New η-allyl η-cyclopentadienylcobalt cations

[Co(R-η-C₃H₄)(η-C₅H₅)I] is a good precursor for the preparation of some new cationic complexes as the iodide can easily be replaced; thus addition of PEt₃ to the iodo-complex (R  H) gives [Co(η-C₃H₅)(η-C₅H₅)(PEt₃)]⁺. The reactions of [Co(R-η-C₃H₄)(η-C₅H₅))I] (R  H or 2-Me) with AgBF₄ give solutions containing the coordinatively unsaturated species [Co(R-η-C₃H₄)(η-C₅H₅)⁺. The presence of traces of water leads to the formation of [Co(R-ηC₃H₄)-(η-C₅H₅)(H₂O)]⁺. The addition of monodentate ligands L  PEt₃ PPh₃, AsPh₃, SbPh₃, CNCH₃ and bidentate ligands LL  Ph₂PCH₂CH₂PPh₂(dppe) and o-C₆H₄(AsMe₂)₂(diars), gives, respectively mononuclear [Co(2-Me-ηC₃H₄)-(η-C₅H₅)L]⁺ and binuclear ligand-bridged [(2-Me-ηC₃H₄)(η-C₅H₅)CoLLCo(2-Me-ηC₃H₄)(η-C₅H₅))]²⁺ complexes. Crystals of [Co(2-Me-ηC₃H₄)(η-C₅H₅)-(H₂O)]⁺[BF₄]^- are monoclinic, space group P2₁/c, with a 7.858(3), b 10.262(4), c 15.078(4) Å, β 98.36(1)°. The molecular structure contains the cobalt atom bonded to planar 2-Me-allyl and cyclopentadienyl substituents, which are almost parallel with the H₂O molecule in a staggered conformation with respect to the 2-Me group.     

Complexes du titane et du zirconium contenant les ligands cyclopentadienyldiphenylphosphine et cyclopentadienylethyldiphenylphosphine: acces a des structures heterobimetalliques

Reactions of Ph₂P(CH₂)_n(C₅H₄)Li, (n = 0, 2), with MCl₄ or CpTiCl₃ (M = Ti, Zr; Cp = η⁵-C₅H₅) form Cl₂M[(η⁵-C₅H₄)(CH₂)_nPPh₂]₂ or Cl₂CpTi[(η⁵-C₅H₄)-(CH₂)₂PPh₂] in good yields. Chemical reduction with Al, or electrochemical reduction of these complexes, under CO, are described. The titanium(IV) and zirconium(IV) derivatives react with metal carbonyls (Mo(CO)₆, Cr(CO)₆, Fe(CO)₅, Mo(CO)₄(C₈H₁₂)) under formation of new heterobimetallic complexes. Reduction with Al of Cl₂CpTi[(η⁵-C₅H₄)(CH₂)₂PPh₂]Mo(CO)₅ under CO results in a new heterobimetallic species containing low valent titanium. Both complexes Cl₂M[(η⁵-C₅H₄)(CH₂)₂PPh₂]₂ (M = Ti, Zr) react with [Rh(μ-Cl)(CO)(C₂H₄)]₂ to yield {RhCl(CO)(Cl₂M[(η⁵-C₅H₄)(CH₂)₂PPh₂]₂)}x, which is assumed to be a dimer, in which the titanium or the zirconium compounds act as bridging diphosphine ligands between the rhodium atoms.     

Massenspektrometrische Untersuchungen an Organophosphorverbindungen. II—Elektronenstoßinduzierte Fragmentierungen von Tetraorganodiphosphandisulfiden

The behaviour under electron impact (70 eV) which includes some rearrangement processes of some tetraorganodiphosphanedisulfides R₂P(S)-P(S)R₂ (R ? CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, C₃H₅, C₆H₅) and CH₃RP(S)–P(S)CH₃R (R ? C₂H₅, n-C₃H₇, n-C₄H₉, C₆H₅, C₆H₅, C₆H₅,CH₂) is reported and discussed. Fragmentation patterns which are consistent with direct analysis of daughter ions and defocusing metastable spectra are given. The atomic composition of many of the fragment ions was determined by precise mass measurements. In contrast to compounds R₃P(S) loss of sulphur is not a common process here. The first step in the fragmentation of these compounds is cleavage of one P–C bond and loss of a substituent R?. The second step is elimination of RPS leading to [R₂PS]⁺ from which the base peaks in nearly all the spectra arise. The phenyl substituted compounds give spectra with very abundant [(C₆H₅)₃P]^+. and [(C₆H₅)₂CH₃P]^+. ions respectively, resulting from [M]^+. by migration of C₆H₅. Rearrangement of [M]^+. to a 4-membered P-S ring system prior to fragmentation is suggested.     

Diphenylcarbene rhodium complexes: of the halfsandwich type with (η5-C5H4SiMe3)Rh as a molecular unit

The square-planar rhodium(I) complexes trans-[RhCl(=CPh₂)(L)₂] (L = SbiPr₃, PiPr₃, PPh₃) react with LiC₅H₄SiMe₃ to give the halfsandwich type compounds [(η⁵-C₅H₄SiMe₃)Rh(=CPh₂)(L)] 7–9 in good to excellent yields. While the phosphine complexes 8 and 9 are rather inert toward Lewis bases, the stibine derivative 7 reacts with CO, CNtBu and PMe₃ to afford the corresponding substitution products [(η⁵-C₅H₄SiMe₃)Rh(=CPh₂)(L′] 10–12. In contrast, the reaction of 7 with C₂H₄ leads to the displacement of the carbene ligand and to the formation of the ethene complex [(η⁵-C₅H₄SiMe₃)Rh(C₂H₄)(SbiPr₃)] 14 together with the C−C coupling product Ph₂C=CHCH₃13. Upon treatment of 9 (L = PPh₃) with an equimolar amount of HCl, the chloro(hydrido)rhodium(III) compound [{η⁵-C₅H₃)(CHPH₂)(SiMe₃)}RhHCl(PPh₃)] 15 is formed. With an excess of HCl, a mixture of two products is obtained, one of which, with the composition [η⁵-C₅H₄)CHPh₂)RhCl₂(PPH₃)] 17 has been independently prepared from η⁵-C₅H₅)Rh(=CPh₂)(PPh₃] 18 and 2 equiv of HCl.     

Reactions of π-benzeneruthenium(II) complexes with alkylating reagents

The compounds (π-C₆H₆)Ru(R)Cl(PPh₃) (RCH₃, C₆H₅), (π-C₆H₆)RuCl(π-C₃H₅) and [(π-C₆H₆)Ru(π-C₅H₅)]Cl are described. The ³¹P NMR spectra of a series of tertiary phosphine complexes of the π-benzeneruthenium system are also reported.     

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.     

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.     

Metallorganische verbindungen des 1,2-diethinylbenzols vom typ o-C6H4(CCMR3)2 (M = Si,Ge, Pb)

The preparation of the compounds o-C₆H₄(CCMR₃)₂ (M = Si, Ge, Pb; R = CH₃; M = Pb; R = C₆H₅) is described. Their properties are compared with those of o-C₆H₄(CCSnR₃)₂ (R = CH₃, C₆H₅) and those of their p-isomers. The structures and bonding conditions proposed for these molecules are supported by dipole measurements, mass spectroscopy, IR, Raman, ¹H NMR and ¹³C NMR data.     

Cyclooctatetraenecyclopentadienyltitanium iodides

The synthesis and some of the properties of the new complexes (h⁸-C₈H₈)-(h⁵-C₅H₅)TiI and (h⁸-C₈H₈)(h⁵-C₅H₅)TiI₃ are described.     

Demercuriation reactions of the complexes [(PPh3)2RPtHgR′] containing platinum-mercury bonds

The compounds [(PPh₃)₂,RPtHgR′] (R = CH₃, R′= 2,5-C₆H₃Cl₂, 2,3,4- and 2,4,6-C₆H₂Cl₃, 2,3,4,5-, 2,3,4,6- and 2,3,5,6-C₆HCl₄, C₆Cl₅; R = Et, R′ = 2,5-C₆H₃Cl₂, 2,4,6-C₆H₂Cl₃; R = 2-C₆H₄Cl, R′=2-C₆H₄(CH₃)) have been prepared by the reactions of RHgR′ with Pt(PPh₃)₃, in order to study their possible use as intermediates in the preparation of diorganoplatinum complexes with different organic ligands. The dependence of J(³¹P-¹⁹⁵Pt) on slight differences in the electronic character of the ligand R′ in the series of compounds [(PPh₃)₂(CH₃)Pt-HgR′] has been studied.     

Irregular cyclization reactions in titanocenes bearing pendant double bonds

Reduction of methyl-substituted titanocene dichlorides bearing pendant double bonds [TiCl₂{η⁵-C₅Me₄(CH₂CMeCH₂)}₂] (1) and [TiCl₂{η⁵-C₅Me₄(SiMe₂(CH₂)₂CHCH₂)}₂] (2) with magnesium yielded diamagnetic Ti(IV) compound [Ti{η¹:η¹:η⁵-C₅Me₃(CH₂)(CH₂CH(Me)CH₂)}{η⁵-C₅Me₄(CH₂C(Me)CH₂)}] (4) and paramagnetic Ti(III) compound [Ti{η⁵-C₅Me₄(SiMe₂CH₂CHCHMe)}(μ-η³,η¹:η⁵,η¹(Ti:Mg){C₅Me₃(CH₂)(SiMe₂CHCHCMe)})Mg(OC₄H₈)₂] (6), respectively. The reluctance of titanocene intermediates to undergo intramolecular cyclization to cyclopentadienyl-ring-tethered titanacycles (as typically observed) can be explained by a shortness of the 2-methylallyl group and steric hindrance of its double bond in the former case and, in the latter case, by an attack of magnesium on the titanocene intermediate, faster than cyclization reactions. The crystal structures of 4 and 6 were determined by single-crystal X-ray diffraction.     

Stilbene analogues incorporating the Co(η-C4Ph4)(η-C5H4-) end group

A number of organometallic stilbenes of the general type [Co(η⁴-C₄Ph₄)(η⁵-C₅H₄CHCHR] are reported where R is C₆H₄X-4 (X = H, OMe, Br, NO₂), 1-naphthyl, 9-anthryl, 1-pyrenyl, (η⁵-C₅H₄)Co(η⁴-C₄Ph₄), and (η⁵-C₅H₄)Fe(η⁵-C₅H₄Y) {Y = CHO, CHC(CN)₂ and CHCHC₅H₄-η⁵)Co(η⁴-C₄Ph₄)}. They were prepared by Wittig or Horner-Wadsworth-Emmons reactions which yield both E and Z or only E products respectively. The isomers were separated and all compounds characterised by standard spectroscopic techniques as well as by X-ray diffraction methods in many cases. The electrochemistry of the stilbene analogues in dichloromethane solution is also reported. In most, the (η⁵-C₅H₄)Co(η⁴-C₄Ph₄) functional group undergoes a reversible one-electron oxidation. For those molecules that also include (η⁵-C₅H₄)Fe(η⁵-C₅H₄Y), this is preceded by the reversible oxidation of the ferrocenyl group. Spectroscopic and structural data suggests that for most compounds there is little electronic interaction between Co(η⁴-C₄Ph₄)(η⁵-C₅H₄) and the R end groups which are effectively independent of one another. The only exceptions to this are Z and E-[Co(η⁴-C₄Ph₄)(η⁵-C₅H₄CHCHC₆H₄NO₂-4], and [Co(η⁴-C₄Ph₄)(η⁵-C₅H₄CHCHC₅H₄-η⁵)Fe{η⁵-C₅H₄CHC(CN)₂}] where the electronic spectra are respectively consistent with a significant Co(η⁴-C₄Ph₄)(η⁵-C₅H₄)/NO₂ donor/acceptor interaction and a less significant Co(η⁴-C₄Ph₄)(η⁵-C₅H₄)/C(CN)₂ one. However, OTTLE studies show that in the electronic spectra of [Co(η⁴-C₄Ph₄)(η⁵-C₅H₄CHCHR]⁺ there are low energy absorption bands (950-1800 nm) which are attributed to R → Co(η⁴-C₄Ph₄)(η⁵-C₅H₄)⁺ or, when R is a ferrocenyl-base group, Co(η⁴-C₄Ph₄)(η⁵-C₅H₄) → (η⁵-C₅H₄)Fe(η⁵-C₅H₄Y)⁺ charge transfer transitions. The ferrocenyl compounds undergo cis/trans isomerisation on the OTTLE experiment timescale.     

Syntheses and characterization of new palladium(II) complexes with functionally substituted cyclopentadienyl groups

Thallium [1-(p-tolylimino)-2-methylpropyl]cyclopentadienide, Tl[C₅H₄C(=NC₆H₄CH₃)CH(CH₃)₂], was prepared and treatment of the salt with [{PdCl₂(PREt₂)}₂] (R = Ph and Et) yielded mononuclear palladium(II) complexes, [Pd{η⁵-C₅H₄C(=NC₆H₄CH₃)CH(CH₃)₂}Cl(PREt₂)], with an imidoyl-substituted η⁵-cyclopentadienyl group. In addition, [Pd(η⁵-C₅H₄-COY)Cl(PPhEt₂)] (Y = CH₃ and OCH₃) complexes were obtained from the sodium salts of their substituted cyclopentadienyl groups. These new compounds were characterized by means of ¹H and ¹³C NMR and IR spectroscopy.     

Optically active transition-metal compounds: XXII. Stereochemistry and crystal structure determination of (η5-C5H5)CoI(NC4H3C(R)=N(S)-CH(CH3)(C6H5)) (R = H,CH3)

The crystal structures and absolute configurations of (η⁵-C₅H₅)-CoI(NC₄H₃-C(R)=N(S)-CH(CH₃)(C₆H₅)) (R = H, compound I; R = CH₃, compound II) have been determined by single crystal X-ray diffraction. Crystals of compound I are orthorhombic, with a 11.084(6), b 12.107(6) and c 13.121(7) Å, space group ^P2₁2₁2₁ and d (calcd, Z = 4) 1.69 g cm^?3 The structure was solved by the Patterson technique and refined with use of full matrix least-squares methods to R(F) = 0.031 and R_w(F) = 0.028. Compound II is nearly isomorphous and isostructural; a 11.246(6), b 11.923(6) and c 13.370(7) Å, d(calc., Z = 4) 1.71 g cm^?3 and was refined to the final agreement factors of R(F) = 0.044 and R_w(F) = 0.035. The Co atom has a distorted tetrahedral coordination, with Co-I 2.595(2) for I and 2.607(2) Å for II; Co-(η⁵-C₅H₅ ring centroid) 1.681(4) and 1.703(5) Å; Co-N(pyrrole) 1.905(9) and 1.885(9) Å; Co-N(imine) 1.971(8) and 2.003(9) Å, all the parameters being well within values found in the literature. The configuration around the chiral carbon of the phenylethylamine is S for both compounds, whereas the configuration around the metal is R in I and S in II. The different metal configurations in I and II have their origin in the two different substituents (R = H, CH₃) at the imine carbon atoms of the chelate ring, which induce completely different conformations of the (S)-CH(CH₃)(C₆H₅) moiety in the two complexes. For both compounds the thermodynamically less stable isomer is enriched upon crystallization. Also, for compound I the solution and solid state conformations are almost opposite to each other, the conformation in the solid reflecting intramolecular interactions (phenyl/C₅H₅ attraction).     

Exploratory organometal-sulfur chemistry; syntheses and unusual properties of rhenium CH2SR,CHSRR′, and CHSR]+ complexes

The methylidene complex [(η-C₅H₅)Re(NO)(PPh₃)(CH₂)]⁺PF₆^?(I) yields kinetically labile sulfonium salts when treated with CH₃SCH₃, CH₃SCH₂C₆H₅, and (η-C₅H₅)Re(NO)(PPh₃)(CH₂SCH₃) (V);the binuclear adduct formed in the latter case, [(η-C₅H₅)Re(NO)(PPh₃)CH₂]₂S⁺CH₃ (VI), is substantially more stable than the others and undergoes hydride transfer disproportionation to [(η-C₅H₅)Re(NO)(PPh₃)(CHSCH₃)]⁺PF₆^?(VII) and (η-C₅H₅)Re(NO)(PPh₃)(CH₃) (VIII) when heated.     

Trinuclear π-cyclopentadienyl bridging sulphido derivatives of iron

The reaction of [Fe(π-C₅H₅)(CO)₂]₂ with the dialkyl disulphides R₂S₂ (R = CH₃, C₂H₅, t-C₄H₉ or CH₂C₆H₅) affords, as well as dinuclear derivatives of the type [Fe(π-C₅H₅)(CO)SR]₂, trinuclear species of formula [Fe₃(π-C₅H₅)₃(CO)₂(S)SR].     

Darstellung und eigenschaften von und reaktionen mit metallhaltigen heterocyclen XXII. Synthese, eigenschaften und kristallstruktur des sechsgliedrigen heterocyclus [(h-C5H5)NiSP(CH3)2]2 und dessen verhalten gegenüber alkinen

The heterocycle [(h⁵-C₅H₅)NiSP(CH₃)₂]₂ is obtained by treatment of (h⁵-C₅H₅)₂Ni with (CH₃)₂HPS in toluene and crystallizes monoclinic in the space group P2₁/c with Z = 2. The highly reactive three-membered ring (h⁵-C₅H₅)$\text{NiSP}$(CH₃)₂ which is a dissociation product of [(h⁵-C₅H₅)NiSP(CH₃)₂]₂, can be trapped with bis(methoxycarbonyl)acetylene to give the PS containing nickelacyclopentadiene (h⁵-C₅H₅)$\text{NiSP(CH}{}_3\text{)}{}_2\text{CRC}$R (R  CO₂CH₃).     

Triorganoantimon- und Triorganobismutderivate von Carbonsäuren fünfgliedriger Heterocyclen Kristall- und Molekülstruktur von (C6H5)3Sb(O2C-2-C4H3S)2

Inhaltsübersicht. Triorganoantimon- und Triorganobismutdicarboxylate R₃M[O₂C(CH₂)ⁿ-2-C₄H₃X]₂ (M = Sb, R = CH₃, C₆H₁₁, C₆H₅, 4-CH₃OC₆H₄; M = Bi, R = C₆H₅, 4-CH₃C₆H₄; n = 0, X = O, S, NH, NCH₃. M = Sb, R = CH₃, C₆H₅; M = Bi, R = C₆H₅; n = 1, X = O, S. M = Sb, R = C₆H₁₁, n = 1, X = S; R = 4-FC₆H₄, n = 0, X = O, S, NCH₃; R = 2,4,6-(CH₃)₃C₆H₂, n = 0, X = O, S, NH) wurden durch Reaktionen von R₃Sb(OH)₂ (R = CH₃, C₆H₁₁, 2,4,6-(CH₃)₃C₆H₂), R₃SbO (R = C₆H₅, 4-CH₃OC₆H₄, 4-FC₆H₄) bzw. R₃BiCO₃ mit den entsprechenden fünfgliedrigen heterocyclischen Carbonsäuren 2-C₄H₃X(CH₂)_nCOOH dargestellt. Auf der Basis schwingungsspektroskopischer Daten wird für alle Verbindungen eine trigonal bipyramidale Umgebung vom M (zwei O-Atome von einzähnigen Carboxylatliganden in den apikalen, drei C-Atome von R in den äquatorialen Positionen) vorgeschlagen, ferner eine schwache Wechselwirkung zwischen O(=C) jeder Carboxylatgruppe und M. Die Kristallstrukturbestimmung von (C₆H₅)₃Sb(O₂C–2-C₄H₃S)₃ stützt diesen Vorschlag. Die Verbindung kristallisiert triklin [Raumgruppe P$1; a = 891,8(14), b = 1058,2(12), c = 1435,6(9) pm, α = 68,53(8), β = 85,47(9), γ = 85,99(11)°; Z = 2; d(ber.) = 1,607 Mg m^–3; V(Zelle) = 1255,6 ų; Strukturbestimmung anhand von 3947 unabhängigen Reflexen (F_o > 3σ(F²_o)), R(ungewichtet) = 0,037]. Sb bindet drei C₆H₅-Gruppen in der äquatorialen Ebene [mittlerer Abstand Sb–C: 211,1(5)pm] und zwei einzähnige Carboxylatliganden in den apikalen Positionen einer verzerrten trigonalen Bipyramide [mittlerer Abstand Sb–O: 212,0(4) pm]. Aus den relativ kurzen Sb – O(=C)-Abständen [274,4(4) und 294,9(4) pm] und aus der Aufweitung des dem O(=C)-Atom nächsten äquatorialen C–Sb–C-Winkels auf 145,9(2)° [andere C-Sb-C-Winkel: 104,4(2), 109,5(2)°] wird auf schwache Sb–O(=C)-Koordination geschlossen. Schließlich wird eine Korrelation zwischen dem (+, –)I-Effekt des Organoliganden R an M (M = Sb, Bi) und der Stärke der M–O(=C)-Koordination in den Dicarboxylaten R₃M[O₂C(CH₂)_n–2-C₄H₃X]₂ vorgeschlagen. Triorganoanümony and Triorganobismuth Derivatives of Carbonic Acids of Five-membered Heterocycles. Crystal and Molecular Structure of (C₆H₅)₃Sb(O₂C–2-C₄H₃S)₂ Triorganoantimony- and triorganobismuth dicarboxylates R₃M[O₂C(CH₂)_n–2-C₄H₃X]₂ (M = Sb, R = CH₃, C₆H₁₁, C₆H₅, 4-CH₃OC₆H₄; M = Bi, R = C₆H₅, 4-CH₃C₆H₄; n = 0, X = O, S, NH, NCH₃. M = Sb, R = CH₃, C₆H₅; M = Bi, R = C₆H₅; n = 1, X = O, S. M = Sb, R = C₆H₁₁, n = 1, X = S; R = 4-FC₆H₄, n = 0, X = O, S, NCH₃; R = 2,4,6-(CH₃)₃C₆H₂, n = 0, X = O, S, NH) have been prepared by reaction of R₃Sb(OH)₂ (R = CH₃, C₆H₁₁; 2,4,6-(CH₃)₃C₆H₂), R₃SbO (R = C₆H₅, 4-CH₃OC₆H₄, 4-FC₆H₄) or R₃BiCO₃ with the appropriate five-membered heterocyclic carboxylic acid. From vibrational data for all compounds a trigonal bipyramidal environment around M (two O atoms of unidendate carboxylate ligands in apical, three C atoms (of R) in equatorial positions) is proposed and also an additional weak interaction of O(=C) of each carboxylate group and M. The crystal structure determination of Ph₃Sb(O₂C–2-C₄H₃S)₂ gives additional prove to this proposal. It crystallizes triclinic [space group P$1; a = 891.8(14), b = 1058.2(12), c = 1435.6(9) pm, α = 68.53(8), β = 85.47(9), γ = 85.99(11)°; Z = 2; d(calc.) = 1.607 Mg m^–3; V_cell = 1255.6 ų; structure determination from 3 947 independent reflexions (F_o > 3σ(F²_o)), R(unweighted) = 0.037]. Sb is bonding to three C₆H₅ groups in the equatorial plane [mean distance Sb–C: 211.1(5) pm] and two unidentate carboxylate ligands in the apical positions of a distorted trigonal bipyramid [mean distance Sb–O: 212.0(4) pm]. From the relatively short Sb–O(=C) distances [274.4(4) and 294.9(4) pm] and from the enlarged value of the equatorial C–Sb–C angle next to the O(=C) atom [145.9(2)°; other C–Sb–C angles: 104.4(2), 109.5(2)°] additional weak Sb–O(=C) coordination is inferred. Finally a correlation between the (+, –) I-effect of the organic ligands It at M and the strength of the M–O = C interaction is suggested.     

Photochemical studies on η5-cyclopentadienyl(triphenylphosphine)nickelalkyl and -aryl compounds

Photo-induced degradation studies of a series of organonickel complexes of the type (η⁵-C₅H₅)(PPh₃)Ni(R) (R = CH₃, C₂H₅, C₆H₅ and C₆H₄CH₃-p) as well as certain deuterated analogs have been undertaken. Photolysis of the methyl compounds in benzene as well as benzene-d₆ gives methane as the major gaseous product, the photogenerated methyl group abstracting hydrogen from either the cyclopentadienyl ring, from the solvent, or from another methyl group. The photo-induced dealkylation of the ethyl compound gives both ethylene and ethane, and is explained by β-hydride elimination followed by subsequent reaction of the hydrido intermediate with additional ethyl compound. The photolysis of the phenyl and p-tolyl complexes in benzene solution leads to biaryl formation, both from the coupling of two coordinated aryl groups as well as interactions with the solvent. Triphenylphosphine is a product in all of these photo-decomposition studies.     

NMR investigation of bis(2,3-alkanedione dioximato)-bis(pyridine)cobalt(III) iodide complexes: 1H and 13C NMR spectra and 13C spin-lattice relaxation time measurements

The complexes of trans-[Co(III)(R,CH₃-dioxH)₂(py)₂]I2 (R = CH₃, C₂H₅, n-C₃H₇ and n-C₄H₉) were investigated in solution by ¹H and ¹³C NMR spectra and ¹³C spin-lattice relaxation time measurements. The ¹H and ¹³C-resonances of the R = C₂H₅, n-C₃H₇ and n-C₄H₉) groups were shifted to higher field than those of the free ligands by the complexation; it was attributable to the ring current shielding due to the axial pyridine ligands of the complexes. ¹³C spin-lattice relaxation times were interpreted as due to movement of the axial pyridine ligands as if they twist around the CoN (pyridine nitrogen) bond axis and the above R groups were moving segmentally. These segmental movements allowed the R groups to approach closely toward the axial pyridine ring plane to experience the ring current shielding.