Isolation of dithiocarbamate anions as salts of biscyclopentadienyl titanium(IV) chelates

A series of [Cp₂TiL]⁺[RR′NCS₂]^? complexes, where L is the conjugate base of acetylacetone, benzoylacetone or 8-hydroxyquinoline and R = CH₃, R′ = C₆H₅CH₂; R = C₂H₅, R′ = C₆H₄CH₃; R = H, R′ = C₅H₉; RR′ = C₆H₁₂, have been synthesised in aqueous medium by the reaction of [Cp₂TiL]⁺Cl^? with RR′NCS^?₂Na⁺. Conductivity measurements in nitrobenzene solution indicate that these complexes are electrolytes. Both the IR and NMR studies demonstrate that the ligand L is chelating in all these complexes. Consequently, tetrahedral coordination about the titanium atom is proposed. In addition to these studies, elemental analyses and magnetic susceptibility have been carried out for these complexes.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden: XI. Einige neuartige η1-vinyl-komplexe des eisens durch deprotonierung kationischer carbenkomplexe mit trimethyl(methylen)phosphoran

Novel η¹-vinyl complexes of the type Cp(CO)(L)FeC(OMe)C(R)R′ (R = R′ = H, Me; R = H, R′ = Me; L = Me₃P, Ph₃P) are obtainied via methylation of the acyl complexes Cp(CO)(L)FeC(O)R (R = Me, Et, i-Pr) with MeOSO₂F and subsequent deprotonation of the resulting carbene complexes [Cp(CO)(L)FeC(OMe)R]SO₃F with the phosphorus ylide Me₃PCH₂. The same procedure can be applied for the synthesis of the pentamethylcyclopentadienyl derivative C₅Me₅(CO)(Me₃P)FeC(OMe)CH₂, while treatment of the hydroxy or siloxy carbene complexes [Cp(CO)(L)FeC(OR)Me]X (R = H, Me₃Si; X = SO₃CF₃) with Me₃CH₂ results in the transfer of the oxygen bound electrophile to the ylidic carbon. Some remarkable spectroscopic properties of the new complexes are reported.     

Methyl- and phenyl-bis(tertiary phosphine) N-bonded carboxamido complexes of platinum(II)

Methyl- or phenylN-carboxamido-complexes of platinum(II) Pt(NHCOR')RL₂ (L = PEt₃, R = Me, R′ = Me, CH = CH₂; L = PEt₃, R = Ph, R′ = Me; L = PMe₂Ph, R = Ph, R′ = Me, Ph; L = PMePh₂, R = Ph, R′ =₃, R = Ph, R′ = Me) have been prepared by the reaction of KOH with cationic nitrile complexes [PtR(NCR′)L₂]BF₄. Thermally unstable hydrido-N-carboxamido-complexes could be detected spectroscopically. IR and NMR (¹H, ³¹P) spectra of some of the complexes indicate the existence of a solvent- and temperature-dependent equilibrium between syn-and anti-isomers arising from restricted rotation about the NC bond of the carboxamido-group. The anti-isomer is favoured by nonpolar solvents and by increasing bulk of L. In the complex [PtH(NCCH CH₂)(PEt₃)₂]BF₄, IR and NMR spectra show acrlonitrile to be bound through nitrogen, not through the olefinic CC bond.     

Six-membered palladacycles formed by cyclopalladation of 2-anilinopyridine derivatives

Summary Reactions of palladium(II) chloride with 2-substituted pyridines (HL), 2-(p-R-C₆H₄-Y)-C₅H₄N (R = H, CH₃, Cl; Y= NH, NCH₃, O, S, CH₂) form 12 complexestrans-[PdCl₂(HL)₂], HL being coordinated through a pyridine-N atom. When the ratio PdCl₂/HL = 1/1, the pyridine derivatives with Y = NH are cyclopalladated to form another type of complexes [PdClL]₂. In [PdClL]₂ the deprotonated ligand L is chelated through pyridine-N and phenylortho-C atoms forming an unusual six-membered palladacycle. Like other cyclopalladated complexes containing a five-membered palladacycle, [PdClL]₂ reacts with pyridine (py) to form adducts [PdClL(py)]. [Pd(acac)L] and [Pd(dtc)L] were also prepared and characterized (acac=acetylacetonate and dtc =N,Ndimethyldithiocarbamate ion).     

Organometallic and organobimetallic complexes of platinum(II) containing 2,2′-bipyrimidyl: syntheses and spectroscopic characteristics

Preparations are described of several monometallic complexes (bipym)PtR₂ [bipym = 2,2′-bipyrimidyl; R = Me, CF₃, Ph, 1-adamantylmethyl (adme); R₂ = (CH₂)₄] and bimetallic analogues R₂Pt(μ-bipym)PtR′₂ [R = R′ = CH₃, C₆H₅, adme; R = CH₃, R′ = Ph, adme, CF₃]. IR, ¹H NMR and UV/visible spectroscopic characteristics of the two modes of bipyrimidyl coordination are discussed.     

SYNTHESIS AND CHARACTERISATION OF DIORGANOANTIMONY(III) COMPLEXES OF THIOSEMICARBAZONES

Abstract

The interaction of the sodium salts of thiosemicarbazones with diphenylantimony chloride in 1:1 molar ratio in benzene solution lead to the formation of derivatives, Ph₂Sb[SC(NH₂)NN: C(R)R′] where R = H; R′ [dbnd] C₆H₅, CH₃OC₆H₄, C₆H₅CH[dbnd]CH, and R′ [dbnd] CH₃; R′[dbnd]C₆H₅, CH₃OC₆H₄, C₆H₄CH₃, respectively. The resulting complexes have been characterised on the basis of elemental analyses and molecular weight determination. The mode of bonding of the ligands with the metal atom has been proposed on the basis of I.R., ¹H and ¹³C NMR studies. All these ligands are found to behave as monofunctional bidentate moiety in these complexes.     

The preparation and characterisation of a series of cationic bimetallic linear triphos-bridged complexes of the type [Mo (CO) (L,L′ or L″–P) (η2-RC2R′)Cp] [BF4] {L,L′ or L″= [WI2 (CO){PhP(CH2CH2PPh2)2–P,P′} (η2-RC2R′)] (L,R=R′=Me; L′,R=R′=Ph; L″,R=Me,R′=Ph}

Equimolar quantities of [Mo (CO) (η²-RC₂R′)₂Cp] [BF₄] (R=R′=Me Ph R=Me R′=Ph) and L L′ or L″ {L L′ or L″= [WI₂ (CO){PhP(CH₂CH₂PPh₂)₂-PP′} (η²-RC₂R′)]} (L R=R′=Me L′ R=R′=Ph L″ R=Me R′=Ph) react in CH₂Cl₂ at room temperature to give the new bimetallic complexes[Mo (CO) (L L′ or L″–P) (η²-RC₂R′)Cp] [BF₄] (1–9) via displacement of the alkyne ligand on the molybdenum centre The complexes have been characterised by elemental analysis IR and ¹ H NMR spectroscopy and in selected cases by ³¹ P NMR spectroscopy.     

Synthesis reactivity and electrochemical properties of substituted cyclopentadienyl cobalt (III) complexes

Cyclopentadienyl cobalt complexes (η⁵‐C₅H₄R) CoLI₂ [L = CO,R=‐COOCH₂CH=CH₂ (3); L=PPh₃, R=‐COOCH₂‐CH=CH₂ (6); L=P(p‐C₆H₄O₃)₃, R = ‐COOC(CH₃) = CH₂ (7), ‐COOCH₂C₆H₅ (8), ‐COOCH₂CH = CH₂ (9)] were prepared and characterized by elemental analyses, ¹H NMR, ER and UV‐vis spectra. The reaction of complexes (η⁵‐C₅H₄R)CoLI₂ [L= CO, R= ‐COOC(CH₃) = CH₂ (1), ‐COOCH₂C₆H₅(2); L=PPh₃, R=‐COOC (CH₃) = CH₂ (4), ‐COOCH₂C₆H₅ (5)] with Na‐Hg resulted in the formation of their corresponding substituted cobaltocene (η⁵‐C₅H₄R)₂ Co[R=‐COOC(CH₃) = CH₂ (10), ‐COOCH₂C₆H₅ (11)]. The electrochemical properties of these complexes 1–11 were studied by cyclic voltammetry. It was found that as the ligand (L) of the cobalt (III) complexes changing from CO to PPh₃ and P(p‐tolyl)₃, their oxidation potentials increased gradually. The cyclic voltammetry of α,α′‐substituted cobaltocene showed reversible oxidation of one electron process.     

Some novel triorganotin(IV) derivatives of β, δ-triketones

Thirty triorganotin(IV) derivatives of the type R₃Sn(R′COCHCOCH₂COR″) and [R₃Sn]₂ (R′COCHCOCHCOR″) (where R = CH₃, C₂H₅, nC₃H₇, nC₄H₉ and C₆H₅ and R′ = R″ = CH₃, C₆H₅ or R′ = C₆H₅, R″ = CH₃) have been synthesised by the interaction of R₃SnCl with mono- or disodium salt of 2, 4, 6-heptanetrione, 1-phenyl-1, 3, 5-hexanetrione and 1, 5-diphenyl-1, 3, 5-pentanetrione in 1:1 and 2:1 molar ratios, respectively. The complexes have been examined by their molecular weight, IR, PMR and elemental analyses and their tentative structures assigned. Both “Z” and “E” forms have been identified in the 1:1 complexes in equilibrium with the enol form containing five coordinate tin. The 2:1 derivatives contain one five- and other four coordinated tin(IV) except the phenyl analogue where both the tins are five coordinated.     

Quantum chemical study of nickel(II) complexes with cyclic diimine ligands on the base of bis[3,3′-iminopropyl]methylamine

A quantum chemical study of spatial and electronic structures of molecules in the frame complexes, bis[3,3′(RR′)-ketiminepropyl]methylamine nickel dichlorides, where R = H, CH₃, and R′ = H, CH₃, has been performed by DFT(B3LYP/LANL2DZ) method. The molecules of these complexes were found to be in a triplet state. Energy stability of the endo form of the complex molecules was shown. In the molecule of bis[3,3′-aldiminopropyl]methylamine nickel dichloride (R = R′ = H), a considerable strengthening of the bond Ni-N(amine) takes place when passing from the diamagnetic into paramagnetic state, and all bonds Ni-N become equivalent with respect to interatomic distance values. The topology analysis of the electron density for the complexes with R = R′ =H and R = R′ = CH₃ was carried out. It is stated that all Ni-N bonds are covalent in the molecules of paramagnetic complexes.     

The influence of the nature of the ligand,L, on the electrochemical behaviour of dinitrosyl molybdenum complexes,Mo(NO)2L2Cl2, in aprotic media

Electrochemical investigations of the reduction of dicationic, monocationic and neutral dinitrosyl molybdenum complexes in nitromethane and acetonitrile are reported. All the compounds with the general formulae: [Mo(NO)₂L₂L′₂]²⁺, [Mo(NO)₂L₂L′Cl]⁺ and Mo(NO)₂L₂Cl₂ (L = CH₃CN, CH₂CHCN, C₆H₅CN, C₅H₅N, P(C₆H₅)₃, L₂ = 2,2′-bipyridine, L′ = CH₃CN and L′₂ = 2,2′-bipyridine) are reducible by one electron to yield 19-electron complexes. The dicationic complexes undergo a reversible one-electron transfer. For the mono- and dichlorocomplexes, the one-electron transfer induces the facile exchange of the chloroligand in the 19-electron complexes except for L₂ = 2,2′-bipyridine. However, the exchange of the chloroligand is followed by the fast anation by Cl^? of the remaining 18-electron chlorocomplexes to afford [Mo(NO)₂Cl₃L]^? and [Mo(NO)₂Cl₄]^2? which are reducible at higher negative potentials than dichloro- and monochlorocomplexes. The multiple electrochemical step system is not catalytic, but of the electroactivation type.     

Arsenic annual survey covering the year 1971

The ¹H NMR and infrared spectra of a number of β-diketone, thio-β-diketone, and β-iminoketone derivatives of trimethylplatinum(IV) have been recorded. The spectra indicate that in the parent compounds [Pt(CH₃)₃L]₂, (L = β-iminoketone or thio-β-diketone) the β-iminoketones bridge via the γ-carbon atom as found in β-diketone complexes, while the thio-β-diketones bridge via sulfur atoms. Complexes of the type [Pt(CH₃)₃LR] (R = a neutral unidentate ligand) and [Pt(CH₃)₃BipyL] (Bipy = 2,2′-bipyridine) have also been studied.     

Mass spectra of some (Z)-α-Phenyl-β-(2-thienyl)acrylonitriles

The mass spectra of some (Z)α-(4-R′-phenyl)-β-(2-thienyl-5-R)acrylonitriles (R = H, CH₃, Br; R′ = H, CH₃O, CH₃, Cl, NO₂) at 70 eV are reported. Mass spectra exhibit pronounced molecular ions. The compound's where R = H, and CH₃ are characterized by the occurrence of a strong [M - H]⁺ peak. Moreover, in all the compounds a m/z 177 peak occurs. In the compounds where R = H, [M - HS]* and [M - CHS]* ions are present except the nitroderivatives. Where R = CH₃, [M - HS]⁺ ion occurs.     

Complexes carbeniques des ferroporphyrines: Preparation de complexes carbeniques comportant deux substituants electrodonneurs par alcoolyse ou thionolyse des complexes halogenocarbeniques correspondants

α-Halocarbeneporphyriniron complexes, Fe(P)(C(Cl)R) react with alcohols or thiols with substitution of the chlorine atom by OR′ or SR′ groups. This reaction has been used to obtain new carbeneporphyriniron complexes in which the carbene ligand is substituted by two electrodonating groups. The complexes Fe(P)(C(XR′)R) with XR′ = OCH₃ or OC₂H₅, R = CH₃ or (CH₃)₂CH and P = TPP (tetraphenylporphyrin) or TTP (tetratolylporphyrin) and with XR′ = SCH₂C₆H₅, R = CH₃ and P = TPP or TTP, have been isolated and fully characterized.     

Further studies on organonickel compounds: the synthesis of some new alkyl-, acyl- and cyclopentadienyl-derivatives and the crystal structure of trans-[Ni(CH2SiMe3)2(PMe3)2]

The complex [NiCl₂(PMe₃)₂] reacts with one equivalent of mg(CH₂CMe₃)Cl to yield the monoalkyl derivative trans-[Ni(CH₂CMe₃)Cl(PMe₃)₂], which can be carbonylated at room temperature and pressure to afford the acyl [Ni(COCH₂CMe₃)Cl(PMe₃)₂]. Other related alkyl and acyl complexes of composition [Ni(R)(NCS)(PMe₃)₂] (R = CH₂CMe₃, COCH₂CMe₃) and [Ni(R)(η-C₅H₅)L] (L = PMe₃, R = CH₂CMe₃, COCH₂CMe₃; L = PPh₃, R = CH₂CMe₂Ph) have been similarly prepared. Dialkyl derivatives [NiR₂(dmpe)] (R = CH₂SiMe₃, CH₂CMe₂Ph; dmpe = 1,2-bis(dimethylphosphine)ethane, Me₂PCH₂ CH₂PMe₂) have been obtained by phosphine replacement of the labile pyridine and NNN′N′-tetramethylethylenediamine ligands in the corresponding [Ni(CH₂SiMe₃)₂(py)₂] and [Ni(CH₂CMe₂Ph)₂(tmen)] complexes. A single-crystal X-ray determination carried out on the previously reported trimethylphosphine derivative [Ni(CH₂SiMe₃)₂(PMe₃)₂] shows the complex belongs to the orthorhombic space group Pbcn, with a = 14.345(4), b = 12.656(3), c = 12.815(3) Å, Z = 4 and R 0.077 for 535 independent observed reflections. The phosphine ligands occupy mutually trans positions P-Ni-P 146.9(3)° in a distorted square-planar arrangement.     

Synthesis,Structure and Reactivity of [1, 2‐Bis(diphenylphosphinite)ethane]bromotricarbonylmanganese(I) with Reactions of Phosphites,Phosphonites. and Phosphinites

The manganese carbonyl complex [MnBr(CO)₃ L ] ( 1 ), where L = Ph₂POCH₂CH₂OPPh₂, was prepared by reacting [MnBr(CO)₅] with the bidentate ligand 1, 2‐Bis(diphenylphosphinite)ethane. From this compound and the appropriate phosphite, phosphinite or phosphonite ligands were synthesized the complexes [MnBr(CO)₂ LL ′], where L ′ = P(OMe)₃ ( 2 ) or P(OEt)₃ ( 3 ) and [MnBr(CO)₃ L ′₂], where L ′ =PPh(OEt)₂ ( 4 ) or PPh₂(OEt) ( 5 ). The obtained compounds have been characterized by elemental analysis, mass spectrometry, IR and NMR (¹H, ¹³C and ³¹P) spectroscopies and X‐ray diffractometry for the complexes 1 , 4 and 5 .     

Carbonylrhodium complexes of pyridine ligands and their catalytic activity towards carbonylation of methanol

The cis‐[Rh(CO)₂ClL] (1) complexes, where L = 2‐methylpyridine (a), 3‐methylpyridine (b), 4‐methylpyridine (c), 2‐phenylpyridine (d), 3‐phenylpyridine (e), 4‐phenylpyridine (f), undergo oxidative addition reactions with various electrophiles, like CH₃I, C₂H₅I, C₆H₅CH₂Cl or I₂, to yield complexes of the types [Rh(CO)(COR)ClXL] (2) (where R = CH₃ (i), C₂H₅ (ii), X = I; R = C₆H₅CH₂ (iii), X = Cl) or [Rh(CO)ClI₂L] (3) and [Rh(CO)₂ClI₂L] (4). The pseudo‐first‐order rate constants of CH₃I addition with complexes 1 containing pyridine (g) and 2‐substituted pyridine (a and d) ligands were found to follow the order pyridine >2‐methylpyridine >2‐phenylpyridine. The catalytic activity of complexes 1 containing different pyridine ligands (a–g) on carbonylation of methanol was studied and, in general, a higher turnover number was obtained compared with that of the well‐known species [Rh(CO)₂I₂]^?. Copyright © 2002 John Wiley & Sons, Ltd.     

Über Cyanatverbindungen und deren reaktives Verhalten. XXI. Reaktionsverhalten von Niob(V)- und Tantal(V)-thiocyanat gegenüber N-Donatoren

Cyanate Compounds and their Reactivity. XXI. Reactivity of Niobium(V) and Tantalum(V) Thiocyanates to N-Donators M₂(NCS)₁₀ reacts with ammonia or primary and secondary aliphatic amines to complexes of the types [M(NCS)(NH₂)₂NH]_x, [M(NCS)₃(NHR)₂ H₂NR], or [M(NCS)₃(NR′₂)₂ HNR′₂], with N-heterocyclic amines in a first step to [M(NCS)₅L]-complexes and in a further step through a redox mechanism to [M(NCS)₄L₂] complexes. [M(NCS)₅(CH₃CN)] mCH₃CN reacts with ammonia, or primary amines in acetonitrile over acetamidine and amidinolytic cleavage of M-NCS bonds to complexes of the type [M(NCS)_a(NC(NHR″)CH₃)_b(CH₃C(NH)NHR″)]_x. The prepared compounds are characterized by analytical data, derivatographic measurements, and IR or visible absorption spectra (M = Nb, Ta; x = 2; R = n-C₄H₉; R′ = C₂H₅; L = pyridine or 4-methyl-pyridine; m = 0, 1, 2; a = 1 or 4; b = 4 or 1; R″ = H, n-C₄H₉).     

Synthesis of a new class of acylplatinum complexes derived from salicylaldehyde

The synthesis of a new class of acylplatinum complexes of composition [Pt(OC₆H₄CO)L_aL_b] L_a = L_b = PR₃, P(OR)₃, Ph₂PCH₂CH₂PPh₂, AsR₃; L_a = 2-picoline, 3-picoline, 4-picoline, ¹⁵NH₂{CH₂}₅CH₃, L_b = DMSO, is described. The complexes are synthesized from o-hydroxybenzaldehyde (salicylaldehyde) and K₂PtCl₄ and contain an organic chelating ligand bound to platinum via the phenolic oxygen and the aldehyde carbon. ¹H, ¹³C, ³¹P and ¹⁹⁵Pt NMR data for the new complexes are reported.     

Synthese und Charakterisierung von 2‐O‐funktionalisierten Ethylrhodoximen und ‐cobaloximen

Synthesis and Characterization of 2‐O‐Functionalized Ethylrhodoximes and ‐cobaloximes 2‐Hydroxyethylrhodoxime and ‐cobaloxime complexes L—[M]—CH₂CH₂OH (M = Rh, L = PPh₃, 1 ; M = Co, L = py, 2 ; abbr.: L—[M] = [M(dmgH)₂L] (dmgH₂ = dimethylglyoxime, L = axial base) were obtained by reaction of L—[M]^— (prepared by reduction of L—[M]—Cl with NaBH₄ in methanolic KOH) with BrCH₂CH₂OH. H₂O—[Rh]^—, prepared by reduction of H[RhCl₂(dmgH)₂] with NaBH₄ in methanolic KOH, reacted with BrCH₂CH₂OH followed by addition of pyridine yielding py—[Rh]—CH₂CH₂OH ( 3 ). Complexes 1 and 3 were found to react with (Me₃Si)₂NH forming 2‐(trimethylsilyloxy)ethylrhodoximes L—[Rh]—CH₂CH₂OSiMe₃ (L = PPh₃, 4 ; L = py, 5 ). Treatment of complex 1 with acetic anhydride resulted in formation of the 2‐(acet oxy)ethyl complex Ph₃P—[Rh]—CH₂CH₂OAc ( 6 ). All complexes 1 — 6 were isolated in good yields (55—71 %). Their identities were confirmed by NMR spectroscopic investigations ( 1 — 6 : ¹H, ¹³C; 1 , 4 , 6 : ³¹P) and for [Rh(CH₂CH₂OH)(dmgH)₂(PPh₃)]·CHCl₃·1/2H₂O ( 1 ·CHCl₃·1/2H₂O) and py—[Rh]—CH₂CH₂OSiMe₃ ( 5 ) by X‐ray diffraction analyses, too. In both molecules the rhodium atoms are distorted octahedrally coordinated with triphenylphosphine and the organo ligands (CH₂CH₂OH and CH₂CH₂OSiMe₃, respectively) in mutual trans position. Solutions of 1 in dmf decomposed within several weeks yielding a hydroxyrhodoxime complex “Ph₃P—[Rh]—OH”. X‐ray diffraction analysis exhibited that crystals of this complex have the composition [{Rh(dmg)(dmgH) (H₂O)(PPh₃)}₂]·4dmf ( 7 ) consisting of centrosymmetrical dimers. The rhodium atom is distorted octahedrally coordinated. Axial ligands are PPh₃ and H₂O. One of the two dimethylglyoximato ligands is doubly deprotonated. Thus, only one intramolecular O—H···O hydrogen bridge (O···O 2.447(9)Å) is formed in the equatorial plane. The other two oxygen atoms of dmgH^— and dmg^2—, respectively, act as hydrogen acceptors each forming a strong (intermolecular) O···H′—O′ hydrogen bridge to the H′₂O′ ligand of the other molecule (O···O′ 2.58(2)/2.57(2)Å).