Highly Strained Heterometallacycles of Group 4 Metallocenes with Bis(diphenylphosphino)methanide Ligands

A study of the coordination chemistry of different bis(diphenylphosphino)methanide ligands [Ph₂PC(X)PPh₂] (X=H, SiMe₃) with Group 4 metallocenes is presented. The paramagnetic complexes [Cp₂Ti{κ²‐P,P‐Ph₂PC(X)PPh₂}] (X=H ( 3 a ), X=SiMe₃ ( 3 b )) have been prepared by the reactions of [(Cp₂TiCl)₂] with [Li{C(X)PPh₂}₂(thf)₃]. Complex 3 b could also be synthesized by reaction of the known titanocene alkyne complex [Cp₂Ti(η²‐Me₃SiC₂SiMe₃)] with Ph₂PC(H)(SiMe₃)PPh₂ ( 2 b ). The heterometallacyclic complex [Cp₂Zr(H){κ²‐P,P‐Ph₂PC(H)PPh₂}] ( 4 aH ) has been prepared by reaction of the Schwartz reagent with [Li{C(H)PPh₂}₂(thf)₃]. Reactions of [Cp₂HfCl₂] with [Li{C(X)PPh₂}₂(thf)₃] gave the highly strained corresponding metallacycles [Cp₂M(Cl){κ²‐P,P‐Ph₂PC(X)PPh₂}] ( 5 aCl and 5 bCl ) in very good yields. Complexes 3 a , 4 aH , and 5 aCl have been characterized by X‐ray crystallography. Complex 3 a has also been characterized by EPR spectroscopy. The structure and bonding of the complexes has been investigated by DFT analysis. Reactions of complexes 4 aH , 5 aCl , and 5 bCl did not give the corresponding more unsaturated heterometallacyclobuta‐2,3‐dienes.     

Metal Derivatives of Heterocyclic Thioamides: Synthesis and Crystal Structures of Copper Complexes with 1‐Methyl‐1,3‐imidazoline‐2‐thione and 1,3‐Imidazoline‐2‐thione

Reactions of copper(I) halides (Cl, Br, I) with 1‐methyl‐1, 3‐imidazoline‐2‐thione (mimzSH) in 1 : 2 molar ratio yielded sulfur‐bridged dinuclear [Cu₂X₂(μ‐S‐mimzSH)₂(η¹‐S‐mimzSH)₂] (X = I, 1 , Br, 2 ; Cl, 3 ) complexes. Copper(I) iodide with 1,3‐imidazoline‐2‐thione (imzSH₂) and Ph₃P in 1 : 1 : 1 molar ratio has also formed a sulfur‐bridged dinuclear [Cu₂I₂(μ‐S‐imzSH₂)₂(PPh₃)₂] ( 4 ) complex. The central Cu(μ‐S)₂Cu cores form parallelograms with unequal Cu–S bond distances {2.324(2), 2.454(3) Å} ( 1 ); {2.3118(6), 2.5098(6) Å} ( 2 ); {2.3075(4), 2.5218(4) Å} ( 3 ); {2.3711(8), 2.4473(8) Å} ( 4 ). The Cu···Cu separations, 2.759–2.877Å in complexes 1 – 3 are much shorter than 3.3446Å in complex 4 . The weak intermolecular interactions {H₂CH···S^# ( 2 ); CH···Cl^# ( 3 ); NH···I^# ( 4 )} between dimeric units in complexes 2 – 4 lead to the formation of linear 1D polymers.     

Remote Multiproton Storage within a Pyrrolide‐Pincer‐Type Ligand

A chemically non‐innocent pyrrole‐based trianionic (ONO)^3? pincer ligand within [(pyr‐ONO)TiCl(thf)₂] ( 2 ) can access the dianionic [(3H‐pyr‐ONO)TiCl₂(thf)] ( 1‐THF ) and monoanionic [(3H,4H‐pyr‐ONO)TiCl₂(OEt₂)][B{3,5‐(CF₃)₂C₆H₃}₄] ( 3‐Et₂O ) states through remote protonation of the pyrrole γ‐C π‐bonds. The homoleptic [(3H‐pyr‐ONO)₂Zr] ( 4 ) was synthesized and characterized by X‐ray diffraction and NMR spectroscopy in solution. The protonation of 4 by [H(OEt₂)₂][B{C₆H₃(CF₃)₂}₄] yields [(3H,4H‐pyr‐ONO)(3H‐pyr‐ONO)Zr][B{3,5‐(CF₃)₂C₆H₃}₄] ( 5 ), thus demonstrating the storage of three protons.     

Cobalt(II) Complexes with N‐Thioacylamidophosphates and 2,2′‐Bipyridyl and 1,10‐Phenathroline. Crystal Structures,Solution 1H NMR Spectral and Magnetic Properties

Structure and magnetic properties of N‐diisopropoxyphosphorylthiobenzamide PhC(S)‐N(H)‐P(O)(OiPr)₂ ( HL^I ) and N‐diisopropoxyphosphoryl‐N′‐phenylthiocarbamide PhN(H)‐C(S)‐N(H)‐P(O)(OiPr)₂ ( HL^II ) complexes with the Co^II cation of formulas [Co{PhC(S)‐N‐P(O)(OiPr)₂}₂] ( 1 ), [Co{PhN(H)‐C(S)‐N‐P(O)(OiPr)₂}₂] ( 2 ), [Co{PhC(S)‐N(H)‐P(O)(OiPr)₂}₂{PhC(S)‐N‐P(O)(OiPr)₂}₂] ( 1a ) and [Co{PhC(S)‐N‐P(O)(OiPr)₂}₂}(2,2′‐bipy)] ( 3 ), [Co{PhC(S)‐N‐P(O)(OiPr)₂}₂(1,10‐phen)] ( 4 ), [Co{PhN(H)‐C(S)‐N‐P(O)(OiPr)₂}₂(2,2′‐bipy)] ( 5 ), [Co{PhN(H)‐C(S)‐N‐P(O)(OiPr)₂}₂(1,10‐phen)] ( 6 ) were investigated. Paramagnetic shifts in the ¹H NMR spectrum were observed for high‐spin Co^II complexes with HL^I,II , incorporating the S‐C‐N‐P‐O chelate moiety and two aromatic chelate ligands. Investigation of the thermal dependence of the magnetic susceptibility has shown that the extended materials 1‐2 and 6 show ferromagnetic exchange between distorted tetrahedral ( 1 , 2 ) or octahedral ( 1a , 6 ) metal atoms whereas 3 and 5 show antiferromagnetic properties. Compound 4 behaves as a spin‐canted ferromagnet, an antiferromagnetic ordering taking place below a critical temperature, T_c = 115 K. Complexes 1 and 1a were investigated by single crystal X‐ray diffraction. The cobalt(II) atom in complex 1 resides a distorted tetrahedral O₂S₂ environment formed by the C=S sulfur atoms and the P=O oxygen atoms of two deprotonated ligands. Complex 1a has a tetragonal‐bipyramidal structure, Co(O^ax)₂(O^eq)₂(S^eq)₂, and two neutral ligand molecules are coordinated in the axial positions through the oxygen atoms of the P=O groups. The base of the bipyramid is formed by two anionic ligands in the typical 1,5‐O,S coordination mode. The ligands are in a trans configuration.     

Cerium(III/IV) Formamidinate Chemistry,and a Stable Cerium(IV) Diolate

Four new cerium(III) formamidinate complexes comprising [Ce(p‐TolForm)₃], [Ce(DFForm)₃(thf)₂], [Ce(DFForm)₃], and [Ce(EtForm)₃] were synthesized by protonolysis reactions using [Ce{N(SiMe₃)₂}₃] and formamidines of varying functionality, namely N,N′‐bis(4‐methylphenyl)formamidine (p‐TolFormH), N,N′‐bis(2,6‐difluorophenyl)formamidine (DFFormH), and the sterically more demanding N,N′‐bis(2,6‐diethylphenyl)formamidine (EtFormH). The bimetallic cerium lithium complex [LiCe(DFForm)₄] was synthesized by treating a mixture of [Ce{N(SiHMe₂)₂}₃(thf)₂] and [Li{N(SiHMe₂)₂}] with four equivalents of DFFormH in toluene. Oxidation of the trivalent cerium(III) formamidinate complexes by trityl chloride (Ph₃CCl) caused dramatic color changes, although the cerium(IV) species appeared transient and reformed cerium(III) complexes and N′‐trityl‐N,N′‐diarylformamidines shortly after oxidation. The first structurally characterized homoleptic cerium(IV) formamidinate complex [Ce(p‐TolForm)₄] was obtained through a protonolysis reaction between [Ce{N(SiHMe₂)₂}₄] and four equivalents of p‐TolFormH. [Ce{N(SiHMe₂)₂}₄] was also treated with DFFormH and EtFormH, but the resulting cerium(IV) complexes decomposed before isolation was possible. The new cerium(IV) silylamide complex [Ce{N(SiMe₃)₂}₃(bda)_0.5]₂ (bda=1,4‐benzenediolato) was synthesized by treatment of [Ce{N(SiMe₃)₂}₃] with half an equivalent of 1,4‐benzoquinone, and showed remarkable resistance towards protonolysis or reduction.     

Transformations of P-chalcogenide precursors with a hydrated metal salt

The preparation, characterisation and X-ray structures of the three Ni(II) salts [Ni{ArP(OH)S₂}₂(thf)₂] (1) (Ar = 4-anisyl), [Ni{PhP(OH)Se₂}₂(thf)₂] (2) and [Ni{P(OH)₂S₂}₂(thf)₄] (3) are reported.     

Oxorhenium(V) Complexes with 1,3,4‐Triphenyl‐1,2,4‐triazol‐5‐ylidene

Reactions of the oxorhenium(V) complexes [ReOX₃(PPh₃)₂] (X = Cl, Br) with the N‐heterocyclic carbene (NHC) 1,3,4‐triphenyl‐1,2,4‐triazol‐5‐ylidene (L^Ph) under mild conditions and in the presence of MeOH or water give [ReOX₂(Y)(PPh₃)(L^Ph)] complexes (X = Cl, Br; Y = OMe, OH). Attempted reactions of the carbene precursor 5‐methoxy‐1,3,4‐triphenyl‐4,5‐dihydro‐1H‐1,2,4‐triazole ( 1 ) with [ReOCl₃(PPh₃)₂] or [NBu₄][ReOCl₄] in boiling xylene resulted in protonation of the intermediately formed carbene and decomposition products such as [HL^Ph][ReOCl₄(OPPh₃)], [HL^Ph][ReOCl₄(OH₂)] or [HL^Ph][ReO₄] were isolated. The neutral [ReOX₂(Y)(PPh₃)(HL^Ph)] complexes are purple, airstable solids. The bulky NHC ligands coordinate monodentate and in cis‐position to PPh₃. The relatively long Re–C bond lengths of approximate 2.1Å indicate metal‐carbon single bonds.     

Synthesis and characterization of silver(I) complexes with N‐thiophosphorylated thiobenzamide or thiourea and phosphines

A reaction of the potassium salts of RC(S)NHP(S)(OiPr)₂ (R = PhNH, HL ^I; Ph, HL ^II) with a mixture of AgNO₃ and Ph₂P(CH₂)_{1 − 3}PPh₂ or Ph₂P(C₅H₄FeC₅H₄)PPh₂ in aqueous EtOH/CH₂Cl₂ leads to [Ag₂(Ph₂PCH₂PPh₂)₂L^INO₃] ( 1 ), [Ag{Ph₂P (CH₂)₂PPh₂}L^I,II] ( 2, 6 ), [Ag{Ph₂P(CH₂)₃PPh₂}L^I,II] ( 3, 7 ), [Ag{Ph₂P(C₅H₄FeC₅H₄)PPh₂}L^I,II] ( 4, 8 ), and [Ag₂(Ph₂PCH₂PPh₂)L^II₂] ( 5 ) complexes. The structures of these compounds were investigated by ¹H and ³¹P{¹H} NMR spectroscopy and elemental analyses. It was established that the binuclear complexes 1 and 5 are luminescent in the solid state at ambient conditions. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:386–391, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20627     

The Nature of the UC Double Bond: Pushing the Stability of High‐Oxidation‐State Uranium Carbenes to the Limit

Treatment of [K(BIPM^MesH)] (BIPM^Mes={C(PPh₂NMes)₂}^2?; Mes=C₆H₂‐2,4,6‐Me₃) with [UCl₄(thf)₃] (1 equiv) afforded [U(BIPM^MesH)(Cl)₃(thf)] ( 1 ), which generated [U(BIPM^Mes)(Cl)₂(thf)₂] ( 2 ), following treatment with benzyl potassium. Attempts to oxidise 2 resulted in intractable mixtures, ligand scrambling to give [U(BIPM^Mes)₂] or the formation of [U(BIPM^MesH)(O)₂(Cl)(thf)] ( 3 ). The complex [U(BIPM^Dipp)(μ‐Cl)₄(Li)₂(OEt₂)(tmeda)] ( 4 ) (BIPM^Dipp={C(PPh₂NDipp)₂}^2?; Dipp=C₆H₃‐2,6‐iPr₂; tmeda=N,N,N′,N′‐tetramethylethylenediamine) was prepared from [Li₂(BIPM^Dipp)(tmeda)] and [UCl₄(thf)₃] and, following reflux in toluene, could be isolated as [U(BIPM^Dipp)(Cl)₂(thf)₂] ( 5 ). Treatment of 4 with iodine (0.5 equiv) afforded [U(BIPM^Dipp)(Cl)₂(μ‐Cl)₂(Li)(thf)₂] ( 6 ). Complex 6 resists oxidation, and treating 4 or 5 with N‐oxides gives [{U(BIPM^DippH)(O)₂‐ (μ‐Cl)₂Li(tmeda)] ( 7 ) and [{U(BIPM^DippH)(O)₂(μ‐Cl)}₂] ( 8 ). Treatment of 4 with tBuOLi (3 equiv) and I₂ (1 equiv) gives [U(BIPM^Dipp)(OtBu)₃(I)] ( 9 ), which represents an exceptionally rare example of a crystallographically authenticated uranium(VI)–carbon σ bond. Although 9 appears sterically saturated, it decomposes over time to give [U(BIPM^Dipp)(OtBu)₃]. Complex 4 reacts with PhCOtBu and Ph₂CO to form [U(BIPM^Dipp)(μ‐Cl)₄(Li)₂(tmeda)(OCPhtBu)] ( 10 ) and [U(BIPM^Dipp)(Cl)(μ‐Cl)₂(Li)(tmeda)(OCPh₂)] ( 11 ). In contrast, complex 5 does not react with PhCOtBu and Ph₂CO, which we attribute to steric blocking. However, complexes 5 and 6 react with PhCHO to afford (DippNPPh₂)₂C?C(H)Ph ( 12 ). Complex 9 does not react with PhCOtBu, Ph₂CO or PhCHO; this is attributed to steric blocking. Theoretical calculations have enabled a qualitative bracketing of the extent of covalency in early‐metal carbenes as a function of metal, oxidation state and the number of phosphanyl substituents, revealing modest covalent contributions to U?C double bonds.     

Transition‐Metal‐Mediated Cleavage of Fluoro‐Silanes under Mild Conditions

Si?F bond cleavage of fluoro‐silanes was achieved by transition‐metal complexes under mild and neutral conditions. The Iridium‐hydride complex [Ir(H)(CO)(PPh₃)₃] was found to readily break the Si?F bond of the diphosphine‐ difluorosilane {(o‐Ph₂P)C₆H₄}₂Si(F)₂ to afford a silyl complex [{[o‐(iPh₂P)C₆H₄]₂(F)Si}Ir(CO)(PPh₃)] and HF. Density functional theory calculations disclose a reaction mechanism in which a hypervalent silicon species with a dative Ir→Si interaction plays a crucial role. The Ir→Si interaction changes the character of the H on the Ir from hydridic to protic, and makes the F on Si more anionic, leading to the formation of H^δ+???F^δ? interaction. Then the Si?F and Ir?H bonds are readily broken to afford the silyl complex and HF through σ‐bond metathesis. Furthermore, the analogous rhodium complex [Rh(H)(CO)(PPh₃)₃] was found to promote the cleavage of the Si?F bond of the triphosphine‐monofluorosilane {(o‐Ph₂P)C₆H₄}₃Si(F) even at ambient temperature.     

Synthesis and Characterization of trans‐PdII Trimethylsilylchalcogenolates

The trans‐bis(trimethylsilyl)chalcogenolate palladium complexes, trans‐[Pd(ESiMe₃)₂(PnBu₃)₂] [E = S ( 1 ) and Se ( 2 )] were synthesized in good yields and high purity by reacting trans‐[PdCl₂(PBu₃)₂] with LiESiMe₃ (E = S, Se), respectively. These complexes were characterized by ¹H, ¹³C{¹H}, ³¹P{¹H} (and ⁷⁷Se{¹H}) NMR spectroscopy and single‐crystal X‐ray analysis. The reaction of 2 with propionyl chloride led to the formation of trans‐[Pd(SeC(O)CH₂CH₃)₂(PnBu₃)₂] ( 3 ), a trans‐bis(selenocarboxylato) palladium complex and thus established a new method for the formation of this type of complex. Complex 3 was characterized by ¹H, ¹³C{¹H}, ³¹P{¹H} and ⁷⁷Se{¹H} NMR spectroscopy and a single‐crystal X‐ray structure analysis.     

Thiosemicarbazonates of Ruthenium(II): Crystal Structures of [Bis(triphenylphosphine)][bis(N‐phenyl‐pyridine‐2‐carbaldehyde Thiosemicarbazonato)]ruthenium(II) and [Bis(diphenylphosphino)butane][bis(salicylaldehyde Thiosemicarbazonato)]ruthenium(II)

Reaction of RuCl₂(PPh₃)₃ with N‐Phenyl‐pyridine‐2‐carbaldehyde thiosemicarbazone (C₅H₄N–C²(H)=N³‐N²H–C¹(=S)N¹HC₆H₅, Hpytsc‐NPh) in presence of Et₃N base led to loss of ‐N²H‐proton and yielded the complex [Ru(pytsc‐NPh)₂(Ph₃P)₂] ( 1 ). Similar reactions of precursor RuCl₂[(p‐tolyl)₃P]₃ with a series of thiosemicarbazone ligands, viz. pyridine‐2‐carbaldehyde thiosemicarbazone (Hpytsc), salicylaldehyde thiosemicarbazone (H₂stsc), and benzaldehyde thiosemicarbazone (Hbtsc), have yielded the complexes, [Ru(pytsc)₂{(p‐tolyl)₃P}₂] ( 2 ), [Ru(Hstsc)₂{(p‐tolyl)₃P}]₂ ( 3 ), and [Ru(btsc)₂{(p‐tolyl)₃P}₂] ( 4 ), respectively. The reactions of precursor Ru₂Cl₄(dppb)₃ {dppb = Ph₂P–(CH₂)₄–PPh₂} with H₂stsc, Hbtsc, furan‐2‐carbaldehyde thiosemicarbazone (Hftsc) and thiophene‐2‐carbaldehyde thiosemicarbazone (Httsc) have formed complexes of the composition, [Ru(Hstsc)₂(dppb)] ( 5 ), [Ru(btsc)₂(dppb)] ( 6 ), [Ru(ftsc)₂(dppb)] ( 7 ), and [Ru(ttsc)₂(dppb)] ( 8 ). The complexes have been characterized by analytical data, IR, NMR (¹H, ³¹P) spectroscopy and X‐ray crystallography ( 1 and 5 ). The proton NMR confirmed loss of –N²H– proton in all the compounds, and ³¹P NMR spectra reveal the presence of equivalent phosphorus atoms in the complexes. In all the compounds, thiosemicarbazone ligands coordinate to the Ru^II atom via hydrazinic nitrogen (N²) and sulfur atoms. The arrangement around each metal atom is distorted octahedral with cis:cis:trans P, P:N, N:S, S dispositions of donor atoms.     

Synthesen und Strukturen von Übergangsmetall‐Komplexen mit Dithiophosphinato‐ und Trithiophosphonato‐Liganden

Syntheses and Structures of Transition Metal Complexes with Dithiophosphinato and Trithiophosphinato Ligands The reactions of MnCl₂ with Ph₂P(S)(SSiMe₃) produced [Mn(S₂PPh₂)₂(thf)₂] ( 1 ) and [Mn(S₂PPh₂)₂(dme)] ( 2 ) (DME = 1,2‐Dimethoxyethane). The compounds [Co₆(S₃PPh)₂(μ⁴‐S)₂(μ³‐S)₂(PPh₃)₄] ( 3 ), [Co₂(S₃PPh)₂(PPh₃)₂] ( 4 ), [Ni(S₂PPh)(PPhEt₂)₂] ( 5 ), [Ni(S₃PPh)(PPhEt₂)₂] ( 6 ) and [Cu₄(S₃PPh)₂(dppp)₂] ( 8 ) [dppp = 1,3‐Bis(diphenylphosphanyl)propane] were obtained from reactions of first‐row transition metal halides with PhP(S)(SSiMe₃)₂ in the presence of tertiary phosphines. In a reaction of PhP(S)(SSiMe₃)₂ with PhPEt₂ PhPEt₂PS₂Ph ( 7 ) was isolated. All compounds were characterized by X‐ray crystallography.     

The in vitro antifungal activity of some dithiocarbamate organotin(IV) compounds on Candida albicans— a model for biological interaction of organotin complexes

The in vitro antifungal activity of the dithiocarbamate organotin complexes [Sn{S₂CN(CH₂)₄}₂Cl₂] ( 1 ), [Sn{S₂CN(CH₂)₄}₂Ph₂] ( 2 ), [Sn{S₂CN(CH₂)₄}Ph₃] ( 3 ), [Sn{S₂CN(CH₂)₄}₂n‐Bu₂] ( 4 ), [Sn{S₂CN(CH₂)₄}Cy₃] {Cy = cyclohexyl} ( 5 ), [Sn{S₂CN(C₂H₅)₂}₂Cl₂] ( 6 ), [Sn{S₂CN(C₂H₅)₂}₂Ph₂] ( 7 ), [Sn{S₂CN(C₂H₅)₂}Ph₃] ( 8 ), [Sn{S₂CN(C₂H₅)₂}₃Ph] ( 9 ) and [Sn{S₂CN(C₂H₅)₂}Cy₃] ( 10 ) has been screened against Candida albicans (ATCC 18804), Candida tropicalis (ATCC 750) and resistant Candida albicans collected from HIV‐positive Brazilian patients with oral candidiasis. All compounds exhibited antifungal activities and complexes 3 and 8 displayed the best results. We have investigated the effect of compounds 1–10 on the cellular activity of the yeast cultures. Changes in mitochondrial function have not been detected. However, all drugs reduced ergosterol biosynthesis. Preliminary studies on DNA integrity indicated that the compounds do not cause gross damage to yeast DNA. The data suggest that these compounds share some mechanisms of action on cell membranes similar to that of polyene but not with azole drugs, normally used in Candida infections. Copyright © 2008 John Wiley & Sons, Ltd.     

Chloridobis[2‐(diphenylphosphanyl)ethanamine‐κ2P,N](triphenylphosphane‐κP)ruthenium(II) chloride toluene monosolvate

The aminophosphane ligand 1‐amino‐2‐(diphenylphosphanyl)ethane [Ph₂P(CH₂)₂NH₂] reacts with dichloridotris(triphenylphosphane)ruthenium(II), [RuCl₂(PPh₃)₃], to form chloridobis[2‐(diphenylphosphanyl)ethanamine‐κ²P,N](triphenylphosphane‐κP)ruthenium(II) chloride toluene monosolvate, [RuCl(C₁₈H₁₅P)(C₁₄H₁₆NP)₂]Cl·C₇H₈ or [RuCl(PPh₃){Ph₂P(CH₂)₂NH₂}₂]Cl·C₇H₈. The asymmetric unit of the monoclinic unit cell contains two molecules of the Ru^II cation, two chloride anions and two toluene molecules. The Ru^II cation is octahedrally coordinated by two chelating Ph₂P(CH₂)₂NH₂ ligands, a triphenylphosphane (PPh₃) ligand and a chloride ligand. The three P atoms are meridionally coordinated, with the Ph₂P– groups from the ligands being trans. The two –NH₂ groups are cis, as are the chloride and PPh₃ ligands. This chiral stereochemistry of the [RuCl(PPh₃){Ph₂P(CH₂)₂NH₂}₂]⁺ cation is unique in ruthenium–aminophosphane chemistry.     

Attempted Reduction of Divalent Rare Earth Iodo Aminopyridinates

Rare examples of amido‐iodo complexes of selected divalent lanthanides can be synthesized by using deprotonated Ap*H {Ap*H = 2,6‐diisopropylphenyl)‐[6‐(2,4,6‐triisopropylphenyl)‐pyridin‐2‐yl]‐amine} as a stabilizing ligand. Reaction of [Ap*K]_n with [LnI₂(thf)_n] (Ln = Eu, Yb, n = 4,5) in THF leads to [Ln(Ap*)I(thf)₂]₂ (Ln = Eu, Yb). An attempted reduction of these divalent heteroleptic complexes with KC₈ to synthesize complexes containing an unsupported Ln–Ln bond resulted in the formation of [Ln(Ap*)₂(thf)₂]. These lanthanide complexes were characterized by X‐ray structure analysis.     

Untersuchungen zur Darstellung von [CpxSb{M(CO)5}2] (Cpx = Cp,Cp*; M = Cr,W)

Investigations of the Synthesis of [Cp^xSb{M(CO)₅}₂] (Cp^x = Cp, Cp*; M = Cr, W) The reaction of CpSbCl₂ with [Na₂{Cr₂(CO)₁₀}] leads to the chlorostibinidene complex [ClSb{Cr(CO)₅}₂(thf)] ( 1 ), whereas the reaction of CpSbCl₂ with [Na₂{W₂(CO)₁₀}] results in the formation of the complexes [ClSb{W(CO)₅}₃] ( 2 ), [Na(thf)][Cl₂Sb{W(CO)₅}₂] ( 3 ), [ClSb{W(CO)₅}₂(thf)] ( 4 ) and [Sb₂{W(CO)₅}₃] ( 5 ). The stibinidene complex [CpSb{Cr(CO)₅}₂] ( 6 ) is obtained by the reaction of [ClSb{Cr(CO)₅}₂] with NaCp, while its Cp* analogue [Cp*Sb{Cr(CO)₅}₂] ( 7 ) is formed via the metathesis of Cp*SbCl₂ with [Na₂{Cr₂(CO)₁₀}]. The products 2 , 3 , 4 and 7 are additionally characterised by X‐ray structure analyses.     

Magnetic Coupling between Metal Spins through the 7,7,8,8‐Tetracyanoquinodimethane (TCNQ) Dianion

A family of magnetic metal–organic frameworks, (Ph₃PMe)₂[M₂(TCNQ)₃] {M=Fe²⁺, Co²⁺, Ni²⁺ and Zn²⁺} have been prepared and structurally characterized. The honeycomb‐like “layers” consist of M^II ions doubly bridged with dinitrilomethane moieties of two 7,7,8,8‐tetracyanoquinodimethane (TCNQ) dianions which are further connected through phenyl rings to form a 3D dianionic framework [M₂TCNQ₃]^2? with Ph₃PMe⁺ cations filling cavities that run along the c axis. Studies of the magnetic coupling through the TCNQ dianion in these structures revealed that it can promote long‐range magnetic ordering despite the long coupling pathway.     

Synthesis and structural properties of a series of pentacoordinate rhodium nitrosyl complexes: Crystal and molecular structures of cis-dibromonitrosylbis(methoxydiphenylphosphine)rhodium and trans-dibromonitrosylbis(iso-propoxydiphenylphosphine)rhodium

The pentacoordinate rhodium nitrosyl complexes [RhBr₂(NO)L₂ [L = P(OPh)₂Ph, P(OMe)Ph₂ or P(OPrⁱ)Ph₂] have been synthesized and the structures of [RhBr₂(NO){P(OMe)Ph₂}₂] and [RhBr₂(NO){P(OPrⁱ)Ph₂}₂] have been determined X-ray crystallographically. Both of these latter compounds are tetragonal pyramidal with the nitrosyl group apical. The methoxydiphenylphosphine ligands in [RhBr₂(NO){P(OMe)Ph₂}₂] are cis-disposed whereas the larger cis-propoxydiphenylphosphine ligands in [RhBr₂(NO){P(OPrⁱ)Ph₂}₂] are mutually trans. The nitrosyl group in trans-[RhBr₂(NO){P(OPrⁱ)Ph₂}₂] eclipses an Rh-P axis but in cis-[RhBr₂(NO){P(OMe)Ph₂}₂] it is staggered with respect to the P-Rh-P linkage. The isomeric behaviour of nitrosyl complexes of type [RhX₂(NO)L₂] (X = halogen, L = phosphorus donor ligand) is rationalized in terms of the size of the ligand L.     

The Synthesis,Characterisation, and Reactivity of Some Polydentate Phosphinoamine Ligands with Benzene‐1,3‐diyl and Pyridine‐2,6‐diyl Backbones

The polydentate phosphinoamines 1,3‐{(Ph₂P)₂N}₂C₆H₄ and 2,6‐{(Ph₂P)₂N}₂C₅H₃N have been prepared in a single step from the reaction of the amines 1,3‐(NH₂)₂C₆H₄ or 2,6‐(NH₂)₂C₅H₃N with Ph₂PCl in presence of Et₃N (1 : 4 : 4 molar ratio) in CH₂Cl₂. Reaction of 1,3‐{(Ph₂P)₂N}₂C₆H₄ or 2,6‐{(Ph₂P)₂N}₂C₅H₃N with elemental sulfur or selenium in CH₂Cl₂ affords the corresponding tetrasulfide or tetraselenide, respectively, in good yield. The complexes [1,3‐{Mo(CO)₄(Ph₂P)₂N}₂(C₆H₄)] and [2,6‐{Mo(CO)₄(Ph₂P)₂N}₂(C₅H₃N)] were prepared from the reaction of these phosphinoamines with [Mo(CO)₄(nbd)] (nbd=norbornadiene) in toluene, and the structure of the latter complex has been determined by single‐crystal X‐ray diffraction analysis.