Synthesis, Structure and Properties of the First Examples of Hexacoordinate Sn^IV Complexes of Pyrrolyldipyrrins

Abstract

The α-pyrrolyl dipyrrin acted as tridentate ligand to form the first examples of hexacoordinated Sn(IV) complexes under simple reaction conditions. Prior to this report, there is no literature precedence on hexacoordinated metal complex of pyrrolyl dipyrrin ligand. The Sn(IV) complexes were prepared by treating the appropriate meso-aryl substituted -pyrroyl dipyrrin with SnCl 2 in chlorobenzene at reflux followed by silica gel column chromatographic purification. The Sn(IV) complexes were characterized by HR-MS, 1D and 2D NMR spectroscopy and X-ray crystallography. The X-ray structure revealed that the two pyrrolyl dipyrrin ligands were perpendicular to each other and the pyrrolyl dipyrrin ligand forms five and six membered rings upon coordination with Sn(IV) ion. The Sn(IV) complexes absorbs strongly in the region of 500-600 nm and were stable under electrochemical conditions.

Synthesis, Structure, and Properties of Helical Bis-Cu(II) Complex of Linear Hexapyrrolic Ligand

“…In 3-pyrrolyl BODIPYs, the presence of additional pyrrole ring at the α-position of BODIPY resulted in significant bathochromic shifts in absorption and fluorescence bands compared to BODIPYs. , The appended pyrrole in 3-pyrrolyl BODIPYs was very susceptible to functionalization, and the functionalized 3-pyrrolyl BODIPYs have been used as synthons to prepare complex fluorescent systems . We further developed a method to decomplex a BF 2 unit of 3-pyrrolyl BODIPY , to afford α-pyrrolyl dipyrrin which was subsequently used as a ligand to prepare octahedral Sn­(IV) complex . During our studies, we realized that the 3-pyrrolyl BODIPY could be used as a precursor to prepare oligopyrrolic ligand that contains six pyrrole rings.…”

“…24 We further developed a method to decomplex a BF 2 unit of 3-pyrrolyl BODIPY 25,26 to afford α-pyrrolyl dipyrrin which was subsequently used as a ligand to prepare octahedral Sn(IV) complex. 26 During our studies, we realized that the 3-pyrrolyl BODIPY could be used as a precursor to prepare oligopyrrolic ligand that contains six pyrrole rings. Herein, we report the synthesis of linear hexapyrrolic ligand 1 using 3-pyrrolyl BODIPY 3 as a key precursor, and ligand 1 was further used to prepare novel double-helical bis-Cu(II) complex 1-Cu.…”

Substitution at boron in BODIPYs

“…Treatment of F-BODIPYs with BBr 3 was equally successful, with reaction of the corresponding Br-BODIPY with wet acetone providing the parent dipyrrin as its HBr salt. 62 Alternative methods for deprotection of F-BODIPYs, including via use of other Lewis acids, 76,77 Brønsted acids 78 and via treatment with methylboronic acid and TFA are also known. 79 This approach has been key to generating prodigiosene-type complexes whereby a pyrrolide flanks the dipyrrinato unit to create an effective chelation pocket.…”

Synthesis, structure, and properties of palladium(ii) complex of α-formyl pyrrolyl dipyrromethene

“…18 We also developed Lewis acid catalyzed deboronation of 3-pyrrolyl BODIPY 5 to afford free pyrrolyl dipyrrin 19 7 which was used as the ligand to prepare hexacoordinated Sn( iv ) complexes of pyrrolyl dipyrrins 8 . 20 We thought of exploring pyrrolyl dipyrrin 7 containing three pyrrole rings as a ligand to prepare metal complexes that can be used for catalytic applications. We explored pyrrolyl dipyrrin 7 as a ligand to synthesize various metal complexes except metal complex 8 .…”