Nitratotris(triphenylphosphine)copper(I) methanol solvate

The title compound, [Cu(NO3)(C18H15P)3]·CH3OH, is a methanol solvate derivative of nitratotris(triphenylphosphine)copper(I). The complex crystallizes with three triphenylphosphine ligands coordinated to the copper centre, with an O—H⋯O hydrogen bond observed between the nitrate ligand and the methanol solvent molecule. The coordination around the CuI centre is distorted tetrahedral.

The title compound, [Cu(NO 3 )(C 18 H 15 P) 3 ]ÁCH 3 OH, is a methanol solvate derivative of nitratotris(triphenylphosphine)copper(I). The complex crystallizes with three triphenylphosphine ligands coordinated to the copper centre, with an O-HÁ Á ÁO hydrogen bond observed between the nitrate ligand and the methanol solvent molecule. The coordination around the Cu I centre is distorted tetrahedral.
Financial assistance from the University of the Free State and Professor A. Roodt is gratefully acknowledged. Mr L. Kirsten is acknowledged for the the data collection. Part of this material is based on work supported by the South African National Research Foundation (NRF) under grant No. GUN 2068915. Opinions, findings, conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the NRF.

Comment
The title compound, (I), is an example of a methanol solvate of a previously published ethanol solvate complex (Dyason et al., 1986). Both complexes crystallize in the P2 1 /n space group with similar cell lengths and angles. The inclusion of a methanol solvate compared to a ethanol solvate molecule is best illustrated in the cell volume increase from 4758 to 4909 Å 3 .
The Cu-P bond distances differ from each other in the title compound, Table 1, with one triphenyl phosphine moiety (P2) being slightly closer to the copper metal centre compared to the remaining ligands. An intermolecular hydrogen bond is observed between the solvate molecule and the nitrato moiety coordinated to the copper centre, Table 2.
The ethanol complex (Dyason et al., 1986) is closely related to the title compound with only minor differences in bond lengths and angles. A similar hydrogen bond is observed between the solvate molecule and the nitrato moiety in each of these compounds. The O···O bond distance increases from 2.772 to 2.835 Å from the ethanol to the methanol solvate system.

Experimental
The title complex was synthesised by recrystallizing the [Cu(PPh 3 ) 2 NO 3 ] complex from hot methanol. On slow evaporation of the solvent; yellow crystals suitable for X-Ray crystallography was obtained.

Refinement
H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 (C aromatic) and 0.99 (methyl) Å and U iso (H) = 1.2 times U eq . Fig. 1. : Representation of the title compound (I), showing the numbering scheme and displacement ellipsoids (50 % probability). For the carbon rings on the triphenylphosphine ligands, the first digit refers to phosphorous number, second digit to the ring number and third digit to atom in the ring. Hydrogen atoms omitted for clarity.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )