Thermal, spectroscopic, and structural properties of aqua(malonato-O,O′)(1,10-phenanthroline)copper(II) hydrate (1/1.5)

Abstract

Aqua(malonat0-0,O') (1,l O-phenanthroline)copper(ii) crystallizes in the triclinic space group P i with a = 11.560(4), b = 11.734(5), c = 12.491 (2) A, a = 92.1 2(2), p = 105.50(2), y = 109.28(3)", and Z = 2. The structure consists of two independent monomeric [Cu(phen)(mal) ( H 2 0 ) ] molecules with three water molecules in the lattice. The CuN,O,O' chromophore is distorted square pyramidal with a symmetrically co-ordinated phen molecule (mean CU-N 2.01 8 A) and a symmetrically coordinated malonate ion (mean Cu-0 1.91 4 A) in the plane of the square pyramid and a water molecule at 2.266 A. The relatively short Cu-0 distance has been attributed to phen being a stronger n-acid. The compound and its several related complexes show complete loss of water molecules at ca. 100 "C followed b y stepwise degradation of the organic ligands. Thermogravimetric analysis and visible reflectance spectral results are discussed in relation to the k n o w n structure of the title compound.Ternary complexes of the copper(1r) ion containing an a,a'-diimine and an oxygen-donor ligand have been extensively investigated.' Recently it has been reported that the complex containing the 2,2'-bipyridyl (bipy) and the oxalate ion (ox) exists in two forms [Cu(bipy)(ox)(H20)]*2H20 (A) and [Cu(bipy)(ox)]-2H20 (B). X-Ray structural analyses demonstrate that the former consists of a monomeric copper(i1) ternary complex while the latter contains a bridging oxalate ion. In view of the close structural similarities between 1,lO-phenanthroline (phen) and bipy as well as between malonate and oxalate, the ternary complex [Cu(phen)(mal)(H,O)] has now been reexamined through thermogravimetric analysis (t.g.a.1, spectroscopic and structural measurements. As there have been few studies on the thermoanalytical behaviour of these complexes the t.g.a. has been carried out on several related complexes in the present investigation. Such results are useful in understanding the properties and structural characteristics of the complexes in the solid state. ExperimentalPreparation of' Complexes.-The complexes were prepared according to the methods described earlier.'** Crystals of [Cu(phen)(mal)(H20)].1.5H20 were obtained by slow evaporation of a water-methanol (3:2) solution. A blue crystal of approximate dimensions 0.12 x 0.42 x 0.47 mm was sealed in a 0.5-mm glass capillary tube for X-ray data collection.fliysicul Mc.usurements.-The reflectance spectra of the solid complexes were recorded using a Shimadzu UV 240 spectrophotometer and a Perkin-Elmer Lambda 9 u.v.-visible-near i.r. spectrophotometer equipped with a standard reflectance attachment. The i.r. spectra (4 000-200 cm-') obtained from KBr or CsI pellets were recorded with a Perkin-Elmer 599 i Supplementary data acailahle (No. SUP 56604, 5 pp.

Aqua(5,6-dimethyl-1,10-phenanthroline-N,N')(malonato-O,O')copper(II) hydrate

“…The angle between the planes of the coordination-plane atoms and the phenanthroline molecule is 6.08 (6) ° , and that formed with the malonate moiety, is 1.85(8) °. Average Cul--N distances [2.O2(1)A] are longer than Cul---O distances [1.92(1)A], as observed in many complexes with amines and malonate (Kwik et al, 1986;Borghi, 1987;Pajunen & Nasakkala, 1977;Hamalainen & Pajunen, 1973;Kansikas & Hamalainen, 1977;Suresh & Bhadbhade, 1997;Kawata et al, 1995).…”

Metal Derivatives of Thiosemicarbazones: Crystal and Mole­cular Structures of Mono‐ and Dinuclear Copper(II) Complexes with N1‐Subsitituted Salicylaldehyde Thiosemicarbazones

“…There has been considerable interest in the compounds containing N,N donor co-ligands such as bipyridine and phenanthroline because of their versatile self-assembling properties and tendency to act as building blocks in the design of metalligand networks. [20,21] However, transition metal polypyridyl throline, tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline). In dinuclear complex 2, one ligand is O,N 3 ,S-chelating, while second is O,N 3 ,S-chelation-cum-N 2 -bridging; and in all others thio-ligands are O,N 3 ,S-chelating.…”

Co-operation of π⋯π, Cu(II)⋯π, carbonyl⋯π and hydrogen-bonding forces leading to the formation of water cluster mimics observed in the reassessed crystal structure of [Cu(mal)(phen)(H2O)]2·3H2O (H2mal=malonic acid, phen=1,10-phenanthroline)

“…doi:10.1016/j.molstruc.2009.12.048 weak forces operating simultaneously. In the present paper we report the re-determined [62] single-crystal X-ray structure of [Cu(mal)(phen)(H 2 O)] 2 Á3H 2 O (1) [mal = malonate dianion; phen = 1,10-phenanthroline] complex with improved R value (0.0263 as compared to 0.047 in [62]) and importantly with the water hydrogen atom positions determined from the difference Fourier map. This has helped us to unravel an important way in which the water molecules do cooperate among themselves and interact with the malonate ligands stabilizing the crystal packing crucially.…”

“…for C 30 89. This method of preparation is essentially the same as originally described [62] excepting that we used a different Cu(II) salt instead of CuCl 2 .2H 2 O used by Kwik et al [62] and the order of addition of the reagents differ.…”

“…A hydrogen bond is indeed observed for O8 which interacts with the oxygen atom O5 of a neighboring Cu(1) unit (O5-H5BÁ Á ÁO8 = 2.7075(16) Å; Table 3). Moreover, the distance D (corresponding to the distance between the carbonyl oxygen atom and the ring centroid) and the angular distribution significant carbonyl (p) -p (aromatic) stacking interaction exists and due to its recent recognition, was naturally overlooked in the previous and first report of 1 [62]. However, we have unraveled an interesting scenario in which the strong hydrogen bonding force [O5-H5BÁ Á ÁO8 and O10-H10BÁ Á ÁO4] and weak carbonyl-p force can act in unison cooperating with each other although they operate in nearly orthogonal direction.…”