X-ray diffraction structure of Co2(CO)4(μ-PhC≡CH)[(Z)-Ph2PCH=CHPPh2[: proof for diphosphine ligand chelation

Treatment of the dicobalt compound Co₂(CO)₆(-PhCCH) (1) with the unsaturated diphosphine ligand (Z)-Ph₂PCH=CHPPh₂ gives the chelating diphosphine compound Co₂(CO)₄(-PhCCH)[(Z)-Ph₂PCH=CHPPh₂] (2) when the reaction is carried in refluxing 1,2-dichloroethane or in the presence of Me₃NO. 2 was characterized in solution by IR and ³¹P NMR spectroscopy, and the molecular structure of Co₂(CO)₄(-PhCCH)[(Z)-Ph₂PCH=CHPPh₂] was established by X-ray diffraction analysis, which confirmed the chelation of the P-ligand to a single cobalt center. Co₂(CO)₄(-PhCCH)[(Z)-Ph₂PCH=CHPPh₂] crystallizes in the monoclinic space group P2₁/c, a = 10.151(1), b = 32.694(5), c = 11.051(5) Å, = 111.14(1)°, V = 3420.7(9) ų, Z = 4, and d _calc = 1.414. The two distinct ³¹P resonances found in the ³¹P NMR spectrum of 2 are discussed relative to the X-ray structure and other structurally similar cobalt–alkyne complexes. Thermolysis of Co₂(CO)₄(-PhCCH)[(Z)-Ph₂PCH=CHPPh₂] led only to the slow decomposition of Co₂(CO)₄(-PhCCH)[(Z)-Ph₂PCH=CHPPh₂] and not to the formation of the isomeric bridged-diphosphine complex.     

Site-selective ligand substitution in CoRu(CO)7(μ-PPh2) using (Z)-Ph2PCH=CHPPh2 and reactivity of DMAD with CoRu(CO)5[(Z)-Ph2PCH=CHPPh2](μ-PPh2). X-ray structures of CoRu(CO)5[(Z)-Ph2PCH=CHPPh2](μ-PPh2) and CoRu(CO)3(μ-CO)[(Z)-Ph2PCH=CHPPh2] [μ, η3-Ph2PC(CO2Me)C(CO2Me)]

The heterometallic complex CoRu(CO)₇(μ-PPh₂) (1) reacts with the diphosphine ligand (Z)-Ph₂PCH=CHPPh₂ under both thermolysis and Me₃NO activation to furnish CoRu(CO)₅[(Z)-Ph₂PCH=CHPPh₂](μ-PPh₂) (2) in good yield. Treatment of 2 with dimethyl acetylenedicarboxylate (DMAD) at elevated temperature leads to the formal insertion of the DMAD ligand into the Co–phosphido bond and formation of the metallocyclic compound CoRu(CO)₃(μ-CO)[(Z)-Ph₂PCH=CHPPh₂][μ,η³-Ph₂PC(CO₂Me)C(CO₂Me)] (3) that contains a 5e^? alkenylphosphine moiety. These new CoRu compounds have been isolated by chromatography and fully characterized in solution by IR and NMR (¹H and ³¹P) spectroscopies, and the solid-state structures of both 2 and 3 have been determined by X-ray diffraction analysis. CoRu(CO)₅[(Z)-Ph₂PCH=CHPPh₂](μ-PPh₂) crystallizes in the monoclinic space group P2 ₁/n, a = 11.493(8), b = 20.24(1), c = 17.04(1) Å, β = 91.03(1)°, V = 3964(5) ų, Z = 4, D _calc = 1.477 Mg/m³; R = 0.0475, R _w = 0.1054 for 5120 observed reflections with I > 2σ (I). CoRu(CO)₃(μ-CO)(Z)-Ph₂PCH=CHPPh₂][μ,η³-Ph₂PC(CO₂Me)C(CO₂Me)], as the CH₂Cl₂ solvate, crystallizes in monoclinic space group P2 ₁/c, a = 17.0307(9) Å, b = 11.2124(6) Å, c = 24.083(1) Å, β = 97.755(1)°, V = 4556.8(4) ų, Z = 4, D _calc = 1.579 Mg/m³; R = 0.0379, R _w = 0.0609 for 10774 observed reflections with I > 2σ(I). The regioselective coordination of the (Z)-Ph₂PCH=CHPPh₂ ligand to the two equatorial sites of the ruthenium center in 2 and the presence of the metallocyclic alkenylphosphine ligand in 3 are confirmed by the structural studies. The regiochemistry found in the coordination of (Z)-Ph₂PCH=CHPPh₂ to 1 is contrasted with the related diphosphine ligands bma and bpcd, while the DMAD insertion reactivity with 2 is discussed relative to alkyne reactions reported for the parent compound CoRu(CO)₇(μ-PPh₂).     

X-ray diffraction structure of Re2(CO)8[(Z)-Ph2PCH=CHPPh2]. Proof for diphosphine ligation across the Re–Re bond

Treatment of either Re₂(CO)₈(μ-H)(μ-η ¹,η ²-CH=CHBu) or Re₂(CO)₈(MeCN)₂ with the unsaturated diphosphine ligand (Z)-Ph₂PCH=CHPPh₂ gives the known bridging phosphine compound Re₂(CO)₈[(Z)-Ph₂PCH=CHPPh₂]. The solid-state structure of Re₂(CO)₈[(Z)-Ph₂PCH=CHPPh₂] was established by X-ray diffraction analysis, which confirmed the attachment of the diphosphine ligand to each rhenium center. Re₂(CO)₈[(Z)-Ph₂PCH=CHPPh₂] crystallizes in the tetragonal space group P4 ₂ bc, a = 18.054(2) Å, c = 22.289(4) Å, V = 7265(2) ų, Z = 8, and d _calc = 1.900. The two Re(CO)₄ units that are tethered by the diphosphine ligand exhibit a staggered rotational geometry.     

PhPMe2 ligand substitution in the tetracobalt cluster Co4(CO)10(μ4-PPh)2: X-ray diffraction structure of Co4(CO)8(PPhMe2)2(μ4-PPh)2

The thermal substitution chemistry of the tetracobalt cluster Co₄(CO)₁₀(₄-PPh)₂ with the phosphine ligand PhPMe₂ (2.5 equiv) has been explored and found to afford the bis(phosphine)-substituted cluster Co₄(CO)₈(PPhMe₂)₂(₄-PPh)₂ as the major reaction product. The regiochemistry and stereoselectivity exhibited by the two phosphine ligands in Co₄(CO)₈(PPhMe₂)₂(₄-PPh)₂ have been unambiguously established by X-diffraction analysis as having a 1,3-cis orientation. Co₄(CO)₈(PPhMe₂)₂(₄-PPh)₂ crystallizes in the monoclinic space group P2₁/n,a=10.314(1) Å,b=18.051(3) Å,c=21.313(2) Å, =90.10(1)°,V=3968.0(8) ų,Z=4,d _calc=1.590 g cm^–3;R=0.051,R _w=0.042 for 4987 observed reflections withI>3(I). Generalizations concerning the stereochemical disposition of two P-ligands about the Co₄(CO)₈P₂(₄-PPh)₂ (where P=phosphine or phosphite) polyhedron are discussed with respect to the cone angle of the P-ligand and its steric interactions with the capping phenylphosphinidene group.     

Regiospecific ligand addition to the donor–acceptor compound Ru2(CO)6(bpcd): syntheses and X-ray diffraction structures of Ru2(CO)5L(bpcd) and Ru2(CO)5L[μ-C=C(PPh2)C(O)CH2C}(O)](μ2-PPh2) (where L = PMe3 and tBuNC)

Thermal and Me₃NO-assisted activation of the donor–acceptor complex Ru₂(CO)₆(bpcd) (1) [where bpcd = 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione] with PMe₃ or ^tBuNC affords the mono-substituted complexes Ru₂(CO)₅L(bpcd), as a result of regiospecific ligand attack at the diphosphine-substituted ruthenium center. Solution NMR measurements (¹H and ³¹P) reveal that the PMe₃ derivative exists as a noninterconverting mixture of axial (3a) and equatorial (3e) isomers, with the only the equatorial isomer being observed for Ru₂(CO)₅(^tBuNC)(bpcd) (5). Near-UV irradiation of 1 in the presence of added ligand yields Ru₂(CO)₅L(bpcd), in addition to the known ₂-phosphido complex Ru²(CO)⁶ [-C=C(PPh₂)C(O)CH₂C(O)](₂-PPh₂) (2) and the corresponding phosphido-substituted complexes Ru²(CO)_5L[-{C =C(PPh₂)C(O)CH₂C}(O)]₂-PPh₂)[4 (L = PMe₃); 6 (L = ^tBuNC)]. As with compounds 3a, 3e, and 5, both 4 and 6 exhibit ligand attachment at the diphosphine-substituted ruthenium center. The molecular structures of 3e, 4, 5, and 6 were determined by X-ray crystallography. 3e, as the 1/2 C₆H₆ solvate, crystallizes in the monoclinic space group C2/c: a = 40.573(3) Å, b = 10.2663(9) Å, c = 18.347(1) Å, = 95.371(6)°, V = 7609(1) ų and Z = 8; 4, crystallizes in the monoclinic space group P2₁/n: a = 10.8241(8) Å, b = 18.074(1) Å, c = 19.194(1) Å, = 96.968(6)°, V = 3727.3(5) ų, and Z = 4; 5, as the 1/2CH₂Cl₂ solvate, crystallizes in the monoclinic space group C2/c: a = 40.955(3) Å, b = 9.7230(6) Å, c = 20.542(1) Å, = 106.596(5)°, V = 7839.2(9) ų, and Z = 8; 6, as the 1/2C₅H₁₂ solvate, crystallizes in the monoclinic space group P2₁/c: a = 21.773(2) Å, b = 10.907(3) Å, c = 18.744(4) Å, = 114.68(1)°, V = 4045(1) ų, and Z = 4. The site occupied by the PMe₃ and ^tBuNC ligands in these compounds is discussed relative to the steric size/electronic properties of the ancillary ligand and its interaction with the bpcd ligand.     

Thermolysis of the tetrahedrane cluster PhCCo3(CO)3(μ-CO)Cp2 with the unsaturated diphosphine ligands (Z)-Ph2PCH=CHPPh2 and 4,5-Bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd): Redox properties and molecular structure of PhCCo3(CO)(μ-CO)[(Z)-Ph2PCH=CHPPh2]Cp2

Thermolysis of the tricobalt cluster PhCCo₃(CO)₃(μ-CO)Cp₂ (1) with the diphosphine ligands (Z)-Ph₂PCH=CHPPh₂ and 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) has been examined and found to give the diphosphine-substituted clusters PhCCo₃(CO)[(Z)-Ph₂PCH=CHPPh₂](μ-CO)Cp₂ (2) and PhCCo₃(CO)(bpcd)(μ-CO)Cp₂ (3) in moderate yield. The new compounds 2 and 3 have been isolated and characterized in solution by IR and NMR (¹H and ³¹P) spectroscopies. VT ³¹P NMR data reveal that the chelating diphosphine ligand is fluxional in solution and exhibits a rocking motion between the axial and equatorial sites that renders both phosphorus moieties identical at ambient temperature. The molecular structure of PhCCo₃(CO)[(Z)-Ph₂PCH=CHPPh₂](μ-CO)Cp₂ (2) has been determined by X-ray crystallography. PhCCo₃(CO)[(Z)-Ph₂PCH=CHPPh₂](μ-CO)Cp₂ crystallizes, as the CH₂Cl₂ solvate, in the monoclinic space P2₁/n, a = 16.822(2) Å, b = 10.554(1) Å, c = 23.135(3) Å, β = 100.944(2)^°, V = 4032.4(8) ų, Z = 4, and d _calc = 1.537 Mg/m³; R = 0.0488, R _w = 0.0725 for 9431 reflections with I > 2σ(I). The solid-state structure of cluster 2 establishes the chelating nature of the ancillary (Z)-Ph₂PCH=CHPPh₂ ligand at the unique Co(CO)P₂ center via coordination at an equatorial and an axial site. The redox behavior of clusters 2 and 3 has been explored by cyclic voltammetry and chronocoulometry. Each cluster reveals the presence of two one-electron oxidations of common origin due to the oxidation of a Co–Co bonding orbital. Whereas cluster 2 does not exhibit an accessible reduction process in CH₂Cl₂, a ligand-based one-electron reduction was found for cluster 3 given its low-lying π* LUMO associated with the bpcd ligand. The electrochemical data for clusters 2 and 3 are discussed with respect to the reported redox chemistry for this genre of tricobalt cluster and the bpcd ligand.     

Reaction between [Ru3(CO)10(μ-dppm)] (dppm = Ph2PCH2PPh2) and Te2(C6H4OEt-4)2: X-ray crystal structure of [Ru2(CO)6{μ-C6H4PPh(CH2)PPh}]

Treatment of [Ru₃(CO)₁₀(-dppm)] (1) with the ditelluride Te₂(C₆H₄OEt-4)₂ in refluxing toluene afforded the new aryltellurol bridged complex [Ru₂(CO)₄(-TeC₆H₄OEt-4)₂ (-dppm)] (2) together with three known complexes [Ru₄(CO)₈(-CO)(₄-Te)₂(-dppm)] (3), [Ru₂(CO)₆{-CH₂PPh(C₆H₄)PPh}] (4), and [Ru₂(CO)₆{-C₆H₄PPh(CH₂)PPh}] (5). All the four complexes were characterized by spectroscopic methods, including an X-ray structure determination for 5. Complex 5 crystallizes in the monoclinic space group P2₁/c with a = 13.650(2), b = 9.995(2), c = 18.929(3) Å, = 97.49(2)°, V = 2560.4(8) ų, and Z = 4. In this complex the two ruthenium atoms are bridged by the phosphino-phosphide ligand C₆H₄PPh(CH₂)PPh which is attached to one Ru by the C₆H₄ group and a P atom while to the other Ru by both the two P atoms. Both the ruthenium atoms show distorted octahedral geometry. The Ru—Ru bond length is 2.8719(7) Å.     

Bridging and chelating diphosphine ligands in Ru3(μ-H)(μ-N=CPh2)(CO)8(P—P). X-ray diffraction structures of Ru3(μ-H)(μ-N=CPh2)(CO)8(dmpe) and Ru3(μ-H)(μ-N=CPh2)(CO)8(bpcd)

Treatment of the azavinylidene-bridged cluster Ru₃(-H)(-N=CPh₂)(CO)₁₀ (1) with the diphosphine ligand bis(dimethylphosphino)ethane (dmpe) gives Ru₃( -H)(-N=CPh₂)(CO)₈(dmpe) (2) in moderate yield, while the ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) reacts with Ru₃( -H)(-N=CPh₂)(CO)₁₀ in the presence of Me₃NO to furnish Ru₃( -H)(-N=CPh₂)(CO)₈(bpcd) (3) in low yield. Each new cluster has been isolated and characterized in solution by IR and NMR (¹H and ³¹P) spectroscopies, and the coordination mode exhibited by the ancillary diphosphine ligand in 2 and 3 has been established by X-ray crystallography. Ru₃( -H)(-N=CPh₂)(CO)₈(dmpe) crystallizes in the monoclinic space group P2(1)/c, a = 10.791(1) Å, b = 16.377(1) Å, c = 18.148(1) Å, = 96.675(2)°, V = 3185.3(4) ų, Z = 4, D _cacl = 1.791 Mg/m³; R = 0.0360, R _w = 0.0866 for 7522 observed reflections with I > 2(I). Ru₃(-H)(-N=CPh₂)(CO)₈(bpcd) crystallizes, as the CH₂Cl₂ solvate, in the triclinic space group , a = 11.956(1) Å, b = 14.228(1) Å, c = 31.409(3) Å, = 89.377(2)°, = 79.344(2)°, = 77.235(2)°, V = 5118.4(8) ų, Z = 2, D _calc = 1.670 Mg/m³; R = 0.0557, R _w = 0.1069 for 10977 observed reflections with I > 2(I). The structural details of clusters 2 and 3 are contrasted with Ru₃(-H)(-N=CPh₂)(CO)₇(-dppm)(-dppm), which is the only known structurally characterized phosphine-substituted cluster of this genre.     

Reaction of the dicobalt alkyne compound Co2(CO)6(μ-dmad) with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd). Spectroscopic properties, X-ray diffraction data, and thermal reactivity of the chelating isomer of Co2(CO)4(bpcd)(μ-dmad)

Treatment of Co₂(CO)₆(-dmad) (where dmad = dimethyl acetylenedicarboxylate) with the bidentate ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) in the presence of added Me₃NO affords the new alkyne compound Co₂(CO)₄(bpcd)(-dmad) in good yield. Both IR and ³¹P NMR spectroscopies indicate that the bpcd ligand is coordinated to a single cobalt center in a chelating fashion in solution. The solid-state structure of Co₂(CO)₄(bpcd)(-dmad) is identical to the solution structure Co₂(CO)₄(bpcd)(-dmad), as determined by X-ray diffraction analysis. Co₂(CO)₄(bpcd)(-dmad) crystallizes in the triclinic space group P-1, a = 10.7460(8) Å, b = 11.628(2) Å, c = 15.077(1) Å, = 95.831(9)°, = 91.205(7)°, = 101.526(9)°, V = 1834.7(3) ų, Z = 2, and d _calc = 1.514 g/cm³; R = 0.0489, R _w = 0.0528 for 2854 reflections with I > 3(I). The thermal reactivity of Co₂(CO)₄(bpcd)(-dmad) has been briefly explored by spectroscopic methods, and evidence is presented for the attack of one of the PPh₂ groups on an alkyne carbon atom in Co₂(CO)₄(bpcd)(-dmad) to from the zwitterionic hydrocarbyl compound Co₂(CO)₄(-²:²:¹:¹-(MeO₂C)=C(CO₂Me)PPh₂C=C(PPh₂)C(O)CH₂C(O)] upon thermolysis. The redox chemistry of both Co₂(CO)₄(bpcd)(-dmad) and Co₂(CO)₄[-²:²:¹:¹-(MeO₂C) C=C(CO₂Me)PPh₂C=C(PPh₂)C(O)CH₂C(O)] has been explored by cyclic voltammetery.     

Chelation of a diphosphine ligand at FeCo2(CO)9(μ3-S): Spectroscopic and X-ray diffraction data for FeCo2(CO)7(bpcd)(μ3-S)

The tetrahedrane cluster, FeCo₂(CO)₉(₃-S), reacts with the redox-active ligand, 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd), to give the disubstituted cluster, FeCo₂(CO)₇(bpcd)(₃-S), as the sole product. This diphosphine-substituted cluster contains a cobalt-bound, chelating bpcd ligand. Both IR and ³¹P NMR spectroscopies have been employed in the solution characterization of FeCo₂(CO)₇(bpcd)(₃-S), and the solid-state structure has been unequivocally established by X-ray diffraction analysis. FeCo₂(CO)₇(bpcd)(₃-S) crystallizes in the monoclinic space group C2/c, a = 34.494(3) Å, b = 11.4194(9) Å, c = 18.634(2) Å, = 98.103(7)°, V = 7266.7(9) ų, Z = 8, and d_calc = 1.584 g/cm³. Cyclic voltammetric studies on FeCo₂(CO)₇(bpcd)(₃-S) reveal the presence of two quasireversible redox responses assigned to the 0/1^– and 1^–/2^– redox couples. The orbital composition of these redox couples has been examined by carrying out extended Hückel MO calculations on the model complex FeCo₂(CO)₇(H₄-bpcd)(₃-S), with the results being compared to related cluster compounds.     

Alkyne insertion and coupling reactions of methyl propiolate with the heterometallic dimers CoRu(CO)7(μ-PPh2) and CoRu(CO)5[(Z)-Ph2PCH = CHPPh2](μ-PPh2): X-ray diffraction structures of CoRu(CO)4(μ-CO)[μ-PPh2C(O)CH(CCO2Me)C(O)CHC (CO2Me)] and CoRu(CO)3(μ-CO)[(Z)-Ph2PCH = CHPPh2][μ-PPh2C(O)C(CO2Me)CH]

The reaction of the terminal alkyne methyl propiolate with the heterometallic dimers CoRu(CO)₇(μ-PPh₂) (1) and CoRu(CO)₅[(Z)-Ph₂PCH=CHPPh₂](μ-PPh₂) (2) has been investigated at 65^°C in toluene. In the reaction of 1, chromatographic purification afforded a minor band, from which the two species RuCo(CO)₄(μ-CO)[μ-PPh₂C(O)CHC(CO₂Me)] and RuCo(CO)₄(μ-CO)[μ-PPh₂CHC(CO₂Me)] were observed by ¹H NMR spectroscopy, and one major band, whose ¹H NMR spectrum revealed the presence of multiple species. The identity of one of the compounds in the major component has been established as that of CoRu(CO)₄(μ-CO)[μ-PPh₂C(O)CH(CCO₂Me)C(O)CHC(CO₂Me)] (3) by X-ray diffraction analysis. The solid-state structure of 3 confirms the double insertion of CO and head-to-head coupling of the methyl propiolate that accompanies the formation of this product. Compound 3 crystallizes in the triclinic space group P-1, a = 8.4035(4), b = 9.6721(5), c = 17.678(1) Å, α = 94.135(2), β = 103.318(2), γ = 101.336(2)^°, V = 1360.5(1) ų, Z = 2, D _calc = 1.732 Mg/m³; R = 0.0300, R _w = 0.0760 for 8630 reflections with I > 2σ(I). The ruthenium-bound diphosphine ligand in 2 exerts a controlling influence on the reaction with added alkyne insomuch as only the mono-insertion product CoRu(CO)₃(μ-CO)[(Z)-Ph₂PCH=CHPPh₂][μ-PPh₂C(O)C(CO₂Me)CH] (4) is formed as a single regioisomer. The molecular structure of 4 was established by X-ray diffraction analysis and 4 was found to crystallize in the monoclinic space group P2₁/c, a = 19.483(7), b = 11.905(4), c = 20.131(7) Å, β = 110.455(6)^°, V = 4375(3) ų, Z = 4, D _calc = 1.466 Mg/m³; R = 0.0961, R _w = 0.1683 for 6262 reflections with I > 2σ(I). The reactivity of methyl propiolate with 1 and 2 is compared with the known reactivity that has been reported for other alkynes.     

CO replacement in Ru3(CO)12 by 2,3-bis(diphenylphosphino)maleic anhydride (bma). X-ray structures of Ru3(CO)10(bma)·H2O and

Thermolysis of Ru₃(CO)₁₂ with 2,3-bis(diphenylphosphino)maleic anhydride (bma) in toluene solution gives the new compounds Ru₃(CO)₁₀(bma) (2), Ru₂(CO)₆(bma) (3), and (4). All compounds have been isolated and characterized in solution by IR and³¹P NMR spectroscopy. The solid-state structures of2, as the monohydrate, and4 were established by X-ray crystallography. Ru₃(CO)₁₀(bma)·H₂O crystallizes in the monoclinic space groupC2/c,a=12.741(2) Å,b=19.548(2) Å,c=32.973(4) Å, β=96.847(9)°,V=8154(2) ų,Z=8,d _calc=1.740 g cm^?3;R=0.046,R _w =0.051 for 2541 observed reflections withl>3σ(l). The bma ligand in2 is bound to the triruthenium frame in a bridging fashion, with equatorially disposed PPh₂ groups. The X-ray structure of2 reveals an extreme twisting of the maleic anhydride ring away from the plane defined by the plane of the three ruthenium atoms, along with a significant lengthening of the maleic anhydride C=C π bond. crystallizes in the monoclinic space groupP2₁/c,a=9.3113(5) Å,b=18.164(1) Å,c=20.097(1) Å, β-102.021(4)°,V=3324.5(3) ų,Z=4,d _calc=1.671 g cm^?3;R=0.024,R _w =0.030 for 3499 observed reflections withl>3σ(l). The presence of the μ₂ moiety and P?C (maleic anhydride) bond cleavage attendant in the formation of4 are confirmed by X-ray analysis. The relationship of the compounds3 and4 to the dimeric compounds Ru₂(CO)₆(bpcd) and [where bpcd=4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione] is discussed. Independent studies dealing with Ru₃(CO)₁₀(bma) (bridging isomer) have shown that cluster2 is stable in toluene solution at elevated temperature and does not afford compounds3 and4, suggesting the intermediacy of the putative chelating isomer of Ru₃(CO)₁₀(bma) (1) as the source of3 and4.     

Regiospecific CO substitution in (μ-H)Ru3(μ3− η3-CHCHCMe)(CO)9 by 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione(bpcd). X-ray structure of (μ-H)Ru3(μ3−η3-CHCHCMe)(CO)7(bpcd)⋅MeOH

The triruthenium cluster ( -H)Ru₃( ₃–³-CHCHCMe)(CO)₉ reacts with the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) in the presence of Me₃NO to afford ( -H)Ru₃( ₃– ³-CHCHCMe)(CO)₇(bpcd) in moderate yield. This new cluster has been isolated and characterized in solution by IR and NMR (¹H, ³¹P) spectroscopies, and the solid-state structure has been established by X-ray crystallography. ( -H)Ru₃( ₃– ³-CHCHCMe)(CO)₇(bpcd) MeOH crystallizes in the triclinic space group P , a = 11.2426(8) Å, b = 11.7141(8) Å, c = 16.195(1) Å, = 102.041(5)°, = 95.128(5)°, = 102.553(6)°, V = 2008.4(3) ų, Z = 2, d _calc. = 1.733 g/cm³; R = 0.0488, R _w = 0.0546 for 2212 observed reflections with I > 3 (I). The X-ray structure reveals that the bpcd ligand is bound exclusively to the Ru₃ core at the ruthenium center coordinated by the terminal CH unit of the -allylic ₃– ³-CHCHCMe moiety.     

X-ray diffraction structure of the phosphido-bridged mixed-metal cluster Fe2(CO)6(μ3-PPh)2Pt(dppe)

Treatment of Fe₂(CO)₆(₂-PPhH)₂ with BuLi (2 equiv.), followed by the addition of PtCl₂ (dppe), affords the phosphido-bridged cluster Fe₂(CO)₆(₃-PPh)₂Pt(dppe). The Fe₂Pt cluster was isolated and characterized in solution by IR and ³¹P NMR spectroscopy, and the molecular structure of Fe₂(CO)₆(₃-PPh)₂Pt(dppe) determined by X-ray diffraction analysis. Fe₂(CO)₆(₃-PPh)₂Pt(dppe) crystallizes in the orthorhombic space group P_bca, a = 17.539(3) Å, b = 21.490(2) Å, c = 22.959(3) Å, V = 8653.5(18) ų, Z = 8, d_calc = 1.670 g cm^–3; R = 0.0644, R_w = 0.0389 for 5040 observed reflections with I > 3(I).     

X-ray crystal structure ofcis-H(Ph3Si)Pt[Ph2P(CH2)4PPh2] ·0.5 C6H6

The title compound, cis-hydrido(triphenylsilyl)-1,4-butanediyl-bis-(diphenylphosphine)platinum(II) (I), crystallizes in the monoclinic space groupP2 ₁/n (No. 14) witha=9.472(4),b=16.924(5),c=25.799(4) Å, β=91.29(3)° andZ=4. The structure was solved using the direct methods and refined by the full-matrix least-squares procedure to yield residuals ofR=0.024 andR _w =0.025 based on 4160 unique reflections. The square-planar geometry about the Pt atom is angularly distorted with P(1)?Pt?P(2) and Si?Pt?P(2) angles of 103.5(1) and 102.1(1)°, respectively. The Pt?P(1) bond is longer than the Pt?P(2) bond due to thetrans influence of the SiPh₃ group. Distortion due to steric bulk of the ligands is accommodated by the opening of the tetrahedral angles at the silicon and phosphorous atoms.     

Synthesis, characterization, and single crystal X-ray diffraction studies of cis-Ph2C2H2(η5-C5H4)2Ca(THF)2

cis-[(1,2-diphenyl-1,2-dicyclopentadienyl)ethanediyl]bis(tetrahydrofuran)calcium is prepared by reductively coupling phenylfulvene with activated calcium to produce cis and trans isomers which can be separately crystallized. The cis isomer crystallizes in the monoclinic space group P2₁/c. The cell parameters are: a = 9.7006(1), b = 18.9839(1), c = 14.2018(2) Å, = 91.263(1)°, V = 2614.70(5) ų, D _calc = 1.252 mg/m³, and Z = 4. Spectroscopic and crystallographic data for the cis-isomer are presented and discussed.     

X-ray diffraction studies oncis-[Ru(bpy)2(PMe3)Cl+][ClO4 −] andcis-[Ru(bpy)2{PMe2(o-tol)}Cl+][ClO4 −]; two ordered structures in thecis-bis(bipyridyl)chloro(phosphine)-ruthenium(II) series

The complexcis-[Ru(bpy)₂(PMe₃)Cl⁺][ClO₄ ^?] crystallizes in space group P2₁/c andcis-[Ru(bpy)₂{PMe₂(o-tol)]Cl⁺][ClO₄ ^?] crystallizes in space group $P\bar 1$ ; each is present as a racemate and neither structure suffers from disorder. The Ru?PMe₂(o-tol) bond length of 2.324(2)Å is slightly longer than the simple Ru?PMe₃ bond length of 2.310(2) Å.     

Carbon–hydrogen and carbon–phosphorus bond cleavage in a triruthenium cluster complex containing dppm: The crystal and molecular structures of Ru3(CO)6{μ 3-OPPh2 C2H(C6H4)PPhCH2PPh}(μ 3-OPPh2)Ph and Ru3(CO)6 {μ-OPPh2C2H(C6H4)PPhO}(μ-PPh2)(μ-PPh2O)

The crystal and molecular structures of Ru₃(CO)₆{μ ₃-OPPh₂C₂H(C₆H₄)PPhCH₂PPh}-(μ ₃-OPPh₂)Ph (1) and Ru₃(CO)₆{μ-OPPh₂C₂H(C₆H₄)PPhO}(μ-PPh₂)(μ-PPh₂O) (2) have been determined by single crystal X-ray diffraction. Both complexes contain oxygen atoms oxidatively inserted into phosphorus–ruthenium bonds, and unique σ/π multidentate ligands formed from C $---{\text{H}}$ H and C $--$ P bond cleavage in bis(diphenylphosphino)acetylene and bis(diphenylphosphino)methane. Complex 1 crystallized in the triclinic space group ${\bar 1}$ , with lattice parameters a = 11.642(4) Å, b = 15.018(5) Å, c =16.587(5) Å, α = 2.48(3)°, β = 76.47(2)°, γ = 70.35(3)°, V = 2651.1(15) ų, Z = 2. Complex 2 crystallized in the centered monoclinic space group, C2/c, with lattice parameters a = 34.467(4) Å, b = 14.274(2) Å, c = 23.258(3) Å, β = 5.29(1)°, V = 11394(3) ų, Z = 8.     

2-pyridylbis(diphenylphosphino)methane chemistry. Synthesis and structures of [Cu(μ−η2:η1(Ph2P)2−CHC5H4N)(THF)]2(BF4)2 and [Ni(Ph2PCH2C5H4N)2]-[NiCl4]·0.85CH2Cl2and [Ni(Ph2PCH2C5H4N)2]-[NiCl4]·0.85CH2Cl2

Reaction of 2-pyridylbis(diphenylphosphino)methane (NPP) with [Cu(NCMe)₄]BF₄ and with [Ni(H₂O)₆]Cl₂ forms [Cu(NPP)(THF)]₂(BF₄)₂ (after recrystallization in the presence of THF) (1) and NiCl₂(NPP) (2) respectively Attempts to recrystallize2 led ultimately to the ligand cleavage product [Ni(Ph₂PCH₂C₅H₄N)₂][NiCl₄]·0.85CH₂Cl₂ (3). Complex1 crystallizes in the monoclinic space groupP2₁/n witha=13.148(2),b=19.221(2),c=13.458(2) ų, β=108.61(1)^o,V=3222.6(8) ÅZ=2. The structure was refined onF ² toR1=0.11,wR2=0.14 (R1=0.044 forI≥2σ(I)) for 5661 observed reflections. Complex3 crystallizes in the triclinic space groupP1 witha=12.795(2),b=17.535(1),c=10.203(1) Å, α=107.564(6), β=114.260(8), γ=78.435(8)^o,V=1982.1(8) ų;Z=2. The structure was refined onF toR1=0.044,R _w=0.059 for 3534 observed reflections. Dinuclear complex1 has crystallographically imposed centrosymmetry with the NPP ligands arranged in a head-to-tail fashion. The Cu...Cu separation of 3.372(1) Å is too long to support significant metal-metal interaction. Complex3 results from the cleavage of a {PPh₂} unit from the NPP ligand and contains an approximately square nickel atom surrounded by two Ph₂PCH₂C₅H₄N ligands coordinated in a head-to-head fashion.     

Reaction of bis(dimethoxyphosphino)dimethylhydrazine (dmpdmh) with Ru3(CO)12: Evidence for facile ligand fragmentation in Ru3(CO)10(dmpdmh) to give Ru4(CO)12[μ-N(Me)N(Me)], Ru3(CO)11[P(OMe)3], and Ru3(CO)9[μ-P(OMe)3]

Thermolysis of the cluster Ru₃(CO)₁₂ with the bis(phosphanyl)hydrazine ligand (MeO)₂PN (Me)N(Me)P(OMe)₂ (dmpdmh) in toluene at 75°C furnishes the known clusters Ru₄(CO)₁₂ [-N(Me)N(Me)] (2) and Ru₃(CO)₁₁[P(OMe)₃] (3), in addition to the new cluster Ru₃ (CO)₁₀(dmpdmh) (1) and the phosphite-tethered cluster Ru₃(CO)₉[-P(OMe)₃] (4). The simple substitution product Ru₃(CO)₁₀(dmpdmh), a logical intermediate to clusters 2–4, was synthesized by treating Ru₃(CO)₁₂ with Me₃NO in CH₂Cl₂ at room temperature, and independent thermolysis reactions using cluster 1 was shown to yield clusters 2–4. The solid-state structure of clusters 2 and 4 were unequivocally established by X-ray diffraction analysis. Ru₄(CO)₁₂[-N(Me)N(Me)] crystallizes in the orthorhombic space group Pnna (#52), a = 12.913(1), b = 13.3238(6), c = 12.5690(8) Å, V = 2162.5(2) ų, Z = 4, and d _calc = 2.452 g/cm³. Ru₃(CO)₉[-P(OMe)₃] crystallizes in the triclinic space group P a = 9.586(1), b = 14.354(1), c = 14.997(2) Å, = 89.82(1)°, = 98.36(1)°, = 92.010(8)°, V = 2040.4(4) ų, Z = 4, and d _calc = 2.212 g/cm³. The coordination of the dimethylazo linkage to the four ruthenium atoms in 2 and the phosphorus atom and one of the oxygen atoms of the methoxy groups to the three ruthenium centers in 4 are confirmed by X-ray analysis.