Intermolecular Sb Research Articles

Coordinative Unsaturation in an Antimony(III)-Complex with the 2-Salicylidenaminophenolato Ligand: Synthesis, Crystal Structure, Spectroscopic Analysis, and DFT Studies

In this work, the synthesis and structure of an antimony complex with an aromatic, asymmetric tridentate ligand without an Sb-C bond were studied. Ethoxy(2-salicylidenaminophenolato)antimony(III) was studied with NMR, UV-Vis, and IR spectroscopy and the molecular structure was determined by single crystal X-ray diffraction. The antimony atom is formally tetracoordinate in this molecule. Coordinative unsaturation becomes visible in the solid-state structure where intermolecular Sb…O interactions supplement the coordination sphere of the antimony atom to be hexacoordinated. Quantum chemical calculations were performed in order to obtain a better understanding of the bond properties in the antimony complex. These show a spherical distribution of the lone pair at antimony and polar shared bonds from antimony to the heteroatoms of the tridentate ligand.

Metalloid Chalcogen–pnictogen σ-hole bonding competition in stibanyl telluranes

In this manuscript a curious behavior observed in the solid state of several X-ray structures retrieved from the Cambridge structural database (CSD) is described and analyzed. These structures have in common the presence of a metalloid–metalloid pnictogen (Pn)–chalcogen (Ch) covalent bond (i.e., Sb–Te bond) in the structure. The Sb–Te bond presents different σ-holes at both ends of the bond in terms of size and intensity. These compounds have a tendency to form short intermolecular Sb•••Te interactions in the solid state. The aim of this work is to investigate, by using dispersion-corrected density functional theory (DFT-D3) calculations, whether the Sb•••Te contacts observed in the solid state correspond to PnB (Sb is the Lewis acid) or ChB (Te is the Lewis acid). Moreover, using two model stibanyl telluranes, the interaction energies with a series of Lewis bases and anions using both ends of the Sb–Te covalent bond have been computed to investigate which side (PnB or ChB donor) is able to establish stronger interactions with common electron rich atoms. Finally, several computational tools such as the quantum theory of atoms-in-molecules (QTAIM), noncovalent interaction plot (NCIPlot) index and electron localization (ELF) function (2D and 3D maps) have been used to further characterize the physical nature of the Sb•••Te interactions. The results reported herein suggest that in the Sb•••Te contacts the Te atom acts as σ-hole donor and the Sb as electron density donor.

Low-Valent, Multiply Bonded, Trigonal-Planar Sb Complex: Rational Syntheses, Dual Acidic/Basic Properties, and Unexpected Semiconducting Characteristics.

A 4-center, 6π-conjugated, multiply bonded trigonal-planar complex, [Sb{Cr(CO)5}3]- (1), was synthesized via the hydride abstraction of [HSb{Cr(CO)5}3]2- (1-H) with HBF4·H2O, with the release of high yields of H2. The oxidation state of the Sb atom in [Et4N][1] was well-defined as 0, which was evidenced by X-ray photoelectron spectroscopy and X-ray absorption near-edge structure. The distinct color-structure relationship of this low-valent Sb complex 1 toward a wide range of organic solvents was demonstrated, as interpreted by time-dependent density functional theory calculations, allowing the trigonal-planar 1 and the tetrahedral solvent adducts to be probed, revealing the dual acid/base properties of the Sb center. In addition, 1 showed pronounced electrophilicity toward anionic and neutral nucleophiles, even with solvent molecules, to produce tetrahedral complexes [(Nu)Sb{Cr(CO)5}3]n- [1-Nu; n = 2, Nu = H, F, Cl, Br, I, OH; n = 1, Nu = PEt3, PPh3, N,N-dimethylformamide (DMF), acetonitrile (MeCN)]. On the contrary, the Fe/Cr hydride complex [HSb{Fe(CO)4}{Cr(CO)5}2]2- (2-H) was obtained by treating 1 with [HFe(CO)4]-. Upon hydride abstraction of 2-H with HBF4·H2O or [CPh3][BF4], a multiply bonded Fe/Cr trigonal-planar complex, [Sb{Fe(CO)4}{Cr(CO)5}2]- (2), was produced in which the oxidation coupling Sb2-containing complexes [Sb2Cr4Fe2(CO)28]2- (3-Cr) and [HSb2Cr3Fe2(CO)23]- (3-H) were yielded as final products. Complex 3-Cr exhibited dual Lewis acid/base properties via hydridation and protonation reactions, to form 2-H or 3-H, respectively. Surprisingly, [Et4N][1] possessed a low energy gap of 1.13 eV with an electrical conductivity in the range of (1.10-2.77) × 10-6 S·cm-1, showing that [Et4N][1] was a low-energy-gap semiconductor. The crystal packing, crystal indexing, and density of states results of [Et4N][1] further confirmed the efficient through-space conduction pathway via the intermolecular Sb···O(carbonyl) and O(carbonyl)···O(carbonyl) interactions of the 1D anionic zigzag chain of 1.

Phosphine chalcogenide complexes of antimony(III) halides

Three series of phosphine chalcogenide complexes of the antimony(III) halides SbX3 (X = F, Cl, Br, or I) have been synthesized and characterized by spectroscopic and crystallographic methods. Complexes of the generic formulae (Cy3PO)SbX3 (X = F (1a), Cl (1b), or Br (1c)), (Cy3PO)2SbX3 (X = F (2a), Cl (2b), or Br (2c)), and (Cy3PS)SbX3 (X = Cl (3b), Br (3c), or I (3d)) were synthesized via the treatment of solutions of SbX3 with OPCy3 and SPCy3, respectively. Derivatives of (Cy3PO)SbX3 were characterized by single crystal X-ray diffraction for 1a and 1b and crystallize as dimers through symmetry related intermolecular Sb–X interactions, providing the first structurally characterized examples of this class of complex. Derivatives of (Cy3PS)SbX3 (3b–3c) adopt analogous dimeric structures in the solid state. The solid-state structure of (Cy3PO)2SbCl3 (2b) is consistent with the previously reported structures of bis-phosphine oxide complexes of antimony(III), with a square pyramidal Sb center and cis-configured OPCy3 ligands. The phosphine chalcogenide complexes of SbX3 display configurations that are consistent with the perceived trans-labilizing properties of the ligands/substituents.

The Origin of Thermochromic Behavior in Distibines: Still an Open Question

A detailed structural investigation of Sb2Et4 using an in situ crystallization technique clearly shows that thermochromic behavior of distibines cannot be solely attributed to the formation of intermolecular Sb···Sb interactions in the solid state. Both the yellow and the red phase of Sb2Et4 showed almost identical bond lengths and angles including rather short intermolecular Sb···Sb bond distances.

Expansion of Antimonato Polyoxovanadates with Transition Metal Complexes: (Co(N3C5H15)2)2[{Co(N3C5H15)2}V15Sb6O42(H2O)]·5H2O and (Ni(N3C5H15)2)2[{Ni(N3C5H15)2}V15Sb6O42(H2O)]·8H2O

Two new polyoxovanadates (Co(N(3)C(5)H(15))(2))(2)[{Co(N(3)C(5)H(15))(2)}V(15)Sb(6)O(42)(H(2)O)]·5H(2)O (1) and (Ni(N(3)C(5)H(15))(2))(2)[{Ni(N(3)C(5)H(15))(2)}V(15)Sb(6)O(42)(H(2)O)]·8H(2)O (2) (N(3)C(5)H(15) = N-(2-aminoethyl)-1,3-propanediamine) were synthesized under solvothermal conditions and structurally characterized. In both structures the [V(15)Sb(6)O(42)(H(2)O)](6-) shell displays the main structural motif, which is strongly related to the {V(18)O(42)} archetype cluster. Both compounds crystallize in the triclinic space group P1 with a = 14.3438(4), b = 16.6471(6), c = 18.9186(6) Å, α = 87.291(3)°, β = 83.340(3)°, γ = 78.890(3)°, and V = 4401.4(2) Å(3) (1) and a = 14.5697(13), b = 15.8523(16), c = 20.2411(18) Å, α = 86.702(11)°, β = 84.957(11)°, γ = 76.941(11)°, and V = 4533.0(7) Å(3) (2). In the structure of 1 the [V(15)Sb(6)O(42)(H(2)O)](6-) cluster anion is bound to a [Co(N(3)C(5)H(15))(2)](2+) complex via a terminal oxygen atom. In the Co(2+)-centered complex, one of the amine ligands coordinates in tridentate mode and the second one in bidentate mode to form a strongly distorted CoN(5)O octahedron. Similarly, in compound 2 an analogous NiN(5)O complex is joined to the [V(15)Sb(6)O(42)(H(2)O)](6-) anion via the same attachment mode. A remarkable difference between the two compounds is the orientation of the noncoordinated propylamine group leading to intermolecular Sb···O contacts in 1 and to Sb···N interactions in 2. In the solid-state lattices of 1 and 2, two additional [M(N(3)C(5)H(15))(2)](2+) complexes act as countercations and are located between the [{M(N(3)C(5)H(15))(2)}V(15)Sb(6)O(42)(H(2)O)](4-) anions. Between the anions and cations strong N-H···O hydrogen bonds are observed. In both compounds the clusters are stacked along the b axis in an ABAB fashion with cations and water molecules occupying the space between the clusters. Magnetic characterization demonstrates that the Ni(2+) and Co(2+) cations do not significantly couple with the S = 1/2 vanadyl groups. The susceptibility data can be successfully reproduced assuming a distorted ligand field for the Co(2+) ions (1) and an O(h)-symmetric Ni(2+) ligand field (2).

A C2-symmetric antimonato polyoxovanadate cluster [V16Sb4O42(H2O)]8− derived from the {V18O42} archetype

The new antimonato polyoxovanadate [V(IV)(16)Sb(III)(4)O(42)(H(2)O)](8-) cluster (1a) is the main structural motif of the solvothermally obtained compound {(trenH(2))Zn(tren)}(2)[V(16)Sb(4)O(42)(H(2)O)]·xH(2)O (x = 6-10) (1) (tren = tris(2-aminoethyl)amine). The C(2)-symmetric cluster structure is closely related to the {V(18)O(42)} archetype. 1 crystallizes in the monoclinic space group C2/c with a = 30.7070(19) Å, b = 13.9512(5) Å, c = 23.1435(14) Å, β = 128.076(6)°, and V = 7804.8(7) Å(3). The orientation of the [Sb(III)(2)O(5)](4-) groups in each cluster leads to intermolecular Sb···O contacts and the formation of channels between the clusters. [Zn(tren)(trenH(2))] complexes with trigonal bipyramidal coordination environments are located between the [V(16)Sb(4)O(42)(H(2)O)](8-) anions, and form a three dimensional network with them via strong N-H···O hydrogen bonds. Up to 250 °C crystal water molecules are emitted, which are reversibly incorporated in humid air.

Structural Characterization of Et4Sb2 and Et4Bi2

The solid-state structures of Et4Sb2 (1) and Et4Bi2 (2) were determined by single-crystal X-ray diffraction. Single crystals of 1 and 2 were grown in a closed quartz glass capillary under an inert argon atmosphere on the diffractometer using a specific IR-laser-assisted technique. 1 shows short intermolecular Sb···Sb interactions, whereas the closest Bi···Bi distances are longer than the sum of the van der Waals radii.

Structural systematics in antimony tris(xanthates): Sb(S2COR)3

Abstract Crystallography shows the hexagonal form of Sb(S2COEt)3 to have three-fold symmetry in which the antimony atom is chelated by asymmetrically coordinating xanthate ligands, Sb—S = 2.5204(8) and 3.0603(11) Å. The lone pair of electrons projects out of the triangular face defined by the three weakly coordinating sulfur atoms. The crystal structure comprises layers that stack in an ... ABAB ... fashion in contrast to the previously determined trigonal form. A similar coordination geometry is found in the structure of Sb(S2CO—nPr)3. Molecules aggregate into a supramolecular helical chain via secondary Sb ... S interactions. Crystal data for C9H15O3S6Sb, hexagonal, P63, a = 14.642(4), c = 4.6674(10) Å, V = 866.6(4) Å3, Z = 2, R = 0.021; C12H21O3S6Sb, monoclinic, P21/c, a = 14.671(5), b = 8.898(3), c = 17.185(6) Åb = 111.288(4)°, V = 2090.3(12) Å3, Z = 4, R = 0.042. An analysis of all available Sb(S2COR)3 structures shows the adoption of molecules with C 3 or C s symmetry. In the case of the latter, well defined intermolecular Sb ... S contacts lead to supramolecular double chains. For the structures with C 3 symmetry, supramolecular aggregation patterns are more varied and less dependent on Sb ... S contacts.

Synthesis, characterizations and crystal structures of new antimony (III) complexes with dithiocarbamate ligands

Eight new antimony (III) complexes containing dithiocarbamate ligands (R 2NCS 2) 2SbBr [R 2NCS 2 = OC 4H 8NCS 2 ( 1), C 2H 5NC 4H 8NCS 2 ( 2), Me 2NCS 2 ( 3), C 4H 8NCS 2 ( 4)] and (R 2NCS 2) 3Sb[R 2NCS 2 = C 5H 10NCS 2 ( 5), Bz 2NCS 2 ( 6), Et 2NCS 2 ( 7), (HOCH 2CH 2) 2NCS 2 ( 8)] have been synthesized by the reactions of antimony (III) halides with dithiocarbamate ligands in 1:2 or 1:3 stoichiometries. All the complexes have been characterized by elemental analysis, melting point as well as spectral [IR and NMR ( 1H and 13C)] studies. The crystal structures of complexes 1, 5 and 8 have been determined by X-ray single crystal diffraction, and their electrochemical character has also been studied. The structure of complex 1 shows that the five-coordinated antimony (III) atom adopts a distorted trigonal bipyramidal geometry. Furthermore, the supramolecular structure of 1 consists of a one-dimensional linear molecular chain which is built up by intermolecular Sb⋯S and S⋯S weak interactions. In complex 5, the central antimony atom is six-coordinated with a distorted octahedral geometry and the supramolecular structure is constructed by C–H⋯S weak hydrogen bonds. The structure of complex 8 is stabilized by strong intermolecular hydrogen bonds between the ethanolic hydrogens (O–H).

Preparation and characterization of catena-[bromo(tetrahydrofuran- O)(2-thioxo-1,3-dithiole-4,5- dithiolato)antimony(III)], [Br(THF)Sb(dmit)] n

Reaction of SbBr 3 with Me 2Sn(dmit) (1:1 mol ratio) in Me 2CO produces unsolvated [SbBr(dmit)] n , which on crystallization from THF solution gives the title compound, [SbBr(dmit)(THF)] n ( 5) [dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato]. Taking into account the lone pair on Sb, the geometry at Sb is pseudopentagonal bipyramidal, with intramolecular bonds, Sb–Br 2.5833(3) Å, Sb–S thiolato, of the chelating dmit ligand, 2.4723(7) and 2.4936(6) Å, Sb–O of the monodentate THF ligand 2.658(2) Å and intermolecular bonds, Sb–S thioxo [3.2466(7) and 3.2522(8) Å] of two other dmit ligands. The intermolecular Sb–S bonds link the molecules into pairs of chains, which are further reinforced by π–π interactions involving the dmit ligands. There are no significant interactions between the chain pairs. Each dmit ligand acts as a μ 3 bridge linking three different Sb atoms, with one bidentate (chelating) mode of bonding and two monodentate interactions.

Crystal Structure of .MU.-Oxo-Bis[aquapyridine-2,6-dicarboxylato-antimony(III)

The crystal structure of [Sb(pydc)(H2O)]2O was determined by X-ray diffraction. This compound crystallizes in the monoclinic system, space group P21/n, with the following unit-cell parameters: a = 5.234(1)A, b = 11.164(2)A, c = 14.331(3)A, β = 97.49(3)°. The final R value is 0.0384 with 1226 reflections. This compound is a five-coordinated binuclear complex in which each of the two metal fragments are arranged via weak intermolecular Sb…O interactions. The binuclear units join together by axial Sb-O, and thus make a distorted square pyramid binuclear complex. The existence of a hemi-directed configuration in the complex is due to the activity of the lone electron pair on antimony.

Solvothermal Synthesis, Crystal Structure, and Properties of the First Zinc Containing Thioantimonate(III) [Zn( tren )] 2 Sb 4 S 8 �0.75 H 2 O

Yellow crystals of the title compound were obtained under solvothermal conditions reacting elemental Zn, Sb, and S in a solution of tris(2-aminoethyl)amine (= tren) and water. The compound crystallises in the monoclinic space group P21/c with a=13.0247(7), b=22.308(2), c=12.1776(6) A, and β=105.352(6)°. In the structure of [Zn(tren)]2Sb4S8·0.75 H2O two [Zn(tren)]2+ cations are bound to the [Sb4S8]4− anion via S atoms. The Zn2+ ions are in a trigonal bipyramidal environment of four N atoms of the tetradentate tren ligand and one S atom of the [Sb4S8]4− anion. The anion is formed by SbS3 and SbS4 units which share common corners and edges. The interconnection mode yields three different non-planar Sb2S2 heterorings. The shortest intermolecular Sb–S distance amounts to about 3.7 A, and taking this long separation into account undulated chains running along [001] are formed with the water molecules residing in the pocket-like cavities. Upon heating the compound decomposes in one step starting at about 240°C. The final decomposition product was identified as ZnS and Sb2S3 by X-ray powder diffractometry. Additionally, spectroscopic data as well as synthetic procedures for [Zn(tren)]2Sb4S8·0.75 H2O are reported.

Sb⋯S and S⋯S interactions in the first neutral and oxidized diphenylstibino (Ph2Sb–) derivatives of the redox active tetrathiafulvalene (TTF) core

The preparation of the monostibines o-Me2TTF–SbPh2 (1) and Me3TTF–SbPh2 (2), the ortho distibine o-Me2TTF(SbPh2)2 (3) and the tetrastibine TTF(SbPh2)4 (4) is described together with their electrochemical properties and the X-ray crystal structures of the neutral 1 and 3. In the former, one intermolecular Sb⋯S contact completes the co-ordination sphere of the antimony atom while in 3 the TTF moieties stack on top of each other with no evidence for Sb⋯S interactions. Electrocrystallisation of 2 in the presence of [n-Bu4N]2[Mo6O19] affords a 2 ∶ 1 salt, [2]2[Mo6O19] where the 2+˙ cation radical species are associated into diamagnetic [2]22+dyads through a strong HOMO⋯HOMO overlap interaction, separated from each other by the [Mo6O19]2− counter ions.

Preparation and Characterization of a Series of Novel Mono(metallo)stibanes [M]Sb(CF3)2

Isolable mono(metallo)stibanes of the type [M]Sb(CF3)2 ([M] = (CO)5Mn (3a), (CO)5Re (3b), Cp(CO)3Cr (3c), Cp(CO)3Mo (3d), C5Me5(CO)3W (3e)) are formed quantitatively by reactions of Sb(CF3)3 (1) with the corresponding hydride complexes [M]H (2) with elimination of trifluoromethane. Structural analyses of the derivatives 3a and 3e by X-ray diffraction show a considerable shortening of the M−Sb bonds in comparison with the sum of the single bond radii. In the crystal lattice of 3a a significant intermolecular Sb···Sb interaction of pairs of molecules is observed.

Complexes with cyclo-Sbn Ligands

The four membered organoantimony ring (tBuSb)4 (1) reacts with [(C5R5)Mo(CO)3]2, (R = H, Me) to form the tetrahedrane derivatives [(C5H5)Mo(CO)2’2Sb2 (2), (C5H5)Mo(CO)2Sb3 (3), [(C5Me5)Mo(CO)2]2Sb2 (4), and [(C5Me5)Mo(CO)2Sb3] (5). An organo antimony ring, (C5Me5)Mo(CO)3(tBu3Sb4) (6), is also formed. In the crystalline state both cyclo-Sb3 complexes, 3 and 5 are associated through close intermolecular Sb⋯Sb contacts to form supramolecular layers.

On the 5-thia-(substituted)-1-oxa-4,6-dithia-5-stibocanes. Synthesis and characterization of O(CH 2CH 2S) 2SbS 2P(OC 2H 5) 2 and crystal and molecular structure of (CH 2CH 2S) 2SbSCH 2CH 2OCH 2CH 2SSb(SCH 2CH 2) 2O, a compound with two different eight-membered ring conformations

The stibocane O(CH 2CH 2S) 2SbS 2P(OC 2H 5) 2 ( 1) was prepared by reacting O(CH 2CH 2S) 2SbCl and KS 2P(OC 2H 5) 2, in anhydrous benzene, and characterized by spectroscopic (IR, MS, 1H, 13C and 31P 1H NMR) methods. The crystal and molecular structure of O(CH 2CH 2S) 2SbSCH 2CH 2OCH 2CH 2SSb(SCH 2CH 2) 2O ( 2), obtained as a side product during the attempts to grow crystals of the dithiophosphato derivative, was determined by X-ray diffractometry. The compound is triclinic, space group P 1, a = 7.994(1), b = 10.495(1), c = 14.562(2) A ̊ , α = 77.90(1), β = 85.50(1), γ = 69.02(1)°, V = 1115.3(2) A ̊ 3, Z = 2 . The molecule of 2 contains two SbS 2C 4O rings with different conformations, i.e. chair-chair for Sb(1) and boat-chair for Sb(2). In both heterocyclic rings strong transannular Sb(1)…O(1) (2.734(3) Å) and Sb(2)…O(3) (2.637(4) Å) interactions are present. The O(2) atom of the bridging ligand also exhibits intramolecular Sb(1)…O(2) (2.895(3) Å) and Sb(2)…O(2) (3.156(3) Å) interactions. In the crystal form 2 is associated in pairs through weak, intermolecular Sb(2)…S secondary interactions (3.733(1) Å), thus resulting in different coordination polyhedra for the antimony atoms in the same molecule.

Syntheses, Structures, and Equilibria of o‐, m‐, p‐Tolyl‐ and Phenylantimony Rings

AbstractExchange reactions of R3Sb (R = o‐Tol, m‐Tol, p‐Tol) with SbCl3 in a 1:2 molar ratio give RSbCl2. Silylstibanes RSb(SiMe3)2 were obtained by reaction of RSbCl2 and Me3SiCl with Mg in THF. Slow access of air to solutions of RSb(SiMe3)2 afforded orange crystals of the composition (RSb)n. Crystal structures were determined by X‐ray crystallography for R = o‐Tol and m‐Tol as stacks of (RSb)6 rings in the chair conformation with equatorial substituents. In the crystals of (m‐TolSb)6 there are short intermolecular Sbb distances of 420 pm. Solutions of (RSb)n (R = Ph, o‐Tol, m‐Tol, p‐Tol) in C6D6 were analyzed by 1H‐NMR spectroscopy. They contain (RSb)5 and (RSb)4 in equilibria. Raman spectra of (PhSb)6 or (p‐TolSb)n show signals for Sbn at β = 151 or 153 cm‐1. 13C‐CP‐MAS‐NMR data of (p‐TolSb)n are reported.

Neutral thiolates of antimony(III) and bismuth(III)

A range of bismuth(III) and antimony(III) thiolates, Bi(SR)3(R = C6F5, 4-MeC6H4, 2,6-Me2C6H3 or 3,5-Me2C6H3) and Sb(SR)3(R = 4-MeC6H4 or 3,5-Me2C6H3) has been synthesised and the structures of the two antimony complexes have been determined. Both structures reveal a trigonal-pyramidal antimony centre bonded to three thiolate groups with, for the 4-MeC6H4 complex, additional intermolecular Sb ⋯ S interactions and, for the 3,5-Me2C6H3 complex, intermolecular arene to antimony interactions. The syntheses and structures of the organotransition-metal complexes [Bi(SC6F5){M(CO)3(η-C5H5)}2](M = Mo or W) are also reported in which the bismuth centre is bonded to one SC6F5 group and two M(CO)3(η-C5H5) fragments with no short intermolecular interactions.

Preparation and crystal structures of five organoantimony halides; ( p-tolyl)antimony(III) dichloride and dibromide, diphenylantimony(III) bromide, 2′-diyl)antimony(III) chloride and bis-(2′-chlorobiphenyl-2-yl)antimony(V) trichloride

Crystal structures are reported for four organoantimony(III) halides, i.e. ( p-tolyl)antimony dichloride ( 1) and dibromide ( 2), diphenylantimony bromide ( 3), (biphenyl-2,2′-diyl) antimony chloride ( 4) and a new antimony(V) compound, bis(2′-chlorobiphenyl-2-yl)antimony(V) trichloride ( 5), obtained by oxidising ( 4) with an excess of chlorine. The two tolyl compounds ( 1) and ( 2), which are isostructural and also isostructural with the corresponding phenyl derivatives, contain pyramidal CSbX 2 units. These are interlinked by (a) two weak intermolecular Sb ⋯ halogen interactions (mean 3.54 and 3.69 Å for the chloride and bromide, respectively), raising the antimony coordination number to five giving infinite chains, and (b) weak contacts between antimony and three of the carbon atoms of a symmetry-related tolyl group (mean 3.41 and 3.42 Å for the chloride and bromide, respectively). There are no intermolecular Sb ⋯ Br contacts in 3 but two Sb ⋯ C interactions (mean 3.64 Å) interconnect the pyramidal monomers. Such Sb ⋯ C interactions (mean 3.43 Å) are also present in the biphenylyl derivative 4, in which the CSbC angle in the pyramidal monomer is constrained to 81.0° by the short bite of the biphenylyl group. Loose dimers are formed in the solid state by Sb ⋯ Cl contacts at 3.71 Å. In contrast to the chlorine bridged dimeric structure of Ph 2SbCI 3, compound 5 is a distorted trigonal bipyramidal monomer in the solid state, providing the first example of an antimony(V) compound with chlorine atoms in both axial and equatorial sites. As expected, distances to the two axial chlorines are substantially longer (2.420(3), 2.421(3) Å) than that to the equatorial atom (2.280(3) Å). The greatest distortion is shown by the equatorial CSbC angle, which is increased to 137.1°, probably as a consequence of the steric requirements of the bulky chlorobiphenylyl groups.