Preparation and Characterization of a Diamagnetic and Dinuclear Titanium(III) Formamidinate Complex. Evidence for the Existence of a Ti−Ti Bond?

Abstract

The new diamagnetic Ti(III) complex (CyNC(H)NCy)(4)Ti(2)Cl(2).2THF (1) containing a short Ti-Ti distance was prepared and crystallographically characterized. Ab initio unrestricted Hartree-Fock calculations suggested the presence of a Ti-Ti bonding interaction. Crystal data for 1 are as follows: C(60)H(108)N(8)Ti(2)Cl(2)O(2), FW 1140.27, monoclinic Pn, a = 10.4688(9) Å, b = 14.4579(9) Å, c = 21.421(1) Å, beta = 100.227(9) degrees, V = 3190.6(7) Å(3), Z = 2, D(calc) = 1.187 g/cm(3), F(000) = 1236, &mgr; = 3.75 cm(-)(1), T = -158 degrees C, R = 0.074, R(w) = 0.075, GOF = 3.64 for 540 parameters and 4630 reflections out of 5771 unique reflections observed.

Bicyclic-guanidines, -guanidinates and -guanidinium salts: wide ranging applications from a simple family of molecules

“…Most recently, group 4 metal paddlewheel compounds containing [hpp] À have been targeted, encouraged by reports of amidinate derivatives containing a Ti-Ti bonded core. 140 Reduction of Ti(hpp) 2 Cl 2 118 with potassium graphite afforded a compound that analyzed as Ti 2 (hpp) 4 Cl 2 . 141 However, X-ray analysis indicated that only two [hpp] À anions were bridging and that, rather than the expected k 1 N,k 2 N 0 -mode (B, Fig.…”

Topological analysis of the metal-metal bond: A tutorial review

“…Representative complexes of single Ti-Ti and Zn-Zn bondsThe short intermetallic distance (2.543 Å ) and the diamagnetism of alkoxo-bridged dinuclear complexes of Ti(III) indicated the presence of a Ti-Ti bond, as revealed by an attractor of weak ELF value located between the Ti(III) centres[297]. A short intermetallic contact (2.942 Å ) in a dinuclear Ti(III) formamidinate complex was also assigned to the presence of a single Ti-Ti bond on the basis of the analysis of the calculated electron density (bond order 0.96)[298]. Carmona's discovery of the first structurally characterized example of a stable Zn-Zn bond in decamethyldizincocene (Cp * Zn−ZnCp * ), with a intermetallic distance of 2.305 Å and two parallel Cp * rings[23] prompted a number of theoretical investigations[23].…”

Di- and TrimanganeseN,N′-Dicyclohexylformamidinate Complexes

“…This idea is supported by the fact that substantial amounts of n-butane were consistently detected in the reaction mixtures of reproducible reactions. It should be also mentioned that the N,N'-dicyclohexylformamidinate lithium salt used in this work was repeatedly prepared following the procedure normally used for the preparation of Ti, [22] V, [2b] and Cr [3c] derivatives of the same ligand.…”