PREPARATION AND STRUCTURE OF CIS-[(ETHYLENEDIAMINE)BIS(1,3,9-TRIMETHYLXANTHINE)PLATINUM(II)] NITRATE DIHYDRATE AND CIS-[(ETHYLENEDIAMINE)BIS(1,3,9-TRIMETHYLXANTHINE)PLATINUM(II)] HEXAFLUOROPHOSPHATE - EFFECT OF INTRAMOLECULAR AND INTERMOLECULAR INTERACTIONS ON MOLECULAR-CONFORMATION IN THE SOLID-STATEAM

• Type: Article in International Scientific Journal
• Date: 1982

Authors

ORBELL, JD (Author) Other; WILKOWSKI, K (Author) Other; DECASTRO, B (Author) FCUP; MARZILLI, LG (Author) Other; KISTENMACHER, TJ (Author) Other

Journal

Title: Inorganic Chemistry

Vol. 21

Pages: 813-821

ISSN: 0020-1669

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 24 Citations

Scopus - 16 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-005-6GK

DOI: 10.1021/ic00132a067

Abstract (EN): The synthesis, solution 1H NMR spectrum, and solid-state molecular and crystal structure of cis-[(en)Pt(1,3,9-TMX)2](NO3)2·2H 2O and cis-[(en)Pt(1,3,9-TMX)2](PF6)2 (where 1,3,9-TMX = 1,3,9-trimethylxanthine) are reported. The NO3 - salt crystallizes in the monoclinic system, space group P21/c, with a = 22.215 (24) Å, b = 7.945 (6) Å, c = 16.463 (6) Å, ß = 111.91 (4)°, V = 2695.8 Å3, Z = 4 (based on a molecular weight of 803.62 for [Pt(C2H8N2)(C8H10N 4O2)2](NO3) 2·2H2O), Dmeasd = 1.98 (1) g cm-3, and Dcalcd = 1.98 g cm-3. The PF6 - salt also crystallizes in the monoclinic system, space group C2/c, with a = 14.880 (3) Å, b = 9.236 (2) Å, c = 21.810 (4) Å, ß = 91.17 (1)°, V = 2996.8 Å3, Z = 4 (based on a molecular weight of 933.50 for [Pt(C2H8N2)(C8H10N 4O2)2](PF6)2), Dmeasd = 2.07 (1) g cm-3, and Dcalcd = 2.07 g cm-3. Intensity data for 7320 (NO3 - salt) and 4289 (PF6 - salt) symmetry-independent reflections were collected by utilizing the ¿-2¿ scan mode on an automated diffractometer employing graphite-monochromatized Mo K¿ radiation. Both structures were solved by standard heavy-atom Patterson and Fourier techniques and have been refined by full-matrix least-squares analysis (R = 0.048 and 0.044 for the NO3 - and PF6 - salts, respectively). The primary coordination sphere about the Pt(II) center is approximately square planar in each complex cation, with the N atoms of the en chelate and the N(7) atoms of the cis-bound 1,3,9-TMX ligands occupying the four coordination sites. Whereas in the NO3 - salt the complex cation has only approximate 2(C2) symmetry, such symmetry is crystallographically required for the cation in the PF6 - salt. Principal intracomplex geometrical parameters for the NO3 - salt are as follows: Pt-N(en) = 2.012 (4), 2.026 (3) Å; Pt-N(7) = 2.010 (3), 2.021 (4) Å; N(7)-Pt-N(7) = 89.1 (1)°; interbase dihedral angle = 70.6°; base/PtN4 coordination plane dihedral angles = 116.8, 119.5°. These same parameters for the PF6 - salt are as follows: Pt-N(en) = 2.029 (5) Å; Pt-N(7) = 2.018 (4) Å; N(7)-Pt-N(7) = 91.6 (2)°; interbase dihedral angle = 87.3°; base/PtN4 dihedral angle = 121.4°. A detailed comparison is made among the conformational aspects of the present complexes and those displayed by a variety of other cis-bis(N(7)-bound 6-oxopurine)platinum(II) systems. © 1982 American Chemical Society.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9