An experimental and computational study on isomerically pure, soluble azaphthalocyanines and their complexes and boron azasubphthalocyanines of a varying number of aza units.

Herein, we present a series of isomerically pure, peripherally alkyl substituted, soluble and low aggregating azaphthalocyanines as well as their new, smaller hybrid homologues, azasubphthalocyanines. The focus lies on the effect of the systematically increasing number of aza building blocks [-N[double bond, length as m-dash]] replacing the non-peripheral [-CH[double bond, length as m-dash]] units and their influence on the physical and photophysical properties of these chromophores. The absolute and relative HOMO-LUMO energies of azaphthalocyanines were analyzed using UV-Vis and CV and compared to the density functional theory calculations (B3LYP, TD-DFT). The lowering of the HOMO level is revealed as the determining factor for the trend in the adsorption energies by electronic structure analysis. Crystals of substituted subphthalocyanines, N2-Pc*H2 and N4-[Pc*Zn·H2O], were obtained out of DCM. For the synthesis of the valuable tetramethyltetralin phthalocyanine building block a new highly efficient synthesis involving a nearly quantitative CoII catalyzed aerobic autoxidation step is introduced replacing inefficient KMnO4/pyridine as the oxidant.

Soluble molybdenum(V) imido phthalocyanines and pyrazinoporphyrazines: crystal structure, UV-vis and electron paramagnetic resonance spectroscopic studies.

Soluble alkyl and aryl imido phthalocyanines [Pc(#)Mo(NR)Cl] (R = tBu, Mes) with molybdenum(V) as central metal were prepared and studied by UV-vis and electron paramagnetic resonance (EPR) spectroscopy. As structural analogue to the weakly aggregating, soluble alkyl substituted Pc(#) ligand, a new, more electron deficient octaazaphthalocyanine, the pyrazinoporphyrazine ligand Ppz(#), was designed. The respective alkyl and aryl imido complexes [Ppz(#)Mo(NR)Cl] are the first examples of molybdenum pyrazinoporphyrazines. UV-vis and EPR spectra revealed unexpected differences between the alkyl and the aryl imido complexes, indicating different electronic structures depending on the nature of the axial ligand. The octahedral coordination of the molybdenum atoms by the axial NR and Cl ligands and the equatorial macrocycles could be verified by EPR spectroscopy. This result was also confirmed by the crystal structure of [Pc(#)Mo(NMes)Cl], which crystallizes from CH2Cl2 in the cubic space group Im3.

Axial functionalization of sterically hindered titanium phthalocyanines.

Several axially functionalized, weakly aggregating titanium phthalocyanines (Pc) have been synthesized and characterized. Soluble titanium dichlorido tetrakis-(1,1,4,4-tetramethyl-6,7-tetralino)-porphyrazine [Pc(#)TiCl(2)] (5) has been prepared by reductive cyclotetramerization of the respective dinitrile precursor in the presence of TiCl(4). 5 and the analogous oxido compound [Pc(#)TiO] (1) are versatile starting materials for the formation of other axially functionalized titanium phthalocyanines such as organoimido (6, 7), alkoxido and aryloxido (8, 9), peroxido (10), sulfido (12), disulfido (11), selenido (14) or diselenido (13) species. Furthermore the deprotonated ligand salts [Pc(#)M(2)] (M = Li (2), Na (3), K (4) are described. The reactivity of the titanium compounds was studied in atom group transfer reactions and ethene polymerization. The crystal structures of 5 and the free ligand Pc(#)H(2) are reported. 5 crystallizes from dichloromethane in the cubic space group Im3. The two chlorido ligands exhibit a cis arrangement. The free ligand Pc(#)H(2) crystallizes in the trigonal space group R3.

Synthesis and X-ray crystal structures of imido and ureato derivatives of titanium(IV) phthalocyanine and their application in the catalytic formation of carbodiimides by metathesis from isocyanates.

The imido titanium phthalocyanine complex [PcTi(NDip)] (Dip = 2,6-diisopropylphenyl) 2a was synthesized from [PcTiO] 1 and one eq. of DipNCO. Due to the steric demand of the Dip group, addition of another isocyanate molecule to the Ti = N functionality of 2a does not occur even at high molar ratios of DipNCO. However, 1 reacts with 2 eq. of arylisocyanates containing sterically less demanding aryl groups producing N,N'-diarylureatotitanium(iv)phthalocyanines [PcTi{κ(2)-(NR)C(O)(N'R)}] (R = p-tolyl (Tol) 3a or mesityl (Mes) 3b). The N,N' coordination (III) of the ureato ligand in 3a and 3b was proven by a single set of resonances for the aryl groups in their (1)H-NMR spectra. An N,O coordination (IV) can therefore be excluded. This is also confirmed by the X-ray crystal structure of 3a. Upon heating [PcTiO] and an excess of aryl isocyanates for 6 days, a steady evolution of CO(2) was observed and a white precipitate, identified as the corresponding diarylcarbodiimides (V), could be isolated. Therefore this reaction was applied in the metathetic conversion of two isocyanate molecules into diarylcarbodiimides (V) and CO(2). Additionally, imido titanium Pc's 2b (R = tBu) and 2c (R = Mes) were prepared by a more general synthetic strategy, reacting the potassium salt of the ligand PcK(2) with appropriate imido titanium precursors.

Synthetic, spectroscopic, and structural studies on organoimido molybdenum, tungsten, and rhenium phthalocyanines.

Unprecedented imido phthalocyaninato complexes of pentavalent refractory metals [PcM(NR)Cl] (M = Mo, W, Re; R = tBu: 1, 3, 6, Mes: 2, 4, 7 or Ts: 5) have been synthesized by reductive cyclotetramerization of phthalonitrile in the presence of appropriate bis(imido) complexes of Mo, W and Re as templates. While d(1) Mo(V) and W(V) species 1-5 show distinctive EPR spectra corresponding to metal centered radicals with hyperfine coupling of two magnetically non-equivalent nitrogen atoms (4 equatorial and 1 axial N), corresponding d(2) Re(V) compounds 6 and 7 are diamagnetic. [PcMo(NtBu)Cl] 1 crystallizes from 1-chloronaphthalene in the tetragonal space group P4/n. The molecular structure reveals, that the metal center is located above the plane of the equatorial N4 and displaced towards the axial π-donor ligand. Due to the thermodynamic trans effect the Mo-Cl bond trans to the imido group is elongated to about 2.600(2) Å.