Hexanuclear Copper(II) Cages Built on a Central {μ 3 -O···H···μ 3 -O} Moiety, 1,3-Bis(dimethylamino)-2-propanolato and Capping R- phosphonates: Crystal Structures, Magnetic Behavior, and DFT Studies Saskia Speed, † Ramon Vicente, † Daniel Aravena, †,‡ Eliseo Ruiz, †,‡ Olivier Roubeau, § Simon J. Teat, ∇ and M. Salah El Fallah* ,† † Departament de Química Inorga ̀ nica, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain ‡ Institut de Química Teò rica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain § Instituto de Ciencia de Materiales de Aragó n (ICMA), CSIC and Universidad de Zaragoza, Plaza San Francisco s/n, 50009 Zaragoza, Spain ∇ Advanced Light Source, Berkeley Laboratory, 1 Cyclotron Road, Berkeley, California, 94720, United States * S Supporting Information ABSTRACT: The syntheses, structural characterization, and magnetic behavior of two new hexanuclear copper(II) complexes derived from R-phosphonic acids and 1,3-bis(dimethylamino)-2-propanol (Hbdmap) with formulas [Cu 6 (μ-bdmap) 3 (μ 3 -Ph- PO 3 ) 2 (μ 3 -O···H···μ 3 -O)(ClO 4 ) 2 (H 2 O)]·5H 2 O (1) and [Cu 6 (μ-bdmap) 3 (μ 3 -t-Bu-PO 3 ) 2 (μ 3 -O···H···μ 3 -O)(μ 1,3 -dca)(dca)- (H 2 O)]·6H 2 O(2)(Ph-H 2 PO 3 = phenylphosphonic acid, t-Bu-H 2 PO 3 = tert-butylphosphonic acid, dca = dicyanamide) are reported. Compounds 1 and 2 are hexanuclear 3.111 R-phosphonate(2-)/1,3-bis(dimethylamino)-2-propanolato(1-) cages including in the center the [μ 3 -O···H···μ 3 -O] 3- unit. The temperature dependence of the magnetic properties of 1 and 2 clearly indicates an overall strong antiferromagnetic coupling confirmed by DFT calculations. ■ INTRODUCTION The organophosphonate ligands, R-HPO 3 - and R-PO 3 2- (where R = CH 3 , CH 3 CH 2 , CH 3 CH 2 CH 2 ,C 6 H 5 , ...) can generate polymeric transition-metal compounds with extended layered and pillared structures. From the synthetic point of view, the described compounds are usually insoluble in the most common solvents, and to obtain single crystals suitable for the X-ray structural determination, it is often necessary to use solvatothermal reactions. 1-11 However, using organophospho- nates that bear a bulky R group in combination with ancillary ligands such as pyrazoles and pyridines, it is possible to prepare discrete transition-metal organophosphonate derivatives. 11-34 A good example are the anionic derivatives of the tert- butylphosphonic acid, t-Bu-HPO 3 - and t-Bu-PO 3 2- , which have been used as ligands with transition metals to obtain several types of polynuclear compounds with different metals and variable nuclearities: 25-34 Cu 12 , Co 12 , Cu 10 , Cu 4 , Co 4 , Mn 5 , Mn 4 , Fe 4 , Fe 10 , Mn 20 . The R-HPO 3 - and R-PO 3 2- ligands show different coordination modes in this series of polynuclear compounds. 1-34 The common ones with Harris notation are reported in Scheme 1. 35 On the other hand, the aminoalcohols 1,3-bis- (dimethylamino)-2-propanol (Hbdmap) and 1,3-bis(amino)- 2-propanol (Hbdap) can generate, after deprotonation, the anionic polytopic ligands 1,3-bis(dimethylamino)-2-propanola- to (bdmap) and 1,3-bis(amino)-2-propanolato (bdap), respec- tively, which contain anchoring N-donor atoms and alkoxo units able to act as a bridge between two or three cations. The compounds bdmap and bdap have been widely used to generate high nuclearity compounds. 36-52 The analysis of the structures reported to date shows that bdmap and bdap can use several coordination modes. 49-52 The most common coordi- nation mode of these ligands is shown in Scheme 2. We can suppose that this dinuclear [Cu 2 L] 3+ entity (L= μ-bdmap or μ- bdap) is formed when the corresponding aminoalcohol and the copper(II) salt are mixed in basic aqueous or alcoholic media. Each dinuclear [Cu 2 L] 3+ entity (complex as metal) has still other Received: March 21, 2012 Published: May 24, 2012 Scheme 1. Different Coordination Modes with Harris Notation of Phosphonic Acid Derivatives a a R= phenyl, tert-butyl. Article pubs.acs.org/IC © 2012 American Chemical Society 6842 dx.doi.org/10.1021/ic300589h | Inorg. Chem. 2012, 51, 6842-6850