Azadipyrromethene Dye Derivatives in Coordination Chemistry: the Structure–Property Relationship in Homoleptic Metal(II) Complexes

Abstract

As a chromophore closely related to dipyrromethene (DPM), the azadipyrromethene (ADPM) family has attracted much interest in the life sciences and optoelectronic fields. A high-yielding microwave-assisted synthesis is reported for new homoleptic complexes of cobalt(II), nickel(II), copper(II) and zinc(II) based on the tetrakis(p-methoxyphenyl)azadipyrromethene ligand 1b. These complexes are compared with other homoleptic complexes of the same metal(II) series based on the tetraphenylazadipyrromethene 1a and also with related BF2(+) chelates (Aza-BODIPYs 6a and 6b) for a better understanding of trends arising from substitution of the chelate and/or the electron-donating effect of the p-methoxy substituents. The electrochemical behavior of the new compounds 2b, 3b, and 5b in dichloromethane revealed two pseudoreversible reductions (2b, -1.09 and -1.25 V vs SCE; 3b, -1.05 and -1.29 V; 5b, -1.13 and -1.25 V) followed by a third irreversible process (2b, -1.78 V; 3b, -1.80 V; 5b, -1.77 V) along with two pseudoreversible oxidations (2b, 0.55 and 0.80 V; 3b, 0.56 and 0.80 V; 5b, 0.55 and 0.80 V) followed by two closely spaced irreversible processes (2b, 1.21 and 1.27 V; 3b, 1.21 and 1.28 V; 5b, 1.22 and 1.25 V). On its side, copper(II) homoleptic complex 4b revealed only one pseudoreversible reduction at -0.59 V followed by three irreversible processes at -0.95, -1.54, and -1.74 V, respectively. The oxidation behavior of this complex exhibited two pseudoreversible processes (0.55 and 0.82 V) and two irreversible processes (1.19 and 1.25 V). The redox processes are assigned and discussed in relation to their photophysical properties. X-ray structures for 1b and related copper(II) complex 2b are also discussed.

Synthesis, spectral-luminescent properties of B(III) and Zn(II) complexes with alkyl- and aryl-substituted dipyrrins and azadipyrrins

“…Alteration of nature of meso spacer by replacement of methyne bridge by nitrogen atom is one of efficient approaches to reach this effect. rins was synthesized [25][26][27][28][29]. Azadipyrrin complexes are characterized, as a rule, by strong absorption in the red spectral region (λ max > 650 nm, ε ~ 75 000-85 000 M -1 cm -1 ), the complexes are of interest for biochemical applications.…”

Synthesis of fused-ring aza-dipyrromethenes from aromatic nitriles

“…The green mixture was cooled back to RT and filtered. The solid was washed vigourously with methanol followed by a single DCM wash to give a purple/brown lustrous powder (4.1 g, 47% This procedure was adapted from the microwave procedure from Bessette et al 2 The azadiisoindolmethine (40-100 mg), DIPEA (2 eq), Zn(OAc) 2 (1.2 eq), n-butanol (3 mL) and a stir bar. The mixture was heated in a microwave reactor at 140 • C for 5 minutes before cooling to RT and evaporating the solvent.…”

Twofac-tricarbonylrhenium(I) azadipyrromethene (ADPM) complexes: ligand-substitution effect on crystal structure

“…Direct observations regarding the modification of ADPM ligand upon complexation can be drawn from comparison of its solid-state structure (Bessette et al, 2012) and those of its rhenium complexes 2and 3. The torsion of the aryl substituents with respect to the ADPM core increases in order to accommodate the fac-Re(CO) 3 unit [tilt angles are in range 19.3 (1)-25.4 (1) for (1) and 19.1 (1)-48.6 (1) for 2and 3, with the higher values corresponding to the tilt of the proximal aryl substituents].…”