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A series of main chain organometallic polymers (MCOPs) containing Re(CO)3Cl(diimine) cores were synthesized. Three different types of polymerization reactions, including Yamamoto coupling, Heck coupling, and a new metal-mediated Schiff base formation/condensation reaction, allowed for the formation of metal polymers with 100% metal complex incorporation and average molecular weights (Mn) ranging from 25 to 850 kDa. Absorption spectroscopy, electrochemistry, and microscopy studies revealed that the type of polymerization effectively governs the physical and chemical properties of the target polymers. The electronic structures of monomeric and dimeric building units of these polymers backbones were probed by DFT and TDDFT computational methods. DFT calculations and electrochemical studies indicate that in all polymers the oxidation and reduction processes take place on Re(I) metal centers and polymer backbones, respectively. Incorporation of metal as an electron donor (D) and organic conjugated backbone as an electron acceptor (A) provides the D-A architecture [ABSTRACT FROM AUTHOR]

A series of dimeric ReI(CO)3 compounds have been prepared by means of a one-pot reaction of [Re(CO)5X] (X = Cl, Br), pyridine-2-carboxyaldehyde, and o-, m-, or p-phenylenediamine. For the m- and p-substituted phenylenediamine reactions, phenyl-bridged bis(pyridine-2-carbaldimine) compounds of the formula [Re(CO)3X]2(μ-PPC) [ 3- 7; X = Cl, Br; μ-PPC = m- or p-phenylene bis(pyridine-2-carbaldimine)] were produced, with m-phenylenediamine forming a mixture of isomers. For reactions with o-phenylenediamine, multiple products formed (compounds 8- 11), which ranged from the desired o-phenylene bis(pyridine-2-carbaldimine) adduct to 2-pyridylbenzimidazole and bridging dipyridinylquinoxaline complexes. An example of each complex was structurally elucidated by single-crystal X-ray methods. The dimeric m- and p-phenylene-bridged Re(CO)3X compounds, including a sulfonate derivative designed to improve solubility, were investigated for possible photophysical applications through the use of UV/Vis spectroscopy and cyclic voltammetry; the study revealed coupling between the rhenium centers. [ABSTRACT FROM AUTHOR]

The new fluorescent chromophore BOPHY can be readily synthesized in two steps from commercially available reagents via the coupling of pyrrole-2-carbox-aldehyde with hydrazine followed by reaction with BF3. The resultant symmetric and dimeric tetracycle is composed of two BF2 units in six-membered chelate rings appended with pyrrole units on the periphery. The quantum yields of fluorescence for the unmodified compound and the tetramethyl variant are near unity, with values of 95 and 92%, respectively, in CH2Cl2. We have probed the electronic structure of this compound via cyclic voltammetry and density functional theory analysis. [ABSTRACT FROM AUTHOR]

Half-hemiporphyrazine macrocycles, which can be called "semihemiporphyrazines", were synthesized using the Re(CO) 3 unit as a templating agent. The products of these template reactions are six-coordinate rhenium complexes, with a facial arrangement of carbonyls, a halide, and a bidentate semihemiporphyrazine chelate that tilts out of the plane of coordination. Three types of semihemiporphyrazines can be produced from these reactions, depending on the alternate heterocycle to the isoindoline unit; structures including pyridine, thiazole, and benzimidazole were formed. The electronic structures of these compounds were probed using spectroscopy as well as density functional theory methods.