Square-planar complexes bis

The red square planar complex bis(dimethylglyoximato)-nickel(II), [Ni(Hdmg)2] (Figure 21.28a), is used for gravimetric analysis of nickel Ni(II) is precipitated along with Pd(II) when the ligand H2dmg in weakly ammoniacal... 

The mixed-donor tridentate ligands bis[2-diphenylphosphino)ethyl] benzylamine (dpba) and bis[2-(diphenylarsino)ethyl] benzylamine (daba) form square-planar complexes with IrCl and IrPPh3 moieties.664... 

Scheme 2 Different redox states of square-planar nickel bis(edt) complexes...

Fig. 12.28 Conformational interactions in bis(chelate) square planar complexes (a) AA form (b) A8 form. AH hydrogen atoms except four have been omitted for greater clarity. Dashed lines represent inter-nng H-H repulsions. [Modified from Corey, E. J. Bailar. J. C.. Jr. 

Use (he data lo calctfate A, and k2 for substitution bi this square planar complex. 

Porphyrin (8) and phthalocyanine complexes stabilize a square planar structure, probably as a result of extensive electron delocalization. Square planar complexes often give paramagnetic bis adducts with a Irans octahedral geometry. 

Bis(pyrrole-2-aldiminato)nickel(II) complexes (125) are diamagnetic in the solid state when R = H, Pr, Pr and Et, and paramagnetic pseudotetrahedral when R = Bu. 1001-1003 In solution there exists an equilibrium between square planar and tetrahedral species when R = Pr1, Bus and Bu Such equilibria were also investigated for complexes of the type (126) obtained from the condensation reaction in basic media of o-aminobenzaldehyde and a number of diamines in the presence of nickel(II).1004-1007 Square planar complexes (127)1008,1009 and (128)1010 were obtained with deprotonated pyridinecarboxamide ligands. In these complexes the Ni—N (amide) bond distance (184-187 pm) is shorter than the Ni—N (pyridine) distance (192-195 pm). 

Distorted Square Planar Four-Coordinate The first example of helical chirality for a square planar complex with achiral ligands is cis-bis(2,6-diphenyl-... 

P-. As-, and Sb-donor ligands. H N.m.r. measurements at 60, 100, and 220 MHz have been made for the complexes [PdCl2 Ph3 nP(CH2Ph)n 2] (n = 1, 2, or 3).82 The different spectra observed at these three frequencies have been explained in terms of hindered rotation about the P—C bonds when n = 2 and 3 and probably also for n = 1. The square-planar complexes [PdX2L] [L = cis-1,2-difluoro-1,2-bis(diphenylphosphino)ethylene X = Cl, Br, I, or SCN] have been obtained by treatment of [PdX4]2- with L.83 The complexes were characterized by chemical analysis and their visible spectra recorded. In addition, difluorophosphonato-complexes [M(PF20)4]2 (M = Pd or Pt) have been isolated as their JV-allyl-pyridinium salts (equation 16) and their n.m.r. and i.r. spectra reported.84... 

Square-planar complexes of the unusual ligand 2,ll-bis(diphenylphosphinoethyl)-benzo[c]phenanthrene) (44), which is capable of spanning trans positions, have been obtained by reaction with suitable compounds of Pt, Pd, and Ni.91 The complexes are monomeric and non-electrolytes in CH2C12 and the trans-configuration of P atoms was established by H n.m.r. Other similar complexes containing a diphosphine... 

There are a small number of homoleptic Fe and Co bis(dithiolene) examples that are found as monomeric structures. The average Co S bond lengths of five square-planar complexes range from 2.162 to 2.198 A. The average Co S bond length of the single distorted-tetrahedral example is longer at 2.297 A. Three... 

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