Synthesis and crystal structures of 5,5'-(propane-2,2-di-yl)bis-(2-hy-droxy-benzaldehyde) and 5,5'-(propane-2,2-di-yl)bis-(2-hy-droxy-isophthalaldehyde).

Rosario C Sausa,Dominika N Lastovickova,John J La Scala

doi:10.1107/s2056989018016316

Rosario C Sausa, Dominika N Lastovickova + Show 1 more

Open Access

https://doi.org/10.1107/s2056989018016316

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Abstract

The title compounds 5,5'-(propane-2,2-di-yl)bis-(2-hy-droxy-benzaldehyde), C17H16O4, (1), and 5,5'-(propane-2,2-di-yl)bis-(2-hy-droxy-isophthalaldehyde), C19H16O6, (2), crystallize with one mol-ecule in the asymmetric unit. In mol-ecule (1), a >C(CH3)2 group bridges two nearly planar salicyl-aldehyde groups [r.m.s deviations = 0.010 (1) and 0.025 (2) Å], each comprising a planar phenyl ring bonded with a hydroxyl and an aldehyde group. Similarly, compound (2) has the same bridging group, but it connects two nearly planar appendants [r.m.s deviations = 0.034 (1) and 0.035 (1) Å], each comprising a phenyl ring bonded with a hydroxyl and two aldehyde groups. Mol-ecule (1) exhibits a bridge angle of 109.5 (2)° with the salicyl-aldehyde planes subtending a dihedral angle of 88.4 (1)°. In contrast, mol-ecule (2) presents a bridge angle of 108.9 (2)° with its appendants subtending a dihedral angle of 79.6 (3)°. Both mol-ecules exhibit two intra-molecular O-H⋯O hydrogen bonds involving the phenolic H atoms and carboxyl O-atom acceptors. In the crystal of (2), O-H⋯O hydrogen bonds between one of the hydroxyl H atoms and a carboxyl O atom from a symmetry-related mol-ecule form a chain along [10]. In addition, (2) exhibits a strong visible luminescence when excited with ultraviolet radiation.

Highlights

The title compounds 5,50-(propane-2,2-diyl)bis(2-hydroxybenzaldehyde), C17H16O4, (1), and 5,50-(propane-2,2-diyl)bis(2-hydroxyisophthalaldehyde), C19H16O6, (2), crystallize with one molecule in the asymmetric unit
In molecule (1), a >C(CH3)2 group bridges two nearly planar salicylaldehyde groups [r.m.s deviations = 0.010 (1) and 0.025 (2) A ], each comprising a planar phenyl ring bonded with a hydroxyl and an aldehyde group
Compound (2) has the same bridging group, but it connects two nearly planar appendants [r.m.s deviations = 0.034 (1) and 0.035 (1) A ], each comprising a phenyl ring bonded with a hydroxyl and two aldehyde groups

Summary

Chemical context

As polymers play an undeniable role in our everyday lives, extensive resources and safety evaluations are devoted toward the development and marketing of the most suitable and effective polymer species for a given application (Andrady & Neal 2009; Fenichell 1996; Teegarden 2004) Bisphenols, salicylaldehydes, and their derivatives have fueled much interest in recent years because they are key precursors for many present and future compounds. As part of our ongoing work on the synthesis and characterization of novel compounds, as well as our effort to eliminate or replace toxic reagents with greener chemicals in the polymer production process, we have synthesized the title compounds, 5,50-(propane-2,2-diyl)bis(2hydroxybenzaldehyde (1) and 5,50-(propane-2,2-diyl)bis(2hydroxyisophthalaldehyde (2) These precursor compounds present a >C(CH3) group that bridges two salicylaldehyde moieties (1) or two phenyl groups with an hydroxyl and two. Molecule (2) presents two intramolecular hydrogen bonds involving the phenolic hydrogen atoms with the carboxyl O-atom acceptors (Table 2), similar to (1)

Structural commentary

Synthesis and crystallization