TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Preparing metal-carbene complex involves reacting metal-carbene complex of formula (X) with a compound of formula (vii).X1=Cl, Br, or I, especially Br;Y'=-B(OH)2, -B(OY1)2 or formula (viii) or (ix); -SnR307R308R309; ZnR310R311; or SiR312R313R314;Y1=independently in each occurrence a 1-10C alkyl group;Y2=independently in each occurrence a 2-10C alkylene group, such as - CY3Y4-CY5Y67-, or -CY7Y8-CY9Y10-CY11Y12-;Y3-Y12=independently of each other, hydrogen, or a (1-10C)alkyl group, especially -C(CH3)2C(CH3)2-, -CH2C(CH3)2CH2-, or -C(CH3)2CH2C(CH3)2-;Y13 and Y14=independently of each other, hydrogen, or a (1-10C)alkyl group;R307, R308, and R309=identical or different, H or 1-6C alkyl, where two radicals optionally form a common ring and these radicals are optionally branched or unbranched;R310=halo;R311=a (1-10C)alkyl group, a 6-12C aryl group, or (1-10C)alkenyl group; andR312, R313, and R314=identical or different, and are halogen, or 1-6C alkyl.The process involves reacting metal-carbene complex of formula (XI) with a halogenating agent to obtain metal-carbene complex of formula (X). Full Definitions:    M=Pt, or Ir; if M is Ir, m is 1 , 2, or 3; o is 0, 1 , or 2; and the sum of m + o is 3; with the proviso that, if o is 2, the ligands L may be the same or different; if M is Pt, m is 1, or 2; o is 0, or 1; and the sum of m + o is 2;    L=a monoanionic bidentate ligand;    R=a group of formula (i);    R'=H, 1-5C alkyl group, or a fluoro(1-4C)alkyl group;    R1=H, a 1-5C alkyl group, a fluoro(1-4C)alkyl group, or a 3-6C cycloalkyl group;    R2=H, a 1-5C alkyl group, a fluoro(1-4C)alkyl group, or a 3-6C cycloalkyl group;    R3, R3', and R3''=independently of each other, hydrogen; a 1-18C alkyl group, which can optionally be substituted by E and/or interrupted by D; a (3-12C)cycloalkyl group, which can optionally be substituted by G; a 3-10C heterocycloalkyl radical which is interrupted by at least one of O, S and NR65 and/or substituted by E; a 6-24C aryl group, which can optionally be substituted by G; or a 2-30C heteroaryl group, which can optionally be substituted by G; a halogen atom, especially F or Cl, CF3, CN, or SiR80R81R82; where R3 and R3', or R1 and R3' together form a group of formula (ii);    X=O, S, NR75 or CR73R74;    R4, R4' and R5=independently of each other, hydrogen; a 1-18C alkyl group, which can optionally be substituted by E and/or interrupted by D; a (3-12C)cycloalkyl group, which can optionally be substituted by E; a (3-10C)heterocycloalkyl radical which is interrupted by at least one of O, S and NR65 and/or substituted by E; a 6-14C aryl group, which can optionally be substituted by G; or a 2-10C heteroaryl group, which can optionally be substituted by G; a halogen atom, especially F or Cl, CF3, CN, or R4 and R4' together form a group of formula (iii) or (iv);    R6 and R7=independently of each other hydrogen, a 1-8C alkyl group, optionally interrupted by at least one heteroatom selected from -O-, -S- and -NR65-, optionally bearing at least one substituent, which is selected from the group consisting of 1-8C alkyl, 1-8C alkoxy, halogen, preferably F, and 1-8C haloalkyl, such as CF3; a (3-6C)cycloalkyl group, optionally bearing at least one substituent, which is selected from 1-8C alkyl, 1-8C alkoxy, halogen, preferably F, 1-8C haloalkyl, such as CF3; a hetero 3-6C cyclo alkyl group, interrupted by at least one heteroatom selected from -O-, -S- and -NR65-, optionally bearing at least one substituent, which is selected from 1-8C alkyl, 1-8C alkoxy, halogen, preferably F, 1-8C haloalkyl, such as CF3; or a 6-14C arylgroup, which can optionally be substituted by one, or two 1-8C alkyl groups; or R6 and R7 form together a ring of formula (v) or (vi);    A21, A21', A22, A22', A23, A23', A24' and A24=independently of each other, H, a 1-4C alkyl group, a 3-6C cycloalkyl group, a fluoro-1-4C alkyl group;    D=-CO-, -COO-, -S-, -SO-, -SO2-, -O-, -NR65-, -SiR70R71-, -POR72-, -CR63=CR64-, or -C?=C;    E=-OR69, -SR69, -NR65R66, -COR68, -COOR67, -CONR65R66, -CN, or F;    G=E, or a 1-18 alkyl group, a 6-14C aryl group, a 6-14C aryl group, which is substituted by F, 1-18C alkyl, or 1-18Calkyl, which is substituted by F and/or interrupted by O; a 2-10C heteroaryl group, or a 2-10C heteroaryl group, which is substituted by F, 1-18C alkyl, SiR80R81R82, or 1-8C alkyl which is substituted by F and/or interrupted by O;    R63 and R64=independently of each other H, 6-18C aryl; 6-18C aryl which is substituted by 1-18C alkyl, or 1-18C alkoxy; 1-18C alkyl; or 1-18C alkyl which is interrupted by -O-;    R65 and R66=independently of each other a 6-18C aryl group; a 6-18C aryl which is substituted by 1-18C alkyl, or 1-18C alkoxy; a 1-18C alkyl group; or a 1-18C alkyl group, which is interrupted by -O-; or R65 and R66 together form a five or six membered ring;    R67 and R68=a 6-18C aryl group; a 6-18C aryl group, which is substituted by 1-18C alkyl, or 1-18C alkoxy; a 1-18C alkyl group; or a 1-18C alkyl group, which is interrupted by -O-;    R69=a (6-18C)aryl; a (6-18C)aryl, which is substituted by (1-18C)alkyl, or 1-18C alkoxy; a (1-18C)alkyl group; or a (1-18C)alkyl group, which is interrupted by -O-;    R70, R71, and R72=independently of each other, a (1-18C)alkyl group, a 6-18C aryl group, or a (6-18C)aryl group, which is substituted by (1-18C)alkyl;    R73 and R74=independently of each other H, 1-25C alkyl, 1-25C alkyl which is interrupted by O, 7-25C arylalkyl, 6-24C aryl, 6-24C aryl which is substituted by (1-18C)alkyl, 2-20C heteroaryl, or 2-20C heteroaryl which is substituted by (1-18C)alkyl; or R73 and R747together form a group of formula =CR76R77;    R76 and R77=independently of each other H, (1-18C)alkyl, (1-18C)alkyl which is interrupted by O, 6-24C aryl, 6-24C aryl which is substituted by (1-18C)alkyl, or 2-20C heteroaryl, or 2-20C heteroaryl which is substituted by (1-18C)alkyl, or R73 and R74 together form a five or six membered ring, which optionally can be substituted by (1-18C)alkyl, (1-18C)alkyl which is interrupted by O;    R75=a (6-18C)aryl group; a 6-18C aryl which is substituted by (1-18C)alkyl, or 1-18C alkoxy; a (1-18C)alkyl group; or a (1-18C)alkyl group, which is interrupted by -O-, and    R80, R81, and R82=independently of each other a 1-25C alkyl group, which can optionally be interrupted by O; a 6-14C arylgroup, which can optionally be substituted by (1-18C)alkyl; or a 2-10C heteroaryl group, which can optionally be substituted by (1-18C)alkyl.    EXAMPLE - No suitable example given.