Synthetic and computational studies of organometallic complexes containing low-coordinate group 13 ligands

The work presented in this thesis is concerned with synthetic and computational studies of low coordinate transition metal complexes of boron. New symmetrically bridged boryl complexes of iron and manganese have been prepared and characterised. Information obtained from spectroscopic and structural analyses, together with Density Functional theoretical studies, has been used to investigate the nature of the metal-boron bonds in these complexes. Development of the chemistry of related terminal analogues has also been undertaken. The M-B bonds present in these molecules can be considered mainly o in character, with very little n contribution. Attempts to investigate the chemistry of base-stabilised boryl complexes, using PMe3 and THF as Lewis bases, shows that, while PMe3 adducts with haloboranes are very stable and do not react with metallic fragments, THF complexes give more promising results, especially when THF is also used as a solvent for the reaction. Substitution and abstraction chemistry of the new (mesityloxy)chloroborane (MesO)BCl2 has been analysed. Replacement of the chlorine atom in (ti5-C5H5)Fe(CO)2 B(OMes)Cll by other nucleophiles is possible, thereby generating new asymmetric boryl ligands. Chloride abstraction using NalBAr'J leads to the formation of the fluoroboryl complex (Tf-C5Hs)Fe(CO)2 B(OMes)F possibly via the putative terminal borylene (n5-C5R5XCO)2Fe=B(OMes) Oxidative addition of B-H, B-B and B-X bonds to both d-block (Rh, Pt) and p-block (In, Sn) metals as an alternative pathway to boryl complexes has also been examined. Unfortunately, while many of the reactions appear to give the expected products (on the basis of in situ NMR monitoring), purification difficulties have prevented the isolation of many of these species as pure compounds. DFT studies on terminal boron- aluminium- and gamum containing complexes have been undertaken. Geometry optimisation, molecular orbital composition, bond dissociation energies and bond density partitioning have been investigated in order to probe the nature of the M=E bonds (E = B, Al, Ga) and the dependence of compound stability on both the ancillary metal-bound ligands and on the substituent of the group 13 diyl fragment. The examples considered were diyl complexes of general formula (n5-C5R5KL)2M(EX)1D+, the 'naked' bridging gallium complex ({(CrMes)Fe(CO)2}2Ga + and five gallium carbene complexes of first row transition metals (V, Mn, Fe, Co, Ni), featuring the heterocyclic ligand {:Ga N(Ph)CH 2}

Benzothiazolium-functionalized NU-1000 : a versatile material for carbon dioxide adsorption and cyanide luminescence sensing

The benzothiazolium-decorated NU-1000-BzTz MOF is a versatile material for carbon dioxide storage and cyanide luminescence sensing in aqueous solutions

EFFECTS OF SUPPORT STRUCTURE DYNAMICS ON CENTRIFUGAL COMPRESSOR ROTOR RESPONSE

LectureAccurate modeling of complicated dynamic phenomena characterizing rotating machineries represents a critical aspect in the rotor dynamic field. A correct prediction of rotor behavior is fundamental to identify safe operating conditions avoiding unstable operating range that may lead to erroneous project solution or possible unwanted consequences for the plant. Considering generic rotating machineries as mainly partitioned in four components (rotors, bearings, stator and supporting structure), most research activities have been addressed so far with strong focus more on the single components rather than on the whole system assembly. The importance of a combined analysis of rotors and elastic supporting structure (Kruger 2013) arises with the continuous development of turbo machinery applications, in particular in the Oil & Gas field, where a wide variety of solutions, such as off-shore installations or modularized turbo compression and turbo generator trains, lead to the need of a more complete study not only limited to the rotor-bearing system

Multimodal hybrid 2D networks via the thiol-epoxide reaction on 1T/2H MoS2 polytypes

The study adds a fundamental tile to the still incomplete puzzle of covalent functionalization tools of 2D inorganic networks and describes a protocol where organic moieties are covalently grafted at both phases (1T and 2H) of a CE-MoS2 sample

Two pathways of proton transfer reaction to (triphos)Cu(η1-BH4) via a dihydrogen bond [triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane]

The interaction of alcohols of variable strength with the copper(i) borohydride complex (triphos)Cu(η1-BH4) results in a great variety of DHB complexes which encompass different mechanisms involving M–H and E–H bond (E = B, O) activation steps