This work was conducted in order to explore the potential of novel silicon-based Covalent
Organic Frameworks (COFs) and Metal-Organic Frameworks (MOFs) for CO2 capture. A
Lewis acid, cyclo-1,3,3,5,7,7-hexaphenyl-1,5-dibora-3,7-disiloxane (3) was synthesized and
complexed with a variety of Lewis bases such as 4,4ˈbipyridine (L1), 1,2-di(pyridin-4-
yl)ethane (L2), 1,2-di(pyridin-4-yl)ethene (L3), 1,3-di(pyridin-4-yl)propane (L4), 1,2-
di(pyridin-4-yl)sulfane (L5), 1,2-di(pyridin-4-yl)diazene (L6), 1,4-di(pyridin-4-yl)benzene
(L7), 3,5-di(pyridin-3-yl)-1,2,4-thiadiazole (L8) and 3,5-di(pyridin-4-yl)-1,2,4-thiadiazole
(L9) to afford a range of 1-D polymers such as as [Ph6B2Si2O4].L1 (4), [Ph6B2Si2O4].L2 (5),
[Ph6B2Si2O4].L3 0.5(CH2Cl2) (6), [Ph6B2Si2O4].L4 (7), [Ph6B2Si2O4].L5 (8), [Ph6B2Si2O4].2L9.
2[PhB(OH)2] (14) as well as a short polymeric structure [Ph6B2Si2O4].L8 (13). In addition, other
compounds such as Ph8B4Si2O6.L6 (9), 4(C12H12O2Si).3(C10H8N4) (10), Ph4Si2(OH)4.2L7 (11)
and Ph8B4Si2O6.L7 (12) were formed due to ring contraction readiness of compound (3). These
compounds displayed extended inter- and intra-molecular π-π and other forms of π-interactions
as well as hydrogen bonding in their crystal packings. Furthermore, novel silicon-based
tetrakis-, tris- and di- aryl-pyridine linkers such as tetrakis(4-(pyridine-4-vinyl)phenyl)silane
(L10), tri(4-(pyridine-4-vinyl)phenyl)methylsilane (L11), bis(4-(pyridine-4-
vinyl)phenyl)dimethylsilane (L12) tetrakis(4-(pyridine-4-vinyl)biphenyl)silane L13), tri(4-
(pyridine-4-vinyl)biphenyl)methylsilane (L14), as well as aryl-carboxylic acid linkers such as
silane tetrakis(biphenyl-4-carboxylic acid) (L15) and silane tris(biphenyl-4-carboxylic acid)
(L16) have been synthesized from their corresponding aryl-bromine precursors. Treatment of
(L10) with Zn(CH3COO)2 and Zn(NO3)2.6H2O give a 2-D (MOF) (17) and a 3-D MOF (18)
respectively. While (L15) solvothermally formed MOF (19) after treatment with
Zn(NO3)2.6H2O in solvent mixture of H2O/DMA. MOF (17) possesses a pore size of 18.5 Å
iv
with no interpenetration of channels while (18) exhibits a five-fold interpenetration of channels
as well as two types of pores with length and width of 31.42 and 24.62 Å for the big pores
and 15.70 and 12.20 Å for the small pores respectively. MOF (19) exhibits a pore diameter of
17.06 Å.