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.     

Thiolate-bridged heterometallic complexes of manganese and platinum: Synthesis and molecular structures of (CO)4Mn(μ-SPh)Pt(PPh3)2, (CO)3(PPh3)Mn(μ-SPh)Pt(PPh3)(CO), and (CO)3Mn(μ-SPh)Pt(PPh3)(Dppm)

A reaction of the dimer [Mn(CO)₄(SPh)]₂ with (PPh₃)₂Pt(C₂Ph₂) gave the heterometallic complex (CO)₄Mn(μ-SPh)Pt(PPh₃)₂ (I) and its isomer (CO)₃(PPh₃)Mn(μ-SPh)Pt(PPh₃)(CO) (II). A reaction of complex I with a diphosphine ligand (Dppm) yielded the heterometallic complex (CO)₃Mn(μ-SPh)Pt(PPh₃)(Dppm) (III). Complexes I–III were characterized by X-ray diffraction. In complex I, the single Mn-Pt bond (2.6946(3) ?) is supplemented with a thiolate bridge with the shortened Pt-S and Mn-S bonds (2.3129(5) and 2.2900(6) ?, respectively). Unlike complex I, in complex II, one phosphine group at the Pt atom is exchanged for one CO group at the Mn atom. The Mn-Pt bond (2.633(1) ?) and the thiolate bridge (Pt-S, 2.332(2) ?; Mn-S, 2.291(2) ?) are retained. In complex III, the Mn-Pt bond (2.623(1) ?) is supplemented with thiolate (Pt-S, 2.341(2) ?; Mn-S, 2.292(2) 0?) and Dppm bridges (Pt-P, 2.240(1)?; Mn-P, 2.245(2) ?). Apparently, the Pt atom in complexes I–III is attached to the formally double bond , as in Pt complexes with olefins.     

对苯二甲酸二丙炔醇酯与Co2(CO)8、Mo2Cp2(CO)4和RuCo2(CO)11的反应

室温下对苯二甲酸二丙炔醇酯分别与Co2CO8Mo2Cp2CO4和RuCo2CO11反应得到三个有机金属化合物C6H4pCO2CH2C2Hμ2Co2CO621、C6H4pCO2CH2C2H2RuCo2CO922和HC2CH2OCOC6H4pCO2CH2C2HμMo2Cp2CO43。研究发现三种金属核对端炔氢的屏蔽作用依次为RuCo2CO9>Co2CO6>Mo2CO4Cp2。化合物1的晶体衍射发现属三斜晶系空间群a=8.1392b=8.8083c=11.3433β=96.2606°V=773.443Z=1Dc=1.748g·cm-3R=0.0513wR=0.1266。     

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.     

Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with toluene

The heteronuclear cluster RuOs₃(μ-H)₂(CO)₁₃ (4) reacts with refluxing toluene to form the clusters Ru₂Os₃(μ-H)₂(CO)₁₆ (5) RuOs₃(CO)₉(μ-CO)₂(η⁶-C₆H₅Me) (6) and Ru₂Os₃(CO)₁₂(μ-CO)(η⁶-C₆H₅Me) (7). Cluster 5 exists as a mixture of five isomers. The inter-relationship among the clusters has also been investigated.     

Reactivity of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with indene

The heteronuclear cluster RuOs₃(μ-H)₂(CO)₁₃ (1) reacts with indene under thermal activation to afford the novel clusters RuOs₃(μ-H)(CO)₉(μ-CO)₂(η⁵-C₉H₇) (3), RuOs₃(μ-H)(CO)₉(μ₃,η⁵:η²:η²-C₉H₇) (4) and Ru₂Os₃(μ-H)(CO)₁₁(μ₃,η⁵:η²:η²-C₉H₇) (5), the latter two possessing indenyl ligands in the μ₃,η⁵:η²:η² bonding mode. Cluster 5 exists as a mixture of two isomers. The inter-relationship among the clusters has also been investigated.     

Ditertiary phosphine derivatives of the heteronuclear cluster RuOs3(μ-H)2(CO)13

The heteronuclear cluster RuOs₃(μ-H)₂(CO)₁₃ (1) reacted readily with a number of ditertiary phosphines under chemical activation with trimethylamine-N-oxide. The solid-state and solution structures of these derivatives have been examined. Six structural types have been characterized crystallographically, including one in which a phenyl group migrates from the ditertiary phosphine ligand to the metal framework. There are many more isomers present in solution, most of which are rapidly inter-converting via hydride migrations.     

Synthesis and molecular structure of [((CO)3RuBr2)2(μ-SePh)2Ru(CO)4] cluster with a Ru3Se2 chain core

Treatment of ruthenium carbonyl, [Ru₃(CO)₁₂] with phenylseleno tribromide PhSeBr₃ afforded a new triruthenium cluster, [(CO)₁₀Br₄Ru₃(μ-SePh)₂] (1). Its molecular structure was determined by single crystal XRD method (P2₁/c; a = 10.514(3) Å; b = 10.814(3) Å; c = 19.063(5) Å; β = 105.064(4)°; V = 2093.1(10) Å³) and shown to have two lateral Ru(CO)₃Br₂ units attached via two PhSe bridges to a Ru(CO)₄ center forming a chain-like Ru-Se-Ru-Se-Ru cluster core. This is in contrast with a recently reported reaction of PhTeBr₃ with [Ru₃(CO)₁₂] which formed a monomeric complex of ruthenium-dicarbonyl-dibromo fragment coordinating two PhTeBr ligands, [(CO)₂RuBr₂(PhTeBr)₂].     

Synthesis,structure characterization and thermal properties of [Zr6(μ3-O)4(μ3-OH)4(OOCCH2Bu)9(μ2-OH)3]2

Oxo/hydoxo zirconium(IV) complex of the general formula [Zr₆(μ₃-O)₄(μ₃-OH)₄(OOCCH₂^tBu)₉(μ₂-OH)₃]₂ has been isolated, when Zr(OⁱPr)₄ reacted with a 2-fold excess of 3,3-dimethylbutyric acid. Single crystal X-ray diffraction data, collected at 103 and 153 K, showed that the studied compound crystallizes in hexagonal system (P6₃/m (no. 176)). Structure consists of dimers composed of [Zr₆(μ₃-O)₄(μ₃-OH)₄(OOCCH₂^tBu)₉] sub-units, linked by six μ₂-OH bridges. Infrared spectroscopic studies proved the presence of hydroxo groups in the structure of studied clusters and formation of different types of oxo/hydroxo bridges. The application of variable temperature infrared spectroscopy and differential scanning calorimetry revealed that the structure of this complex undergoes the phase transitions at 143–183 and 203–293 K. Comparison of spectral and crystallographic data suggests that these phase transitions might be related to changes in the strength of Zr–O bonds of μ₂-OH bridges linking complex sub-units, and change in symmetry of the crystal lattice (from hexagonal to trigonal). Analysis of thermogravimetric data showed that decomposition of [Zr₆(μ₃-O)₄(μ₃-OH)₄(OOCCH₂^tBu)₉(μ₂-OH)₃]₂ proceeds with complete conversion to ZrO₂ (monoclinic form) between 603 and 803 K.     

Phenyltellurenyl halide complexes of ruthenium and rhenium (CO)2RuBr2(PhTeBr)2 and (CO)3Re(PhTeI)3(μ3-I): Synthesis and crystal and molecular structures

Reactions of Ru₃(CO)₁₂ with PhTeBr₃ and of Re(CO)₅Cl with PhTeI in benzene give the stable complexes (CO)₂RuBr₂(PhTeBr)₂ (I) and (CO)₃Re(PhTeI)₃(μ³-I) (II) containing two and three ligands PhTeX (X = Br or I), respectively. The bonds between these ligands and the central metal atom are fairly shortened (on average, Ru-Te, 2.608 ?; Re-Te, 2.7554(12)-2.7634(13) ?). The Te-X bonds in the ligands PhTeBr (2.5163(5) ?) and PhTeI (2.7893(15) ?) are not lengthened appreciably. In complex II, the iodide anion is not coordinated by rhenium, yet being attached through weak secondary bonds to three Te atoms of the three ligands PhTeI.     

Disulfido iron-manganese carbonyl cluster complexes: Synthesis, structure, bonding and properties of the radical CpFeMn2(CO)7(μ3-S2)2

Two new compounds CpFeMn₂(CO)₇(μ₃-S₂)₂ (2) and Cp₃Fe₃Mn(CO)₄(μ₃-S₂)₂(μ₃-S) (3) were obtained by the treatment of [CpFeMn(CO)₅(μ₃-S₂)]₂ (1) with CO at room temperature in the presence of room light. Compound 2 contains two triply bridging disulfido ligands on opposite sides of an open FeMn₂ triangular cluster. EPR and temperature-dependent magnetic susceptibility measurements show that it is paramagnetic with one unpaired electron per formula equivalent. The electronic structure of 2 was established by DFT and Fenske-Hall (FH) molecular orbital calculations which show that the unpaired electron occupies a low lying antibonding orbital that is located principally on the iron atom. The cyclic voltammogram of 2 exhibits one reversible one-electron oxidation wave at +0.34 V and one irreversible one-electron reduction wave at −0.66 V vs. Ag/AgCl. Compound 3 contains three iron atoms and one manganese atom with two triply bridging disulfido ligands and one triply bridging sulfido ligand and has no unpaired electrons. The molecular structures of compounds 2 and 3 were established by single crystal X-ray diffraction analyses.     

Relativistic scalar and spin-orbit density functional calculations of the electronic structure, NICS index and ELF function of the [Re2(CO)8(μ-BiPh)2] and [Re2(CO)8(μ-BiPh2)2] clusters

Relativistic scalar and spin-orbit density functional calculations of the electronic structure, Nucleus-Independent Chemical Shift (NICS) index and ELF function of the [Re₂(CO)₈(μ-BiPh)₂] and [Re₂(CO)₈(μ-BiPh₂)₂] clusters are reported. We show here that the [Re₂(CO)₈(μ-BiPh)₂] cluster has large negative NICS values in the region defined by the Re-Bi-Re-Bi four-membered ring and the ELF function shows significant electron delocalization density in the center of the metallic ring, thus indicating an aromatic cluster. In contrast the Re-Bi-Re-Bi four-membered ring in the [Re₂(CO)₈(μ-BiPh₂)₂] cluster has negligible paratropic ring currents and the ELF function shows a low-density region within the metallic ring indicating that aromaticity is switched off. However, the phenyl ligands in both clusters show the expected aromatic character.     

Synthesis and crystal structure of new one-dimensional copper(II) complex [Cu4(En)2(μ1,1-N3)4(μ1,1,1-N3)2(μ1,3-N3)2]n

A new polymer azido-bridged copper(II) complex [Cu₄(En)₂(μ_1,1-N₃)₄(μ_1,1,1-N₃)₂(μ_1,3-N₃)₂] _n (I) (En = ethylenediamine) has been synthesized and crystallography characterized. Complex I shows one-dimensional coordination polymeric structure based on a tetranuclear cluster unit [Cu₄(En)₂(μ_1,1-N₃)₄(μ_1,1,1-N₃)₂(μ_1,3-N₃)₂], in which the azido ions display three different bridging modes.     

Synthesis and characterization of the cluster complexes containing tetrahedral FeCrCo(μ3-S) cluster cores generated by isolobal displacement reactions. Crystal structures of (η-RC5H4)FeCrCo(μ3-S)(CO)8 (R=H, CO2Et) and FeCo2(μ3-S)2(CO)9

The monoanions (η⁵-RC₅H₄)(CO)₃Cr⁻ (1, R=H; 2, R=Me; 3, R=CO₂Et) reacted with tetrahedral cluster FeCo₂(μ₃-S)(CO)₉ to give single isolobal displacement products (η⁵-RC₅H₄)FeCrCo(μ₃-S)(CO)₈ (4, R=H; 5, R=Me; 6, R=CO₂Et) in 86-89% yields, whereas monoanion (η⁵-RC₅H₄)(CO)₃Cr⁻ (7, R=C(O)Me) reacted with FeCo₂(μ₃-S)(CO)₉ to afford the expected single isolobal displacement product (η⁵-RC₅H₄)FeCrCo(μ₃-S)(CO)₈ (8, R=C(O)Me) in 5% yield and an unexpected square pyramidal cluster FeCo₂(μ₃-S)₂(CO)₉ (9) in 45% yield. Similarly, the dianions [η⁵-C₅H₄CH₂(CH₂OCH₂)_nCH₂C₅H₄-η⁵][(CO)₃Cr⁻]₂ (10, n=1; 11, n=2; 12, n=3) reacted with two molecules of FeCo₂(μ₃-S)(CO)₉ to produce double isolobal displacement products [η⁵-C₅H₄CH₂(CH₂OCH₂)_nCH₂C₅H₄-η⁵][FeCrCo(μ₃-S)(CO)₈]₂ (13, n=1; 14, n=2; 15, n=3) in 32-36% yields, while treatment of dianion [η⁵-C₅H₄C(O)CH₂]₂[(CO)₃Cr⁻]₂ (16) with two molecules of FeCo₂(μ₃-S)(CO)₉ gave the unexpected square pyramidal cluster FeCo₂(μ₃-S)₂(CO)₉ (9) in 42% yield and the corresponding double isolobal displacement product [η⁵-C₅H₄C(O)CH₂]₂[FeCrCo(μ₃-S)(CO)₈]₂ (17) in 8% yield. Products 4-6, 8, 9, 13-15 and 17 were characterized by elemental analyses, IR and ¹H NMR spectroscopy, as well as for 4, 6 and 9 by X-ray diffraction techniques.     

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.     

Solid-state cis-trans isomerization reaction of (η-MeC5H4)W(CO)2P(OPr)3I

cis-(η⁵-MeC₅H₄)W(CO)₂P(OⁱPr)₃I (1) was converted to the trans isomer 2 in the solid state (90-110 °C). The reaction was monitored by heating 1 in NMR tubes for periods of time (2-60 min), cooling the tubes to room temperature and determining the conversion by solution ³¹P and ¹H NMR spectroscopy. The data were consistent with a first-order reaction and yielded an activation energy of 59 ± 3 kJ mol⁻¹. Comparative kinetic data were obtained from an in situ analysis of a powder-XRD study of 1. The powder-XRD study was conducted at 80-100 °C (10-60 min), yielding an activation energy of 52 ± 2 kJ mol⁻¹ (first-order reaction). The reaction could not be monitored by single crystal X-ray diffraction as the crystal disintegrated over time on heating. This disintegration process was monitored by optical microscopy and revealed that while the bulk crystal morphology was retained the crystal surface roughened with time. The compounds 1 and 2 were also structurally characterised by X-ray crystallographic techniques.     

An anionic binuclear complex of tungsten(II), [(μ-Cl)3{W(SnCl3)(CO)3}2], and its reactivity towards norbornene

An anionic binuclear complex of tungsten(II), [(μ-Cl)₃{W(SnCl₃)(CO)₃}₂]⁻ (1⁻), containing the protonated piperidine molecule [Hpip]⁺ as the counter ion, has been obtained during crystallization of the product from reaction between [W(CO)₄(pip)₂] and SnCl₄ in dichloromethane solution, and its molecular structure has been elucidated by single-crystal X-ray diffraction studies. The chemical properties of complex 1 were investigated by IR and NMR spectroscopy in solution and its catalytic activity was checked in reaction with norbornene (NBE). In the presence of complex 1, NBE transformed to a new olefin, 2,2′-binorbornylidene with ca. 50% yield in dichloromethane solution. The spectroscopic characteristics of complex 1⁻ were compared with those of the reinvestigated analogue compound [(μ-Cl)₃W₂(SnCl₃)(CO)₇] (2). The ¹¹⁹Sn and ¹³C NMR data indicated that in dichloromethane solution complex 2 transformed to the ionic complex 1⁻.     

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.     

Nitrosyl derivatives of the unsaturated dihydrides [Mn2(μ-H)2(CO)6(μ-L2)] (L2 = Ph2PCH2PPh2, (EtO)2POP(OEt)2)

The title dimanganese complexes react with NO (5% in N₂) at room temperature to give as major products the corresponding hexanitrosyl derivatives [Mn₂(NO)₆(μ-L₂)] in moderate yields, and they react rapidly with NO₂ to give the corresponding hydride derivatives [Mn₂(μ-H)(μ-NO₂)(CO)₆(μ-L₂)], these having a nitrite ligand bridging the dimetal centre through the N and O atoms. The dppm-bridged dihydride also reacts selectively at 273 K with (PPN)NO₂ to give first the nitro derivative (PPN)[Mn₂(μ-H)(H)(NO₂)(CO)₆(μ-dppm)], which then transforms into the nitrosyl complex (PPN)[Mn₂(μ-CO)(CO)₅(NO)(μ-dppm)] at room temperature or above (dppm = Ph₂PCH₂PPh₂; PPN⁺ = [N(PPh₃)₂]⁺). The latter anion reacts with (NH₄)PF₆ to give the hydride-bridged nitrosyl complex [Mn₂(μ-H)(μ-NO)(CO)₆(μ-dppm)] and with [AuCl(PPh₃)] to give the trinuclear cluster [AuMn₂(μ-NO)(CO)₆(μ-dppm)(PPh₃)] (Mn-Au = ca. 2.68 Å; Mn-Mn = 2.879(2) Å). Both products are derived from the addition of the added electrophile at the intermetallic bond and rearrangement of the nitrosyl ligand into a bridging position. In contrast, methylation of the anion with CF₃SO₃Me takes place at the nitrosyl ligand to yield the unstable methoxylimide derivative [Mn₂(μ-NOMe)(CO)₆(μ-dppm)]. Analogous reactions at the nitrosyl ligand take place upon the addition of HBF₄·OEt₂ to the nitrosyl-bridged hydrides [Mn₂(μ-H)(μ-NO)(CO)_n(μ-dppm)_m] (n = 6, m = 1; n = 4, m = 2) to give the corresponding hydroxylimide derivatives [Mn₂(μ-H)(μ-NOH)(CO)_n(μ-dppm)_m]BF₄, which were also thermally unstable and could not be isolated nor fully characterized.