Structure of the anti-cancer drug complex tetrakis (mu-acetato)-bis(1-methyladenosine)dirhodium(II) monohydrate.

[Rh2(C2H3O2)4(C11H16N5O4)2].H2O, Mr = 1024.6, triclinic, P1, a = 7.808 (3), b = 11.469 (4), c = 12.091 (2) A, alpha = 69.55 (2), beta = 79.46 (2), gamma = 76.61 (3) degrees, V = 980.7 (6) A3, Z = 1, Dx = 1.735 g cm-3, lambda (Cu K alpha) = 1.5418 A, mu = 77.6 cm-1, F(000) = 522, room temperature, R = 0.053 for 3638 unique reflections. Structure consists of two rhodium(II) ions in a metal--metal bond bridged by four acetate groups. The remaining axial coordination sites on the rhodium ions are coordinated to the N(7) positions of two 1-methyladenosine molecules.

Structures of the monohydrate and dihydrate of (bidentate pyrophosphato) trans-diammine cis-diaqua chromium (III).

(OC-6-32)-Diamminediaqua [pyrophosphato(3-)]chromium(III) monohydrate, [Cr(NH3)2-(H2O)2(HP2O7)]. H2O, Mr = 315.1, triclinic, P1, a = 7.127 (2), b = 8.390 (2), c = 9.619 (2) A, alpha = 72.14 (2), beta = 98.86 (2), gamma = 76.98 (3) degrees, V = 517.7 (3) A3, Z = 2, Dx = 2.02 g cm-3, lambda(Cu K alpha) = 1.5418 A, mu = 129 cm-1, F(000) = 322, T = 293 K. (OC-6-32)-Diamminediaqua[pyrophosphato(3-)]-chromium(III) dihydrate, 0.5( [Cr(NH3)2(H2O)2-(HP2O7)].2H2O), Mr = 0.5(333.1), monoclinic, C2/m, a = 13.118 (3), b = 12.101 (3), c = 7.436 (2) A, beta = 105.09 (2) degrees, V = 1139.7 (3) A3, Z = 8, Dx = 1.94 g cm-3, lambda(Cu K alpha) = 1.5418 A, mu = 118 cm-1, F(000) = 684, T = 293 K. The structures were solved by the multi-solution technique and refined by the method of least squares to yield a final R index of 0.057 for 986 reflections in the monohydrate and a final R index of 0.043 for 1030 reflections in the dihydrate. The six-membered chromium pyrophosphate chelate ring is in a boat conformation for the monohydrate with an intramolecular hydrogen bond between an ammonia proton and a pyrophosphate O atom. In the dihydrate, the chelate ring is bisected by the mirror plane resulting in an unusual planar chelate ring conformation which does not permit intramolecular hydrogen bonding.

Structures of the meridional and facial isomers of triamminechromium pyrophosphate dihydrate.

The meridional and facial isomers of triamminechromium pyrophosphate were separated by chromatography on Dowex-50-H+, and crystallized as isoionic species. The meridional isomer crystallized as a monomer [Cr(HP2O7)(NH3)3(H2O)].2H2O but the facial isomer crystallized as a centrosymmetric dimer of [Cr(HP2O7)(NH3)3]. 2H2O, in which the remaining water in the coordination sphere of each chromium is replaced by a phosphate oxygen from the other monomer unit. Meridional isomer: monoaquatriammine(pyrophosphato)chromium(III) dihydrate, Mr = 332.1, monoclinic, P21/c, a = 7.825 (2), b = 10.107 (3), c = 15.322 (5) A, beta = 103.92 (5) degrees, V = 1176 (1) A 3, Z = 4, Dx = 1.875 g cm-3 lambda(Mo K alpha) = 0.71073 A, mu = 12.6 cm-1, F(000) = 684, final R = 0.050 for 1828 reflections. The most notable difference between this compound and the corresponding tetraammine complex reported previously is a significant shortening of the metal-ligand bond lengths not only for the water ligand but also for the ammonia ligands. The dimer: mu-(pyrophosphato-O,O',O")-bis[triamminechromium(III)] dihydrate, Mr = 314.0, monoclinic, P21/c, a = 8.695 (2), b = 10.327 (3), c = 11.913 (4) A, beta = 97.81 (5) degrees, V = 1060 (1) A3, Z = 4, Dx = 1.969 g cm-3, lambda(Cu K alpha) = 1.5418 A, mu = 125.7 cm-1, F(000) = 644, final R = 0.047 for 1389 reflections. This structure, which sits on a center of inversion, forms a tricyclic complex involving two Cr atoms. The structure is characterized by reciprocal coordination between the metal ions and anionic O atoms of the pyrophosphate moieties.(ABSTRACT TRUNCATED AT 250 WORDS)

The crystal structure of diazomethyl beta-D-galactopyranosyl ketone.

The title compound (C8H12N2O6) crystallizes in the orthorhombic space group P2(1)2(1)2(1) (Z = 4), with a = 4.871(1), b = 11.136(2), c = 18.301(2) A. The structure was solved by the multi-solution technique and refined by full-matrix least-squares to a final R-index of 0.042. The compound adopts the 4C1(D) conformation. Bond lengths in the diazoacetyl group are consistent with the presence of a zwitterion.

Structural and biochemical properties of bidentate tetraaquarhodium(III) complexes of inorganic pyrophosphate and adenosine 5'-diphosphate.

The structural and biochemical properties of the alpha,beta-bidentate tetraaquarhodium(III) complexes of inorganic pyrophosphate [Rh(H2O)4PP] and adenosine diphosphate [Rh(H2O)4ADP] are examined. These Rh(III) complexes are exchange-inert analogues of the corresponding physiologically important MgIIPP and MgIIADP complexes. The crystal structure of [Rh(H2O)4H2P2O7]+Cl- shows that the six-membered chelate ring adopts a twist-boat conformation with an unusually high puckering amplitude of 0.756 (3) A. The Rh coordination distances average 2.02 (1) A, while the bridge P-O bonds are virtually equal in length. All 10 protons of the complex participate in hydrogen bonding. There are two intramolecular hydrogen bonds between the phosphate oxygen atoms and the axially coordinated water molecules. The Rh(H2O)4PP complex was found to be a substrate for yeast inorganic pyrophosphatase, with Ki = 0.063 (7) mM and Vm = 500 (100) min-1. The two screw sense isomers of Rh(H2O)4ADP were prepared from (Rp)-[alpha-16O,18O]ADP and assigned configuration on the basis of the magnitude of their 31P NMR isotopic chemical shifts. The Rh(H2O)4ADP complex binds a number of kinases as tightly as MgADP. Arginine kinase and creatine kinase were shown to bind the delta Rh(H2O)4ADP isomer 7 and 45 times tighter, respectively, than the lambda isomer. The reactivity of Rh(H2O)4PP with pyrophosphatase is comparable to that of Cr(H2O)4PP, and the binding affinities of the Rh(H2O)4ADP screw sense isomers for kinases are also comparable to those observed for the corresponding Cr(H2O)4ADP screw sense isomers.

Mechanistic studies on metal-pyrophosphate hydrolysis. Structure of tetraammine(chloroaquo)cobalt (III) dichloride ([Co(NH3)4ClH2O]2+.2Cl-), an acid hydrolysis product of Co(NH3)4HP2O7 and Co(NH3)4PO4.

The octahedral complex tetraammine(chloroaquo)cobalt(III) dichloride is shown to be the HCl hydrolysis product of both P1,2-bidentate tetraammine(pyrophosphato)cobalt(III) [Co(NH3)4HP2O7 or CoPP] and bidentate tetraammine(phosphato)cobalt(III) [Co(NH3)4PO4 or CoP]. The complex crystallizes in the orthorhombic space group Pna21 with cell dimensions a = 13.033(2)A, b = 6.710(1)A, and c = 10.318(2)A; the crystal structure was refined to a final disagreement index of 0.033. The average of the four Co-N distances is 1.944 +/- 6A. The Co-Cl distance is 2.257(2)A and the Co-O(W) distance is 1.971(4)A. Both protons of the coordinated water molecule are engaged in strong hydrogen bonds to the two nonbonded chloride counterions with O(W)-Cl distances of 3.087(6)A and 3.123(6)A. Each nonbonded chloride is engaged in seven hydrogen bonding interactions resulting from the high ratio of hydrogen bond donors to acceptors in the CoP structure. Cobalt bisphosphate (CoP2) is the final enzyme hydrolysis product when CoPP is used as substrate in the yeast inorganic pyrophosphatase reaction. The bridge oxygen atom is the site of initial CoPP cleavage both for HCl catalyzed hydrolysis as well as for enzyme catalyzed hydrolysis.

X-ray crystallographic and nuclear magnetic resonance spectral studies of the products from the yeast inorganic pyrophosphatase-Co(NH3)4PP reaction. Investigation of the pyrophosphatase reaction mechanism.

Yeast inorganic pyrophosphatase catalyzes the hydrolysis of P1,P2-bidentate Co(NH3)4 pyrophosphate [Co(NH3)4PP] to the cis, bis(phosphate) complex Co(NH3)4(Pi)2, which is not stable at neutral pH and over a period of 24 h converts to HPO4(2-) and a mixture of bidentate Co(NH3)4(PO4) and monodentate Co(NH3)4(H2O)(HPO4). Concurrent with this process is the reduction and subsequent release of Co(H2O)6(2+) from the cobalt tetraammine bis(phosphate) complex and/or the cobalt tetraammine monophosphate complex. Bidentate tetraammine phosphatocobalt (III), hexaaquocobalt(II), orthophosphate, and two free water molecules cocrystallize [Co(NH3)4PO4 . Co(H2O)6(2+) . HPO4(2-) . 2H2O] from the reaction mixture in the triclinic space group Pi (Z = 2) with cell dimensions a = 6.849 (1) A, b = 11.693 (2) A, c = 12.630 (2) A, alpha = 65.60 (1) degree, beta = 88.98 (1) degree, and gamma = 73.04 (1) degree. The structure was solved by the heavy atom technique and refined to an R index of 0.040 by using 3077 intensities measured up to a 2 theta limit of 155 degrees. 31P NMR studies of the equilibrium mixture reveal that the equilibrium constant is a sensitive function of solution pH and temperature. Unlike the Co(NH3)4PP complex, there is evidence indicating that the Mg(H2O)4PP complex is degraded to monodentate Mg(H2-O)5PO4 in the enzyme active site.