Emissive Chromium(III) Complexes with Substituted Arylethynyl Ligands

Abstract

Arylethynylchromium(III) complexes of the form trans-[Cr(cyclam)(CCC(6)H(4)R)(2)]OTf (where cyclam = 1,4,8,11-tetraazacyclotetradecane, R = H, CH(3), or CF(3) in the para position, and OTf = trifluoromethanesulfonate) have been prepared and characterized by IR spectroscopy and X-ray diffraction. The complexes are emissive with excited-state lifetimes in a deoxygenated fluid solution between 200 and 300 micros.

Synthesis and Investigation of Macrocyclic CrIII Bis(alkynyl) Complexes: Structural and Spectroscopic Properties

“…Based on these findings and previous studies, the observed emissions are assigned as 2 T 1g → 4 A 2g ( O h ), due to the redshift of the emissions compared to value of the traditional 2 E g → 4 A 2g emission, closer to 700 nm , . Theory suggests that assignment as 2 T 1g emitters implies a difference in π effects of the axial and equatorial ligands, such as a tetraamine complex (σ‐donating) with two π‐donors in the axial positions , . It is well established that the acetylide ligands are π‐donating in metal alkynyl complexes, and this is especially true with an electron deficient Cr III center …”

Synthetic and structural studies of mono-acetylide and unsymmetric bis-acetylide complexes based on CoIII-cyclam

“…In addition to the aforementioned study of Ru 2 -based acetylides, our laboratory has investigated a number of M III -cyclam (M = Cr, Fe and Co; cyclam = 1,4,8,11tetraazacyclotetradecane) based acetylide complexes, and elucidated their structural and voltammetric properties [34][35][36][37]. It should be noted that other laboratories have also explored the acetylide chemistry of M III -cyclam complexes [38][39][40][41][42][43]. [45].…”

The overlooked NIR luminescence of Cr(ppy)3

“…Similarly, complexes trans-[Cr(cyclam)(CC-C 6 H 4 R) 2 ] + appear to be photostable. 46 In CH 2 Cl 2 , some photoreactivity is observed for fac-Cr(ppy) 3 (ESI, Fig. S20).…”