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Coordination Plane (coordination + plane)

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Chemistry	100%

Selected Abstracts

NMR Study of L-Shaped (Quinoxaline)platinum(II) Complexes , Crystal Structure of [Pt(DMeDPQ)(bipy)](PF6)2

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2004
Enrico Rotondo
Abstract A 1H and 13C NMR study of nine PtII complexes of DMeDPQ [6,7-dimethyl-2,3-bis(2-pyridyl)quinoxaline] and BDPQ [2,3-bis(2-pyridyl)benzo[g]quinoxaline], and the crystal structure of one of them, are reported. The results are consistent with Cs symmetry of "L-shaped square-planar complexes". The rigid seven-membered chelated quinoxaline ligand holds the fused aromatic rings nearly perpendicular to the PtII coordination plane, generating the peculiar L-shaped structure. Ancillary ligands in the residual coordination sites are: a) bidentate flexible-planar 2,2,-bipyridine (bipy; complexes 1 and 2); b) bidentate rigid-planar dipyrido[3,2- a:2,3,- c]phenazine (dppz) or benzo[b]dipyrido[3,2- h:2,,3,- j]phenazine (bdppz; complexes 3,6); or c) 3-substituted monodentate pyridines (3-Rpy; complexes 7,9). The L-shaped geometry has been exploited to gain insight into the steric and dynamic features that regulate the noncovalent interactions of these square-planar complexes with DNA. We have shown previously, for [Pt(bipy)(n -Rpy)2]2+, that bipy twisting can be frozen out on the NMR timescale below 260 K. Preservation of the Cs symmetry at low temperature indicates a lack of bipy fluxionality within these L-shaped structures. The static butterfly-like symmetric orientation of the quinoxaline pyridyl rings accounts for the hampered twisting of Pt(bipy), which is otherwise assisted by the synchronous "windscreen wiper" conrotatory rocking of the ancillary pyridine rings. The L-geometry can also be used to monitor the ancillary n -Rpy rotation by NMR spectroscopy. The quasi-vertical quinoxaline pyridyl rings alignment leave room in the coordination plane for the crossing of the opposite pyridine rings, thereby reducing their rotational barriers about the Pt,N bond. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

trans -Bis[1-benzyl-3-(2,3,4,5,6-pentafluorobenzyl)benzimidazol-2-ylidene]dibromopalladium(II)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2006
Aytaç Gürhan Gökçe
The title compound, [PdBr2(C21H13F5N2)2], crystallizes with two independent centrosymmetric conformational isomers having a square-planar coordination at the Pd atom. The conformational isomers differ by the ligands having a cis or trans orientation of their benzyl and pentafluorobenzyl rings with respect to the benzimidazole ring plane. The benzimidazole rings are rotated with respect to the coordination plane of the metal by 79.1,(2) and 75.2,(1)° for molecules A and B, respectively. The Pd,Br bond lengths are 2.4218,(8) and 2.4407,(10),Å for molecules A and B, respectively, and the Pd,C bond lengths are 2.030,(8) and 2.018,(9),Å. The crystal structure contains two types of C,H,F and one type of C,H,Br intramolecular contact, as well as C,H,, interactions. [source]

Platinum Complexes of Naphthalene-1,8-dichalcogen and Related Polyaromatic Hydrocarbon Ligands

CHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2004
Stephen M. Aucott Dr.
Abstract Platinum bisphosphine complexes bearing dichalcogen-derivatised naphthalene, acenaphthene or phenanthrene ligands have been prepared by either oxidative addition to zero-valent platinum species or from [PtCl2(PPhR2)] (R=Ph or Me) and the disodium or dilithium salts of the parent disulfur, diselenide or mixed S/Se species. The parent naphthalene, acenaphthene and phenanthrene chalcogen compounds were treated with either [Pt(PPh3)4] or [Pt(C2H4)(PMe3)2] (prepared in situ from [PtCl2(PMe3)2], ethene and sodium naphthalide or super hydride [LiBEt3H]) to give the appropriate platinum(II) species. The dilithium salts of 1,8-E2 -naphthalene (E=S or Se) prepared in situ by reduction of the EE bond with [LiBEt3H] were treated with [PtCl2(PPh3)2] to give [Pt(1,8-E2 -nap)(PPh3)2]. The tetraoxides [Pt(1,8-(S(O)2)2 -nap)(PR3)2] (PR3=PPh3 or PMe2Ph) were prepared in a similar metathetical manner from the appropriate [PtCl2(PR3)] complexes and the disodium salt of naphthalene 1,8-disulfinic acid (1,8-(S(O)ONa)2 -nap). The X-ray structures of selected examples reveal bidentate coordination with the naphthalene-E2 unit hinged (111,137°) with respect to the coordination plane. The naphthalene ring suffers significant distortion from planarity. [source]

[N,N,-Bis(salicylidene)-2,2-dimethyl-1,3-propanediaminato]nickel(II) and [N,N,-bis(salicylidene)-2,2-dimethyl-1,3-propanediaminato]copper(II)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2001
Cengiz Arici
In the title compounds, {2,2,-[2,2-dimethyl-1,3-propanediylbis(nitrilomethylidyne)]diphenolato-,4N,N,,O,O,}nickel(II), [Ni(C19H20N2O2)], and {2,2,-[2,2-dimethyl-1,3-propanediylbis(nitrilomethylidyne)]diphenolato-,4N,N,,O,O,}copper(II), [Cu(C19H20N2O2)], the NiII and CuII atoms are coordinated by two iminic N and two phenolic O atoms of the N,N,-bis(salicylidene)-2,2-dimethyl-1,3-propanediaminate (SALPD2,, C17H16N2O22,) ligand. The geometry of the coordination sphere is planar in the case of the NiII complex and distorted towards tetrahedral for the CuII complex. Both complexes have a cis configuration imposed by the chelate ligand. The dihedral angles between the N/Ni/O and N/Cu/O coordination planes are 17.20,(6) and 35.13,(7)°, respectively. [source]