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SUMMARY:Preferred isomerism of hydroxy-N\,N’-diarylformamidine derivativ
 es in the solid-state
DTSTART;VALUE=DATE-TIME:20241122T081500Z
DTEND;VALUE=DATE-TIME:20241122T083000Z
DTSTAMP;VALUE=DATE-TIME:20260615T200239Z
UID:indico-contribution-9845@events.saip.org.za
DESCRIPTION:Speakers: David Juma ( University of KwaZulu Natal)\nIntroduct
 ion\nThe flexibility of diarylformamidine ligands to coordinate either as 
 monodentate or as chelating ligands render their respective complexes very
  promising for application in catalysis [1]. N-hydroxy-N\,N’-diarylforma
 midine complexes have been reported by our research group to be significan
 t initiators in ring opening polymerization [2]. In this work\, we explore
  the synthesis and characterization of hydroxy-N\,N’-diarylformamidine d
 erivatives with particular interest in their preferred isomerism in the so
 lid-state.\n\nResults\nSymmetrical and Unsymmetrical N-hydroxyformamidines
  were synthesized and characterized using various spectroscopic techniques
 . The crystals of the compounds obtained underwent X-ray diffraction analy
 sis\, revealing that symmetrical formamidines can adopt both zwitterionic 
 and neutral hydroxy forms\, whereas unsymmetrical compounds exclusively ad
 opt the zwitterionic form in solid state. The zwitterions exhibit Zanti is
 omerism\, while the neutral hydroxy forms exhibit Eanti isomerism. Symmetr
 ical and unsymmetrical compounds with smaller substituents tend to form di
 meric molecular units\, described by an R_2^2 (10) graph set descriptor. I
 n contrast\, unsymmetrical compounds with bulkier substituents form chain-
 like structures. Classical hydrogen bonds (N–H…O\, N—H…N\, N—H
 …O\, and O–H…N) stabilize the crystal packing in dimeric units\, whi
 le C–H…O interactions promote packing in chain-forming molecules. Pair
 wise interaction energy calculations reveal that electrostatic energy (Eel
 e) predominates in the stability of the dimeric pairs\, whereas dispersion
  energy (Edis) is more dominates in chain-like structures.\n \n\nReference
 s\n[1] Akpan ED\, Ojwach SO\, Omondi B\, Nyamori VO.\, New J. Chem. **40**
  (2016) 3499-3510. \n[2] Munzeiwa WA\, Omondi B\, Nyamori VO\, Polyhedron.
  **138** (2017) 295-305.\n\nhttps://events.saip.org.za/event/249/contribut
 ions/9845/
LOCATION:
URL:https://events.saip.org.za/event/249/contributions/9845/
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