Synthesis and Molecular Structure of cis-Tetracarbonyl[N-(diphenylphosphino-kP)-naphthalen-1-yl-P,P-diphenylphosphinous amide-kP]chromium(0)

The reaction of N,N-bis(diphenylphosphanyl)naphthylamine C10H7-1-N(PPh2)2 with (C5H10NH)2Cr(CO)4 (1？:？1 molar ratio) in dichloromethane afforded cis-[Cr(CO)4 C10H7-1-N(PPh2)2 ] (1). This complex was crystallized in the monoclinic space group P21/n. The structure was solved by direct methods and refined by full-matrix least squares techniques to an factor of 0.0313 for 6488 observed reflections. The Cr-metal is coordinated by four terminal CO molecules and a P,P′-bidentate N,N-bis(diphenylphosphanyl)naphthylamine ligand in a distorted octahedral array. The N-atom adopts a planar geometry with the two P-atoms and C-atom attached to it. The four-membered metallacycle ring P2CrN is nearly planar. 1. Introduction As a continuation of our work on the synthesis and solid-state structures of phosphorus(III) ligands containing direct P–N bonds and derivatives [1–4], as these have shown a broad spectrum of anticancer, herbicidal, neuroactive, and antimicrobial activities [5–9], thereof, herein we report the synthesis and crystal structure of cis-[Cr(CO)4{C10H7-1-N(PPh2)2}] (1). 2. Materials and Methods 2.1. Chemistry All experiments were carried out under purified dry nitrogen using standard Schlenk and vacuum line techniques. Solvents were dried and freshly distilled under nitrogen [10]. The chemicals Cr(CO)6 were used as purchased. C10H7-1-N(PPh2)2 [1] and (C5H10NH)2Cr(CO)4 [11] were prepared according to the literature methods. Infrared spectra were recorded on a Shimadzu FTIR-8400S spectrometer between 4000 and 400？cm？1 using KBr disks. The NMR spectra were recorded at 25°C on a Bruker-Avance-DRX-400？MHz NMR spectrometer operating at 400.17 (1H) and 100.63 (13C) using tetramethylsilane as external standard. Melting point was carried out on a Gallenkamp apparatus with open capillaries. 2.2. Preparation of cis-Tetracarbonyl[N-(diphenylphosphino-kP)-naphthalen-1-yl-P,P-diphenylphosphinous amide-kP]chromium(0) (1) A solution of N,N-bis(diphenylphosphanyl)naphthylamine (0.26？g, 0.51？mmol) and (C5H10NH)2Cr(CO)4 (0.17？g, 0.51？mmol) in 20？mL of CH2Cl2 was refluxed for 2？h. The orange solution was concentrated to ca. 5？mL under reduced pressure, and n-hexane (5？mL) was added. Cooling this solution to 0°C gave 3 as yellow crystals in 85% yield. Mp 180–183°C. 1H NMR (CDCl3, /ppm): 6.40–7.78 (m, 27？H, C10H7 and 4C6H5). 13C NMR (CDCl3, /ppm): 124.8, 125.2, 125.6, 125.9, 127.1, 127.9, 128.6, 129.6, 130.5, 131.3, 132.6, 134.1, 135.4, 138.8 (C10H6 and 4C6H5), 221.2 ( ), 228.2 ( ). 31P NMR (CDCl3, /ppm): 117.41 (s, 2P). IR (selected bands, KBr, cm？1): (s, br), 1920 (s), 2008