Synthesis and molecular structure of bis(6-mercapto-9-benzylpurine)palladium(II)-dimethylacetamide

Abstract

Bis(6-mercapto-9-benzylpurine)palladium(II) Table VIII. Rigid Group Angular Parameters Compd , deg a, deg 9, deg (C6Hs),Sna-f 7.1Registry No. (C6Fs)4Sn, 106549-2; (C6Fs)4Ge, 1452-12-6. Supplementary Material Available. A listing of structure factor amplitudes (Tables I and II) will appear following these pages in the microfilm edition of this volume of the journal. Photocopies of the supplementary material from this paper only or microfiche (105 X 148 mm, 24X reduction, negatives) containing all of the supplementary material for the papers in this issue may be obtained from the Journals Department,

Copper tetrafluoroborate complexes of the potentially binucleating ligand 1,4-di(2′-pyridyl)aminophthalazine. Mononuclear and polynuclear derivatives

“…The location of a proton on N(4) or N(6) cannot be obtained directly from the crystal structures of I or 11, however. The C(14)-N(6t C(18) angles of 120.2(13)" in I and 119.4(13)" in PI fall between 125 k 3", for protonated nitrogen atoms, and 116 f 3", for unprotonated nitrogen atoms, as suggested by the empirical rule of Singh (26,27) for six-membered nitrogen heterocycles. One possible explanation for this observation of a value lying between 125" and 116" is that the site of protonation is disordered between N(4) and N(6).…”

[(Glycylglycinato)(cytosine)copper(II)]. A model for enzyme–metal–nucleic acid ternary complexes

“…The bond lengths and angles in the cytosine ligand are, in general, in reasonable agreement with other determinations (Sundaralingam & Carrabine, 1971;Szalda et al, 1975b). (b) The glycylglycine chelate ligand As we have noted previously (Marzilli, Kistenmacher & Chang, 1973;Marzilli et al, 1974;Kistenmacher et al, 1975b), there is considerable dissymmetry in the exocyclic bond angles at the hetero atom to which the metal atom is bonded in transition-metal purine complexes where interligand hydrogen bonding or chelation [see, for example, Heitner & Lippard (1974)] takes place. The present structure also shows this feature, Cu-N(3)-C(2) 110.3 (3) ° and Cu-N(3)-C(4) 127.8 (3) °.…”

The structure of bis[dichloro-6-mercaptopuriniumcopper(I)] dihydrate: a refinement

“…While the gross structural features are, of course, similar to those reported by C & N, the purine ring geometry derived from our refinement differs markedly from that obtained previously. The bond lengths found for the coordinated purine ligand here are compared with those of C & N, and also with those reported for the free ligand and for other transition metal complexes of 6-mercaptopurine (Heitner & Lippard, 1974;Sletten & Apeland, 1975) in Table 2. It is apparent from an examination of Table 2 that the values which we have determined are consistent with those found in the C(4~(51 related systems.…”

“…We and others have recently been investigating the interactions of metal ions with purines and purine analogs (Purnell, Estes & Hodgson, 1976;Purnell, Shepherd & Hodgson, 1975;Heitner & Lippard, 1974;Sletten & Apeland, 1975; and references therein). We were, therefore, interested to see the report (Caira & Nassimbeni, 1975, hereinafter C & N) of the structure of a dimeric copper(I) complex of 6-mercaptopurine.…”

“…This interaction meets the criterion (Hamilton & Ibers, 1968) that both the O-H and the H...C1 separations are less than the appropriate sums of the van der Waals radii (Pauling, 1960;Bondi, 1964) and hence is probably a weak hydrogen bond. Caira & Nassimbeni (1975), (b) Heitner & Lippard (1974), (c) Sletten & Apeland (1975), (d) values given are the averages of two: Brown (1969); Sletten, Sletten & Jensen (1969).…”