Abstract A rhodamine-based chemosensor was synthesized and found to selectively bind ferric ions over other metal ions (Na+, K+, Ca2+, Mg2+, Fe2+, Zn2+, Cd2+, Co2+, Hg2+ Cr3+, Al3+) in an organic-aqueous mixture (CH3CN-MES). Upon addition of ferric ions, the spirolactam ring opens, producing a visual color change and a fluorescence intensity increase, i.e. a “turn on” optical response at 577 nm is observed. The chemosensor coordinates to ferric ions in 1:1 stoichiometry with a calculated K a = 3.5 × 104 mol⋅dm−3 by fluorescence spectroscopy and a LoD of 27 ppb. The chemosensor was reversible upon addition of the Fe3+ chelator desferrioxamine. One- and two-dimensional NMR experiments with Al3+ ions aided in understanding of the coordination environment of the ferric ion with the chemosensor, which were confirmed by molecular modeling calculations. X-ray quality crystals of the chemosensor were obtained, and the solid-state structure is reported. Confocal microscopy was used to detect free ferric ions in Staphylococcus aureus. Graphical Abstract

The diphosphine ligand 1,2-bis(diphenylphosphino)benzene (dppbz) reacts with the activated cluster 1,2-Os-3(CO)(10)(MeCN)(2) (1) at room temperature to furnish a mixture of the triosmium clusters 1,2-Os-3(CO)(10)(dppbz) (2) and 1,1-Os-3(CO)(10)(dppbz) (3), along with a trace amount of the hydride cluster HOs3(CO)(9)[mu-1,2-PhP(C6H4-eta(1))C6H4PPh2] (4). The dppbz-bridged cluster 2 forms as the kinetically controlled product and irreversibly transforms to the corresponding chelated isomer 3 at ambient temperature. The disposition of the dppbz ligand in 2 and 3 has been established by X-ray crystallography and P-31 NMR spectroscopy, and the kinetics for the conversion 2 -> 3 have been followed by UV-vis spectroscopy in toluene over the temperature range 318-343 K. The calculated activation parameters (Delta H-double dagger = 21.6(3) kcal/mol; Delta S-double dagger = 11(1) eu) and lack of CO inhibition support an intramolecular isomerization mechanism that involves the simultaneous migration of phosphine and CO groups about the cluster polyhedron. The reaction between 1 and the fluorinated diphosphine ligand 1,2-bis(diphenylphosphino)tetrafluorobenzene (dppbzF(4)) was examined under similar reaction conditions and was found to afford the chelated cluster 1,1-Os-3(CO)(10)(dppbzF(4)) (6) as the sole observable product. The absence of the expected bridged isomer 1,2-Os-3(CO)(10)(dppbzF(4)) (5) suggests that the dppbzF4 ligand destabilizes 5, thus accounting for the rapid isomerization of 5 to 6. Near-UV irradiation of clusters 3 and 6 leads to CO loss and ortho metalation of an ancillary aryl group. The resulting hydride clusters 4 and HOs3(CO)(9)[mu-1,2-PhP(C6H4-eta(1))C6F4PPh2] (7) have been isolated and fully characterized by spectroscopic and X-ray diffraction analyses. Both 4 and 7 react with added CO under mild conditions to regenerate 3 and 6, respectively, in quantitative yield. The rearrangements of bridged to chelated diphosphine complexes in this genre of decacarbonyl clusters have been investigated by DFT calculations. The computational results support a concerted process, involving the scrambling of equatorial CO and phosphine groups via a classical merry-go-round exchange scheme. The barriers computed for this mechanism agree well with those that have been measured, and steric compression within the bridged diphosphine groups of the reactants has been calculated to reduce the barrier heights for the rearrangement.

The diphosphine ligand 1,2-bis(diphenylphosphino)benzene (dppbz) reacts with the activated cluster 1,2-Os{sub 3}(CO){sub 10}(MeCN){sub 2} (1) at room temperature to furnish a mixture of the triosmium clusters 1,2-Os{sub 3}(CO){sub 10}(dppbz) (2) and 1,1-Os{sub 3}(CO){sub 10}(dppbz) (3), along with a trace amount of the hydride cluster HOs{sub 3}(CO){sub 9}[{mu}-1,2-PhP(C{sub 6}H{sub 4}-{eta}{sup 1})C{sub 6}H{sub 4}PPh{sub 2}] (4). The dppbz-bridged cluster 2 forms as the kinetically controlled product and irreversibly transforms to the corresponding chelated isomer 3 at ambient temperature. The disposition of the dppbz ligand in 2 and 3 has been established by X-ray crystallography and {sup 31}P NMR spectroscopy, and the kinetics for the conversion 2 {yields} 3 have been followed by UV-vis spectroscopy in toluene over the temperature range 318-343 K. The calculated activation parameters ({Delta}H{sub {+-}} = 21.6(3) kcal/mol; {Delta}S{sub {+-}} = -11(1) eu) and lack of CO inhibition support an intramolecular isomerization mechanism that involves the simultaneous migration of phosphine and CO groups about the cluster polyhedron. The reaction between 1 and the fluorinated diphosphine ligand 1,2-bis(diphenylphosphino)tetrafluorobenzene (dppbzF{sub 4}) was examined under similar reaction conditions and was found to afford the chelated cluster 1,1-Os{sub 3}(CO){sub 10}(dppbzF{sub 4}) (6) as the sole observable product. The absence of the expected bridged more » isomer 1,2-Os{sub 3}(CO){sub 10}(dppbzF{sub 4}) (5) suggests that the dppbzF{sub 4} ligand destabilizes 5, thus accounting for the rapid isomerization of 5 to 6. Near-UV irradiation of clusters 3 and 6 leads to CO loss and ortho metalation of an ancillary aryl group. The resulting hydride clusters 4 and HOs{sub 3}(CO){sub 9}[{mu}-1,2-PhP(C{sub 6}H{sub 4}-{eta}{sup 1})C{sub 6}F{sub 4}PPh{sub 2}] (7) have been isolated and fully characterized by spectroscopic and X-ray diffraction analyses. Both 4 and 7 react with added CO under mild conditions to regenerate 3 and 6, respectively, in quantitative yield. The rearrangements of bridged to chelated diphosphine complexes in this genre of decacarbonyl clusters have been investigated by DFT calculations. The computational results support a concerted process, involving the scrambling of equatorial CO and phosphine groups via a classical merry-go-round exchange scheme. The barriers computed for this mechanism agree well with those that have been measured, and steric compression within the bridged diphosphine groups of the reactants has been calculated to reduce the barrier heights for the rearrangement. « less

The question of post-mortem interval (PMI) or time since death is often the most sought after piece of information associated with a medical death investigation. Based on the observation that DNA degradation disproportionately affects the analysis of larger genetic loci, it was proposed that DNA degradation, as a result of autolysis or putrefaction, could prove suitable as a potential rate-of-change indicator of PMI. Nine randomly amplified polymorphic DNA (RAPD) analysis primers and three sets of directed amplification primers were evaluated to determine their suitability for use in assessing the degree of DNA fragmentation in tissue samples. They were assessed for amplicon specificity, total DNA target sensitivity, allele monomorphism and the observance of degradation-based profile changes. Markers meeting the requisite criteria were then used to assess a range samples degraded under controlled and uncontrolled conditions. Tissue samples collected from seven domestic pigs (Sus scrofa) were incubated under controlled laboratory or uncontrolled field conditions to produce samples simulating those potentially collected in a forensic case. DNA samples isolated from these specimens were then analyzed at those loci which had been determined to meet the requisite criteria. Collectively, data generated from these analyses indicate that genetic profiles generated by this approach can provide information useful for estimating the post-mortem interval, with the locus and amplicons used being most useful during the first 72 hours after death.

The reaction of H2Re2(CO)(8) (1) with Cp*Rh(CO)(2) (2) in refluxing hexane affords tile rnixed-metal clusters H(2)RhRc(2)Cp*(CO)(9) (4, major product), HRh2ReCp*(2)(CO)(6) (5), and HRhRe3CP*(CO)(14) (6). 4 and 5 are electron-precise 48e clusters and display triangular metallic cores, while 6 contains 64 valence electronsand exhibits it spiked-triangular core having it pendant Re(CO)(5) moiety. Heating 1 with CP*Rh-2(2)(CO)(2) (3) gives 4 and 5 its the principal products, in addition to H2Rh2Re2CP*(2)(CO)(8) (7) in low yield. Cluster 7 possesses 60e and contains a tetrametallic core with two face-capping CO and hydride groups. Heating 4 Under CO leads to Cluster fragmentation and formation of Re-2(CO)(10) and 2 in essentially quantitative yield, its assessed by IR spectroscopy. The kinetics for the fragmentation of 4 in toluene under CO have been investigated over the temperature range 325-349 K. by UV- vis spectroscopy. On the basis of the first-order rate constants and tile Eyring activation parameters (Delta H-double dagger = 25.0(8) kcal/mol; Delta(double dagger S) = -2.6(3) eu), it rate-limiting step involving a polyhedral opening of 4 is supported. 4 is thermally and photochernically sensitive, and reactions conducted in the presence of chlorinated solvents furnish the face-shared bioctahedral compound Cp*Rh(mu-Cl)(3)Re(CO)(3) (8). Heating 4 and H2S in benzene at ca. 60 degrees C furnishes the 48c triangular cluster S,Rh3CP*(CO)(4) (9), which contains two Rh(CO)(2) moieties and two face-capping sulfide groups. The reaction of 4 with p-methylbcnzenetliiol gives the sulfido-bridged dimer Cp*Rh(mu-SC6H4Me-P)(3) Re(CO)(3) (11). The dinuclear compounds Cp*Rh(mu-Cl)(mu-SC6H4Me-p))(2)Re(CO)(3) (10)and 11 are formed when 8 is allowed to react with p-methylbenzenethiol. Treatment of 8 and 10 with excess p-methylbenzenethiol yields 11 at elevated temperature in toluene. Compounds 4-11 have been isolated and fully characterized by I R and NM R spectroscopy and by X-ray crystallography. The reactivity displayed by 4 is contrasted with that of tile known indenyl-substituted cluster H2Re2Ir(eta(5)-ind)(CO)(9) prepared earlier by Shapley and co-workers.

The reaction of phosphine ligand endo,endo-2,3-bis(diphenylphosphinomethyl)-5-norbornene (dpmn) with PtCl2(cod) and PtMe2(cod) yields PtCl2(dpmn) (2) and PtMe2(dpmn) (4), respectively. Treatment of 2 with excess MeLi or MeMgCl also furnishes 4 in good yield. Both new platinum compounds have been isolated and characterized by NMR spectroscopy (1H and 31P), elemental analyses, and X-ray crystallography. 2 Crystallizes, as the CH2Cl2 solvate, in the orthorhombic space group Pnma, a = 18.062(3) Å, b = 16.602(3) Å, c = 11.088(2) Å, V = 3,324.7(9) Å3, Z = 4, D cacl = 1.681 mg/m3; R = 0.0432, R w = 0.0759 for 3,755 observed reflections with I > 2σ(I). 4 Crystallizes, as the CH2Cl2 solvate, in the orthorhombic space group Pnma, a = 17.969(3) Å, b = 16.689(3) Å, c = 11.237(2) Å, V = 3,370(1) Å3, Z = 4, D cacl = 1.610 mg/m3; R = 0.0268, R w = 0.0665 for 4,098 observed reflections with I > 2σ(I). The solid-state structures of 2 and 4 confirm the coordination of the platinum(II) center by the seven-membered chelating dpmn ligand; 2 and 4 represent the first structurally characterized examples of organometallic compounds based on the endo,endo-2,3-bis(diphenylphosphinomethyl)-5-norbornene ligand.

The reaction between the ethylidyne-substituted cluster MeCCo2MoCp(CO)8 (1) and the diphosphine ligand 2,3-bis(diphenylphosphino)maleic anhydride (bma) in refluxing CH2Cl2 has been investigated and found to afford the new mixed-metal clusters MeCCo2MoCp(CO)6[trans-2,3-bis(diphenylphosphino)succinic anhydride] (2) and Co2MoCp(CO)5[μ-C(Me)C=C(PPh2)C(O)OC(O)](μ-PPh2) (3), with the latter cluster representing the principal reaction product. Refluxing 1 with bma in either 1,2-dichloroethane or toluene yields only 3. The tetrahedrane cluster PhCCo2Mo(η5-C5H4CHO)(CO)8 (4), which contains a formyl-substituted cyclopentadienyl ring, has also been examined with added bma in refluxing CH2Cl2 and found to give only Co2Mo(η5-C5H4CHO)(CO)5[μ-C(Ph)C=C(PPh2)C(O)OC(O)](μ-PPh2) (5). All three products have been isolated and characterized spectroscopically in solution, and each molecular structure has been determined by X-ray crystallography. Cluster 2 contains a bridging diphosphine ligand with a succinic anhydride ring that results from the formal reduction of the maleic anhydride platform of the bma ligand, while clusters 3 and 5 each exhibit triangular Co2Mo cores, whose one face is capped by a 6e- C(R)C=C(PPh2)C(O)OC(O) [where R = Me (3), Ph (5)] ligand. The observed substitution products are discussed as a function of the capping carbyne group, ancillary polyene ligand, and related derivatives prepared by our groups.

The reaction between the ethylidyne-substituted cluster MeCCo2MoCp(CO)(8) (1) and the diphosphine ligand 2,3-bis(diphenylphosphino)maleic anhydride (bma) in refluxing CH2Cl2 has been investigated and found to afford the new mixed-metal clusters MeCCo2MoCp(CO)(6)[trans-2,3-bis(diphenylphosphino)succinic anhydride] (2) and Co2MoCp(CO)(5)[mu-C(Me)C=C(PPh2)C(O)OC(O)](mu-PPh2) (3), with the latter cluster representing the principal reaction product. Refluxing 1 with bma in either 1,2-dichloroethane or toluene yields only 3. The tetrahedrane cluster PhCCo2Mo(eta(5)-C5H4CHO)(CO)(8) (4), which contains a formyl-substituted cyclopentadienyl ring, has also been examined with added bma in refluxing CH2Cl2 and found to give only Co2Mo(eta(5)-C5H4CHO)(CO)(5)[mu-C(Ph)C=C(PPh2)C(O)OC(O)](mu-PPh2) (5). All three products have been isolated and characterized spectroscopically in solution, and each molecular structure has been determined by X-ray crystallography. Cluster 2 contains a bridging diphosphine ligand with a succinic anhydride ring that results from the formal reduction of the maleic anhydride platform of the bma ligand, while clusters 3 and 5 each exhibit triangular Co2Mo cores, whose one face is capped by a 6e- C(R)C=C(PPh2)C(O)OC(O) [where R = Me (3), Ph (5)] ligand. The observed substitution products are discussed as a function of the capping carbyne group, ancillary polyene ligand, and related derivatives prepared by our groups.

The ligand substitution chemistry of the hexaruthenium cluster Ru(6)(mu(6)-C)(CO)(17) () with several unsaturated diphosphine ligands has been investigated. Thermolysis of with (Z)-Ph(2)PCH[double bond, length as m-dash]CHPPh(2) (dppen) furnishes the new cluster compounds Ru(5)(mu(5)-C)(CO)(12)(mu(3)-dppen) (), Ru(6)(mu(6)-C)(CO)(14)(mu(3)-dppen) (), and Ru(6)(mu(6)-C)(CO)(12)(mu(3)-dppen)(mu-dppen) (). Clusters and are also obtained when a mixture of and dppen is treated with the oxidative-decarbonylation reagent Me(3)NO. Thermolysis or Me(3)NO activation of in the presence of 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) yields Ru(6)(mu(6)-C)(CO)(14)(mu(3)-bpcd) () as the sole observable product. Near-UV irradiation of leads to P-C bond cleavage and the formation of phosphido-bridged cluster Ru(6)(mu(6)-C)(CO)(13)[mu(3)-C[double bond, length as m-dash]C(PPh(2))C(O)CH(2)C(O)](mu-PPh(2)) () in essentially quantitative yield. The reaction between and the ligand 3,4-bis(diphenylphosphino)-5-methoxy-2(5H)-furanone (bmf) leads to the formation of Ru(6)(mu(6)-C)(CO)(14)(mu(3)-bmf) (), which exists as a single diastereomer in solution as shown by (1)H and (31)P NMR spectroscopy. The molecular structures and the binding mode of the ancillary diphosphine ligand(s) in have all been established by X-ray diffraction analyses. The solid-state structure of reveals that the chiral bmf ligand caps one of the metallic faces stereospecifically with the 5-methoxy moiety oriented distal or trans relative to the Ru(6) polyhedral core. The new substitution products are discussed relative to the products obtained from and the related diphosphine ligands dppm, dppe, dppf, and dppbz.

The synthesis and full characterization (mp, NMR, UV/vis, FTIR, and elemental analysis) of 13 bismuth aryloxides are reported. We have prepared bismuth aryloxides with alkyl, aryl, and allylic substituents on the aryl rings. Eleven of these bismuth aryloxides have been characterized with single crystal X-ray diffraction methods. Bismuth-donor interactions (donor = aryl, methoxy) are observed in several cases. Three unexpected bismuth oxo aryloxides (6c, 9c, 11c) were also isolated. Complex C(77)H(102)Bi(4)Br(6)O(8) (6c) results from apparent C-H activation and Bi-C bond formation as a sideproduct in the synthesis of Bi(O-2,6-(i)Pr(2)-4-BrC(6)H(2))(3) (6). Cluster 9c has a Bi(32)O(56) core, and cluster C(90)H(90)Bi(4)Li(2)O(12) (11c) is the second lithium bismuth oxo cluster reported to date.

We report the study of the temporal dependence of the non-linear optical response of novel organic materials in solution. The experimental results of the optical Kerr gate using 70fs pulses show a quasi-instantaneous response for three derivatives of an amino-triazole donor–acceptor system. The non-linearity of the compounds is identified as arising from the electronic contribution to the third-order non-linear susceptibility. The non-linear parameters of each sample were obtained using the optical Kerr response of CS2 as reference.

We present a method for measuring the magnitude and sign of the nonlinear refractive and absorptive coefficients in isotropic media based on vectorial two-wave mixing. The technique consists of the measurement of the self-diffracted signals as a function of the angle between the linear polarizations of two input pulses. The technique was used to investigate the nonlinear optical response of three amino-triazole derivatives in solution, using nanosecond pulses at 532nm. For these samples the results show that nonlinear refraction is isotropic, and that nonlinear absorption is present. Input–output experiments show nonlinear absorption consisting of a combination of saturation and induced absorption. A three-level model for the nonlinear absorption was used to explain the experimental results.

Thermolysis of mixed-metal tetrahedrane cluster HCCo2MoCp(CO)8 (1) with the diphosphine ligand 2,3–bis(diphenylphosphino)maleic anhydride (bma) furnishes the cluster compounds HCCo2MoCp(CO)6[trans-2,3-bis(diphenylphosphino)succinic anhydride] (2), HCCo2MoCp(CO)6(bma) (3), and Co2MoCp(CO)6[μ–C=C(H)CH2C(PPh2)C(PPh2)C(O)OC(O)] (4) in low yields (<13%). The tungsten congener HCCo2WCp(CO)8 (5) reacts with bma to give Co2WCp(CO)6[μ–C=C(H)CH2C(PPh2)C(PPh2)C(O)OC(O)] (6) as the sole isolable product in 3% yield. The new clusters have been fully characterized in solution by IR and NMR spectroscopies, and the solid-state structures of the vinylidene-bridged clusters 4 and 6 established by X-ray crystallography. Clusters 4 and 6 each contain 48e- and exhibit triangular Co2M cores, with a vinylidene moiety that caps one of the Co2M faces. The reactivity differences exhibited by clusters 1 and 5 with bma are contrasted with similar data from the substitution reaction of bma with the related cluster compounds PhCCo2MoCp(CO)8 and PhCCo2WCp(CO)8.

Me3NO activation of the tetrairidium cluster Ir-4(CO)(12) (1) in presence of the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten- 1,3-dione (bpcd) furnishes the bpcd-substituted clusters Ir-4(CO)(10)(bpcd) (3) and Ir-4(CO)(8)(bpcd)(2) (4) as the minor and major products, respectively. Cluster 3 has been isolated as the sole observable product from the reaction of [Ir-4(CO)(11)Br][Et4N] (2) with bpcd in presence of AgBF4 at room temperature. Both 3 and 4 have been isolated and fully characterized in solution by spectroscopic methods. The solid-state structure of 3 reveals that the ancillary bpcd ligand is bound to a single iridium center, with chelating and bridging bpcd ligands found in the X-ray structure of cluster 4. Cluster 4 is unstable at room temperature and slowly loses CO to afford the hydride-bridged cluster HIr4(CO)(4)(mu-CO)(3)(bpcd)[mu-PhP(C6H4)C=C(PPh2)C(O)CH2C(O)] (5). Cluster 5 has been fully characterized in solution by IR and NMR spectroscopies, and the C-H bond activation attendant in the ortho metalation step is shown to occur regioselectively at one of the aryl groups associated with the bridging bpcd ligand. The redox properties of clusters 3-5 have been explored and the electrochemical behavior discussed with respect to extended Huckel MO calculations and related diphosphine-substituted cluster compounds prepared by our groups. (C) 2007 Elsevier B.V. All rights reserved.

The reaction of the pincer diphosphine ligand 4,6-bis(diphenylphosphinomethyl)-m-xylene (dppx) with the metal cluster compounds PhCCo3(CO)9 and Ru6(μ6-C)(CO)17 has been explored. Both clusters react with dppx to afford the simple substitution products [PhCCo3(CO)8]2(dppx) and [Ru6(μ6-C)(CO)16]2(dppx), where two cluster units are tethered by the pincer ligand. The molecular structures of the title products and the 2:1 cluster-pincer ligand stoichiometry have been established by X-ray crystallography. The stability of [PhCCo3(CO)8]2(dppx) and [Ru6(μ6-C)(CO)16]2(dppx) has been investigated under gentle thermolysis conditions (ca. 55–65°C). Both dppx-substituted clusters are unstable with [PhCCo3(CO)8]2(dppx) decomposing and [Ru6(μ6-C)(CO)16]2(dppx) transforming into the diphosphine-bridged cluster Ru6(μ6-C)(CO)15(μ-dppx) as the major observable product. The identity of the latter cluster has been ascertained by IR and NMR spectroscopies and mass spectrometry.

Photochemical activation of the bpcd-chelated cluster 1,1-Os3(CO)10(bpcd) (1) in the presence of P(OEt)3 furnishes the simple substitution product 1,1,2-Os3(CO)9[P(OEt)3](bpcd) (2) initially, followed by the formation of the hydride cluster HOs3(CO)7[P(OEt)3][μ-{PPh(C6H4)}C=C(PPh2)C(O)CH2C(O)] (3). Both new clusters were isolated and characterized in solution by IR and NMR (1H and 31P) spectroscopies, with the solid-state structure of cluster 3 determined by X-ray diffraction analysis. Cluster 3 crystallizes in the triclinic space group P−1, a=9.366(2) Å, b=14.182(4) Å, c=17.672(4) Å, α=87.787(4)°, β=78.488(4)°, γ=71.785(4)°, V=2184.1(9) Å3, Z=2, D cacl=2.123 Mg/m3; R=0.0488, R w=0.1059 for 8527 observed reflections with I > 2σ(I). The presence of the seven-electron ligand μ-P{Ph(C6H4)}C=C(PPh2)C(O)CH2C(O) that caps one of the triangular faces in 3 through both phosphine moieties, the π bond of the dione ring, and an ortho-metalated aryl ligand is established.

Knoevenagel condensation of ferrocenecarboxaldehyde with 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) yields the new diphosphine ligand 2-(ferrocenylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (fbpcd) in near quantitative yield. The reaction of fbpcd with the activated cluster 1,2-Os3(CO)10(MeCN)2 has been examined, with the diphosphine-bridged cluster 1,2-Os3(CO)10(fbpcd) (2b) observed as the major product. Cluster 2b is unstable and transforms into the corresponding chelating isomer 1,1-Os3(CO)10(fbpcd) (2c) on heating. The kinetics associated with the conversion of 2b→2c have been studied over the temperature range of 313-343 K by 1H NMR and UV–vis spectroscopies. On the basis of the observed activation parameters, a nondissociative isomerization process that involves a transient μ2-bridged phosphine moiety is presented. Near-UV irradiation of cluster 2c leads to CO loss and ortho-metalation of the one of the ancillary phenyl groups to give the hydride cluster HOs3(CO)9[μ-PhP(C6H4)CC(PPh2)C(O)CCH(C5H4FeCp)C(O)] (3) as a 45:55 mixture of diastereomers. The fbpcd ligand and clusters 2b, 2c, and 3 have been isolated and characterized in solution by IR and NMR (1H and 31P) spectroscopies, and by X-ray diffraction analysis in the case of the hydride-bridged cluster 3.

The reaction of the diphosphine ligands 1,2-bis(diphenylphosphino)benzene (dppbz) and 1,8-bis(diphenylphosphino)naphthalene (dppn) with the hydride-bridged cluster H4Ru4(CO)12 (1) has been investigated under thermal and Me3NO activation conditions. Both activation methods furnish the diphosphine-substituted clusters 1,1-H4Ru4(CO)10(P–P) (where P–P=dppbz, dppn) as the sole isolable products. The chelating coordination mode adopted by the ancillary diphosphine ligands has been confirmed by NMR spectroscopies and X-ray crystallography. The stability of the new clusters 1,1-H4Ru4(CO)10(dppbz) and 1,1-H4Ru4(CO)10(dppn) has been examined, and both clusters have been found to be stable at elevated temperatures in toluene and extended near-UV photolysis.