The first supramolecular water–borate–carbonate anionic rosette ribbon sandwiched by a Ag(I) cationic sinusoidal layer

The ultrasonic reaction of Ag2O, 1,3-bis(4-pyridyl)propane (bpp) and Na2B4O5(OH)4·8H2O (borax) under ammoniacal medium gave rise to an unexpected 3D Ag(I) supramolecular sandwich lamellar framework, {[Ag2(bpp)2(H2O)2]·[(H3BO3)3(CO3)·2H2O]}n (1), which consists of 2D silver-bpp cationic host and water–borate–carbonate anionic guest layers. The present 2D anionic layer is formed by fused H2O–H3BO3–CO32 − anionic rosette ribbons, in which H3BO3 is obtained via in situ hydrolysis of borax and CO32 − derived from absorption of CO2 in air. Interestingly, an unprecedented [CO32 −·3(H3BO3)] hydrogen-bonding aggregate having the shape of one concave three-leaved propeller is found in the anionic rosette ribbon.