Electron‐Rich Diferrous–Phosphane–Thiolates Relevant to Fe‐only Hydrogenase: Is Cyanide “Nature's Trimethylphosphane”?

The two‐step one‐pot oxidative decarbonylation of [Fe₂(S₂C₂H₄)(CO)₄(PMe₃)₂] ( 1 ) with [FeCp₂]PF₆, followed by addition of phosphane ligands, led to a series of diferrous dithiolato carbonyls 2 – 6 , containing three or four phosphane ligands. In situ measurements indicate efficient formation of 1 ²⁺ as the initial intermediate of the oxidation of 1 , even when a deficiency of the oxidant was employed. Subsequent addition of PR₃ gave rise to [Fe₂(S₂C₂H₄)(μ‐CO)(CO)₃(PMe₃)₃]²⁺ ( 2 ) and [Fe₂(S₂C₂H₄)(μ‐CO)(CO)₂(PMe₃)₂(PR₃)₂]²⁺ (R=Me 3 , OMe 4 ) as principal products. One terminal CO ligand in these complexes was readily substituted by MeCN, and [Fe₂(S₂C₂H₄)(μ‐CO)(CO)₂(PMe₃)₃(MeCN)]²⁺ ( 5 ) and [Fe₂(S₂C₂H₄)(μ‐CO)(CO)(PMe₃)₄(MeCN)]²⁺ ( 6 ) were fully characterized. Relevant to the H_red state of the active site of Fe‐only hydrogenases, the unsymmetrical derivatives 5 and 6 feature a semibridging CO ligand trans to a labile coordination site.     

Binding H2, N2, H-, and BH3 to transition-metal sulfur sites: synthesis and properties of [RuL(PR3)(N2Me2S2)] Complexes (L=eta2-H2, H-, BH3; R=Cy, iPr)

The reactions of [Ru(N₂)(PR₃)(‘N₂Me₂S₂’)] [‘N₂Me₂S₂’=1,2‐ethanediamine‐N,N′‐dimethyl‐N,N′‐bis(2‐benzenethiolate)(2?)] [ 1 a (R=iPr), 1 b (R=Cy)] and [μ‐N₂{Ru(N₂)(PiPr₃)(‘N₂Me₂S₂’)}₂] ( 1 c ) with H₂, NaBH₄, and NBu₄BH₄, intended to reduce the N₂ ligands, led to substitution of N₂ and formation of the new complexes [Ru(H₂)(PR₃)(‘N₂Me₂S₂’)] [ 2 a (R=iPr), 2 b (R=Cy)], [Ru(BH₃)(PR₃)(‘N₂Me₂S₂’)] [ 3 a (R=iPr), 3 b (R=Cy)], and [Ru(H)(PR₃)(‘N₂Me₂S₂’)]^? [ 4 a (R=iPr), 4 b (R=Cy)]. The BH₃ and hydride complexes 3 a , 3 b , 4 a , and 4 b were obtained subsequently by rational synthesis from 1 a or 1 b and BH₃?THF or LiBEt₃H. The primary step in all reactions probably is the dissociation of N₂ from the N₂ complexes to give coordinatively unsaturated [Ru(PR₃)(‘N₂Me₂S₂’)] fragments that add H₂, BH₄^?, BH₃, or H^?. All complexes were completely characterized by elemental analysis and common spectroscopic methods. The molecular structures of [Ru(H₂)(PR₃)(‘N₂Me₂S₂’)] [ 2 a (R=iPr), 2 b (R=Cy)], [Ru(BH₃)(PiPr₃)(‘N₂Me₂S₂’)] ( 3 a ), [Li(THF)₂][Ru(H)(PiPr₃)(‘N₂Me₂S₂’)] ([Li(THF)₂]‐ 4 a ), and NBu₄[Ru(H)(PCy₃)(‘N₂Me₂S₂’)] (NBu₄‐ 4 b ) were determined by X‐ray crystal structure analysis. Measurements of the NMR relaxation time T₁ corroborated the η² bonding mode of the H₂ ligands in 2 a (T₁=35 ms) and 2 b (T₁=21 ms). The H,D coupling constants of the analogous HD complexes HD‐ 2 a (¹J(H,D)=26.0 Hz) and HD‐ 2 b (¹J(H,D)=25.9 Hz) enabled calculation of the H? D distances, which agreed with the values found by X‐ray crystal structure analysis ( 2 a : 92 pm (X‐ray) versus 98 pm (calculated), 2 b : 99 versus 98 pm). The BH₃ entities in 3 a and 3 b bind to one thiolate donor of the [Ru(PR₃)(‘N₂Me₂S₂’)] fragment and through a B‐H‐Ru bond to the Ru center. The hydride complex anions 4 a and 4 b are extremely Brønsted basic and are instantanously protonated to give the η²‐H₂ complexes 2 a and 2 b .     

过渡金属铁配合物Fe(CO)_(5-x)(PR_3)_x的结构与性质的理论研究

采用密度泛函理论(DFT)对一系列低价铁化合物Fe(CO)_(5-x)(PR_3)_x(x=1~3,R=H,F,Me)的几何结构、电子结构、成键特点以及热力学性质进行了理论研究。结果表明引入膦配体后不会造成Fe(CO)x(PR_3)_(5-x)的几何结构畸变,为略扭曲的三角双锥形。自然键轨道(NBO)分析显示,膦配体与羰基铁基团间存在电荷转移,有效增强Fe-CO之间的共价作用。多数稳定结构Fe(CO)x(PR_3)_(5-x)的第一膦配体解离能要比第一羰基解离能低,预示Fe(CO)_(5-x)(PR_3)_x的反应活性比Fe(CO)5有明显提高。     

Novel heterobimetallic complexes with S2CPR3(κ-S,S′)(κ-S,C,S′) bridges. X-Ray structure of [MnMo(CO)6(μ-Br)-(μ-S2CPiPr3)]

Reaction of fac-[Mn(CO)₃(S₂CPR₃)(Br)] with [Mo(CO)₃(NCMe)₃] produces a member of a novel class of heterodinuclear complex [MnMo(CO)₆(μ-Br)(μ-S₂CPR₃)] (R = Cy, ⁱPr), which contains S₂CPR₃ bridging ligands, acting as an (κ-S,S′) chelate towards Mn, and as an (κ-S,C,S′) pseudoallyl group to Mo, without a direct MoMn bond. One carbonyl group in [MnMo(CO)₆(μ-Br)(μ-S₂CPR₃)] can be easily displaced at room temperature by neutral ligands such as PEt₃ and P(OMe)₃, affording pentacarbonyl complexes, [MnMo(CO)₅(L)(μ-Br)(μ-S₂CPR₃].     

On the Coordination Properties of New Bicyclophosphite-Carbohydrates

Summary. The coordination behavior of newly developed bicyclophosphite ligands toward Mo(0), Rh(I), and Pt(II) was studied.Reactions at different ratios of metal to ligand were done. It was found that the ligands act as monodentate ones and form with hexacarbonylmolybdenum(0) complexes with the general formula Mo(CO)₅L by replacing only one carbonyl ligand. Coordination experiments toward acetylacetonatodicarbonylrhodium(I) resulted in the formation of undefined compounds. Toward dichlorocyclooctadienylplatinum(II) the monomeric phosphorus ligands act as monodentate ligands forming complexes of the general structure cis-PtCl₂L₂. All the synthesized platinum-complexes possess cis-configuration (proven by ³¹P NMR). The corresponding coordination compounds were isolated and characterized by elemental analyses and ¹H, ¹³C, and ³¹P NMR.     

Formation of Platinum–Tin Bond by Tin(II)Chloride Insertion

The first ¹¹⁹Sn NMR evidence for the presence of direct platinum–tin bond in solution has been obtained for PtCl(SnCl₃)(bdpp) complex (bdpp = (2S,4S)-2,4-bis(diphenylphosphino)pentane). Various PtCl₂(L₂) complexes (L₂ = heterobidentate P–P, P–O, P–N, P–S chelating ligands) have been reacted with tin(II)chloride resulting in the formation of the corresponding PtCl(SnCl₃)(L₂) derivatives. Tin(II)chloride has been inserted into the Pt–Cl bond transto the harder donor atom of the L₂ ligand.     

过渡金属铁配合物Fe(CO)5-x(PR3)x的结构与性质的理论研究

采用密度泛函理论（DFT）对一系列低价铁化合物Fe（CO）_5-x（PR₃）_x（x=1~3,R=H,F,Me）的几何结构、电子结构、成键特点以及热力学性质进行了理论研究。结果表明引入膦配体后不会造成Fe（CO）_x（PR₃）_5-x的几何结构畸变,为略扭曲的三角双锥形。自然键轨道（NBO）分析显示,膦配体与羰基铁基团间存在电荷转移,有效增强Fe-CO之间的共价作用。多数稳定结构Fe（CO）_x（PR₃）_5-x的第一膦配体解离能要比第一羰基解离能低,预示Fe（CO）_5-x（PR₃）_x的反应活性比Fe（CO）₅有明显提高。     

Synthesis,characterization, volatilization,alcoholysis and hydrolytic studies of nonaalkoxodititanatocopper(II) complexes

Heterobimetallic alkoxides of Cu(II) of the types [Cu{η⁴-Ti₂(OEt)₉}Cl] (1) and [Cu{η³-Ti₂(OR)₉}₂] [R = Prⁱ (2), R = Et(3)] have been prepared for the first time by the reactions of CuCl₂ · xROH with KTi₂(OR)₉ in 1:1 and 1:2 molar ratios, respectively, in benzene medium. The chloro(nonaalkoxo dititanato)copper(II) complexes undergo chloride replacement reactions by a variety of monodentate alkoxo (⁻OPrⁱ, ⁻OEt) and chelating [Al(OPrⁱ) ₄ ⁻ , Al(OEt) ₄ ⁻ , Nb(OPrⁱ) ₆ ⁻ , Zr₂(OPrⁱ) ₉ ⁻ , Sn₂(OPrⁱ) ₉ ⁻ , and Sn₂(OEt) ₉ ⁻ ] ligands to form interesting hetero(bi-and tri-)metallic complexes. Alcoholysis (with methyl alcohol and tert-butyl alcohol) and hydrolytic [with Ba(OH)₂ · 8H₂O powder] reactions of a few typical compounds have also been investigated. All of these have been characterized by elemental analyses, molecular weight determinations, spectral (i.r. and visible) and magnetic studies. On attempted volatilization under reduced pressure these complexes liberated titanium alkoxides as a volatile component leaving nonvolatile residues.     

Hydroformylation of oct-1-ene catalyzed by dinuclear gem-dithiolato-bridged rhodium(I) complexes and phosphorus donor ligands

The dinuclear gem-dithiolato bridged compounds [Rh₂(μ-S₂Cptn)(cod)₂] (1) (CptnS₂²⁻ = 1,1-cyclopentanedithiolato), [Rh₂(μ-S₂Chxn)(cod)₂] (2) (ChxnS₂²⁻ = 1,1-cyclohexanedithiolato), [Rh₂(μ-S₂CBn₂)(cod)₂] (3) (Bn₂CS₂²⁻ = 1,3-diphenyl-2,2-dithiolatopropane) and [Rh₂(μ-S₂CⁱPr₂)(cod)₂] (4) (ⁱPr₂CS₂²⁻ = 2,4-dimethyl-2,2-dithiolatopentane) dissolved in toluene in the presence of monodentate phosphine or phosphite P-donor ligands under carbon monoxide/hydrogen (1:1) atmosphere are efficient catalysts for the hydroformylation of oct-1-ene under mild conditions (6.8 atm of CO/H₂ and 80 °C). The influence of the gem-dithiolato ligand, the P-donor co-catalyst and the P/Rh ratio on the catalytic activity and selectivity has been explored. Aldehyde selectivities higher than 95% and turnover frequencies up to 245 h⁻¹ have been obtained using P(OMe)₃ as modifying ligand. Similar activity figures have been obtained using P(OPh)₃ although the selectivities are lower. Regioselectivities toward linear aldehyde are in the range 75–85%. The performance of the catalytic systems [Rh₂(μ-S₂CR₂)(CO)₂(PPh₃)₂]/PPh₃ has been found to be comparable to the systems [Rh₂(μ-S₂CR₂)(cod)₂] at the same P/Rh ratio. The system [Rh₂(μ-S₂CBn₂)(cod)₂] (3)/P(OPh)₃ has been tested in the hydroformylation-isomerization of trans-oct-2-ene. Under optimized conditions up to 54% nonanal was obtained. Spectroscopic studies under pressure (HPNMR and HPIR) evidenced the formation of hydrido mononuclear species under catalytic conditions that are most probably responsible for the observed catalytic activity.     

Synthesis and X-ray Molecular Structure Analysis of Some Au-Co,Au-Mn,and Hg-Co Bonded Compounds

The reaction of NaCo(CO)_4-x (PR₃) _x (x = 0, 1) with Au(PR₃)Cl was examined in THF. The products were characterized by single crystal X-ray analysis and/or XPS spectroscopy. When the THF solution of NaCo(CO)_4-x (PR₃) _x which was in situ prepared by the reduction of the corresponding cobalt carbonyl dimer with Na amalgam was filtered, the main product was (R₃P)Au-Co(CO)₄ and (R₃P)Au-Co(CO)_4-x (PR₃) _x (x = 1,2); phosphine migration from the Au to the Co site was observed for bulky phosphines during the recrystallization process. When the THF solution of NaCo(CO)_4-x (PR₃) _x was not filtered, the main product had the composition of M[Co(CO)₃(PR₃)]₂. The element M was clearly determined to be Hg by XPS spectroscopy. The reaction of NaMn(CO)₅ with Au(PR₃)Cl, however, afforded R₃PAu-Mn(CO)₅. The bonding parameters such as Au-M and Hg-Co bond-lengths were interpreted in terms of the electronic nature of the R group of the monodentate PR₃ ligand.     

Synthesis and characterization of monomeric palladium(II) pyridine-2-chalcogenolate complexes

Mononuclear palladium(II) complexes of the type [Pd(Epy)(S^∩S)(PPh₃)] [E=S or Se; S^∩S=S₂CNEt₂, S₂P(OR)₂ (R=Et, Prⁿ, Prⁱ)] have been prepared. All the complexes have been characterized by elemental analysis and NMR (¹H, ³¹P{¹H}, ⁷⁷Se{¹H}) spectral data. The NMR data indicate that there are two species in solution, i.e. one with chelating S^∩S ligand predominates (∼95%) while the other with chelating Epy and monodentate S^∩S existing in ∼5% concentration. The X-ray crystal structure of [Pd(Spy){S₂P(OPrⁱ)₂}(PPh₃)] has been determined. The square planar palladium atom is coordinated to asymmetrically chelated (PrⁱO)₂PS₂⁻ ligand, PPh₃ and pyS⁻ groups.     

Regioselektive Ringöffnungen von einfach ungesättigten triangularen Clusterkomplexen [M2Rh(μ‐PR2)(μ‐CO)2(CO)8] (M2 = Re2, Mn2; R = Cy,Ph; M2 = MnRe,R = Ph) mit Diphosphanen

Regioselective Ring Opening Reactions of Unifold Unsaturated Triangular Cluster Complexes [M₂Rh(μ‐PR₂)(μ‐CO)₂(CO)₈] (M₂ = Re₂, Mn₂; R = Cy, Ph; M₂ = MnRe, R = Ph) with Diphosphanes Equimolar amounts of the triangular title compounds and chelates of the type (Ph₂P)₂Z (Z = CH₂, DPPM ; C=CH₂, EPP ) react in thf solution at –40 to –20 °C under release of the labile terminal carbonyl ligand attached to the rhodium atom in good yields (70–90%) to ring‐opened unifold unsaturated complexes [MRh(μ‐PR₂)(CO)₄M(DPPM bzw. EPP)(μ‐CO)₂(CO)₃] (DPPM: M₂ = Re₂, R = Cy 1 , Ph 2 ; Mn₂, Cy 5 , Ph 6 ; MnRe, Cy 7 . EPP: M₂ = Re₂, R = Cy 8 ; Mn₂, Cy 10 ). Complexes 1 , 2 and 8 react subsequently under minor uptake of carbon monoxide and formation of the valence saturated complexes [ReRh(μ‐PR₂)(CO)₄M(DPPM bzw. EPP) (CO)₆] (DPPM: R = Cy 3 , Ph 4 . EPP: R = Cy 9 ). Separate experiments ascertained that the regioselective ring opening at the M–M‐edge of the title compounds is limited to reactions with diphosphanes chelates with only one chain member and that the preparation of the unsaturated complexes demands relatively good donor ability of both P atoms. As examples for both types of compounds the molecular structures of 8 and 3 have been determined from single crystal X‐ray structure analysis. Additionally all new compounds are identified by means of ν(CO)IR, ¹H‐ and ³¹P‐NMR data. This includes complexes with a modified chain member in 1 and 5 which, after deprotonation reaction to carbanionic intermediates, could be trapped with [PPh₃Au]⁺ cations as rac‐[MRh(μ‐PR₂)(CO)₄M((Ph₂P)₂CHAuPPh₃)(μ‐CO)₂(CO)₃] (M₂ = Re 17 , Mn 18 ) and products rac‐[MRh(μ‐PR₂)(CO)₄M((Ph₂P)₂CHCH₂R)(μ‐CO)₂(CO)₃] (M₂ = Re, R = Ph 19 , n‐Bu 21 , Me 23 ; Mn, Ph 20 , n‐Bu 22 , Me 24 ) which result from Michael‐type addition reactions of 8 or 10 with strong nucleophiles LiR.     

桥头碳上氮杂芳基功能化的双吡唑甲烷与羰基钨反应

研究了(氮甲基咪唑-2-基)双(3,5-二甲基吡唑)甲烷(L¹),2-吡啶基双(3,5-二甲基吡唑)甲烷(L²)及4-吡啶基双(3,5-二甲基吡唑)甲烷(L³)与羰基钨的反应,合成了一系列以单齿,双齿及三齿氮配位的羰基金属衍生物LW(CO)₅ (L=L¹或L³),LW(CO)₄ (L=L¹,L²或L³)和LW(CO)₃ (L=L¹或L²).核磁,红外及X-射线单晶衍射分析表明这3种配体表现出了可变的配位方式.在LW(CO)₅中,当配体为L¹时,其倾向于通过咪唑氮与金属配位,而为L³则倾向于利用吡啶氮与金属作用;在LW(CO)₄中,配体L¹表现为通过咪唑氮和吡唑氮原子配位的[N,N']双齿配体,而L²和L³表现为通过吡唑氮原子配位的[N,N]双齿配体;在LW(CO)₃中,L¹和L²起着[N,N,N']三齿螯合配体的作用.     

桥头碳上氮杂芳基功能化的双吡唑甲烷与羰基钨反应

研究了(氮甲基咪唑-2-基)双(3,5-二甲基吡唑)甲烷(L1),2-吡啶基双(3,5-二甲基吡唑)甲烷(L2)及4-吡啶基双(3,5-二甲基吡唑)甲烷(L3)与羰基钨的反应,合成了一系列以单齿,双齿及三齿氮配位的羰基金属衍生物LW(CO)5(L=L1或L3),LW(CO)4(L=L1,L2或L3)和LW(CO)3(L=L1或L2)。核磁,红外及X-射线单晶衍射分析表明这3种配体表现出了可变的配位方式。在LW(CO)5中,当配体为L1时,其倾向于通过咪唑氮与金属配位,而为L3则倾向于利用吡啶氮与金属作用;在LW(CO)4中,配体L1表现为通过咪唑氮和吡唑氮原子配位的[N,N′]双齿配体,而L2和L3表现为通过吡唑氮原子配位的[N,N]双齿配体;在LW(CO)3中,L1和L2起着[N,N,N′]三齿螯合配体的作用。     

Aqua­bis(3‐meth­oxy‐2‐pyridonato)­(2,2′:6′,2′′‐terpyridine)ruthenium(II)–acetonitrile–water (1/1/1)

The title compound, [Ru(C₆H₆NO₂)₂(C₁₅H₁₁N₃)(H₂O)]·CH₃CN·H₂O, is a transfer hydrogenation catalyst supported by nitro­gen‐donor ligands. This octa­hedral Ru^II complex features rare monodentate coordination of 3‐meth­oxy‐2‐pyridonate ligands and inter­ligand S(6)S(6) hydrogen bonding. Comparison of the title complex with a structural analog with unsubstituted 2‐pyridonate ligands reveals subtle differences in the orientation of the ligand planes.     

Preparation of chiral diimino- and diaminodiphosphine ligands and their Cu and Ag complexes. X-ray crystal structures of [Cu(1S,2S-cyclohexyl-P2N2)][PF6] and [Ag(1R,2R-cyclohexyl-P2N2H4)][BF4]

The interaction of optically pure 1R,2R-diammoniumyclohexane mono-(+)-tartrate and 1S,2S-diammoniumcyclohexane mono-(−)-tartrate with 2 equiv. of o-(diphenylphosphino)benzaldehyde in the presence of 2 equiv. of potassium carbonate in a refluxing ethanol/water mixture gave the optically pure condensation products N,N′-bis[o-(diphenylphosphino)benzylidene]-1R,2R-diiminocyclohexane[1R,2R-cyclohexyl-P₂N₂, (R,R)-I] and N,N′-bis[o-(diphenylphosphino)benzylidene]-1S,2S-diiminocyclohexane [1S,2S-cyclohexyl-P₂N₂, (S,S)-I], respectively, in good yield. Reduction of optically pure (R,R)-I and (S,S)-I with NaBH₄ in ethanol gave the optically pure reduced products N,N′-bis[o-(diphenylphosphino)benzylidene]-1R,2R-diaminocyclohexane[1R,2R-cyclohexyl-P₂N₂H₄, (R,R)-II] and N,N′-bis[o-diphenylphosphine)benzylidene]-1S,2S-diaminocyclohexane[1S,2S-cyclohexyl-P₂N₂H₄, (S,S)-II], respectively, in good yield. The coordination behaviour of I and II toward salts of Cu^I and Ag^I have been examined. The interaction of [Cu(C)₃CN)₄][X] (X = ClO₄⁻, PF₆⁻) with 1 equiv. of optically pure L₄ [L₄ = (R,R)-I, (S,S)-I, (R,R)-II and (S,S)-II] gave the corresponding optically pure [CuL₄][X] complexes, III–VI IIIa, L₄ = (R,R)-I, X = PF₆⁻ IIIb, L₄ = (R,R)-I, X = ClO₄⁻ IV, X = PF₆⁻; Va, L₄ = (R,R)-II, X = PF₆⁻, Vb L₄ = (R,R)-II, X= ClO₄⁻, VI L₄ = (S,S)-II, X = PF₆⁻, in good yield. For the Cu^I complexes, the L₄ ligand acted as a tetradentate ligand. However, a variable-temperature ³¹P[¹H] NMR study of IIIb shows that at ambient temperature one of the imino groups of the tetradentate ligand undergoes rapid dissociation to form a tridentate ligand. The interaction of AgBF₄ with 1 equiv. of otpically pure L₄ [L₄ = (R,R)-I, (S,S)-I, (R,R)-II and (S,S)-II gave the corresponding optically pure [AgL₄][BF₄] complexes, VII–X VII L₄ = (R,R)-I; VIII, L₄ = (S,S)-I; IX,L₄ = (R,R)-II; X, L₄ = (S,S)-II], in good yield. For the Ag^I complexes, the L₄ ligand acted as a tetradentate ligand with the two amino groups coordinated unsymmetrically to the silver. A variable temperature ³¹P [¹H] NMR study of VII suggests that at high temperature the complex exists as a tri-coordinated complex. The structurers of IV and IX were established by X-ray diffraction studies.     

Anionic and neutral rhodium(I) complexes containing trichlorostannato ligands

The complexes Et₄N[Rh(SnCl₃)₂(diolefin)(PR₃)] (diolefin = COD or NBD) have been isolated and their reactions studied. Reaction with arylic tertiary phosphines led to SnCl₃⁻ displacement and isolation of neutral pentacoordinated Rh(SnCl₃)(diolefin)(PR₃)₂ complexes. Reaction with carbon monoxide involved diolefin displacement when the diolefin was COD, thus giving Et₄N[Rh(SnCl₃)₂(CO)₂(PR₃)] compounds, but SnCl₃⁻ displacement when it was NBD, thus yielding Rh(SnCl₃)(CO)(NBD)(PR₃) complexes. The complexes [Rh(diolefin)Cl]₂ were found to react with triarylphosphines in the presence of SnCl₂ and with CO bubbling through the solution to give Rh(SnCl₃)(CO)(NBD)(PR₃) when the diolefin was NBD but Rh(Cl)(CO)(PR₃)₂ when the diolefin was COD.     

Elektronische effekte in cyclopentadienyl-chrom-komplexen,die mehrere akzeptorliganden enthalten

The coordinative properties of the acceptor ligand CS are discussed on the basis of the new thiocarbonyl complexes CpCr(CO)(CS)(NO) (I), [CpCr(CS)(NO)₂]PF₆ (II), CpCr(CS)(L)(NO) (L = pyridine (III) or trimethylphosphane (IV) and related carbonyl complexes. The IR and NMR spectra (¹H, ¹³C, ³¹P) of the complexes indicate ligand—ligand interactions between CS and both the nitrosyl group and the cyclopentadienyl ring. An attempt is made to compare CS with other sulphur-containing acceptor ligands such as NS (in CpCr(CO)₂(NS)) and CS₂ (in CpCr(CS₂)(PMe₃)(NO)).     

Synthesis,crystal structure and electrochemical properties of carbonylchromium and tungsten complexes containing substituted pyrazole ligands

A series of carbonylchromium and tungsten complexes containing substituted pyrazole ligands, M(CO)₅L, have been synthesized by the photochemical reactions of substituted pyrazoles with M(CO)₆ (M = Cr or W). Their electrochemical behavior, investigated by cyclic voltammetry, indicates that the chromium complexes exhibit one reversible or quasi-reversible couple corresponding to a one-electron oxidation, whereas the tungsten complexes have one irreversible oxidation process. The crystal structure of W(CO)₅L [L = 3(5)-t-butylpyrazole] was determined by X-ray diffraction, indicating that 3(5)-t-butylpyrazole is a monodentate ligand, and that the central metal is six-coordinate with a quasi-octahedral coordination geometry. All new compounds were characterized by elemental analyses, i.r., ¹H-n.m.r. and by ¹³C-n.m.r. in the case of the tungsten complexes.     

Synthesis and Crystal Structures of the Molybdenum(II) Complexes with the N,N‐dimethylthiocarbamoyl Containing Ligand: Crystal Structures of β [Mo(CO)2{η2‐S2P(OEt)2}(η2‐SCNMe2)(PPh3)] and [Mo(CO)2(η3‐Tp)(η2‐SCNMe2)(PPh3)]

Reactions of the thiocarbamoyl‐molybdenum complex [Mo(CO)₂(η²‐SCNMe₂)(PPh₃)₂Cl] 1 , and ammonium diethyldithiophosphate, NH₄S₂P(OEt)₂, and potassium tris(pyrazoyl‐1‐yl)borate, KTp, in dichloromethane at room temperature yielded the seven coordinated diethyldithiophosphate thiocarbamoyl‐molybdenum complexe [Mo(CO)₂{η²‐S₂P(OEt)₂}(η²‐SCNMe₂)(PPh₃)] β‐3 , and tris(pyrazoyl‐1‐yl)borate thiocabamoyl‐molybdenum complex [Mo(CO)₂(η³‐Tp)(η²‐SCNMe₂)(PPh₃)] 4 , respectively. The geometry around the metal atom of compounds β‐3 and 4 are capped octahedrons. The α‐ and β‐isomers are defined to the dithio‐ligand and one of the carbonyl ligands in the trans position in former and two carbonyl ligands in the trans position in later. The thiocabamoyl and diethyldithiophosphate or tris(pyrazoyl‐1‐yl)borate ligands coordinate to the molybdenum metal center through the carbon and sulfur and two sulfur atoms, or three nitrogen atoms, respectively. Complexes β‐3 and 4 are characterized by X‐ray diffraction analyses.