A structural investigation of the carbocation complex [{Cp(CO)2Fe}2{μ-(C3H5)}]PF6

The reaction of the propanediyl complex [{Cp^∗(CO)₂Fe}₂{μ-(C₃H₆)}] (Cp^∗ = η⁵-C₅(CH₃)₅) with the hydride abstractor Ph₃CPF₆ in dry CH₂Cl₂ resulted in the formation of the carbocation complex [{Cp^∗(CO)₂Fe}₂{μ-(C₃H₅)}]PF₆. The complex formed triclinic crystals in the space group with Z = 1. In the structure one metal is bonded in the η²-fashion, forming a chiral metallacyclopropane structure with the carbocation, while the other is σ-bonded to the same carbocation ligand. However, NMR evidence indicates that the structure observed in the solid state is not preserved in solution because the metallacyclopropane ring opens up, giving a structure in which more positive charge is localized on the β-CH carbon and which could be fluxional.     

Soft activation of the C-S bond: X-ray diffraction and spectroscopic study of the cluster Ru4(μ4-S)(μ,η3-C3H5)2(CO)12

The complex Ru₄(μ₄-S)(μ,η³-C₃H₅)₂(CO)₁₂ is prepared and examined by IR and NMR spectroscopy; its crystal structure is determined (an automatic Bruker-Nonius X8 Apex four-circle diffractometer equipped with a 2-D CCD-detector, 100 K, graphite-monochromated molybdenum source, λ = 0.71073 ?). The crystal belongs to the orthorhombic crystal system with unit cell parameters a = 19.3781(9) ?, b = 12.2898(7) ?, c = 10.1726(4) ?, V = 2422.6(2) ?³, space group Pnma, Z = 4, composition C₁₈H₁₀O₁₂Ru₄S, d _x = 2.343 g/cm³. The molecule of point symmetry C ₁ is situated on the mirror plane of the space group Pnma, two carbonyl groups at Ru2 and Ru3 atoms overlapping with the allylic ligand with a weight of 50% so that carbon atoms coincide. Thus, we have a racemic structure with two overlapping enantiomers of the molecule of Ru₄(μ₄-S)(μ,η³-C₃H₅)₂(CO)₁₂. Original Russian Text Copyright ? 2008 by I. Yu. Prikhod’ko, V. P. Kirin, V. A. Maksakov, A. V. Virovets, and A. V. Golovin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 4, pp. 748–752, May–June, 2008.     

A comparative study of the reactivity of unsaturated triosmium clusters [Os3(CO)8{μ3-Ph2PCH2P(Ph)C6H4}(μ-H)] and [Os3(CO)9{μ3-η-C7H3(2-Me)NS}(μ-H)] with BuNC

Treatment of unsaturated [Os₃(CO)₈{μ₃-Ph₂PCH₂P(Ph)C₆H₄}(μ-H)] (2) with ^tBuNC at room temperature gives [Os₃(CO)₈(CNBu^t)){μ₃-Ph₂PCH₂P(Ph)C₆H₄}(μ-H)] (3) which on thermolysis in refluxing toluene furnishes [Os₃(CO)₇(CNBu^t){μ₃-Ph₂PCHP(Ph)C₆H₄}(μ-H)₂] (4). Reaction of the labile complex [Os₃(CO)₉(μ-dppm)(NCMe)] (5) with ^tBuNC at room temperature affords the substitution product [Os₃(CO)₉(μ-dppm)(CNBu^t)] (6). Thermolysis of 6 in refluxing toluene gives 4. On the other hand, the reaction of unsaturated [Os₃(CO)₉{μ₃-η²-C₇H₃(2-Me)NS}(μ-H)] (7) with ^tBuNC yields the addition product [Os₃(CO)₉(CNBu^t){μ-η²-C₇H₃(2-Me)NS}(μ-H)] (8) which on decarbonylation in refluxing toluene gives unsaturated [Os₃(CO)₈(CNBu^t){μ₃-η²-C₇H₃(2-Me)NS}(μ-H)] (9). Compound 9 reacts with PPh₃ at room temperature to give the adduct [Os₃(CO)₈(PPh₃)(CNBu^t){μ-η²-C₇H₃(2-Me)NS(μ-H)] (10). Compound 8 exists as two isomers in solution whereas 10 occurs in four isomeric forms. The molecular structures of 3, 6, 8, and 10 have been determined by X-ray diffraction studies.     

Formation of the silylene-bridged complex Fe2(CO)6(μ2-SiCl2)3 from cis-Fe(CO)4(SiCl3)2: an experimental and computational study

Abstract  

Thermolysis of cis-Fe(CO)₄(SiCl₃)₂ results in the formation of the novel compound Fe₂(CO)₆(μ₂-SiCl₂)₃, which was characterized by single crystal X-ray diffraction. Density functional theory calculations were carried out to elucidate possible reaction steps leading to the formation of Fe₂(CO)₆(SiCl₂)₃, including CO dissociation and chlorine abstraction by a SiCl₃ radical generated from homolytic Fe–Si bond cleavage involving a singlet–triplet intersystem crossing.     

Discovering the chemical reactivity of the molecular oxonitride [{Ti(η-C5Me5)(μ-O)}3(μ3-N)]

The ability of the oxonitride [{Ti(η⁵-C₅Me₅)(μ-O)}₃(μ₃-N)] (1) to act as an organometallic ligand has been studied from both theoretical and experimental points of view. DFT calculations have allowed understanding the electronic structure of 1, and rationalizing its chemical behavior by comparison with the electronic structures of isoelectronic species [{Ti(η⁵-C₅Me₅)(μ-O)}₃(μ₃-CH)] and [{Ti(η⁵-C₅Me₅)(μ-NH)}₃(μ₃-N)]. Reactions of 1 with different inorganic molecules such as [Mo(CO)₃(1,3,5-Me₃C₆H₃)] or AlEt₃ have confirmed the possibility of 1 to act as a tridentate or monodentate ligand to give the [{(CO)₃Mo}(μ₃-O)₃{Ti₃(η⁵-C₅Me₅)₃(μ₃-N)}] (2) and [{Et₃Al}(μ₃-O){(μ-O)₂Ti₃(η⁵-C₅Me₅)₃(μ₃-N)}] (3) complexes, respectively. Surprisingly, reactions of 1 with [M(CO)₆] (M = Cr, Mo, W) complexes led to activate the μ₃-N unit in 1 to afford the new compounds [Ti₃(η⁵-C₅Me₅)₃(μ-O)₄{(NC)M(CO)₅}]₂ [M = Cr (4), Mo (5), W (6)]. Molecular structures of complexes 2-6 have been established by single crystal X-ray analysis.     

Reactivity of [Os3(CO)10(NCMe)2] and [Os3(CO)10(μ-Cl)(μ-AuPPh3)] with 4-mercaptopyridine: X-ray structure of [Os3(CO)10(μ-H)(μ-SC5H4N)] and [Os3(CO)10(μ-AuPPh3)(μ-SC5H4N)]

The compound [Os₃(CO)₁₀(μ-Cl)(μ-AuPPh₃)] (2) was prepared from the reaction between [Os₃(CO)₁₀(NCMe)₂] (1) and [AuClPPh₃] under mild conditions. The reaction of 2 with 4-mercaptopyridine (4-pyS) ligand yielded compounds [Os₃(CO)₁₀(μ-H)(μ-SC₅H₄N)] (4), formed by isolobal replacement of the fragment [AuPPh₃]⁺ by H⁺ and [Os₃(CO)₁₀(μ-AuPPh₃)(μ-SC₅H₄N)] (5). [Os₃(CO)₁₀(μ-H)(μ-SC₅H₄N)] (4) was also obtained by substitution of two acetonitrile ligands in the activated cluster 1 by 4-pyS, at room temperature in dichloromethane. Compounds 2-5 were characterized spectroscopically and the molecular structures of 4 and 5 in the solid state were obtained by single crystal X-ray diffraction studies.     

γ-Hydroxypropyl-functionalised iron thiolate complexes: crystal and molecular structure of [{Fe2(CO)6(μ-SCH2CH2CH2OH)}2(μ4-S)]

The γ-hydroxypropyl-functionalised diiron dithiolate complex [Fe₂(CO)₆(μ-SCH₂CH₂CH₂OH)₂] is prepared upon thermolysis of Fe₃(CO)₁₂ and HO(CH₂)₃SH and further reaction with dppm (dppm = Ph₂PCH₂PPh₂) affords [Fe₂(CO)₄(μ-dppm)(μ-SCH₂CH₂CH₂OH)₂]. From the reaction of Fe₃(CO)₁₂ with dppm(S₂) a minor product is the tetrairon cluster, [{Fe₂(CO)₆(μ-SCH₂CH₂CH₂OH)}₂(μ⁴-S)], the mode of formation of which is unclear. It has been crystallographically characterised and adopts a μ⁴-S bridged double butterfly structure which is compared with other crystallographically characterised complexes of this type. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Models of the iron-only hydrogenase: Reactions of [Fe2(CO)6(μ-pdt)] with small bite-angle diphosphines yielding bridge and chelate diphosphine complexes [Fe2(CO)4(diphosphine)(μ-pdt)]

Reactions of [Fe₂(CO)₆(μ-pdt)] (1) (pdt = SCH₂CH₂CH₂S) and small bite-angle diphosphines have been studied. A range of products can be formed being dependent upon the nature of the diphosphine and reaction conditions. With bis(diphenylphosphino)methane (dppm), thermolysis in toluene leads to the formation of a mixture of bridge and chelate isomers [Fe₂(CO)₄(μ-dppm)(μ-pdt)] (2) and [Fe₂(CO)₄(κ²-dppm)(μ-pdt)] (3), respectively. Both have been crystallographically characterised, 3 being a rare example of a chelating dppm ligand in a first row binuclear system. At room temperature in MeCN with added Me₃NO · 2H₂O, the monodentate complex [Fe₂(CO)₅(κ¹-dppm)(μ-pdt)] (4) is initially formed. Warming 4 to 100 °C leads the slow conversion to 2, while oxidation (on alumina) gives [Fe₂(CO)₅(κ¹-dppmO)(μ-pdt)] (5). With bis(dicyclohexylphosphino)methane (dcpm), heating in toluene cleanly affords [Fe₂(CO)₄(μ-dcpm)(μ-pdt)] (6). With Me₃NO · 2H₂O in MeCN the reaction is not clean as the phosphine is oxidised but monodentate [Fe₂(CO)₅(κ¹-dcpm)(μ-pdt)] (7) can be seen spectroscopically. With 1,2-bis(diphenylphosphino)benzene (dppb) and cis-1,2-bis(diphenylphosphino)ethene (dppv) the chelate complexes [Fe₂(CO)₄(κ²-dppb)(μ-pdt)] (8) and [Fe₂(CO)₄(κ²-dppv)(μ-pdt)] (9), respectively are the final products under all conditions, although a small amount of [Fe₂(CO)₅(κ²-dppvO)(μ-pdt)] (10) was also isolated. Protonation of 2 with HBF₄ affords a cation with poor stability while with the more basic diiron centre in 6 readily forms the stable bridging-hydride complex [(μ-H)Fe₂(CO)₄(μ-dcpm)(μ-pdt)][BF₄] (11) which has been crystallographically characterised.     

Unsaturation in binuclear cyclopentadienylchromium carbonyl thiocarbonyls: Viability of (η-C5H5)2Cr2(CS)2(CO)3 in contrast to (η-C5H5)2Cr2(CO)5

The cyclopentadienylchromium carbonyl thiocarbonyls Cp₂Cr₂(CS)₂(CO)_n (n = 4, 3, 2, 1) have been studied by density functional theory using the B3LYP and BP86 functionals. The lowest energy Cp₂Cr₂(CS)₂(CO)₄ structure can be derived from the experimentally characterized unbridged Cp₂Cr₂(CO)₆ structure by replacing the two terminal carbonyl groups furthest from the Cr-Cr bond with two terminal CS groups. The two lowest energy Cp₂Cr₂(CS)₂(CO)₃ structures have a single four-electron donor η²-μ-CS group and a formal Cr-Cr single bond of length ∼3.1 Å. In contrast to the carbonyl analogue Cp₂Cr₂(CO)₅ these Cp₂Cr₂(CS)₂(CO)₃ structures are viable with respect to disproportionation into Cp₂Cr₂(CS)₂(CO)₄ and Cp₂Cr₂(CS)₂(CO)₂ and thus are promising synthetic targets. The lowest energy Cp₂Cr₂(CS)₂(CO)₂ structures have all two-electron donor CO and CS groups and short CrCr distances around ∼2.3 Å suggesting the formal triple bonds required to give the chromium atoms the favored 18-electron configurations. These Cp₂Cr₂(CS)₂(CO)₂ structures are closely related to the known structure for Cp₂Cr₂(CO)₄. In addition, several doubly bridged structures with four-electron donor η²-μ-CS bridges are found for Cp₂Cr₂(CS)₂(CO)₂ at higher energies. The global minimum Cp₂Cr₂(CS)₂(CO) structure is a triply bridged triplet with a CrCr triple bond (2.299 Å by BP86). A higher energy singlet Cp₂Cr₂(CS)₂(CO) structure has a shorter Cr-Cr distance of 2.197 Å (BP86) suggesting the formal quadruple bond required to give each chromium atom the favored 18-electron configuration.     

Synthesis and X-ray investigation of novel Fe and Mn phenyltellurenyl-halide complexes: (CO)3FeBr2(PhTeBr), (η-C5H5)Fe(CO)2(PhTeI2) and CpMn(CO)2(PhTeI)

New complexes of transition metals with organotellurium halide ligands are reported. Iodination of [CpMn(CO)₂]₂(μ-Ph₂Te₂) leads to the Te-Te bond cleavage and formation of CpMn(CO)₂(PhTeI). Oxidative addition of PhTeBr₃ to Fe(CO)₅ gives the monomeric complex (CO)₃FeBr₂(PhTeBr) which is isostructural with the recently reported (CO)₃FeI₂(PhTeI). Insertion of phenyltellurenyl iodide (PhTeI) into the Fe-I bond of CpFe(CO)₂I forms CpFe(CO)₂(TeI₂Ph). Molecular structures of the reported complexes were determined by single-crystal X-ray diffraction analysis (XRD). A considerable shortening of metal-tellurium distances is observed.     

簇合物Co3(CO)7(μ3-S)[μ,η2-CNP(S)(C6H4OCH3)OC(Ph)CH]和Co3(CO)7(μ3-S)[μ,η2-SCNC(CH3)2P(S)(Cl)N(Ph)]的合成与晶体结构

用Co₂(CO)₈分别与两个杂环配体C(S)NHP(S)(C₆H₄OCH₃)OC(Ph)CH (L₁)和C(S)NHC(CH₃)₂P(S)(Cl)N(Ph) (L₂)反应,合成两个新的三核钴羰基硫簇合物Co₃(CO)₇(μ₃-S)[μ,η²-CNP(S)(C₆H₄OCH₃)OC(Ph)CH](Ⅰ)和Co₃(CO)₇(μ₃-S)[μ,η²-SCNC(CH₃)₂P(S)(Cl)N(Ph)](Ⅱ)。用元素分析,IR, ¹H NMR, ³¹P NMR及MS谱表征了它们的结构,同时用X射线衍射法测定了它们的晶体分子结构,二者属于三斜晶系,空间群P1,Ⅰ的晶胞参数为:a=0.84768(1)nm,b=1.19049(3)nm,c=1.43639(1)nm,α=86.926(1)°,β=81.601(3)°,γ=88.535(2)°,V=1.4318(5)nm³,Z=2,D_c=1.641g·cm^-3,F(000)=716,μ=1.893mm^-1,R=0.0602,R_w=0.1515。Ⅱ的晶胞参数为:a=1.2050(2)nm,b=1.2448(2)nm,c=0.8951(2)nm,α=97.49(1)°,β=93.552(4)°,γ=108.432(3)°,V=1.2554(3)nm³,Z=2,D_c=1.841g·cm^-3,F(000)=690,μ=2.419mm^-1,R=0.0423,R_w=0.1075。Ⅰ和Ⅱ的分子骨架Co3S为三角锥构型,S作为面桥基配体,所有CO作为端基配体与三个Co原子成键。Ⅰ中含有CoCoCN四元环组件,Ⅱ中含有CoCoSCN五元环组件。     

Two gold-ruthenium clusters derived from Ru3(μ-H)3(μ3-CBr)(CO)9

The reaction between AuMe(PPh₃) and Ru₃(μ-H)₃(μ₃-CBr)(CO)₉ (1) affords the novel heptanuclear cluster Au₄Ru₃(μ₃-CMe)(Br)(CO)₉(PPh₃)₃ (2), containing an Au/Ru₃/Au trigonal pyramidal cluster face-capped by two Au(PPh₃) groups and a CMe ligand, together with Au₂Ru₃(μ-H)(μ₃-CMe)(CO)₉(PPh₃)₂ (3), formed by isolobal replacement of two of the three μ-H atoms in 1 by Au(PPh₃) groups. The latter co-crystallises with the analogous μ₃-CH complex, as also shown spectroscopically.     

Crystal structure of [(C5Me4Et)3Rh3(μ3-Se)2](PF6)2CH3CN and [(C5Me4Et)2Rh2(μ2-Cl)3]PF6

The crystal structure of [(C₅Me₄Et)₃Rh₃(μ₃-Se)₂](PF₆)₂ and [(C₅Me₄Et)₂Rh₂(μ₂-Cl)₃]PF₆, obtained in the reaction of [(C₅Me₄Et)Rh(C₆H₆)](PF₆)₂ with ZnSe in 4M HCl under hydrothermal conditions, is determined. In agreement with the 18VE rule, the triangular cluster contains single metal-metal bonds (Rh-Rh 2.864(1) ?), whereas they are absent in the binuclear complex (Rh ...Rh 3,216(1) ?). Original Russian Text Copyright ? 2009 by P. A. Abramov, M. N. Sokolov, A. V. Virovets, and V. P. Fedin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 1, pp. 169–172, January–February, 2009.     

A comparison between the reaction of P2Ph4 with [{Co2(CO)6}2(μ-η:μ-η-HOCH2CCCCCH2OH)] and the reaction of [Co2(μ-PPh2)2(CO)6] with HOCH2CCCCCH2OH

Reaction of P₂Ph₄ with the diyne-diol complex [{Co₂(CO)₆}₂(μ-η²:μ-η²-HOCH₂CCCCCH₂OH)] in toluene at 65 °C gives [{Co₂(μ-P₂Ph₄)(CO)₄}{Co₂(CO)₆}(μ-η²:μ-η²-HOCH₂CCCCCH₂OH)] (1). Thermolysis of 1 at 95 °C leads to [{Co₂(CO)₅}₂(μ-P₂Ph₄)(μ-η²:μ-η²-HOCH₂CCCCCH₂OH)](2) and (μ₂-PPh₂)(μ₂-CO)(CO)₇] (3). The structures of 1-3 have been established by X-ray crystallography. In 1, a pseudoequatorial P₂Ph₄ ligand bridges the cobalt-cobalt bond of a Co₂(CC)(CO)₄ unit. By contrast, in isomeric 2, a pseudoaxial P₂Ph₄ ligand spans two Co₂(CC)(CO)₅ units, a new coordination mode for [{Co₂(CO)₅L}₂(μ-η²:μ-η²-diyne)] complexes. Complex 3 arises from dehydration-cyclocarbonylation of the diyne-diol in 1 to give a 2(5H)-furanone, a process that has not been previously reported. Reaction of HOCH₂CCCCCH₂OH with [Co₂(μ-PPh₂)₂(CO)₆] at 80 °C in toluene gave [Co₃(μ-PPh₂)₃(CO)₆], [Co₂(CO)₆(μ-η²-HOCH₂CCCCCH₂OH)] and [Co₂{μ-η⁴-PPh₂C(CCCH₂OH)C(CH₂OH)CO}(μ-PPh₂)(CO)₄] (4). The regiochemistry of 4 was confirmed by X-ray crystallography.     

Reactions of a phosphido-bridged unsymmetrical diiron complex (η-C5Me5)Fe2(CO)4(μ-CO)(μ-PPh2) with various alkynes

A phosphido-bridged unsymmetrical diiron complex (η⁵-C₅Me₅)Fe₂(CO)₄(μ-CO)(μ-PPh₂) (1) was synthesized by a new convenient method; photo-dissociation of a CO ligand from (η⁵-C₅Me₅)Fe₂(CO)₆(μ-PPh₂) (2) that was prepared by the reaction of Li[Fe(CO)₄PPh₂] with (η⁵-C₅Me₅)Fe(CO)₂I. The reactivity of 1 toward various alkynes was studied. The reaction of 1 with ^tBuCCH gave a 1:1 mixture of two isomeric complexes (η⁵-C₅Me₅)Fe₂(CO)₃(μ-PPh₂)[μ-CHC(^tBu)C(O)] (3) containing a ketoalkenyl ligand. The reactions of 1 with other terminal alkynes RCCH (R=H, CO₂Me, Ph) afforded complexes incorporating one or two molecules of alkynes and a carbonyl group. The principal products were dinuclear complexes bridged by a new phosphinoketoalkenyl ligand, (η⁵-C₅Me₅)Fe₂(CO)₃(μ-CO)[μ-CR¹CR²C(O)PPh₂] (4a: R¹=H, R²=H; 4b: R¹=CO₂Me, R²=H; 4c: R¹=H, R²=Ph). In the cases of alkynes RCCH (R=H, CO₂Me), dinuclear complexes having a new ligand composed of two molecules of alkynes, a carbonyl group, and a phosphido group; i.e. (η⁵-C₅Me₅)Fe₂(CO)₃[μ-CRCHCHCRC(O)PPh₂] (5a: R=H; 5b: R=CO₂Me), were also obtained. In all cases, mononuclear complexes, (η⁵-C₅Me₅)Fe(CO)[CR¹CR²C(O)PPh₂] (6a: R¹=H, R²=H; 6b: R¹=H, R²=CO₂Me; 6c: R¹=H, R²=Ph) were isolated in low yields. The structures of 1, 4c, 5b, and 6a were confirmed by X-ray crystallography. The detailed structures of the products and plausible reaction mechanisms are discussed.     

Unsymmetrical alkyne binding to a triruthenium centre: Oxidative-addition of diphenyl ditelluride to the furyne cluster [Ru3(CO)7(μ-H)(μ3-η-C4H2O){μ-P(C4H3O)2}(μ-dppm)]

Oxidative-addition of PhTe₂Ph to the furyne cluster [Ru₃(CO)₇(μ-H)(μ₃-η²-C₄H₂O){μ-P(C₄H₃O)₂}(μ-dppm)] (1) results in the isolation of four complexes; (i) the previously reported 54-electron cluster [Ru₃(CO)₆(μ₃-Te)₂(μ-TePh)₂(μ-dppm)] (5) which results from elimination of trifuryl phosphine, (ii) the furenyl cluster [Ru₃(CO)₅(μ-η²-C₄H₃O){μ-P(C₄H₃O)₂}(μ-TePh)₂(μ-dppm)] (6) which results from carbon-hydrogen bond formation and (iii) two new 50-electron complexes [Ru₃(CO)₅(μ-H)(μ₃-η²-C₄H₂O){μ-P(C₄H₃O)₂}(μ-TePh)₂(к²-dppm)] (7) and [Ru₃(CO)₄(μ-H){P(C₄H₃O)₃}(μ₃-η²-C₄H₂O){μ-P(C₄H₃O)₂}(μ-TePh)₂(к²-dppm)] (8) both containing unsymmetrical furyne ligands. The structures of all the new compounds have been unambiguously established by single crystal X-ray crystallography. Further reactivity studies have provided a clear understanding of the relative sequence of the key oxidative-addition and reductive-elimination processes, showing that 6 is an intermediate in the formation of 7. DFT calculations have been used to shed light on the unsymmetrical binding of the furyne ligand in 7 and also to show that the adopted position of the heteroatom within the furyne ring can vary within complexes of this type.     

Facile and highly efficient light-induced PR3/CO ligand exchange: A novel approach to the synthesis of [(μ-SCH2NPrCH2S)Fe2(CO)4(PR3)2]

A straightforward and efficient transformation of the Fe-S complex [(μ-SCH₂NⁿPrCH₂S)Fe₂(CO)₆] to its double phosphine coordinated analogues [(μ-SCH₂NⁿPrCH₂S)Fe₂(CO)₄(PR₃)₂] (R = Ph, Me) is described. The single crystal structure of the PPh₃-disubstituted complex [(μ-SCH₂NⁿPrCH₂S)Fe₂(CO)₄(Ph₃P)₂] (3) showed that both of the phosphine ligands take an apical/apical instead of a basal/basal or an apical/basal configuration.     

Dynamic behavior of [(η-C5H4CH3)Cr(CO)2(μ-SBu)Pt(PPh3)2] in solution

The structure and dynamic behavior of complex [(η⁵-C₅H₄CH₃)Cr(CO)₂(μ-SBu)Pt(PPh₃)₂] in solution was studied by multinuclear (¹H, ¹³C, ³¹P) NMR spectroscopy including a phase-sensitive NOESY experiment. Increasing temperature causes rupture of the Cr-Pt bond in the three-membered ring of the complex and rotation of the S-Pt(PPh₃)₂ unit around the Cr-S bond line, followed by formation of a new Cr-Pt bond to close the ring. All activation parameters for this dynamic process have been determined.     

Synthesis and reaction chemistry of [(μ-SeR)(μ-σ,π-CCPh)]Fe2(CO)6

RSeCCPh (1a, R = Et; 1b, R = n-Bu; 1c, R = Ph; 1d, R = 2,4,6-Me₃C₆H₂) reacts with equimolar amounts of Fe₂(CO)₉ (2) to give [(μ-SeR)(μ-σ,π-CCPh)]Fe₂(CO)₆ (3a, R = Et; 3b, R = n-Bu; 3c, R = Ph; 3d, R = 2,4,6-Me₃C₆H₂).Complexes 3a-3d exist as two isomers, depending on the axial or equatorial position of R at selenium.Addition of P(OⁱC₃H₇)₃ (4) to 3d affords {(μ-Se-2,4,6-Me₃C₆H₂)[μ-η¹-CCPh(P(OⁱC₃H₇)₃)]}Fe₂(CO)₆ (5) along with {(μ-Se-2,4,6-Me₃C₆H₂)[μ-η¹:η¹-PhCC(P(OⁱC₃H₇)₃)]}Fe₂(CO)₆ (6).The solid-state structures of 3d, 5 and 6 were determined by single X-ray structure analysis.In mononuclear 3d the Fe(CO)₃ fragments are bridged by a μ-Se-2,4,6-Me₃C₆H₂ and a μ-σ,π-CCPh unit, resulting in an over-all butterfly arrangement.Due to steric reasons, the mesityl group is pointing away from the PhCC entity and hence, is located in an equatorial position.Compounds 5 and 6, which co-crystallise in the ratio of 7:93, feature aμ-bridging 2,4,6-Me₃C₆H₂Se unit and either a vinylidenic CCPh(P(OⁱC₃H₇)₃) (complex 5) or a olefinic PhCC(P(OⁱC₃H₇)₃) (complex 6) building block of which the latter entity is part of a diiron cyclobutene ring.     

Oxidative addition of the Mo-Cl bond to the Pt0 complex. Synthesis and structure of Cp′Mo(μ-CO)2(C2Ph2)Pt2(PPh3)2(CO)Cl

A reaction of Cp′Mo(CO)₃Cl(Cp′ = MeC₅H₄) with (PPh₃)₂Pt(C₂Ph₂) gave the heterometallic cluster Cp′Mo(μ-CO)₂(C₂Ph₂)Pt₂(PPh₃)₂(CO)Cl (I) as the sole product. According to X-ray diffraction data, complex I contains single Pt-Mo bonds (2.7962(5) and 2.7699(5) ?) but no Pt-Pt bond (Pt…Pt 2.9746(3) ?). The coordinated diphenylacetylene molecule forms two Pt-C σ-bonds (2.054(6) and 2.083(5) ?) and a π-bond to the Mo atom (Mo-C 2.265(6) and 2.272(5) ?; C≡C 1.387(8) ?). Original Russian Text ? A.A. Pasynskii, I.V. Skabitskii, Yu.V. Torubaev, S.S. Shapovalo, 2009, published in Koordinatsionnaya Khimiya, 2009, Vol. 35, No. 6, pp. 410–413.