Phenyltellurolate-bridged heterometallic complexes combining rhenium tricarbonyl with (dicarbonyl)(cyclopentadienyl)iron or bis(diphenylphosphino)ethaneplatinum

A reaction of CpFe(CO)₂TePh with Re(CO)₃(THF)₂Cl in THF gave the heterometallic complex [CpFe(CO)₂(μ-TePh)]₂Re(CO)₃Cl (I). Either iron atom in complex I is linked to rhenium by only one Phenyltellurolate bridge. When treated with (Dppe)Pt(TePh)₂, complex I underwent transmetalation by elimination of two CpFe(CO)₂TePh molecules followed by the formation of the heterometallic chelate complex (Dppe)Pt(μ-TePh)₂Re(CO)₃Cl (II). Complex II was also obtained in an independent way from (Dppe)Pt(TePh)₂ and Re(CO)₃(THF)₂. Structures I and II (II · MePh and II · CDCl₃) were identified by X-ray diffraction (CIF file, CCDC nos. 981467, 981468, and 981469, respectively).     

Neutral and monocationic dinuclear (carbonyl)(cyclopentadienyl)(phenylchalcogenate) iron complexes of the general formulas [(RC5H4)Fe(CO)EPh]2 and [(RC5H4)Fe(CO)EPh]2PF6 (E = S or Te; R = H or Me): Synthesis, molecular structures, and EPR spectra

Heating of the compounds (RC₅H₄)Fe(CO)₂TePh (R = H (I) and Me (II)) in heptane afforded the dinuclear complexes [(RC₅H₄)Fe(CO)TePh]₂ (III and IV, respectively). By oxidation with Fc⁺PF ₆ ^? , these complexes were transformed into the paramagnetic cationic complexes [(RC₅H₄)Fe(CO)TePh]₂PF₆ (V and VI, respectively). Structures III–V and [(C₅H₅)Fe(CO)SPh]₂PF₆ (VII) were characterized by X-ray diffraction.     

Platinum and rhenium phosphine carbonyl thiolate complexes

The heterometallic complex (CO)₃(PPh₃)Re(μ-SPr)Pt(PPh₃)(CO) (I) was formed in the reaction of Re₂(μ-SPr)₂(CO)₈ with (PPh₃)₂Pt(C₂Ph₂), together with (CO)₃(PPh₃)Re(μ-SPr)₂Re(CO)₄ (II), which was also prepared by an alternative synthesis. Compounds I and II were characterized by X-ray diffraction. In I, the Re-Pt single bond, 2.7414(5) Å, is supplemented by a thiolate bridge with shortened bonds: Pt-S (2.336(2) Å) and Re-S (2.449(2) Å). The Re-P (2.469(2) Å) and Pt-P (2.329(2) Å) bonds are also shortened. Complex II resulting from replacement of one CO group in the starting rhenium complex by triphenylphosphine has no M-M bond, and the Re-S and Re-P bond lengths (2.511(2)–2.527(2) and 2.517(3) Å) are close to the length of single bonds. It is assumed that the platinum atom in I is attached to the formally double bond Re ? SPr arising upon dissociation of Re₂(μ-SPr)₂(CO)₈.     

Heterometallic derivatives of dicarbonylcyclopentadienylrhenium disulfide containing chromium pentacarbonyl and bis(triphenylphosphine)platinum

The reaction of Cp′Re(CO)₂THF (Cp′ = C₅H₄Me), THF is tetrahydrofuran) with sulfur affords Cp′Re(CO)₂S₂(I) and [Cp′Re(CO)₂]₂S (II). The synthesized compounds are isolated chromatographically and characterized by X-ray diffraction analysis. The adduct Cp′Re(CO)₂S₂Cr(CO)₅ (III) is synthesized by the reaction of compound I with Cr(CO)₅(THF). The adduct CpRe(CO)₂S₂Cr(CO)₅ (IV) is obtained similarly from known CpRe(CO)₂S₂ and Cr(CO)₅(THF). The reaction of compound I with (PPh₃)₂Pt(C₂Ph₂) results in the removal of Ph₂C₂ and one sulfur atom to form Cp′Re(CO)₂SPt(PPh₃)₂ (V). The structures of compounds I–V are determined by X-ray diffraction analysis (CIF files CCDC nos. 984554 (I), 984555 (II), 984556 (III), 984557 (IV), and 984558 (V)). Compound I contains the three-membered cycle ReS₂ with the ordinary S-S bond (2.044(4) Å) and shortened Re-S bonds (average 2.434(3) Å). The three-membered cycle Re₂S containing the ordinary Re-Re bond (2.932(1) Å) and shortened Re-S bonds (2.371(1) Å) is observed in compound II. In compounds III and IV, the formation of the ordinary S-Cr(CO)₅ bond (2.406(1) Å) with one of the sulfur atoms almost does not change the geometry of the ReS₂ fragment. The thermal decomposition of compound III proceeds with the elimination of six CO ligands in the range 110–160°C and then with the loss of CO and Cp′ in the range 160–430°C and the formation of the inorganic residue ReCrS₂. Compound V contains the triangular framework ReSPt with the ordinary Pt-Re bond (2.7882(3) Å) and substantially shortened bonds Re-S (2.3984(9) Å) and Pt-S (2.2724(8) Å). It is assumed that compounds II and V can be presented as products of the π-coordination of the double bonds in Cp′(CO)₂Re=S with the Cp′Re(CO)₂ or Pt(PPh₃)₂ groups, respectively.     

Osmium-carbonyl complexes of naphthylazoimidazoles. Single crystal X-ray structure of [Os(H)(CO)(PPh3)2(α-NaiEt)](PF6) {α-NaiEt = 1-ethyl-2-(naphthyl-α-azo)imidazole}

1-Alkyl-2-(naphthyl-α/β-azo)imidazole (α-NaiR 1; β-NaiR, 2) react with [Os(H)(Cl)(CO)(PPh₃)₃] in THF and synthesise [Os(H)(CO)(PPh₃)₂(α/β-NaiR)](PF₆) (3, 4). The X-ray structure of [Os(H)(CO)(PPh₃)₂(α-NaiEt)](PF₆) (3c) shows a distorted octahedral geometry. Other spectroscopic studies (IR, UV–Vis, NMR) support the stereochemistry of the complexes. Addition of Cl₂ in MeCN to 3 or 4 gives [Os(Cl)(CO)(α/β-NaiR)(PPh₃)₂](PF₆) (5, 6), which were characterized by spectroscopic studies. The redox properties of the complexes show Os(III)/Os(II), Os(IV)/Os(III) and azo reductions.     

Synthesis, molecular structures, and properties of heterometallic cobalt tetramethylcyclobutadiene complexes (C4Me4)Co(CO)2TePh, (C4Me4)Co(CO)2TePh[W(CO)5], and Me4C4Co(μ3-S)2Cr2Cp2(μ-SC4H9)

The reaction of Cb*Co(CO)₂I (1) (Cb* is tetramethylcyclobutadiene) with sodium phenyltelluride afforded the mononuclesar complex Cb*Co(CO)₂TePh (2). The reaction of the latter with W(CO)₅(THF) produced the Cb*Co(CO)₂TePh[W(CO)₅] compound (4). The reaction of 1 with the Cp₂Cr₂(SCMe₃)₂S complex gave the heterometallic cluster Cb*Co(μ₃-S)₂Cr₂Cp2 (μ-SCMe₃) (5). Complexes 2, 4, and 5 are diamagnetic. Their structures were determined by X-ray diffraction. Complex 2 contains the Co-Te bond (2.585(1) Å); complex 4, the Co-Te (2.558(8) Å) and W-Te (2.8467(6) Å) bonds. Complex 5 has the stable triangular sulfide-and tert-butylmercaptide-bridged core Cr₂Co (Cr-Cr and Cr-Co bond lengths are 2.626(2) and 2.673(2) Å, respectively) with Cp ligands at the chromium atoms and a Cb* ligand at the cobalt atom. Complex 5 was characterized by cyclic voltammetry. The thermolysis of complex 4 was studied.     

Trichlorostannyl and tris(phenylacetylenide)stannyl complexes of manganese cyclopentadienylcarbonylnitrosyl: Synthesis and molecular structures

The heating of the ionic complex [CpMn(CO)₂(NO)]⁺SnCl₃-(I) in methylene chloride gives a neutral complex CpMn(CO)(NO)SnCl₃ (II). The latter reacts with lithium phenylacetylenide to yield a complex CpMn(CO)(NO)Sn(C≡CPh)₃ (III). According to the X-ray diffraction data, complexes II and III contain shortened Mn-Sn bonds (2.5178(5) and 2.5436(12) Å, respectively).     

The complex of dicarbonyl(methylcyclopentadienyl)molybdenum with carbonyl(cyclopentadienyl)nitrosyl[tris(phenylacetylenide)stannyl]manganese: Synthesis and molecular formula

A reaction of CpMn(CO)(NO)Sn(C=CPh)₃ (I) with [Cp′Mo(CO)₂]₂ (Cp′ = MeC₅H₄) gave CpMn(CO)(NO)Sn(C=CPh)₃[Cp′Mo(CO)₂]₂ (II) as dark red prismatic crystals. The molecular structure of complex II was determined by X-ray diffraction study. Complex II contains the Mo-Mo bond (2.9799(5) Å), which is perpendicular to the coordinated C=C bond. The latter is longer (1.371(5) Å) than free acetylenide fragments (1.190(5) and 1.198(5) Å). In addition, the angle Sn-C=C for the coordinated C=C bond is smaller (134.1(3)°) than that in free fragments (173.5(4)° and 171.9(4)°). The Mn-Sn bond length in complex II (2.5662(7) Å) is close to that in complexI (2.5328(17) Å) and is much shorter than the sum of the corresponding covalent radii (2.78 Å). The Sn-C bond (2.108(4) Å) in the acetylenide fragment π-bound to two Mo atoms (average Mo-C, 2.19 Å), as well as the other Sn-C bonds (2.119(4) and 2.135(4) Å), remains virtually the same as in complex I (average 2.105 Å).     

Reactivity of the heteronuclear cluster Cp*IrOs3(μ-H)2(CO)10 with some group 16 substrates

The mixed metal cluster Cp*IrOs₃(μ-H)₂(CO)₁₀ (1) reacted readily with a number of group 16 substrates under chemical activation with TMNO. It reacted with C₆H₅SH to afford the novel cluster Cp*IrOs₃(μ-H)₃(CO)₉(μ-SPh) (2). It also reacted readily with Ph₃PSe to afford five new clusters, viz., Cp*IrOs₃(μ-H)₂(CO)₉(μ₃-Se) (3) Os₃(μ-H)₂(CO)₇(μ₃-Se)(PPh₃)₂ (4), Cp*IrOs₃(μ-H)₂(CO)₉(PPh₃) (5), Cp*IrOs₃(μ-H)₂(μ₃-Se)(CO)₈(PPh₃) (6) and Cp*IrOs₃(μ-H)₂(μ₃-Se)₂(CO)₇(PPh₃) (7). The reaction pathway for this reaction has been studied carefully and suggests that Ph₃PSe functioned primarily as a selenium atom transfer agent to give initially the even more reactive 3. The reaction of 1 with di-p-tolyl ditelluride yielded three new clusters, 8-10, which were non-interconverting stereoisomers with the formulation Cp*IrOs₃(μ-H)₂(μ-Te-p-C₆H₄CH₃)₂(CO)₈.     

Some ruthenium complexes containing cyanocarbon ligands: syntheses, structures and extent of electronic communication in binuclear systems

The preparation of several ruthenium complexes containing cyanocarbon anions is reported. Deprotonation (KOBu^t) of [Ru(NCCH₂CN)(PPh₃)₂Cp]PF₆ (1) gives Ru{NCCH(CN)}(PPh₃)₂Cp (2), which adds a second [Ru(PPh₃)₂Cp]⁺ unit to give [{Ru(PPh₃)₂Cp}₂(μ-NCCHCN)]⁺ (3). Attempted deprotonation of the latter to give the μ-NCCCN complex was unsuccessful. Similar chemistry with tricyanomethanide anion gives Ru{NCC(CN)₂}(PPh₃)₂Cp (4) and [{Ru(PPh₃)₂Cp}₂{μ-NCC(CN)CN}]PF₆ (5), and with pentacyanopropenide, Ru{NCC(CN)C(CN)C(CN)₂}(PPh₃)₂Cp (6) and [{Ru(PPh₃)₂Cp}₂{μ-NCC(CN)C(CN)C(CN)CN}]PF₆ (7). The Ru(dppe)Cp* analogues of 6 and 7 (8 and 9) were also prepared. Thermolysis of 6 (refluxing toluene, 12 h) results in loss of PPh₃ and formation of the binuclear cyclic complex {Ru(PPh₃)Cp[μ-NC{C(CN)C(CN)₂}CN]}₂ (10). The solid-state structures of 2-4 and 8-10 have been determined and the nature of the isomers shown to be present in solutions of the binuclear cations 7 and 9 by NMR studies has been probed using Hartree-Fock and density functional theory.     

Diphenyldichalcogenide complexes of iron, chromium and rhenium carbonyls

The substitution of a labile THF ligand in Cr(CO)₅(THF) by the Ph₂Se₂ molecule provided the monomeric complex Cr(CO)₅(Ph₂Se₂) (I). The similar diiodo-tricarbonyl-iron complex (CO)₃FeI₂(Ph₂Se₂) (II) (along with [(CO)₃Fe(??-SePh)₃Fe(CO)₃]⁺(I₅)^? (III) as a by-product) was separated upon the treatment of ??phenylselenyl iodide?? [PhSeI] with iron pentacarbonyl, Fe(CO)₅. Complex II is isostructural with the known tellurium-containing analogue, (CO)₃FeI₂(Te₂Ph₂). The latter have provided the dimeric tellurophenyl bridged iodo-tricarbonyl-iron complex [(CO)₃IFe(??-TePh)]₂ (IV) under action of the excess of Fe(CO)₅. Its bromide analogue [(CO)₃BrFe(??-TePh)]₂ (V) was prepared upon the treatment of PhTeBr with the excess of Fe(CO)₅. The reaction of [PhSeI] with Re(CO)₅Cl afforded only [(CO)₆Re₂(??-I)₂(??-Se₂Ph₂)] (VI) in contrast to the (CO)₃Re(PhTeI)₃(??₃-I) formation in similar known reaction of [PhTeI]. The molecular and crystal structures of I?CVI is discussed.     

Diastereoselectivity at chiral metal center of half-sandwich-type ruthenium complexes with planar-chiral cyclopentadienyl ligands in multiple ligand transfer reaction

The triple ligand transfer reaction between planar-chiral cyclopentadienyl-ruthenium complexes [Cp′Ru(NCMe)₃][PF₆] (1) (Cp′ = 1-(COOR²)-2-Me-4-R¹C₅H₂; R¹ = Me, Ph, t-Bu) and iron complexes CpFe(CO)(L)X (2) (L = PMe₃, PMe₂Ph, PMePh₂, PPh₃; X = I, Br) resulted in the formation of metal-centered chiral ruthenium complexes Cp′Ru(CO)(L)X (3) in moderate yields with diastereoselectivities of up to 68% de. The configurations of some major diastereomers were determined to be by X-ray crystallography. The diastereoselectivity of 3 was under kinetic control and not affected by the steric effect of the substituents on the Cp′ ring of 1 and the phosphine of 2. Although the double ligand transfer reaction between [Cp′Ru{P(OMe)₃}(NCMe)₂][PF₆] (7) and CpFe(CO)₂X (8) produced Cp′Ru{P(OMe)₃}(CO)X (9), the selectivity at the ruthenium center was low.     

Synthesis and structure of sulfur and selenium capped dihydride triruthenium clusters [Ru3(CO)7(μ-H)2(μ-dppm)(μ3-E)] (E = S, Se)

Reaction of [Ru₃(CO)₁₀(μ-dppm)] (1) with H₂S at 66 °C affords high yields of the sulfur-capped dihydride [Ru₃(CO)₇(μ-H)₂(μ-dppm)(μ₃-S)] (2), formed by oxidative-addition of both hydrogen-sulfur bonds. Hydrogenation of [Ru₃(CO)₇(μ-dppm)(μ₃-CO)(μ₃-S)] (3) at 110 °C also gives 2 in similar yields, while hydrogenation of [Ru₃(CO)₇(μ-dppm)(μ₃-CO)(μ₃-Se)] (4) affords [Ru₃(CO)₇(μ-H)₂(μ-dppm)(μ₃-Se)] (5) in 85% yield. The molecular structures of 2 and 5 reveal that the diphosphine and one hydride simultaneously bridge the same ruthenium-ruthenium edge with the second hydride spanning one of the non-bridged edges. Both 2 and 5 are fluxional at room temperature being attributed to hydride migration between the non-bridged edges. Addition of HBF₄ to 2 affords the cationic trihydride [Ru₃(CO)₇(μ-H)₃(μ-dppm)(μ₃-S)][BF₄] (6) in which the hydrides are non-fluxional due to the blocking of the free ruthenium-ruthenium edge.     

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.     

First Examples of Electrophilic Addition to a Fe2Q Face of [Fe3(μ3-Q)(CO)9]2− (Q=Se, Te)—Synthesis and Characterisation of [MFe3(μ4-Q)(CO)9Cp*] and [IrFe2(μ3-Q)(CO)7Cp*] (M=Rh, Ir; Cp*=η5-C5(CH3)5)

The reaction of [Et₄N]₂[Fe₃(μ ₃-Q)(CO)₉] (Q=Se ([Et₄N]₂[1b]), Te ([Et₄N]₂[1c])) with [Cp*M(CH₃CN)₃][CF₃SO₃]₂ (M=Rh, Ir) leads to the addition of a Cp*M²⁺ unit to a Fe₂Q face of the initial cluster. In this way four new heteronuclear clusters [MFe₃(μ ₄-Q)(CO)₉Cp*] (M=Rh (2b, c); M=Ir (3b, c)) were obtained possessing a butterfly-shaped cluster core bridged by a μ ₄-Q unit. Furthermore, reaction with the Ir starting complex leads to the metal-substituted derivatives [IrFe₂(μ ₃-Q)(CO)₇Cp*] (4b, c) in lower yields, whose structures consist of a triangular metal core capped by a μ ₃-Q ligand. The products were comprehensively characterised by spectroscopic methods and the molecular structures of 2b, 3c, and 4c were established by single crystal X-ray diffraction measurements.     

Heterometallic heterochalcogenmethylarsenide clusters: Synthesis,molecular structures,and thermolysis

Reactions of the arsinechalcogenide complexes [Fe₃(μ₃-X)(μ₃-AsCH₃)(CO)₉] (X = Se (Ia) or Te (Ib)) with (PPh₃)₂Pt(PhC≡CPh) (transmetalation reaction) and Cp₂Cr₂(SCME₃)₂S (Cp = π-C₅H₅) (photochemical reaction) gave the heterometallic (heterochalcogen)(methylarsine) clusters [(PPh₃)₂Pt(μ₃-X)(μ₃-AsCH₃)Fe₂(CO)₆] (II and III, respectively), as well as Fe₃(μ₃-X)(μ₃-AsCH₃)(CO)₈(C₅H₅)₂Cr₂(μ₃-S)(μ₂-S ^t Bu)₂ (IV and V, respectively). The structures of complexes II, IV, and V were determined by X-ray diffraction analysis. Thermolysis of all the complexes yielded no metal carbides or oxides.     

Syntheses of new Mo(II) and W(II) mono(hydrosulfido) complexes and their conversion into di- and tetranuclear sulfido-bridged heterobimetallic complexes

Treatment of [Cp′MH(CO)₃] (M = Mo, W; Cp′ = η⁵-C₅H₅ (Cp), η⁵-C₅Me₅ (Cp*)) with 1/8 equiv of S₈ in THF, followed by the reaction with dppe under UV irradiation, gave new mono(hydrosulfido) complexes [Cp′M(SH)(CO)(dppe)] (Cp′ = Cp: M = Mo (5), W (6); Cp′ = Cp*: M = Mo (7), W (8); dppe = Ph₂PCH₂CH₂PPh₂). When 5 and 6 dissolved in THF were allowed to react with [RhCl(PPh₃)₃] in the presence of base, heterodinuclear complexes with bridging S and dppe ligands [CpM(CO)(μ-S)(μ-dppe)Rh(PPh₃)] (M = Mo (9), W(10)) were obtained. Semi-bridging feature of the CO ligands were also demonstrated. Upon standing in CH₂Cl₂ solutions, 9 and 10 were converted further to the dimerization products [(CpM)₂{Rh(dppe)}₂(μ₂-CO)₂(μ₃-S)₂] (M = Mo (13), W). Detailed structures of mononuclear 7 and 8, dinuclear 9 and tetranuclear 13 have been determined by the X-ray diffraction.     

Coordinating properties of [M(CO)5(CN)] [M=Cr; Mo; W] ligands: formation of ion pairs or dinuclear cyanide-bridged complexes, spectroscopic and X-ray diffraction studies

The reaction of sodium cyanopentacarbonylmetalates Na[M(CO)₅(CN)] (M=Cr; Mo; W) with cationic Fe(II) complexes [Cp(CO)(L)Fe(thf)][O₃SCF₃], [L=PPh₃ (1a), CN-Benzyl (1b), CN-2,6-Me₂C₆H₃ (1c); CN-Bu^t (1d), P(OMe)₃ (1e), P(Me)₂Ph (1f)] in acetonitrile solution, yielded the metathesis products [Cp(CO)(L)Fe(NCCH₃)][NCM(CO)₅] [M=W, L=PPh₃ (2a), CN-Benzyl (2b), CN-2,6-Me₂C₆H₃ (2c); CN-Bu^t (2d), P(OMe)₃ (2e), P(Me)₂Ph (2f); M=Cr, L=(PPh₃) (3a), CN-2,6-Me₂C₆H₃ (3c); M=Mo, L=(PPh₃) (4a), CN-2,6-Me₂C₆H₃ (4c)]. The ionic nature of such complexes was suggested by conductivity measurements and their main structural features were determined by X-ray diffraction studies. Well-resolved signals relative to the [M(CO)₅(CN)] moieties could be distinguished only when ¹³C NMR experiments were performed at low temperature (from −30 to −50 °C), as in the case of [Cp(CO)(PPh₃)Fe(NCCH₃)][NCW(CO)₅] (2a) and [Cp(CO)(Benzyl-NC)Fe(NCCH₃)][NCW(CO)₅] (2b). When the same reaction was carried out in dichloromethane solution, neutral cyanide-bridged dinuclear complexes [Cp(CO)(L)FeNCM(CO)₅] [M=W, L=PPh₃ (5a), CN-Benzyl (5b); M=Cr, L=(PPh₃) (6a), CN-2,6-Me₂C₆H₃ (6c), CO (6g); M=Mo, L=CN-2,6-Me₂C₆H₃ (7c), CO (7g)] were obtained and characterized by infrared and NMR spectroscopy. In all cases, the room temperature ¹³C NMR measurements showed no broadening of cyano pentacarbonyl signals and, relative to tungsten complexes [Cp(CO)(PPh₃)FeNCW(CO)₅] (5a) and [Cp(CO)(CN-Benzyl)FeNCW(CO)₅] (5b), the presence of ¹⁸³W satellites of the ¹³CN resonances (J_CW ∼ 95 Hz) at room temperature confirmed the formation of stable neutral species. The main ¹³C NMR spectroscopic properties of the latter compounds were compared to those of the linkage isomers [Cp(CO)(PPh₃)FeCNW(CO)₅] (8a) and [Cp(CO)(CN-Benzyl)FeCNW(CO)₅] (8b). The characterization of the isomeric couples 5a-8a and 5b-8b was completed by the analyses of their main IR spectroscopic properties. The crystal structures determined for 2a, 5a, 8a and 8b allowed to investigate the geometrical and electronic differences between such complexes. Finally, the study was completed by extended Hückel calculations of the charge distribution among the relevant atoms for complexes 2a, 5a and 8a.     

A quantum chemical study of the effect of phosphine ligand on the structure of the Mn and Fe vinylidene binuclear complex

Structures and relative energies of binuclear iron-manganese complexes with the phosphine ligand L, which exist in vinylidene Cp(CO)(L)MnFe(μ-C=CHPh)(CO)₄ (2) and benzylidene ketene η⁴-{C[Mn(CO)(L)Cp]? ?(CO)CHPh}Fe(CO)₃ (3) forms are calculated by the B3LYP density functional method. Four isomers with different positions of ligand L relative to the phenyl ring (conformers a and b) and the substituent Ph relative to the С=С bond (conformers E and Z) are considered for each form and their relative stability is determined. It is shown that all isomers of 2 have approximately the same energy (within 4 kcal/mol) whereas the energies of isomers of 3 differ within 21 kcal/mol. Isomer 3Ea in which the PPh₃ ligand contacts with the phenyl substituent of the vinylidene group is most energetically favorable. It is found that with an increase in the L ligand size in the order PH₃ < PH₂Ph < PHPh₂ < PPh₃ the Mn–P bond length increases to 2.37 Å in the most stable isomer of form 3 and to 2.43 Å in the isomers of 2 and three conformers of 3. A more substantial increase in the Mn–P bond length in complexes 2 and 3 correlates with their lower stability as compared to isomer Ea of 3, which is consistent with experimental data on the presence of only one conformer 3Ea in solution.     

Stannylene complexes of manganese,iron, and platinum

A number of stannylene complexes with different M: Sn ratios were obtained using various metals and substituents at the tin atom. The structures of the complexes were examined. A reaction of CpMn(CO)₂THF with (Ph₄As)⁺(SnCl₃)^? gave the ionic complex [Ph₄As]⁺[CpMn(CO)₂SnCl₃]^? (I). The action of C₆F₅MgBr on the complex C₅H₅Mn(CO)(NO)SnCl₃ produced C₅H₅Mn(CO)(NO)Sn(C₆F₅)₃ (II). Replacement of the Cl ions in the complex [CpFe(CO)₂]₂SnCl₂ by phenylacetylenide groups gave rise to the neutral complex [CpFe(CO)₂]₂Sn(C≡CPh)₂ (III). A reaction of (Dppm)PtCl₂ (Dppm is 1,1-bis(diphenylphosphino)methane) with SnCl₂ · 2H₂O in the presence of diglyme yielded the ionic complex [η³-CH₃O(CH₂)₂O(CH₂)₂OCH₃)SnCl]⁺[(η ²-Dppm)Pt(SnCl₃)₃]^? (IV). Transmetalation in a reaction of [(Dppe)₂CoCl][SnCl₃] · PhBr (Dppe is 1,2-bis(diphenylphosphino)ethane) with (Dcpd)PtCl₂ (Dcpd is dicyclopentadiene) in the presence of SnCl₂ afforded the ionic complex [Pt(Dppe)₂]₃[Pt(SnCl₃)₅]₂ (V). Structures I–V were identified by X-ray diffraction. In these structures, the formally single bonds between the atoms of transition metals M (Mn, Fe, and Pt) and Main Group heavy elements (Sn and P) having vacant d orbitals are appreciably shortened. The M-Sn bond length in complexes II and III are virtually independent of the substituents at the tin atom and the Pt-Sn bond length in complexes IV and V is virtually independent of the Pt: Sn ratio.