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Ignition in low temperature combustion engines is governed by a coupling between low-temperature oxidation kinetics and diffusive transport. Therefore, a detailed understanding of the coupled effects of heat release, low-temperature oxidation chemistry, and molecular transport in cool flames is imperative to the advancement of new combustion concepts. This study provides an understanding of the low temperature cool flame behavior of butane isomers in the counterflow configuration through the addition of ozone. The initiation and extinction limits of butane isomers’ cool flames have been investigated under a variety of strain rates. Results revealed that, with ozone addition, establishment of butane cool diffusion flames was successful at low and moderate strain rates. iso-Butane has lower reactivity than n-butane, as shown by higher fuel mole fractions needed for cool flame initiation and lower extinction strain rate limits. Ozone addition showed a significant influence on the initiation and sustenance of cool diffusion flames; as ozone-less cool diffusion flame of butane isomers could not be established even at high fuel mole fractions. The structure of a stable n-butane cool diffusion flame was qualitatively examined using a time of flight mass spectrometer. Numerical simulations were performed using a detailed chemical kinetic model and molecular transport to simulate the extinction limits of the cool diffusion flames of the tested fuels. The model qualitatively captured experimental trends for both fuels and ozone levels, but over-predicted extinction limits of the flames. Reactions involving low-temperature species predominantly govern extinction limits of cool flames. The simulations were used to understand the effects of methyl branching on the behavior of n-butane and iso-butane cool diffusion flames.

Recent developments in the chemistry of homo- and heterometallic clusters of Iron, Cobalt and Nickel triads substituted with alkynes and related ligands are examined. New synthetic procedures, bonding modes and structural arrangements have been found. The old and recent applications of these clusters are discussed.

The industrial processes of starch cationization are widely used and the workers must protect their health from the potential presence of toxic species, such as 2,3-epoxypropyltrimethylammonium chloride (ETA or Quab 151®) or 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA or Quab 188®) used during the industrial processes. In this study, a sensitive and fast chromatographic method for the identification and determination of these toxic species in samples placed in fixed air sampling positions near to the reactor of starch processing has been developed and fully validated. The method is based on hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry detection. The limits of detection are 3.0 ng mL−1 and 1.0 ng mL−1 for ETA and CTA, respectively, and the RSD% of the intraday (n = 5) and the interday (n = 35) precision of concentration determination are lower than 3.4% and 6.1%, respectively. The solid–liquid extraction procedure employed here is very simple (sonication) and fast (5 min) and allows obtaining reliable recovery values greater than 91.0%. No evidence of statistically significant matrix effects (at a 95% of confidence level) during the mass spectrometry analysis has been found. The method has been successfully applied to filter samples used in routine controls for the safety of workers involved in these type of industrial processes.

The reactions of the complexes Fe3(CO)12, H2FeRu3(CO)13, H2Ru4(CO)13 and CpNiRu3(H)3(CO)9 with 2(diphenylphosphino)ethyl-triethoxysilane give considerable yields of the complexes Fe3(CO)10L2 (1), H2FeRu3(CO)10L2 (2), Ru4(CO)10L3 (3) and CpNiRu3(H)3(CO)7L2 (4) where L = Ph2PCH2CH2Si(OEt)3. The complexes (1–3) have been characterized by analytical and spectroscopic techniques. The structure of (4) has been determined by X-ray analysis. The presence of a phosphine containing the –Si(OEt)3 group has been exploited for grafting complexes (3) and (4) on the mesoporous SBA-15 and the resulting inorganic–organometallic materials have been characterized by means of ICP-MS, FT-IR, DR-UV–vis spectroscopy, XRD and textural analysis.

The complex Co2(CO)6[μ-η2-(H3CC CCH2CH2OH)] (1) with the ligand 3-pentyn-1-ol (pol) has been synthesized following established procedures. Its structure has been determined by X-ray analysis. The complex Co2(CO)6(mbo) (mbo = 2-methyl-3-butyn-2-ol, HC CC(CH3)2OH), (3), along with the already known Co2(CO)6(bud) (bud = 1,4-butyn-diol, HOCH2C CCH2OH) (2), and Co2(CO)8 were reacted with 2(diphenylphosphino)ethyl-triethoxysilane [Ph2PCH2CH2Si(OCH2CH3)3] (dpts) and tris(hydroxymethyl)phosphine [P(CH2OH)3] (thp). With dpts, mono- and di-substituted complexes were obtained: these were characterized by analytical and spectroscopic techniques. The structures of Co2(CO)6(dpts)2 (5) and of Co2(CO)4(pol)(dpts)2 (8) have been determined by X-ray analysis. Complex (1) was reacted with 3-(triethoxysilyl)propyl isocyanate [(H3CCH2O)3Si(CH2)3NCO] (tsi): the new complex Co2(CO)6[H3CC CCH2CH2OC( O)NH(CH2)3Si(OCH2CH3)3] (9) was obtained and spectroscopically characterized. The complex has also been reacted with tetraethyl orthosilicate (teos); a new inorganic–organometallic material was obtained. Complex (5) has been grafted on the mesoporous material SBA-15. The hybrid inorganic–organometallic materials obtained have been characterized by inductively coupled plasma-mass spectrometry (ICP-MS), infrared spectroscopy (FT-IR) under vacuum conditions, X-ray diffraction (XRD) and scanning electron microscopy coupled to EDS probe (SEM–EDS).

The reaction of Ru3(CO)12 with 2(diphenylphosphino)ethyl-triethoxysilane (DPTS) in hydrocarbons, leads to the functionalized Ru3(CO)12−n [Ph2P(CH2)2Si(OEt3)] n (n = 1,2) complexes. The complex with two phosphine substituents was chemically anchored on mesoporous silicas, SBA-15 and MCM-41, in order to obtain two hybrid materials characterized by a different localization of the metal centre on the surface of the porous supports. A detailed investigation of the cluster, before and after chemical anchoring on the mesoporous silicas, was pursued. Particular attention was also devoted to the study of the morphological, structural and textural properties of the metal-functionalised silicas (Ru/SBA-15 and Ru/MCM-41) by infrared spectroscopy (FT-IR), scanning electron microscopy, X-ray diffraction and N2 physisorption analysis.

The reactions of Fe3(CO)12 with 2-methyl-3-butyn-2-ol and 3-pentyn-1-ol in CH3OH/KOH solution lead, respectively, to the binuclear complex Fe2(CO)6(μ-CO)(μ-η2-[HCC{ C(CH3)2}C( O)(OCH3)]) (as the main product) and to the closed trinuclear hydridic complex (μ-H)Fe3(CO)9(μ3-η3-[H3CCC(CH2)(CH2)CO]) (as the unique product). The oxygenated ligands of these complexes are formed, respectively, by coupling of a formerly coordinated CO with a methoxy group and by coupling of a formerly coordinated CO with a deoxygenated alkynic residual.

The thermal reactions of 2-methyl-1-hexen-3-yne [CH3CH2C≡CC(=CH2)CH3, metey] with Fe3(CO)12 have been studied: cluster opening or fragmentation and alkyne dimerization occur. Main products are the open triangular isomers [Fe3(CO)6(μ-CO)2{CH3(=CH2)CC(Et)C(Et)C(=CH2)CH3}] (complex 3a) and [Fe3(CO)6(μ-CO)2{C(Et)CCH3(=CH2)C(Et)CCH3(=CH2)}] (complex 3b). The structure and isomerism of the complexes has been confirmed by X-ray studies. The minor products of the reaction have been characterized by spectroscopic techniques. An attempt at exploiting the reactivity of the “free” C=C bonds of the coordinated ene-yne was made: complex 3a was reacted with styrene under thermal conditions. Unexpectedly considerable yields of the closed triangular cluster [Fe3(CO)6{EtC2C(=CH2)CH3}2] (complex 5) have been obtained. This behaviour had not been previously observed. The unprecedented structure of complex 5 has been confirmed with an X-ray study.

The title complex is the main product of the reaction of Fe3(CO)12 with isopropenylacetylene in basic methanolic solution (followed by acidification); it is obtained upon carbon–carbon bond forming and dimerization of the alkyne. The same complex is also obtained by reacting Fe3(CO)12 in CH3OH/KOH solution with 2-methyl-hex-1-en-3-yne; carbon–carbon bond cleavage presumably occurs to form isopropenylacetylene, which then reacts with the iron carbonyl. The unprecedented structure of the complex has been determined with a X-ray diffraction analysis.

Ru3(CO)12 has been reacted with the compounds hex-1-en-3-yne [EtC≡CCH=CH2], 2-methyl-hex-1-en-3-yne [EtC≡CC(=CH2)CH3] and with 3(ethoxy-silyl)propyl isocyanate [(EtO)3Si(CH2)3NCO] and the compound tb [(EtO)3Si(CH2)3NHC(=O)OCH2C≡CCH2OC(=O)NH(CH2)3Si(OEt)3] in hydrocarbon solution. Some reactions in CH3OH/KOH solution (followed by acidification) have also been performed. The main products of the reactions with ene-ynes are the clusters Ru3(CO)6(μ-CO)2L2 (L = C6H8, C7H10) and their demolition products, the “ferrole” Ru2(CO)6L2 complexes. One of the isomers of Ru3(CO)6(μ-CO)2L2, and Ru2(CO)6L2 (L = C7H10) have been reacted with vinyl-triethoxysilane [(EtO)3SiCH=CH2]: these reactions did not afford complexes containing new carbon–carbon bonds or triethoxy-silyl groups. Only polymerization of vinyl-triethoxysilane occurred. The reactions of Ru3(CO)12 with triethoxysilyl-propyl-isocyanate and tb (in the presence of Me3NO) lead to the same products, that is the isomeric complexes (μ-H)Ru3(CO)9[C=N(H)(CH2)3Si(OEt)3] with a “perpendicular” ligand (complex 3, as proposed on the basis of spectroscopic results) and (μ-H)Ru3(CO)9[HC=N(CH2)3Si(OEt)3] with a “parallel” ligand (complex 4, as confirmed by a X-ray analysis). The reaction pathways leading to these products are discussed. Complex 4 has been reacted with tetraethyl orthosilicate and the resulting material has been characterized. These reactions are part of a study on the synthesis of inorganic-organometallic materials through sol–gel techniques.

Co2(CO)8 has been reacted with but-2-yn-1,4-diol (BUD) and the reactivity of the resulting complex Co2(CO)6(HOCH2C≡CCH2OH) (complex 1) is discussed. Complex 1 has been reacted with all the components used in the synthesis of sol-gel materials based on tetraethyl-orthosilicate (TEOS) with the aim at obtaining evidences for the processes occurring during the formation of inorganic-organometallic sol-gel materials containing BUD. Reaction pathways are discussed.

The title compound has been obtained in considerable yield by reacting Ru3(CO)12 with 2-pentynal-diethyl-acetal [CH3CH2C CC(H)(OEt)2] (PDA) in hydrocarbon solvents. The X-ray analysis shows that the title complex belongs to the well known family of the flyover derivatives. Some X-ray structural studies have been reported, many years ago, on di-iron flyover complexes; in contrast only a few examples of diruthenium derivatives have been structurally characterized. The complex contains ethoxy-groups which could potentially undergo hydrolysis in the presence of tetraethyl-orthosilicate (TEOS) in the presence of catalysts. Reactions of complex Ru2(CO)6[μ-η4-{EtC2C(H)(OEt)2}CO{EtC2C(H)(OEt)2}] with TEOS in the presence of HCl or of NaF (as catalysts) have been attempted. An inorganic-organometallic sol-gel material containing the skeleton of the complex has been obtained and characterized with IR-Raman, XRD on powders and SEM microscopy.

The reactions of Fe3(CO)12 with but-2-yn-1,4-diol (BUD), 1,4-dichloro-but-2-yne (DCB), propargyl alcohol (PA) and propargyl chloride (PC) in KOH/CH3OH solutions (followed by acidification with HCl) and under thermal conditions have been examined. The complex Fe2(CO)6{H2CCCCH2} is the main product of the reactions with BUD or DCB in all conditions. The complexes Fe2(CO)6{H2CCC(H)C(OMe)O} and Fe3(CO)10{H2CCC(H)C(O)C{CH2(O)CH3}CCH2} are the main products obtained respectively in the reactions with propargyl chloride (PC) or propargyl alcohol (PA) in basic methanolic solution. The structures of the three complexes have been determined by means of X-ray analysis. Complex Fe2(CO)6{H2CCCCH2} contains a butatrienyl ligand in an uncommon structural arrangement. The formation of complex Fe2(CO)6{H2CCC(H)C(OMe)O} requires CO and methanol activation; its ferrole like structure contains a coordinated acetate group. Complex Fe3(CO)10{H2CCC(H)C(O)C{CH2(O)CH 3}CCH2} contains one Fe(CO)4 and one Fe2(CO)6 fragments linked through a carbon atom chain derived from the insertion of CO and dimerization of propargyl alcohol (with substitution of OCH3 from methanol in the place of OH). Comments on the syntheses and on the reaction pathways leading to the complexes are made.

The title complex is obtained by reacting Ru3(CO)12 with 1,4-dichloro-but-2-yne (ClCH2C CCH2Cl, DCB) in CH3OH/KOH solution (followed by acidification with HCl). The X-ray structure analysis shows that (μ-H)2Ru3(CO)9{μ3-η2-[H2C C(H)CCC( O)OCH3]} complex contains a “parallel” ene-yne acetyl substituent, H2C C(H)C CC( O)OCH3; the formation of such a ligand starting from DCB is – to our knowledge – unprecedented. The synthesis of complex (μ-H)2Ru3(CO)9{μ3-η2-[H2C C(H)CCC( O)OCH3]} occurs through the activation of CO and methanol. This process has been found for other reactions of functionalized alkynes with M3(CO)12 carbonyls (M = Fe, Ru) under basic methanolic conditions. The known hydridic cluster, (μ-H)Ru3(CO)9[μ3-η3-(MeCCHCH)] has been identified as the minor reaction product.

The reaction of Ru3(CO)12 with but-2-yn-1,4-diol (HOCH2CCCH2OH, BUD) in CH3OH/KOH followed by acidification with HCl leads to four products, one of which has been identified as the title complex (μ-Cl)Ru3(CO)9[μ3-η4-H2CCC(H)CH2]. This is an open cluster containing a bridging Cl atom on the open side and a C4H5 moiety bound to all the metals. The structure of the complex has been determined by X-ray analysis. The thermal reaction of Ru3(CO)12 with BUD has been revisited for a comparison with the results in alkaline solution. The main product is the allylic derivative HRu3(CO)9[HCCHCCHO].

The title complex (μ-H)Ru3(CO)9(μ3-η3-C3H3) has been obtained following two different reaction pathways: one is the deamination of diethylaminopropyne, HCCCH2NEt2, in the presence of Ru3(CO)12 under thermal conditions. The other is the reaction of trimethylsilylpropargyl alcohol, (HO)H2CCC(SiMe3) (TSPA), with Ru3(CO)12. The complex is obtained both under thermal conditions and in the reaction of the carbonyl with TSPA in CH3OH/KOH (followed by acidification). Other reaction products, deriving from the loss of Me3Si and of HCHO fragments from TSPA, have also been characterized. Complex (μ-H)Ru3(CO)9(μ3-η3-C3H3) has been spectroscopically characterized and its crystal structure was determined by an X-ray analysis. An isosceles triangle of Ru atoms with an edge bridged by an H atom, is coordinated by an allylic moiety σ-bonded to two Ru atoms and π-interacting with the third Ru atom.

Recent developments in the chemistry of homo- and heterometallic clusters of Iron, Cobalt and Nickel triads substituted with alkynes and related ligands are examined. New synthetic procedures, bonding modes and structural arrangements have been found. The old and recent applications of these clusters are discussed.

The triruthenium complexes containing alkynols ligands have been reacted with 2(diphenylphosphino)ethyl-triethoxysilane (dpts), obtaining novel chemically stable disubstituted complexes. The same disubstituted Ru complexes above described were also synthesized following another approach based on the reaction from the phosphine substituted complex Ru3(CO)10(dpts)2 and the same alkynols ligands used to obtain the above triruthenium complexes. One of these stable complexes, the HRu3(CO)7[C≡C(Me)2(OH)](dpts)2 compound was grafted on the mesoporous silica SBA-15 and on γ-Al2O3 surface in order to obtain novel hybrid materials to employ in heterogeneous catalysis. The resulting materials have been characterized by multidisciplinary approach based on inductively coupled plasma-mass spectrometry (ICP-MS), FT-IR, XRD, physisorption measurements and DR-UV–Visible spectroscopy. Novel chemically stable phosphine-substituted ruthenium clusters containing alkynols ligands have been prepared following two different synthetic approaches. One of these complexes have been anchored on SBA-15 and alumina supports, obtaining chemically stable organic/inorganic hybrid materials to employ in heterogeneous catalysis field.