Synthesis,Characterization and Crystal Structure of the Bis(2,4-dinitrobenzoato)tetrabutyldistannoxane(IV) Dimer

Abstract The title compound, bis(2,4-dinitrobenzoato)tetrabutyldistannoxane(IV), was obtained from the reaction of di-n-butyltin(IV) oxide with 2,4-dinitrobenzoic acid. It crystallizes out as the usual dicarboxylatotetrabutyldistannoxane(IV) dimer. In the monoclinic system P2₁/c, a = 12.391(3) ?, b = 19.937(5) ?, c = 15.026(4) ?, α = γ = 90°, β = 102.857(2)°, V = 3618.95(16) ?³ and Z = 2. A crystal structure determination of the title compound reveals the presence of a centrosymmetric planar Sn₂O₂, with two different environments for tin atoms and two distinct carboxylate groups. Two of the carboxylate groups are bonded to the exocyclic tin atom in a bidentate bridging manner and the remaining two carboxylate groups are bonded to the tin atom in a monodentate manner. As a result, both the tin atoms moieties in the complex are five coordinate and exhibit trigonal bipyramid geometry. Index Abstract Synthesis, Characterization and Crystal Structure of the Bis(2,4-dinitrobenzoato)tetrabutyldistannoxane(IV) Dimer Yip Foo Win, Teoh Siang Guan, Lim Eng Khoon, Shea Lin Ng, Hoong Kun Fun A crystal structure determination of the title compound reveals the presence of a centrosymmetric planar Sn₂O₂, with two different environments for tin atoms and two distinct carboxylate groups.      

Copper(II)-pyrazine-2,3-dicarboxylate Coordination Polymer with Monoethanolamine, [Cu(μ<Subscript>3</Subscript>-pzdc)(mea)]<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>

Abstract  

A novel Cu(II)-pyrazine-2,3-dicarboxylate complex with monoethanolamine ligand (mea), [Cu(μ₃-pzdc)(mea)]_n (1), has been synthesized and characterized by elemental, spectral (IR and UV–Vis.) and thermal analyses. The molecular structure of polynuclear complex has been determined by the single crystal X-ray diffraction technique. The pyrazine-2,3-dicarboxylate dianion exhibits tetradentate-μ₃ bridging ligand through three carboxylate oxygens and one nitrogen atom. The complex contains two copper(II) ions that exhibit two different coordination environments with two mea, two pzdc ligands, respectively. The Cu1(II) ion is coordinated by two carboxylate oxygen atoms, two N atoms and two O atoms of symmetry related carboxylate group, forming a distorted octahedral geometry, while Cu2(II) ion is coordinated by two bidentate mea ligands and remaining two coordination sites of distorted octahedral geometry are occupied by two carboxylate oxygen atoms of neighboring Cu1 molecule. Thermal analysis property and thermal decomposition mechanism of complex have been investigated by using thermal analyses techniques (TG, DTG and DTA).     

Monomeric and Dimeric Erbium(III) Complexes: Crystal Structure and Photoluminescence Studies

Abstract  

The crystal structure and photoluminescence (PL) studies of the monomeric and dimeric Er(III) complexes with two different chelating ligands (anthracene-9-carboxylic acid, 9-ACA; pentaethylene glycol, EO5; and picric acid, HPic) are reviewed. The Er(III) metal ion was coordinated to the attached ligands in eight- and nine-coordination number. The dimeric [Er₂(9-AC)₆(DMF)₂(H₂O)₂] complex shows the presence of deprotonated 9-AC anions with the negatively charged oxygen atoms bridged two Er(III) ions leads to a great coordinative flexibility via three possibilities of coordination modes, i.e. monodentate, chelation bidentate, chelating–bridging tridentate, where 9-AC = anthracene-9-carboxylate anion. The monomeric [Er(Pic)₂(EO5)](Pic) complex displays the important flexible structure of the acyclic EO5 ligand and the role of Pic anions act as bidentate and monodentate chelations. The PL spectra of both Er(III) complexes show a broad band with the center peak position being dependent on the attached aromatic ligands. The heavier lanthanide complexes show the difference in structures, coordination geometry environment, and luminescence properties compared to the lighter lanthanide complexes. The energy transfer process in the complexes could be optimized with maximize the overlap between the emission spectrum of donor atom and absorption spectrum of acceptor atom.     

Crystal Structures of Two Aromatic Zinc(II) Carboxylates: [Zn(4-Chlorosalicylato)2(H2O)4]·2theophylline·(H2O)2 and Unique [Zn(5-Chlorosalicylato)2(isonicotinamide)2(H2O)]

Abstract  

The crystal structures of two zinc(II) 4-chloro- and 5-chlorosalicylate complexes, [Zn(4-ClC₆H₃-2-(OH)COO)₂(H₂O)₄]·2tph·(H₂O)₂ (I) and [Zn(5-ClC₆H₃-2-(OH)COO)₂(ina)₂(H₂O)] (II), where tph is theophylline and ina is isonicotinamide, have been determined using X-ray diffraction methods. Crystals of both (I) and (II) are triclinic, space group P-1, with Z = 1 in a cell with a = 7.2220(3), b = 8.59700(10), c = 16.0210(5) ?, α = 75.990(2), β = 83.959(2), γ = 68.455(2)°, V = 897.54(5) ?³ (I) and with Z = 2 in a cell with a = 11.4148(11), b = 11.5327(10), c = 12.0685(13) ?, α = 63.458(6), β = 87.547(8), γ = 89.387(7)°, V = 1419.9(2) ?³ (II). The coordination environment of the zinc(II) atom of compound (I) consists of two unidentate carboxylate oxygen atoms and four oxygen atoms of aqua ligands, forming a distorted octahedral configuration. Two theophylline molecules and the remaining water molecules are bound only by hydrogen bonds. The Zn atom of compound (II) is pentacoordinated with two unidentate carboxylate oxygen atoms, two pyridine nitrogen atoms of isonicotinamide ligands, and the oxygen atom of the aqua ligand, forming a distorted configuration between square pyramid and trigonal bipyramid. In both complexes intramolecular O–H···O hydrogen-bonding interactions are present. In the crystal structures, molecules are linked by intermolecular O–H···O and N–H···O hydrogen bonds. The structures are analyzed and compared to the similar Zn(II) complexes, with the chromophores ZnO₆ and ZnO₃N₂.     

The Crystal Structure and Cytotoxicity of Centrosymmetric Copper(II) Complex Derived from S-methyldithiocarbazate with Isatin

Abstract  

Copper(II) complex of S-methyldithiocarbazate with isatin has been prepared and screened for their cytotoxic activities against MCF-7 (Human non-metastatic mammary gland adenocarcinoma cell line) and MDA-MB-231 (Human metastatic mammary gland adenocarcinoma cell line). The compound crystallized in an orthorhombic crystal system with a space group C 2cb and was found to be selectively active against MCF-7 cell line (Human non-metastatic mammary gland adenocarcinoma cell line with an IC₅₀ value 0.45 μg/mL. The crystal structure of this centrosymmetric Cu(SMISA)₂ complex (SMISA = Schiff base formed by condensation reaction of S-methyldithiocarbazate with isatin) showed that the copper atom has a distorted square-planar geometry with the Schiff base coordinated to the metal ion as a uninegatively charged bidentate ligand through the azomethine nitrogen and thiolate sulfur.     

Two Novel Crystal Structures of 2-Mercapto-1,3,4-thiadiazole Complexes with Mercury (II) Chloride

Abstract  

Two novel complexes 1 and 2 have been simultaneously obtained by the reaction of 2-mercapto-1,3,4-thiadiazole (MTD) with mercury (II) chloride (HgCl₂) in CH₃CN, and their crystal structures are characterized by single-crystal X-ray diffraction analysis. Crystal structures show that each Hg(II) of 1 is four coordinated with two chloride anions and two exocyclic sulfur atoms of two adjacent MTDs, and each Hg(II) of 2 is three coordinated with one chloride anion, one nitrogen atom and one exocyclic sulfur atom of two adjacent MTDs, respectively. Assisting the intermolecular works such as S···S, S···Cl or Hg···S interactions, both two complexes 1 and 2 are formed 2D supramolecular architectures. The results obtained conform the MTD can exist thiol and thione forms in the solid state.     

Synthesis,Crystal Structure and IR Spectra of Complexes of Mn(II) by Indole-2-Carboxylic or Isoquinoline-1-Carboxylic Acids and 1,10-Phenanthroline

Abstract  

Two ternary complexes of manganese(II) indole-2-carboxylate (2-IC⁻) or isoquinolinecarboxylate (IQC⁻) with 1,10-phenanthroline (phen) in methanol or in dimethylacetamide (DMA) were synthesized and studied by X-ray diffraction and IR spectra. [Mn(C₉H₆NO₂)₂(C₁₂H₈N₂)₂]·CH₄O (1) crystallizes in the triclinic space group P-1 with cell parameters of a = 10.548(2) ?, b = 14.168(3) ?, c = 14.580(3) ?, α = 62.35(2)°, β = 69.16(2)°, γ = 78.61(2)°, V = 1802.4(6) ?³ and Z = 2; [Mn(C₁₀H₆NO₂)₂(C₁₂H₈N₂)].C₄H₉NO (2) crystallizes in the monoclinic space group P2₁/a with cell parameters of a = 15.304(5) ?, b = 12.871(5) ?, c = 17.421(5) ?, β = 114.39(1), V = 3125(2) ?³ and Z = 4. In 1, Mn is six-coordinate by two bidentate phen ligands and two 2-IC⁻ ligands and exhibits a very distorted octahedral geometry. This complex is solvated by methanol involved in hydrogen bonding. In 2, Mn atom is surrounded by one bidentate phen ligand and two bidentate IQC⁻ ligands. The complex exhibits a distorted octahedral geometry around the Mn^II atom. The crystal structure is completed by a disordered DMA solvate molecule. The IR spectra of both compounds are slightly different in the range 4000–2400 cm⁻¹ which may be attributed to hydrogen bond lack in 2.     

Crystal structures of three methylmercury(II) complexes with thiazolidine-2-thione

The crystal structures of three CH₃Hg⁺ complexes with 1,3-thiazolidine-2-thione (HT) are reported. The cationic [(CH₃Hg)HT]NO₃ complex is monoclinic, space group P2₁/c,a=7.158(14),b=10.156(7),c=13.472(12) Å,=108.21(4)°,Z=4. The structure was refined toR=0.045. The [(CH₃Hg)HT]⁺ cation contains a CH₃Hg⁺ group bonded to the exocyclic S atom of the ligand retaining its N-H proton. This proton is lost and the CH₃Hg⁺ group remains bonded to sulfur in the neutral [(CH₃Hg)T] compound (hexagonal, P6₃,a=13.502(8),c=6.984(7) Å,Z=6,R=0.027). The [(CH₃Hg)₂T]NO₃ compound (monoclinic, C2/c,a=25.200(10),b=7.029(6),c=17.946(8),=128.99(3)°,Z=8,R=0.047) contains complex cations in which the CH3Hg⁺ groups are bonded to N and the exocyclic S atom. This series of compounds shows that the exocyclic S atom is always the first target for the CH₃Hg⁺ group, which is also found to bind to nitrogen in the 2:1 compound. No coordination is observed with the endocyclic S site, which does not even participate in intermolecular H-bonding or HgS contacts in the solids.     

A Sodium Supported Borate Ester: Synthesis,Spectral Characterization and Crystal Structure of dimeric Sodium Organoborate Complex [Na(py)][B(hyncaH<Subscript>−2</Subscript>)<Subscript>2</Subscript>]<Subscript>2</Subscript>

Abstract  A dimeric sodium supported borate complex, [Na(py)][B(hyncaH₋₂)₂]₂ (1) (py = pyridine, hynca = 1-hydroxynaphthalene-2-carboxylic acid), has been synthesised by the reaction of NaBH₄ with two equivalents of hynca in anhydrous THF and following crystallization from py/H₂O solution afforded borate ester derivative. The complex has been fully characterized by FT-IR in the solid state and by NMR (¹H and ¹³C) spectroscopy and electrospray ionization mass spectrometry in solution. The molecular structure of the title compound was determined by single crystal X-ray diffraction. Structure analysis of complex 1 confirmed the presence of an anionic complex [B(hyncaH₋₂)₂]⁻ in which boron atom is coordinated simultaneously by two hynca ligands utilising both alkoxide and carboxylate groups for bonding. The Na atom is six- coordinate to five O atoms of hydroxy carboxylic acid and one pyridine N atom. Crystal data: crystal system, monoclinic, a = 10.971(3) Å, b = 6.839(3) Å, c = 30.545(5) Å, β = 92.20(2)°, space group P2₁/c (#14), V = 2,290(1) Å³, Z = 4. Index Abstract  There are limited examples of alkali metal supported borate ester complexes.      

Synthesis and Crystal Structure of One Trinuclear di-<Emphasis Type="Italic">n</Emphasis>-butyltin(IV) Complex with Salicylaldoxime

Abstract   One trinuclear di-n-butyltin(IV) complex with salicylaldoxime (o-HON=CHC₆H₄OH=HONZOH), (Bu₂Sn)(Bu₂SnO)(Bu₂SnOH)(ONZOH)(ONZO), has been synthesized and characterized by elemental analyses, IR spectrum, and single crystal X-ray diffraction. This complex is a small cluster displaying two unequivalent salicylaldoximate with one seven-coordinate pentagonal–bipyramidal tin atom linked two five-coordinate trigonal–bipyramidal tin atoms via a network of oxygen atoms by Sn–O–Sn bridges. The hydrogen bonds (o-HON=CHC₆H₄–O…H–O) are observed in the complex. These hydrogen bonds include intramolecular hydrogen bonds and intermolecular hydrogen bonds. (Bu₂Sn)(Bu₂SnO)(Bu₂SnOH)(ONZOH)(ONZO) belongs to monoclinic: space group P2₁/n, with a = 12.2307(15) ?, b = 17.361(2) ?, c = 20.976(3) ?, β = 94.424(2)°, V = 4440.5(10) ?³, Z = 4, D _c  = 1.500 g/cm³, μ(MoKα) = 1.715 mm⁻¹, F(000) = 2024, and final R ₁ = 0.0426, wR ₂ = 0.1064 for observed reflections 7779(I > 2σ(I)). Index abstract  The title compound, di-n-butyltin(IV) complex with salicylaldoxime, was synthesized and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that the molecular structure of the title compound is trinuclear. The complex is a small cluster displaying two unequivalent salicylaldoximate with one seven-coordinate pentagonal–bipyramidal tin atom linked two five-coordinate trigonal–bipyramidal tin atoms via a network of oxygen atoms by Sn–O–Sn bridges.      

Synthesis and Crystal Structure of a Carboxylate Bridged Binuclear Copper Complex of Schiff Base Derived from β-amino acid and Salicylaldehyde

Abstract  

The tridentate ligand H₂L (H₂L = β-phenylalanine, N-[1-(2-hydroxyphenyl)propylidene] reacts with copper(II) nitrate and imidazole to give binuclear compound [Cu₂L₂(imi)₂] (1). The coordination geometry of each copper(II) ion is best described as a square-pyramided with one nitrogen atom, two oxygen atoms of the ligand one nitrogen atom of imidazole and one carboxylate oxygen atom belong to another ligand. It crystallizes in the monoclinic system P−1 with a = 7.8439(12) ?, b = 10.2717(16) ?, c = 11.6885(18) ?, α = 76.672(2)°, β = 85.397(2)°, γ = 71.412(2)°, V = 868.6(2) ?³, Z = 1.     

Synthesis and Crystal Structures of the Five-Coordinate Diorganotin(IV) Complex [Ph<Subscript>2</Subscript>Sn(L)]·DMF and its 5-Hydroxypyrazoline Ligand (H<Subscript>2</Subscript>L)

Abstract  

A five-coordinate diorganotin(IV) complex [Ph₂Sn(L)]·DMF and its ligand, 5-hydroxy-3-methyl-5-phenyl-(N ⁴-phenylthiosemicarbazone)pyrazoline (H₂L), were synthesized and characterized by elemental analysis, IR, NMR (¹H, ¹³C) spectroscopies and X-ray crystallography techniques. Our studies revealed that H₂L has formed as 5-hydroxy-4,5-dihydropyrazoline derivative in orthorhombic, Pbca space group with a = 15.4330(3) ?, b = 11.5427(2) ?, c = 18.1440(3) ? whereas [Ph₂Sn(L)]·DMF crystallizes with two independent molecules (a and b) in the asymmetric unit in triclinic system, Pī space group with a = 9.2795(1) ?, b = 15.8315(2) ?, c = 19.9895(3) ?, α = 100.855(1)°, β = 92.985(1)°, γ = 102.243(1)°. In molecule a, the central Sn(IV) atom adopts a distorted tetragonal–pyramidal (TTP) geometry with N2 atom at apical position, while in molecule b the Sn(IV) occupies the centre of a trigonal-bipyramid (TBP) with N2 atom of the ONS-tridentate ligand and both Ph groups occupying equatorial positions. One molecule of DMF (crystallization solvent) helps in stabilizing the crystal structure.     

Synthesis,characterization and single crystal x-ray analysis of a complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine

Complex of iron(II) bis(2,4-dimethylphenyl)dithiophosphate with 4-ethylpyridine [{(2,4- (CH₃)₂C₆H₃O)2PS2}2Fe{NC₅H₄(C₂H₅)-4}₂] is synthesized and characterized by elemental analysis, magnetic moment, IR spectroscopy and single crystal X-ray analysis. Complex crystallizes in the monoclinic sp. gr. P2₁/n, Z = 2. Crystal structure consists of mononuclear units with Fe(II) ion chelated by four S atoms of the two diphenyldithiophosphate ligands in bidentate manner. N atoms from two 4-ethylpyridine ligands are axially coordinated to the Fe(II) atom leading to an octahedral geometry.     

Synthesis,Crystal and Molecular Structure of Cd2(sacch)4(Im)4

The title compound has been synthesized and its crystal structure determined at room temperature. Cd₂(Sacch)₄(Im)₄ F.W. = 1225.83, monoclinic. Space group: C2/c, Z = 4, a = 20.065(3) Å, b = 11.164(4) Å, c = 20.697(6) Å, β = 94.69(5)°, The coordination polyhedron of Cd(II) correspond to a five-coordinate trigonal-bipyramid. In the title complex, two of the saccharin groups act as monodentate ligands. The other two act as bidentate ligands. The two Cd(II) ions are bridged by the two bidentate saccharin groups and the distance is 4.75 Å.     

1-Phenyldiazenyl-8-Phenylhydrazononaphthalene-7(8H)-One-2-ol: Co-Existence of Azo-Hydroxy and Hydrazo-Keto Forms

Abstract  

The compound crystallizes in the triclinic P[`1] P\bar{1} space group and unit cell dimensions of a = 8.158 ?, b = 12.490 ?, c = 17.129 ?; α = 93.24°, β = 94.72°, γ = 97.61° and Z = 4. The structure was solved by direct methods and refined to an R1 value of 0.0890 on 2,278 observed reflections. There are two molecules in the asymmetric residue unit of the compound. In the title compound C₂₂H₁₆N₄O₂, two diazene groups at C1 and C8 and two hydroxy groups at C2 and C7 bring into play a unique azo-hydrazo equilibrium in which azo-hydroxy and hydrazo-keto forms co-exist in the molecule. The hydrazone H atom and the keto O atom are linked by an intramolecular N–H···O hydrogen bond on the other hand the hydroxy H atom and the azo N atom are linked by two intramolecular O–H···N hydrogen bonds.     

Crystal Structure and Characterization of [Ni(RPOEt)<Subscript>2</Subscript>(C<Subscript>2</Subscript>H<Subscript>5</Subscript>OH)<Subscript>2</Subscript>](ClO<Subscript>4</Subscript>)<Subscript>2</Subscript> [RPOEt = bis{(diphenylphosphinyl)methyl}ethyl phosphinate]

Abstract  

The compound [Ni(RPOEt)₂(C₂H₅OH)₂](ClO₄)₂ (1) [RPOEt = bis{(diphenylphosphinyl)methyl}ethyl phosphinate] has been prepared in the form of single crystals and characterized by elemental and thermal analyses, IR spectroscopy and by a single crystal X-ray diffraction study. The complex crystallizes in the triclinic P[`1] P\bar{1} space group with a = 9.8773(5), b = 13.741(1), c = 14.287(1) ?, α = 64.313(9), β = 70.280(5), γ = 89.973(7)o, V = 1620.5(2) ?³, and Z = 1. The nickel(II) atom in 1, situated at the centre of symmetry, is coordinated by four oxygen atoms from two RPOEt ligands and two oxygen atoms from two ethanol molecules in a slightly distorted octahedral environment. The third phosphoryl-oxygen atom from the phosphinate ligand is hydrogen bonded to the oxygen atom of the ethanol molecule coordinated to nickel(II). The complex [Ni(RPOEt)₂(C₂H₅OH)₂]²⁺ cations are linked by the C–H···O hydrogen bonds into one-dimensional chains and by the composite π···π and C–H···π phenyl interactions into a final three-dimensional structure.     

Crystal Structure and Magnetic Properties of the Dinuclear MnII Compound [Mn2(bpy)4(2-ClC6H4COO)2](ClO4)2·2EtOH

Abstract  

The synthesis and crystal structure of the dinuclear manganese (II) compound [Mn₂(bpy)₄(2-ClC₆H₄COO)₂](ClO₄)₂·2EtOH is described. The complex crystallizes in the monoclinic system, space group P2₁/n with a = 12.2067(18), b = 17.335(3), c = 13.706(3) ? and β = 92.606(8)°. In this structure, two manganese ions are bridged by two 2-chlorobenzoate ligands in a syn–anti mode. The hexa-coordination of each manganese is completed by two 2,2′-bipyridine ligands. Two perchlorate anions and two molecules of ethanol complete the packing. In order to check the magnetic properties previously reported from a powder sample, new magnetic studies have been carried out from a crystal sample, obtaining J = −1.79 cm⁻¹ and g = 2.00 (H = −JS ₁ ·S ₂ ).     

A Tetranuclear Nickel(II) Cubane Complex with <Emphasis Type="Italic">O</Emphasis>-Vanillin Ligand

Abstract  

A novel cubane complex with formula of [Ni(μ₃-OCH₃)L(CH₃OH)]₄ (1) has been successfully assembled by using o-vanillin as multidentate ligand. Each Ni(II) ion is six coordinate, being bound to four oxygen atoms from four methanol molecules, one phenoxido oxygen atom and one aldehyde oxygen atom from the o-vanillin ligand. The cubane structure is characterized by a Ni₄O₄ core assembled from four nickel atoms and four deprotonated, bidentate o-vanillin ligands and the cubic array of alternating nickel and oxygen atoms give intracluster metal–metal separations of 3.054(1) and 3.076(1) ? respectively. Preliminary magnetic studies suggest the existence of a weak antiferromagnetic coupling between the nickel ions.     

Hydrogen Bonding Patterns in Trimethoprimium Cinnamate 1.52 Hydrate

Abstract  

In the title compound, [C₁₄H₁₉N₄O₃ ⁺, C₉H₅ O₂ ⁻, H₂O, O0.52] the asymmetric unit contains a protonated trimethoprim cation and a cinnamate anion and two water molecules. The crystal structure was determined by single crystal X-ray diffraction. This compound crystallized in the triclinic system; space group P−1 with the unit cell parameters a = 10.010(2) ?, b = 10.339(3) ?, c = 13.486(8) ?, α = 105.32(3)°, β = 109.88(3)°, γ = 100.89(3)°, V = 1204.6(10) ?³, Z = 2. The cinnamate group is disordered. The trimethoprim (TMP) molecule is protonated at one of the pyrimidine nitrogen atoms. The carboxylate group of the cinnamate anion interacts with the protonated pyrimidine atom N1 and the 2-amino group via a pair of N–H···O hydrogen bonds, generating the R₂²(8) ring motif. The inversion related TMP cations are paired via N–H···N hydrogen bonds. In addition to the base pairing, the O1W atom bridges the 2-amino and 4-amino groups on either side of the paired bases, resulting in a self complementary DADA array. Two inversion related TMP cations and water molecules (O1W) are linked via N–H···O and O–H···O hydrogen bonds, forming a 22 membered ring with graph-set R₄⁴(22).     

Hydrogen Bond Ring Patterns of the Hydrated Molecular Salt of 4-Carboxybenzeneboronate with Cyclopentylammonium

Abstract  

The title molecular salt (cyclopentylammonium)·(4-carboxybenzeneboronate)·(H₂O)₃ was prepared by solution crystallization from 4-carboxybenzeneboronic acid and cyclopentylamine in a 1:1 stoichiometric ratio. The crystal belongs to the monoclinic space group Cc with a = 16.9273(5), b = 10.3387(3), c = 9.7475(3) ? and β = 107.014(2)°. X-ray single crystal structure analysis reveals that a molecular salt formed, with H transfer from the carboxylic acid group of the starting 4-carboxybenzeneboronic acid to the amine cyclopentylamine. The boronic acid functional group hydrogen bonds to the carboxylate anion, while the ammonium cation on the cyclopentyl ring hydrogen bonds to two water molecules and the carboxylate anion. A total of 11 hydrogen bonds are formed, resulting in a 2-D network made up of five unique hydrogen bonded rings to ultimately produce an extended 3-D hydrogen bonded architecture. The title molecular salt is compared to related salts having the boronic acid functional group.