Phosphorus-nitrogen compounds: part 63. Mono- and bis-vanillinatobisferrocenyldispiro(/)cyclotriphosphazenes and their macrocyclic Schiff-bases: synthesis, structural characterization and isomerism

• Published in: New journal of chemistry 2022-05, Vol.46 (21), p.1368-1378
• Main Authors: Tümer, Yasemin, Asmafiliz, Nuran, K l ç, Zeynel, Hökelek, Tuncer
• Format: Article
• Language: English
• Subjects: Atomic properties; Crystal structure; Imines; Nitrogen compounds; NMR spectroscopy; Optical properties; Phosphazene; Potassium; Potassium salts; Structural analysis; Substitution reactions
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d2nj00846g

In this study, mono- and bis-vanillinato-ferrocenyldispirophosphazenes and their Schiff-bases were obtained to investigate the optical and structural properties of cyclotriphosphazenes with stereogenic P-atoms. Accordingly, substitution reactions of two equimolar amounts of the potassium salt of 4-hydroxy-3-methoxybenzaldehyde (potassium vanillinate; KOAr) with one equimolar dichloro trans - ( 1 and 2 ) and cis -ferrocenyldispirocyclotriphosphazenes ( 3 and 4 ) yielded bis-vanillinato trans - ( 5 and 6 ) and cis -dispirocyclotriphosphazenes ( 8 and 9 ), respectively. In contrast, using equimolar amounts of trans - ( 2 ) and cis -dispirocyclotriphosphazenes ( 4 ) with an equimolar amount of KOAr produced the corresponding mono-vanillinato ferrocenyldispirocyclotriphosphazenes, 7 and 10 . In addition, condensation reactions of bis-vanillinato trans / cis -dispirophosphazenes ( 5 , 6 , 8 and 9 ) and 1,4-diaminobutane gave rise to novel macrocyclic phosphazene Schiff bases, 11 , 12 , 13 and 14 . The characterization of macrocyclic Schiff bases via 1 H, 13 C and 31 P NMR spectroscopy showed that they were present in solution as a mixture of ZZ ( syn - syn ), ZE ( syn - anti ) and EE ( anti - anti ) isomers. The molecular and crystal structures of bis-vanillinato trans - ( 6 ) and cis - ( 9 ), and mono-vanillinato cis -dispirophosphazenes ( 10 ) were elucidated using the X-ray diffraction technique and their absolute configurations were determined as RR , SR and RS , respectively. All dispirophosphazenes have two stereogenic P-atoms, except 10 . In addition to two stereogenic P-atoms, mono-vanillinato phosphazene ( 10 ) also has a pseudo-asymmetric P-center. Compound 10 was proven to be chiral using the CSA-added 31 P NMR spectrum. Mono/bis-vanillinato ferrocenyldispirocyclotriphosphazenes and Schiff-bases were obtained. Structures of the compounds were determined using spectroscopic methods. Absolute configurations of three compounds were defined by X-ray crystallography.