title: Synthesis, structure and spectral and electrochemical properties of 3-pyrrolyl BODIPY-metal dipyrrin complexes.
abstract: The stable dipyrrin substituted 3-pyrrolyl BODIPY (α-dipyrrin 3-pyrrolyl BODIPY) was synthesized by oxidation of dipyrromethane substituted 3-pyrrolyl BODIPY with 2,3-dichloro-5,6-dicyano-benzoquinone in CH2Cl2 at room temperature. The α-dipyrrin 3-pyrrolyl BODIPY is characterized by using HR-MS, 1D, 2D NMR and absorption spectroscopic techniques. The absorption spectrum of α-dipyrrin 3-pyrrolyl BODIPY showed a characteristic absorption band at 630 nm and a charge transfer band at 717 nm due to intramolecular charge transfer from the dipyrrin unit to the 3-pyrrolyl BODIPY unit. The 3-pyrrolyl BODIPY-metal dipyrrin complexes (Pd(ii), Re(i) and Ru(ii)) were prepared by treating α-dipyrrin 3-pyrrolyl BODIPY with appropriate metal salts in toluene-triethylamine at 100 °C and purified by silica gel column chromatography. The crystal structure obtained for the 3-pyrrolyl BODIPY-Pd(ii) dipyrrin complex showed that the 3-pyrrolyl BODIPY and metal dipyrrin moieties are aligned to each other with an angle of 41.9°. The absorption studies showed a strong band at ∼620 nm corresponding to 3-pyrrolyl BODIPY moiety and a weak band at ∼530 nm corresponding to metal dipyrrin unit with complete disappearance of the charge transfer band at 717 nm. The complexes are electron deficient and exhibited only reversible/quasi-reversible reductions in cyclic voltammetry.
authors.affiliation: Department of Chemistry, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India. ravikanth@chem.iitb.ac.in.
authors.forename: V
authors.initials: V
authors.lastname: Lakshmi
authors.forename: Way-Zen
authors.initials: WZ
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Ravikanth
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D004563:Electrochemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D056831:Coordination Complexes; D005456:Fluorescent Dyes; D010165:Palladium; D012211:Rhenium; D012428:Ruthenium