Stereoselective Synthesis of [5‐[4,4,4,4′,4′,4′‐Hexafluoro‐N‐(2‐hydroxyethoxy)‐D‐valine]]‐ and [5‐[4,4,4,4′,4′,4′‐Hexafluoro‐N‐(2‐hydroxyethoxy)‐L‐valine]cyclosporin A

Addition of various amines to the 3,3‐bis(trifluoromethyl)acrylamides 10a and 10b gave the tripeptides 11a – 11f , mostly as mixtures of epimers (Scheme 3). The crystalline tripeptide 11f ₂ was found to be the N‐terminal (2‐hydroxyethoxy)‐substituted (R,S,S)‐ester HOCH₂CH₂O‐D ‐Val(F₆)‐MeLeu‐Ala‐O^tBu by X‐ray crystallography. The C‐terminal‐protected tripeptide 11f ₂ was condensed with the N‐terminus octapeptide 2b to the depsipeptide 12a which was thermally rearranged to the undecapeptide 13a (Scheme 4). The condensation of the epimeric tripeptide 11f ₁ with the octapeptide 2b gave the undecapeptide 13b directly. The undecapeptides 13a and 13b were fully deprotected and cyclized to the [5‐[4,4,4,4′,4′,4′‐hexafluoro‐N‐(2‐hydroxyethoxy)‐D ‐valine]]‐ and [5‐[4,4,4,4′,4′,4′‐hexafluoro‐N‐(2‐hydroxyethoxy)‐L ‐valine]]cyclosporins 14a and 14b , respectively (Scheme 5). Rate differences observed for the thermal rearrangements of 12a to 13a and of 12b to 13b are discussed.     

Synthesis and antimicrobial activity of N‐substituted N′‐[6‐methyl‐2‐oxido‐1,3,2‐dioxaphosphinino(5,4‐b)pyridine‐2‐yl]ureas

N‐Substituted N′‐[6‐methyl‐2‐oxido‐1,3,2‐dioxaphosphinino(5,4,‐b)pyridine‐2‐yl]ureas have been accomplished by condensation of equimolar quantities of chlorides of various carbamidophosphoric acids ( 3 ) with 3‐hydroxyl‐6‐methyl‐2‐pyridinemethanol (lutidine diol) ( 4 ) in the presence of triethylamine in dry toluene–tetrahydrofuran (1:1) mixture at 45–50°C. Their structures were established by elemental analyses, IR, ¹H NMR, ¹³C NMR, and ³¹P NMR spectral data. Their antifungal and antibacterial activity is also evaluated. Most of these compounds exhibited moderate antimicrobial activity in the assays. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:509–512, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10181     

7‐Halogenated 7‐Deazapurine 2′‐Deoxyribonucleosides Related to 2′‐Deoxyadenosine, 2′‐Deoxyxanthosine,and 2′‐Deoxyisoguanosine: Syntheses and Properties

A series of 7‐fluorinated 7‐deazapurine 2′‐deoxyribonucleosides related to 2′‐deoxyadenosine, 2′‐deoxyxanthosine, and 2′‐deoxyisoguanosine as well as intermediates 4b – 7b, 8, 9b, 10b , and 17b were synthesized. The 7‐fluoro substituent was introduced in 2,6‐dichloro‐7‐deaza‐9H‐purine ( 11a ) with Selectfluor (Scheme 1). Apart from 2,6‐dichloro‐7‐fluoro‐7‐deaza‐9H‐purine ( 11b ), the 7‐chloro compound 11c was formed as by‐product. The mixture 11b / 11c was used for the glycosylation reaction; the separation of the 7‐fluoro from the 7‐chloro compound was performed on the level of the unprotected nucleosides. Other halogen substituents were introduced with N‐halogenosuccinimides ( 11a → 11c – 11e ). Nucleobase‐anion glycosylation afforded the nucleoside intermediates 13a – 13e (Scheme 2). The 7‐fluoro‐ and the 7‐chloro‐7‐deaza‐2′‐deoxyxanthosines, 5b and 5c , respectively, were obtained from the corresponding MeO compounds 17b and 17c , or 18 (Scheme 6). The 2′‐deoxyisoguanosine derivative 4b was prepared from 2‐chloro‐7‐fluoro‐7‐deaza‐2′‐deoxyadenosine 6b via a photochemically induced nucleophilic displacement reaction (Scheme 5). The pK_a values of the halogenated nucleosides were determined (Table 3). ¹³C‐NMR Chemical‐shift dependencies of C(7), C(5), and C(8) were related to the electronegativity of the 7‐halogen substituents (Fig. 3). In aqueous solution, 7‐halogenated 2′‐deoxyribonucleosides show an approximately 70% S population (Fig. 2 and Table 1).     

Electrocrystallization of Tetra‐ and Hexa‐coordinated Silver(II) Compounds Based on 4,4′‐Dimethyl‐2,2′‐Bipyridine Ligand – Single Crystal Structures and Magnetic Studies

In this paper we report on the potential dependent electrocrystallization of [Ag(4,4′‐dimethyl‐2,2′‐bipyridine)₂(NO₃)₂] ( 1 ) and Ag(4,4′‐dimethyl‐2,2′‐bipyridine)(NO₃)₂ ( 2 ) from the same electrolytic bath. Thus it has been shown for the first time that the coordination number of silver ion to ligands can be tuned by the electrocrystallization potential. The single crystal structure analysis [ 1 : C2/c, a = 18.6308(15), b = 14.5708(12), c = 11.5867(10) Å, β = 126.5910(10)°, Z = 4, R = 3.9 %] [ 2 : P2₁/c, a = 8.5865(11) b = 11.0157(14) c = 16.4554(10) Å, β = 111.102(10), Z = 4 , R = 3.5 %] show divalent silver to be in an approximately square planar surrounding. Both complexes are paramagnetic following Curie's law with magnetic moments of 1.86 μ_B and 1.72 μ_B respectively.     

catena‐Poly­[[di‐μ‐benzoato‐κ4O:O′‐disilver(I)]‐μ‐N,N′‐bis(2‐fluoro­benzyl­idene)­butane‐1,4‐di­amine‐κ2N:N′]

The title complex, [Ag₂(C₇H₅O₂)₂(C₁₈H₁₈F₂N₂)]_n, is a dinuclear silver(I) compound with one inversion centre between pairs of Ag atoms and another at the mid‐point of the central C—C bond in the butane‐1,4‐diamine moiety. Each of the smallest repeat units consists of two silver(I) cations, two benzoate anions and one N,N′‐bis(2‐fluorobenzyl­idene)­butane‐1,4‐di­amine Schiff base ligand. Each Ag^I ion is three‐coordinated in a trigonal configuration by two O atoms from two benzoate anions and one N atom from a Schiff base ligand. The di‐μ‐benzoato‐disilver(I) moieties are linked by the bridging Schiff base ligand, giving zigzag polymeric chains with an [–Ag⋯Ag—N—C—C—C—C—N–]_n backbone running along the b axis.     

2,2,2‐triaryl‐4‐oxo‐1,3,2‐benzoxazastibinines

The hitherto unreported 4‐oxo‐1,3,2‐benzoxazastibinines 2 have been synthesized by the cyclization of disodium salt of salicylanilide ( 1 ) with Ar₃SbBr₂ (Ar = Ph, p‐tolyl, or mesityl). These compounds have been characterized by elemental analyses, molecular weight determination, and by IR, far IR, ¹H, and ¹³C NMR spectral studies. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:622–624, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10202     

Synthesis of 3′‐1,2,4‐triazolo‐ and 3′‐1,3,4‐thiadiazoliminothymidines

New 5′‐acetyl‐3′‐1,3,4‐thiadiazoliminothymidines 11, 14 were prepared, via spontaneous rearrangments, by cycloaddition of 5′‐acetyl‐3′‐deoxy‐3′‐isothiocyanatothymidine 9 with 1‐aza‐2‐azoniaallene hexachloantimonates. Similary, 3′‐cyano analogue 19 was reacted with the same cumulenes to furnish 3′‐1,2,4‐triazolo‐thymidines 22, 24 , and 26 . Deblocking of the acylated products afforded the free nucleosides. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:298–303, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10146     

Flip‐type disorder in 3‐substituted 2,2′:5′,2′′‐terthiophenes

In the crystal structures of four thiophene derivatives, (E)‐3′‐[2‐(anthracen‐9‐yl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₈H₁₈S₃, (E)‐3′‐[2‐(1‐pyrenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₃₀H₁₈S₃, (E)‐3′‐[2‐(3,4‐dimethoxyphenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₂H₁₈O₂S₃, and (E,E)‐1,4‐bis[2‐(2,2′:5′,2′′‐terthiophen‐3′‐yl)ethenyl]‐2,5‐dimethoxybenzene, C₃₆H₂₆O₂S₆, at least one of the terminal thiophene rings is disordered and the disorder is of the flip type. The terthiophene fragments are far from being coplanar, contrary to terthiophene itself. The central C—C=C—C fragments are almost planar but the bond lengths suggest slight delocalization within this fragment. The crystal packing is determined by van der Waals interactions and some weak, relatively short, C—H...S and C—H...π directional contacts.     

Synthesis of (5′S)‐5′‐C‐Alkyl‐2′‐deoxynucleosides

We describe the synthesis of (5′S)‐5′‐C‐butylthymidine ( 5a ), of the (5′S)‐5′‐C‐butyl‐ and the (5′S)‐5′‐C‐isopentyl derivatives 16a and 16b of 2′‐deoxy‐5‐methylcytidine, as well as of the corresponding cyanoethyl phosphoramidites 9a , b and 14a , b , respectively. Starting from thymidin‐5′‐al 1 , the alkyl chain at C(5′) is introduced via Wittig chemistry to selectively yield the (Z)‐olefin derivatives 3a and 3b (Scheme 2). The secondary OH function at C(5′) is then introduced by epoxidation followed by regioselective reduction of the epoxy derivatives 4a and 4b with diisobutylaluminium hydride. In the latter step, a kinetic resolution of the diastereoisomer mixture 4a and 4b occurs, yielding the alkylated nucleoside 2a and 2b , respectively, with (5′S)‐configuration in high diastereoisomer purity (de=94%). The corresponding 2′‐deoxy‐5‐methylcytidine derivatives are obtained from the protected 5′‐alkylated thymidine derivatives 7a and 7b via known base interconversion processes in excellent yields (Scheme 3). Application of the same strategy to the purine nucleoside 2′‐deoxyadenine to obtain 5′‐C‐butyl‐2′‐deoxyadenosine 25 proved to be difficult due to the sensitivity of the purine base to hydride‐based reducing agents (Scheme 4).     

Synthesis and tuberculostatic activity of novel N′‐methyl‐4‐(pyrrolidin‐1‐yl)picolinohydrazide and N′‐methylpyrimidine‐2‐carbohydrazide derivatives

The synthesis of N′‐methyl‐4‐(pyrrolidin‐1‐yl)picolinohydrazide and N′‐methyl‐pyrimidine‐2‐carbohydrazide derivatives ( 5a and 5b ) was carried out. These compounds were used as starting materials to obtain methyl N′‐methylhydrazinecarbodithioates 6a and 6b , which, on reaction with either triethylamine or hydrazine, gave corresponding 1,3,4‐oxadiazioles 7a and 7b or 1,2,4‐triazoles 9a and 9b with the free NH₂ group at the N‐4 position, respectively. Compounds 8a – e , particularly containing cyclic amines at N‐4 of the 1,2,4‐triazole ring, were also obtained. Synthesized compounds were tested in vitro for their activity against Mycobacterium tuberculosis. The structure–activity relationship analysis for obtained compounds was done. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:223–230, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21008     

New 3,3′[2,2′‐oxy‐bis‐(oxazaborolidine)]‐ethylenes. Structural studies by NMR,X‐ray,and quantum chemistry methods

3,3′‐[2,2′‐Oxy‐bis‐(4S‐methyl, 5R‐phenyl‐1,3,2‐oxazaborolidine)]ethylene ( 4a ) and 3,3′‐[2, 2′‐oxy‐(4S‐methyl‐5R‐phenyl‐1,3,2‐oxazaborolidine)‐ (1,3,2‐benzoxazaborolidine)]ethylene ( 4b ) were synthesized by the reaction of N,N′‐bis‐[(1R,2S)‐norephedrine]oxalyl ( 3a ) or N,N′‐[((1R,2S)‐norephedrine, o‐hydroxyphenylamine]oxalyl ( 3b ) with BH₃‐THF. The molecular structure of these compounds was established by NMR and infrared spectroscopy. The molecular geometry for 4 was studied by means of theoretical methods, resulting in structures that were in total agreement with those obtained by spectroscopy data and X‐ray diffraction. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:513–519, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20151     

Syntheses and crystal structures of triorganotin (IV) derivatives with 2,2′‐bipyridine‐4,4′‐dicarboxylic acid

Four organotin complexes with 2,2′‐bipyridine‐4,4′‐dicarboxylic acid, H₂dcbp: (Ph₃n)₂(dcbp) 1 , [(PhCH₂)₃n]₂(dcbp) ⋅ 2CH₃OH 2 , [(Me₃Sn)₂(dcbp)]_n 3 , [(Bu₃Sn)₂(dcbp)]_n 4 have been synthesized. The complexes 1–4 were characterized by elemental, IR, ¹H, ¹³C, ¹¹⁹n NMR, and X‐ray crystallographic analyses. Crystal structures show that complex 1 is a monomer with one ligand coordinated to two triorganotin moieties, and a 1D infinite polymeric chain generates via intermolecular C H⋅⋅⋅N hydrogen bond; complex 2 is also a monomer and forms a 2D network by intermolecular O–H⋅⋅⋅O weak interaction; both of complexes 3 and 4 form 2D network structures where 2,2′‐bipyridine‐4,4′‐dicarboxylate acts as a tetradentate ligand coordinated to trimethyltin and tri‐n‐butyltin ions, respectively. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:19–28, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20506     

3,3′‐Dinitro‐2,2′‐dithiodipyridine

In the title compound, C₁₀H₆N₄O₄S₂, (I), the molecule has a centre of inversion. The structure is a positional isomer of 5,5′‐dinitro‐2,2′‐dithiodipyridine [Brito, Mundaca, Cárdenas, López‐Rodríguez & Vargas (2007). Acta Cryst. E 63 , o3351–o3352], (II). The 3‐nitropyridine fragment of (I) shows excellent agreement with the bonding geometries of (II). The most obvious differences between them are in the S—S bond length [2.1167 (12) Å in (I) and 2.0719 (11) Å in (II)], and in the C—C_ipso—N_ring [119.8 (2)° in (I) and 123.9 (3)° in (II)] and S—C—C [122.62 (18)° in (I) and 116.0 (2)° in (II)] angles. The crystal structure of (I) has an intramolecular C—H...O interaction, with an H...O distance of 2.40 (3) Å, whereas this kind of interaction is not evident in (II). The molecules of (I) are linked into centrosymmetric R⁴₄(30) motifs by a C—H...O interaction. There are no aromatic π–π stacking and no C—H...π(arene) interactions. Compound (I) can be used as a nucleophilic tecton in self‐assembly reactions with metal centres of varying lability.     

Synthesen und Strukturen von Bis(4,4′‐t‐butyl‐2,2′‐bipyridin)‐Ruthenium(II)‐Komplexen mit funktionellen Derivaten des Tetramethyl‐bibenzimidazols

Syntheses and Structures of Bis(4,4′‐t‐butyl‐2,2′‐bipyridine) Ruthenium(II) Complexes with functional Derivatives of Tetramethyl‐bibenzimidazole [(tbbpy)₂RuCl₂] reacts with dinitro‐tetramethylbibenzimidazole ( A ) in DMF to form the complex [(tbbpy)₂Ru( A )](PF₆)₂ ( 1a ) (tbbpy: bis(4,4′‐t‐butyl)‐2,2′bipyridine). Exchange of the two PF₆^? anions by a mixture of tetrafluor‐terephthalat/tetrafluor‐terephthalic acid results in the formation of 1b in which an extended hydrogen‐bonded network is formed. According to the ¹H NMR spectra and X‐ray analyses of both 1a and 1b , the two nitro groups of the bibenzimidazole ligand are situated at the periphery of the complex in cis position to each other. Reduction of the nitro groups in 1a with SnCl₂/HCl results in the corresponding diamino complex 2 which is a useful starting product for further functionalization reactions. Substitution of the two amino groups in 2 by bromide or iodide via Sandmeyer reaction results in the crystalline complexes [(tbbpy)₂Ru( C )](PF₆)₂ and [(tbbpy)₂Ru( D )](PF₆)₂ ( C : dibromo‐tetrabibenzimidazole, D : diiodo‐tetrabibenzimidazole). Furthermore, 2 readily reacts with 4‐t‐butyl‐salicylaldehyde or pyridine‐2‐carbaldehyde under formation of the corresponding Schiff base Ru^II complexes 5 and 6 . ¹H NMR spectra show that the substituents (NH₂, Br, I, azomethines) in 2 ‐ 6 are also situated in peripheral positions, cis to each other. The solid state structure of both 2 , and 3 , determined by X‐ray analyses confirm this structure. In addition, the X‐ray diffraction analyses of single crystals of the complexes [(tri‐t‐butyl‐terpy)(Cl)Ru( A )] ( 7 ) and [( A )PtCl₂] ( 8 ) display also that the nitro groups in these complexes are in a cis‐arrangement.     

2,2′‐Anhydro‐1‐(3′,5′‐di‐O‐acetyl‐β‐D‐arabinofuranosyl)uracil,a cyclouridine nucleoside with a C4′‐endo furanosyl conformation

2,2′‐Anhydro‐1‐(3′,5′‐di‐O‐acetyl‐β‐D‐arabinofuranosyl)uracil, C₁₃H₁₄N₂O₇, was obtained by refluxing 2′,3′‐O‐(methoxymethylene)uridine in acetic anhydride. The structure exhibits a nearly perfect C4′‐endo (⁴E) conformation. The best four‐atom plane of the five‐membered furanose ring is O—C—C—C, involving the C atoms of the fused five‐membered oxazolidine ring, and the torsion angle is only −0.4 (2)°. The oxazolidine ring is essentially coplanar with the six‐membered uracil ring [r.m.s. deviation = 0.012 (5) Å and dihedral angle = −3.2 (3)°]. The conformation at the exocyclic C—C bond is gauche–trans which is stabilized by various C—H...π and C—O...π interactions.     

Synthesis and photophysical properties of 2,5,8,11‐tetrakis(5‐hexylthiophen‐2‐yl)tetrathieno[2,3‐a:3′,2′‐c:2′′,3′′‐f:3′′′,2′′′‐h]naphthalene

The title compound, C₅₈H₆₄S₈, has been prepared by Pd‐catalysed direct C—H arylation of tetrathienonaphthalene (TTN) with 5‐hexyl‐2‐iodothiophene and recrystallized by slow evaporation from dichloromethane. The crystal structure shows a completely planar geometry of the TTN core, crystallizing in the monoclinic space group P2₁/c. The structure consists of slipped π‐stacks and the interfacial distance between the mean planes of the TTN cores is 3.456 (5) Å, which is slightly larger than that of the comparable derivative of tetrathienoanthracene (TTA) with 2‐hexylthiophene groups. The packing in the two structures is greatly influenced by both the aromatic core of the structure and the alkyl side chains.     

Crystallographic report: A three‐dimensional coordination polymer: [Zn6(btc)4(4,4′‐bipy)5]n (btc = 1,2,4‐benzenetricarboxylate; 4,4′‐bipy = 4,4′‐bipyridine)

The three‐dimensional (3D) coordination polymer [Zn₆(btc)₄(4,4′‐bipy)₅]_n ( 1 ) (btc = 1,2,4‐benzenetricarboxylate; 4,4′‐bipy = 4,4′‐bipyridine) has been prepared hydrothermally. The zinc(II) centers in 1 are bridged by btc ligands to form a trinuclear subunit, which is further linked by 4,4′‐bipy and btc ligands to construct the 3D coordination architecture. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis of 3‐substituted pyrido[4′,3′:4,5]thieno[2,3‐d]pyrimidines and related fused thiazolo derivatives

Convenient syntheses of 3‐substituted ethyl 4‐oxo‐2‐thioxo‐1,2,3,4,5,6,7,8‐octahydropyrid[4′,3′:4,5]thieno[2,3‐d]pyrimidine‐7‐carboxylates 3a, b, 6, 11–13 , ethyl 3‐methyl‐5‐oxo‐2,3,6,9‐tetrahydro‐5 H‐pyrido[4′,3′:4,5]thieno[2,3‐d][1,3]thiazolo[3,2‐a]pyrimidine‐8‐7H‐carboxylate ( 4 ), and ethyl 2‐methyl‐5‐oxo‐2,3,6,9‐tetrahydro‐5H‐pyrido[4′,3′:4,5]thieno[2, 3‐d][1,3]thiazolo[3,2‐a]pyrimidine‐8[7H]carboxylate ( 8 ) from diethyl 2‐isothiocyanato‐4,5,6,7‐tetrahythieno[2,3‐c]pyridine‐3,6‐dicarboxylate ( 1 ) are reported. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:201–207, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10131     

7‐Deaza‐2′‐deoxy­guanosine

In the title compound, 2‐amino‐7‐(2‐deoxy‐β‐d ‐erythro‐pentofuran­osyl)‐3,7‐dihydro­pyrrolo[2,3‐d]pyrimidin‐4‐one, C₁₁H₁₄N₄O₄, the N‐glycosylic bond torsion angle, χ, is anti [−106.5 (3)°]. The 2′‐deoxy­ribofuran­osyl moiety adopts the ³T₄ (N‐type) conformation, with P = 39.1° and τ_m = 40.3°. The conformation around the exocyclic C—C bond is ap (trans), with a torsion angle, γ, of −173.8 (3)°. The nucleoside forms a hydrogen‐bonded network, leading to a close‐packed multiple‐layer structure with a head‐to‐head arrangement of the bases. The nucleobase interplanar O=C—C⋯NH₂ distance is 3.441 (1) Å.     

Crystal‐to‐crystal transformation upon dehydration of a copper(II) 2,2′:6′,2′′‐terpyridine complex

The reaction of 2,2′:6′,2′′‐terpyridine (terpy) with CuCl₂ in the presence of sodium sulfite led to the synthesis of the ionic complex aquachlorido(2,2′:6′,2′′‐terpyridyl‐κ³N,N′,N′′)copper(II) chlorido(dithionato‐κO)(2,2′:6′,2′′‐terpyridyl‐κ³N,N′,N′′)cuprate(II) dihydrate, [CuCl(C₁₅H₁₁N₃)(H₂O)][CuCl(S₂O₆)(C₁₅H₁₁N₃)]·2H₂O, (I), and the in situ synthesis of the S₂O₆²⁻ dianion. Compound (I) is composed of a [CuCl(terpy)(H₂O)]⁺ cation, a [Cu(S₂O₆)(terpy)]⁻ anion and two solvent water molecules. Thermogravimetric analysis indicated the loss of two water molecules at ca 363 K, and at 433 K the weight loss indicated a total loss of 2.5 water molecules. The crystal structure analysis of the resulting pale‐green dried crystals, μ‐dithionato‐κ²O:O′‐bis[chlorido(2,2′:6′,2′′‐terpyridyl‐κ³N,N′,N′′)copper(II)] monohydrate, [Cu₂Cl₂(S₂O₆)(C₁₅H₁₁N₃)₂]·H₂O, (II), revealed a net loss of 1.5 water molecules and the formation of a binuclear complex with two [CuCl(terpy)]⁺ cations bridged by a dithionate dianion. The crystal‐to‐crystal transformation involved an effective reduction in the unit‐cell volume of ca 7.6%. In (I), the ions are linked by O—H...O hydrogen bonds involving the coordinated and solvent water molecules and O atoms of the dithionate unit, to form ribbon‐like polymer chains propagating in [100]. These chains are linked by Cu...Cl interactions [3.2626 (7) Å in the cation and 3.3492 (7) Å in the anion] centred about inversion centres, to form two‐dimensional networks lying in and parallel to (01). In (II), symmetry‐related molecules are linked by O—H...O hydrogen bonds involving the partially occupied disordered water molecule and an O atom of the bridging thiosulfite anion, to form ribbon‐like polymer chains propagating in [100]. These chains are also linked by Cu...Cl interactions [3.3765 (12) Å] centred about inversion centres to form similar two‐dimensional networks to (I) lying in and parallel to (02), crosslinked into three dimensions by C—H...O=S and C—H...O(water) interactions.