Zur Charakterisierung von 1,1,2,3,3-Pentacyanopropenid als Komplexligand in ein- und zweizähniger Funktion. Darstellung von Komplexen des Typs [MX(PPh3)n] (M = CuI,AgI; X = NCC{C(CN)2}2; n = 2, 3)

Pseudoelement Compounds. XII. [1] On the Characterization of 1,1,2,3,3-Pentacyanopropenide in Unidentate and Bidentate Function. Syntheses of Complexes of the Type [MX(PPh₃)_n] (M = Cu^I, Ag^I; X = NCC{C(CN)₂}₂; n = 2, 3) 1,1,2,3,3-Pentacyanopropenide is characterized as unidentate and bidentate ligand. For that reason compounds of the types [MX(PPh₃)₃] ( 6 ) and [MX(PPh₃)₂]₂ ( 8 ) (M = Cu^I, Ag^I) are synthesized. In the complexes 6 the ionic ligand is coordinated unidentately through an end-on nitrile group of a C(CN)₂ unit and in the dimeric complexes 8 bidentately bridging through the N atoms of a C(CN)₂ moiety too. The compounds are characterized by ¹³C NMR, ³¹P NMR and IR spectroscopy. The crystal structure of [AgX(PPh₃)₃] is presented and the structural parameters of the anion in this complex and in [CuX(PPh₃)₂]₂ [X = NCC{C(CN)₂}₂] are compared.     

Coordination behavior of chromone Schiff bases towards the [ReVO]3+ and [ReI(CO)3]+ cores

Herein, we describe the coordination behavior of chromone Schiff bases towards [Re^VO]³⁺ and [Re^I(CO)₃]⁺. The reaction between 2-(2-thiolphenyliminomethyl)-4H-chromen-4-one (Htch) and [Re(CO)₅Cl] led to fac-[Re(CO)₃(bsch)Cl] (1) (bsch = 2-benzothiazole-4H-chromen-4-one). The square pyramidal [ReO(Hns)] (2) {H₂ns=bis-[(2-phenylthiolate)iminomethyl]-methyl-1-(2-hydroxyphenyl)prop-2-en-1-one} and octahedral [ReO(OCH₃)(PPh₃)(Huch)] (3) complexes were isolated from reactions of trans-[Re^VOBr₃(PPh₃)₂] with Htch and H₃uch [(5Z)-5-((4-hydroxy-2-methoxy-2H-chromen-3-yl)methyleneamino)-6-amino-1,3-dimethylpyrimidine-2,4(1H, 3H)-dione], respectively. The chromone Schiff bases and their metal complexes were fully characterized via NMR-, IR- and UV–Vis spectroscopy, single crystal XRD analysis and conductivity measurements. In addition, DFT studies were conducted to compare selected optimized and experimental parameters of the complexes.     

Synthesis, structure, spectroscopic properties, electrochemistry, and DFT correlative studies of N-[(2-pyridyl)methyliden]-6-coumarin complexes of Cu(I) and Ag(I)

6-Aminocoumarin reacts with pyridine-2-carboxaldehyde and has synthesized N-[(2-pyridyl)methyliden]-6-coumarin (L). The ligand, L, reacts with [Cu(MeCN)₄]ClO₄/AgNO₃ to synthesize Cu(I) and Ag(I) complexes of formulae, [Cu(L)₂]ClO₄ and [Ag(L)₂]NO₃, respectively. While similar reaction in the presence of PPh₃ has isolated [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃. All these compounds are characterized by FTIR, UV-Vis and ¹H NMR spectroscopic data. In case of [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃, the structures have been confirmed by X-ray crystallography. The structure of the complexes are distorted tetrahedral in which L coordinates in a N,N′ bidentate fashion and other two coordination sites are occupied by PPh₃. The ligand and the complexes are fluorescent and the fluorescence quantum yields of [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃ are higher than [Cu(L)₂]ClO₄ and [Ag(L)₂]NO₃. Cu(I) complexes show Cu(II)/Cu(I) quasireversible redox couple while Ag(I) complexes exhibit deposition of Ag(0) on the electrode surface during cyclic voltammetric experiments. gaussian 03 computations of representative complexes have been used to determine the composition and energy of molecular levels. An attempt has been made to explain solution spectra and redox properties of the complexes.     

Preparation and Properties of trans-[CoCl2(tmd>)2]Cl,and trans- and cis-[Co(NCS)2(tmd)2]NO3 (tmd: Tetramethylenediamine)

The cobalt(III) complexes [CoX₂(tmd)₂]⁺ (X: Cl^? or NCS^?, tmd: tetramethylenediamine), in which tmd forms a seven-membered chelate ring, have been prepared. Trans-[CoCl₂(tmd)₂]Cl was derived from [Co(NO₂)₂(tmd)₂]NO₃ in a fairly good yield. Two geometrical isomers, trans and cis, of [Co(NCS)₂-(tmd)₂]NO₃ were independently synthesized from trans-[CoCl₂(tmd)₂]Cl by different methods. The geometrical configurations of the isomeric pair of the NCS complex have been determined based on chromatographic behavior, electronic absorption spectra, and vibrational spectra. The d-d and CT absorption maxima of the NCS complex (18.7 x 10³cm^?1 (ε = 275) and 30.9 x 10³cm^?1 (ε = 3630) for the trans isomer, 19.3 x 10³cm^?1 (ε = 302) and 31.0 x 10³cm^?1 (ε = 4070) for the cis isomer) and the Co-N(amine) stretching frequency of trans-[CoCl₂(tmd)₂]Cl (418 cm^?1) have been compared with those of the corresponding ethylenediamine and trimethylenediamine complexes.     

Diminished electron density in the Vaska‐type rhodium(I) complex trans‐[Rh(NCBH3)(CO)(PPh3)2]

Vaska‐type complexes, i.e. trans‐[RhX(CO)(PPh₃)₂] (X is a halogen or pseudohalogen), undergo a range of reactions and exhibit considerable catalytic activity. The electron density on the Rh^I atom in these complexes plays an important role in their reactivity. Many cyanotrihydridoborate (BH₃CN⁻) complexes of Group 6–8 transition metals have been synthesized and structurally characterized, an exception being the rhodium(I) complex. Carbonyl(cyanotrihydridoborato‐κN)bis(triphenylphosphine‐κP)rhodium(I), [Rh(NCBH₃)(CO)(C₁₈H₁₅P)₂], was prepared by the metathesis reaction of sodium cyanotrihydridoborate with trans‐[RhCl(CO)(PPh₃)₂], and was characterized by single‐crystal X‐ray diffraction analysis and IR, ¹H, ¹³C and ¹¹B NMR spectroscopy. The X‐ray diffraction data indicate that the cyanotrihydridoborate ligand coordinates to the Rh^I atom through the N atom in a trans position with respect to the carbonyl ligand; this was also confirmed by the IR and NMR data. The carbonyl stretching frequency ν(CO) and the carbonyl carbon ¹J_C–Rh and ¹J_C–P coupling constants of the C_ipso atoms of the triphenylphosphine groups reflect the diminished electron density on the central Rh^I atom compared to the parent trans‐[RhCl(CO)(PPh₃)₂] complex.     

Metal catalysed Brooke rearrangement of 3-Halo-1-(trimethylsilyl) propan-2-one (Halo = Cl or Br)

The complexes [IrH(CO)(PPh₃)₃], trans-[IrCI(CO)- (PPh₃)₂], [RhH(PPh₃)₄], [Pd(PPh₃)₄], [Pt(trans-stilbene)(PPh₃)₂] and [Pt(η³-CH₂-COCH₂)-(PPh₃)₂] catalyse the rearrangement of Me₃SiCH₂C(O)CH₂Cl to CH₂?C(OSiMe₃)-CH₂Cl.     

[Ni(NHC)2] as a Scaffold for Structurally Characterized trans [H−Ni−PR2] and trans [R2P−Ni−PR2] Complexes

The addition of PPh₂H, PPhMeH, PPhH₂, P(para-Tol)H₂, PMesH₂ and PH₃ to the two-coordinate Ni⁰ N-heterocyclic carbene species [Ni(NHC)₂] (NHC=IiPr₂, IMe₄, IEt₂Me₂) affords a series of mononuclear, terminal phosphido nickel complexes. Structural characterisation of nine of these compounds shows that they have unusual trans [H−Ni−PR₂] or novel trans [R₂P−Ni−PR₂] geometries. The bis-phosphido complexes are more accessible when smaller NHCs (IMe₄>IEt₂Me₂>IiPr₂) and phosphines are employed. P−P activation of the diphosphines R₂P−PR₂ (R₂=Ph₂, PhMe) provides an alternative route to some of the [Ni(NHC)₂(PR₂)₂] complexes. DFT calculations capture these trends with P−H bond activation proceeding from unconventional phosphine adducts in which the H substituent bridges the Ni−P bond. P−P bond activation from [Ni(NHC)₂(Ph₂P−PPh₂)] adducts proceeds with computed barriers below 10 kcal mol⁻¹. The ability of the [Ni(NHC)₂] moiety to afford isolable terminal phosphido products reflects the stability of the Ni−NHC bond that prevents ligand dissociation and onward reaction.     

Synthesis and characterization of platinum(II) complexes with 2-imidazolidinethione. X-ray crystal structure of tetra(2-imidazolidinethione- S )platinum(II) iodide dimethylsulfoxide solvate monohydrate

Preparations of trans-[PtX₂(Imt)₂] (Imt =?2-imidazolidinethione, X=Cl^? or I^?) and [Pt(Imt)₄]I₂ are described. These complexes were characterized by elemental analysis, thermal analysis, mid- and far-IR spectroscopy, and NMR (¹H and ¹³C) spectroscopy. The crystal and molecular structure of [Pt(Imt)₄]I₂ ·?DMSO ·?H₂O was determined by X-ray diffraction methods. The structural data reveal the following features: (a) the platinum atom in [Pt(Imt)₄]²⁺ is essentially in a square-planar environment, (b) the entire dication possesses approximately C _2h symmetry, (c) no appreciable hydrogen bonding exists between the iodide ions and the Imt ligands in the dication, (d) two pairs of two mutually cis Imt ligands are arranged above and below the PtS₄ plane, respectively, and (e) two planes defined by two trans Imt rings are perpendicular to each other.     

New organometallic Ru(II) and Fe(II) complexes with tetrathia-[7]-helicene derivative ligands

A series of organometallic complexes possessing new tetrathia-[7]-helicene nitrile derivative ligands [TH-7] as chromophores, of general formula [MCp(P–P)(NC{TH-[7]-Y}Z)][PF₆] (M = Ru, Fe, P–P = DPPE, Y = H, NO₂, Z = H, C≡N; M = Ru, L–L = 2PPh₃, Y = H, Z = H) has been synthesized and fully characterized. ¹H NMR, FT-IR and UV–Vis. spectroscopic data were analyzed with in order to evaluate the existence of electronic delocalization from the metal centre to the coordinated ligand to have some insight on the potentialities of these new compounds as non-linear optical molecular materials. Slow crystallization of compound [RuCp(PPh₃)₂(NC{TH-[7]-H}H)][PF₆] 2Ru revealed an interesting isomerization of the helical ligand with formation of two carbon-carbon bonds between the two terminal thiophenes, leading to the total closure of the helix (2*Ru).     

Ruthenium(II) carbonyl complexes with N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives and triphenylphosphine as effective catalysts for oxidation of alcohols

Ruthenium(II) complexes, [RuCl(L)(CO)(PPh₃)₂] {where L?=?N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives}, are prepared from reaction between [RuHCl(CO)(PPh₃)₃] and N-[di(alkyl/aryl)carbamothioyl]benzamide derivatives in toluene and characterized by elemental analysis and spectral data (electronic, infrared, ¹H NMR, and ³¹P NMR). The combination of [RuCl(L)(CO)(PPh₃)₂] (0.01?mmol) and N-methylmorpholine-N-oxide (NMO) (3?mmol) is an active catalyst for the oxidation of primary, secondary, cyclic, allylic, aliphatic, and benzylic alcohols to their corresponding aldehydes and ketones at room temperature. The oxidation protocol is simple to operate and gives the corresponding carbonyl compounds good to excellent yields.     

HPLC Method for the Determination of the Purity of K[Pt(NH3)Cl3], a Precursor of the Platinum Complexes with Cytostatic Activity

K[Pt(NH₃)Cl₃], a valuable precursor for the preparation of platinum complexes with cytostatic activity, e.g. satraplatin, picoplatin, LA-12 and cycloplatam, is currently prepared from cis-[Pt(NH₃)₂Cl₂] or K₂[PtCl₄] and these are the usual impurities in the final product. A simple, selective and sensitive HPLC-UV analytical method for the determination of the purity of K[Pt(NH₃)Cl₃] and the quantification of the impurities has been developed and validated. The platinum complexes present in the final product were separated on a strong base ion exchange column by the gradient elution with detection at 213 nm. Intra-assay precisions for the platinum complexes respective to their ions ([PtCl₄]^2?, [Pt(NH₃)Cl₃]^? and cis-[Pt(NH₃)₂Cl₂]) were between 0.1 and 2.0% (relative standard deviation); intermediate precisions were between 1.4 and 2.0% and accuracies were between 98.6 and 101.4%. Limits of detection of [PtCl₄]^2?, [Pt(NH₃)Cl₃]^? and cis-[Pt(NH₃)₂Cl₂] were 6 µg · ml^?1, 13 mg · ml^?1 and 5 µg · ml^?1 respectively, limits of quantification of [PtCl₄]^2?, [Pt(NH₃)Cl₃]^? and cis-[Pt(NH₃)₂Cl₂] were 51 µg · ml^?1, 55 mg · ml^?1 and 20 µg · ml^?1 respectively.     

REACTIONS OF CARBONYLSULPHIDE WITH [Rh(PPh3)3CI] AND [Pt(PPh3)3]

Abstract

Activation of small inorganic molecules (H₂, N₂, O₂, CO, NO, CO₂, SO₂, CS₂) by the complexes of transition metal ions like Rh(I), Ir(I), Pt(O) and Ru(II) have gained considerable interest during the last decade.^1–8 Because of the similarity of CO₂ and CS₂ molecules with COS, one would expect COS to form complexes with the transition metal ions analogous to those of CO₂ and CS₂. In addition, COS being susceptible to decomposition into CO and S, could also form carbonyl complexes. Until now, the only reaction of COS that has been successfully carried out is with [Pt(PPh₃)₃] which resulted in the formation of [Pt(COS)(PPh₃)₂] and [Pt₂S(CO) (PPh₃)₃]. ^8,9 It will, therefore, be interesting to study further the reactions of COS with the complexes of transition metal ions. The results of a preliminary study of such reactions with [Rh(PPh₃)₃Cl] and [Pt(PPh₃)₃] are reported in this communication.     

An electrical conductivity (EC) study of the thermal dissociation of [Co(NH3)6]X3 and [Co(en)3]X3 complexes

The thermal dissociation of the [Co(NH₃)₆]X₃ (X = Cl^?, Br^?, I^?, and NO^?₃), [Co(en)₃]X₃ (X = Cl^?, Br^?, I^?, NO^?₃, HSO^?₄ and $\text{1}\text{2}$ C₂O^2?₄), cis- [Co(en)₂Cl₂]Cl, and trans-[Co(en)₂ClBr]NO₃ complexes was investigated by an electrical conductivity (EC) technique. During the thermal dissociation reactions, liquid or semi-liquid phases are formed which cause large increases in the EC of the compound. The effect of concentration of the complex in a matrix medium as well as the composition of the matrix material on the EC curves were also determined.     

Halide Abstraction from Organic Solvents in Reactions of a Copper(I) Alkoxide: Synthesis and Crystal Structures of [Cu5(dppm)(dppm−)2(OtBu)Cl2] and [Cu3(dppm)3Br2][CuBr2]

The synthesis and structures of the two Cu^I halide complexes [Cu₅(dppm)(dppm^?)₂(O^tBu)Cl₂] and [Cu₃(dppm)₃Br₂][CuBr₂] (dppm = Ph₂PCH₂PPh₂, dppm^? = [Ph₂PCHPPh₂]^?) are reported. The compounds were obtained by treating reaction mixtures of [CuO^tBu] and dppm with dichloromethane or dibromomethane.     

Synthesis of ylideplatinum(II) complexes via α-functionalised alkylplatinum(II) intermediates and some comparative data on palladium(II) complexes; X-ray structure of trans-[Pt(CH2PEt3)I(PEt3)2]I

The reaction of [Pt(PEt₃)₃] with CH₂I₂ affords trans-[Pt(CH₂PEt₃)I(PEt₃)₂]I and is believed to proceed via the α-functionalised alkyl cis-[Pt(CH₂I)I(PEt₃)₂], because similar ylides are obtained from cis- or trans-[PT(CH₂X)(PPh₃)₂X] (XCl, Br, or I) with PR₃ (PEt₃, PBu₃ⁿ, PMePh₂, PEtPh₂, or PPh₃); cis-[Pd(CH₂I)-I(PPh₃)₂] does not react with excess PPh₃, but with PEt₃ yields trans-[Pd(CH₂PEt₃)I(PPh₃)₂]I; the X-ray structure of trans-[Pt(CH₂PEt₃)I(PEt₃)₂]I (current R = 0.045) shows PtP(1) 2.332(7), PtP(2) 2.341(8), PtC 2.08(2), and PtI 2.666(2) Å, and angles (a) C(1)PtI, P(1), P(2): 176.9(8), 91.6(6), 93.4(6), (b) IPtP(1), P(2): 87.1(2), 88.5(2), and (c) P(1)P(2), 166.8(3), and (d) PtC(1)P(3), 118(1)°.     

Monodentate imido and bidentate aminophenolate coordination of 2-aminophenol in rhenium(V) complexes

Reactions of trans-[ReOCl₃(PPh₃)₂] and trans-[ReO(OEt)I₂(PPh₃)₂] with 2-aminophenol (H₂ap) in acetonitrile led to the formation of cis-[ReOCl₂(Hap)(PPh₃)] (1) and trans-[Re(ap)(Hap)I(PPh₃)₂]I (2), respectively. The X-ray crystal structures show that Hap is coordinated as a bidentate chelate via the neutral amino nitrogen and deprotonated phenolate oxygen, and ap is coordinated as a monodentate through the imido nitrogen. The complexes have been characterized by IR spectroscopy, NMR spectrometry and X-ray crystallography. The bite angle of the Hap chelate is 76.9(1)° and 76.0(1)° in 1 and 2, respectively.     

Coordination behaviour of the multidentate Schiff base 2,6-bis(2-hydroxyphenyliminomethyl)pyridine towards the fac-[Re(CO)3] and [ReO] cores

The seven-coordinate rhenium(III) complex cation [Re^III(dhp)(PPh₃)₂]⁺ was isolated as the iodide salt from the reaction of cis-[Re^vO₂I(PPh₃)₂] with 2,6-bis(2-hydroxyphenyliminomethyl)pyridine (H₂dhp) in ethanol. In the complex fac-[Re(CO)₃(H₂dhp)Br], prepared from [Re(CO)₅Br] and H₂dhp in toluene, the H₂dhp ligand acts as a neutral bidentate N,N-donor chelate. The complexes were characterized by elemental analysis, infrared and ¹H NMR spectroscopy and X-ray crystallography.     

Reactivity of [Mo(NHNRPh)(NNRPh)(acac)X2] (R=Ph,Me; X=Br,I) toward tertiary phosphines

The reactivity of mixed [organohydrazido(1-)][organohydrazido(2-)]molybdenum(VI) complexes [Mo(NHNRPh)(NNRPh)(acac)X₂] {R?=?Ph, X?=?Br (1); R?=?Ph, X?=?I (2) and R?=?Me; X?=?I (3)} with tertiary phosphines as PPh₃, PMePh₂ and PMe₂Ph are examined. The syntheses of [Mo(NNPh₂)₂Br₂(PPh₃)] (4), [Mo(NNPh₂)₂Br₂(PMePh₂)₂] (5), [Mo(NNPh₂)₂Br₂(PMe₂Ph)₂] (6), [Mo(NNPh₂)₂(acac)I(PPh₃)] (7), [Mo(NNPh₂)₂(acac)(PMePh₂)₂]⁺I^? (8) and [Mo(NNMePh)₂(acac)(PMePh₂)₂]⁺I^? (9) are reported. All complexes were characterized by elemental analysis, UV-visible, IR, ¹H and ³¹P{H} NMR spectroscopy.     

Zur oxidativen Addition von komplexierten Phosphanen bzw. Arsanen an Platin(0)‐Komplexen

Oxidative Addition Reactions of Complexed Phosphine and Arsine at Platinum(0) Complexes The reactions of E(SiMe₃)₃ with [W(CO)₅thf] yield after alcoholysis in a one‐pot reaction the complexes [(CO)₅WEH₃] ( 1 ) (E = P( a ), As( b )). This procedure circumvents the direct use of gaseous phosphine and arsine, respectively. Complexes 1 react with [(C₂H₄)Pt(PPh₃)₂] in an oxidative addition type reaction to form the heterometallic complexes [(PPh₃)₂Pt(H){(μ‐EH₂)W(CO)₅}] (E = P( 2 ), As( 3 )). Complexes 2 and 3 were obtained as mixtures of their cis‐ and trans‐isomers, in which the contents of the trans‐isomer dominates. The products were comprehensively spectroscopically characterised, and the structures of the trans‐complexes 2 and 3 were determined by X‐ray crystal structure analysis.     

Disproportionation of rhenium(V). Imidazolate coordination of pyridylbenzimidazole in a rhenium(III) complex

Reaction of trans-[ReOCl₃(PPh₃)₂] with 2-(2′-pyridyl)benzimidazole (pbiH) in methanol led to the isolation of the rhenium(III) compound [ReCl₂(pbi)(PPh₃)₂] (1). Complex 1 could also be prepared in better yield by the reduction of [ReO₄]^? with PPh₃ in the presence of pbiH and hydrochloric acid. An X-ray crystallographic study showed that pbi is coordinated as a bidentate monoanionic chelate, with deprotonation of the imidazolyl NH group. The PPh₃ ligands are trans to each other.