  Spherosilicate, consisting of a double 4-ring cyclosilicate core (D4R;
Si8O20) with every corner functionalized with a dimethylsilyl chloride group
(-SiMe2Cl), was used as node to construct an iso-reticular series of porous
expanded network materials. Interconnecting the nodes with linear, aliphatic
{\alpha},{\omega}-alkanediol linker molecules yields PolySilicate Porous
Organic Polymers (PSiPOPs), a new type of ordered reticular material related to
the well-known metal-organic and covalent organic frameworks (MOFs & COFs). In
the synthesis, sacrificial hydrogen-bonded Si8O20 cyclosilicate crystals are
first converted into silyl chloride terminated spherosilicate. In a second
step, these nodes are linked up by alkanediol units via the intermediate
formation of a Si-N bond with catalytic amines such as pyridine and
dimethylformamide. Overall, the presented synthesis converts D4R cyclosilicate
into an ordered reticular framework with [Si8O20]-[Si(CH3)2-]8 nodes and
O-(CH2)n-O linkers. Example materials with ethylene glycol, 1,5-pentanediol,
and 1,7-heptanediol as linker (n = 2, 5, and 7) were produced and
characterized. On a macroscopic level, the synthesis yields porous frameworks
exhibiting a thermal stability up to 400{\deg}C and a chemical stability
between pH 1 and 12. N2 physisorption revealed a secondary mesopore structure,
indicating future options to produce hierarchical materials using soft
templates. The molecular level structure of these reticular PSiPOP materials
was elucidated using an NMR crystallography approach implementing a combination
of 1D and 2D 1H and 29Si solid-state MAS NMR spectroscopy experiments.
Previously reported reticular COF/POP materials implementing D4R-based nodes,
used Si8 octakis (phenyl) D4R POSS as a node, connecting it to the linker via a
Si-C bond instead of a Si-O-C linkage.
