Synthesis of octahedral carbonyl complexes of manganese(I) with SCN or CN ligands. Crystal structure of fac-[SCNMn(CO)3(dppm)]

The complexes fac-[XMn(CO)₃(dppm)], cis,cis-[XMn(CO)₂(dppm)(P(OPh)₃)] and trans-[XMn(CO)(dppm)₂] with X = SCN or CN have been prepared from the corresponding bromocarbonyls and the salts AgX or KX, or, in the case of the di- and mono-carbonyls, from fac-[XMn(CO)₃(dppm)] with X = SCN or CN by thermal or photochemical CO substitution by the ligands P(OPh)₃ or dppm. The structure of fac-[SCNMn(CO)₃(dppm)] has been determined by X-ray diffraction. The crystals are monoclinic, space group P2₁/n, and the structure has been refined to R = 0.058 for 4123 reflexions measured in the range 2 ⩽ θ ⩽ 30 at room temperature. The cis,cis-[NCMn(CO)₂(dppm)(P(OPh)₃)] complex can be oxidized and subsequently reduced to the isomer trans-[NCMn(CO)₂(dppm)(P(OPh)₃)]. All the neutral cyanide complexes react readily with MeI and KPF₆ to give the corresponding methylisocyanide derivatives [Mn(CO)₂(dppm)(P(OPh)₃)(CNMe)]PF₆ and [Mn(CO)(dppm)₂(CNMe)]PF₆. The stereochemistries of the compounds is discussed in relation to the ³¹P NMR spectra.     

Synthesis and spectra of bis(tertiaryphosphine) derivatives of cycloheptatrienyltungsten complexes

Reaction of [WI(CO)₂(η⁷-C₇H₇)] with dppm (dppm = Ph₂PCH₂PPh₂) or dppe (dppe = Ph₂PCH₂CH₂PPh₂) gives the trihaptocycloheptatrienyl complexes [WI(CO)₂(L-L)(η³-C₇H₇)] [L-L = dppm, (A₁); L-L = dppe (A₂)]. The complex A₁ reacts with NH₄PF₆ to give the unidentate biphosphine complex [W(CO)₂(dppm-P)(η⁷-C₇H₇)][PF₆] (B) which yields [W(CO)(dppm)(η⁷-C₇H₇)][PF₆] (C) on reaction with Me₃NO·2H₂O. Substitution of a carbonyl ligand in [W(CO)₃(η⁷-C₇H₇)][PF₆] with the organometallic phosphine ligand [Mo(CO)₂(dppe-P)(η⁷-C₇H₇)][PF₆] yields the heterobimetallic [{W(CO)₂(η⁷-C₇H₇)}(μ-dppe){Mo(CO)₂(η⁷-C₇H₇)}x][PF₆]₂ (D).     

Schwefelmonoxid-komplexe: III. Ein kationischer eisen-so-komplex

The compounds [cpFe(dppe)(SO)]PF₆, the first mononuclear cationic complex of sulfur monoxide, and [cpFe(dppe)(SO₂)]PF₆ were obtained in high yield from the corresponding carbonyl [cpFe(dppe)(CO)]PF₆. From spectroscopic studies the sulfur monoxide was found to be coordinated to iron in the usual bent η¹-fashion; the sulfur dioxide complex, as expected, contains SO₂ in an η¹-planar fashion.     

[Fe2(μsb‐CO)(CO)3(NO)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)]: Synthese,Kristallstruktur und Koordinationsisomerie

[Fe₂(μ_sb‐CO)(CO)₃(NO)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)]: Synthesis, X‐ray Crystal Structure and Isomerization Na[Fe₂(μ‐CO)(CO)₆(μ‐P^tBu₂)] ( 1 ) reacts with [NO][BF₄] at —60 °C in THF to the nitrosyl complex [Fe₂(CO)₆(NO)(μ‐P^tBu₂)] ( 2 ). The subsequent reaction of 2 with phosphanes (L) under mild conditions affords the complexes [Fe₂(CO)₅(NO)L(μ‐P^tBu₂)], L = PPh₃, ( 3a ); η‐dppm (dppm = Ph₂PCH₂PPh₂), ( 3b ). In this case the phosphane substitutes one carbonyl ligand at the iron tetracarbonyl fragment in 2 , which was confirmed by the X‐ray crystal structure analysis of 3a . In solution 3b loses one CO ligand very easily to give dppm as bridging ligand on the Fe‐Fe bond. The thus formed compound [Fe₂(CO)₄(NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4 ) occurs in solution in different solvents and over a wide temperature range as a mixture of the two isomers [Fe₂(μ_sb‐CO)(CO)₃(NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4a ) and [Fe₂(CO)₄(μ‐NO)(μ‐P^tBu₂)(μ‐dppm)] ( 4b ). 4a was unambiguously characterized by single‐crystal X‐ray structure analysis while 4b was confirmed both by NMR investigations in solution as well as by means of DFT calculations. Furthermore, the spontaneous reaction of [Fe₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 5 ) with NO at —60 °C in toluene yields a complicated mixture of products containing [Fe₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 6 ) as main product beside the isomers 4a and 4b occuring in very low yields.     

Crystallographic report: Crystal structures of organometallic aqua complexes [Cp*RhIII(bpy)(OH2)]2+ and [Cp*RhIII(6,6′‐Me2bpy)(OH2)]2+ used as key catalysts in regioselective reduction of NAD+ analogues

Crystal structures of organometallic aqua complexes [Cp*Rh^III(bpy)(OH₂)]²⁺ ( 1 , Cp* = η⁵‐C₅Me₅, bpy = 2,2′‐bipyridine) and [Cp*Rh^III(6,6′‐Me₂bpy)(OH₂)]²⁺ ( 2 , 6,6′‐Me₂bpy = 6,6′‐dimethyl‐2,2′‐bipyridine) used as key catalysts in regioselective reduction of NAD⁺ analogues were determined definitely by X‐ray analysis. The yellow crystals of 1 (PF₆)₂ and orange crystals of 2 (CF₃SO₃)₂ used in the X‐ray analysis were obtained from aqueous solutions of 1 (PF₆)₂ and 2 (CF₃SO₃)₂. The Rh–O_aqua length of 2.194(4) Å obtained for 1 (PF₆)₂ is significantly different from that of 2.157(3) Å obtained for the previously reported disorder model [Cp*Rh^III(bpy)(0.7H₂O/0.3CH₃OH)](CF₃SO₃)₂·0.7H₂O in which the coordinated water is replaced by a coordinated methanol. The five‐membered ring involving the Rh atom and the 6,6′‐Me₂bpy chelating unit in 2 (CF₃SO₃)₂ is not flat, whereas the five‐membered chelate ring in 1 (PF₆)₂ is nearly flat. Such a non‐planar structure in 2 (CF₃SO₃)₂ is ascribed to the steric repulsion between the 6,6′‐Me₂bpy ligand and the Cp* ligand. Copyright © 2005 John Wiley & Sons, Ltd.     

Koordinativ ungesättigte Dieisenkomplexe: Synthese und Kristallstrukturen von [Fe2(CO)4(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] und [Fe2(CO)4(μ‐CH2)(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)]

Coordinatively Unsaturated Diiron Complexes: Synthesis and Crystal Structures of [Fe₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] and [Fe₂(CO)₄(μ‐CH₂)(μ‐H)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] [Fe₂(μ‐CO)(CO)₆(μ‐H)(μ‐P^tBu₂)] ( 1 ) reacts spontaneously with dppm (dppm = Ph₂PCH₂PPh₂) to give [Fe₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 2 c ). By thermolysis or photolysis, 2 c loses very easily one carbonyl ligand and yields the corresponding electronically and coordinatively unsaturated complex [Fe₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 3 ). 3 exhibits a Fe–Fe double bond which could be confirmed by the addition of methylene to the corresponding dimetallacyclopropane [Fe₂(CO)₄(μ‐CH₂)(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 4 ). The reaction of 1 with dppe (Ph₂PC₂H₄PPh₂) affords [Fe₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppe)] ( 5 ). In contrast to the thermolysis of 2 c , yielding 3 , the heating of 5 in toluene leads rapidly to complete decomposition. The reaction of 1 with PPh₃ yields [Fe₂(CO)₆(H)(μ‐P^tBu₂)(PPh₃)] ( 6 a ), while with ^tBu₂PH the compound [Fe₂(μ‐CO)(CO)₅(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] ( 6 b ) is formed. The thermolysis of 6 b affords [Fe₂(CO)₅(μ‐P^tBu₂)₂] and the degradation products [Fe(CO)₃(^tBu₂PH)₂] and [Fe(CO)₄(^tBu₂PH)]. The molecular structures of 3 , 4 and 6 b were determined by X‐ray crystal structure analyses.     

Koordinativ ungesättigte Dirutheniumkomplexe: Synthese und Kristallstrukturen von [Ru2(CO)n(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] (n = 4; 5) und [Ru2(CO)4(μ‐CH2)(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)]

Coordinatively Unsaturated Diruthenium Complexes: Synthesis and X‐ray Crystal Structures of [Ru₂(CO)_n(μ‐H)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] (n = 4; 5) and [Ru₂(CO)₄(μ‐CH₂)(μ‐H)(μ‐P^tBu₂)(μ‐Ph₂PCH₂PPh₂)] The reaction of [Ru₂(μ‐CO)(CO)₅(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)] ( 2 ) with dppm yields the dinuclear species [Ru₂(μ‐CO)(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 3 ) (dppm = Ph₂PCH₂PPh₂). Under thermal or photolytic conditions 3 loses very easily one carbonyl ligand and affords the corresponding electronically and coordinatively unsaturated complex [Ru₂(CO)₄(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 4 ). 4 is also obtainable by an one‐pot synthesis from [Ru₃(CO)₁₂], an excess of ^tBu₂PH and stoichiometric amounts of dppm via the formation of [Ru₂(CO)₄(μ‐H)(μ‐P^tBu₂)(^tBu₂PH)₂] ( 1 ). 4 exhibits a Ru–Ru double bond which could be confirmed by addition of methylene to the dimetallacyclopropane [Ru₂(CO)₄(μ‐CH₂)(μ‐H)(μ‐P^tBu₂)(μ‐dppm)] ( 5 ). The molecular structures of 3 , 4 and 5 were determined by X‐ray crystal structure analyses.     

Synthesis and Structures of d10–d10 M2(μ‐dppm)2 Complexes with Sensitive Metal–Metal Distances in Response to the Binding of Sigma Donors

Diphosphine‐bridged dicopper(I) acetate complexes [Cu₂(μ‐dppm)₂(μ‐OAc)]X ( 2 X; X^? = , ) and [Cu₂(μ‐dppm)₂(μ‐OAc)(MeCN)]X ( 4 X) were prepared and the structures of 2 (PF₆ ) and 4 (PF₆ ) determined by X‐ray crystallography. The ground‐state geometries of [Cu₂(μ‐dppm)₂(μ‐OAc)]⁺ and [Cu₂(μ‐dppm)₂(μ‐OAc)(L)]⁺ (L = py, MeCN, THF, acetone, MeOH) were also obtained using density functional theory (DFT). The increased Cu – Cu distances found experimentally and theoretically by comparing the structures of cation [Cu₂(μ‐dppm)₂(μ‐OAc)]⁺ and its derivatives [Cu₂(μ‐dppm)₂(μ‐OAc)(L)]⁺ reflect the binding of various sigma donors (L). When using [Cu₂(μ‐dppm)₂(μ‐OAc)]⁺ as a structure sensor, the electron‐donating strength of a sigma donor can be quantitatively expressed as a DFT‐calculated Cu – Cu distance with the relative strength in the order py > MeCN > THF > acetone > MeOH, as determined.     

Synthesis and spectroscopy of cis-configured mononuclear palladium(II) and platinum(II) complexes of chalcogeno o-carboranes and structures of [Pt(SCboPh)2(dppm)], [Pt(SeCboPh)2(dppm)], [Pt(SCboS)(PMe2Ph)2] and [Pt(SCboS)(PMePh2)2]

The reactions of [MCl₂(P^∩P)] and [MCl₂(PR₃)₂)] with 1-mercapto-2-phenyl-o-carborane/NaSeCb^oPh and 1,2-dimercapto-o-carborane yield mononuclear complexes of composition, [M(SCb^oPh)₂(P^∩P)], [M(SeCb^oPh)₂(P^∩P)] (M = Pd or Pt; P^∩P = dppm (bis(diphenylphosphino)methane), dppe (1,2-bis(diphenylphosphino)ethane) or dppp (1,3-bis(diphenylphosphino)propane)) and [M(SCb^oS)(PR₃)₂] (2PR₃ = dppm, dppe, 2PEt₃, 2PMe₂Ph, 2PMePh₂ or 2PPh₃). These complexes have been characterized by elemental analysis and NMR (¹H, ³¹P, ⁷⁷Se and ¹⁹⁵Pt) spectroscopy. The ¹J(Pt–P) values and ¹⁹⁵Pt NMR chemical shifts are influenced by the nature of phosphine as well as thiolate ligand. Molecular structures of [Pt(SCb^oPh)₂(dppm)], [Pt(SeCb^oPh)₂(dppm)], [Pt(SCb^oS)(PMe₂Ph)₂] and [Pt(SCb^oS)(PMePh₂)₂] have been established by single crystal X-ray structural analyses. The platinum atom in all these complexes acquires a distorted square planar configuration defined by two cis-bound phosphine ligands and two chalcogenolate groups. The carborane rings are mutually anti in [Pt(SCb^oPh)₂(dppm)] and [Pt(SeCb^oPh)₂(dppm)].     

Neutral and cationic dicarbonyl complexes of manganese (I) with diphosphines

The reaction of BrMn(CO)₅ with dppm in refluxing toluene gives the neutral compunds cis-cis-BrMn(CO)₂(dppm)₂ which has been shown by ³¹P NMR spectroscopy to have one dppm monodentate and the other bidendate. This complex reacts with TIPF₆ in dichloromethane solution to give the salt cis-[Mn(CO)₂-(dppm)₂]PF₆ or, if the reaction is carried out in the presence of CO, the salt mer-[Mn(CO)₃(dppm)₂]PF₆ which also has one monodentate dppm (by ³¹P NMR). The cationic complex cis-[Mn(CO)₂(dppm)₂]⁺ isomerizes to the transisomer when irradiated with UV light, while heating of the latter gives back the cis-isomer. The perchlorate salts of the cation cis-[Mn(CO)₂(dppm)₂⁺ can be prepared by reacting fac-O₃ClOMn(CO)₃(dppm) withdppm in refluxing toluene, and trans-[Mn(CO)₂(diphos)(diphos)′]⁺, diphos or diphos′ being dppm or dppe, by treating the fac-O₃ClMn(CO)₃(diphos) with dppm or dppe under UV irradiation.     

Synthesis,Reactivity, and Crystal Structure of the η2‐Thiocarbamoyl Palladium Complex [Pd(PPh3)2(η2‐SCNMe2)][PF6]

The η¹‐thiocarbamoyl palladium complexes [Pd(PPh₃)(η¹‐SCNMe₂)(η²‐S₂R)] (R = P(OEt)₂, 2 ; CNEt₂, 3 ) and trans‐[Pd(PPh₃)₂(η¹‐SCNMe₂)(η¹‐Spy)], 4 , (pyS: pyridine‐2‐thionate) are prepared by reacting the η²‐thiocarbamoyl palladium complex [Pd(PPh₃)₂(η²‐SCNMe₂)][PF₆], 1 with (EtO)₂PS₂NH₄, Et₂NCS₂Na, and pySK in methanol at room temperature, respectively. Treatment of 1 with dppm (dppm: bis(diphenylphosphino)methane) in dichloromethane at room temperature gives complex [Pd(PPh₃)(η¹‐SCNMe₂)(η²‐dppm)] [PF₆], 5 . All of the complexes are identified by spectroscopic methods and complex 1 is determined by single‐crystal X‐ray diffraction.     

Electrochemistry and Spectroscopy of Sulfate Complexes of (Tetraphenylporphyrinato)manganese

The electrochemical and spectroscopic properties of [Mn₂(tpp)₂(SO₄)] (H₂tpp=tetraphenylporphyrin=5,10,15,20‐tetraphenyl‐21H,23H‐porphine) were studied to characterize the stability of this compound as a function of solvent, redox state, and sulfate concentration. In non‐coordinating solvents such as 1,2‐dichloroethane, the dimer was stable, and two cyclic voltammetric waves were observed in the region for Mn^III reduction. These waves correspond to reduction of the dimer to [Mn^II(tpp)] and [Mn^III(tpp)(OSO₃)]^?, and reduction of [Mn^III(tpp)(OSO₃)]^? to [Mn^II(tpp)(OSO₃)]^2?, respectively. In the coordinating solvent DMSO, [Mn₂(tpp)₂(SO₄)] was unstable and dissociated to form [Mn^III(tpp)(DMSO)₂]⁺. A single voltammetric wave was observed for Mn^III reduction in this solvent, corresponding to formation of [Mn^II(tpp)(DMSO)]. In non‐coordinating solvent systems, addition of sulfate (as the bis(triphenylphosphoranylidene)ammonium (PPN⁺) salt) resulted in dimer dissociation, yielding [Mn^III(tpp)(OSO₃)]^?. Reduction of this monomer produced [Mn^II(tpp)(OSO₃)]^2?. In DMSO, addition of SO led to displacement of solvent molecules forming [Mn^III(tpp)(OSO₃)]^?. Reduction of this species in DMSO led to [Mn^II(tpp)(DMSO)].     

Synthesis and spectroscopy of cis-configured mononuclear palladium(II) and platinum(II) complexes of chalcogeno o-carboranes and structures of [Pt(SCboPh)2(dppm)], [Pt(SeCboPh)2(dppm)], [Pt(SCboS)(PMe2Ph)2] and [Pt(SCboS)(PMePh2)2]

The reactions of [MCl₂(P^∩P)] and [MCl₂(PR₃)₂)] with 1-mercapto-2-phenyl-o-carborane/NaSeCb^oPh and 1,2-dimercapto-o-carborane yield mononuclear complexes of composition, [M(SCb^oPh)₂(P^∩P)], [M(SeCb^oPh)₂(P^∩P)] (M = Pd or Pt; P^∩P = dppm (bis(diphenylphosphino)methane), dppe (1,2-bis(diphenylphosphino)ethane) or dppp (1,3-bis(diphenylphosphino)propane)) and [M(SCb^oS)(PR₃)₂] (2PR₃ = dppm, dppe, 2PEt₃, 2PMe₂Ph, 2PMePh₂ or 2PPh₃). These complexes have been characterized by elemental analysis and NMR (¹H, ³¹P, ⁷⁷Se and ¹⁹⁵Pt) spectroscopy. The ¹J(Pt–P) values and ¹⁹⁵Pt NMR chemical shifts are influenced by the nature of phosphine as well as thiolate ligand. Molecular structures of [Pt(SCb^oPh)₂(dppm)], [Pt(SeCb^oPh)₂(dppm)], [Pt(SCb^oS)(PMe₂Ph)₂] and [Pt(SCb^oS)(PMePh₂)₂] have been established by single crystal X-ray structural analyses. The platinum atom in all these complexes acquires a distorted square planar configuration defined by two cis-bound phosphine ligands and two chalcogenolate groups. The carborane rings are mutually anti in [Pt(SCb^oPh)₂(dppm)] and [Pt(SeCb^oPh)₂(dppm)].     

Cluster chemistry: XXIX. Preparation of cluster complexes containing aryldiazo ligands: Crystal structure of [HRu3(μ-N2C6H4)(μ3-PhAsCH2AsPh2)(CO)8]

Hydrogenation of [Ru₃(CO)₁₀(L₂)] (L₂ = dppm or dpam) affords [HRu₃(μ₃-PhECH₂EPh₂)(CO)₉] (E = P or As), which is deprotonated by K[HBBu₃^s] . Reactions of the anions with [PhN₂] [PF₆] give [Ru₃(μ-N₂Ph)(μ₃-PhECH₂EPh₂)(CO)₉], which undergo facile cyclometallation reactions when heated, as revealed by an X-ray structure of the title complex.     

Emissive Annular Digold(I) Compounds Containing Diphosphine and Dithiolate Ligands

Molecular structures of three emissive annular digold compounds [Au₂(dmpm)(dtc)]Cl (dmpm = Me₂PCH₂PMe_2,dtc = S₂CNEt₂), 1 , [Au₂(dppm)(dtc)]PF₆, (dppm = Ph₂PCH₂PPh₂),₂,and [Au₂(dppe)(dtc)]-(PF₂) (dppe = Ph₂P(CH₂)₂PPh₂), 3, were determined. All three compounds are dimetallacycles having two gold atoms bridged by a dithiolate ligand and a diphosphine ligand, the geometry around each gold atom being almost linear. All the dimetal lacy die rings are slightly distorted from planarity with intramolecular Au-Au distances shorter than 3.0 Å. Compound 1 forms a polymeric chain through intermolecular Au-Au contacts (3.061 ? 3.135 Å). Compound 2 forms a tetramer through intermolecular Au-Au interactions (Au-Au distances ranging from 3.086 to 3.222 ). Compound 3 is monomeric. All of the compounds luminesce at 77 K in the solid state. Emissions originating from ³LMCT from dtc ligand to Au excited states are assigned. The emission maxima of 1 ? 3 are at 541,535 and 520 nm respectively and are blue shifted as the number of Au-Au interactions is decreased.     

A new reaction of [Cp((CO)2Fe(PPh2H)]PF6 with NaBH4 to give Cp(CO)(H)Fe(PPh2H) via Cp(CO)2FeH and PPh2H

[Cp((CO)₂Fe(PPh₂H)]PF₆ reacts with NaBH₄ to give the intermediates CpFe(CO)₂H and PPh₂H, which are then converted into Cp(CO)(H)Fe(PPh₂H). [Cp(CO)₂FeL]PF₆ (L = P(OMe)₃, P(OEt)₃ and P(OⁱPr)₃) reacts with NaBH₄ to give the product Cp(CO)(H)FeL directly without Cp(CO)₂FeH and L even being formed transiently. The proposed reaction mechanism is that H⁻ attacks th phosphorus atom to give a metallaphosphorane complex, followed by coupling between a Cp(CO)₂Fe fragment and H on the hypervalent phosphorus.     

New octahedral bis(diphenylphosphino)methanide derivatives and heterometallic species from mixed ligand isocyanide-dppm iron(II) complexes

The cationic [FeL(dppm)(CNPh)₃]ⁿ⁺ (1a: L = I, n = 1; 1b: L = CNPh, n = 2) are readily deprotonated by KOH to give [FeL(dppm-H)(CNPh)₃]ⁿ⁻¹ (2a and 2b). 2a reacts with [thtAuPPh₃]PF₆ to give mer-[FeI((PPh₂)₂C(H)(AuPPh₃))-(CNPh)₃]PF₆ (3). The new heterotrimetallic species [FeL((PPh₂)₂C(AuPPh₃)₂)-(CNPh)₃]ⁿ⁺ (4a and 4b) have been obtained from 1a and 1b by treatment with ClAuPPh₃ in the presence of KOH.     

The Dynamic Behaviour and NMR Solution structures of complexes of the type (Bisphosphine)(cycloocta-1,5-diene)iridium(I) and the X-ray crystal structure of (cycloocta-1,5-diene)((−)-norphos)iridium(I) hexafluorophosphate

A square-planar coordination geometry was found for the complex [Ir(cod){(?)-norphos}][PF₆] ( 1b [PF₆]; cod = cylcoocta-1,5-diene and (?)-norphos = [(2R,3R)-8-9-10-trinorborn-5-ene-2,3-diyl]bis(diphenylphosphine)) in the solid state by X-ray diffraction. Crystal data: monoclinic, space group P2₁, a = 10.751 (6), b = 18.669(14), c = 12.037(8) Å, β = 114.82(5)°, Z = 2. A total structural assignment including the configurational and conformational aspects of this and the related compounds [Ir(bishosphine)(cod)]X (bisphosphine = (?)-chiraphos = (2S,3S)-2,3-bis(diphenylphosphino)butane and (?)-norphos, X = Cl, CF₃SO₃, or PF₆) was carried out in solution by one- and two-dimensional NMR spectroscopy. The complexes containing the CF₃SO₃^? and PF₆^? anions are four-coordinate cations with square-planar geometry, whereas the chlorides are five-coordinate neutral compounds showing solvent-dependent dynamic behaviour. In toluene, two diastereoisomers of [IrCl(cod){(?)-norphos}] ( 2b ) exist and interconvert slowly at room temperature. This interchange is fast in CDCl₃ solution, and it is likely to involve Cl dissociation and the formation of the cation [Ir(cod){(?)-norphos}]⁺ as an intermediate.     

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.     

Kinetics and mechanism of reaction of trans-(diaqua)(N,N′-ethylene-bis-salicylidenimine) chromium(iii) with sulfur(iv): The labilizing effect of coordinated sulfite

The reaction of trans-[Cr(Salen)(OH₂)₂]⁺ with aqueous sulfite yields trans-[Cr(Salen)(OH₂)(OSO₂(SINGLEBOND)O)]⁻ (O-bonded isomer). The rate and activation parameter data for the formation of the sulfito complex are consistent with a mechanism involving rate-limiting addition of SO₂ to the Cr^III(SINGLEBOND)OH bond. The complex ions, trans-[(OH₂)Cr(Salen)(OSO₂(SINGLEBOND)O)]⁻, and trans-[(OH)Cr(Salen)(OSO₂(SINGLEBOND)O)]²⁻, undergo reversible anation by NCS⁻, N₃⁻, imidazole, and pyridine resulting in the formation of trans-[XCr(Salen)(OSO₂(SINGLEBOND)O)]^(N+1)−(n=1 for X=N₃⁻,NCS⁻, and 0 for X=imidazole and pyridine) predominantly via dissociative interchange mechanism. The labilizing action of the coordinated sulfite on the trans-Cr^III-X bond in trans-[XCr(Salen)(OSO₂)]⁽ⁿ⁺¹⁾⁻ follows the sequence: NCS⁻pyridine ca. N₃⁻ ca. imidazole. Data analysis indicated that the coordinated sulfite has little trans activating influence. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 373–384, 1998