η⁵ and η⁶ - cyclic π-perimeter hydrocarbon platinum group metal

complexes of 3-(2-pyridyl)pyrazole derived ligands with a pendant

nitrile group: Syntheses, spectral and structural studies

GLORIA SAIREM^a, VENKATESWARA RAO ANNA^a, PENG WANG^b, BABULAL DAS^c and

MOHAN RAO KOLLIPARA^a,*

^aDepartment of Chemistry, North Eastern Hill University, Shillong 793 022, India

^bDepartment of Chemistry, McMaster University, 1280 Main StreetWest, Hamilton, Ontario L8S 4M1, Canada

^cDepartment of Chemistry, Indian Institute of Technology, Guwahati 781 039, India

e-mail: mohanrao59@gmail.com

Abstract. Reaction of two equivalents 4-{(3-(pyridine-2-yl) 1H-pyrazole-1-yl}methyl benzonitrile (L1) and

3-{(3-(pyridine-2-yl)1H-pyrazole-1-yl}methyl benzonitrile (L2) with one equivalent of [(η⁶-arene)Ru(μ-

Cl)Cl]₂ and [Cp*M(μ-Cl)Cl]₂ in methanol yielded mononuclear complexes of the formulae [(η⁶-

arene)Ru(L1/L2)Cl]BF₄{arene =C₆H₆ (1, 6); C₁₀H₁₄ (2, 7); C₆Me₆ (3, 8)} and [Cp*M(L1/L2)Cl]PF₆/BF₄

{Cp*= η⁵-C₅Me₅, M=Rh (4, 8); Ir (5, 10)}. These complexes are characterized by IR, 1H NMR and identities

of the structure are established by single crystal XRD studies of some of the representative complexes. It is

confirmed from the spectral studies that the nitrile group is not taking part in complexation; instead it remains

as a free pendant group only.

Graphical Abstract

Keywords. Arene; pentamethylcyclopentadienyl; ruthenium; rhodium; 3-(2-pyridyl)pyrazole.