Colin J. Burchell

Ethane-1,2-diphosphonic acid as a building block in supramolecular chemistry; a pillared-layer framework and framework-encapsulated cations

The 1:1 adduct of piperazine and ethane-1,2-diphosphonic acid is a salt [C(4)H(12)N(2)](2+).[C(2)H(6)O(6)P(2)](2-), in which both ions lie across centres of inversion in space group P2(1)/c. The anions are linked by a single type of O-H...O hydrogen bond [O...O, 2.562 (3) A; H...O, 1.73 A, O-H...O, 169 degrees ] into (6, 3) nets built from a single type of R(4)(4)(22) ring. The cations lie between these nets, linked to them by two types of N-H...O hydrogen bond [N...O, 2.635 (3) and 2.735 (3) A; H...O 1.72 and 1.82 A, N-H...O, 175 and 177 degrees ] such that the cations link adjacent sheets, thus forming a pillared-layer framework. The aquated adduct formed between trimethylenedipiperidine and ethane-1,2-diphosphonic acid is also a salt [C(13)H(28)N(2)](2+).[C(2)H(6)O(6)P(2)](2-).2.8[H(2)O], in which there are 12 different types of hydrogen bond, eight O-H...O and four N-H...O. The anions are linked into chains by pairs of O-H...O hydrogen bonds and these chains are linked by the water molecules into a continuous three-dimensional framework. Within the anion/water framework are large voids which contain pairs of cations, linked to the framework by N-H...O hydrogen bonds.

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.

Adducts of meso and racemic 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane with trigonally trisubstituted benzene carboxylic acids: supramolecular structures in one and two ­dimensions

The meso and racemic forms of 5,5,7,12,12,14-hexamethyl-1,4,8, 11-tetraazacyclotetradecane, C(16)H(36)N(4) (tet-a and tet-b, respectively), form adducts with trigonally trisubstituted benzene carboxylic acids; tet-a-3,5-dinitrobenzoic acid (1/2) (1), tet-a-5-hydroxyisophthalic acid-water (1/1/1) (3) and tet-b-5-hydroxyisophthalic acid-water (1/1/1) (4) are all salts, [C(16)H(38)N(4)](2+).2[C(7)H(3)N(2)O(6)](-) (1) and [C(16)H(38)N(4)](2+).[C(8)H(4)O(5)](2-).H(2)O (3) and (4). The conformations of the [(tet-a)H(2)](2+) and [(tet-b)H(2)](2+) cations are entirely different: [(tet-a)H(2)](2+) is precisely centrosymmetric in (1) and approximately so in (3), while [(tet-b)H(2)](2+) has approximate C(2) symmetry in (4). In each salt the cation forms two intramolecular N-H.N and four intermolecular N-H.O hydrogen bonds. In (1) the supramolecular structure is one-dimensional, a C(2)(2)(13)[R(2)(4)(16)] chain of rings. Compounds (3) and (4) crystallize in space groups P2(1)2(1)2(1) and P2(1)/c, respectively, but the supramolecular structures are very similar: in each, the anions and the water molecules form a C(7)[R(3)(3)(13)] chain of rings, generated in (3) by a 2(1) axis and in (4) by a glide plane. These chains are linked, in both (3) and (4), by cations to form sheets. Adjacent meso cations in (3) are related by a 2(1) axis and adjacent chiral cations in (4) are related by a glide plane.

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.

THE SYNTHESIS OF TRISELENOCARBONATE COMPLEXES OF PLATINUM

The addition of dichloromethane solutions of carbon diselenide to liquid ammonia containing suspensions of platinum bis-phosphine dichlorides [PtCl2(PRX)n] (n = 2, (PRX) = PMe3, PMe2Ph, PMePh2, and PPh3, n = 1, (PRX) = dppm, dppe, dppp, dppf) gives, after evaporation of the ammonia and extraction of the reaction residues with dichloromethane, the appropriate platinum bis-phosphine triselenocarbonate complexes in reasonable yields (40–60%).

Hydrogen-bonded sheets in the 1:1 salt of tet-b and trimesic acid

Tet-b (racemic 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, C(16)H(36)N(4)) and trimesic acid (1,3,5-benzenetricarboxylic acid, C(9)H(6)O(6)) form a salt partially solvated by both water and methanol, i.e. 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1,3,5-benzenetricarboxylic acid--methanol--water (1/1/0.78/1.12), C(16)H(38)N(4)(2+) x C(9)H(4)O(6)(2-) x 0.78CH(4)O x 1.12H(2)O. The anions are linked by O--H...O hydrogen bonds [O...O 2.442 (4) and 2.458 (4) A; O--H...O 170 and 171 degrees ] into zigzag chains; orientationally disordered cations are linked to the anion chains by means of N--H...O hydrogen bonds [major orientation: N...O 2.695 (3)--3.071 (4) A, N--H...O 148--179 degrees; minor orientation: N...O 2.75 (2)--3.34 (2) A, N--H...O 147--170 degrees ] and link the chains into sheets. The solvent molecules are all disordered, but appear to play no significant structural role apart from space filling.

THE CHEMISTRY OF (ECN)2 (E = S, Se) AND RELATED COMPOUNDS

The psuedohalogens (ECN)2 (E = S, Se) have been prepared by reaction of AgNCS with bromine and AgNCSe with iodine respectively. (SCN)2 spontaneously polymerises to give polythiocyanogen a polymer of unknown structure with empirical formula (SCN)x. A series of late transition metal complexes bearing the ambidentate psuedohalide ligands (ECN) (E = S, Se) have been synthesised. In addition we have prepared a series of late transition metal complexes of the cyanodithioimidocarbonate ion [C2N2S2]2− and the first transition metal complexes of the cyanodiselenocarbonate ion [C2N2Se2]2−.

A three-dimensional hydrogen-bonded framework in 4,4′-tri­methyl­ene­di­piperidinium–2,5-di­carboxy­benzene-1,4-di­carboxyl­ate–water (1/1/1)

The title compound is a salt, C13H28(N2)(2+).C10H4(O8)(2-).H2O. In the anion, there are two short intramolecular hydrogen bonds [O.O 2.395 (2) and 2.383 (2) A; O.H.O 175 and 172 degrees]. Pairs of anions and pairs of water molecules are linked by further O-H.O hydrogen bonds [O.O 2.756 (2) and 2.980 (2) A; O-H.O 171 and 175 degrees] into cyclic centrosymmetric R(6)(6)(16) aggregates; these aggregates are linked via the cations into a three-dimensional framework by means of four distinct N-H...O hydrogen bonds [N...O 2.787 (2)-3.204 (2) A; N-H...O 148-173 degrees].

A hydrogen-bonded adduct containing seven-component supramolecular aggregates

The title compound is a salt, 3,6,9,16,19,22-hexaazatricyclo[22.2.2.2(11,14)]triaconta-1(26),11(29),12,14(30),24,27-hexaene-3,5-dinitrobenzoic acid-methanol (1/4/2), C24H42N6(4+).4C7H3N2(O6)(-).2CH4O, in which the cation lies across a centre of inversion and one of the two independent anions is positionally disordered over two sets of atom sites having equal occupancy. The components are linked by four types of N-H...O hydrogen bond [N...O 2.674 (2)-2.815 (2) A; N-H.O 149-163 degrees] and one type of O-H...O hydrogen bond in which the acceptor is disordered over two closely adjacent sites [O...O 2.67 (4) and 2.75 (4) A; O-H...O 172 and 173 degrees], forming centrosymmetric seven-component aggregates.