Ni(2,2':6',2″-Terpyridine-4'-carboxylate) 2 Zwitterions and Carboxylate Polyanions in Mixed-Ligand Uranyl Ion Complexes with a Wide Range of Topologies.

The zwitterionic complex formed by Ni II and 2,2':6',2″-terpyridine-4'-carboxylate, Ni(tpyc) 2 , has been used as a coligand with a diverse group of polycarboxylates in uranyl ion complexes synthesized under solvo-hydrothermal conditions, thus giving a series of 14 mixed ligand, heterometallic compounds. Both [(UO 2 ) 2 ( c -1,2-chdc)Ni(tpyc) 2 (NO 3 ) 2 ] 2 ·4CH 3 CN ( 1 ) and [(UO 2 ) 2 (tdc)Ni(tpyc) 2 (NO 3 ) 2 ] 2 ( 2 ), where c -1,2-chdc 2- is cis -1,2-cyclohexanedicarboxylate and tdc 2- is 2,5-thiophenedicarboxylate, display discrete U 4 Ni 2 dinickelatetrauranacycles, a motif which is also found as part of a daisychain coordination polymer in [(UO 2 ) 4 (bdc) 3 Ni 2 (tpyc) 4 (NO 3 ) 2 ]·2CH 3 CN·2H 2 O ( 3 ), where bdc 2- is 1,4-benzenedicarboxylate. Similar U 4 Ni 2 rings associate to form a nanotubular polymer in [(UO 2 ) 2 (tca)Ni(tpyc) 2 (NO 3 )]·2CH 3 CN·2H 2 O ( 4 ), where tca 3- is tricarballylate. [(UO 2 ) 2 (1,2-pda) (1,2-pdaH)Ni(tpyc) 2 (NO 3 )]·CH 3 CN ( 5 ), where 1,2-pda 2- is 1,2-phenylenediacetate, crystallizes as a meander-like chain in which each bent section can be seen as an open, semi-U 4 Ni 2 ring. Oxalate (ox 2- ) gives [(UO 2 ) 2 (ox) 2 Ni(tpyc) 2 ] ( 6 ), a monoperiodic polymer containing smaller U 4 Ni rings, while 1,2,3-benzenetricarboxylate (1,2,3-btc 3- ) and citrate (citH 3- ) give [Ni(tpycH)(H 2 O) 3 ][UO 2 (1,2,3-btc)] 2 ·2H 2 O ( 7 ) and [UO 2 Ni 2 (tpyc) 4 ][UO 2 (citH)] 2 ( 8 ), two complexes with charge separation, the latter displaying one-periodic + two-periodic semi-interpenetration. [(UO 2 ) 2 (btcH)Ni(tpyc) 2 (NO 3 )] ( 9 ) and [(UO 2 ) 2 (cbtcH)Ni(tpyc) 2 (NO 3 )] ( 10 ), where btc 4- and cbtc 4- are 1,2,3,4-butanetetracarboxylate and cis , trans , cis -1,2,3,4-cyclobutanetetracarboxylate, respectively, are diperiodic networks with hcb topology, and [(UO 2 ) 2 (ndc)Ni(tpyc) 2 (OH)(NO 3 )] ( 11 ), where ndc 2- is 2,6-naphthalenedicarboxylate, is a sql network containing dinuclear nodes and involving 100-membered U 10 Ni 4 metallacyclic units. U 4 Ni 2 rings are found in the diperiodic polymer formed in [(UO 2 ) 4 ( t - R -1,2-chdc) 4 Ni 2 (tpyc) 4 ] ( 12 ), where t - R -1,2-chdc 2- is trans - R , R -1,2-cyclohexanedicarboxylate, the heavily puckered sheets being interlocked. 1,3-Phenylenediacetate (1,3-pda 2- ) gives a very thick diperiodic polymer with KIa topology, [(UO 2 ) 4 (1,3-pda) 4 Ni 2 (tpyc) 4 ]·CH 3 CN·2H 2 O ( 13 ). A triperiodic framework is formed with nitrilotriacetate (nta 3- ) in [(UO 2 ) 2 (nta) 2 Ni 2 (tpyc) 2 ] ( 14 ), where Ni II is found in Ni(tpyc) 2 units as well as in Ni(nta) 2 4- moieties which both act as 4-coordinated nodes.