Structural dimorphism of N-(3-hydroxysalicylidene)-2,4,6-trimethylaniline

The title compound N-(3-hydroxysalicylidene)-2,4,6-trimethylaniline exhibits dimorphism. The structure of (I) is orthorhombic Pbca with a = 22.222(3), b = 16.200(2), c = 7.596(2) Å, V = 2735(1) ų, and Z = 8. The structure of (II) is monoclinic P2₁/c with a = 11.734(1), b = 15.734(1), c = 7.432(2) Å, = 100.97(1)°, V = 1347.0(5)ų, and Z = 4. The two structures are analyzed in relation with the possibility of an equilibrium between two tautomeric phenol and quinone forms by rapid hydrogen transfer. The molecules associated by intermolecular hydrogen bonds form centrosymmetric dimers. The compounds are thermochromic. The results are compared with the photochromic analog N-(hydroxysalicylidene)-2,4,6-trimethylaniline (compound III) and with the thermochromic one N-(5-hydroxysalicylidene)-2,4,6-trimethylaniline (compound IV). It is concluded that the 3-hydroxyl substituent of the salicylidene moiety enables the intermolecular hydrogen transfer from oxygen to nitrogen.     

Sweat Based-multiplexed Detection of NPY-Cortisol for Disease Diagnostics and Stress Management

Cortisol and Neuropeptide Y(NPY) are chronobiological markers of stress. Non-invasive tracking of these two biomolecules can provide great insight into an individual's physiological and neurological wellbeing. This work presents the development of a platform that tracks the two biomarkers in ultra-low volumes (5 μL) of sweat using electrochemical impedance spectroscopy (EIS). The sensing platform was able to detect both molecules in their relevant physiological ranges (8.16–141.7 ng/mL and 50–200 pg/mL respectively) with good sensitivity and specificity. This platform is envisioned to aid in the monitoring of pathophysiologies of stress-based disorders.