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There is considerable interest in MnOH x moieties, particularly in the stepwise changes in those O–H bonds in tandem with Mn oxidation state changes. The reactivity of aquo-derived ligands, {MOH x }, is also heavily influenced by the electronic character of the other ligands. Despite the prevalence of oxygen coordination in biological systems, preparation of mononuclear Mn complexes of this type with all O-donors is rare. Herein, we report several Mn complexes with perfluoropinacolate (pin F ) 2− including the first example of a crystallographically characterized mononuclear {Mn( iii )OH} with all O-donors, K 2 [Mn(OH)(pin F ) 2 ], 3. Complex 3 is prepared via deprotonation of K[Mn(OH 2 )(pin F ) 2 ], 1, the p K a of which is estimated to be 18.3 ± 0.3. Cyclic voltammetry reveals quasi-reversible redox behavior for both 1 and 3 with an unusually large Δ E p , assigned to the Mn( iii / ii ) couple. Using the Bordwell method, the bond dissociation free energy (BDFE) of the O–H bond in {Mn( ii )–OH 2 } is estimated to be 67–70 kcal mol −1 . Complex 3 abstracts H-atoms from 1,2-diphenylhydrazine, 2,4,6-TTBP, and TEMPOH, the latter of which supports a PCET mechanism. Under basic conditions in air, the synthesis of 1 results in K 2 [Mn(OAc)(pin F ) 2 ], 2, proposed to result from the oxidation of Et 2 O to EtOAc by a reactive Mn species, followed by ester hydrolysis. Complex 3 alone does not react with Et 2 O, but addition of O 2 at low temperature effects the formation of a new chromophore proposed to be a Mn( iv ) species. The related complexes K(18C6)[Mn( iii )(pin F ) 2 ], 4, and (Me 4 N) 2 [Mn( ii )(pin F ) 2 ], 5, have also been prepared and their properties discussed in relation to complexes 1–3. 

Zinc(II) complexes of azadipyrromethenes are non-planar chromophores with strong absorption in the visible to NIR and are promising n-type materials for organic solar cells. To increase solubility and tune their properties, we incorporated hexyl or hexyloxy solubilizing groups either on the distal or proximal phenyls of bis[2,6-diphenylethynyl-1,3,7,9-tetraphenyl azadipyrromethene] zinc(II) (Zn(WS3)2). Crystal structures confirm the typical distorted tetrahedral geometry for these types of complexes and show that the solubilizing groups on the distal phenyls extend away from the conjugated core whereas groups on proximal phenyls interact with the other ligand. Differential scanning calorimetry measurement indicated that crystals of distal-substituted complexes have two endothermic peaks: solubilizing groups ‘melting’ and complex melting, whereas the proximal substituted complexes show one exothermic crystallization peak and one endothermic melting peak. Electrochemical and optical properties varied as expected for ADP-based complexes: the presence of electron rich groups at the proximal substitutions resulted in lower oxidation potentials, higher HOMO levels, red-shifted absorption and lower optical gap than distal substitutions, and the effect was greater for hexyloxy than hexyl. Upon thermal annealing, films of the hexyloxy-substituted complexes strongly aggregated and showed crystal features under a polarized microscope, indicating that hexyloxy groups drive ordered self-assembly, especially when placed on distal phenyls. The ability to guide solid-state self-assembly of these non-planar chromophores using solubilizing groups have the potential to improve their charge carrier mobility and performance in opto-electronic applications such as organic solar cells, and photodetectors. 

2-R-1 H -1,3-Benzazaphospholes (R-BAPs) are an interesting class of σ 2 P heterocycles containing PC bonds. While closely related 2-R-1,3-benzoxaphospholes (R-BOPs) have been shown to be highly photoluminescent materials depending on specific R substituents, photoluminescence of R-BAPs has been previously limited to an example having a fused carbazole ring system. Here we detail the synthesis and structural characterization of a new R-BAP (3c, R = 2,2′-dithiophene), and compare its photoluminescence against two previously reported R-BAPs (3a, R, R′ = Me and 3b, R = 2-thiophene). The significant fluorescence displayed by the thiophene derivatives 3b ( φ = 0.53) and 3c ( φ = 0.12) stands in contrast to the weakly emissive methyl substituted analogue 3a ( φ = 0.08). Comparative computational investigations of 3a–c offer insights into the interplay between structure–function relationships affecting excited state relaxation processes. 

An iron complex with diphosphorus coordinated sideways in a motif similar to alkynes has been synthesized and characterized.