Molecular Formula: C₁₃H₁₉O₂Rh
Molar mass: 310.1943 g/mol
Melting point: 138-140 °C(lit.)
Storage temp: Below 5° C
Sensitive: Air Sensitive
Appearance: Orange crystal
Product categories: Metal-organic matter
Structure of (1,5-Cyclooctadiene)(2,4-pentanedionato)rhodium (CAS NO.12245-39-5):
                 

Carcinogenicity of (1,5-Cyclooctadiene)(2,4-pentanedionato)rhodium (CAS NO.12245-39-5) hasn't been listed as a carcinogen by NTP, IARC,ACGIH, or CA Prop 65. And its toxicological properties have not been fully investigated.You can see actual entry in RTECS for complete information.

Poison by intraperitoneal route. When heated to decomposition it emits toxic fumes of Rh.
 

Hazard Codes: Xi
Risk Statements: 36/37/38
R36/37/38:Irritating to eyes, respiratory system and skin.
Safety Statements: 26-37/39
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S37/39:Wear suitable gloves and eye/face protection.

OSHA PEL: TWA 0.1 mg(Rh)/m³
ACGIH TLV: TWA 1 mg(Rh)/m³

 (1,5-Cyclooctadiene)(2,4-pentanedionato)rhodium ,its cas register number is 12245-39-5. It also can be called Rhodium, (1,5-cyclooctadiene)(2,4-pentanedionato)- ; Rhodium, ((1,2,5,6-eta)-1,5-cyclooctadiene)(2,4-
pentanedionato-O,O')- ; Acetylacetonate-1,5-cyclooctadiene rhodium and (1,5-Cyclooctadiene)(acetylacetonato)rhodium .
 (1,5-Cyclooctadiene)(2,4-pentanedionato)rhodium (CAS NO.12245-39-5) is hazardous,so the first aid measures and others should be known. Such as: When on the skin: first,should flush skin with plenty of water immediately for at least 15 minutes while removing contaminated clothing. Secondly,Get medical aid. Or in the eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Then get medical aid soon. While ,it's Inhaled: Remove from exposure and move to fresh air immediately.Give artificial respiration while not breathing. When breathing is difficult, give oxygen. And as soon as to get medical aid. Then you have the ingesting of the product : Wash mouth out with water,and get medical aid immediately.
In addition, (1,5-Cyclooctadiene)(2,4-pentanedionato)rhodium (CAS NO.12245-39-5) is moisture sensitive with air. It is not compatible with strong oxidizing agents, and you must not take it with ignition sources and incompatible materials and not be exposured to moist air or water.And also prevent it to broken down into hazardous decomposition products: carbon dioxide, carbon monoxide.