Synthesis, molecular, crystal and electronic structure of ½RuCl 2 ðPPh 3 Þ 2 ðC 3 N 2 H 4 Þ 2  J.G. Malecki a, * , J.O. Dzie ßgielewski a , R. Kruszynski b , T.J. Bartczak b a Department of Inorganic and Radiation Chemistry, Institute of Chemistry, University of Silesia, 9th Szkolna St., 40-006 Katowice, Poland b X-Ray Crystallography and Crystal Chemistry Group, Institute of General and Ecological Chemistry, Technical University of L od z, 116 _ Zeromski St., 90-924 L od z, Poland Received 20 November 2002; accepted 29 January 2003 Abstract The reaction of ½RuCl 2 ðPPh 3 Þ 3  complex with pyrazole has been examined. A new ruthenium complex – ½RuCl 2 ðPPh 3 Þ 2 ðC 3 N 2 H 4 Þ 2  has been obtained and characterised by IR and UV–Vis measurements. Crystal and molecular structure of the complex has been determined. Ó 2003 Elsevier Science B.V. All rights reserved. Keywords: Ruthenium; Pyrazole; X-ray structure; Tertiary phosphine complexes 1. Introduction Pyrazole and imidazole derived ligands are widely used in syntheses of transition metals coordination compounds. These ligands can act as terminal or bridging, and their coordination chemistry is extensively explored. The results of the up-to-now researches are presented in review papers [1–4]. The majority of works deal with complexes of copper, iron, nickel and plati- num. Less attention is paid to the derivatives of ruthe- nium. The ruthenium imidazole and N-methylimidazole complexes with tertiary phosphines such as ½RuCl 3 ðPPh 3 ÞL 2 , ½RuCl 2 ðPPh 3 Þ 2 L 2  (where L ¼ imid- azole or methylimidazole) have been known since 1988 [5]. Earlier Stephenson and co-workers reported a range of Ru(III) an Ru(II) triphenylophosphine complexes containing other N-donors such as pyridine, bipyridyl, 1,10-phenantroline [6]. Ruthenium triphenylphosphine complexes with aminoacids and peptides have been prepared and examined recently [7,8]. In this paper, we present the synthesis, spectroscopic properties and the crystal structure of a new pyrazole ruthenium(II) complex. 2. Experimental Triphenylphosphine and RuCl 3  3H 2 O were pur- chased from Aldrich Chemical, pyrazole and acetone were purchased from P.O.Ch. Gliwice and used without further purification. The ½RuCl 2 ðPPh 3 Þ 3  complex was synthesised according to the literature method [9]. The solvent used to the reaction was argon saturated. 2.1. Synthesis of ½RuCl 2 ðPPh 3 Þ 2 ðC 3 N 2 H 4 Þ 2  2ðCH 3 Þ 2 CO The ½RuCl 2 ðPPh 3 Þ 3  (0.2 g) was added to 50 cm 3 of pyrazole (0.2 g) solution in acetone and the mixture was stirred for 30 min. The red crystals suitable for X-ray crystal analysis grew from standing overnight reaction mixture. Yield 78%. IR (KBr): 3268 m NH ; 3058; 3126 m CH ; 1712 m C@O ; 1516 m CN , m C@C ; 1482 d ðC–CH in the planeÞ ; 1433 m P–Ph ; 1044 d ðC–CH in the planeÞ ; 765 d ðC–C out of the planeÞ ; 749 d ðC–C out of the planeÞ ; 696 d ðC–C in the planeÞ ; 604 m P–Ph . Anal. Calc. for C 48 H 50 Cl 2 N 4 O 2 P 2 Ru: C 60.76%; H 5.31%; N 5.90%. Found: C 60.74; H 5.29; N 5.88%. 1 H NMR (d; CD 2 Cl 2 ): 11.73 (s 2H, NH); Inorganic Chemistry Communications 6 (2003) 721–724 www.elsevier.com/locate/inoche * Corresponding author. E-mail addresses: gmalecki@us.edu.pl (J.G. Malecki), kruszyna@ ck-sg.p.lodz.pl (R. Kruszynski). 1387-7003/03/$ - see front matter Ó 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S1387-7003(03)00066-2