Polymer amide as an early topology

Chiral 480 nm absorption in the hemoglycin space polymer: a possible link to replication

A 1494 Dalton hemoglycin space polymer of Glycine₁₈ Hydroxy-glycine₄ Fe₂O₄ termed the "core unit" is part of a polymer of Glycine, Si, Fe and O that forms tubes, vesicles and a lattice structure. It has been isolated from four different CV3 meteorites and characterized by mass spectrometry, FIB/SIMS and X-ray analysis. In quantum calculations (HF and DF wB97X-D 6-31G) the polymer has an absorption at 480 nm that is dependent on rectus "R" (= dextro D) chirality in a hydroxy glycine residue whose C-terminus is bonded to an iron atom. The absorption originates in the Fe II state as a consequence of chiral symmetry breaking. In confirmation of theory, measurements at Diamond Light Source UK, on crystals of hemoglycin derived from Acfer-086 and Sutter's Mill meteorites have shown a strong 483 ± 3 nm absorption that confirms the proposed location of hydroxy glycine residues within the polymer. A high 483 nm to 580 nm absorption ratio points to an "R" chirality excess in hemoglycin, suggesting that 480 nm photons could have provided the energy for its replication in the protoplanetary disc.

Amide Synthesis through the In Situ Generation of Chloro- and Imido-Phosphonium Salts

We describe a methodology for the amidation of carboxylic acids by generating phosphonium salts in situ from N-chlorophthalimide and triphenylphosphine. Aliphatic, benzylic, and aromatic carboxylic acids can be transformed into their amide counter parts using primary and secondary amines. This functional group interconversion is achieved at room temperature in good to excellent yields. Mechanistic work shows the in situ formation of chloro- and imido-phosphonium salts that react as activating agents for carboxylic acids and generate an acyloxy-phosphonium species.