Iron amino-bis(phenolate) complexes for the formation of organic carbonates from CO2 and oxiranes

A series of iron(III) compounds supported by tetradentate amino-bis(phenolate) ligands were synthesized and characterized using electronic absorption spectroscopy, magnetic moment measurement and MALDI-TOF mass spectrometry. The solid-state structures of 1 and 2 were determined by X-ray diffraction and reveal iron(III) square pyramidal compounds. The complexes were studied as catalysts for the reaction of carbon dioxide and epoxides in the presence of a co-catalyst, under solvent free conditions to yield cyclic carbonates. Catalytic testing with TBAB as a co-catalyst shows that 4 bearing electron withdrawing groups in the ortho and para-positions of the phenolate ring exhibits the highest catalytic activity. Kinetic studies using 1 revealed that the cycloaddition reaction is affected by temperature as expected and the activation energy for propylene carbonate formation is 98.4 kJ mol−1

Ring-opening polymerization of rac-lactide mediated by tetrametallic lithium and sodium diamino-bis(phenolate) complexes

Lithium and sodium compounds supported by tetradentate amino-bis(phenolato) ligands, [Li2(N2O2BuBuPip)] (1), [Na2(N2O2BuBuPip)] (2) (where [N2O2BuBuPip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4,6-tert-butylphenol), and [Li2(N2O2BuMePip)] (3), [Na2(N2O2BuMePip)] (4) (where [N2O2BuMePip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4-methyl-6-tert-butylphenol) were synthesized and characterized by NMR spectroscopy and MALDI-TOF mass spectrometry. Variable temperature NMR experiments were performed to understand solution-phase dynamics. The solid-state structures of 1 and 4 were determined by X-ray diffraction and reveal tetrametallic species. PGSE NMR spectroscopic data suggests that 1 maintains its aggregated structure in CD2Cl2. The complexes exhibit good activity for controlled ring-opening polymerization of rac-lactide (LA) both solvent free and in solution to yield PLA with low dispersities. Stoichiometric reactions suggest that the formation of PLA may proceed by the typical coordination–insertion mechanism. For example, 7Li NMR experiments show growth of a new resonance when 1 is mixed with 1 equiv. LA and 1H NMR data suggests formation of a Li-alkoxide species upon reaction of 1 with BnOH

The Impact of Expertise on the Capture of Sketched Intentions: Perspectives for Remote Cooperative Design

peer reviewedThe paper describes the way expertise and field-knowledge can impact the transfer of graphical intentions during architectural cooperative design. The analysis of 28 controlled experiments reveals what matters in transmitting architectural intents and more specifically underlines how novices’ intuitive, deductive processes based on previous and embodied experiences interestingly complement experts’ knowledge of the architectural field and its semantics. The results directly inform how we, as researchers, designers and engineers, should take advantage of both novices’ and experts’ strategies to develop tools, methods or interfaces to support next generation cooperative design

Unsocial capital. Patronage and cronysm in postmodern power

Not always the relational capita is also a "social" capital. Often, this type of capital tough composed of bonds and interactions, appears nonetheless as a capital which is profoundly unsocial. This happens in two cases: either when the laces do not bind to each other, or when they bind well between them but do not bind to the wider society in which they are also inserted. It presents itself then, as a capital that binds but not as one that unites, which connects but not that which integrates. It is the capital of linkages and of small groups, which however do not amalgamate into larger forms of cohesion. The illustrative image may be that of many small aggregations that do not however make a single large network. It is the capital of narrow ties rather than relations which are broader and inclusive. Or it is the case of strong ties and closure forms of pseudo-community. In this case that we speak of capital which bonds rather than which bridges, to use an expression which is dear to the dominant literature on the subject . For these reasons, it ends up making more for the convenience "of" the society, than “for" the society and therefore social cohesion and amalgamation are clumped into many small social circles and just for very exclusively selected affinities. The hypothesis that in these pages we intend to support is that the unsocial capital is the product of "certain forms" of relational particularism, which produce a patronage degeneration of power. At question therefore is not relational particularism "in itself", but rather relational particularism "under certain conditions" or "with certain characteristics" which are able to mark a continuum between unsocial capital and forms of patronage (but also nepotistic or familistic) of power. The story of the power of Rome can help us to grasp some of these unexpected relational consequences