Non-linear optical materials containing molybdenum or tungsten mononitrosyl redox centres: diaromatic azo derivatives

Abstract

The following compounds have been prepared: [M(NO)L(X)_n{EC₆H₃(R-3)[NNC₆H₃(R′-3)(R″-4)-4]}_{2 – n}][L = tris(3,5-dimethylpyrazolyl)hydroborate; R″=(η⁵-C₅H₄)Fe(η⁵-C₅H₅), E = O, R = R′= H, M = Mo, X = Cl or I, n= 0 or 1; E = NH, R = R′= H, n= 1, M = Mo or W, X = Cl; E = NH, R = Me, R′= H, n= 1, M = Mo, X = F, Cl, Br, I or OC₆H₁₁; M = W, X = Cl; E = NH, R = R′= Me, n= 1, M = Mo, X = Cl or I; M = W, X = Cl; R″= NMe₂, E = O, R = R′= H, M = Mo, X = Cl or I. n= 0 or 1; M = W, X = Cl, n= 1; E = NH, R = R′= H, n= 1, M = Mo, X = Cl or I; M = W, X = Cl], [M(NO)-L(X){OC₁₀H₆[NNC₆H₄(OEt-4)-4]}](M = Mo, X = Cl or I; M = W, X = Cl) and [Mo(NO)L(Cl)-(NHC₆H₃(Me-3){NNC₆H₃(Me-3)[NNC₆H₃(Me-3)(R″-4)-4]}-4)]. Several of the ferrocenyl derivatives have been found to produce frequency doubling of radiation at 1907 nm, whereas the derivatives containing NMe₂ or OEt groups do not. A single-crystal X-ray diffraction study has shown that [W(NO)LCl{NHC₆H₃(Me-3)[NNC₆H₄(R″-4)]-4}]·CH₂Cl₂ crystallises in the space group P2₁ and is isostructural with its molybdenum counterpart; in these crystals the molecules appear to be favourably oriented to produce phase matching.