Three-dimensional frameworks built from piperazine-2,5-dione and simple metal salts (M = Co, Ni, Cu and Ag).

Compounds trans-tetraaquadichloridocobalt(II)-piperazine-2,5-dione (1/1), [CoCl(2)(H(2)O)(4)].C(4)H(6)N(2)O(2), (I), and trans-tetraaquadichloridonickel(II)-piperazine-2,5-dione (1/1), [NiCl(2)(H(2)O)(4)].C(4)H(6)N(2)O(2), (II), are isomorphous. In each structure, the metal complex and the piperazinedione unit both lie across centres of inversion in the space group P2(1)/n. The [MCl(2)(H(2)O)(4)] units (M = Co or Ni) are linked by O-H...Cl hydrogen bonds into sheets of R(2)(2)(8) and R(4)(2)(12) rings, and these sheets are linked by the piperazinedione components via a combination of O-H...O and N-H...Cl hydrogen bonds into a three-dimensional framework. In catena-poly[[[trans-diaquacopper(II)]-di-mu-chlorido] piperazine-2,5-dione solvate], {[CuCl(2)(H(2)O)(2)].C(4)H(6)N(2)O(2)}(n), (III), the metal ion and the piperazine unit both lie across centres of inversion in the space group I2/a. The coordination polymer forms chains of centrosymmetric [CuCl(2)(H(2)O)(2)] units running parallel to [010] and these are linked by the piperazinedione units into a three-dimensional framework structure. In poly[mu(3)-nitrato-mu(2)-piperazine-2,5-dione-silver(I)], [Ag(NO(3))(C(4)H(6)N(2)O(2))](n), (IV), the silver and nitrate ions lie on mirror planes in the space group Pnma, while the piperazinedione unit lies across a centre of inversion. The compound is a coordination polymer containing five-coordinate approximately square-pyramidal Ag, in which the ligating O atoms are derived from three different nitrate ligands and two different piperazinedione ligands. The ionic components form sheets in which each anion is coordinated to three different cations, and these sheets are linked into a three-dimensional framework by the organic ligands, each of which coordinates to two different Ag centres. The significance of this study lies in its demonstration of a wide variety of framework types built from a common and very simple organic component with simple metal salts.

Sheets built from C-H...O and C-H...pi(arene) hydrogen bonds in (2RS,6SR)-N-diphenylacetyl-2,6-diphenylpiperidin-4-one and (2RS,3SR,5RS,6SR)-3,5-dimethyl-N-phenylacetyl-2,6-diphenylpiperidin-4-one.

In (2RS,6SR)-N-diphenylacetyl-2,6-diphenylpiperidin-4-one, C31H27NO2, (I), the piperidinone ring adopts an almost ideal twist-boat conformation, and the molecules are linked into sheets by a combination of one C-H...O hydrogen bond and one C-H...pi(arene) hydrogen bond. (2RS,3SR,5RS,6SR)-3,5-Dimethyl-2,6-diphenyl-N-phenylacetylpiperidin-4-one, C27H27NO2, (II), crystallizes with Z' = 2 in the space group P-1; the piperidinone rings adopt an almost ideal boat conformation in one of the molecules and a conformation between boat and twist-boat in the other. The molecules of (II) are linked into sheets by a combination of five C-H...O hydrogen bonds and one C-H...pi(arene) hydrogen bond.

Hydrogen-bonded sheets in racemic cis-(2,2'-bipyridyl-kappa2N,N')oxo(pentane-2,4-dionato-kappa2O,O')(thiocyanato-kappaN)vanadium(IV).

The title compound, [V(C5H7O2)(NCS)O(C10H8N2)], crystallizes with Z' = 2 in the space group Pbca. The molecules are linked into sheets by a combination of four C-H...O hydrogen bonds and one C-H...N hydrogen bond. The four C-H...O hydrogen bonds generate chains of rings, where each chain contains just a single enantiomer of each of the two independent molecules, while the C-H...N hydrogen bond generates a chain containing both enantiomers of just one of the independent molecules.

Racemic cis-methoxobis(2-methyl-3-oxo-4H-pyran-4-olato)oxovanadium(V) redetermined at 120 K: hydrogen-bonded ribbons containing R2/2(7), R2/2(14) and R4/4(18) rings.

In the title compound, [V(CH3O)(C6H5O3)2O], the V-O bond lengths to the oxo and methoxo ligands are 1.593 (3) and 1.768 (3) A, respectively, at 120 K; the V-O bond lengths trans to these two ligands are 2.246 (3) and 2.116 (3) A. Molecules are linked by three C-H...O hydrogen bonds into complex ribbons containing three types of ring.

2-(2-Pyridyl)pyridinium perchlorate, redetermined at 120 K: complex hydrogen-bonded sheets.

In the title compound, C10H9N2+.ClO4-, the ions are linked into complex sheets by the combination of one N-H...O and four independent C-H...O hydrogen bonds.

Di-mu-halogeno-bis[halogeno(triphenylphosphine)mercury(II)], [Ph3PHgX(mu-X)2XHgPPh3], reinvestigated at 120 K for X = Cl and Br, and a second polymorph for X = I, also at 120 K.

Di-mu-chloro-bis[chloro(triphenylphosphine)mercury(II)], [Hg2Cl4(C18H15P)2], (I), and di-mu-bromo-bis[bromo(triphenylphosphine)mercury(II)], [Hg2Br4(C18H15P)2], (II), have been reinvestigated at 120 K. The molecules of (I) lie across inversion centres in space group P2(1)/n, and in both (I) and (II) the complexes are linked into three-dimensional frameworks by a combination of C-H...X (X = Cl and Br) and C-H...pi(arene) hydrogen bonds. At 120 K, di-mu-iodo-bis[iodo(triphenylphosphine)mercury(II)], [Hg2I4(C18H15P)2], (III), crystallizes as a new polymorphic form having Z' = 1/2, where the complexes lie across inversion centres in space group P2(1)/n; the complexes are linked into sheets by a combination of C-H...I and C-H...pi(arene) hydrogen bonds. In the Z' = 1 polymorph of this compound, a single C-H...I hydrogen bond generates simple chains.

Piperazine-2,5-dione-oxalic acid-water (1/1/2) and a redetermination of piperazine-2,5-dione, both at 120 K: hydrogen-bonded sheets containing multiple ring types.

In piperazine-2,5-dione-oxalic acid-water (1/1/2), C4H6N2O2.C2H2O4.2H2O, both organic components lie across inversion centres in space group P-1. The molecules are linked by N-H...O and by both two-centre O-H...O and three-centre O-H...(O)2 hydrogen bonds into sheets built from R(1)(2)(5), R(2)(2)(8), R(4)(4)(8) and R(5)(4)(15) rings. In piperazine-2,5-dione, C4H6N2O2, where the molecules lie across centres of inversion in space group P2(1)/c, the molecules are linked by paired N-H...O hydrogen bonds into ribbons of centrosymmetric R(2)(2)(8) rings, which are further linked into sheets by C-H...O hydrogen bonds, generating R(4)(3)(14) rings between the ribbons.

Orthorhombic and monoclinic polymorphs of 1,3,5-triphenylperhydro-1,3,5-triazine-2,4,6-trione at 120 K: chains and sheets formed by C-H...pi(arene) hydrogen bonds.

The title compound, C21H15N3O3, crystallizes in two polymorphic forms. In the orthorhombic polymorph, (I), in space group Fdd2 with Z' = 1, the molecules lie in general positions, while in the monoclinic polymorph, (II), in space group C2/c with Z' = 1/2, the molecules lie across twofold rotation axes. In each polymorph, the molecules are linked by a single C-H.pi(arene) hydrogen bond, forming chains in polymorph (I) and sheets in (II).

Partially oxidized [2-[(benzoylmethylene)diphenyl-lambda5-phosphino]ethyl]diphenylphosphine as a monohydrate.

The title compound is a co-crystal of [2-[(benzoylmethylene)diphenyl-lambda5-phosphino]ethyl]diphenylphosphine oxide, [2-[(benzoylmethylene)diphenyl-lambda5-phosphino]ethyl]diphenylphosphine and water in an approximate 2:1:3 ratio, with an overall composition of C34H30O1.678P2.H2O. The ylidic portion shows the expected electronic polarization, and the organic components are linked by a combination of C-H...O and C-H...pi(arene) hydrogen bonds.

Micro-ethane-1,2-diylbis(diphenylphosphine oxide)-kappa(2)O:O'-bis[dibenzyldichlorotin(IV)]: a centrosymmetric complex containing trigonal-bipyramidal tin(IV), linked into chains of rings by C-H.pi(arene) hydrogen bonds.

The title compound, [Sn(2)Cl(4)(C(7)H(7))(4)(C(26)H(24)O(2)P(2))], (I), was isolated from the reaction of 1,2-bis(diphenylphosphino)ethane with dibenzyltin(IV) dichloride in the presence of air. The molecules of (I) lie across centres of inversion in space group C2/c and contain five-coordinate Sn atoms. The molecules are linked into chains of rings by a single C-H.pi(arene) hydrogen bond.

6,6'-dimethoxy-2,2'-[(1R,2R)-cyclohexane-1,2-diylbis(nitrilomethylidyne)]diphenol: three C-H...O hydrogen bonds generate a three-dimensional framework.

Molecules of the title compound, alternatively called (R,R)-N,N'-bis(3-methoxysalicylidene)-trans-cyclohexane-1,2-diamine, C(22)H(26)N(2)O(4), contain two intramolecular O-H.N hydrogen bonds and adopt a conformation with approximate twofold rotational symmetry. The molecules are linked by three C-H.O hydrogen bonds [H.O = 2.45-2.55 A, C.O = 3.329 (2)-3.398 (2) A and C-H.O = 142-172 degrees ] into a continuous framework.