The Infrared Spectra of Some Titanium (Iv) Complexes With Primary Diamines

Abstract

A series of titanium(1V) halide -diamine complexes have been prepared and their infrared spectra measured in the solid state between 4 000 and 300 cnl-'. The configuration of the ligand and extent of aminolysis of the titanium-halide bond are discussed in relation to the spectra. Some assignments are proposed in the 600-300 cm-I region for the ethylenediamine complexes. INTRODUCTION An extensive study of the reaction between titaniuin(1V) halides and primary monoamines has shown that the primary arnines solvolyze the metal-halogen bond (1). By comparison, little is known of the reaction with primary diamines. Fowles and i\'IcGregor (2) reported an ethylenediainine (en) complex, TiCl2[HN(CH2)2NHz]z(en)z, and suggested that the ligands were chelated t o the metal. More recently Sumarokova and Sakenova (3, 4) claimed no aminolysis of the Ti-Cl bond occurred in the complexes TiC14.2en, TiC14. 3en, and TiC14.4en. However, there was evidence for aminolysis in the reaction with hexamethylenediarnine (HMD), and the compounds TiCl3[HN(CH2)6NH?1 .nHI\IID, where n = 1, 2, and 3, were reported (4). No spectroscopic examination of these compounds has been offered t o date. I n this paper we describe the preparation of a number of titanium(1V) halide -diarnine complexes including a series of 1 : 1 adducts. T h e infrared data for these compounds in the range 4 000 t o 300 cm-I is given in Table I. E X P E R I M E N T A L Materials and Manipz~lationSpecial precautions were taken to exclude water from the apparatus and chemicals, and all reactions were conducted in an atmosphere of dry nitrogen. The amines and solvents were dried by refluxing over sodium and then fractionally distilled. The titanium halides were distilled or sublimed into the reaction vessels immediately before use.The complexes were all prepared by the same general method. Solutions of the reactants in benzene were mixed in known molar ratios. Reaction was generally immediate and heat was evolved. The resulting mixture was stirred and occasionally heated for a period of time. The products, which were all insoluble, were filtered, washed with hot benzene, and dried in vacuo. All the products reacted vigorously with water and were hydrolyzed rapidly in air. The complexes were nonvolatile and insoluble in any solvent with which they did not react.The infrared spectra were all determined as mulls in Nujol and l~exachlorobutadiene-1,3 between NaCl or KRS-5 plates on a Beckman I.R. 10 grating instrument.Analyses were obtained as previously described ( 5 ) and the data is presented in Table 11. RESULTS A N D DISCUSSIONA number of questions remain to be answered with regard to the titaniurn(1V) halidediamine complexes so far reported in the literature: (a) the extent t o which arninolysis of the Ti-X bond (X = C1, Br, or I) occurs; (b) whether the diamine is acting as a chelate or as a trans bridging unit between two different metal atoms thus forming polymeric chains; and (c) a t what value of n in the chain HzN(CH2),NH2 would there be a possible change f...

MOCVD of TiO2 Thin Films using a Heteroleptic Titanium Complex: Precursor Evaluation and Investigation of Optical, Photoelectrochemical and Electrical Properties

“…The bands around 600–540 cm −1 were unambiguously assigned to the TiO bond, and were not observed in the ligand spectrum. TiN stretching frequencies, which typically appear below 400 cm −1 , could not be observed . The region between 1200 and 1000 cm −1 was enriched with multiple peaks expected for the CO and CN stretching present in the molecule.…”

Normal coordinate analysis of titanium(IV) halide: monoethylenediamine complexes

“…The assignments also agree with those previously reported (1) except for those at 442 and 315 cru-' in the chloride complex and at 435 cm-I in the bromide complex. For the chloride complex the calculated frequencies of 364 and 295 cni-I were very sensitive to changes of the Ti-Cl stretching force constant, as also was the calculated frequency of 497 cm-I.…”

“…We have been able to compare only 9 of these values with observed values because of limited experimental data. The comparisoil of those frcquencies indicates that the proposed chelate structure for tlie Ti(en)X, complexes is probable, and also supports the original assignments for the Ti-N stretching frequencies (1).…”

“…A comparable argurnent leads to a reassignment of the observed band at 435 cm-I in the bromide complex to the out of plane Ti-Br stretching frequency. Can A C-C stretching frequency was not assigned by Horley and Torrible (1). However, the bands they reported at 981 and 978 cm-I for the chloride and bromide complex respectively, correspond closely to the band at 980 cni-' assigned to the C-C stretching frequency by Sabatini and Califaiio (8) for free ethylenediamine.…”

“…The preparation and infrared spectra of the compounds Ti(en)C1, and Ti(en)Br, have bee11 reported recently (1). The spectra were found to be qualitatively consistent with a chelate structure with the ethylenediamine in the ga~tche configuration.…”