Manipulation of Molecular and Supramolecular Structure in Nickel(II) Complexes through the Orientation of Dicarboxylate Hydrogen Bonding Faces

The reactions of the bis(thiosemicarbazide)nickel(II) nitrates [NiL 2 ](NO 3 ) 2 [ 1a, L = tsc, NH 2 C(S)NHNH 2; 1b, L = Metsc, MeNHC(S)NHNH 2; 1c, L = Ettsc, EtNHC(S)NHNH 2; 1d, L = Me 2 tsc, NH 2 C(S)NHNMe 2; and 1e, L = Me 3 tsc, MeNHC(S)NHNMe 2 ] with a range of sodium dicarboxylates led to crystalline products in 19 cases. The reaction with dicarboxylates containing an angle θ of 180° between the carboxylate groups generally led to compounds in which the cations and anions are linked into tapes through hydrogen bonding, and the crystal structures of [Ni(tsc) 2 (OH 2 ) 2 ][fumarate] ( 2 ), [Ni(Me 2 tsc) 2 (OH 2 ) 2 ][fumarate]·H 2 O ( 3 ), [Ni(Me 3 tsc) 2 (OH 2 ) 2 ][fumarate] ( 4 ), and [Ni(tsc) 2 ][4,4‘-biphenyldicarboxylate]·5H 2 O ( 5 ) are reported. A similar tape structure is observed in the crystal structure of [Ni(Me 3 tsc) 2 (OH 2 ) 2 ][isophthalate]·3.2H 2 O ( 6 ) in which the isophthalate anion has an angle θ of 120° between the carboxylate groups. However, such tape structures are not seen with dicarboxylates in which θ is less than 90°, and instead, one of three structural types is observed. These are tris(thiosemicarbazide)nickel(II) dicarboxylates, witnessed by the crystal structures of [Ni(tsc) 3 ][maleate]·H 2 O ( 7 ) and [Ni(Ettsc) 3 ][phthalate]·4H 2 O ( 8 ), neutral compounds containing coordinated dicarboxylates, epitomized by the crystal structures of [Ni(Me 3 tsc) 2 (phthalate)]·2H 2 O ( 9 ), [Ni(Me 2 tsc) 2 (itaconate)]·6H 2 O ( 10 ), and [Ni(Me 3 tsc) 2 (homophthalate)]·4H 2 O ( 11 ) and neutral bis(thiosemicarbazidato)nickel(II) complexes in which the dicarboxylate has acted as a base. Thermogravimetric analyses for the hydrogen-bonded tape structures 2 − 6 and the coordinated dicarboxylate compounds 9 − 11 are reported.