Coordinatively polymeric and monomeric bismuth(iii) complexes with pyridine carboxylic acids

Abstract

Three crystalline compounds, [Bi(2-O(2)C-C(5)H(4)N)(3)](n) (), {Bi[(2,6-O(2)C)(2)C(5)H(3)N)][(2-HO(2)C-6-O(2)C)C(5)H(3)N].H(2)O}(n) (3) and Bi(O(2)CC(9)H(6)N)(2)(O(3)N)(O(2)CC(9)H(6)NH).2H(2)O () have been prepared by simple reactions in aqueous medium using the readily available bismuth nitrate and the corresponding acids, picolinic acid, dipicolinic acid and quinaldic acid. While and are coordination polymers with bismuth in tricapped trigonal prismatic and dodecahedral environments, compound is a monomeric species with dodecahedral geometry at bismuth. Compound represents a second crystalline form of a recently reported structure with subtle differences in bond parameters, and highlights the flexibility in structural motifs during crystallization. Compound involves skeletons with dimeric [Bi(2)O(2)] and trimeric [BiOCOBiOBiOCO] moieties. In , while the N-protonated carboxylate forms a four-membered chelate ring with bismuth, the other two carboxylates form five-membered ring chelates with the nitrate accounting for the remaining two sites again as a chelate. TGA studies are consistent with the presence of non-coordinated water in and . Compounds and , although insoluble in most of the organic solvents and water, are readily soluble in dilute hydrochloric acid.

Studies on bismuth carboxylates—synthesis and characterization of a new structural form of bismuth(III) dipicolinate

“…Bond distances in 5 and 7 are compiled in table 2. As discussed in our previous paper, 6 there are two types of bismuth environments in 5. Also, there are both dimeric [Bi 2 O 2 ] and trimeric [BiOCOBiOBiOCO] moieties in the overall structure.…”

“…6 The crystalline polymorph 4 was prepared by the 0.5:0.5:3 stoichiometric reaction of bismuth nitrate pentahydrate, gadolinium nitrate pentahydrate and picolinic acid; this is a much simpler route for this polymorph than that available in the literature. 7 There was no significant change in the IR spectrum or the melting behaviour between 4 and 4 .…”

“…5 We have embarked on a plan to extend this chemistry in the context of pharmaceutically active bismuth and antimony carboxylates. 6 In this context, we have chosen the biologically compatible picolinic and dipicolinic acids as carboxylic acid sources. In this short paper, we discuss some of our findings on bismuth(III) picolinate and report a new structural form for bismuth bis(dipicolinate).…”

Stabilization of [BiCl6]3− and [Bi2Cl10]4− with various organic precursors as cations leading to inorganic–organic supramolecular adducts: Syntheses, crystal structures and properties of [C5H7N2]3[BiCl6], [C5H7N2][C5H8N2][BiCl6] and [C10H10N2]2[Bi2Cl10]

“…Recently, we have described 1,5-benzodiazepinium cation as a hybrid material component of [Bi 2 Cl 9 ] 3-anion [11]. Even though our original aim was to initiate investigations on bismuth coordination compounds in the relevance of bismuth containing drugs, [11][12][13] the present study led to an significant chemistry leading to the stabilization of [BiCl 6 ] 3-and [Bi 2 Cl 10 ] 4-anions in the title compounds. Herein we report the syntheses, structural characterization and physical properties of compounds [C 5 …”

Three new bismuth(III) pyridine-2,6-dicarboxylate compounds: Synthesis, characterization and crystal structures

“…The bismuth(III) center is highly acidic and can exhibit variable coordination numbers, framework flexibilities, and different structural characteristics [16,18,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51]. Bismuth(III) is known to form stable chelate complexes with pydcH 2 (or its anions) and various crystal structures have been reported [16,17,[45][46][47][48][49][50][51].…”