Synthesis and crystal structure of the double cluster [Cp3Fe4(CO)4(C5H4)]2(p-C6H4)

[Cp₄Fe₄(CO)₄] (1) reacts with p-BrC₆H₄Li and MeOH in sequence to afford the functionalized cluster [Cp₃Fe₄(CO)₄(C₅H₄-p-C₆H₄Br)] (2), while the reaction of 2 with n-BuLi and MeOH produces [Cp₂Fe₄(CO)₄(C₅H₄Bu)(C₅H₄-p-C₆H₄Br)] (3). The double cluster [Cp₃Fe₄(CO)₄(C₅H₄)]₂(p-C₆H₄) (4) has been prepared by treatment of [Cp₄Fe₄(CO)₄] with p-C₆H₄Li₂ and MeOH in sequence. The electrochemistry of 2 and 4, as well as the crystal structure of 4 have been investigated.     

SNAr reactions of β-substituted porphyrins and the synthesis of meso substituted tetrabenzoporphyrins

Reaction of 2,3,7,8,12,13,17,18-octaethylporphyrin with LiR reagents containing functional groups readily yields meso substituted derivatives suitable for further transformations with residues such as -p-C₆H₅Br, -p-C₆H₅-CCH, -p-C₆H₅-NH₂ or -(CH₂)₃-CHCH₂. Similar reactions of tetrabenzoporphyrin with alkyllithium reagents afforded the first entry into meso mono- and dialkylsubstituted tetrabenzoporphyrins while reaction of bicyclo[2.2.2]oct-type masked isoindole precursors with LiR followed by in situ retro-Diels-Alder reaction also afforded the 5-phenyl and 5,10-diphenyltetrabenzoporphyrins in high purity.     

Synthesis of mononuclear and oligomeric ruthenium(II) acetylides

The complexes trans-[Ru(PMe₃)₄(CCPh)₂] and trans-[Ru(PMe₃)₄(CCC₆H₄C₆H₄CCSnMe₃)₂] have been prepared from the reaction between trans-[Ru(PMe₃)₄Cl₂] and an excess of either Me₃SnCCPh or Me₃SnCCRCCSnMe₃ (R = p-C₆H₄C₆H₄), respectively. However, if only one equivalent of the latter reagent is used the rod-like polymeric species trans-[-Ru(PMe₃)₄CCRCC-]_n can be isolated.     

ortho-, meta- and para-nitrophenylgold(I) complexes

Treatment of [BzPh₃P][AuCl₂] with [Hg(x-C₆H₄NO₂)₂] (x = o, m, or p) gives anionic gold(I) complexes of the type [BzPh₃P][Au(R)Cl](R = o-, m- or p-C₆H₄NO₂, Bz = C₆H₅CH₂). The chloro ligand in [Au(o-C₆H₄NO₂)Cl]^? can be replaced by bromo or iodo ligands by use of NaBr or NaI. The anions [Au(R)Cl]^? react with neutral monodentate ligands, L, to give neutral mononuclear complexes [Au(R)L] (R = o-C₆H₄NO₂, L = PPh₃, AsPh₃; R = m-C₆H₄NO₂, L = PPh₃) and with 1,2-bis(diphenylphosphino)ethane (dpe) to give [Au₂(R)₂(dpe)] (R = o-C₆H₄NO₂). The corresponding [Au(p-C₆H₄NO₂)Cl]^? reacts with PPh₃ or AsPh₃ to give mixtures containing [AuClL]. The anionic ortho-nitrophenylgold(I) complex is much more stable than its meta- or para-nitrophenyl isomers. These are thought to be the first reports of nitrophenylgold(I) complexes.     

C2-Bridged sandwich and half-sandwich entities with Ti(IV) and Cr(0) centers

The intense purple colored bi- and trimetallic complexes {Ti}(CH₂SiMe₃)[CC(η⁶-C₆H₅)Cr(CO)₃] (3) ({Ti}=(η⁵-C₅H₅)₂Ti) and [Ti][CC(η⁶-C₆H₅)Cr(CO)₃]₂ (5) {[Ti]=(η⁵-C₅H₄SiMe₃)₂Ti}, in which next to a Ti(IV) center a Cr(0) atom is present, are accessible by the reaction of Li[CC(η⁶-C₆H₅)Cr(CO)₃] (2) with {Ti}(CH₂SiMe₃)Cl (1) or [Ti]Cl₂ (4) in a 1:1 or 2:1 molar ratio. The chemical and electrochemical properties of 3, 5, {Ti}(CH₂SiMe₃)(CCFc) [Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)] and [Ti][(CC)_nMc][(CC)_mM′c] [n, m=1, 2; n=m; n≠m; Mc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄); M′c=(η⁵-C₅H₅)Ru(η⁵-C₅H₄); Mc=M′c; Mc≠M′c] will be comparatively discussed.     

Polythiolated complexes. Part 2(1). Palladium(II) and platinum(II) derivatives of polyfluorophenylthiolates

Summary The preparation and characterization of the new thiolate complexes [M(SR)₂(SEt₂)₂] (M=Pt, R=C₆F₅ orp-C₆HF₄) and [M(SR)₂]_n (M=Pd, R=C₆F₅,p-C₆HF₄ orp-C₆H₄F; M=Pt, R=p-C₆H₄F) is discussed. The tendency to form polymeric, rather than monomeric species, varies as follows: Pd>Pt; C₆H₄F>C₆HF₄> C₆F₅. [Pt(SC₆F₅)₂(SEt₂)₂] has atrans square planar coordination.     

Synthesis and structure of chiral-at-metal complexes with the ligand (S)-2-[(Sp)-2-(diphenylphosphino)ferrocenyl]-4-isopropyloxazoline

Half-sandwich complexes of formula [(ηⁿ-ring)MClL]PF₆ [L = (S)-2-[(S_p)-2-(diphenylphosphino)ferrocenyl]-4-isopropyloxazoline; (ηⁿ-ring)M = (η⁵-C₅Me₅)Rh; (η⁵-C₅Me₅)Ir; (η⁶-p-MeC₆H₄iPr)Ru; (η⁶-p-MeC₆H₄iPr)Os] have been prepared and spectroscopically characterised. The molecular structures of the rhodium and iridium compounds have been determined by X-ray crystallography. The related solvate complexes [(η⁵-C₅Me₅)ML(Me₂CO)]²⁺ (M = Rh, Ir) are active catalysts for the Diels-Alder reaction between methacrolein and cyclopentadiene.     

Synthesis of boron-containing tyrosine derivatives based on the closo-decaborate and closo-dodecaborate anions

A series of new boron-containing tyrosine derivatives [B _n H _n?1O(CH₂)₄O-4-C₆H₄CH₂CH-(NH₃)COOH]^? and [B _n H _n?1O(CH₂CH₂)₂O-4-C₆H₄CH₂CH(NH₃)COOH]^? (n = 10, 12) were prepared by ring opening of the cyclic oxonium derivatives of the decahydro-closo-decaborate and dodecahydro-closo-dodecaborate anions, respectively, with ethyl N-trifluoroacetyl-L-tyrosinate.     

Alkinylverbindungen von übergangsmetallen : XXXIX. Planare palladium(II) komplexe des typs trans-[p-C6H4(CCPd(X)(PEt3)2)2](n+2)+ (n = summe der ionenladungen von X)

Preparation and properties of the diamagnetic planar complexes trans-[p-C₆H₄(CCPd(X)(PEt₃)₂)₂] (X = Cl, Br, I, NCS) and trans-[p-C₆H₄(CCPd(X)(PEt₃)₂)₂](ClO₄)₂ (X = PEt₃, pyridine) are described. The structures of the compounds have been determined by ³¹P and ¹H NMR spectroscopy. The IR spectra are discussed.     

The reactions of [Fe2(η-C5H5)2(CO)4−n(CNMe)n] (n = 0–4) complexes with halogens and mercury(II) salts

Halogens, X₂, and HgY₂ (X = Cl, Br, I; Y = X, F, NO₃, BF₄) cleave the metalmetal bonds in [Fe₂(η-C₅H₅)₂(CO)_4−n(CNMe)_n] complexes (n = 0–4). Typically, e.g., when n = 2, X₂ electrophiles give [Fe(η-C₅H₅)(CO)(CNMe)X] (a) and [Fe(η-C₅H₅)(CO)(CNMe)₂]X (b) in relative yields which depend on X, the reaction solvent and n, but HgY₂ give equimolar amounts of [Fe(η-C₅H₅)(CNMe)₂Y] (c and [Fe(η-C₅H₅)(CO)₂HgY] only. Hg(CN)₂ reacts more slowly than other HgY₂, and [Hg(PPh₃)₂I₂] does not react at all. It is suggested that the reactions which give rise to products of type (a), (b) or (c) are all two-electron oxidation which proceed by way of adducts containing μ-CA → X₂ or μ-CA → HgX₂ groups (Ca = CO or CNMe). One of these adducts has been isolated, namely [Fe₂(η-C₅H₅)₂(CNMe)₂{μ-CN(Me)HgCl₂}₂] · CHCl₃.     

Synthesis of novel rigid rod iron metal containing polyyne polymers

Treatment of the dihaloiron-chelating phosphine complex, Fe(DEPE)₂Cl₂ (1) with 2.5 equivalents of Me₃SnCC₆H₅ (2) gives the monomeric complex, tras-Fe(DEPE)₂(CCC₆H₅)₂ (3, whereas the reaction of equimolar quantities of 1 and Me₃SnCCRCCSnMe₃ (R = p-C₆H₄ (4); p-C₃)₂C₆H₂ (5)) yields soluble and high molecular weight rigid rod polymeric species, trans-[-Fe(DEPE)₂(−CCRCC-)]_n (6,7).     

Transition metal derivatives of arenediazonium ions: XIV. Reactions of arenediazomolybdenum(II) complexes with neutral and anionic Lewis bases

The reactions of arenediazomolybdenum(II) complexes such as [(η-C₅H₅)Mo(N₂C₆H₄CH₃-p)I₂]₂, (η-C₅H₅)Mo(CO species with neutral and anionic monodentate or chelating ligands have been investigated. The new arenediazo complexes isolated from these reactions include neutral species such as (η-C₅H₅)Mo(PPh₃)(N₂C₆H₄CH₃-p)I₂ and (η-C₅H₅)Mo(N₂C₆H₄CH₃-p) cations of the type [η-C₅H₅)Mo(bipy)(N₂C₆H₄CH₃-p)I]⁺ and the anion [(η-C₅H₅)Mo(N₂C₆H₄CH₃-p)I₃]^?. The structures of the new complexes are discussed.     

Study on synthesis and properties of poly(ferrocenylbutylmethylsilane) with unsymmetrical silicon substitution groups

Novel poly(ferrocenylⁿbutylmethylsilane) with unsymmetrical silicon substitution groups [Fe(η-C₅H₄)₂(SiBuMe)]_n (PFBMS) (6) have been prepared via the thermal ring-opening polymerization (ROP) of the corresponding strained silicon-bridge [1] ferrocenophanes [Fe(η-C₅H₄)₂(SiBuMe)] (4) and via the nucleophilic substitution of poly(ferrocenylmethylchlorosilane) [Fe(η-C₅H₄)₂(SiMeCl)]_n (5) with n-butyllithium. Resultant PFBMS was structurally characterized by ¹H NMR and UV/visible spectroscopy. The molecular weights of PFBMS (6) were measured by gel permeation chromatography (GPC) using polystyrene standard, and the solution electrochemical behavior of PFBMS was investigated by cyclic voltammetry (CV).     

The reactions of AgY salts with [Fe2(η-C5H5)2(CO)4-n(CNMe)n] complexes (Y−  NO3−, BF4− or PF6−; n  0, 1 or 2). The crystal structure of [Fe(η-C5H5)2(CNMe)]BF4

The oxidative cleavage of [Fe₂(η-C₅H₅)₂(CO)_4-n(CNMe)_n] (n=0−2) by 2AgX gives mononuclear products. It is shown to be a two-electron process in most solvents but a one-electron process in acetonitrile. The two-electron oxidations proceed by way of adducts such as [Fe₂(η-C₅H₅)₂(CO)(CNMe)(μ-CO){;μ-CN(Me)AgPPh₃};]BF₄ which are isolable when n = 2, detectable when n = 1 and postulatetd when n = 0. The one-electron process gives no adducts, and 1AgX cleaves all of the substrate to [Fe(η-C₅H₅)(CO)(L)(NCMe)]⁺ and [Fe(η-C₅H₅)(CO)(L)]^. (L  CO or CNME). The latter may combine or react with added CHBr₃ to give [Fe(η-C₅H₅)(CO)(L)Br]. The structure of [Fe(η-C₅H₅)(CO)₂-(CNMe)]BF₄ has been determined by X-ray diffraction.     

Carbonyl rhodium(I) complexes with α-diimines ligands

The reactions of [Rh(CO)₂Cl]₂ with α-diimines, RN=CR′-CR′=NR (R = c-Hex, C₆H₅, p-C₆H₄OH, p-C₆H₄CH₃, p-C₆H₄OCH₃, R′ = H; R = c-Hex, C₆H₅, p-C₆H₄OH, p-C₆H₄OCH₃; R′ = Me) in 2:1 Rh/R-dim ratio gave rise to ionic compounds [(CO)₂Rh.R-dim(R′,R′)][Rh(CO)₂Cl₂] which have been characterized by elemental analyses, electrical conductivity, ¹H-NMR and electronic and IR spectroscopy. Some of these complexes must involve some kind of metal-metal interaction. The complex [Rh(CO)₂Cl.c-Hex-dim(H,H)] has been obtained by reaction of [Rh(CO)₂Cl]₂ with the c-Hex-dim(H,H) ligand in 1:1 Rh/R-dim ratio. The reactions between [(CO)₂Rh.R-dim(H,H)][Rh(CO)₂Cl₂](R = c-Hex or p-C₆H₄OCH₃) with the dppe ligand have been studied. The known complex RhCl(CO)(PPh₃)₂ has been isolated from the reaction of [(CO)₂Rh.R-dim(H,H)]-[Rh(CO)₂Cl₂] (R = c-Hex or p-C₆H₄OCH₃) with PPh₃ ligand.     

Optisch aktive übergangsmetall-komplexe: XXXIII. Substituenteneinfluss auf die racemisierungs geschwindigkeit von (+)579und(−)579−C5H5MN(COC6H5)(NO)P(pC6H4Y)3

In the reaction of [C₅H₅Mn(CO)₂(NO)] [X] ([X] = [BF₄], [PF₆]) with p-substituted triarylphosphines P(p-C₆H₄?Y)₃ [Y = CF₃, Cl, F, C₆H₅, CH₃, OCH₃, N(CH₃)₂] the asymmetric monosubstitution products [C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃] [X] are formed, which can be converted into the neutral esters C₅H₅Mn(COOC₁₀H₁₉)(NO)P(p-C₆H₄?Y)₃ by natrium menthoxide. The diastereoisomers (+)₅₇₉^? and (?)₅₇₉^?C₅H₅Mn(COOC₁₀H₁₉)(NO)P(p-C₆H₄?Y)₃ are separated by fractional crystallisation and transformed into the enantiomeric salts (+)₅₇₉^? and (?)₅₇₉-[C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃] [X] by cleavage with HCl and precipitation with NH₄PF₆. The (+)₅₇₉^? and (?)₅₇₉^? rotating salts in the reaction with LiC₆H₅ yield the carbonyl addition products (+)₅₇₉^? and (?)₅₇₉^? C₅H₅Mn(COC₆H₅)(NO)P(p-C₆H₄?Y)₃ and the ring addition products (+)₅₇₉^? and (?)₅₇₉^?(exo-C₆H₅)C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃, which can be separated by chromatography.The salts (+)₅₇₉^? and (?)₅₇₉^?[C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃] [X] and the cyclopentadiene complexes (+)₅₇₉^? and (?)₅₇₉-(exo-C₆H₅)C₅H₅Mn(CO)(NO)P(p-C₆H₄?Y)₃ are configurationally stable, whereas the esters (+)₅₇₉^? and (?)₅₇₉^?C₅H₅Mn(COOC₁₀H₁₉)(NO)P(p-C₆H₄?Y)₃ and the benzoyl complexes (+)₅₇₉^? and (?)₅₇₉^?C₅H₅Mn(COC₆H₅)(NO)P(p-C₆H₄?Y)₃ epimerise or racemise in solution.The rate of racemisation of the benzoyl compounds (+)₅₇₉^? and (?)₅₇₉C₅H₅Mn(COC₆H₅)(NO)P(p-C₆H₄?Y)₃ was measured polarimetrically in the temperature range 0–45° C. It turned out that electron-releasingsubstituents Y in the ligand P(p-C₆H₄?Y)₃ increase the half-lives, whereas electron-attracting substituents decrease the half-lives. There is a linear correlation between the σ-constants of the substituents and the rate constants of the racemisation (reaction constant p = +2.14).     

Resolution of cycloplatinated ferrocenylketimines

The resolution of cycloplatinated ferrocenylketimines was carried out by using S-leucine as chiral auxiliary and a pair of diastereomers was obtained. The optically active derivatives of the cycloplatinated ferrocenylketimines have been prepared and characterized. The structures and absolute configurations of (−)-(S_p,S)-[Pt{(η⁵-C₅H₃CMeNC₆H₄-4-CH₃)Fe(η⁵-C₅H₅)}(S-leu)] and (−)-(S_p)-[Pt{(η⁵-C₅H₃CMeNC₆H₄-4-Br)Fe(η⁵-C₅H₅)}(PPh₃)Cl] were determined by X-ray diffraction, on the basis of which the absolute configurations of other optically active compounds studied were ascertained.     

Insertion of isocyanides into the palladium-(2-pyridyl) bond

The reaction of the pyridyl-bridged binuclear complex [PdBr(μ-2-C₅H₄N)(PPh₃)]₂ with isocyynides CNR (R  p-C₆H₄OMe, Me, C₆H₁₁) yields the complex $\text{PdBr}${(&2.dbnd;NR)C(&2.dbnd;NR) (2-C₅H₄N)}(PPh₃)] containing a C,N-chelated 1,2-bis(imino)-2-(2-pyridyl)ethyl group, which results from successive insertions of two isocyanides molecules into the palladium2-pyridyl bond. The mononuclear compound trans-[PdBr(2-C₅H₄N)(PMePh₂)₂] readily reacts with various CNR ligands (R  p-C₆H₄OMe, Me, C₆H₁₁, CMe₃) to give the imino(2-pyridyl)methylpalladium(II) derivatives, trans-[Pdbr{C(=NR)(2-C₅H₄N)} (PMePh₂)₂].     

Ring-Opening Polymerisation of Low-Strain Nickelocenophanes: Synthesis and Magnetic Properties of Polynickelocenes with Carbon and Silicon Main Chain Spacers

Polymetallocenes based on ferrocene, and to a lesser extent cobaltocene, have been well-studied, whereas analogous systems based on nickelocene are virtually unexplored. It has been previously shown that poly(nickelocenylpropylene) [Ni(η⁵-C₅H₄)₂(CH₂)₃]_n is formed as a mixture of cyclic ( 6 _x ) and linear ( 7 ) components by the reversible ring-opening polymerisation (ROP) of tricarba[3]nickelocenophane [Ni(η⁵-C₅H₄)₂(CH₂)₃] ( 5 ). Herein the generality of this approach to main-chain polynickelocenes is demonstrated and the ROP of tetracarba[4]nickelocenophane [Ni(η⁵-C₅H₄)₂(CH₂)₄] ( 8 ), and disila[2]nickelocenophane [Ni(η⁵-C₅H₄)₂(SiMe₂)₂] ( 12 ) is described, to yield predominantly insoluble homopolymers poly(nickelocenylbutylene) [Ni(η⁵-C₅H₄)₂(CH₂)₄]_n ( 13 ) and poly(tetramethyldisilylnickelocene) [Ni(η⁵-C₅H₄)₂(SiMe₂)₂]_n ( 14 ), respectively. The ROP of 8 and 12 was also found to be reversible at elevated temperature. To access soluble high molar mass materials, copolymerisations of 5 , 8 , and 12 were performed. Superconducting quantum interference device (SQUID) magnetometry measurements of 13 and 14 indicated that these homopolymers behave as simple paramagnets at temperatures greater than 50 K, with significant antiferromagnetic coupling that is notably larger in carbon-bridged 6 _x /7 and 13 compared to the disilyl-bridged 14 . However, the behaviour of these polynickelocenes deviates substantially from the Curie–Weiss law at low temperatures due to considerable zero-field splitting.     

Inorganic Polymers : by N.H. Ray,Academic Press,New York/San Francisco/London, 1978, 174 pages, $ 17.35.

Insertion of CO or p-TolNC into a ZrC bond of [Zr(η-C₅H₅).(R)R′] under ambient conditions in C₆H₆ leads to the stable η²-acyl- or η²-iminoacyl-complex [Zr(η-C₅H₅)₂{η²-C(X)R}R′] (X = O or NTol-p); with [Zr(η-C₅H₅)₂{CH(SiMe₃)₂}Me] as substrate there is exclusive preference for scission of the more hindered ZrC bond.