various metals and substituents at the tin atom. The structures of the complexes were examined. A reaction of CpMn(CO)₂THF with (Ph₄As)⁺(SnCl₃)^? gave the ionic complex [Ph₄As]⁺[CpMn(CO)₂SnCl₃]^? (I). The action of C₆F₅MgBr on the complex C₅H₅Mn(CO)(NO)SnCl₃ produced C₅H₅Mn(CO)(NO)Sn(C₆F₅)₃ (II). Replacement of the Cl ions in the complex [CpFe(CO)₂]₂SnCl₂ by phenylacetylenide groups gave rise to the neutral complex [CpFe(CO)₂]₂Sn(C≡CPh)₂ (III). A reaction of (Dppm)PtCl₂ (Dppm is 1,1-bis(diphenylphosphino)methane) with SnCl₂ · 2H₂O in the presence of diglyme yielded the ionic complex [η³-CH₃O(CH₂)₂O(CH₂)₂OCH₃)SnCl]⁺[(η ²-Dppm)Pt(SnCl₃)₃]^? (IV). Transmetalation in a reaction of [(Dppe)₂CoCl][SnCl₃] · PhBr (Dppe is 1,2-bis(diphenylphosphino)ethane) with (Dcpd)PtCl₂ (Dcpd is dicyclopentadiene) in the presence of SnCl₂ afforded the ionic complex [Pt(Dppe)₂]₃[Pt(SnCl₃)₅]₂ (V). Structures I–V were identified by X-ray diffraction. In these structures, the formally single bonds between the atoms of transition metals M (Mn, Fe, and Pt) and Main Group heavy elements (Sn and P) having vacant d orbitals are appreciably shortened. The M-Sn bond length in complexes II and III are virtually independent of the substituents at the tin atom and the Pt-Sn bond length in complexes IV and V is virtually independent of the Pt: Sn ratio.     

1,1,3,3-Tetrakis(dimethylamino)-1λ5,3λ5-diphosphet als Ligand in Koordinationsverbindungen

1,1,3,3-Tetrakis(dimethylamino)-1λ⁵,3λ⁵-diphosphete as Ligand in Coordination Compounds 1,1,3,3-Tetrakis(dimethylamino)-1λ⁵,3λ⁵-diphosphete, 1 , reacts with GeCl₂ · 1,4-dioxane, SnCl₂, and (CO)₅W(Z-cyclooctene) to give the complexes {HCP[N(CH₃)₂]₂}₂ · GeCl₂, 3 , {HCP[N(CH₃)₂]₂}₂ · SnCl₂, 4 , and {HCP[N(CH₃)₂]₂}₂ · W(CO)₅, 5 , respectively. The n.m.r., mass, and i.r. spectra of the new compounds as well as the crystal and molecular structures of 3 and 4 are reported and the bonding situation in compounds 3–5 is discussed.     

(Dicarbonyl)(π-cyclohexadienyl)iron iodide,trichlorostannate, and tris(cymantrenecarboxylato)stannate: Synthesis and molecular structures

A reaction of [(η⁵-C₆H₇)Fe(CO)₃]BF₄ with KI in acetone gave brown crystals of the complex [(η⁵-C₆H₇)Fe(CO)₂]I (I), which was treated with SnCl₂ in THF to form orange crystals of the complex [(η⁵-C₆H₇)Fe(CO)₂]SnCl₃ (II). A reaction of complex II with potassium cymantrenecarboxylate ((CO)₃MnC₅H₄COOK, or CymCOOK) in THF yielded yellow crystals of the complex [(η⁵-C₆H₇)Fe(CO)₂]Sn(CymCOO)₃ (III). Structures I–III were identified using X-ray diffraction. The fragment (η⁵-C₆H₇)Fe(CO)₂ in complexes I–III remains virtually unchanged. The Fe-I bonds in complex I (2.6407(3) Å) and the Fe-Sn bonds in complexes II and III (2.4854(3) and 2.4787(4) Å, respectively) are appreciably shorter than the sum of the covalent radii of the corresponding elements, probably because of an additional dative interaction of the d electrons of iron with the vacant d orbitals of iodine or tin.     

Synthesis and reactivity of germyl complexes of manganese and rhenium

Trichlorogermyl complexes M(GeCl₃)(CO)_nP_{5? n} (1–4) [M = Mn, Re; n = 2, 3; P = PPh(OEt)₂ (a), P(OEt)₃ (b)] were prepared by allowing chloro compounds MCl(CO)_nP_{5? n} to react with an excess of GeCl₂?dioxane in 1,2-dichloroethane. Treatment of compounds 1–4 with LiAlH₄ in thf yielded trihydridegermyl derivatives M(GeH₃)(CO)_nP_5?n (5–8), whereas treatment of the same complexes with NaBH₄ in ethanol afforded triethoxygermyl derivatives M[Ge(OEt)₃](CO)_nP_5?n (9–11). Trimethylgermyl compounds M(GeMe₃)(CO)_nP_5?n (12, 13) and the alkynylgermyl derivative Mn[Ge(CCPh)₃](CO)₃[PPh(OEt)₂]₂ (14a) were also prepared by allowing trichlorogermyl compounds 1–4 to react with either MgBrMe or Li⁺CCPh^?, respectively, in thf. Treatment of compound Re(GeCl₃)(CO)₃[PPh(OEt)₂]₂ (4a) with SnCl₂?2H₂O gave the stannyl-germyl derivative Re[GeCl₂(SnCl₃)](CO)₃[PPh(OEt)₂]₂ (15a). The complexes were characterised by spectroscopy and X-ray crystal structure determination of 4a, 5a, and 13a.     

Synthesis and reactivity of germyl complexes of manganese and rhenium

Trichlorogermyl complexes M(GeCl₃)(CO)_nP_{5− n} (1–4) [M = Mn, Re; n = 2, 3; P = PPh(OEt)₂ (a), P(OEt)₃ (b)] were prepared by allowing chloro compounds MCl(CO)_nP_{5− n} to react with an excess of GeCl₂•dioxane in 1,2-dichloroethane. Treatment of compounds 1–4 with LiAlH₄ in thf yielded trihydridegermyl derivatives M(GeH₃)(CO)_nP_5−n (5–8), whereas treatment of the same complexes with NaBH₄ in ethanol afforded triethoxygermyl derivatives M[Ge(OEt)₃](CO)_nP_5−n (9–11). Trimethylgermyl compounds M(GeMe₃)(CO)_nP_5−n (12, 13) and the alkynylgermyl derivative Mn[Ge(CCPh)₃](CO)₃[PPh(OEt)₂]₂ (14a) were also prepared by allowing trichlorogermyl compounds 1–4 to react with either MgBrMe or Li⁺CCPh⁻, respectively, in thf. Treatment of compound Re(GeCl₃)(CO)₃[PPh(OEt)₂]₂ (4a) with SnCl₂•2H₂O gave the stannyl-germyl derivative Re[GeCl₂(SnCl₃)](CO)₃[PPh(OEt)₂]₂ (15a). The complexes were characterised by spectroscopy and X-ray crystal structure determination of 4a, 5a, and 13a.     

Syntheses,characterizations, and crystal structures of organotin(IV) chloride complexes with 4,4′‐bipyridine

The organotin(IV) chlorides R_nSnCl_4−n (n = 3, R = Ph, PhCH₂, n−Bu; and n =2, R = n−Bu, Ph, PhCH₂) react with 4,4′‐bipyridine (4′4‐bpy) to give [(Ph₃SnCl)₂(4,4′‐bpy)_1.5(C₆H₆)_0.5] ( 1 ), [(PhCH₂)₃‐ SnCl]₂ (4,4′‐bpy) ( 2 ), [(n−Bu)₃SnCl]₂(4,4′‐bpy) ( 3 ), [(n−Bu)₂SnCl₂(4,4′‐bpy)] ( 4 ), [Ph₂SnCl₂(4,4′‐bpy)] ( 5 ), and [(PhCH₂)₂SnCl₂(4,4′‐bpy)] ( 6 ). The new complexes have been characterized by elemental analyses, IR, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopy. The structures of ( 1 ), ( 2 ), ( 4 ), and ( 6 ) have been determined by X‐ray crystallography. Crystal structures of ( 1 ) and ( 2 ) show that the coordination number of tin is five. In complex ( 1 ), two different molecules exist: one is a binuclear molecule bridged by 4,4′‐bpy and another is a mononuclear one, only one N of 4,4′‐bpy coordinate to tin. Complex ( 2 ) contains an infinite 1‐D polymeric binuclear chain by weak Sn…Cl intermolecular interactions with neighboring molecules. In the complexes ( 4 ) and ( 6 ), the tin is six‐coordinate, and the 4,4′‐bpy moieties bridge adjacent dialkyltin(IV)dichloride molecules to form a linear chain. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:338–346, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20016     

Novel organotin antibacterial and anticancer drugs

From the reaction of 6-(p-methoxyphenyl) fulvene (1a), 6-(p-N,N-dimethylaminophenyl) fulvene (1b) and 6-(3,4-dimethoxyphenyl) fulvene (1c) with LiBEt₃H, lithiated cyclopentadienide intermediates (2a–c) were synthesised. These intermediates were then transmetallated to tin with SnCl₄ to yield tetra-substituted bis(cyclopentadienyl)tin dichloride complexes (3a–c). Further reaction with tin tetrachloride yielded the benzyl-substituted derivatives bis-[(p-methoxybenzyl)cyclopentadienyl] tin(IV) dichloride (4a), bis-[(p-N,N-dimethylaminobenzyl)cyclopentadienyl] tin(IV) dichloride (4b), and bis-[(3,4-dimethoxyphenyl)cyclopentadienyl] tin(IV) dichloride (4c). Preliminary antibacterial tests were carried out using the Kirby–Bauer disk-diffusion method, in which 4a–c showed little to no activity against the Gram-negative bacterium Escherichia coli, but medium activity against Gram-positive bacteria (MRSA, MSSA). In addition, the organotin complexes had their cytotoxicity investigated through preliminary in vitro testing on the LLC-PK (pig kidney epithelial) cell line in order to determine their IC50 values. Compound 4c showed no cytotoxic activity, while 4a and 4b were found to have IC50 values of 15 and 205 μM, respectively.     

Crystal structure of germanium(II) dichloride solvated by tetrahydrofuran

The thermally highly unstable tetrahydrofuran solvate of germanium(II) dichloride (GeCl₂ · 2THF) was crystallized, and its crystal structure was determined. It consists of a chain of GeCl₂ units connected by secondary Cl···Ge contacts [3.846(2) Å] in which each Ge atom is coordinated to two molecules of THF. Two weak hydrogen bonds of the C H ··· Cl Ge type in GeCl₂ · 2THF were also detected both with lengths of 2.90(3) Å. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:361–363, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20105     

Rhodium(I) indazole and indazolate complexes

The preparation of cationic indazole (HIdz) rhodium(I) complexes of the types [(diolefin)Rh(HIdz)₂]ClO₄ and [(CO)₂Rh(HIdz)₂]ClO₄ is described. Neutral binuclear rhodium(I) complexes of the type [Y₂Rh(μ-Idz)]₂ (Y₂  COD, TFB, NBD, (CO)₂ or (CO)(PPh₃)) are obtained by treating the corresponding complexes [Y₂RhCl]₂ with indazole and organic or inorganic bases. The cationic mononuclear derivatives react with the solvated species [Y₂Rh(acetone)_x]ClO₄ in the presence of triethylamine to give neutral binuclear complexes of the types [(CO)₂Rh(μ-Idz)₂Rh(diolefin)], [(Ph₃P)(CO)Rh(μ-Idz)₂Rh(diolefin)] and [(diolefin)Rh(μ-Idz)Rh(diolefin′)] (diolefin  COD, TFB or NBD; diolefin′  COD or TFB). Alternative methods for the synthesis of the binuclear complexes are also described.     

Complexes dinucleaires pontes des metaux d8: II.preparation de deux series de composes du rhodium(I) pentacoordonne

In the course of the study of the reactivity of the dinuclear complexes [RhCl(CO)(C₂H₂)]₂ and [RhSR(CO)₂]₂ towards nucleophiles, two series of dinuclear pentacoordinated rhodium(I) complexes, [RhCl(CO)(C₂H₄)(amine)]₂ and [RhSR(CO)₂PR₃]₂, have been isolated.     

Heterobimetallic Re–Pd,Re–Au and Re–Cu complexes derived from diphenylphosphino cyrhetrene: Synthesis and X-ray structure

Diphenylphosphinecyrhetrene ligand (η⁵-C₅H₄PPh₂)Re(CO)₃ (1) reacts with 1 equiv. of PdCl₂(NCPh)₂ to form, after workup, the square-planar trans-[(η⁵-C₅H₄PPh₂)Re(CO)₃]PdCl₂(NCMe) (2). Similarly, reaction of 1 with (tetrahydrothiophene)AuCl produces, in excellent yield, the bimetallic complex [(η⁵-C₅H₄PPh₂)Re(CO)₃]AuCl (3) with a linear P–Au–Cl moiety. From the reaction of 2 equiv. of 1 with CuBr(SMe₂) the planar-trigonal complex [(η⁵-C₅H₄PPh₂)Re(CO)₃]₂CuBr (4) was obtained. ³¹P NMR and X-ray crystallography demonstrate, for the three cases, that (η⁵-C₅H₄PPh₂)Re(CO)₃ acts as a monodentate ligand. The structural parameters of the bimetallic complexes are compared with related diphenylphosphinoferrocene metal complexes, described in the literature.     

SnCl2 als Brückenligand in [{(CO)5M}2Sn(Cl)2]2− (M = Cr,Mo, W) — Synthese,Struktur und Reaktivität

SnCl₂ as a Bridging Ligand in [{(CO)₅M}₂Sn(Cl)₂]^2? (M = Cr, Mo, W) — Synthesis, Structure, and Reactivity [{(CO)₅Cr}₂Sn(Cl)₂]^2?, 1 , may be obtained from [(CO)₅Cr]^2? or [(CO)₅CrSnCl₂ · THF] in fair yields. Alternatively, 1 is accessible by the reaction of [Cr₂(CO)₁₀]^2? with SnCl₂. This procedure may be extended to the synthesis of [{(CO)₅M}₂Sn(Cl)₂]^2? (M = Mo, 2 ; M = W, 3 ). The compounds 1–3 are crystallized as their alkalimetal (12-crown-4)₂ or [2,2,2]cryptand salts. X-ray analyses demonstrate bridging SnCl₂-moieties with M? Sn? M-angles close to 130° in each case. The relation of the bonding situation in 1–3 to the ones observed for stannylene or ?inidene”? complexes, respectively, is discussed. The transformation of 1 into the rhombododecahedral (X-ray analysis) Sn? O-cage compound [{(CO)₅CrSn}₆(μ₃-O)₄(μ₃-OH)₄], 4 , demonstrates the reactivity of the dianions 1–3 .