Nickel(II) chloride adducts of 4 0 -phenyl-2,2 0 :6 0 ,2 00 -terpyridine Edwin C. Constable a, * , David Phillips b , Paul R. Raithby b a School of Chemical Sciences, University of Birmingham, Edgbaston, Birmingham, UK B15 2TT b University Chemical Laboratory, Lensfield Road, Cambridge, UK CB2 1EW Received 7 March 2002; accepted 14 April 2002 Abstract The reaction of 4 0 -phenyl-2,2 0 :6 0 ; 2 00 -terpyridine I with nickel(II) chloride gives a 1:1 adduct which we have structurally char- acterised and shown to be comprised of two species of stoichiometry fNiðIÞCl 2 g; the first is a five-coordinate [Ni(I)Cl 2 ] complex and the other is a dinuclear species containing two six-coordinate nickel centres [(I)ClNiðl-ClÞ 2 NiðIÞCl]. Ó 2002 Elsevier Science B.V. All rights reserved. Keywords: 2,2 0 :6 0 ; 2 00 -Terpyridine; Nickel complex; Crystal structure; Supramolecular chemistry 1. Introduction 2,2 0 :6 0 ; 2 00 -Terpyridine (tpy) is one of the prototype oligopyridine metal-binding motifs that play a pivotal role in metallosupramolecular chemistry [1–3]. How- ever, although much of the current attention is centred upon highly functionalised derivatives [4], the parent ligand itself and simple derivatives may still yield a few surprises. In this paper, we describe some studies that we made of the interaction of nickel(II) chloride with 4 0 - phenyl-2,2 0 :6 0 ; 2 00 -terpyridine I which was used as a model for the more highly functionalised ligand 4 0 -(4- pyridyl)-2,2 0 :6 0 ; 2 00 -terpyridine II that we have utilised in the assembly of supramolecular arrays [5]. The reaction of MX 2 , where X is a potentially coor- dinating anion, with tpy in a coordinating solvent S can result in a number of species, the most commonly ob- served of which are [M(tpy)X 2 ], [M(tpy)X 2 S], [M(tpy)S 2 X]X, and [MðtpyÞ 2 ][MX 4 ]. In the case of nickel(II) halide adducts of tpy, the lability of the d 8 metal centre leads to additional complications, although a number of general features emerge [3]. The thermal decomposition of ½NiðtpyÞ 2 X 2 (X ¼ halide) leads to five- coordinate complexes [Ni(tpy)X 2 ] [6–8], which may also be obtained directly from NiX 2 and tpy under a variety of conditions [7–9]. In contrast, the {Ni(tpy)X 2 } species obtained from the reaction of tpy with ½NiX 4  2 is cor- rectly formulated as ½NiðtpyÞ 2 ½NiX 4  [10]. Under other conditions, hydrated six-coordinate species such as [Ni(tpy)ClðH 2 OÞ 2 ]Cl  nH 2 O have been isolated and structurally characterised [9,11]. Although no single crystal structural determination of [Ni(tpy)Cl 2 ] has been reported, the structural assignment is based upon a comparison of powder X-ray data [8] to those of [Zn(tpy)Cl 2 ] [12–14]. We now report the structural characterisation of two complexes of empirical formu- lation {Ni(I)Cl 2 }. 2. Experimental 2.1. Synthesis of fNiðIÞCl 2  0:5H 2 Og Asolutionof I (0.400g,1.29mmol)inacetone(40 cm 3 ) was added to a solution of ½NiðH 2 OÞ 6 Cl 2 (0.449 g, 1.89 mmol) in ethanol (25 cm 3 ) to give a brown solution from Inorganic Chemistry Communications 5 (2002) 519–521 www.elsevier.com/locate/inoche * Corresponding author. Tel.: +44-121-4141-4361; fax: +44-121-414- 4403. E-mail address: e.c.constable@bham.ac.uk (E.C. Constable). 1387-7003/02/$ - see front matter Ó 2002 Elsevier Science B.V. All rights reserved. PII:S1387-7003(02)00461-6