Synthesis, structures and reduction chemistry of monophthalocyanine scandium hydroxides

Ganga-Sah, Y. and Tajbakhsh, E. and Platel, R.H. and Zhou, W. and Leznoff, D.B. (2019) Synthesis, structures and reduction chemistry of monophthalocyanine scandium hydroxides. Journal of Porphyrins and Phthalocyanines, 23 (11-12). pp. 1592-1602.

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Abstract

The preparation and structural characterization of a pair of scanditun(III) phthalocyanine hydroxide complexes were achieved by reaction of PcScCl with alkali metal alkoxides, likely via hydrolysis of soluble PcSc-alkoxide intermediates. A Sc2Li2 (mu(3)-OH)(4) cubane supported by two distorted Pc rings of the form (PcSc)(2)(mu(3)-OH)(4)Li-2 (THF)(DME) was isolated from the reaction of PcScCl with (LiOPr)-Pr-i, while a simpler alkali-metal-free [Pc2Sc2(mu(2)-OH)(2)(THE)] was obtained from addition of (NaOBu)-Bu-i; both structures are reminiscent of bent metallocenes, with dihedral angles between the two Pc rings of 50.8 and 37.7 degrees respectively. A soluble PcScOH material can also be obtained directly via hydrolysis of insoluble PcScCl in approximately 95:5 THF:water. Reduction of the Pc ring of PcScCl using KC8 is reversible and generates Pc3- and Pc4--containing materials that were characterized via UV-vis spectroscopy and, where appropriate EPR and H-1 NMR spectroscopy; analogous reductions of the PcScOH-based species were irreversible. Exposure of the air-sensitive, reduced PcScCl-based species to ambient atmosphere generated PcScOH materials analogous to the direct hydrolysis route.