Heather L. Milton

N-Metallation of MS2N2 rings. X-ray crystal structures of [(η5-C5Me5)Ir(S2N2)Au(PPh3)][ClO4], [{(η5-C5Me5)Ir(S2N2)Au}2(μ2-dppm)][ClO4]2 and [Au(dppeS-P)Cl]2

Bimetallic complexes [(η5-C5R5)M(S2N2)Au(PPh3)][ClO4] and tetrametallic species [{(η5-C5R5)M(S2N2)Au}2(μ2-P^P)][ClO4]2 (R=H, M=Co; R=Me, M=Ir; P^P=dppm or dppe) can be prepared by treatment of [(η5-C5R5)M(S2N2)] with gold(I) electrophiles generated by chloride abstraction from [AuCl(PPh3)] or [(AuCl)2(μ2-P^P)]. X-Ray crystallography of [(η5-C5Me5)Ir(S2N2)Au(PPh3)][ClO4] and [{(η5-C5Me5)Ir(S2N2)Au}2(μ2-dppm)][ClO4]2 confirms auration of the metal-bound nitrogen atom of the MS2N2 ring. π-Stacking of theMS2N2 rings occurs within both structures.

Synthesis and characterisation of cyanodithioimidocarbonate [C2N2S2]2− complexes

[PPh4]2[M(C2N2S2)2](M = Pt, Pd) and [Pt(C2N2S2)(PR3)2](PR3= PMe2Ph, PPh3) and [Pt(C2N2S2)(PP)](PP = dppe, dppm, dppf) were all obtained by the reaction of the appropriate metal halide containing complex with potassium cyanodithioimidocarbonate. The dimeric cyanodithioimidocarbonate complexes [[Pt(C2N2S2)(PR3)]2](PR3 = PMe2Ph), [M[(C2N2S2)(eta5-C5Me5)]2](M = Rh, Ir)and [[Ru(C2N2S2)(eta6-p-MeC6H4iPr)]2] have been synthesised from the appropriate transition metal dimer starting material. The cyanodithioimidocarbonate ligand is S,S and bidentate in the monomeric complexes with the terminal CN group being approximately coplanar with the CS2 group and trigonal at nitrogen thus reducing the planar symmetry of the ligand. In the dimeric compound one of the sulfur atoms bridges two metal atoms with the core exhibiting a cubane-like geometry.

Synthesis and structure of [Fc(RO)PS2]− complexes

Reaction of An(S)PS(2)P(S)An with NaOR [R = Me, Et, (i)Pr] gives the non-symmetric phosphonodithioato anions [An(RO)PS(2)](-) which can be complexed to a range of metals. The group 10 metals (Ni, Pd and Pt) adopt square planar ML(2) complexes. The zinc and cadmium complexes adopt isostructural dimeric M(2)L(4) structures whilst mercury complexes adopt a subtly different dimeric motif. Two distinctly different lead complexes are reported, one consisting of PbL(2) units joined by Pb...S interactions to form distinct dimeric pairs, the other being a completely new structural motif for complexes of this type, PbL(2) units held together by covalently bonded bridging ligands to form an infinite polymeric chain structure. All new compounds have been characterised spectroscopically and nine demonstrative X-ray structures are reported.

SYNTHESIS AND COORDINATION OF 2-(DIIPHENYLPHOSPHINO)PICOLINAMIDE

The ligand 2-(diphenylphosphino)picolinamide (dpppa) is readily prepared by addition of a thf solution of Ph2PCl to a thf solution of picolinamide and Et3N, followed by overnight reflux. The chalcogen derivatives are easily prepared on reaction with H2O2, S or Se, for the oxide, sulfide, and selenide respectively. Reaction of dpppa with [MCl2(cod)] (M = Pt or Pd), [{MCl(μ-Cl)(η-C5Me5)}2] (M = Rh or Ir), [{RuCl(μ-Cl)(pCymene)}2], [{Pd(μ-Cl)(η-C3H6)}2], [{Pd(μ-Cl)(C10H6NO)}2], [{Pd(μCl)(C9H12N)}2], [{Pd(μ-Cl)(C12H12N)}2], [{PtCl(μ-Cl)(PR3)}2] (PR3 = PMe2Ph or PEt3) generates the corresponding monodentate complexes. Further reaction of the monodentate complexes with AgBF4 or NaOtBu provide N and O bound bidentate complexes respectively (Scheme 1).

SYNTHESIS OF TITANOCENE COMPLEXES USING POLYAROMATIC LIGANDS CONTAINING A DISULFIDE BRIDGE

The complexes Cp2Ti[S2X] (Cp = cyclopentadienyl), where S2X is a polyaromatic dithiolate ligand, are readily prepared by addition of the appropriate ligand to Cp2Ti(CO)2. The resulting complexes have the Cp2Ti unit inserted into the sulfur sulfur bond. A number of novel complexes have been prepared using a series of naphthalene based and biphenyl based ligands, the simplest examples in each case being naphtho[1,8-cd]-1,2-dithiole 1 and dibenzo[ce]-1,2-dithiine 2.

CRYSTALLOGRAPHIC SUDIES OF CHALCOGEN BRIDGED NAPHTHALENES

Peri-bridged naphthalenes are flat molecules that exhibit π -stacking in the solid state. It is possible for the π -stacking in sulfur bridged naphthalenes to be disrupted by attaching oxygen atoms to the sulfur bridges. The crystal structure of naphtho[1,8-cd][1,2]diselenole (1) shows significant π -stacking interactions. X-ray crystal structures of molecules 1–4 were determined, and the structure of (1) shows that this is also the case for the S analogue. Crystal structures of molecules 2–4 also show some π -stacking, but it is disrupted to varying degrees by the oxygen atoms.

Hydrothermal syntheses and crystal structures of three zinc succinates: Zn(C4H4O4)-α, Zn(C4H4O4)-β and K2Zn(C4H4O4)2

Three zinc succinate coordination polymers have been synthesised hydrothermally. Two polymorphs of Zn(C4H4O4) adopt three-dimensional structures consisting of tetrahedral Zn atoms isolated from each other via bis-bidentate succinate moieties. The polymorphs differ in the conformation of the succinate group, the α form (I) having syn-periplanar geometry whereas the β form (II) has anti-periplanar geometry. K2Zn(C4H4O4)2 (III) has a layered structure also composed of isolated tetrahedral Zn units. In this case the two crystallographically distinct succinate groups, one of each conformer, have bis-monodentate coordination, acting as both inter- and intra-layer bridges between neighbouring Zn-containing layers. The ‘double’ zinc succinate layers are separated along the b-axis by inter-layer potassium ions.

RING OPENING OF FERROCENYL LAWESSONS AND WOOLLINS REAGENTS; SYNTHESIS OF NOVEL PHOSPHONODITHIOATO AND PHOSPHONODISELENOATO METAL COMPLEXES

There is a great deal of literature available detailing the synthesis, chemistry, and structural studies of the complexes of (1) and (3) ligands.1 The same cannot be said for compounds of (2). Aragoni et al. have reported several monomeric structures involving two organodithiophosphonate ligands attached to a metal center (Ni2+, Pd2+, and Pt2+) in a square planar conformation. They have achieved this via a ring opening reaction of the well known thionation compound Lawessons Reagent.2 Here we report the synthesis of phosphonodithioate ligands and phosphodiselenoate ligands by the ring opening of Ferrocenyl Lawessons and Woollins reagents respectively. Reactions of these ligands were carried out with a variety of metal (2+) salts of the form MX2 (where M = Ni, Pd, Pt, Cd, Zn, Hg, Pb, and Sn) forming metal complexes exhibiting a number of different structural motifs including square planar monomers, dimers, and even polymeric structures.