Phosphorus-nitrogen compounds: part 63. Mono- and bis-vanillinatobisferrocenyldispiro(/)cyclotriphosphazenes and their macrocyclic Schiff-bases: synthesis, structural characterization and isomerism
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-h...
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| Published in | New journal of chemistry Vol. 46; no. 21; pp. 1368 - 1378 |
|---|---|
| Main Authors | , , , |
| Format | Journal Article |
| Language | English |
| Published |
CAMBRIDGE
Royal Soc Chemistry
30.05.2022
Royal Society of Chemistry |
| Subjects | |
| Online Access | Get full text |
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| Summary: | 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. |
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| Bibliography: | 12 13 (Fig. S1); the ring conformations of compounds for 2151934 2151933 ) , https://doi.org/10.1039/d2nj00846g 1 H NMR spectral data of the phosphazenes (Tables S1 and S2); the ESI-MS spectrum of compound For ESI and crystallographic data in CIF or other electronic format see DOI Electronic supplementary information (ESI) available: List of 6 and 2151935 9 (Fig. S2-S4); the shapes of the phosphazene rings in these phosphazenes with torsional angles (Fig. S5). CCDC C (decoupled) and 10 |
| ISSN: | 1144-0546 1369-9261 |
| DOI: | 10.1039/d2nj00846g |