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The reaction of 2,6-diformyl-4-methylphenyl disulfide with [Ni(tn)3]Cl2 (tn = 1,3-diaminopropane), in methanol and in the presence of NaBPh4 resulted in the isolation of [Ni2(L1)](DMF)2(BPh4)2 (I), (L1 = 15,95-dimethyl-3,7,11,15-tetraaza-1,9(1,3)-dibenzenacyclohexadecaphane-2,7,10,15-tetraene-12,92-bis(thiolate). This reaction represents a 2-electron solvent assisted reduction of the disulfide bond to form two thiolate ligands where methanol is converted to formaldehyde and the two nickel centres remained in the + 2 oxidation state. The crystal structure of I showed the two nickel(II) atoms are bridged by two thiolates in a binuclear Ni2S2 core inside of a macrocyclic framework. The IR spectrum showed a band at 1625 cm−1, assigned to the imine ν(C [dbnd]N) stretch of the macrocyclic ligand, and bands at 734, 706 cm−1, are assigned to the tetraphenylborate counter ions. This is the first example of solvent assisted S–S bond cleavage being used to prepare a dicompartmental macrocyclic complex.

Lead(II) tetrafluoroborate and hexafluorosilicate complexes with 2,2′-bipyridyl, 1,10-phenathroline and 2,2′:6′,2″-terpyridyl have been prepared from the ligand and lead salt in aqueous/MeCN. Crystal structures are reported for [Pb(bipy)2(SiF6)], [Pb(phen)2(SiF6)] and [Pb(bipy)2(BF4)2] which are dinuclear with each lead coordinated “cis” to the two diimines and with the bridging fluoroanions completing eight or nine-coordination. [Pb(phen)2(BF4)2] is eight-coordinate and mononuclear with “cis” diimines and two κ2-BF4− groups. [Pb(phen)2(H2O)2(SiF6)] is also mononuclear with a κ2-SiF62− group and two coordinated water molecules. Reaction of Pb(BF4)2 with 2,2′:6′,2″-terpyridyl gave only [Pb(terpy)3][BF4]2, but Pb(SiF6) produced [Pb(terpy)(H2O)(SiF6)], which is a chain polymer with bridging SiF62− groups and significant π-stacking of the imine rings. The work has identified a number of coordination modes of the SiF62− anion, which has been little used in coordination chemistry but proves to be versatile and also stable (to decomposition/hydrolysis).

Arsenic(III), antimony(III) and bismuth(III) compounds of the type, [M{S2P(OR)2}3] (where M = As, Sb and Bi; R = o-, m-, p-C6H4Me) were obtained by reactions of MCl3 with ammonium salts of the corresponding O,O′-ditolyl dithiophosphate on refluxing in benzene. These compounds were characterized by elemental analysis, IR, 1H NMR and 31P NMR spectroscopy. The single crystal X-ray structures of three representative compounds were determined. [As{S2P(OC6H4Me-m)2}3]·0.5C6H14 crystallizes as triclinic in the space group P 1 ¯ with a = 10.9396(1), b = 14.1891(2), c = 17.5359(2) A, α = 70.731(1), β = 84.734(1), γ = 74.205(1)°, Z = 4, V = 2472.37(5) A3. [Sb{S2P(OC6H4Me-m)2}3] and [Bi{S2P(OC6H4Me-m)2}3] both crystallize as monoclinic in the space group P21 with a = 12.4520(3), b = 22.8760(5), c = 16.2165(4) A, β = 93.022(1)°, Z = 4, V = 4612.9(2) A3 and with a = 12.4903(2), b = 22.9554(4), c = 16.1032(3) A, β = 92.4300(10)°, Z = 4, V = 4612.96(14) A3, respectively. In all three molecules, the central metal atom is surrounded by all six sulfur atoms of the three chelating anisobidentate O,O′-ditolyl dithiophosphate groups in a pseudo trigonally distorted octahedron with a lone pair positioned on one of the triangular octahedral faces. The three metal sulfur bonds adjacent to the lone pair (capped face) are longer than the three furthest from the lone pair (uncapped face). Inter-ligand angles between the longer bonds are greater than those between the shorter bonds.

Bis(O,O'-ditolyl/dibenzyl dithiophosphato)cobalt(II) complexes with pyridine ligands of the type [Co{S2P(OR)(2)}(2)(C5H5N)(2)] (R = o-, m-, p-C6H4Me, CH2Ph) have been synthesized by the reaction of CoCl2(C5H5N)(2) and the corresponding ammonium salt of O,O'-ditolyl/dibenzyl dithiophosphate in methanol. These newly synthesized adducts were characterized by elemental analysis, IR, UV-Vis spectroscopy, magnetic susceptibility measurements and single crystal X-ray diffraction. These structures confirm that in the pyridine complex the geometry around the cobalt metal centre is distorted octahedral, and in the amine complex it is distorted trigonal bipyramidal. (C) 2008 Elsevier Ltd. All rights reserved.

Bis(O,O-dialkylmonothiophosphato)cobalt(II) complexes of the type [Co{O(S)P(OR)2}2] (where R = Prn, Pri, Bun) were prepared under anhydrous conditions by the reaction of cobalt(II) dichloride hexahydrate with the sodium salts of dialkyl monothiophosphoric acids. The reactions of these blue tetrahedral complexes with nitrogen bases such as pyridine (C5H5N or py) and 2,2-bipyridyl (C10H8N2 or bipy) resulted in the pink/orange octahedral adducts [Co{O(S)P(OPri)2}2(C5H5N)4], [Co{O(S)P(OPrn)2}2(C10H8N2)2] and [Co{O(S)P(OBun)2}2(C10H8N2)2]. These compounds were characterized by elemental analysis, IR spectroscopy, magnetic measurements and the single crystal X-ray diffraction structures of two of the adducts of the monothiophosphate complexes, [Co{O(S)P(OPri)2}2(C5H5N)4] and [Co{O(S)P(OPrn)2}2(C10H8N2)2], which are the first examples of this class of compounds. [Co{O(S)P(OPri)2}2(C5H5N)4] crystallizes as triclinic in the space group P 1 ¯ with the cell parameters a = 9.0515(4) A, b = 10.1629(5) A, c = 11.8468(5) A, α = 88.389(3)°, β = 71.984(4)°, γ = 69.181(3)°, Z = 1, V = 964.57(8) A3 and [Co{O(S)P(OPrn)2}2(C10H8N2)2] crystallizes as monoclinic in the space group C2/c with the cell parameters, a = 8.404(2) A, b = 22.855(5) A, c = 18.913(4) A, β = 97.56(3)°, Z = 4, V = 3601(1) A3. These structures contain a unidentate bonding of the monothiophosphate ligands through oxygen, with the geometry of the CoO2N4 coordination sphere around cobalt being distorted octahedral.

A series of binuclear oxomolybdenum(V) O,O′-ditolyl dithiophosphate complexes, Mo2O3[S2P(OR)2]4 (R = o-, m-, p-C6H4Me) were synthesized by drop wise addition of aqueous solution of the ammonium salt of O,O′-ditolyl dithiophosphoric acid into an acidic solution of sodium molybdate with constant stirring to yield purple solids. Dioxomolybdenum(VI) O,O′-ditolyl dithiophosphate complexes, MoO2[S2P(OR)2]2 (R = o-, m-, p-C6H4Me and CH2C6H5) were also synthesized by reducing Mo2O3[S2P(OR)2]4 with OPPh3 in benzene to yield yellow solids. These complexes were characterized by elemental analysis and IR, 1H and 31P NMR spectroscopy and, in three cases, by X-ray crystallography. In Mo2O3[S2P(OC6H4Me-o)2]4 and Mo2O3[S2P(OC6H4Me-m)2]4, the environment around each molybdenum atom can be described as the expected distorted octahedral, consisting of one terminal and one bridging oxygen along with the four chelating sulfur atoms of the dithio ligands, with one Mo–S distance being significantly longer than the other three. In MoO2[S2P(OC6H4Me-p)2]2 the geometry around the Mo atom is again distorted octahedral with two cis terminal oxygen atoms and two anisobidentate dithiophosphate ligands.

Reactions of Ni[S2P(OR)2]2(R = o-, m- and p-C6H4Me) with nitrogen donor ligands, viz. pyridine (C5H5N or py), 2,2?-bipyridyl (C10H8N2 or bipy) and 2,9-dimethyl-1,10-phenanthroline (C14H12N2 or dmphen) were carried out in benzene to yield green paramagnetic solids. These adducts were characterized by UV–visible and IR spectroscopy, magnetic measurements and, in two cases, by X-ray crystallography, to indicate how the number of donor atoms and steric factors affect the Ni–S bonding. The molecular structures of 2,2?-bipyridylbis {O,O?-di(p-tolyl)dithiophosphate}nickel(II), Ni[S2P(OC6H4Me-p)2]2 · C10H8N2 and 2,9-dimethyl-1,10-phenanthrolinebis{O,O?-di(o-tolyl)dithiophosphate}nickel(II), Ni[S2P(OC6H4Me-o)2]2 · C14H12N2 · C6H6 are described. The geometry around nickel in the bipyridyl adduct is distorted octahedral with NiS4N2 coordination, whereas in the 2,9-dimethyl-1,10-phenanthroline adduct it is trigonal bipyramidal with NiS3N2 coordination in which one dithiophosphate moiety is bidentate and the other is monodentate.

Lithium 2-thienyltellurolate, generated from 2-thienyl lithium, reacts at -78 degrees C in THF with chloroethyl ethyl sulfide to give a (Te, S) ligand 1-ethylthio-2-[2-thienyltelluro]ethane (L) as a red oil. The complexes [PdCl2(L)] (1), [PtCl2(L)] (2), [Ag(L)(2)][ClO4] (3) and [CuBr(L)](2) (4) were synthesized. The complex [HgCl2(L)] on crystallization decomposed giving Th2TeCl2 (5) [where Th = 2-thienyl], which was characterized by X-ray diffraction on its single crystals. The ligand L and complexes 1-4 exhibit proton and carbon-13 NMR spectra, which are characteristic. The coordination through Te in 1-4 is indicated by downfield coordination shifts in the position of the TeCH2 signal of L. Complex I was characterized by X-ray diffraction on its single crystals. The geometry around Pd is square planar. The Pd-Te, Pd-S and Pd-Cl bond lengths are 2.5040(4), 2.273(1) and 2.322(1)/2.380(1) angstrom, respectively. There are intermolecular interactions between Te (coordinated to Pd) and Cl, and sulfur and Cl. The Te-Cl and S-Cl distances, 3.401 and 3.488 A, respectively, are shorter than the sum of the van der Waal's radii (3.81 and 3.55 A, respectively). The Pd-Pd distance between the two molecules is 3.4156(6) A, greater than the sum of van der Waal's radii (3.26 A). The structure of 5 is typical of that of a tellurium(IV) compound (saw-horse type). The two Te-Cl bond lengths are identical, 2.480(1) A. The geometry around Te in 5 can be best described as pseudo tetrahedral (trigonal bipyramidal with a lone pair on one corner of the triangle).

Reactions of dibromodioxobis(dimethylsulfoxide)molybdenum(VI) with sodium/potassium salts of N,N'-dialkyl dithiocarbamates or O-alkyl dithiocarbonates in 1:1 molar ratio in dichloromethane yield bromodioxomolybdenum(VI) complexes of the type, MoO2Br(S2CNR2)(OSMe2) (R = Et, Pr-n, Pr-i) or MoO2Br(S2COR)(OSMe2) (R = Et, Pr-n, Pr-i). These newly synthesized complexes were characterized by elemental analysis and IR, UV-Vis and H-1 NMR spectroscopy. Crystals of MoO2,Br-2(OSMe2)(2) and MoO2Br(2)(C12H8N2) • CH2Cl2 both have distorted octahedral environments around molybdenum with two cis-oxygen atoms and two trans-bromine atoms along with two cis-dimethylsulfoxide moieties in the former and 1,10-phenanthroline in the latter.

The (P, S) ligand 1-(ethylthio)-2-(diphenylphosphino) ethane (L) is synthesized by reacting Ph2PLi with CH3CH2SCH2CH2Cl. The yield is good (similar to 85%) and the method of preparation is simpler than the liquid ammonia based one reported earlier. Its complexation with Cu(I), Hg(II) and organometallic species of Ru(II) are explored. All the complexes and the ligand exhibit characteristic proton, carbon-13 and phosphorus-31 NMR spectra. The single crystal structure of the Hg(II) complex has been determined. It is found to be a three coordinate complex. The sum of the bond angles at Hg, viz. P(1)-Hg(1)-Br(1), P(1)-Hg(1)-Br(2) and Br(1)-Hg(1)-Br(2), is approximate to 360 degrees. Thus the geometry around Hg can best be described as essentially trigonal planar. The Hg(1)-P(1) bond length is 2.415(1) angstrom and the Hg-Br bond lengths are 2.5152(6) and 2.5952(6) angstrom. There exists a weak secondary interaction between Hg and the S donor site of the ligand [Hg(1)•••S(1) bond distance 3.063(1) A < sum of van der Waal's radii 3.35 A].

The synthesis and characterization of the organotriboroxinate salts [Me3NCH2CH2OH][B3O4Ph4] (1) and [NEt3H][B3O3Ph3(OH)] (3) are reported. Compound 3 contains the first example of a hybrid inorganic/organic triboroxinate anion. Compounds 1 and 3 have been structurally characterized by single-crystal X-ray diffraction studies, which reveal H-bond ion-pair interactions between anions and cations in both 1 and 3, and additional anion–anion H-bond interactions in 3. Compound 3 exists as a dimer in the solid-state. A single crystal X-ray diffraction study of the triarylboroxine, (4-MeOC6H4)3B3O3, is also reported.

Purple-coloured, tetra-coordinated Ni(II) complexes, Ni[S2P(OR)2]2 (R = o-, m-, p-OC6H4Me, Ph and CH2Ph) have been obtained by reaction of NiCl2 with salts of corresponding O,O′-diaryl(dibenzyl) dithiophosphates and have been characterized by elemental analysis, UV, IR, 1H, and 31P NMR spectroscopy. Trends in the data are discussed. The crystal structures of Ni[S2P(OC6H4Me-o)2]2, Ni[S2P(OC6H4Me-m)2]2 and Ni[S2P(OCH2Ph)2]2 are also described. Ni[S2P(OC6H4Me-o)2]2 crystallizes as monoclinic in the space group P21/n with cell parameters a = 9.069(2), b = 13.503(2), c = 23.735(4) A, α = 90.00°, β = 90.11(1)°, γ = 90.00°, V = 2906.6(8) A−3, Z = 4, R = 0.0351, Rw = 0.0787, Ni[S2P(OC6H4CH3-m)2]2 as triclinic in the space group P 1 ¯ with cell parameters a = 9.4675(4), b = 12.8568(5), c = 13.1174(6) A, α = 88.810(4)°, β = 83.416(5)°, γ = 73.711(4)°, V = 1522.4(1) A−3,Z = 2, R = 0.0354, Rw = 0.0830, and Ni[S2P(OCH2Ph)2]2 as triclinic in the space group P 1 ¯ with cell parameters a = 10.887(2), b = 14.081(3), c = 16.238(3) A, α = 72.70(3)°, β = 76.57(3)°, γ = 72.76(3)°, V = 2241.4(8) A−3, Z = 2, R = 0.0365, Rw = 0.0785. Each of these has a distorted square-planar geometry around nickel with MS4 coordination environment.

Five new complex salts [Pt(SC(NH2)2)4][dc] (dc = adipate (1), isophthalate (2), terephthalate (3), 4,4′-biphenyldicarboxylate (4), 1,4-naphthalenedicarboxylate (5)) have been characterized by single-crystal X-ray diffraction. Thiourea–carboxylate interactions have proven to be a reliable supramolecular synthon, yielding in all the examples charge-assisted hydrogen-bonded 3D networks via N–H⋯O interactions.

4-MeOC6H4Te-Na+ and Te2- generated in situ by reduction of (4-MeOC6H4Te)(2) and elemental Te, respectively, with sodium borohydride on reaction with 2-[3-(2-chloroethoxy)propyl]-6-methylpyridine in N-2 atmosphere results in 1-(4-methoxyphenyltelluro)-2-[3-(6-methyl-2-pyridyl)propoxy]ethane (L-I) 2-methyl-6-{3-[2-({2-[3-(6-methyl-2-pyridyl)propoxy]ethyl}telluranyl)eth oxy]propyl}pyridine (L 2) as viscous oils. Their proton and carbon-13 NMR spectra are characteristic. The L 2 shows signs of decay within few days. The complexes [PdCl2(L-I)](2) (1), [PtCl2(L-I)](2) (2), [HgBr2(L-I)] (3), [PdCl2(L-2)](2) (6), [PtCl2(L-2)](2) (7) and [(PdCl2)(3)(L-2)(2)](8) have been synthesized and found to give characteristic 1 H and 13 C NMR spectra. The 3 on crystallization from acetone:hexane (2: 1) mixture gives MeOC6H4HgBr (4) and [RTe+-HgBr2]Br- (R = -CH2CH2OCH2CHCH2-(2-(6-CH3-C5H3N))) (5). The crystals of 1, 2 and 4 are subjected to X-ray diffraction and their structures are solved. The I and 2 are 20-membered metallomacrocycles and do not dissociate in solution. The crystals of I and 2 have chloroform and benzene, respectively, in the lattice whereas 4 is a linear ArHgBr type species. The Pd/Pt in 1 and 2 has square planar geometry. The Pd-Te and Pd-N bond lengths in 1 are 2.530(1)/2.5313(9) and 2.097(4) and 2.101(4) angstrom, respectively.

Reactions of bis(N-phenylsalicylideneiminato)aluminium(III)di(mu-isopropoxo)di(isopro poxo) aluminium(III), [C6H4O{CH=N(C6H5)}](2)Al(mu-OPri)(2)Al(OPri)(2) (1) with simple and internally functionallized oximes in 1:1 and 1:2 molar ratios in refluxing anhydrous benzene yield binuclear complexes of the type, [C6H4O{CH=N(C6H5)}](2)Al(mu-OPri)(2)Al(ON=CRR')(OPri) and [C6H4O{CH=N(C6H5)}](2)Al(mu-OPri)(2)Al(ON-CRR')(2) [where R=R'=CH3; R=CH3, R=C4H3S-2, C4H3O-2 and C5H4N-2], respectively containing aluminium(III) atoms in six- and four-coordination sites. All these binuclear complexes are characterised by elemental analysis, molecular weight measurements and spectroscopy [IR and NMR(H-1, C-13 and Al-27)]. Reaction of bis(N-phenylsalicylideneiminato)(isopropoxo)aluminium(III) with 2-acetylthiophenyloxime in 1:1 molar ratio in refluxing anhydrous benzene, yields a novel heteroleptic compound, [C6H4O{CH=N(C6H5)}](2)Al{ON=C(CH3)C4H3S-2} (10). The crystal structure of [C6H4O {CH =N(C6H5)}](2)Al {ON =C(CH3)C4H3S-2} . CH2Cl2 shows five-coordination around the aluminium(III) atom.

Four amido-pyrrole cleft anion receptors bearing one or two ferrocene reporter groups have been synthesised and crystallographically characterised. The receptors contain either a non-conjugated (1 and 3) or conjugated (2 and 4) link between the anion binding amido-pyrrole unit and the ferrocene reporter groups. The anion binding affinities and electrochemical behaviour of the receptors in the absence and presence of anions have been studied by 1H NMR titration techniques and cyclic voltammetry using a Pt microdisc working electrode, respectively.

The reaction between Ph3SbBr2 and sodium salt of internally functionalized oximes in 1:2 molar ratio in refluxing anhydrous benzene afforded [Ph3Sb{ON=C(R)Ar}(2)] [R = CH3, Ar = C5H4N-2(1), C4H3S-2(2) C4H3O-2(3); R = H, Ar = C5H4N-2(4), C4H3S-2(5) and C4H3O-2(6)]. Treatment of (1) and (4) with 1 equiv. of Ph3SbBr2 yields the redistribution product [Ph3Sb(Br){ON=C(R)Ar}]. Controlled hydrolysis of (1) and (4) affords a species [Ph3Sb(OH){ON=C(R)Ar}]. All these complexes have been characterized by the elemental analyses, IR and NMR spectroscopic studies and in the case of I by single crystal X-ray diffraction studies. The structure of I features trigonal bipyramidal geometry around the antimony with the axial positions occupied by the two oxygen atoms of the oxime group [O(1)-Sb(1)-O(l)' 172.78(7)degrees] and equatorial positions by the phenyl groups.

Reactions between the bulky ligand tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) and HgX2 (X = Cl, Br, 1) in ethanol have been described. Complexes of stoichiometry (P:Hg) 1:1, 2:1 and 2:3 have been isolated and their spectral features discussed. The structures of the 1:1 bromide and iodide show them to be discrete monomers unlike most other tertiary phosphine analogues. Additionally a complex of stoichiometry TMPP(HgI2)(2) has been prepared and characterised structurally as (TMPP)HgI(mu-I)HgI(mu-I)(2)HgI(mu-I)HgI(TMPP).

yThe reactions of N-(2-chloroethyl)benzamide and N-[3-bromopropyl]phthalimide with ArTe- Na+ generated in situ by borohydride reduction of Ar2Te2, have resulted in N-[2-(4-methoxyphenyltelluro)ethyl]benzamide (L-1) and N-[2-(4-methoxyphenyltelluro)propyl] phthalimide (L-2) respectively. The L-1 and L-2 both exhibit characteristic H-1 and C-13 NMR spectra. The single crystal structures of L-1 and L-2, the latter as a mixed crystal with (LH2)-H-2 are determined by X-ray diffraction (XRD). The Te-C(alkyl) bond length is 2.140(8)/2.149(4) Angstrom and longer than Te-C(aryl), 2.107(8)/2.123(5) Angstrom. The complexes having stoichiometries [PdCl2(L-1)] (1), [PtCl2(L-1)](2), [(Phen)Pd(L-1)](ClO4)(2) (3), [(DPPE)Pd(L-1)](ClO4), (4) and [RuCl2(L-2)(2)] (5) were synthesized and characterized by elemental analyses, conductance and molecular weight measurements, NMR (H-1 and C-13) and FT-IR spectra. The deshielding of CH2Te ( similar to 0.2 ppm in H-1 NMR and up to 22 ppm in C-13{H-1} NMR) and NH signals (upto 0.8 ppm in H-1 NMR) of 1 -4, with respect to those of free L-1 indicates that L-1 coordinates with Pd-Pt(II) as a (Te, N) ligand. The CH2Te/CH2N signals in H-1 and C-13 NNIR spectra of 5 appear deshielded (0.8/0.14 and 20/8 ppm, respectively), when compared with those of free L2, indicating ligation of L-2 via Te and N.

Treatment of bis(dipbenylphosphino)methane disulfide (dppmS) or bis(diphenylphosphino)ethane disulfide (dppeS) with diiodine in dichloromethane yields the adducts dppmS .I-4 1 and dppeS .I-4 2, respectively, whose structures have been solved by X-ray crystallography. Compounds 1 and 2 consist of discrete molecular units containing bent P-S-I and linear S . . .I-I geometries that can be interpreted in terms of donation of electron density from sulfur to diiodine. Consistent with this interpretation, the P-S bonds are lengthened compared to the unco-ordinated phosphine sulfides, and the I-I bonds are lengthened compared to unco-ordinated diiodine. Both compounds can therefore be described as 'charge-transfer' complexes. The two S . . .I-I moieties in 1 are inequivalent having markedly different bond lengths and angles. In 2 both S . . .I-I moieties are identical. The structural features of 1 and 2 are in accordance with Raman and P-31 CP MAS NMR data.

Reactions of C2Cl3HgX (X = C2Cl3, Cl, Br) with the potential bidentate ligands, bis(diphenylphosphino)methane, 2,4'-bipyridyl, 4,4'-bipyridyl and 2,2'-dipyridyl disulfide(PySSPy), in a 2:1 molar ratio have been studied and the thermal and infrared spectral characteristics of the products have been examined. Complexes were isolated for (C2Cl3)(2)Hg and C2Cl3HgCl in all cases apart from between (C2Cl3)(2)Hg and the diphosphine. The diphosphine and 2,2'-dipyridyl disulfide formed 1:1 complexes (7, 6) with C2Cl3HgCl, whereas with (C2Cl3)(2)Hg the latter ligand formed [{(C2Cl3)(2)Hg}(2)(PySSPy)] (3) which on standing formed C2Cl3HgSPy (12). 4,4'-Bipyridyl and 2,4'-bipyridyl differed in the stoichiometry of the isolated complexes. (C2Cl3)(2)Hg formed 1:1 complexes (1, 2) with both ligands whereas C2Cl3HgCl formed a 1:1 complex (4) with the former ligand but a 1:2 complex (5) with the latter. All four ligands caused disproportionation of C2Cl3HgBr with resulting isolation of the mercury(II) bromide complexes (8-11). The structure of [(C2Cl3)(2)Hg (4,4'-bipyridyl)] (1) shows that only one nitrogen is weakly coordinated to mercury so that C-Hg-C is approximately linear in the monomeric structure but there are four intramolecular chlorines closer to mercury than the sum of the van der Waals radii. The C-Hg-S angle in [C2Cl3Hg(2-pyridyl thiolate)] (12) is only slightly distorted from linearity due to secondary bonding to nitrogen. There are two weak intramolecular contacts between mercury and chlorine and two intermolecular mercury-sulfur contacts to form pairs of molecules which form double chains along the b axis. [HgBr2(2,2'-dipyridyl disulfide)] (10) is polymeric and contains four-coordinate mercury with the ligand bridging between mercury atoms via coordination to nitrogen.

Reactions of HgX2 (X=Cl, Br, I) with the very bulky tertiary phosphine, tris(2,6-dimethoxyphenyl)phosphine (DMPP), in either a 1:1 or a 1:2 ratio, result in only the isolation of the 1:1 adducts. The structures adopted in the solid state are markedly influenced by the steric requirement of the phosphine. In contrast to the 1:1 triphenylphosphine adducts reported earlier, which are dimeric, the DMPP mercury(II) chloride and bromide complexes are weakly linked dimers while the iodide is the first example of a mercury iodide–phosphine complex with a monomeric distorted trigonal-planar arrangement around mercury. All three complexes contain secondary interactions with the o-methoxy groups.