ChemInform Abstract: SYNTHESIS OF TWO NEW PENDANT-ARM PENTAAZA-MACROCYCLIC LIGANDS, AND OBSERVATION OF PH-DEPENDENT REVERSIBLE EQUILIBRIUMS BETWEEN TRIGONAL-BIPYRAMIDAL AND SQUARE-PLANAR FORMS OF THEIR NICKEL(II) AND COPPER(II) COMPLEXES. CRYSTAL STRUCTUR

1984 ◽  
Vol 15 (52) ◽  
Author(s):  
N. W. ALCOCK ◽  
R. G. KINGSTON ◽  
P. MOORE ◽  
C. PIERPOINT
Keyword(s):  
Macrocyclic Ligands ◽  
Trigonal Bipyramidal ◽  
Pendant Arm ◽  
Square Planar ◽  
Ph Dependent

scholarly journals Crystallographic and structural characterization of heterometallic platinum compounds. Part II. Heterobinuclear Pt compounds with Pt⋯M (M = transition or lantanide metal) > 3.0 Å

2012 ◽  
Vol 10 (6) ◽  
pp. 1709-1759 ◽  
Author(s):  
Milan Melnik ◽  
Ondrej Sprusansky ◽  
Clive Holloway
Keyword(s):  
Transition Metal ◽  
Chlorine Atom ◽  
Structural Characterization ◽  
Platinum Compounds ◽  
Factors Affecting ◽  
Bond Lengths ◽  
Trigonal Bipyramidal ◽  
Square Planar ◽  
Independent Molecules

AbstractThis review covers almost two hundred and twenty heterobinuclear platinum compounds in which Pt⋯M separation is over 3.0 Å. The M is a transition metal (Cu, Ag, Au, Ti, V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni and Pd). There is an example of a lanthanide, Yb and a actinide, U. The Pt atom has oxidation numbers 0, +2 and +4. The Pt coordination geometries include trigonal planar Pt(0); square planar Pt(II); trigonal bipyramidal, and pseudo octahedral Pt(IV), with the most frequent being square planar. The most common ligands for Pt are P and C donor atoms, as well as a chlorine atom. The Pt — Ag distance of 3.002(1) Å is the shortest found in this series. There are examples which contain two crystallographically independent molecules, which differ mostly by degree of distortion and even one unique example, which contains eight such molecules. These are examples of distortion isomerism. Factors affecting bond lengths and angles are discussed and some ambiguities in coordination polyhedral are outlined.

Helicity interchange in the cadmium(II), mercury(II) and lead(II) complexes of two isomeric pendant arm tetraaza macrocyclic ligands

1995 ◽  
Vol 236 (1-2) ◽  
pp. 185-188 ◽  
Author(s):  
Ashley K.W. Stephens ◽  
Ramesh Dhillon ◽  
Stephen F. Lincoln ◽  
Kevin P. Wainwright
Keyword(s):  
Macrocyclic Ligands ◽  
Pendant Arm

Copper(II) and Nickel(II) Complexes of Pentaaza Macrocyclic Ligands

1987 ◽  
Vol 40 (2) ◽  
pp. 347 ◽  
Author(s):  
P Osvath ◽  
NF Curtis ◽  
DC Weatherburn
Keyword(s):  
Aqueous Solution ◽  
Solid State ◽  
Electronic Spectra ◽  
Macrocyclic Ligands ◽  
Distorted Octahedral Environment ◽  
Trigonal Bipyramidal ◽  
Octahedral Environment ◽  
Distorted Octahedral

The preparations of the pentaazamacrocyclic ligands 1,4,7,10,13-pentaazacyclopentadecane, cpad , l,4,7,l0,13-pentaazacyclohexadecane, ched , l,4,7,l0,14-pentaazacycloheptadecane, chad , 1,4,7,11,14-pentaazacycloheptadecane, cnad , 1,4,7,11,15-pentaazacyclooctadecane, cnad , 1,4,8,11,15-pentaazacyclooctadecane, cnad , 1,4,8,12,16-pentaazacyclononadecane, cnad , and 1,5,9,13,17-pentaazacycloeicosane, ceic , as well as the new linear pentaamine N-(3-aminopropy1)- N'-[3-[(3-aminopropyl)amino] propyl ]propane-1,3-diamine, tpah , are described. Copper(II) and nickel(II) complexes of the above ligands have been prepared and characterized. The nickel(II) complexes of the smaller macrocycles and the linear pentaamine contain NiII in a tetragonally distorted octahedral environment in the presence of coordinating anions or in aqueous solution but the [Ni( cnad )]2+ and [Ni( ceic )]2+ cations are five-coordinate both in the solid state and in aqueous solution. The copper(II) complexes of the macrocyclic pentaamines appear to be square-pyramidal on the basis of their electronic spectra, whereas the complex [cu( tpah )]2+ is probably trigonal- bipyramidal.

scholarly journals Square-Planar vs. Trigonal Bipyramidal Geometry in Pt(II) Complexes Containing Triazole-Based Glucose Ligands as Potential Anticancer Agents

2021 ◽  
Vol 22 (16) ◽  
pp. 8704
Author(s):  
Alfonso Annunziata ◽  
Davide Liberti ◽  
Emiliano Bedini ◽  
Maria Elena Cucciolito ◽  
Domenico Loreto ◽  
...  
Keyword(s):  
Small Molecules ◽  
Anticancer Agents ◽  
Biological Action ◽  
Cytotoxic Action ◽  
Trigonal Bipyramidal ◽  
Square Planar ◽  
Overall Stability ◽  
Square Planar Complexes ◽  
New Compounds ◽  
Tumorigenic Cell

This article describes the synthesis, characterization, and biological activity of novel square-planar cationic platinum(II) complexes containing glucoconjugated triazole ligands and a comparison with the results obtained from the corresponding five-coordinate complexes bearing the same triazole ligands. Stability in solution, reactivity with DNA and small molecules of the new compounds were evaluated by NMR, fluorescence, and UV–vis absorption spectroscopy, together with their cytotoxic action against pairs of immortalized and tumorigenic cell lines. The results show that the square-planar species exhibit greater stability than the corresponding five-coordinate ones. Furthermore, although the square-planar complexes are less cytotoxic than the latter ones, they exhibit a certain selectivity. These results simultaneously demonstrate that overall stability is a fundamental prerequisite for preserving the performance of the agents and that coordinative saturation constitutes a point in favor of their biological action.

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