Synthesis and cleavage reactions of thiocarbonyl-bridged Cp2Fe2(CO)3CS,and preparation of the carbene complexes CpFe(CO)C(N2C2H6)SnPh3 and [CpFe(CO)2C(OMe)2]PF6

The thiocarbonyl-bridged complex Cp₂Fe₂(CO)₃CS is obtained by the reaction of CpFe(CO)₂^? and (PhO)₂CS in THF. Infrared and NMR spectra show that the compound exists in solution in interconverting cis and trans forms, but that the isomerization occurs more slowly than for the carbonyl analog [CpFe(CO)₂]₂. Most reagents which cleave [CpFe(CO)₂]₂, such as Br₂, HgCl₂, and O₂/HBF₄, do not give simple cleavage reactions with Cp₂Fe₂(CO)₃CS. Reductive cleavage of Cp₂Fe₂(CO)₃CS with Na(Hg) gives the thiocarbonyl anion CpFe(CO)(CS)^?, which reacts with Ph₃SnCl to form CpFe(CO)(CS)SnPh₃. Methylamine reacts with CpFe(CO)(CS)SnPh₃ to give CpFe(CO)(CNMe)SnPh₃, while ethylenediamine gives the carbene complexes CpFe(CO)C(N₂C₂H₆)SnPh₃. The preparation of another new carbene complex, [CpFe(CO)₂C(OMe)₂]PF₆, is also described.     

Multifunctional iron thiocarboxylate complexes: synthesis,reactivity and structure of CpFe(CO)<Subscript>2</Subscript>SCO-3,5-C<Subscript>6</Subscript>H<Subscript>4</Subscript>(COCl)<Subscript>2</Subscript>

A controlled substitution reaction of the chlorine atoms of 1,3,5-benzenetricarbonyl trichloride by the organoiron fragment (CpFe(CO)₂S) has been achieved. The complexes CpFe(CO)₂SCO-3,5-C₆H₃(COCl)₂ (1), 1,3-[CpFe(CO)₂SCO]₂-5-C₆H₃COCl (2) and 1,3,5-[CpFe(CO)₂SCO]₃C₆H₃ (3) were prepared from the reaction of (μ-S _x )[CpFe(CO)₂]₂ (x = 3, 4) with 1,3,5-C₆H₃(COCl)₃ in a 1:1, 2:1, or 3:1 metal to ligand molar ratio. The reactions of (1) with amines, thiols, and carboxylic acids produce the trifunctional mono-iron complexes CpFe(CO)₂SCO-3,5-C₆H₃(COY)₂ [Y = NR₂ (4), SR (5), OCOR (4)]. The X-ray structure determination of (1) is reported.     

Substituted iron selenocarboxylate complexes CpFe(CO)(EPh3)SeCOR (E = P,As, Sb)

Photolytic substitutions of iron selenocarboxylate complexes CpFe(CO)₂SeCOR with triphenylphosphine, triphenylarsine or triphenylantimony (EPh₃) gave exclusively the monosubstituted complexes CpFe(CO)(EPh₃)SeCOR [R = 3,5-C₆H₃(NO₂)₂ (1), 4-C₆H₄NO₂ (2), Ph (3), 2-C₆H₄Me (4), and E = P (a), As (b), Sb (c)] in high yields.     

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.     

Synthesis and biological study of a new series of bifunctional organoiron thio‐ and seleno‐terephthalate derivatives (C5H5)Fe(CO)2ECO(C6H4)COX (E = S,X = R2N,RNH, NH2, OH,Cl; E = Se,X = RNH,RS, RCOO,NH2, OH,Cl)

A new series of bifunctional organoiron thio‐ and seleno‐terephthalate complexes — (η‐C₅H₅)Fe(CO)₂ECO(C₆H₄)COX [E = S; X = C₆H₁₁NH, (C₂H₅)₂N; and E = Se; X = P? CH₃? C₆H₄? NH, C₆H₅? C₂N₂O? S, m? NO₂? C₆H₄? CH?CH? COO] — has been synthesized via the organic transformation reactions of the terephthaloyl chloride precursors η‐(C₅H₅)Fe(CO)₂ECO(C₆H₄)COCl with the desired nucleophiles. These new complexes were characterized by elemental analysis, IR and ¹H NMR spectra. The above complexes, in addition to some other selected analogues, were tested for their antifungal, antibacterial and mutagenic activity. Our results show that all the selenium‐containing compounds have antifungal activity on Candida albicans and antibacterial effects against Bacillus subtilis and Staphylococcus aureus. Four of the six selenium‐containing derivatives exhibited growth inhibitory effects against Pseudomonas aeruginosa and/or Escherichia coli. Sulfur‐containing derivatives elicited activity against C. albicans, and each one of them showed activity against at least one of the bacterial strains that have been used in this investigation. Two selenium‐ and two sulfur‐containing derivatives showed mutagenic activity against one or more than one strain of the Salmonella typhimurium using the Ames test. Copyright © 2001 John Wiley & Sons, Ltd.     

Zur Darstellung und Reaktivität von Tetraalkylcyclobutadienplatin(II)-Komplexen [PtCl2(C4R4)L]

Preparation and Reactivity of Platinumcyclobutadiene Complexes [PtCl₂(C₄R₄)L] H[PtCl₃(C₄H₈)], prepared by reduction of H₂[PtCl₆] with n-butanol reacts with 2-pentyne to give equal amounts of the regioisomers [PtCl₂(C₄Et₂Me₂)] ( 3 a, 3 b ). An equimolar mixture of 2-butyne/3-hexyne reacts under the same conditions to give [PtCl₂(C₄Me₄)] ( 1 ), [PtCl₂(C₄Et₄)] ( 2 ) and [PtCl₂(C₄Et₂Me₂)] ( 3 a ) in a molar ratio 1:1.3:6.6. 1 and 2 react with ligands L (L = py a , p-tol b , PPh₃ c , AsPh₃ d , SbPh₃ e ) to give complexes of the type [PtCl₂(C₄R₄)L]. The complexes were characterized by microanalysis as well as by i.r., ¹H- and ¹³C-n.m.r. spectroscopy.     

CpRu(CO)2(BF4) and [CpFe(CO)2(THF)]+ on mesoporous silica as adsorbents for the removal of dibenzothiophenes from hydrocarbon solutions

The complexes, CpRu(CO)2(BF4) and [CpFe(CO)2(eta2-2-methylpropene)][BF4], react with dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-Me2DBT) to give [CpRu(CO)2(DBT)][BF4] and [CpFe(CO)2(4,6-Me2DBT)][BF4], whose structures were established by X-ray diffraction studies. The same types of products are obtained when dibenzothiophenes react with CpRu(CO)2(BF4) and [CpFe(CO)2(THF)][BF4] that are adsorbed on the mesoporous silica SBA-15. DRIFT and XPS studies indicate that CpRu(CO)2(BF4) and [CpRu(CO)2(DBT)][BF4] are adsorbed on the SBA-15 by hydrogen-bonding of the BF4- anions to surface Si-O-H groups. CpRu(CO)2(BF4)/SBA-15 removes 99% of the DBT in a 45% toluene/55% hexanes simulated petroleum feedstock. This solid phase extractant is less successful for sterically-hindered 4,6-Me2DBT, as only 72% of it is removed. The results show that CpRu(CO)2(BF4) can be immobilized by adsorption on mesoporous silica and that it reacts with dibenzothiophenes in the adsorbed form, CpRu(CO)2(BF4)/SBA-15, in much the same way that it reacts in solution.     

Photochemisch initiierte oxidative spaltung von [C5H5Mo(CO)3]2; ein einfacher zugang zu kationischen komplexen des typs [C5H5Mo(CO)2L2]BF4

The MoMo bond in [C₅H₅Mo(CO)₃]₂ is cleaved by ferricenium cations in the presence of additional Group V ligands under photochemical radiation (λ_max > 300 nm). The mononuclear cationic complexes [C₅H₅Mo(CO)₂L₂]BF₄ (L = E(C₆H₅)₃, E = P, As, Sb, Bi; L₂ = [(C₆H₅)₂PCH₂]₂) are obtained in high yield.     

Reactivity Studies of Iridium Pyridylidenes [TpMe2Ir(C6H5)2(C(CH)3C(R)NH] (R=H,Me, Ph)

The reactivity of a series of iridium? pyridylidene complexes with the formula [Tp^Me2Ir(C₆H₅)₂(C(CH)₃C(R)N H] ( 1 a – 1 c ) towards a variety of substrates, from small molecules, such as H₂, O₂, carbon oxides, and formaldehyde, to alkenes and alkynes, is described. Most of the observed reactivity is best explained by invoking 16 e^? unsaturated [Tp^Me2Ir(phenyl)(pyridyl)] intermediates, which behave as internal frustrated Lewis pairs (FLPs). H₂ is heterolytically split to give hydride? pyridylidene complexes, whilst CO, CO₂, and H₂C?O provide carbonyl, carbonate, and alkoxide species, respectively. Ethylene and propene form five‐membered metallacycles with an IrCH₂CH(R)N (R=H, Me) motif, whereas, in contrast, acetylene affords four‐membered iridacycles with the IrC(?CH₂)N moiety. C₆H₅(C?O)H and C₆H₅C?CH react with formation of Ir? C₆H₅ and Ir? C?CPh bonds and the concomitant elimination of a molecule of pyridine and benzene, respectively. Finally the reactivity of compounds 1 a – 1 c against O₂ is described. Density functional theory calculations that provide theoretical support for these experimental observations are also reported.     

Bisphosphoranylacetylene und der Cobaltkomplex Co2(CO)6{[(C2H5)2N]2PF2CCPF2[N(C2H5)2]2}

Bisphosphoranylacetylenes and the Cobalt Complex Co₂(CO)₆{[(C₂H₅)₂N]₂PF₂C?CPF₂[N(C₂H₅)₂]₂} Synthesis and properties of bis[difluorobis(diethylamino)phosphoranyl]acetylene, 2 , bis(difluorodimorpholinophosphoranyl)acetylene, 4 , and bis(trifluorodiethylaminophosphoranyl)-acetylene, 6 , are described. With Co₂(CO)₈ 2 forms the coordination compound hexacarbonyl-μ-η-bis-[difluorobis(diethylamino)phosphoranyl]acetylene-dicobalt(Co? Co), 7 . The results of the X-ray structural analysis of 2 and 7 are reported.     

Synthese und Struktur der Phosphor-verbrückten Übergangsmetallkomplexe [Fe2(CO)6(PR)6] (R = tBu,iPr), [Fe2(CO)4(PiPr)6], [Fe2(CO)3Cl2(PtBu)5], [Co4(CO)10(PiPr)3], [Ni5(CO)10(PiPr)6] und [Ir4(C8H12)4Cl2(PPh)4]

Synthesis and Structure of the Phosphorus-bridged Transition Metal Complexes [Fe₂(CO)₆(PR)₆] (R = ^tBu, ⁱPr), [Fe₂(CO)₄(PⁱPr)₆], [Fe₂(CO)₃Cl₂(P^tBu)₅], [Co₄(CO)₁₀(PⁱPr)₃], [Ni₅(CO)₁₀(PⁱPr)₆], and [Ir₄(C₈H₁₂)₄Cl₂(PPh)₄] (P^tBu)₃ and (PⁱPr)₃ react with [Fe₂(CO)₉] to form the dinuclear complexes [Fe₂(CO)₆(PR)₆] (R = ^tBu: 1 ; ⁱPr: 2 ). 2 is also formed besides [Fe₂(CO)₄(PⁱPr)₆] ( 3 ) in the reaction of [Fe(CO)₅] with (PⁱPr)₃. When PⁱPr(P^tBu)₂ and PⁱPrCl₂ are allowed to react with [Fe₂(CO)₉] it is possible to isolate [Fe₂(CO)₃Cl₂(P^tBu)₅] ( 4 ). The reactions of (PⁱPr)₃ with [Co₂(CO)₈] and [Ni(CO)₄] lead to the tetra- and pentanuclear clusters [Co₄(CO)₁₀(PⁱPr)₃] ( 5 ), [Ni₄(CO)₁₀(PⁱPr)₆] [2] and [Ni₅(CO)₁₀(PⁱPr)₆] ( 6 ). Finally the reaction of [Ir(C₈H₁₂)Cl]₂ with K₂(PPh)₄ leads to the complex [Ir₄(C₈H₁₂)₄Cl₂(PPh)₄] ( 7 ). The structures of 1–7 were obtained by X-ray single crystal structure analysis (1: space group P2₁/c (Nr. 14), Z = 8, a = 1 758.8(16) pm, b = 3 625.6(18) pm, c = 1 202.7(7) pm, β = 90.07(3)°; 2 : space group P1 (Nr. 2), Z = 1, a = 880.0(2) pm, b = 932.3(3) pm, c = 1 073.7(2) pm, α = 79.07(2)°, β = 86.93(2)°, γ = 72.23(2)°; 3 : space group Pbca (Nr. 61), Z = 8, a = 952.6(8) pm, b = 1 787.6(12) pm, c = 3 697.2(30) pm; 4 : space group P2₁/n (Nr. 14), Z = 4, a = 968.0(4) pm, b = 3 362.5(15) pm, c = 1 051.6(3) pm, β = 109.71(2)°; 5 : space group P2₁/n (Nr. 14), Z = 4, a = 1 040.7(5) pm, b = 1 686.0(5) pm, c = 1 567.7(9) pm, β = 93.88(4)°; 6 : space group Pbca (Nr. 61), Z = 8, a = 1 904.1(8) pm, b = 1 959.9(8) pm, c = 2 309.7(9) pm. 7 : space group P1 (Nr. 2), Z = 2, a = 1 374.4(7) pm, b = 1 476.0(8) pm, c = 1 653.2(9) pm, α = 83.87(4)°, β = 88.76(4)°, γ = 88.28(4)°).     

Addition des O'Donnell Reagenzes [Ph2C=NCHCO2Me]– an π-koordinierte,ungesättigte Kohlenwasserstoffe in [(C6H7)Fe(CO)3]+, [(C7H9)Fe(CO)3]+, [(C7H7)M(CO)3]+ (M = Cr,Mo) und [(C2H4)Re(CO)5]+. α-Aminosäuren mit metallorganischen Seitenketten

Metal Complexes of Biologically Important Ligands. CXVII [1] Addition of the O'Donnell Reagent [Ph₂C=NCHCO₂Me]^– to Coordinated, Unsaturated Hydrocarbons of [(C₆H₇)Fe(CO)₃]⁺, [C₇H₉Fe(CO)₃]⁺, [(C₇H₇)M(CO)₃]⁺ (M = Cr, Mo), and [(C₂H₄)Re(CO)₅]⁺. α-Amino Acids with Organometallic Side Chains The addition of [Ph₂C=NCHCO₂Me]^– to [(C₆H₇)Fe(CO)₃]⁺, [(C₇H₉)Fe(CO)₃]⁺, [(C₇H₇)M(CO)₃]⁺ (M = Cr, Mo) and [(C₂H₄)Re(CO)₅]⁺ gives derivatives of α-amino acids with organometallic side chains. The structure of [(η⁴-C₆H₇)CH(N=CPh₂)CO₂Me]Fe(CO)₃ was determined by X-ray diffraction. From the adduct of [Ph₂C=NCHCO₂Me]^– and [(C₇H₇)Mo(CO)₃]⁺ the Schiff base of a new unnatural α-amino acid, Ph₂C=NCH(C₇H₇)CO₂Me, was obtained.     

Insight into the structures of [M(C5H4I)(CO)3] and [M2(C12H8)(CO)6] (M = Mn and Re) containing strong I...O and π(CO)–π(CO) interactions

The compounds tricarbonyl(η⁵‐1‐iodocyclopentadienyl)manganese(I), [Mn(C₅H₄I)(CO)₃], (I), and tricarbonyl(η⁵‐1‐iodocyclopentadienyl)rhenium(I), [Re(C₅H₄I)(CO)₃], (III), are isostructural and isomorphous. The compounds [μ‐1,2(η⁵)‐acetylenedicyclopentadienyl]bis[tricarbonylmanganese(I)] or bis(cymantrenyl)acetylene, [Mn₂(C₁₂H₈)(CO)₆], (II), and [μ‐1,2(η⁵)‐acetylenedicyclopentadienyl]bis[tricarbonylrhenium(I)], [Re₂(C₁₂H₈)(CO)₆], (IV), are isostructural and isomorphous, and their molecules display inversion symmetry about the mid‐point of the ligand C[triple‐bond]C bond, with the (CO)₃M(C₅H₄) (M = Mn and Re) moieties adopting a transoid conformation. The molecules in all four compounds form zigzag chains due to the formation of strong attractive I...O [in (I) and (III)] or π(CO)–π(CO) [in (I) and (IV)] interactions along the crystallographic b axis. The zigzag chains are bound to each other by weak intermolecular C—H...O hydrogen bonds for (I) and (III), while for (II) and (IV) the chains are bound to each other by a combination of weak C—H...O hydrogen bonds and π(Csp²)–π(Csp²) stacking interactions between pairs of molecules. The π(CO)–π(CO) contacts in (II) and (IV) between carbonyl groups of neighboring molecules, forming pairwise interactions in a sheared antiparallel dimer motif, are encountered in only 35% of all carbonyl interactions for transition metal–carbonyl compounds.     

Darstellung von Tetracarbonyl-triphenylphosphinmanganorganoplumbanen R4−nPb[Mn(CO)4P(C6H5)3]n (RCH3, C6H5; n = 1,2)

Preparation of R_4?nPb[Mn(CO)₄P(C₆H₅)₃]_n Compounds (R?CH₃, C₆H₅; n = 1, 2) As the first examples of organolead manganese carbonyls substituted in the manganese carbonyl ligand compounds of the type R_4?nPb[Mn(CO)₄P(C₆H₅)₃]_n (R?CH₃, C₆H₅; n = 1, 2) have been prepared by the alkali salt method from R_4?nPbCl_n and NaMn(CO)₄P(C₆H₅)₃. (C₆H₅)₂Sn[Mn(CO)₄P(C₆H₅)₃]₂ has been gained by the same method and also by thermal ligand exchange. According the IR data the ligand P(C₆H₅)₃ is trans to the tetrahedrally surrounded lead. In solution to compounds are monomeric.     

Mono- and bi-iron chalcogenocarboxylate complexes

A series of thiocarboxylato and selenocarboxylato monomeric CpFe(CO)₂ECORCOCl and dimeric [CpFe(CO)₂ECO]₂R iron complexes have been synthesized and characterized. The interaction of (μ-E_x)[CpFe(CO)₂]₂ (E = S; x = 2–4. E = Se; x = 1) with di-acid chlorides (ClCORCOCl) in a 1:1 molar ratio gave the monomeric complexes CpFe(CO)₂ECORCOCl for R = 1,3-C₆H₄, 2,6-C₅H₃N, 1,2-C₆H₄. However, the dimeric complexes [CpFe(CO)₂ECO]₂R were obtained from the same reactants in a 2:1 metal-to-ligand molar ratio in which R is 1,3-C₆H₄, 2,6-C₅H₃N or C₂H₄. The monomer versus dimer production mainly depends on the electronic and steric factors of the R-moiety. The new monomeric and dimeric thio- and selenocarboxylato iron complexes have been characterized by spectroscopic techniques (¹H- and ¹³C-NMR, IR) and by elemental analysis. The structures of [CpFe(CO)₂SCO]₂(1,3-C₆H₄) and its seleno analogue [CpFe(CO)₂SeCO]₂(1,3-C₆H₄) were determined by X-ray structure determination.     

Heteronukleare Metallatomcluster der Typen X4−n[SnM(CO)4P(C6H5)3]n und M2(CO)8 [μ-Sn(X)M (CO)4P(C6H5)3]2 aus Umsetzungen von SnX2 mit M2(CO)8[P(C6H5)3]2 (X = Halogen; M = Mn,Re; n = 2, 3)

Heteronuclear Metal Atom Clusters of the Types X_4?n[SnM(CO)₄P(C₆H₅)₃]_n and M₂(CO)₈[μ-Sn(X)M(CO)₄P(C₆H₅)₃]₂ by Reaction of SnX₂ with M₂(CO)₈[P(C₆H₅)₃]₂ (X = Halogene; M = Mn, Re; n = 2, 3) The compounds of the both types X_4?n[SnM(CO)₄P(C₆H₅)₃]_n (n = 3; M = Mn; X = F, Cl, Br, I. n = 2: M = Mn, Re; X = Cl, Br, I) and M₂(CO)₈[μ-Sn(X)M(CO)₄P(C₆H₅)₃]₂ (M = Mn; X = Cl, I. M = Re; X = Cl, Br, I) are prepared by reaction of SnX₂ with M₂(CO)₈[P(C₆H₅)₃]₂ (M = Mn, Re). Their IR frequencies are assigned. In Re₂(CO)₈[μ-Sn(Cl)Re(CO)₄P(C₆H₅)₃]₂ the central molecule fragment contains a planar Re₂Sn₂ rhombus with a transannular Re? Re bond of 316.0(2) pm. Each of the Sn^IV atoms is connected with the terminal ligands Cl and Re(CO)₄P(C₆H₅)₃. These ligands are in transposition with respect to the Re₂Sn₂ ring. The mean values for the remaining bond distances (pm) are: Sn? Re = 274.0(3); Sn? Cl = 243(1), Re? C = 176(5), Re? P = 242.4(9), C? O = 123(5). The factors with an influence on the geometrical shape of such M₂Sn₂ rings (M = transition metal) are discussed.     

Bariumstannat‐Pulver durch hydrothermale Synthese und durch Thermolyse von Bariumzinn(IV)‐glykolaten. Synthese und Struktur von [Ba(C2H6O2)4][Sn(C2H4O2)3] und [Ba(C2H6O2)2][Sn(C2H4O2)3]·CH3OH

Barium Stannate Powders from Hydrothermal Synthesis and by Thermolysis of Barium‐Tin(IV)‐Glycolates. Synthesis and Structure of [Ba(C₂H₆O₂)₄][Sn(C₂H₄O₂)₃] and [Ba(C₂H₆O₂)₂][Sn(C₂H₄O₂)₃]·CH₃OH The hydrothermal reaction as well as the microwave assisted hydrothermal reaction of SnO₂·aq with barium hydroxide gives Ba[Sn(OH)₆] ( 1 ) as powder with bar like particles. Compound 1 of the same morphology can also be isolated from a hydrothermal reaction of [Ba(C₂H₆O₂)₄][Sn(C₂H₄O₂)₃] ( 3 ). The reaction of SnO₂·aq with Ba(OH)₂·8H₂O in ethylene glycol yields the glycolate [Ba(C₂H₆O₂)₄][Sn(C₂H₄O₂)₃] ( 3 ), which forms in methanol the solvate [Ba(C₂H₆O₂)₂][Sn(C₂H₄O₂)₃]·CH₃OH ( 4 ). Compounds 1 , 3 and 4 react at different temperatures to BaSnO₃ ( 2 ) consisting of powders with different morphologies; because of the grain size of the resulting powders compounds 3 and 4 are suitable as precursor for the fabrication of corresponding ceramics.     

Reaction of Os3H2(CO)9(C6H4) with diphenylacetylene: the formation and structural characterisation of Os3(CO)7(C6H4)[PhCC(H)Ph]2

The reaction of the 'benzyne' cluster Os₃H₂(CO)₉(C₆H₄) with diphenylacetylene affords the new compound Os₃(CO)₇(C₆H₄)[PhCC(H)Ph]₂; a single crystal X-ray analysis of this product shows that two PhCC(H)Ph units and the benzyne moiety are bonded to the Os₃ core as separate ligands, and that under these conditions there is no ligand condensation.     

Metallkomplexe von Phenylenbistriazeniden: Synthese und Kristallstrukturen von [Cp(CO)2M]2(1,2-PhN3C6H4N3Ph) (M = Mo,W)

Metal Complexes of Phenylenebistriazenides: Synthesis and Crystal Structures of [Cp(CO)₂M]₂(1,2-PhN₃C₆H₄N₃Ph) (M = Mo, W) [Cp(CO)₂M]₂(1,2-PhN₃C₆H₄N₃Ph) [(M = Mo( 1 ), M = W( 2 )] is formed in the reaction of Cp(CO)₃MCl with PhN₃(H)C₆H₄N₃(H)Ph and C₂H₅ONa in a THF/ethanol mixture. 1 crystallizes from toluene as dark red crystals (triclinic, P1 , a = 1 499.3(9) pm, b = 1 734.0(7) pm, c = 1 852.8(8) pm, α = 66.84(3)°, β = 78.25(4)°, γ = 77.19(4)°). The unit cell contains four complexes with two independent complexes in the asymmetric unit, and eight solvent molecules. 2 crystallizes from THF as yellow crystals free from solvent molecules (triclinic, P1 , a = 979.0(5) pm, b = 1 152.8(5) pm, c = 1 475.8(5) pm, α = 98.26(4)°, β = 104.93(4)°, γ = 101.03(4)°, Z = 2). 1 and 2 are discrete molecular complexes with a 1,2-bis(phenyltriazenido)phenylligand, (PhN₃C₆H₄N₃Ph)^2?, chelating the metal atoms of two Cp(CO)₂M units with the N atoms N1 and N3 of both N₃ groups. Due to the sterical pretension of the Cp(CO)₂M units the phenylenebistriazenido ligand deviates strongly from planarity that is found in the metal complexes characterized so far.     

Theoretical Study of the Solvent Effect on the Electronic and Vibrational Properties of [CpFe(CO)<Subscript>2</Subscript>(NCS)] and [CpFe(CO)<Subscript>2</Subscript>(SCN)] Linkage Isomers

The present study illustrates the stability of [CpFe(CO)₂(NCS)] and [CpFe(CO)₂(SCN)] linkage isomers by the use of MPW1PW91 quantum method in the gas and solution phases. Our results reveal that the [CpFe(CO)₂(NCS)] isomer is more stable than the [CpFe(CO)₂(SCN)] isomer. Based on the polarizable continuum model, the effect of the solvent polarity on the stability, structural parameters, frontier orbital energies, and vibrational modes of carbonyl ligands (ν_CO) of these linkage complexes is explored. The molecular orbital analysis suggests that the major contributions to HOMO and LUMO arise from the ambidentate ligand and Fe in two isomers, respectively. In addition, the bonding interaction between the CpFe(CO)₂ fragment and the ambidentate ligand is studied by means of the energy decomposition analysis. The back-bonding effect in Fe–CO bonds is revealed in the calculation of the quadrupole polarization of the carbon atom by the QTAIM analysis. The character of Fe–N and Fe–S bonds in these complexes is analyzed by the natural bond orbital analysis.