Topological aspects of lanthanide–adipate–aqua compounds: Close packed and open framework structures

A searchintheCambridgeStructuralDatabase(CSD)forlanthanidecomplexeswithadipate[OOC(CH2)4 COO]2− and aqualigandsretrievedafairnumberofcompounds.Tothisdatasetanewlanthanummetal– organic framework,{[La2(adip)3(H2O)2] (1) (adipH21⁄4adipic acid),synthesisedandstructurallycharac- terized intheselabs,wasincluded.Thecrystalstructuresofthesecoordinationpolymers,ofgeneral formulation [Ln2(adip)3(H2O)x], exhibitavarietyoftopologiesanddimensionality,whichwereclustered in differentclassesanddescribedindetail.Itwasexploredthatthemajorityoftheseevidencesthe presence ofmetalchainsordinuclear Ln2 entities (separatedinbothcasesby4.0–4.8 Å),where lanthanide ionsaredifferentlyconnectedbycarboxylategroupswithchelatingoroxygen-bridging mode. Thedifferentamountofcoordinatedwatermoleculesappeartoaffectthesolidstatenetworks. Moreoverthecrystalpackingofthesecompoundsshowspeculiaraspectsandexampleswerereportedin the literaturewherethelongalkylchainofadipateconnectorsgiverisetointerpenetratedstructures,or to porousmaterialwherelatticewaterorneutrallargermoleculesareclathrated.