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Systematic investigation of new alkaline earth phosphonates based on the linker molecule N,N’‐4,4’‐bipiperidine‐bis(methylenephosphonic acid)
Author(s) -
Steinke Felix,
Stock Norbert
Publication year - 2021
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000390
Subject(s) - ionic radius , alkaline earth metal , metal , chemistry , molecule , crystallography , lanthanide , ionic bonding , ion , organic chemistry
A systematic study of the systems M 2+ /H 4 L/KOH/H 2 O, with M 2+ =Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ and H 4 L=N,N’‐4,4’‐bipiperidine‐bis(methylenephosphonic acid) was carried out using high‐throughput methods, including a temperature gradient oven. Overall, six new alkaline earth phosphonates were discovered and structurally characterised by single‐crystal and powder X‐ray diffraction. At room temperature the compounds of composition [Mg 2 (H 2 O) 8 ( L )] ( 1 ), [Ca 2 (H 2 O) 6 ( L )] ( 2 ), [Sr 2 (H 2 O) 4 ( L )] ( 3 ) and [Ba 2 (H 2 O) 9 ( L )] ⋅ H 2 O ( 4 ) were discovered. They exhibit the same metal to linker ratio, but differ in their water content. Distinct structural changes are observed with an increase in dimensionality of the coordination polymer with increasing ionic radius of the metal ion. At elevated reaction temperatures the two new metal phosphonates [Mg 2 (H 2 O) 5 ( L )] ( 5 ) and [Ba 2 (H 2 O) 2 ( L )] ⋅ 2 H 2 O ( 6 ) were obtained either from the same reaction mixture as for 1 and 4 , respectively, or by solid state transformation. The detailed characterisation of the all materials is also reported.