Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XL. Über Lithium-alkenylmanganate(II)

Contributions to the Chemistry of Transition Metal Alkyl Compounds. XL. About Lithium Alkenylmanganates(II) MnCl₂ reacts with vinyl, 2,2-dimethylvinyl, allyl, and methallyl lithium giving rise to alkenyl manganates(II). In a pure state the compounds Li₂[Mn(CH?CH₂)₄] · 1.5 diox, Li₂[Mn(CH?C(CH₃)₂)₄] · 1.5 diox, Li₂[Mn(CH₂? CH?CH₂)₄] · 2.5 diox and Li₃[Mn(CH₂? C(CH₃)?CH₂)₅] · 2 diox were isolated. The compounds were characterized by elementary analysis, EPR and IR spectra, magnetic moments, and reactions with iodine.     

Transition metal catalyzed alternating copolymerizations of olefins and co

Well defined Pd(II) catalysts of the type (N′N)Pd(CH₃)(Solv.)⁺ B(Ar_f)₄- (Ar_f = −3, 5-(CF₃)₂C₆H₃) have been prepared for living alternating copolymerizations of olefins with CO. This talk will focus on the mechanistic details of chain growth as elucidated by ¹H and ¹³C NMR spectroscopy, model studies of key migratory insertion steps and synthesis and properties of various copolymers and block copolymers based on styrenes, CH₂=CHC₆H₄X [X = p-C(CH₃)₃, p-OC(O)CH₃, p-OC(O)C-t-Bu), p-NHC(O)(C-t-Bu)]. Use of the catalysts based on the C₂ symmetric, homochiral ligand 2, 2'-bis[2-[4(S)-(Alkyl)-1, 3-oxazolinyl]]propane [Alkyl = CH₃, CH(CH₃)₂] produces a copolymer, 1, with a highly isotactic microstructure and high optical activity in contrast to achiral ligands such as 1,10-phenanthroline which produce copolymers with predominantly syndiotactic microstructure.     

Zweikernige Palladium(II)‐, Platin(II)‐ und Iridium(III)‐Komplexe von Bis[imidazol‐4‐yl]alkanen

Dinuclear Palladium(II), Platinum(II), and Iridium(III) Complexes of Bis[imidazol‐4‐yl]alkanes The reaction of bis(1,1′‐triphenylmethyl‐imidazol‐4‐yl) alkanes ((CH₂)_n bridged imidazoles L(CH₂)_nL, n = 3–6) with chloro bridged complexes [R₃P(Cl)M(μ‐Cl)M(Cl)PR₃] (M = Pd, Pt; R = Et, Pr, Bu) affords the dinuclear compounds [Cl₂(R₃P)M–L(CH₂)_nL–M(PR₃)Cl₂] 1 – 17 . The structures of [Cl₂(Et₃P)Pd–L(CH₂)₃L–Pd(PEt₃)Cl₂] ( 1 ), [Cl₂(Bu₃P)Pd–L(CH₂)₄L–Pd(PBu₃)Cl₂] ( 10 ), [Cl₂(Et₃P)Pd–L(CH₂)₅L–Pd(PEt₃)Cl₂] ( 3 ), [Cl₂(Et₃P)Pt–L(CH₂)₃L–Pt(PEt₃)Cl₂] ( 13 ) with trans Cl–M–Cl groups were determined by X‐ray diffraction. Similarly the complexes [Cl₂(Cp*)Ir–L(CH₂)_nL–Ir(Cp*)Cl₂] (n = 4–6) are obtained from [Cp*(Cl)Ir(μ‐Cl)₂Ir(Cl)Cp*] and the methylene bridged bis(imidazoles).     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XLIV. Zur Bildung von Tetraorganylzirconaten(II)

Contributions to the Chemistry of Transition Metall Alkyl Compounds. XLIV. Formation of Tetraorganylzirconates(II) Zirconiumtetraorganyls are reduced by n-butyl lithium with formation of dilithium tetraorganyl zirconates(II). Li₂[Zr(CH₂C₆H₅)₄] and Li₂[Zr(CH₃)₄] were isolated in a definite form as extremely air sensitive compounds, from which a polymer structure can be assumed. The compounds were characterized by elementary analysis, hydrolyses products, reactions with iodine, magnetic moments, and the ESR spectra.     

Strength of the PtCS2 bond in Pt(PPh3)2(CS2)

The enthalpy of the reaction: Pt(PPh₃)₂(CH₂CH₂)(cryst.) + CS₂(g) → Pt(PPh₃)₂(CS₂)(cryst.) + CH₂CH₂(g) has been determined as ΔH = ? 4.40 ± 2.2 kJ mol^?1 from solution calorimetry, and the bond dissociation energy D(PtCS₂) shown to be slightly greater than D(PtC₂H₄).     

Nafion-lnduced Metal-Metal Interactions in a Platinum（Ⅱ） Terpyridyl Acetylide Complex： a Luminescent Sensor for Detection of Volatile Organic Compounds

The platinum(Ⅱ) terpyridyl acetylide complex [Pt(terpy)(C≡CR)]ClO4 (terpy=2,2‘ : 6‘2“-terpyridine, R=CH2CH2CH3) (1) was incorporated into Nation membranes. At high loading the dry membranes exhibit intense photoluminescence with λmax at 707 nm from the ^3MMLCT state, which was not observed in fluid solution. Upon exposure to the vapor of polar volatile organic compounds (VOC), this photoluminescence was significantly red-shifed. This process was fully reversible when the VOC-incorporated membrane was dried in air. The dramatic and reversible changes in the emission spectra made the Nation-supported complex as an interesting sensor candidate for polar VOC.     

Molekülstruktur und thermische Stabilität des metallacyclischen Platin(II)‐Komplexes [Li(TMEDA)]2Pt(CH2CMe2CMe2CH2)2

Molecular Structure and Thermal Stability of the Metallacyclic Platinum(II) Complex [Li(TMEDA)]₂Pt(CH₂CMe₂CMe₂CH₂)₂ The X‐ray investigation at the “ate‐complex” [Li(TMEDA)]₂Pt(CH₂CMe₂CMe₂CH₂)₂ ( 1 ) revealed a new structure type of homoleptic organometallic compounds of platinum(II). Differences of the molecular structure of the “ate‐complex” [Li(TMEDA)]₂Pt(CH₂CH₂CH₂CH₂)₂ ( 2 ) as well as similarities to the structure of the homologeous “ate‐complex” of nickel(II) [Li(TMEDA)]₂Ni(CH₂CMe₂CMe₂CH₂)₂ ( 3 ) are described. A possible mechanism of the thermal decomposition of the complex 1 is discussed.     

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.     

Coordination chemistry of sulfines : I. Synthesis and characterization of the complexes Pt(PPh3)2(XYCSO) (X,Y = aryl,S-aryl,S-alkyl,Cl). Coordination via the CS-π-bond

Reactions of Pt(PPh₃)₄ with the sulfines, XYCSO, (X, Y = aryl, S-aryl, S-alkyl, Cl) yield coordination compounds of the type Pt(PPh₃)₂(XYCSO). Infrared, ³¹P and ¹H NMR spectra reveal that in all cases the sulfine ligand is coordinated side-on via the CS π-bond (Pt—η²-CS). Reactions of Pt(PPh₃)₄ with either the E- or Z-isomer of (p-CH₃C₆H₄)(CH₃S)CSO yields the corresponding E- or Z-coordination compound, Pt(PPh₃)₂[E-(p-CH₃C₆H₄)(CH₃S)CSO] or Pt(PPh₃)₂[Z-(p-CH₃C₆H₄)(CH₃S)CSO], indicating that the configuration of the sulfine ligand is retained upon coordination to the Pt(PPh₃)₂ unit. The compounds Pt(PPh₃)₂(XYCSO), containing reactive CX and/or CY bonds (X, Y = S-aryl, S-alkyl, Cl), undergo a rearrangement in solution to give complexes of the type PtX(PPh₃)₂(YCSO).     

“Roll‐over” Cyclometalation of 2,2′‐Bipyridine Platinum(II) Complexes in the Gas Phase: A Combined Experimental and Computational Study

In a combined experimental/computational investigation, the gas‐phase behavior of cationic [Pt(bipy)(CH₃)((CH₃)₂S)]⁺ ( 1 ) (bipy=2,2′‐bipyridine) has been explored. Losses of CH₄ and (CH₃)₂S from 1 result in the formation of a cyclometalated 2,2′‐bipyrid‐3‐yl species [Pt(bipy?H)]⁺ ( 2 ). As to the mechanisms of ligand evaporation, detailed labeling experiments complemented by DFT‐based computations reveal that the reaction follows the mechanistically intriguing “roll‐over” cyclometalation path in the course of which a hydrogen atom from the C(3)‐position is combined with the Pt‐bound methyl group to produce CH₄. Activation of a C? H‐bond of the (CH₃)₂S ligand occurs as well, but is less favored (35 % versus 65 %) as compared to the C(3)? H bond activation of bipy. In addition, the thermal ion/molecule reactions of [Pt(bipy?H)]⁺ with (CH₃)₂S have been examined, and for the major pathway, that is, the dehydrogenative coupling of the two methyl groups to form C₂H₄, a mechanism is suggested that is compatible with the experimental and computational findings. A hallmark of the gas‐phase chemistry of [Pt(bipy?H)]⁺ with the incoming (CH₃)₂S ligand is the exchange of one (and only one) hydrogen atom of the bipy fragment with the C? H bonds of dimethylsulfide in a reversible “roll‐over” cyclometalation reaction. The Pt^II‐mediated conversion of (CH₃)₂S to C₂H₄ may serve as a model to obtain mechanistic insight in the dehydrosulfurization of sulfur‐containing hydrocarbons.     

A study of some amine,pyridine and 3,5-lutidine complexes of trimethylplatinum(IV)

The reactions of trimethylplatinum(IV) compounds with a number of amines have been examined. With ammonia and methylamine, tris-and mono(amine)species have been obtained, but no bis(amine)species apart from [pt(CH₃)₃(NH₃)₂I]. With ethylamine the bis(amine)species is formed with excess ligand. The ¹H NMR spectra of [Pt(CH₃)₃LI]₂ (L=pyridine, 3,5-lutidine) exhibit evidence for two isomers in solution and an equilibrium of these compounds with [Pt(CH₃)₃L₂I] and [Pt(CH₃)₃I]₄.     

Zur Reaktivität von alkylthioverbrückten 44‐CVE‐triangularen Platinclustern: Umsetzungen mit bidentaten Phosphanliganden

On the Reactivity of Alkylthio Bridged 44 CVE Triangular Platinum Clusters: Reactions with Bidentate Phosphine Ligands The 44 cve (cluster valence electrons) triangular platinum clusters [{Pt(PR₃)}₃(μ‐SMe)₃]Cl (PR₃ = PPh₃, 2a ; P(4‐FC₆H₄)₃, 2b ; P(n‐Bu)₃, 2c ) were found to react with PPh₂CH₂PPh₂ (dppm) in a degradation reaction yielding dinuclear platinum(I) complexes [{Pt(PR₃)}₂(μ‐SMe)(μ‐dppm)]Cl (PR₃ = PPh₃, 3a ; P(4‐FC₆H₄)₃, 3b ; P(n‐Bu)₃; 3e ) and the platinum(II) complex [Pt(SMe)₂(dppm)] ( 4 ), whereas the addition of PPh₂CH₂CH₂PPh₂ (dppe) to cluster 2a afforded a mixture of degradation products, among others the complexes [Pt(dppe)₂] and [Pt(dppe)₂]Cl₂. On the other hand, the treatment of cluster 2a with PPh₂CH₂CH₂CH₂PPh₂ (dppp) ended up in the formation of the cationic complex [{Pt(dppp)}₂(μ‐SMe)₂]Cl₂ ( 5 ). Furthermore, the terminal PPh₃ ligands in complex 3a proved to be subject to substitution by the stronger donating monodentate phosphine ligands PMePh₂ and PMe₂Ph yielding the analogous complexes [{Pt(PR₃)}₂(μ‐SMe)(μ‐dppm)]Cl (PR₃ = PMePh₂, 3c ; PMe₂Ph, 3d ). NMR investigations on complexes 3 showed an inverse correlation of Tolmans electronic parameter ν with the coupling constants ¹J(Pt,P) and ¹J(Pt,Pt). All compounds were fully characterized by means of NMR and IR spectroscopy. X‐ray diffraction analyses were performed for the complexes [{Pt{P(4‐FC₆H₄)₃}}₂(μ‐SMe)(μ‐dppm)]Cl ( 3b ), [Pt(SMe)₂(dppm)] ( 4 ), and [{Pt(dppp)}₂(μ‐SMe)₂]Cl₂ ( 5 ).     

Synthesen und NMR‐Untersuchungen von Salzen mit den neuen Anionen [PtXn(CF3)6‐n]2— (n = 0 ‐ 5, X = F,OH, Cl,CN) und die Kristallstrukturanalyse von K2[(CF3)2F2Pt(μ‐OH)2PtF2(CF3)2]·2H2O

Syntheses and NMR Spectroscopic Ivestigations of Salts containing the Novel Anions [PtX_n(CF₃)_6‐n]^2— (n = 0 ‐ 5, X = F, OH, Cl, CN) and Crystal Structure of K₂[(CF₃)₂F₂Pt(μ‐OH)₂PtF₂(CF₃)₂]·2H₂O The first syntheses of trifluoromethyl‐complexes of platinum through fluorination of cyanoplatinates are reported. The fluorination of tetracyanoplatinates(II), K₂[Pt(CN)₄], and hexacyanoplatinates(IV), K₂[Pt(CN)₆], with ClF in anhydrous HF leads after working up of the products to K₂[(CF₃)₂F₂Pt(μ‐OH)₂PtF₂(CF₃)₂]·2H₂O. The structure of the salt is determined by a X‐ray structure analysis, P2₁/c (Nr. 14), a = 11.391(2), b = 11.565(2), c = 13.391(3)Å, β = 90.32(3)°, Z = 4, R₁ = 0.0326 (I > 2σ(I)). The reaction of [Bu₄N]₂[Pt(CN)₄] with ClF in CH₂Cl₂ generates mainly cis‐[Bu₄N]₂[PtCl₂(CF₃)₄] and fac‐[Bu₄N]₂[PtCl₃(CF₃)₃], but in contrast that of [Bu₄N]₂[Pt(CN)₆] with ClF in CH₂Cl₂ results cis‐[Bu₄N]₂[PtX₂(CF₃)₄], [Bu₄N]₂[PtX(CF₃)₅] (X = F, Cl) and [Bu₄N]₂[Pt(CF₃)₆]. In the products [Bu₄N]₂[PtX_n(CF₃)_6‐n] (X = F, Cl, n = 0—3) it is possibel to exchange the fluoro‐ligands into chloro‐ and cyano‐ligands by treatment with (CH₃)₃SiCl und (CH₃)₃SiCN at 50 °C. With continuing warming the trifluoromethyl‐ligands are exchanged by chloro‐ and cyano‐ligands, while as intermediates CF₂Cl and CF₂CN ligands are formed. The identity of the new trifluoromethyl‐platinates is proved by ¹⁹⁵Pt‐ and ¹⁹F‐NMR‐spectroscopy.     

Four‐ and Five‐Coordinate Gallium Complexes Stabilized by Bidentate 2‐(Dimethylaminomethyl)Pyrrole Ligand: Molecular Structures of Ga[NC4H3(CH2NMe2)‐2]3 and GaMe2[NC4H3(CH2NMe2)‐2]

Treatment of GaCl₃ with one equiv of Li[NC₄H₃(CH₂NMe₂)‐2] (n = 1, 2, 3) in diethyl ether at ?78 °C yields GaCl_3‐n[NC₄H₃(CH₂NMe₂)‐2]_n (n = 1, 1 ; n = 2, 2 ; n = 3, 3 ). Compound 1 reacts with two equiv of RLi to afford GaR₂[NC₄H₃(CH₂NMe₂)‐2] ( 4a, R=Me; 4b, R=Bu ) via transmetallation. Reacting 2 with one equiv of RLi in diethyl ether, 3 and 4 are formed via ligand redistribution. Variable temperature ¹H NMR spectroscopic experiments reveal that the five‐coordinate gallium compound 3 is fluxional and results in a coalescence temperature at 5 °C, at which ΔG^≠ is calculated at ca. 10.4 Kcal/mole. All the new compounds have been characterized by ¹H and ¹³C NMR spectroscopy and the structures of compounds 3 and 4a have also been determined by X‐ray crystallography.     

Reaktivität von Monophosphan-Platin(0)-Verbindungen gegenüber Schwefeldioxid

Reactivity of Monophosphine Platinum(0) Complexes with SO₂ . The addition reaction of (PPh₃)Pt(ViSi) (ViSi = {η²-H₂C?CHSiMe₂}₂O) ( 1 ) with SO₂ gives within 30 min the red SO₂ complex (PPh₃)Pt(η²-H₂C?CHSiMe₂- OSiMe₂CH?CH₂)(SO₂) ( 2 ). A reaction time of 24 h with SO₂ leads to the elimination of the ViSi ligand, and the unstable monomeric intermediate (PPh₃)Pt(SO₂) cyclo- trimerizes to the stable cluster [Pt(PPh₃)(SO₂)]₃ ( 3 ). 3 is also obtained within 30 min by the reaction of (PPh₃)Pt(C₂H₄)₂ ( 4 ) with SO₂. The crystal structure of 3 has been determined; space group P2₁/n, Z = 4, a = 1 606.1(3), b = 1 019.3(1), c = 3 624.6(5) pm, β = 93.67°, R/R_w = 0.102/0.121.     

Strukturen zweifach metallierter Derivate von 3, 3‐Dimethyl‐1, 5‐bis(trimethylsilyl)‐1, 5‐diaza‐pentan mit Lithium und Aluminium sowie zweier Donor‐substituierter Digallane

Structural Characterization of Bis(metallated) Derivatives of 3, 3‐Dimethyl‐1, 5‐bis(trimethylsilyl)‐1, 5‐diaza‐pentane with Lithium and Aluminum and of two Donor‐substituted Digallanes The diaminopropane derivative Me₂C[CH₂N(H)SiMe₃]₂ is metallated with n‐butyllithium and lithium tetrahydridoaluminate to obtain Me₂C[CH₂N(Li)SiMe₃]₂ and Me₂C[CH₂N(Li)SiMe₃][CH₂N(AlH₂)SiMe₃], respectively. Both compounds exhibit a central eight‐membered ring, Li₄N₄ or Li₂Al₂N₄. Me₂C[CH₂N(Li)SiMe₃]₂ reacts with Ga₂Cl₄ · 2dioxane under formation of the corresponding tetra(amino)digallane. This is monomeric, in contrast to a dimeric tetraalkoxy‐substituted digallane, Ga₄O^tBu₈. All compounds were characterized by single crystal X‐ray crystallography.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. XXXV. Zum Reaktionsverhalten von Tetrabenzyltitan gegenüber Lithiumalkylen

Contributions to the Chemistry of Transition Metal Alkyl Compounds. XXXV. Reactions in Tetrabenzyl Titanium/Alkyllithium Systems Organotitanium(IV) complexes of the type Li[(C₆H₅CH₂)₄TiR] (R = CH₃, C₂H₅, n-C₄H₉) were isolated from tetrabenzyl titanium and lithium alkyls at deep temperature. The reddish brown, crystalline compounds decompose between ?30 and 0°C with formation of benzyltitanates(II) which composition differs between Li₂[Ti(CH₂C₆H₅)₄] and Li[Ti(CH₂C₆H₅)₃]. From these complexes pure dibenzyl titanium can be isolated. The reaction mechanism is discussed. Experiments for isolation of a benzyl titanium(III) compound from (C₆H₅CH₂)₄Ti/RLi systems failed in all cases. Recent informations about stable tribenzyl titanium obtained from tetrabenzyl titanium and ethyl lithium could not be confirmed.     

On Mixed-Valence Dinuclear PtII,PtIII Nucleobase Complexes Derived from cis-Diamineplatinum(II): Effect of steric bulk of amine ligands on the Pt-oxidation state

A series of closely related dinuclear (head-head) Pt^II complexes of general composition cis-[a₂PtL₂Pta′₂]²⁺ with a,a′ = NH₃ or CH₃NH₂ and L = 1-methyluracilate-N3,O4 (1-MeU) or 1-methylthyminate-N3,O4 (1-MeT) has been prepared and the solution behavior toward Ce^IV oxidation studied. The X-ray crystal structure of a representative example cis-[(CH₃NH₂)₂Pt(1-MeU)₂Pt(CH₃NH₂)₂](ClO₄)₂ · 0.5 H₂O ( 1b ), has been determined: Monoclinic, space group P2₁/c, a = 11.907(7) Å, b = 19.087(14) Å, c = 12.525(7) Å, β = 90.49(4)°, Z = 4. Oxidation of these diplatinum(II) complexes ([Pt^2.0]₂) with Ce^IV in aqueous solution to the corresponding diplatinum(III) species ([Pt^3.0]₂) proceeds via tetranuclear [Pt^2.25]₄ or dinuclear [Pt^2.5]₂ mixed-valence state compounds, depending on the nature of the a′ ligands: with a′ = NH₃, blue green [Pt^2.25]₄ forms, whereas with a′ = CH₃NH₂, purple [Pt^2.5]₂ represents the intermediate. This difference is interpreted in terms of differences in bulk between NH₃ and CH₃NH₂ ligands trans to the O(4) positions of the bridging nucleobases which influence the ability of dinuclear species to associate via the O(4)₂ Pt a₂′ faces.     

Synthesen und Charakterisierungen der ersten Tris‐ und Tetrakis(trifluormethyl)palladate(II) und ‐platinate(II), [M(CF3)3(PPh3)]— und [M(CF3)4]2— (M = Pd,Pt)

Syntheses and Characterizations of the First Tris and Tetrakis(trifluoromethyl) Palladates(II) and Platinates(II), [M(CF₃)₃(PPh₃)]^— and [M(CF₃)₄]^2— (M = Pd, Pt) Tris(trifluoromethyl)(triphenylphosphino)palladate(II) and platinate(II), [M(CF₃)₃PPh₃]^—, and the tetrakis(trifluoromethyl)metallates, [M(CF₃)₄]^2— (M = Pd, Pt), are prepared from the reactions of [MCl₂(PPh₃)₂] and Me₃SiCF₃ / [Me₄N]F or [I(CF₃)₂]^— salts in good yields. [Me₄N][M(CF₃)₃(PPh₃)] crystallize isotypically in the orthorhombic space group Pnma (no. 62) with Z = 4. The NMR spectra of the new compounds are described.     

Study on synthesis of lanthanide chelates of fluorochloroalkyl β-diketones useful as shift reagents

Several lanthanide chelates of the fluorochloroalkyl β-diketones Ln(CF₂ClCOCHCOR)₃ ·nH₂O were prepared (2, Ln=Eu; 2a, R=C(CH₃)₃, n=0; 2b, R=C₆F₅, n=0; 2c, R=CF₂Cl, n=2. 3, Ln=Pr; 3a, R=C (CH₃)₃, n=0; 3b, R=C₆F₅, n=l; 3c, R=CF₂Cl, n=2. 4, Ln=La, R=C₆H₅, n=0) and the NMR shift data of compounds 2 and 3 had been determined using alcohols, ether, ketones and amine as substrates. With alcohol, ether and ketone, compounds 2 induces shifts similar to that induced by Eu (fod)₃. However due to the high solubility of the chelates in non-polar organic solvents such as CHCl₃ and CCl₄ and the absence of ¹H signal from compounds 2b and 2c, their application as a series of new ¹H NMR shift reagents seems promising.